53,912 research outputs found
Compressibility effects on fluid entrainment by turbulent mixing layers
Compressibility effects on fluid entrainment by supersonic turbulent mixing layer
Conducting and integrating strategy research at the international, corporate, and business levels : issues and directions.
Word Embeddings for Entity-annotated Texts
Learned vector representations of words are useful tools for many information
retrieval and natural language processing tasks due to their ability to capture
lexical semantics. However, while many such tasks involve or even rely on named
entities as central components, popular word embedding models have so far
failed to include entities as first-class citizens. While it seems intuitive
that annotating named entities in the training corpus should result in more
intelligent word features for downstream tasks, performance issues arise when
popular embedding approaches are naively applied to entity annotated corpora.
Not only are the resulting entity embeddings less useful than expected, but one
also finds that the performance of the non-entity word embeddings degrades in
comparison to those trained on the raw, unannotated corpus. In this paper, we
investigate approaches to jointly train word and entity embeddings on a large
corpus with automatically annotated and linked entities. We discuss two
distinct approaches to the generation of such embeddings, namely the training
of state-of-the-art embeddings on raw-text and annotated versions of the
corpus, as well as node embeddings of a co-occurrence graph representation of
the annotated corpus. We compare the performance of annotated embeddings and
classical word embeddings on a variety of word similarity, analogy, and
clustering evaluation tasks, and investigate their performance in
entity-specific tasks. Our findings show that it takes more than training
popular word embedding models on an annotated corpus to create entity
embeddings with acceptable performance on common test cases. Based on these
results, we discuss how and when node embeddings of the co-occurrence graph
representation of the text can restore the performance.Comment: This paper is accepted in 41st European Conference on Information
Retrieva
Radiosensitizing and cytocidal effects on hypoxic cells of RO-07-0582, and repair of x-ray injury, in an experimental mouse tumour.
The delay in regrowth to 10 mm diameter of a transplanted carcinoma in mice was used to estimate the effect of the hypoxic-cell radiosensitizer Ro-07-0582. When 1 mg/g body wt. was given before a single dose of X-rays, a dose-enhancement ratio of 2-0 was found. When the drug was given immediately after irradiation, a large cytotoxic effect was observed, equivalent to an enhancement ratio of 1-3. These results were confirmed by determining the X-ray doses required for the local control of 50% of the tumours at 80 days after irradiation. The capacity of the tumour for repair of sublethal X-ray injury within 24 h was similar to that for several normal tissues
The weight for random quark masses
In theories in which the parameters of the low energy theory are not unique,
perhaps having different values in different domains of the universe as is
possible in some inflationary models, the fermion masses would be distributed
with respect to some weight. In such a situation the specifics of the fermion
masses do not have a unique explanation, yet the weight provides the visible
remnant of the structure of the underlying theory. This paper introduces this
concept of a weight for the distribution of masses and provides a quantitative
estimate of it from the observed quarks and leptons. The weight favors light
quark masses and appears roughly scale invariant (rho ~ 1/m). Some relevant
issues, such as the running of the weight with scale and the possible effects
of anthropic constraints, are also discussed.Comment: 35pages, 19 figure
Barrier formation at metal/organic interfaces: dipole formation and the Charge Neutrality Level
The barrier formation for metal/organic semiconductor interfaces is analyzed
within the Induced Density of Interface States (IDIS) model. Using weak
chemisorption theory, we calculate the induced density of states in the organic
energy gap and show that it is high enough to control the barrier formation. We
calculate the Charge Neutrality Levels of several organic molecules (PTCDA,
PTCBI and CBP) and the interface Fermi level for their contact with a Au(111)
surface. We find an excellent agreement with the experimental evidence and
conclude that the barrier formation is due to the charge transfer between the
metal and the states induced in the organic energy gap.Comment: 7 pages, Proceedings of ICFSI-9, Madrid, Spain (September 2003),
special issue of Applied Surface Science (in press
Hyperthermia Treatment of Experimental Tumors
The therapeutic advantage of combining hyperthermia with x-irradiation to treat tumors depends on whether or not it is possible to achieve greater thermal sensitization of tumors than of normal tissues. To determine such therapeutic gain factors (TGE), we assessed the response of mouse skin and seven transplantable mouse tumors to graded x-ray doses given alone or combined with moderate heat (42.5°C for 60 minutes). We constructed dose response curves for the average early skin reaction and for the induced delay in tumor regrowth to an arbitrarily chosen size. We studied the following areas: 1) the therapeutic gain of combining heat with x-irradiation; 2) irradiation and heat sequencing; 3) vascular occlusion; 4) temperature uniformity; 5) hyperthermia and metastatic spread; 6) fractionated treatment; and 7) thermal tolerance. Our results are not as promising as those of other published studies. We have shown that the time interval between heat and irradiation is important, and we believe that the separate cytotoxic action of heat and x-irradiation is likely to be more beneficial than the synergistic effect of combining the two in close sequence. We have also demonstrated the deficiencies of using hot water to achieve uniform heating, and the possible artefacts of vascular occlusion. We observed no significant effect on the spread of metastases when heat is used adjunctively with x-rays. We also induced thermal tolerance in a mouse tumor, which may account for the loss of therapeutic advantage seen with fractionated treatments
Calculation of Particle Production by Nambu Goldstone Bosons with Application to Inflation Reheating and Baryogenesis
A semiclassical calculation of particle production by a scalar field in a
potential is performed. We focus on the particular case of production of
fermions by a Nambu-Goldstone boson . We have derived a (non)local
equation of motion for the -field with the backreaction of the produced
particles taken into account. The equation is solved in some special cases,
namely for purely Nambu-Goldstone bosons and for the tilted potential . Enhanced production of bosons due to
parametric resonance is investigated; we argue that the resonance probably
disappears when the expansion of the universe is included. Application of our
work on particle production to reheating and an idea for baryogenesis in
inflation are mentioned.Comment: Submitted to Physical Review {\rm D}: October 4, 1994 21 page, UM-AC
94-3
- …