2,799 research outputs found
Degree Sequences and the Existence of -Factors
We consider sufficient conditions for a degree sequence to be forcibly
-factor graphical. We note that previous work on degrees and factors has
focused primarily on finding conditions for a degree sequence to be potentially
-factor graphical.
We first give a theorem for to be forcibly 1-factor graphical and, more
generally, forcibly graphical with deficiency at most . These
theorems are equal in strength to Chv\'atal's well-known hamiltonian theorem,
i.e., the best monotone degree condition for hamiltonicity. We then give an
equally strong theorem for to be forcibly 2-factor graphical.
Unfortunately, the number of nonredundant conditions that must be checked
increases significantly in moving from to , and we conjecture that
the number of nonredundant conditions in a best monotone theorem for a
-factor will increase superpolynomially in .
This suggests the desirability of finding a theorem for to be forcibly
-factor graphical whose algorithmic complexity grows more slowly. In the
final section, we present such a theorem for any , based on Tutte's
well-known factor theorem. While this theorem is not best monotone, we show
that it is nevertheless tight in a precise way, and give examples illustrating
this tightness.Comment: 19 page
Discovery of Two Relativistic Neutron Star-White Dwarf Binaries
We have discovered two recycled pulsars in relativistic orbits as part of the
first high-frequency survey of intermediate Galactic latitudes. PSR J1157-5112
is a 44 ms pulsar and the first recycled pulsar with an ultra-massive (M > 1.14
Mo) white dwarf companion. Millisecond pulsar J1757-5322 is a relativistic
circular-orbit system which will coalesce due to the emission of gravitational
radiation in less than 9.5 Gyr. Of the ~40 known circular orbit pulsars,
J1757-5322 and J1157-5112 have the highest projected orbital velocities. There
are now three local neutron-star/white-dwarf binaries that will coalesce in
less than a Hubble time, implying a large coalescence rate for these objects in
the local Universe. Systems such as J1141-6545 (Kaspi et al. 2000) are
potential gamma-ray burst progenitors and dominate the coalescence rate, whilst
lighter systems make excellent progenitors of millisecond pulsars with
planetary or ultra-low mass companions.Comment: 4 pages, to appear in ApJ Letters. Uses aastex v 5.0,
emulateapj5.sty, apjfonts.st
Towards the development of the psychosocial impact of assistive devices scale for continence (C-PIADS)
BACKGROUND: Current outcome measures for continence management devices do not adequately address psychosocial impact. The PIADS is an assessment tool that has been shown to reliably predict the adoption and use of assistive technology devices, but it is not widely used for continence devices. OBJECTIVE: To explore whether the PIADS requires modification to address the particular needs of continence device users and to inform any subsequent item development. METHODS: The study used interpretive methods in which qualitative information from semi-structured interviews was combined with the findings from cognitive interviews for questionnaire pre-testing. A total of 40 participants in UK and Canada were interviewed. RESULTS: Few participants had difficulty in understanding or relating to the majority of PIADS items. Several items were not considered relevant to continence and some areas for potential new items were uncovered. Embarrassment and concealment of urinary incontinence from others were common topics. CONCLUSIONS: The PIADS appears to fundamentally address many, but not all, of the important psychosocial concerns of adults who have continence difficulties. A version for continence, the C-PIADS, will require modification of the PIADS and is likely to contain some new items
The CLARIN Knowledge Centre for Atypical Communication Expertise
In this chapter we introduce the CLARIN Knowledge Centre for Atypical Communication Expertise. The mission of ACE is to support researchers engaged in languages which pose particular challenges for analysis; for this, we use the umbrella term “atypical communication”. This includes language use by second-language learners, people with language disorders or those suffering from lan-guage disabilities, and languages that pose unique challenges for analysis, such as sign languages and languages spoken in a multilingual context. The chapter presents details about the collaborations and outreach of the centre, the services offered, and a number of showcases for its activities
Catalytic Dibenzocyclooctene Synthesis via Cobalt(III)–Carbene Radical and <i>ortho</i>‐Quinodimethane Intermediates
Catalytic Dibenzocyclooctene Synthesis via Cobalt(III)–Carbene Radical and <i>ortho</i>‐Quinodimethane Intermediates
A Survey of Best Monotone Degree Conditions for Graph Properties
We survey sufficient degree conditions, for a variety of graph properties,
that are best possible in the same sense that Chvatal's well-known degree
condition for hamiltonicity is best possible.Comment: 25 page
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