1,004 research outputs found
The morphology of public open spaces as visual opportunity fields: a space syntax approach based on revelation and VGA maps customization with SalaScript
This paper explores the visual dynamics of the morphology of public open spaces. Resorting to space syntax concepts, visual graph analysis (VGA), and the innovative use of its standard tool Depthmap, a set of case studies is analysed under the perspective of visual opportunity fields and building upon the established concept and metrics of Revelation. A series of related novel measures and visualizations are developed, which are only possible, in Depthmap environment, by the advanced use of its scripting language: SalaScript. Despite Depthmap being the standard tool among the space syntax community, there is a lack of references to the explicit use of SalaScript. One major objective of this paper is to illustrate, and document, its possibilities to a broad audience by extending, customizing and introducing a more interactive approach in handling VGA maps. We present SalaScript functionalities and its use in the development of visual analysis scripts that allow the study of revelation, which we then apply to a set of real public open spaces case studies.info:eu-repo/semantics/publishedVersio
Enhanced dust heating in the bulges of early-type spiral galaxies
Stellar density and bar strength should affect the temperatures of the cool (T ~ 20–30 K) dust component in the inner regions of galaxies, which implies that the ratio of temperatures in the circumnuclear regions to the disk should depend on Hubble type. We investigate the differences between cool dust temperatures in the central 3 kpc and disk of 13 nearby galaxies by fitting models to measurements between 70 and 500 μm. We attempt to quantify temperature trends in nearby disk galaxies, with archival data from Spitzer/MIPS and new observations with Herschel/SPIRE, which were acquired during the first phases of the Herschel observations for the KINGFISH (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel) sample. We fit single-temperature modified blackbodies to far-infrared and submillimeter measurements of the central and disk regions of galaxies to determine the temperature of the component(s) emitting at those wavelengths. We present the ratio of central-region-to-disk-temperatures of the cool dust component of 13 nearby galaxies as a function of morphological type. We find a significant temperature gradient in the cool dust component in all galaxies, with a mean center-to-disk temperature ratio of 1.15 ± 0.03. The cool dust temperatures in the central ~3 kpc of nearby galaxies are 23 (±3)% hotter for morphological types earlier than Sc, and only 9 (±3)% hotter for later types. The temperature ratio is also correlated with bar strength, with only strongly barred galaxies having a ratio over 1.2. The strong radiation field in the high stellar density of a galactic bulge tends to heat the cool dust component to higher temperatures, at least in early-type spirals with relatively large bulges, especially when paired with a strong bar
Is it possible to store spotted wolffish (Anarhichas minor) sperm by refrigeration?
Spotted wolffish Anarhichas minor reproduction in captivity is dependent on in vitro fertilization. However, it is often challenging to acquire sufficient fresh sperm to fertilize the eggs that are obtained. In this study, we evaluate the possibility to store spotted wolffish sperm by refrigeration. Spotted wolffish sperm has the particularity that is already motile on stripping, and currently it is not possible to immobilize and reactivate. Thus, sperm refrigeration protocols should focus in extending this motility period that usually lasts up to 2 days. In a first experiment, we evaluated the possibility that the motility period of the sperm was limited by contamination with urine. The urea concentration in the sperm obtained both by stripping (17.10 ± 1.98 mg/dL) and directly from the testis (12.59 ± 2.37 mg/dL) was similar (p > 0.05), which indicate that the sperm collection method used avoid contamination with urine. Afterwards, we tested the possibility that the sperm motility period was limited by energy stores. The ATP concentration (initial value 5.65 ± 0.86 nmol/109 cells) remained stable (p = 0.099) during 30 h after sperm collection, and similar values (p = 0.329) were recorded at end of sperm storage in both diluted (3.88 ± 1.35 nmol/109 cells) and undiluted samples (4.76 ± 1.08 nmol/109). This indicates that the low intracellular ATP consumption, derived from the slow sperm motility, can probably be compensated rapidly enough by mitochondrial synthesis of ATP in the spotted wolffish sperm. In both experiments, diluted sperm kept higher percentage of motile cells during the storage time.info:eu-repo/semantics/publishedVersio
Multidimensional study of urban squares through perimetral analysis: three Portuguese case studies
This paper addresses one of the most symbolically and socially meaningful elements of the public open space: the urban square (Portuguese: praça). Besides their urban centrality, these spaces’ potential for liveliness depends on multiple factors and their identity as a place may only be grasped by formal methods that embrace that latent complexity and address the multi?scale and multivariate correlations of factors that defy human cognitive capabilities. This paper will present a synchronic multidimensional analysis of three Portuguese historic squares: Praça da Oliveira, Praça de Santiago (Guimarães) and Praça do Giraldo (Évora), representative of the national historic heritage.info:eu-repo/semantics/acceptedVersio
On the regularity up to the boundary for certain nonlinear elliptic systems
We consider a class of nonlinear elliptic systems and we prove regularity up to the boundary for second order derivatives. In the proof we trace carefully the dependence on the various parameters of the problem, in order to establish, in a further work, results for more general systems
Vanishing Viscous Limits for 3D Navier-Stokes Equations with A Navier-Slip Boundary Condition
In this paper, we investigate the vanishing viscosity limit for solutions to
the Navier-Stokes equations with a Navier slip boundary condition on general
compact and smooth domains in . We first obtain the higher order
regularity estimates for the solutions to Prandtl's equation boundary layers.
Furthermore, we prove that the strong solution to Navier-Stokes equations
converges to the Eulerian one in and
L^\infty((0,T)\times\o), where is independent of the viscosity, provided
that initial velocity is regular enough. Furthermore, rates of convergence are
obtained also.Comment: 45page
Spatially Resolved Spitzer-IRS Spectroscopy of the Central Region of M82
We present high spatial resolution (~ 35 parsec) 5-38 um spectra of the
central region of M82, taken with the Spitzer Infrared Spectrograph. From these
spectra we determined the fluxes and equivalent widths of key diagnostic
features, such as the [NeII]12.8um, [NeIII]15.5um, and H_2 S(1)17.03um lines,
and the broad mid-IR polycyclic aromatic hydrocarbon (PAH) emission features in
six representative regions and analysed the spatial distribution of these lines
and their ratios across the central region. We find a good correlation of the
dust extinction with the CO 1-0 emission. The PAH emission follows closely the
ionization structure along the galactic disk. The observed variations of the
diagnostic PAH ratios across M82 can be explained by extinction effects, within
systematic uncertainties. The 16-18um PAH complex is very prominent, and its
equivalent width is enhanced outwards from the galactic plane. We interpret
this as a consequence of the variation of the UV radiation field. The EWs of
the 11.3um PAH feature and the H_2 S(1) line correlate closely, and we conclude
that shocks in the outflow regions have no measurable influence on the H_2
emission. The [NeIII]/[NeII] ratio is on average low at ~0.18, and shows little
variations across the plane, indicating that the dominant stellar population is
evolved (5 - 6 Myr) and well distributed. There is a slight increase of the
ratio with distance from the galactic plane of M82 which we attribute to a
decrease in gas density. Our observations indicate that the star formation rate
has decreased significantly in the last 5 Myr. The quantities of dust and
molecular gas in the central area of the galaxy argue against starvation and
for negative feedback processes, observable through the strong extra-planar
outflows.Comment: 15 pages, 12 figures, 3 tables, ApJ, emulateap
Powerful H Emission and Star Formation on the Interacting Galaxy System Arp 143: Observations with Spitzer and GALEX
We present new mid-infrared (m) and ultraviolet (1539 -- 2316 \AA)
observations of the interacting galaxy system Arp 143 (NGC 2444/2445) from the
Spitzer Space Telescope and GALEX. In this system, the central nucleus of NGC
2445 is surrounded by knots of massive star-formation in a ring-like structure.
We find unusually strong emission from warm H associated with an expanding
shock wave between the nucleus and the western knots. At this ridge, the flux
ratio between H and PAH emission is nearly ten times higher than in the
nucleus. Arp 143 is one of the most extreme cases known in that regard. From
our multi-wavelength data we derive a narrow age range of the star-forming
knots between 2 Myr and 7.5 Myr, suggesting that the ring of knots was formed
almost simultaneously in response to the shock wave traced by the H
emission. However, the knots can be further subdivided in two age groups: those
with an age of 2--4 Myr (knots A, C, E, and F), which are associated with
m emission from PAHs, and those with an age of 7-8 Myr (knots D and G),
which show little or no m emission shells surrounding them. We attribute
this finding to an ageing effect of the massive clusters which, after about 6
Myr, no longer excite the PAHs surrounding the knots.Comment: 19 pages, 11 figures, including tables at the end; accepted by Ap
Uniform regularity for the Navier-Stokes equation with Navier boundary condition
We prove that there exists an interval of time which is uniform in the
vanishing viscosity limit and for which the Navier-Stokes equation with Navier
boundary condition has a strong solution. This solution is uniformly bounded in
a conormal Sobolev space and has only one normal derivative bounded in
. This allows to get the vanishing viscosity limit to the
incompressible Euler system from a strong compactness argument
Viscous-Inviscid Interactions in a Boundary-Layer Flow Induced by a Vortex Array
In this paper we investigate the asymptotic validity of boundary layer
theory. For a flow induced by a periodic row of point-vortices, we compare
Prandtl's solution to Navier-Stokes solutions at different numbers. We
show how Prandtl's solution develops a finite time separation singularity. On
the other hand Navier-Stokes solution is characterized by the presence of two
kinds of viscous-inviscid interactions between the boundary layer and the outer
flow. These interactions can be detected by the analysis of the enstrophy and
of the pressure gradient on the wall. Moreover we apply the complex singularity
tracking method to Prandtl and Navier-Stokes solutions and analyze the previous
interactions from a different perspective
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