3,424 research outputs found
Disjoint Dominating Sets with a Perfect Matching
In this paper, we consider dominating sets and such that and
are disjoint and there exists a perfect matching between them. Let
denote the cardinality of smallest such sets in
(provided they exist, otherwise ). This
concept was introduced in [Klostermeyer et al., Theory and Application of
Graphs, 2017] in the context of studying a certain graph protection problem. We
characterize the trees for which equals a certain
graph protection parameter and for which ,
where is the independence number of . We also further study this
parameter in graph products, e.g., by giving bounds for grid graphs, and in
graphs of small independence number
Theoretical advances on Economic Model Predictive Control with time-varying costs
© 2016 Published by Elsevier Ltd on behalf of International Federation of Automatic Control.Economic Model Predictive Control is a technique for optimization of economic revenues arising from controlled dynamical processes that has established itself as a variant of standard Tracking Model Predictive Control. It departs from the latter in that arbitrary cost functions are allowed in the formulation of the stage cost. This paper takes a further step in expanding the applicability of Economic Model Predictive Control by illustrating how the paradigm can be adapted in order to accommodate time-varying or parameter-varying costs
Outer structure of the Galactic warp and flare: explaining the Canis Major over-density
(Abridged) We derive the structure of the Galactic stellar Warp and Flare
using 2MASS RC and RGB stars, selected at mean heliocentric distances of 3, 7
and 17 kpc.
Our results are: (i) a clear stellar warp signature is derived for the 3
selected rings; (ii) the derived stellar warp is consistent (both in amplitude
and phase-angle) with that for the Galactic interstellar dust and HI gas; (iii)
the Sun seems not to fall on the line of nodes. The stellar warp phase-angle
orientation (+15 degrees) is close to the orientation angle of the Galactic bar
and this produces an asymmetric warp for the inner rings; (iv) a
Northern/Southern warp symmetry is observed only for the ring at 17 kpc; (v)
treating a mixture of thin and thick disk populations we trace the disk flaring
and derive a constant scale-height (~0.65 kpc) within R(GC)~15 kpc. Further
out, the disk flaring increase gradually reaching a mean scale-height of ~1.5
kpc at R(GC)~23 kpc; and (vi) these results provide further robust evidence
that there is no disk radial truncation at R(GC)~14 kpc.
In the particular case of the Canis Major over-density we confirm its
coincidence with the Southern stellar maximum warp occurring near l=240. We
present evidence to conclude that all observed parameters (e.g. number density,
radial velocities, proper motion etc) of CMa are consistent with it being a
normal Milky Way outer-disk population, thereby leaving no justification for a
more complex interpretations of its origin. The present analysis does not
provide a conclusive test of the structure or origin of the Monoceros Ring.
Nevertheless, we show that a warped flared Milky Way contributes significantly
at the locations of the Monoceros Ring.Comment: 25 pages, 22 figures, accepted for publication in A&A. A higher
resolution pdf file is available at
http://wwwuser.oat.ts.astro.it/zaggia/public_html/warp
Structural properties of a calcium aluminosilicate glass from molecular-dynamics simulations: A finite size effects study
We study a calcium aluminosilicate glass of composition
(SiO)-(AlO)-(CaO) by means of
molecular-dynamics (MD) simulations, using a potential made of two-body and
three-body interactions. In order to prepare small samples that can
subsequently be studied by first-principles, the finite size effects on the
liquid dynamics and on the glass structural properties are investigated. We
find that finite size effects affect the Si-O-Si and Si-O-Al angular
distributions, the first peaks of the Si-O, Al-O and Ca-O pair correlation
functions, the Ca coordination and the oxygen atoms environment in the smallest
system (100 atoms). We give evidence that these finite size effects can be
directly attributed to the use of three-body interactions.Comment: 36 pages, 14 figures. Journal of Chem. Phys., in pres
Socio-cultural sustainability of private healthcare providers in an Indian slum setting: A bottom-of-the-pyramid perspective
Delivery of affordable healthcare services to communities is a necessary precondition to
poverty alleviation. Co-creation approaches to the development of business models in the healthcare
industry proved particularly suitable for improving the health-seeking behavior of BOP patients.
However, scant research was conducted to understand BOP consumers’ decision-making process
leading to specific healthcare choices in slum settings, and the relative balance of socio-cultural
and socio-economic factors underpinning patients’ preferences. This article adopts a mixed-method
approach to investigate the determinants of BOP patients’ choice between private and public hospitals.
Quantitative analysis of a database, composed of 436 patients from five hospitals in Ahmedabad,
India, indicates that BOP patients visit a public hospital significantly more than top-of-the-pyramid
(TOP) patients. However, no significant difference emerges between BOP and TOP patients for
inpatient or outpatient treatments. Qualitative findings based on 21 interviews with BOP consumers
from selected slum areas led to the development of a grounded theory model, which highlights
the role of aspirational demand of BOP patients toward private healthcare providers. Overall,
healthcare provider choice emerges as the outcome of a collective socio-cultural decision-making
process, which often assigns preference for private healthcare services because of the higher perceived
quality of private providers, while downplaying affordability concerns. Implications for healthcare
providers, social entrepreneurs, and policy-makers are discussed
Preferential expression of the transcription coactivator HTIF1alpha gene in acute myeloid leukemia and MDS-related AML
HTIF1α, a transcription coactivator which is able to mediate RARα activity and functionally interact with PML, is encoded by a gene on chromosome 7q32–34, which is a critical region in acute myeloid leukemias (AML). With the assumption that this gene may be related to AML, we investigated the HTIF1α DNA structure and RNA expression in leukemic cells from 36 M1–M5 AML patients (28 ‘de novo’ and eight ‘secondary’ to myelodysplastic syndrome (MDS)). Abnormal HTIF1α DNA fragments were never found, whereas loss of HTIF1α DNA was observed in the patients with chromosome 7q32 deletion and translocation, and in one case without detectable chromosome 7 abnormality. HTIF1α RNA was found in acute myelocytic leukemic blasts, and was almost undetectable in normal mononuclear cells. The expression varied among the patients: higher in M1 to M3 subtypes, with the highest values in M1; low levels were constantly observed in M4 and M5 AML. In addition, HTIF1α was significantly overexpressed in MDS-related AML (MDR-AML), but not in MDS. We also found that HTIF1α expression was high in myeloid cell lines. In myeloblastic HL60 and promyelocytic NB4 cells, induced to differentiate along the monocytic–macrophage pathway by TPA or vitamin D3, HTIF1α expression decreased, whereas it was maintained at high levels on induction to granulocytic differentiation by RA or DMSO. In K562 cells, HTIF1α RNA levels did not change after hemin-induced erythroid differentiation. These results suggest that HTIF1α could play a role in myeloid differentiation, being distinctly regulated in hematopoietic lineages
Scale-up studies for intensified production of biodiesel from used cooking oil
In this paper the effect of channel size on the transesterification of used cooking oil (UCO) with methanol using KOH as catalyst to produce biodiesel was investigated for capillaries with internal diameter ranging from 1 to 3 mm. A T-junction was used as the mixing zone of the two liquid phases. The effects of different parameters such as, internal diameter, methanol-to-oil molar ratio, reaction time, temperature, and catalyst concentration were investigated. Results showed that the conversion efficiency to biodiesel is increased by decreasing the channel size, whilst the interactions of the other variables are also discussed
Application of acoustic techniques to fluid-particle systems – A review
Acoustic methods applied to opaque systems have attracted the attention of researchers in fluid mechanics. In particular, owing to their ability to characterise in real-time, non-transparent and highly concentrated fluid-particle systems, they have been applied to the study of complex multiphase flows such as fluidised beds. This paper gives an overview of the physical principles and typical challenges of ultrasound and acoustic emission AE methods when applied to fluid-particle systems. The principles of ultrasound imaging are explained first. The measurement techniques and signal processing methodologies for obtaining velocity profiles, size distribution of the dispersed phases, and solid volume fraction are then discussed. The techniques are based on the measurement of attenuation, sound speed, frequency shift, and transit time of the propagated sound wave. A description of the acoustic emission technique and applications to fluid-particle systems are then discussed. Finally, extensions and future opportunities of the acoustic techniques are presented
- …