3,648 research outputs found
Experimental search for anisotropic flux flow resistivity in the a-b plane of optimally doped epitaxial thin films of YBCO
Transport measurements along the node and anti-node directions in the a-b
plane of optimally doped and epitaxial thin films of YBCO are reported. Low
bias magnetoresistance measurements near and below T_c show that the flux flow
resistivity along the node and anti-node directions versus magnetic field are
indistinguishable. This result suggests that within the experimental error of
our measurements, no correspondence is found between the flux pinning
properties in YBCO and the d-wave nature of the order parameter.Comment: 5 figure
Conformative Filtering for Implicit Feedback Data
Implicit feedback is the simplest form of user feedback that can be used for
item recommendation. It is easy to collect and is domain independent. However,
there is a lack of negative examples. Previous work tackles this problem by
assuming that users are not interested or not as much interested in the
unconsumed items. Those assumptions are often severely violated since
non-consumption can be due to factors like unawareness or lack of resources.
Therefore, non-consumption by a user does not always mean disinterest or
irrelevance. In this paper, we propose a novel method called Conformative
Filtering (CoF) to address the issue. The motivating observation is that if
there is a large group of users who share the same taste and none of them have
consumed an item before, then it is likely that the item is not of interest to
the group. We perform multidimensional clustering on implicit feedback data
using hierarchical latent tree analysis (HLTA) to identify user `tastes' groups
and make recommendations for a user based on her memberships in the groups and
on the past behavior of the groups. Experiments on two real-world datasets from
different domains show that CoF has superior performance compared to several
common baselines
Isolation of high quality graphene from Ru by solution phase intercalation
2013 AIP Publishing LL
Post- and peritraumatic stress in disaster survivors: An explorative study about the influence of individual and event characteristics across different types of disasters
Background:
Examination of existing research on posttraumatic adjustment after disasters suggests that survivors’ posttraumatic stress levels might be better understood by investigating the influence of the characteristics of the event experienced on how people thought and felt, during the event as well as afterwards.
Objective:
To compare survivors’ perceived post- and peritraumatic emotional and cognitive reactions across different types of disasters. Additionally, to investigate individual and event characteristics.
Design:
In a European multi-centre study, 102 survivors of different disasters terror attack, flood, fire and collapse of a building were interviewed about their responses during the event. Survivors’ perceived posttraumatic stress levels were assessed with the Impact of Event Scale-Revised (IES-R). Peritraumatic emotional stress and risk perception were rated retrospectively. Influences of individual characteristics, such as socio-demographic data, and event characteristics, such as time and exposure factors, on post- and peritraumatic outcomes were analyzed.
Results:
Levels of reported post- and peritraumatic outcomes differed significantly between types of disasters. Type of disaster was a significant predictor of all three outcome variables but the factors gender, education, time since event, injuries and fatalities were only significant for certain outcomes.
Conclusion:
Results support the hypothesis that there are differences in perceived post- and peritraumatic emotional and cognitive reactions after experiencing different types of disasters. However, it should be noted that these findings were not only explained by the type of disaster itself but also by individual and event characteristics. As the study followed an explorative approach, further research paths are discussed to better understand the relationships between variables
YAP and β-catenin co-operate to drive oncogenesis in basal breast cancer
Targeting cancer stem cells (CSCs) can serve as an effective approach toward limiting resistance to therapies and the development of metastases in many forms of cancer. While basal breast cancers encompass cells with CSC features, rational therapies remain poorly established. Here, we show that receptor tyrosine kinase Met signalling promotes the activity of the Hippo component YAP in basal breast cancer. Further analysis revealed enhanced YAP activity within the CSC population. Using both genetic and pharmaceutical approaches, we show that interfering with YAP activity delays basal cancer formation, prevents luminal to basal trans-differentiation and reduces CSC survival. Gene expression analysis of YAP knock-out mammary glands revealed a strong decrease in β-catenin target genes in basal breast cancer, suggesting that YAP is required for nuclear β-catenin activity. Mechanistically, we find that nuclear YAP interacts and overlaps with β-catenin and TEAD4 at common gene regulatory elements. Analysis of proteomic data from primary breast cancer patients identified a significant upregulation of the YAP activity signature in basal compared to other breast cancers, suggesting that YAP activity is limited to basal types. Our findings demonstrate that in basal breast cancers, β-catenin activity is dependent on YAP signalling and controls the CSC program. These findings suggest that targeting the YAP/TEAD4/β-catenin complex offers a potential therapeutic strategy for eradicating CSCs in basal (triple-negative) breast cancers
Schumacher's quantum data compression as a quantum computation
An explicit algorithm for performing Schumacher's noiseless compression of
quantum bits is given. This algorithm is based on a combinatorial expression
for a particular bijection among binary strings. The algorithm, which adheres
to the rules of reversible programming, is expressed in a high-level pseudocode
language. It is implemented using two- and three-bit primitive
reversible operations, where is the length of the qubit strings to be
compressed. Also, the algorithm makes use of auxiliary qubits; however,
space-saving techniques based on those proposed by Bennett are developed which
reduce this workspace to while increasing the running time by
less than a factor of two.Comment: 37 pages, no figure
Current density inhomogeneity throughout the thickness of superconducting films and its effect on their irreversible magnetic properties
We calculate the distribution of the current density in superconducting
films along the direction of an external field applied perpendicular to the
film plane. Our analysis reveals that in the presence of bulk pinning is
inhomogeneous on a length scale of order the inter vortex distance. This
inhomogeneity is significantly enhanced in the presence of surface pinning. We
introduce new critical state model, which takes into account the current
density variations throughout the film thickness, and show how these variations
give rise to the experimentally observed thickness dependence of and
magnetic relaxation rate.Comment: RevTex, 9 PS figures. To appear in Phys. Rev.
The , interaction in finite volume and the nature of the resonance
An SU(4) extrapolation of the chiral unitary theory in coupled channels done
to study the scalar mesons in the charm sector is extended to produce results
in finite volume. The theory in the infinite volume produces dynamically the
resonance by means of the coupled channels , .
Energy levels in the finite box are evaluated and, assuming that they would
correspond to lattice results, the inverse problem of determining the bound
states and phase shifts in the infinite volume from the lattice data is
addressed. We observe that it is possible to obtain accurate phase shifts
and the position of the state, but it requires the explicit
consideration of the two coupled channels in the analysis if one goes close to
the threshold. We also show that the finite volume spectra look
rather different in case the is a composite state of the two
mesons, or if it corresponds to a non molecular state with a small overlap with
the two meson system. We then show that a careful analysis of the finite volume
data can shed some light on the nature of the resonance as a
molecule or otherwise.Comment: Published versio
Flux-flow resistivity anisotropy in the instability regime in the a-b plane of epitaxial YBCO thin films
Measurements of the nonlinear flux-flow resistivity and the critical
vortex velocity at high voltage bias close to the instability
regime predicted by Larkin and Ovchinnikov \cite{LO} are reported along the
node and antinode directions of the d-wave order parameter in the \textit{a-b}
plane of epitaxial films. In this pinning-free regime,
and are found to be anisotropic with values in the node
direction larger on average by 10% than in the antinode direction. The
anisotropy of is almost independent of temperature and field. We
attribute the observed results to the anisotropic quasiparticle distribution on
the Fermi surface of .Comment: 5 figure
- …