177 research outputs found
The diffusion of IP telephony and vendors' commercialisation strategies
This is a post-peer-review, pre-copyedit version of an article published in the Journal of Information Technology. The definitive publisher-authenticated version is available at the link below.The Internet telephony (IP telephony) has been presented as a technology that can replace existing fixed-line services and disrupt the telecommunications industry by offering new low-priced services. This study investigates the diffusion of IP telephony in Denmark by focusing on vendorsâ commercialisation strategies. The theory of disruptive innovation is introduced to investigate vendorsâ perceptions about IP telephony and explore their strategies that affect the diffusion process in the residential market. The analysis is based on interview data collected from the key market players. The study's findings suggest that IP telephony is treated as a sustaining innovation that goes beyond the typical voice transmission and enables provision of advanced services such as video telephony
Inverting Onto Functions and Polynomial Hierarchy
In this paper we construct an oracle under which
the polynomial hierarchy is infinite but
there are non-invertible polynomial time computable multivalued onto functions
Effects of Nosema apis, N. ceranae, and coinfections on honey bee (Apis mellifera) learning and memory
Western honey bees (Apis mellifera) face an increasing number of challenges that in recent years have led to significant economic effects on apiculture, with attendant consequences for agriculture. Nosemosis is a fungal infection of honey bees caused by either Nosema apis or N. ceranae. The putative greater virulence of N. ceranae has spurred interest in understanding how it differs from N. apis. Little is known of effects of N. apis or N. ceranae on honey bee learning and memory. Following a Pavlovian model that relies on the proboscis extension reflex, we compared acquisition learning and long-term memory recall of uninfected (control) honey bees versus those inoculated with N. apis, N. ceranae, or both. We also tested whether spore intensity was associated with variation in learning and memory. Neither learning nor memory differed among treatments. There was no evidence of a relationship between spore intensity and learning, and only limited evidence of a negative effect on memory; this occurred only in the co-inoculation treatment. Our results suggest that if Nosema spp. are contributing to unusually high colony losses in recent years, the mechanism by which they may affect honey bees is probably not related to effects on learning or memory, at least as assessed by the proboscis extension reflex
Three Novel Pigmentation Mutants Generated by Genome-Wide Random ENU Mutagenesis in the Mouse
Three mutant mice with pigmentation phenotypes were recovered from a genomewide
random mouse chemical mutagenesis study. White toes (Whto; MGI:1861986),
Belly spot and white toes (Bswt; MGI:2152776) and Dark footpads 2 (Dfp2;
MGI:1861991) were identified following visual inspection of progeny from a male
exposed to the point mutagen ethylnitrosourea (ENU). In order to rapidly localize
the causative mutations, genome-wide linkage scans were performed on pooled
DNA samples from backcross animals for each mutant line. Whto was mapped to
proximal mouse chromosome (Mmu) 7 between Cen (the centromere) and D7Mit112
(8.0 cM from the centromere), Bswt was mapped to centric Mmul between D1Mit214
(32.1 cM) and D1Mit480 (32.8 cM) and Dfp2 was mapped to proximalMmu4 between
Cen and D4Mit18 (5.2 cM). Whto, Bswt and Dfp2 may provide novel starting
points in furthering the elucidation of genetic and biochemical pathways relevant
to pigmentation and associated biological processes
Level models of continuing professional development evaluation: a grounded review and critique
Continuing professional development (CPD) evaluation in education has been heavily influenced by âlevel modelsâ, deriving from the work of Kirkpatrick and Guskey in particular, which attempt to trace the processes through which CPD interventions achieve outcomes. This paper considers the strengths and limitations of such models, and in particular the degree to which they are able to do justice to the complexity of CPD and its effects. After placing level models within the broader context of debates about CPD evaluation, the paper reports our experience of developing such models heuristically for our own evaluation practice. It then draws on positivist, realist and constructivist traditions to consider some more fundamental ontological and epistemological questions to which they give rise. The paper concludes that level models can be used in a number of ways and with differing emphases, and that choices made about their use will need to reflect both theoretical choices and practical considerations
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Absolute luminosity measurements with the LHCb detector at the LHC
Absolute luminosity measurements are of general interest for colliding-beam
experiments at storage rings. These measurements are necessary to determine the
absolute cross-sections of reaction processes and are valuable to quantify the
performance of the accelerator. Using data taken in 2010, LHCb has applied two
methods to determine the absolute scale of its luminosity measurements for
proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In
addition to the classic "van der Meer scan" method a novel technique has been
developed which makes use of direct imaging of the individual beams using
beam-gas and beam-beam interactions. This beam imaging method is made possible
by the high resolution of the LHCb vertex detector and the close proximity of
the detector to the beams, and allows beam parameters such as positions, angles
and widths to be determined. The results of the two methods have comparable
precision and are in good agreement. Combining the two methods, an overall
precision of 3.5% in the absolute luminosity determination is reached. The
techniques used to transport the absolute luminosity calibration to the full
2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6,
9 and 10 and corresponding explanation in the tex
Absolute luminosity measurements with the LHCb detector at the LHC
Absolute luminosity measurements are of general interest for colliding-beam
experiments at storage rings. These measurements are necessary to determine the
absolute cross-sections of reaction processes and are valuable to quantify the
performance of the accelerator. Using data taken in 2010, LHCb has applied two
methods to determine the absolute scale of its luminosity measurements for
proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In
addition to the classic "van der Meer scan" method a novel technique has been
developed which makes use of direct imaging of the individual beams using
beam-gas and beam-beam interactions. This beam imaging method is made possible
by the high resolution of the LHCb vertex detector and the close proximity of
the detector to the beams, and allows beam parameters such as positions, angles
and widths to be determined. The results of the two methods have comparable
precision and are in good agreement. Combining the two methods, an overall
precision of 3.5% in the absolute luminosity determination is reached. The
techniques used to transport the absolute luminosity calibration to the full
2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6,
9 and 10 and corresponding explanation in the tex
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1
of pp collision data collected by the LHCb experiment at a centre-of-mass
energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 ->
phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the
first uncertainty is statistical, the second is the experimental systematic
uncertainty and the third is associated with the ratio of fragmentation
fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the
branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x
10^{-5}.
The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with
the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/-
0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the
previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table
- âŠ