916,493 research outputs found
Proton spectra from Non-Mesonic Weak Decay of p-shell Lambda-Hypernuclei and evidence for the two-nucleon induced process
New spectra from the FINUDA experiment of the Non Mesonic Weak Decay (NMWD)
proton kinetic energy for 9(Lambda)Be, 11(Lambda)B, 12(Lambda)C, 13(Lambda)C,
15 (Lambda)N and 16(Lambda)O are presented and discussed along with the
published data on 5(Lambda)He and 7(Lambda)Li. Exploiting the large mass number
range and the low energy threshold (15 MeV) for the proton detection of FINUDA,
an evaluation of both Final State Interactions (FSI) and the two nucleon
induced NMWD contributions to the decay process has been done. Based on this
evaluation, a linear dependence of FSI on the hypernuclear mass number A is
found and for the two nucleon stimulated decay rate the experimental value of
Gamma2/Gammap=0.43+-0.25 is determined for the first time. A value for the two
nucleon stimulated decay rate to the total decay rate
Gamma2/GammaNMWD=0.24+-0.10 is also extracted.Comment: 11 pages and 2 figure
Relação da morte de ramos com a razão área foliar por fruto, crescimento vegetativo e produção em diferentes posições da copa do cafeeiro.
Neste trabalho, o objetivo foi avaliar a correlação entre a ?morte de ramos? e a razão área foliar por fruto, taxa de crescimento e produção de frutos em ramos de Coffea arabica L. cv. Catuaí Vermelho ? IAC 99, cultivado a campo. Para isso foram selecionadas 30 plantas de café cultivadas em renques orientados na posição norte-sul, e nelas selecionados 24 ramos com três razões de área foliar por fruto nas posições leste inferior, leste superior, oeste inferior e oeste superior da copa das plantas. O ensaio foi realizado na safra 2006-2007. Em cada posição foi realizado o acompanhamento do crescimento de ramos, da produção de frutos nos ramos e do número de ramos mortos. Foram estimadas as correlações entre a ?morte de ramos? e as variáveis: área foliar por fruto, taxa de crescimento dos ramos, produção total de frutos, produção de frutos normais e produção de frutos-bóia. Observou-se que, à medida que aumenta a razão da área foliar por fruto, ocorre aumento da taxa de crescimento de ramos, redução da produção de frutos-bóias e redução do número de ramos mortos
Convex Hull of Points Lying on Lines in o(n log n) Time after Preprocessing
Motivated by the desire to cope with data imprecision, we study methods for
taking advantage of preliminary information about point sets in order to speed
up the computation of certain structures associated with them.
In particular, we study the following problem: given a set L of n lines in
the plane, we wish to preprocess L such that later, upon receiving a set P of n
points, each of which lies on a distinct line of L, we can construct the convex
hull of P efficiently. We show that in quadratic time and space it is possible
to construct a data structure on L that enables us to compute the convex hull
of any such point set P in O(n alpha(n) log* n) expected time. If we further
assume that the points are "oblivious" with respect to the data structure, the
running time improves to O(n alpha(n)). The analysis applies almost verbatim
when L is a set of line-segments, and yields similar asymptotic bounds. We
present several extensions, including a trade-off between space and query time
and an output-sensitive algorithm. We also study the "dual problem" where we
show how to efficiently compute the (<= k)-level of n lines in the plane, each
of which lies on a distinct point (given in advance).
We complement our results by Omega(n log n) lower bounds under the algebraic
computation tree model for several related problems, including sorting a set of
points (according to, say, their x-order), each of which lies on a given line
known in advance. Therefore, the convex hull problem under our setting is
easier than sorting, contrary to the "standard" convex hull and sorting
problems, in which the two problems require Theta(n log n) steps in the worst
case (under the algebraic computation tree model).Comment: 26 pages, 5 figures, 1 appendix; a preliminary version appeared at
SoCG 201
Brotações epicórmicas no resgate vegetativo de indivíduos adultos de Eucalyptus spp.
O presente trabalho objetivou avaliar a indução de brotações epicórmicas em ramos destacados de cepas de Eucalyptus benthamii de 14 anos e Eucalyptus dunnii de 10 ano de idade. Os ramos destacados foram acondicionados em casa de vegetação, nos seguintes tratamentos T1=sobre a bancada, T2 = dentro de bandejas com água e T3= dentro de bandejas com areia fina. Foram avaliadas as características de sobrevivência e diâmetro do ápice dos ramos, número de tufos e número de brotos produzidos aos 45 e 90 dias. Para E.dunnii aos 45 dias os três tratamentos apresentaram sobrevivência de 100% para os ramos e o T2 foi o maior indutor de brotos; aos 90 dias o tratamento T2 também foi mais eficiente tanto na sobrevivência dos ramos quanto na produção de brotos. Para E. benthamii aos 45 dias o tratamento T1 apresentou maior sobrevivência dos ramos e o T3 foi o que mais produziu brotações e, aos 90 dias, houve mortalidade de 100% dos ramos. A técnica mostrou-se viável, com grandes variações entre os genótipos estudados, obtendo-se brotos com tamanho padrão para possível utilização em outras técnicas de propagação vegetativa, sendo E. dunnii a espécie que melhor se adaptou a este método de resgate.1 CD-ROM
First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of
continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a
fully coherent search, based on matched filtering, which uses the position and rotational parameters
obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto-
noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch
between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have
been developed, allowing a fully coherent search for gravitational waves from known pulsars over a
fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of
11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial
outliers, further studies show no significant evidence for the presence of a gravitational wave signal.
Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of
the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for
the first time. For an additional 3 targets, the median upper limit across the search bands is below the
spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried
out so far
A new combined approach to improved lipid production using a strictly aerobic and oleaginous yeast
Microbial lipids have potential applications in energy, and food industry, because most of those lipids are triacylglycerol with long-chain fatty-acids that are comparable to conventional vegetable oils and can be obtained without arable land requirement. Rhodosporidium toruloides is a strictly aerobic strain, where oxygen plays a crucial role in growth, maintenance, and metabolite production, such as lipids and carotenoids. Dissolved oxygen concentration is one of the major factors affecting yeast physiological and biochemical characteristics. In this context, different approaches have been developed to increase available oxygen by the increasing the aeration and the addition of an oxygen-vector. The growth of R. toruloides in 2-L mechanical stirred tank reactor equipped with 1 or 2 porous spargers and a 70 C/N ratio, revealed a lipid content of 0.47 and 0.52 g/g and a lipidic productivity of 0.16 and 0.17 g/L day, respectively. The oxygen-vector addition, increased the lipidic productivity for 0.20 g/L day and a lipid contend of 0.51 g of lipids/g of biomass. The combined approach, combining high aeration (AA), and 1% of n-dodecane addition (DA), produced a significant improvement in the lipid accumulation (62%, w/w), when compared with the DA (51%, w/w) and the AA (52%, w/w) approaches. The increasing of lipids accumulation and smaller culture time are key factors for the success of scale-up and profitability of a bioprocess.info:eu-repo/semantics/publishedVersio
Star formation in high-redshift quasars: excess [O II] emission in the radio-loud population
We investigate the [O II] emission line properties of 18,508 quasars at z<1.6
drawn from the Sloan Digital Sky Survey (SDSS) quasar sample. The quasar sample
has been separated into 1,692 radio-loud and 16,816 radio-quiet quasars (RLQs
and RQQs hereafter) matched in both redshift and i'-band absolute magnitude.
We use the [O II]\lambda3726+3729 line as an indicator of star formation.
Based on these measurements we find evidence that star-formation activity is
higher in the RLQ population. The mean equivalent widths (EW) for [O II] are
EW([O II])_RL=7.80\pm0.30 \AA, and EW([O II])_RQ=4.77\pm0.06 \AA, for the RLQ
and RQQ samples respectively. The mean [O II] luminosities are \log[L([O
II])_RL/W]=34.31\pm0.01 and \log[L([O II])_RQ/W]=34.192\pm0.004 for the samples
of RLQs and RQQs respectively. Finally, to overcome possible biases in the EW
measurements due to the continuum emission below the [O II] line being
contaminated by young stars in the host galaxy, we use the ratio of the [O II]
luminosity to rest-frame i'-band luminosity, in this case, we find for the RLQs
\log[L([O II])_RL/L_opt]=-3.89\pm0.01 and \log[L([O
II])_RQ/L_opt]=-4.011\pm0.004 for RQQs. However the results depend upon the
optical luminosity of the quasar. RLQs and RQQs with the same high optical
luminosity \log(L_opt/W)>38.6, tend to have the same level of [O II] emission.
On the other hand, at lower optical luminosities \log(L_opt/W)<38.6, there is a
clear [O II] emission excess for the RLQs. As an additional check of our
results we use the [O III] emission line as a tracer of the bolometric
accretion luminosity, instead of the i'-band absolute magnitude, and we obtain
similar results.
Radio jets appear to be the main reason for the [O II] emission excess in the
case of RLQs. In contrast, we suggest AGN feedback ensures that the two
populations acquire the same [O II] emission at higher optical luminosities.Comment: 12 pages, 9 figures, accepted for publication in MNRA
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