12,853 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
The evolution of the Sun's birth cluster and the search for the solar siblings with Gaia
We use self-consistent numerical simulations of the evolution and disruption
of the Sun's birth cluster in the Milky Way potential to investigate the
present-day phase space distribution of the Sun's siblings. The simulations
include the gravitational N-body forces within the cluster and the effects of
stellar evolution on the cluster population. In addition the gravitational
forces due to the Milky Way potential are accounted for in a self-consistent
manner. Our aim is to understand how the astrometric and radial velocity data
from the Gaia mission can be used to pre-select solar sibling candidates. We
vary the initial conditions of the Sun's birth cluster, as well as the
parameters of the Galactic potential. We show that the disruption time-scales
of the cluster are insensitive to the details of the non-axisymmetric
components of the Milky Way model and we make predictions, averaged over the
different simulated possibilities, about the number of solar siblings that
should appear in surveys such as Gaia or GALAH. We find a large variety of
present-day phase space distributions of solar siblings, which depend on the
cluster initial conditions and the Milky Way model parameters. We show that
nevertheless robust predictions can be made about the location of the solar
siblings in the space of parallaxes (), proper motions () and
radial velocities (). By calculating the ratio of the number of
simulated solar siblings to that of the number of stars in a model Galactic
disk, we find that this ratio is above 0.5 in the region given by: mas, masyr, and kms. Selecting stars from this region should increase the probability
of success in identifying solar siblings through follow up observations
[Abridged].Comment: 13 pages, 7 figures. Accepted for publication in MNRA
Intensificação da bovinocultura de corte: estratégias de manejo reprodutivo e sanitário.
Manejo reprodutivo em gado de corte; Sincronizacao do estro em bovinos; Manejo sanitario em sistemas intensivos de producao de carne; Novos metodos de avaliacao da capacidade reprodutiva de touros.bitstream/CPPSE/12479/1/PROCIDoc26RTB636.0824LV.pd
Análise genética do período de gestação em animais de um rebanho Canchim: estimação de parâmetros genéticos e escolha entre modelos animais alternativos.
Os objetivos neste trabalho foram comparar modelos animais alternativos para a análise do período de gestação e verificar se essa característica possui variabilidade genética suficiente para ser incluída em programas de seleção, por meio de estimativas de herdabilidade e de correlações genéticas com os pesos ao nascimento (PN) e aos 12 meses de idade (P12), para animais de um rebanho Canchim. Foram analisadas gestações de 2.889 bezerros, 8.506 medidas de peso ao nascimento e 6.372 de peso aos 12 meses de idade. O período de gestação foi estudado como característica do bezerro (PGB) e da vaca (PGV). Os parâmetros genéticos foram estimados pela máxima verossimilhança restrita (REML). Quatro modelos animais alternativos foram testados em análises unicaracterísticas de PGB e de PGV, considerando-se efeitos fixos e combinações de três efeitos leatórios. O teste de razão de verossimilhança foi utilizado para comparação dos modelos. Análises bicaracterísticas foram feitas de PGB com peso ao nascimento e peso aos 12 meses de idade. As herdabilidades diretas de PGB variaram de 0,22 a 0,41 e as de PGV de 0,04 a 0,07. A correlação genética entre PGB e peso ao nascimento foi de 0,65 e entre PGB e P12 de 0,01. Conclui-se que o período de gestação deve ser estudado como característica do bezerro. O modelo que inclui apenas efeitos aleatórios aditivo direto e de ambiente permanente materno pode ser utilizado para análise genética desta característica e esta característica pode ser utilizada como critério de seleção
Hydration and anomalous solubility of the Bell-Lavis model as solvent
We address the investigation of the solvation properties of the minimal
orientational model for water, originally proposed by Bell and Lavis. The model
presents two liquid phases separated by a critical line. The difference between
the two phases is the presence of structure in the liquid of lower density,
described through orientational order of particles. We have considered the
effect of small inert solute on the solvent thermodynamic phases. Solute
stabilizes the structure of solvent, by the organization of solvent particles
around solute particles, at low temperatures. Thus, even at very high
densities, the solution presents clusters of structured water particles
surrounding solute inert particles, in a region in which pure solvent would be
free of structure. Solute intercalates with solvent, a feature which has been
suggested by experimental and atomistic simulation data. Examination of solute
solubility has yielded a minimum in that property, which may be associated with
the minimum found for noble gases. We have obtained a line of minimum
solubility (TmS) across the phase diagram, accompanying the line of maximum in
density (TMD). This coincidence is easily explained for non-interacting solute
and it is in agreement with earlier results in the literature. We give a simple
argument which suggests that interacting solute would dislocate TmS to higher
temperatures
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