355 research outputs found
Domain growth of Dy2O3 buffer layers on SrTiO3
Dy2O3 layers have been grown on SrTiO3 by molecular beam epitaxy. X-ray and electron diffraction patterns clearly show that Dy2O3 grows epitaxially on SrTiO3 with {100} planes parallel to the substrate surface. Transmission electron microscopy reveals that the Dy2O3 film breaks up into small domains (10-40 nm). This leads to the formation of terraces which limits the structural perfection of thin overgrown DyBa2Cu3O7 by introducing steps and small misorientations (within 3°). The resulting surface corrugation does not preclude the growth of epitaxial c-axis DyBa2Cu3O7 films with a Tc0 of 86 K. Crystallographic analysis and image calculations show that the domain growth of Dy2O3 is associated with the formation of 90° rotation twin
Language in a world of plurality:the tree, the bot and the octopus teacher
Abstract. Language has been considered proof of human exceptionalism in the Western European culture since the Enlightenment era. As a result, a rigid hierarchy placing human on the top emerged. Due to human’s capacity to rationalize thought and materialize it using language as a tool, it entitled itself to possess and dispose of anything deemed as less- or non-human.
Once the fixed idea of language is destabilized, its accuracy as a tool fit enough to represent the world and human thought comes into question. Once language, a pillar of Humanism, is damaged, the collapse of human exceptionalism is imminent.
Post-humanism and ontological pluralism are offering the grounds for exploring a paradigm without the hierarchy. A flattened reality in which the relationships between ways of being are far more complex than mere hierarchies, food chains, or concentric circles. They are entangled, mangled. They are plugging-in and unplugging in an assemblage.
For inquiring into an assemblage, tools such as qualitative methodologies, representational logic and data become useless. Meanwhile, post-qualitative inquiries do not pretend to ascend the ultimate, pure knowledge or truth but simply offer a brief, incomplete glimpse into the assemblage.
The results of such destabilizations consist of more care and attention being offered to negotiating language and languaging, empty spaces and howls, communication outside the higher senses of sight and hearing. In education, it translates into alternative teachers and teachings. The learners are entangled into an assemblage with which they are inter-acting by forming relationships. They are learning to co-live with rather than to make sense of the ways of being
Plane augmentation of plane graphs to meet parity constraints
A plane topological graph G=(V, E) is a graph drawn in the plane whose vertices are points in the plane and whose edges are simple curves that do not intersect, except at their endpoints. Given a plane topological graph G=(V, E) and a set CG of parity constraints, in which every vertex has assigned a parity constraint on its degree, either even or odd, we say that G is topologically augmentable to meet CG if there exists a set E' of new edges, disjoint with E, such that G'=(V, EÂżE') is noncrossing and meets all parity constraints. In this paper, we prove that the problem of deciding if a plane topological graph is topologically augmentable to meet parity constraints is NP-complete, even if the set of vertices that must change their parities is V or the set of vertices with odd degree. In particular, deciding if a plane topological graph can be augmented to a Eulerian plane topological graph is NP-complete. Analogous complexity results are obtained, when the augmentation must be done by a plane topological perfect matching between the vertices not meeting their parities. We extend these hardness results to planar graphs, when the augmented graph must be planar, and to plane geometric graphs (plane topological graphs whose edges are straight-line segments). In addition, when it is required that the augmentation is made by a plane geometric perfect matching between the vertices not meeting their parities, we also prove that this augmentation problem is NP-complete for plane geometric paths. For the particular family of maximal outerplane graphs, we characterize maximal outerplane graphs that are topological augmentable to satisfy a set of parity constraints. We also provide a polynomial time algorithm that decides if a maximal outerplane graph is topologically augmentable to meet parity constraints, and if so, produces a set of edges with minimum cardinality
On Optimal Coverage of a Tree with Multiple Robots
We study the algorithmic problem of optimally covering a tree with mobile
robots. The tree is known to all robots, and our goal is to assign a walk to
each robot in such a way that the union of these walks covers the whole tree.
We assume that the edges have the same length, and that traveling along an edge
takes a unit of time. Two objective functions are considered: the cover time
and the cover length. The cover time is the maximum time a robot needs to
finish its assigned walk and the cover length is the sum of the lengths of all
the walks. We also consider a variant in which the robots must rendezvous
periodically at the same vertex in at most a certain number of moves. We show
that the problem is different for the two cost functions. For the cover time
minimization problem, we prove that the problem is NP-hard when is part of
the input, regardless of whether periodic rendezvous are required or not. For
the cover length minimization problem, we show that it can be solved in
polynomial time when periodic rendezvous are not required, and it is NP-hard
otherwise
Cystoadaptometry in children with nephrolithiasis
In view of studying the function of the urinary bladder, at thirty nine children with ages between four and fifteen years old, diagnosed with
urotiliasis, 39 (thirty nine) cystoadaptomerys were performed and in about 60% (sixty percent) of the cases bladder hypotony was found. In order to
improve the treatment of the bladder hypotony, stimulant drugs of the urinary tract peristalsis, such as Neostigmina, Cerucal, Neiromedina, were added
to the treatment, which showed satisfying results
Different partial volume correction methods lead to different conclusions: An 18F-FDG-PET study of aging.
A cross-sectional group study of the effects of aging on brain metabolism as measured with 18F-FDG-PET was performed using several different partial volume correction (PVC) methods: no correction (NoPVC), Meltzer (MZ), Müller-Gärtner (MG), and the symmetric geometric transfer matrix (SGTM) using 99 subjects aged 65-87years from the Harvard Aging Brain study. Sensitivity to parameter selection was tested for MZ and MG. The various methods and parameter settings resulted in an extremely wide range of conclusions as to the effects of age on metabolism, from almost no changes to virtually all of cortical regions showing a decrease with age. Simulations showed that NoPVC had significant bias that made the age effect on metabolism appear to be much larger and more significant than it is. MZ was found to be the same as NoPVC for liberal brain masks; for conservative brain masks, MZ showed few areas correlated with age. MG and SGTM were found to be similar; however, MG was sensitive to a thresholding parameter that can result in data loss. CSF uptake was surprisingly high at about 15% of that in gray matter. The exclusion of CSF from SGTM and MG models, which is almost universally done, caused a substantial loss in the power to detect age-related changes. This diversity of results reflects the literature on the metabolism of aging and suggests that extreme care should be taken when applying PVC or interpreting results that have been corrected for partial volume effects. Using the SGTM, significant age-related changes of about 7% per decade were found in frontal and cingulate cortices as well as primary visual and insular cortices
Strong Pinning in High Temperature Superconductors
Detailed measurements of the critical current density jc of YBa2Cu3O7 films
grown by pulsed laser deposition reveal the increase of jc as function of the
filmthickness. Both this thickness dependence and the field dependence of the
critical current are consistently described using a generalization of the
theory of strong pinning of Ovchinnikov and Ivlev [Phys. Rev. B 43, 8024
(1991)]. From the model, we deduce values of the defect density (10^21 m^-3)
and the elementary pinning force, which are in good agreement with the
generally accepted values for Y2O3-inclusions. In the absence of clear evidence
that the critical current is determined by linear defects or modulations of the
film thickness, our model provides an alternative explanation for the rather
universal field dependence of the critical current density found in YBa2Cu3O7
films deposited by different methods.Comment: 11 pages; 8 Figures; Published Phys. Rev. B 66, 024523 (2002
Bioengineering bacterial encapsulin nanocompartments as targeted drug delivery system
The development of Drug Delivery Systems (DDS) has led to increasingly efficient therapies for the treatment and detection of various diseases. DDS use a range of nanoscale delivery platforms produced from polymeric of inorganic materials, such as micelles, and metal and polymeric nanoparticles, but their variant chemical composition make alterations to their size, shape, or structures inherently complex. Genetically encoded protein nanocages are highly promising DDS candidates because of their modular composition, ease of recombinant production in a range of hosts, control over assembly and loading of cargo molecules and biodegradability. One example of naturally occurring nanocompartments are encapsulins, recently discovered bacterial organelles that have been shown to be reprogrammable as nanobioreactors and vaccine candidates. Here we report the design and application of a targeted DDS platform based on the Thermotoga maritima encapsulin reprogrammed to display an antibody mimic protein called Designed Ankyrin repeat protein (DARPin) on the outer surface and to encapsulate a cytotoxic payload. The DARPin9.29 chosen in this study specifically binds to human epidermal growth factor receptor 2 (HER2) on breast cancer cells, as demonstrated in an in vitro cell culture model. The encapsulin-based DDS is assembled in one step in vivo by co-expressing the encapsulin-DARPin9.29 fusion protein with an engineered flavin-binding protein mini-singlet oxygen generator (MiniSOG), from a single plasmid in Escherichia coli. Purified encapsulin-DARPin_miniSOG nanocompartments bind specifically to HER2 positive breast cancer cells and trigger apoptosis, indicating that the system is functional and specific. The DDS is modular and has the potential to form the basis of a multi-receptor targeted system by utilising the DARPin screening libraries, allowing use of new DARPins of known specificities, and through the proven flexibility of the encapsulin cargo loading mechanism, allowing selection of cargo proteins of choice
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