73 research outputs found
Availability-Guaranteed Service Function Chain Provisioning with Optional Shared Backups
The dynamic provisioning of Service Function Chain (SFC) using Virtual Network Functions (VNFs) is a challenging problem, especially for availability-constrained services. The provisioning of backup resources is often used to ensure that availability requirements are fulfilled. However, the assignment of backup resources should be carefully designed to avoid resource inefficiencies as much as possible.This paper proposes the Optional Backup with Shared Path and Shared Function (OBSPSF) strategy, which aims at improving resource efficiency while fulfilling the availability requirements of SFC requests. The strategy uses optional backup provisioning to ensure that backup resources are assigned only when strictly needed (i.e., when the SFC alone does not meet the availability constraint). Moreover, OBSPSF encourages backup sharing (among both connectivity and backup VNFs) to reduce the backup resource overhead. Results show that the strategy can accommodate orders-of-magnitude more services than benchmark heuristics from the literature
ENRAIZAMENTO DE MINIESTACAS E PRODUTIVIDADE DE MINICEPAS DE CEDRO AUSTRALIANO MANEJADAS EM CANALET 5ES E TUBETES
The planted forest stands aim to supply the growing demand for wood,
especially for the sawing and veneer industries, that exclusively used
wood from native forests. The Australian cedar ( Toona ciliata )
belongs to the family Meliaceae, is the species of interest for this
sector. Studies with the Australian cedar propagation have carried out
in latest years, mainly involving the use of mini-cuttings due to the
need for high quality cuttings. The objectives of this paper were to
evaluate the rooting and the productive capacity of Australian cedar
mini-strains, managed in lifted seedbeds and 180 cm3 plastic tubes
systems. So, two mini-clone gardens were set up. The mini-strains of
both gardens were grown from cut-off seedlings originated from seeds.
Successive collections of sprouts were carried out to get the
mini-cuttings. Afterwards, they remained in the rooting area under
intermittent mist. Thirty days later the rooting characteristics of the
cuttings originated from both mini-gardens were evaluated. The period
of permanence of the cuttings in the gardens was seven-month long.
During this period, six collections from the lifted seedbed and four
from the plastic tubes were carried out. The mini-strains in the two
systems showed 100 % of survival rate. At the end of this seven-month
period, an increasing tendency of the average number of mini-cutting
was found out in both systems. Those from the lifted seedbed showed
more productivity than those ones from the tubes. The plants from the
mini-cuttings of the tube showed higher number and length of
adventitious roots at the end rooting stage.Os povoamentos florestais plantados buscam atender \ue0 demanda
crescente por madeira, principalmente, para as ind\ufastrias de
serraria e de lamina\ue7\ue3o, que utilizavam madeira
exclusivamente de matas nativas. O cedro australiano ( Toona ciliata
), pertencente \ue0 fam\uedlia Meliaceae, \ue9 uma das
esp\ue9cies de interesse desse setor. Pela necessidade cada vez maior
por mudas de alta qualidade, estudos sobre propaga\ue7\ue3o de
cedro australiano t\ueam sido realizados nos \ufaltimos anos,
principalmente envolvendo o uso da miniestaquia. Os objetivos deste
trabalho foram avaliar o enraizamento e a capacidade produtiva das
minicepas de cedro australiano, manejadas em sistemas de
canalet\uf5es e em tubetes de 180 cm3. Assim, estabeleceram-se dois
minijardins de minicepas formadas a partir de mudas recepadas,
produzidas por sementes. Nestes dois sistemas, foram realizadas coletas
sucessivas de brota\ue7\uf5es para confec\ue7\ue3o de
miniestacas, que permaneceram por 30 dias no setor de enraizamento, em
c\ue2mara com nebuliza\ue7\ue3o intermitente. Ap\uf3s este
per\uedodo, foram avaliadas as caracter\uedsticas do enraizamento
das mudas originadas nos dois sistemas de minijardins testados, que
foram conduzidos por sete meses e, durante este per\uedodo, foram
realizadas seis coletas no minijardim de canalet\ue3o e quatro, no de
tubetes. As minicepas dos dois sistemas apresentam 100 % de
sobreviv\ueancia. Ao final do per\uedodo observou-se tend\ueancia
no aumento do n\ufamero m\ue9dio de miniestacas em ambos os
sistemas. As minicepas do sistema de minijardim em canalet\ue3o
s\ue3o mais produtivas que as do sistema conduzido em tubetes. As
mudas originadas de miniestacas do sistema de tubetes apresentam maior
n\ufamero e comprimento de ra\uedzes advent\uedcias na
expedi\ue7\ue3o do setor de enraizamento
Morphometric characterization of fruits and seeds and the effect of the temperature on germination of Parkia pendula (Willd.) Benth. ex Walp
Parkia pendula (Willd.) Benth. ex Walp., \ue9 uma esp\ue9cie
arb\uf3rea, caracter\uedstica dos est\ue1dios iniciais da
sucess\ue3o, de ocorr\ueancia natural no Brasil. Pertence \ue0
fam\uedlia Fabaceae, com grande potencial na recupera\ue7\ue3o de
\ue1reas degradadas. O presente trabalho foi conduzido no Centro de
Ci\ueancias Agr\ue1rias da Universidade Federal de Alagoas,
objetivando a caracteriza\ue7\ue3o morfom\ue9trica de frutos e
sementes dessa esp\ue9cie, bem como identificar a melhor temperatura
para uso em testes de germina\ue7\ue3o. O fruto \ue9 do tipo
legume, deiscente, polisp\ue9rmico, contendo em m\ue9dia 16
sementes por unidade. Estas apresentam formato elipsoidal, embri\ue3o
axial, com 10,1 mm de comprimento, 4,9 mm de largura por 3,1mm de
espessura. As temperaturas de 25 e 30oC proporcionaram as maiores
porcentagem e velocidade de germina\ue7\ue3o, enquanto que a
temperatura de 15oC e acima de 35\ubaC influenciaram negativamente a
germinabilidade das sementes.Parkia pendula (Willd.) Benth. ex Walp. is a tree species,
characteristic of the initial phases of succession, of natural
occurrence in Brazil. It belongs to the Mimosaceae family, with great
potential in the recovery of degraded areas. The present work aims to
characterize fruits and seeds morphometrically as well to identify the
best temperature for use in germination test. The fruit is a type of
legume, dehiscent, polispermic, with 16 seeds, approximately, per unit.
The seeds present ellipsoidal format, axial embryo, with 10,1 mm of
length, 4,9 mm of width and 3,1 mm of thickness. The temperatures of
25\ubaC and 30\ubaC provided them larger germinability, while the
temperature of 15\ubaC and above 35\ubaC influenced these
characteristics negatively
Evaluating kinetic and physiological features of rCHO-K1 cells cultured on microcarriers for production of a recombinant metalloprotease/disintegrin
We present kinetic and physiological data regarding the culturing of
rCHO-K1 cells on various microcarriers, to evaluate the potential of
this culture strategy for mass production of these cells and expression
of a recombinant disintegrin. Cultures were performed in 500 mL spinner
flasks in DMEM culture medium with 10% v/v fetal calf serum, gently
shaken at 37\ub0C, pH 7.4, in a 10% v/v CO2 atmosphere. The following
values were obtained, respectively, for the adhesion time-constant Ka
(h) and specific growth rate \u3bcmax (d-1) on each microcarrier:
Cytodex 1 (0.91, 0.45), Cultispher S (0.28, 0.34), Immobasil FS (0.85,
0.52) and Pronectin F (5.12, 0.67). Metabolic characteristics showed
some variation among the cultures with the four microcarriers, the most
significant being the higher production of ammonia with microcarriers
coated with adhesive molecules (Cultispher S and Pronectin F) relative
to the uncoated carriers (Cytodex 1 and Immobasil FS). Experiments
where the DMEM medium was gradually replaced by the serum-free medium
(CHO-SFM-II) revealed important advantages over media containing serum,
not only for assay purposes, but also for purification of the
disintegrin. Altogether these results demonstrate that cultures on
microcarriers, especially on Pronectin F, show good potential for
larger scale cultures of rCHO-K1 cell
A next-generation liquid xenon observatory for dark matter and neutrino physics
The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector
Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): study protocol for a randomized controlled trial
BACKGROUND:
Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART).
METHODS/DESIGN:
ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH2O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure 6430 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle.
DISCUSSION:
If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration metho
The defensive strike of five species of lanceheads of the genus Bothrops (Viperidae)
We studied the defensive strike of one species of each of five recognized lineages within the genus Bothrops, namely, B. alternatus, B. jararaca, B. jararacussu, B. moojeni and B. pauloensis. The defensive strike of the studied species was in general similar to that of Crotalus viridis and C. atrox, but some important differences were observed. Bothrops alternatus and B. pauloensis struck preferentially from a tight body posture, whereas B. jararaca and B. moojeni from a loose body posture. Defensive strikes were either true or false (during the latter, the mouth remains closed or partially open). Almost all strikes were successful; only on a few occasions snakes missed their target (flawed strikes). Strike variables were very conservative among the five species, especially strike distance and height, and one possible explanation may be related to constraints imposed on strike variables as a way of increasing strike accuracy
Storage in cerrado soil and germination of Psychotria vellosiana (Rubiaceae) seeds
The regeneration of plant communities from seed depends, to a large extent, on the capacity of the seed remaining viable in the soil. The viability and germination of artificially buried Psychotria vellosiana seeds in cerrado soil were studied, with the purpose of discovering some physio-ecological aspects of dispersed seeds and evaluating their potential to constitute a soil seed bank. Seed samples were placed in nylon envelopes and buried in the soil of a Cerrado reserve at two different depths and sites. Buried seeds were retrieved periodically and tested for germination along with dry-stored seeds. In general, there was a reduction in seed germination with storage time, both in soil and dry stored conditions, and in some assays exhumed seeds germinated faster than dry stored ones. In general the soil storage favoured seed viability of ungerminated seeds as compared to dry stored ones, with the seeds remaining partially viable after 10 months of storage. The lack of germination of viable seeds suggests that seeds showed true dormancy and/or required an extended time to germinate. It was observed that some seeds had germinated while buried and such in situ germination tended to increase with rainfall. The water availability in the soil might be a limiting factor for successful germination of P. vellosiana in the field, and the seeds may constitute a persistent soil seed bank in the cerrado as dispersed seeds remain viable in the soil until the following period of seed dispersal
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