2,620 research outputs found
Stem cell factor (SCF) and c-kit in the ovine fetal testis in normal and nutrition perturbed pregnancies
Stem cell factor (SCF) and c-kit in the ovine fetal testis in normal and nutrition perturbed pregnancie
Transport Control in Low-Dimensional Spin-1/2 Heisenberg Systems
We analyze transport of local magnetization and develop schemes to control
transport behavior in finite spin-1/2 Heisenberg chains and spin-1/2 Heisenberg
two-leg ladders at zero temperature. By adjusting parameters in the
Hamiltonians, these quantum systems may show both integrable and chaotic
limits. We provide examples of chaotic systems leading to diffusive and to
ballistic transport. In addition, methods of coherent quantum control to induce
a transition from diffusive to ballistic transport are proposed.Comment: 8 pages, 5 figure
3C 295, a cluster and its cooling flow at z=0.46
We present ROSAT HRI data of the distant and X-ray luminous (L_x(bol)=2.6^
{+0.4}_{-0.2} 10^{45}erg/sec) cluster of galaxies 3C 295. We fit both a
one-dimensional and a two-dimensional isothermal beta-model to the data, the
latter one taking into account the effects of the point spread function (PSF).
For the error analysis of the parameters of the two-dimensional model we
introduce a Monte-Carlo technique. Applying a substructure analysis, by
subtracting a cluster model from the data, we find no evidence for a merger,
but we see a decrement in emission South-East of the center of the cluster,
which might be due to absorption. We confirm previous results by Henry &
Henriksen(1986) that 3C 295 hosts a cooling flow. The equations for the simple
and idealized cooling flow analysis presented here are solely based on the
isothermal beta-model, which fits the data very well, including the center of
the cluster. We determine a cooling flow radius of 60-120kpc and mass accretion
rates of dot{M}=400-900 Msun/y, depending on the applied model and temperature
profile. We also investigate the effects of the ROSAT PSF on our estimate of
dot{M}, which tends to lead to a small overestimate of this quantity if not
taken into account. This increase of dot{M} (10-25%) can be explained by a
shallower gravitational potential inferred by the broader overall profile
caused by the PSF, which diminishes the efficiency of mass accretion. We also
determine the total mass of the cluster using the hydrostatic approach. At a
radius of 2.1 Mpc, we estimate the total mass of the cluster (M{tot}) to be
(9.2 +/- 2.7) 10^{14}Msun. For the gas to total mass ratio we get M{gas}/M{tot}
=0.17-0.31, in very good agreement with the results for other clusters of
galaxies, giving strong evidence for a low density universe.Comment: 26 pages, 7 figures, accepted for publication in Ap
Living for the weekend: youth identities in northeast England
Consumption and consumerism are now accepted as key contexts for the construction of youth identities in de-industrialized Britain. This article uses empirical evidence from interviews with young people to suggest that claims of `new community' are overstated, traditional forms of friendship are receding, and increasingly atomized and instrumental youth identities are now being culturally constituted and reproduced by the pressures and anxieties created by enforced adaptation to consumer capitalism. Analysis of the data opens up the possibility of a critical rather than a celebratory exploration of the wider theoretical implications of this process
Anti-Nirvana: crime, culture and instrumentalism in the age of insecurity
âAnti-Nirvanaâ explores the relationship between consumer culture, media and criminal motivations. It has appeared consistently on the list of the top-ten most-read articles in this award-winning international journal, and it mounts a serious neo-Freudian challenge to the predominant naturalistic notion of âresistanceâ at the heart of liberal criminology and media studies. It is also cited in the Oxford Handbook of Criminology and other criminology texts as a persuasive argument in support of the theory that criminality amongst young people is strongly linked to the acquisitive values of consumerism and the images of possessive individualism that dominate mass media
Manipulation of the dynamics of many-body systems via quantum control methods
We investigate how dynamical decoupling methods may be used to manipulate the
time evolution of quantum many-body systems. These methods consist of sequences
of external control operations designed to induce a desired dynamics. The
systems considered for the analysis are one-dimensional spin-1/2 models, which,
according to the parameters of the Hamiltonian, may be in the integrable or
non-integrable limits, and in the gapped or gapless phases. We show that an
appropriate control sequence may lead a chaotic chain to evolve as an
integrable chain and a system in the gapless phase to behave as a system in the
gapped phase. A key ingredient for the control schemes developed here is the
possibility to use, in the same sequence, different time intervals between
control operations.Comment: 10 pages, 3 figure
Studies on X-ray Thomson Scattering from Antiferroquadrupolar Order in TmTe
We study Thomson scattering from the antiferroquadrupole ordering phase in
TmTe. On the basis of the group theoretical treatment, we classify the
selection rules of the scattering intensity governed by the orientation of the
scattering vector G. Then, numerical verification is performed by invoking the
ground states which are deduced from a J=7/2 multiplet model. The obtained
intensity varies drastically depending on the magnitude and direction of G. We
also calculate the scattering intensities under the applied field for H//(001)
and (110). Their results behave differently when the orientation of G is
changed, which is ascribed to the difference of their primary order parameters;
O_{2}^{0} and O_{2}^{2} for H // (001) and (110), respectively. We make
critical comparisons between our results for TmTe and the experimental ones for
CeB_6. First, we assert that the intensities expected from TmTe at several
forbidden Bragg spots are sufficient enough to be experimentally detected.
Second, their intensities at (7/2,1/2,1/2) differ significantly and may be
attributed to the difference of the order parametersbetween the \Gamma_3-type
(O_{2}^{2} and O_{2}^{0}) and \Gamma_5-type (O_{yz}, O_{zx}, and O_{xy})
components, respectively.Comment: 18 pages, 3 figures, to be published in J. Phys. Soc. Jp
The future of enterprise groupware applications
This paper provides a review of groupware technology and products. The purpose of this review is to investigate the appropriateness of current groupware technology as the basis for future enterprise systems and evaluate its role in realising, the currently emerging, Virtual Enterprise model for business organisation. It also identifies in which way current technological phenomena will transform groupware technology and will drive the development of the enterprise systems of the future
TeCNO: Surgical Phase Recognition with Multi-Stage Temporal Convolutional Networks
Automatic surgical phase recognition is a challenging and crucial task with
the potential to improve patient safety and become an integral part of
intra-operative decision-support systems. In this paper, we propose, for the
first time in workflow analysis, a Multi-Stage Temporal Convolutional Network
(MS-TCN) that performs hierarchical prediction refinement for surgical phase
recognition. Causal, dilated convolutions allow for a large receptive field and
online inference with smooth predictions even during ambiguous transitions. Our
method is thoroughly evaluated on two datasets of laparoscopic cholecystectomy
videos with and without the use of additional surgical tool information.
Outperforming various state-of-the-art LSTM approaches, we verify the
suitability of the proposed causal MS-TCN for surgical phase recognition.Comment: 10 pages, 2 figure
Distinct Binding and Immunogenic Properties of the Gonococcal Homologue of Meningococcal Factor H Binding Protein
Neisseria meningitidis is a leading cause of sepsis and meningitis. The bacterium recruits factor H (fH), a negative regulator of the complement system, to its surface via fH binding protein (fHbp), providing a mechanism to avoid complement-mediated killing. fHbp is an important antigen that elicits protective immunity against the meningococcus and has been divided into three different variant groups, V1, V2 and V3, or families A and B. However, immunisation with fHbp V1 does not result in cross-protection against V2 and V3 and vice versa. Furthermore, high affinity binding of fH could impair immune responses against fHbp. Here, we investigate a homologue of fHbp in Neisseria gonorrhoeae, designated as Gonococcal homologue of fHbp (Ghfp) which we show is a promising vaccine candidate for N. meningitidis. We demonstrate that Gfhp is not expressed on the surface of the gonococcus and, despite its high level of identity with fHbp, does not bind fH. Substitution of only two amino acids in Ghfp is sufficient to confer fH binding, while the corresponding residues in V3 fHbp are essential for high affinity fH binding. Furthermore, immune responses against Ghfp recognise V1, V2 and V3 fHbps expressed by a range of clinical isolates, and have serum bactericidal activity against N. meningitidis expressing fHbps from all variant groups
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