2,666 research outputs found
FIGGS: Faint Irregular Galaxies GMRT Survey
The Faint Irregular Galaxies GMRT Survey (FIGGS) is a large program aimed at
providing a comprehensive and statistically robust characterisation of the
neutral ISM properties of faint (M_B > -14.5), nearby, gas rich, dwarf
irregular galaxies using the Giant Metrewave Radio Telescope (GMRT). Here we
briefly describe the survey and discuss some of the science that we anticipate
can be done with this data set.Comment: 4 Pages, 3 Figures. To be published in the proceedings of "Galaxies
in the Local Volume", ed. B. Koribalski, H. Jerje
Suitability of FRIs based on Generalised Operators
It is well known that a t-norm
T
and its residual implication
I
T
, normally denoted as the
residual pair (
T;I
T
), play an important role in fuzzy inference systems, especially in Fuzzy
Relational Inference (FRI) mechanisms. For instance, many desirable properties like the inter-
polativity, continuity, robustness and monotonicity of an FRI largely depend on the properties
possesed by the residual pair (
T;I
T
)
Cold HI in faint dwarf galaxies
We present the results of a study of the amount and distribution of cold
atomic gas, as well its correlation with recent star formation in a sample of
extremely faint dwarf irregular galaxies. Our sample is drawn from the Faint
Irregular Galaxy GMRT Survey (FIGGS) and its extension, FIGGS2. We use two
different methods to identify cold atomic gas. In the first method,
line-of-sight HI spectra were decomposed into multiple Gaussian components and
narrow Gaussian components were identified as cold HI. In the second method,
the brightness temperature (T_B) is used as a tracer of cold HI. We find that
the amount of cold gas identified using the T_B method is significantly larger
than the amount of gas identified using Gaussian decomposition. We also find
that a large fraction of the cold gas identified using the T_B method is
spatially coincident with regions of recent star formation, although the
converse is not true. That is only a small fraction of the regions with recent
star formation are also covered by cold gas. For regions where the star
formation and the cold gas overlap, we study the relationship between the star
formation rate density and the cold \HI column density. We find that the star
formation rate density has a power law dependence on the HI column density, but
that the slope of this power law is significantly flatter than that of the
canonical Kennicutt-Schmidt relation.Comment: Accepted for publication in MNRA
Bandler–Kohout Subproduct With Yager’s Classes of Fuzzy Implications
The Bandler-Kohout subproduct (BKS) inference mechanism is one of the two established fuzzy relational inference (FRI) mechanisms; the other one being Zadeh's compositional rule of inference (CRI). Both these FRIs are known to possess many desirable properties. It can be seen that many of these desirable properties are due to the rich underlying structure, viz., the residuated algebra, from which the employed operations come. In this study, we discuss the BKS relational inference system, with the fuzzy implication interpreted as Yager's classes of implications, which do not form a residuated structure on [0,1] . We show that many of the desirable properties, viz., interpolativity, continuity, robustness, which are known for the BKS with residuated implications, are also available under this framework, thus expanding the choice of operations available to practitioners. Note that, to the best of the authors' knowledge, this is the first attempt at studying the suitability of an FRI where the operations come from a nonresiduated structure
HI power spectrum of the spiral galaxy NGC628
We have measured the HI power spectrum of the nearly face-on spiral galaxy
NGC628 (M74) using a visibility based estimator. The power spectrum is well
fitted by a power law , with over the
length scale . The slope is found to be
independent of the width of the velocity channel. This value of the slope is a
little more than one in excess of what has been seen at considerably smaller
length scales in the Milky-Way, Small Magellanic Cloud (LMC), Large Magellanic
Cloud (SMC) and the dwarf galaxy DDO210. We interpret this difference as
indicating a transition from three dimensional turbulence at small scales to
two dimensional turbulence in the plane of the galaxy's disk at length scales
larger than galaxy's HI scale height.
The slope measured here is similar to that found at large scales in the LMC.
Our analysis also places an upper limit to the galaxy's scale height at $800\
{\rm pc}$ .Comment: 4 Pages, 2 Figures, 1 Table. Accepted for Publication in MNRAS
LETTER
Programming Robots With Events
International audienceWe introduce how to use event-based style to program robots through the INI programming language. INI features both built-in and user-defined events, a mechanism to handle various kinds of changes happening in the environment. Event handlers run in parallel either synchronously or asynchronously, and events can be reconfigured at runtime to modify their behavior when needed. We apply INI to the humanoid robot called Nao, for which we develop an object tracking program
High pressure X-ray preionized TEMA-CO2 laser
The construction of a high-pressure (up to 20 atm) transversely excited CO2 laser using transverse X-ray preionization is described. High pressure operation was found to be greatly improved in comparison to UV-preionized systems. Homogeneous discharges have been achieved in the pressure range 5–20 atm, yielding a specific laser output in the order of 35 J/l
The Taste of Carbonation
Carbonated beverages are commonly available and immensely popular, but little is known about the cellular and molecular mechanisms underlying the perception of carbonation in the mouth. In mammals, carbonation elicits both somatosensory and chemosensory responses, including activation of taste neurons. We have identified the cellular and molecular substrates for the taste of carbonation. By targeted genetic ablation and the silencing of synapses in defined populations of taste receptor cells, we demonstrated that the sour-sensing cells act as the taste sensors for carbonation, and showed that carbonic anhydrase 4, a glycosylphosphatidylinositol-anchored enzyme, functions as the principal CO_2 taste sensor. Together, these studies reveal the basis of the taste of carbonation as well as the contribution of taste cells in the orosensory response to CO_2
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