6,034 research outputs found
Computing Aggregate Properties of Preimages for 2D Cellular Automata
Computing properties of the set of precursors of a given configuration is a
common problem underlying many important questions about cellular automata.
Unfortunately, such computations quickly become intractable in dimension
greater than one. This paper presents an algorithm --- incremental aggregation
--- that can compute aggregate properties of the set of precursors
exponentially faster than na{\"i}ve approaches. The incremental aggregation
algorithm is demonstrated on two problems from the two-dimensional binary Game
of Life cellular automaton: precursor count distributions and higher-order mean
field theory coefficients. In both cases, incremental aggregation allows us to
obtain new results that were previously beyond reach
The influence of estrogen on nigrostriatal dopamine activity : Behavioral and neurochemical evidence for both pre- and postsynaptic components
The results of 3 experiments examining the influence of estrogen on the nigrostriatal dopamine (DA) system are reported. In two experiments the influence of hormonal manipulations on amphetamine (AMPH)-induced rotational behavior was investigated using rats with unilateral 6-hydroxydopamine lesions of the substantia nigra. It was found that: (1) female rats in estrus make more rotations than ovariectomized (OVX) rats; and (2) estrogen treatment (5 [mu]g estradiol benzoate, daily for 4 days) in OVX rats enhances AMPH-induced rotational behavior 4 h and 4 days after estrogen treatment. During the intervening period, at 24 h after cessation of estrogen treatment, control and hormone-treated animals did not differ. In a third experiment, the effect of estrogen treatment on the release of endogenous DA from striatal tissue slices in superfusion was examined. Estrogen enhanced AMPH-stimulated striatal DA release 4 h after the last treatment relative to OVX controls. However, 24 h and 4 days after estrogen treatment DA release had returned to control levels. It is suggested that estrogen has an immediate potentiating effect on striatal DA release, and this may be responsible for the increased behavioral response to AMPH 4 h after estrogen treatment. The previously demonstrated increase in postsynaptic striatal DA receptors may be responsible for the second increase in AMPH-induced rotational behavior, that occurs 4 days after estrogen treatment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26324/1/0000411.pd
Characterisation of Pinotage Wine During Maturation on Different Oak Products
The effect of oak contact on the phenolic composition, total antioxidant capacity (TAC) and colour of Pinotage wineswas investigated during maturation. Oak maturation included traditional treatments, such as new, second-fill andthird-fill barrels, as well as alternative treatments (oak chips, staves, extract and dust) applied in old barrels over aperiod of 28 weeks. Oak maturation using traditional and alternative treatments improved the objective colour ofPinotage wine by decreasing the L* value. Losses in TAC caused by decreased concentrations of monomeric phenoliccompounds (most anthocyanins, flavan-3-ols, flavonols and hydroxycinnamic acids) during oak maturation werenegated by increased concentrations of gallic acid and the formation of new oligomeric and polymeric pigments.Wine maturation in stainless steel containers also resulted in a decrease in anthocyanin content. The decreasein phenolic acid content for wines matured in stainless steel was less pronounced, while their flavan-3-ol contentremained stable. The new-barrel treatment had the most pronounced effect on all parameters. Oak maturation canbe used for the production of Pinotage wine when the retention of TAC is a high priority
Black Widow Pulsars: the Price of Promiscuity
The incidence of evaporating 'black widow' pulsars (BWPs) among all
millisecond pulsars (MSPs) is far higher in globular clusters than in the
field. This implies a special formation mechanism for them in clusters. Cluster
MSPs in wide binaries with WD companions exchange them for turnoff-mass stars.
These new companions eventually overflow their Roche lobes because of
encounters and tides. The millisecond pulsars eject the overflowing gas from
the binary, giving mass loss on the binary evolution timescale. The systems are
only observable as BWPs at epochs where this evolution is slow, making the mass
loss transparent and the lifetime long. This explains why observed BWPs have
low-mass companions. We suggest that at least some field BWPs were ejected from
globular clusters or entered the field population when the cluster itself was
disrupted.Comment: 6 pages, 2 figures, MNRAS in pres
P33. Expression of alpha v beta 3 integrin in patients with high and low grade glioma
Fuente Fuente, Carlos;Puig-Pey, J.;Buenaño Pastor, Manue
SPECTRAL DENSITY ESTIMATION OF STOCHASTIC PROCESSES UNDER MISSING DATA AND UNCERTAINTY QUANTIFICATION WITH BAYESIAN DEEP LEARNING
Stochastic processes are widely adopted in many domains to deal with problems which are stochastic in nature and involve strong nonlinearity, nonstationarity and uncertain system parameters. However, the uncertainties of spectral representation of the underlying stochastic processes have not been adequately acknowledged due to the data problems in practice, for instance, missing data. Therefore, this paper proposes a novel method for uncertainty quantification of spectral representation in the presence of missing data using Bayesian deep learning models. A range of missing levels are tested. An example in stochastic dynamics is employed for illustration
The changing patterns of group politics in Britain
Two interpretations of ways in which group politics in Britain have presented challenges to democracy are reviewed: neo-corporatism or pluralistic stagnation and the rise of single issue interest groups. The disappearance of the first paradigm created a political space for the second to emerge. A three-phase model of group activity is developed: a phase centred around production interests, followed by the development of broadly based 'other regarding' groups, succeeded by fragmented, inner directed groups focusing on particular interests. Explanations of the decay of corporatism are reviewed. Single issue group activity has increased as party membership has declined and is facilitated by changes in traditional media and the development of the internet. Such groups can overload the policy-making process and frustrate depoliticisation. Debates about the constitution and governance have largely ignored these issues and there is need for a debate
Prairie pothole marshes as traps for nitrogen and phosphorous in agricultural runoff
Water quality of drainage influents and the lone effluent at Eagle Lake marsh, Iowa, was studied for 4 years (1976-1979). Because of drought conditions, there was no effluent from the marsh in 1976, 1977, or 1978. In 1979, the marsh was effective at removing inorganic N, especially N03-N, from runoff water passing through. It had little impact on levels of inorganic-P, total-P, and Kjeldahl-N; it was a net exporter of soluble organic carbon
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