8,991 research outputs found
Modeling the input history of programs for improved instruction-memory performance
When a program is loaded into memory for execution, the relative position of
its basic blocks is crucial, since loading basic blocks that are unlikely to be
executed first places them high in the instruction-memory hierarchy only to be
dislodged as the execution goes on. In this paper we study the use of Bayesian
networks as models of the input history of a program. The main point is the
creation of a probabilistic model that persists as the program is run on
different inputs and at each new input refines its own parameters in order to
reflect the program's input history more accurately. As the model is thus
tuned, it causes basic blocks to be reordered so that, upon arrival of the next
input for execution, loading the basic blocks into memory automatically takes
into account the input history of the program. We report on extensive
experiments, whose results demonstrate the efficacy of the overall approach in
progressively lowering the execution times of a program on identical inputs
placed randomly in a sequence of varied inputs. We provide results on selected
SPEC CINT2000 programs and also evaluate our approach as compared to the gcc
level-3 optimization and to Pettis-Hansen reordering
Two-band superconductivity in doped SrTiO films and interfaces
We investigate the possibility of multi-band superconductivity in SrTiO
films and interfaces using a two-dimensional two-band model. In the undoped
compound, one of the bands is occupied whereas the other is empty. As the
chemical potential shifts due to doping by negative charge carriers or
application of an electric field, the second band becomes occupied, giving rise
to a strong enhancement of the transition temperature and a sharp feature in
the gap functions, which is manifested in the local density of states spectrum.
By comparing our results with tunneling experiments in Nb-doped SrTiO, we
find that intra-band pairing dominates over inter-band pairing, unlike other
known multi-band superconductors. Given the similarities with the value of the
transition temperature and with the band structure of LaAlO/SrTiO
heterostructures, we speculate that the superconductivity observed in
SrTiO interfaces may be similar in nature to that of bulk SrTiO,
involving multiple bands with distinct electronic occupations.Comment: revised expanded versio
The AGN properties of the starburst galaxy NGC 7582
NGC 7582 was identified as a Starburst galaxy in the optical \cite[(Veron et
al. 1981)]{Veron et al.(1981)} but its X-Ray emission is typical of a Seyfert 1
galaxy \cite[(Ward et al. 1978)]{Ward et al.(1978)}. We analyzed a datacube of
this object obtained with the GMOS-IFU on the Gemini-South telescope. After a
subtraction of the stellar component using the {\sc starlight} code \cite[(Cid
Fernandes et al. 2005)]{Cid Fernandes et al. (2005)}, we looked for optical
signatures of the AGN. We detected a broad component (figure
\ref{fig1}) in the source where \cite[Bianchi et al.(2007)]{Bianchi et
al.(2007)} identified the AGN in an HST optical image. We also found a broad
feature (figure \ref{fig2}), but its emission reveals a extended
source. We suggest that it is the light of the AGN scattered in the ionization
cone. We propose that NGC 7582 is a Seyfert 1 galaxy. A number of other
"hot-spots" and Wolf-Rayet features were also identified.Comment: 1 page, 2 figures, to be published in the Proceedings of the IAU
Symposium no. 26
Photodynamic therapy as adjunctive therapy for morpheaform basal cell carcinoma
The authors decided to evaluate the possible use of methyl-aminolevulinate photodynamic therapy
(MAL-PDT) as adjunctive therapy for morpheaform basal cell carcinoma prior to standard surgical
excision in order to reduce tumor size and volume and to facilitate surgical treatment. It was observed
that MAL-PDT may be an option as an adjunctive therapy prior to standard surgical excision of
morpheaform basal cell carcinoma, leading to less invasive surger
Tinea Capitis in Adults. A Diagnosis to Consider?
A tinea capitis, uma infecção por fungos dermatófitos do couro cabeludo, é uma patologia rara no adulto, mesmo em áreas geográficas onde a doença é prevalente. Nestes casos está muitas vezes, mas não exclusivamente, associada a imunodepressão e habitualmente surge por exposição ao agente infeccioso em contactantes próximos.
São fundamentais uma história clÃnica e um exame objectivo minuciosos que permitam equacionar a tinha do couro cabeludo como hipótese diagnóstica e proceder à colheita de amostras para exame micológico. Esta metodologia pode evitar a realização de exames complementares exaustivos ou a prescrição de tratamentos inadequados.
Os autores descrevem três casos de tinea capitis em mulheres adultas – dois casos de infecção por Microsporum audouinii e um caso por Trichophyton soudanense. É apresentado o registo iconográfico dos casos e é efectuada breve revisão da literatura
Conhecimento dos serviços da FCCN junto da comunidade cientÃfica e tecnológica nacional: um inquérito por questionário
O relatório aqui apresentado resulta de uma prestação de serviços, por parte de uma equipa do ISCTE-IUL,
à FCCN (Fundação para a Computação CientÃfica Nacional). Esta visou apoiar o lançamento de um inquérito
por questionário aos membros da comunidade cientÃfica e tecnológica nacional, com o fim de aferir a
perceção acerca dos serviços da FCCN, designadamente em termos de Conectividade, Computação,
Colaboração, Conhecimento e Segurança.info:eu-repo/semantics/publishedVersio
Post-activation performance enhancement in sprinters: effects of hard versus sand surfaces
Abstract This study aimed to compare the post-activation performance enhancement induced by successive drop-jumps performed on hard and sand surfaces in sprint and jump performance of top-level sprinters. Athletes were tested on two occasions. On each visit they were allocated to one of the experimental protocols, which consisted of performing 2x5 drop-jumps from a box with the height of 60-cm on hard or sand surfaces in randomized order, seven days apart. Prior to and 7 and 15-min after executing drop-jumps, sprinters performed countermovement jumps and 60-m sprint tests. Differences between sprinting splits and surfaces were assessed using a two-way analysis of variance with repeated measures. No significant differences in jump height or sprint time were observed (p>0.05), regardless of the surface used (i.e., hard or sand) during the conditioning activity (effect sizes [95% confidence intervals] ranging from 0.01 [-0.84;0.84] to 0.44 [-0.42;1.27]). Performing drop-jumps on sand or hard surfaces immediately before maximum sprinting bouts does not provide any advantage or disadvantage to top-level sprinters. Sprint coaches may prescribe short-plyometric training activities on sand surfaces even close to competitions, bearing in mind that this strategy will not compromise sprint-specific performance
Monte Carlo simulations of 2d hard core lattice gases
Monte Carlo simulations are used to study lattice gases of particles with
extended hard cores on a two dimensional square lattice. Exclusions of one and
up to five nearest neighbors (NN) are considered. These can be mapped onto hard
squares of varying side length, (in lattice units), tilted by some
angle with respect to the original lattice. In agreement with earlier studies,
the 1NN exclusion undergoes a continuous order-disorder transition in the Ising
universality class. Surprisingly, we find that the lattice gas with exclusions
of up to second nearest neighbors (2NN) also undergoes a continuous phase
transition in the Ising universality class, while the Landau-Lifshitz theory
predicts that this transition should be in the universality class of the XY
model with cubic anisotropy. The lattice gas of 3NN exclusions is found to
undergo a discontinuous order-disorder transition, in agreement with the
earlier transfer matrix calculations and the Landau-Lifshitz theory. On the
other hand, the gas of 4NN exclusions once again exhibits a continuous phase
transition in the Ising universality class -- contradicting the predictions of
the Landau-Lifshitz theory. Finally, the lattice gas of 5NN exclusions is found
to undergo a discontinuous phase transition.Comment: 13 pages, lots of figure
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