4,580 research outputs found
Innovation Broker Functions in Regional Innovation Systems. A case study of Food Valley Organization
Infrared Surface Brightness Analysis of Galaxies in Compact Groups
Images of 7 Compact groups of galaxies (CG) were obtained using the 2.1m
telescope in San Pedro Martir (B.C. Mexico) equipped with the NIR camera
CAMILA. The NIR images trace the mass of the galaxies, through the oldest and
more evolved stellar populations. The goal of this project is to search for
evidence of morphological perturbations correlated with the level of activity
(AGN or star formation) of the galaxies. We find that the level of perturbation
is well correlated with activity observed in optical spectrocopy (Coziol et al.
2004). Evidence for perturbations decreases from more active groups to less
active groups, confirming the classification. Our analysis suggests that
galaxies in more active groups are undergoing important transformations due to
interaction and merging and that the whole groups is on a merger path. Galaxies
in less active CG have gone through similar processes in the recent past and
are either in a final merging phase or in equilibrium due to a more massive
halo of dark matter.Comment: 2 pages, 1 figure, Proc. ESO Workshop "Groups of galaxies in the
nearby Universe", Santiago, Chile, 5-9 Dec. 2005, ESO Astrophysics Symposia,
eds. I. Saviane, V. Ivanov & J. Borissova, Springer-Verla
An Introduction to Pervasive Interface Automata
Pervasive systems are often context-dependent, component based systems in which components expose interfaces and offer one or more services. These systems may evolve in unpredictable ways, often through component replacement. We present pervasive interface automata as a formalism for modelling components and their composition. Pervasive interface automata are based on the interface automata of Henzinger et al, with several significant differences. We expand their notion of input and output actions to combinations of input, output actions, and callable methods and method calls. Whereas interfaces automata have a refinement relation, we argue the crucial relation in pervasive systems is component replacement, which must include consideration of the services offered by a component and assumptions about the environment. We illustrate pervasive interface autmotata and component replacement with a small case study of a pervasive application for sports predictions
Mortality and top-kill in Douglas-fir following defoliation by the western spruce budworm in British Columbia
Surveys of mortality and top-kill caused by the western spruce budworm, <i>Choristoneura occidentalis</i> Freeman, in 65 stands of Douglas-fir, <i>Pseudotsuga menziesii</i> (Mirb.) Franco are reported. Top-kill was detected in 85% of the stands and 25% of the trees surveyed. Mortality amounted to 8% and less than 1% of the trees examined in the Vancouver and Kamloops Forest Regions, respectively. Both frequency of top-kill and mortality were related to the number of years defoliation in the stand and were higher on suppressed trees than on dominant or co-dominant trees. Younger stands sustained a higher incidence of topkill than older stands. Tree mortality was higher on steep slopes than on flat terrain. These results suggested that top-kill or mortality were the results of physiological stress on the trees, in addition to the debilitating effects of defoliation
Fifty-year-old Sitka spruce plantations with a history of intense weevil attack
The condition of 26 plantations of Sitka spruce (<i>Picea sitchensis</i> (Bong) Carr.) established between 1930 and 1935, at Green Timbers, Surrey, British Columbia, which sustained repeated attack by the white pine weevil (<i>Pissodes strobi</i> Peck) was examined in 1981. The plantations were started either as pure Sitka spruce or as a mixture of spruce and Douglas-fir (<i>Pseudotsuga menziesii</i> (Mirb.) Franco). A detailed survey was conducted in one plantation of each type for which annual infestation levels were recorded from 1936 to 1949 and which appeared to be typical of the rest of the pure and mixed plantations.Many Sitka spruce trees were dead. having been out-competed by the other trees on the site as a result of repeated top-killing by <i>P. strobi</i>. Most surviving spruce trees were badly deformed, showed signs of severe attack, and were nonmerchantable. The plantation of pure Sitka spruce contained about 176 living Sitka spruce trees/ha, but only about 14 trees/ha were potential crop trees: the rest were suppressed or deformed. This plantation contained more volume in other volunteer conifers than in Sitka spruce. The mixed plantation developed into a merchantable stand of almost pure Douglas-fir, with only 5-6 Sitka spruce trees/ha
Root-associated fungal communities colonizing two dominant semiarid grasses: Hilaria sp. and Stipa sp.
We conducted a preliminary survey of the fungal communities associated with roots of Stipa hymenoides and Hilaria jamesii, two grasses native to the southwestern United States. Root samples from 10 different plants were collected at a semiarid grassland in Utah. Fungal communities were assessed using microscopic and molecular methods. Roots were cleared with KOH and stained using blue ink to visualize mycorrhizal and endophytic fungi. A total of 100 root segments were surface sterilized and plated on malt extract agar with antibiotics. Fungal endophytes were identified using nrITS primers.

Results/Conclusions

Microscopic analyses showed that all root samples from both Hillaria and Stipa were colonized by dark septate and arbuscular mycorrhizal fungi. Vesicles and hyaline hyphae also were observed in all the roots. Sclerotia, a characteristic structure of some dark septate fungi were also found. Approximately 75 fungi were isolated representing at least 45 morphotypes. Molecular identification showed that both grasses are colonized by endophytes in the orders Pleosporales, Hypocreales, and Sordariales commonly found in semiarid grasses, liverworts, and mosses
Biopesticide activity from drimanic compounds to control tomato pathogens
Indexación: Scopus.Tomato crops can be affected by several infectious diseases produced by bacteria, fungi, and oomycetes. Four phytopathogens are of special concern because of the major economic losses they generate worldwide in tomato production; Clavibacter michiganensis subsp. michiganensis and Pseudomonas syringae pv. tomato, causative agents behind two highly destructive diseases, bacterial canker and bacterial speck, respectively; fungus Fusarium oxysporum f. sp. lycopersici that causes Fusarium Wilt, which strongly affects tomato crops; and finally, Phytophthora spp., which affect both potato and tomato crops. Polygodial (1), drimenol (2), isonordrimenone (3), and nordrimenone (4) were studied against these four phytopathogenic microorganisms. Among them, compound 1, obtained from Drimys winteri Forst, and synthetic compound 4 are shown here to have potent activity. Most promisingly, the results showed that compounds 1 and 4 affect Clavibacter michiganensis growth at minimal inhibitory concentrations (MIC) values of 16 and 32 μg/mL, respectively, and high antimycotic activity against Fusarium oxysporum and Phytophthora spp. with MIC of 64 μg/mL. The results of the present study suggest novel treatment alternatives with drimane compounds against bacterial and fungal plant pathogens. © 2018 by the authors.https://www.mdpi.com/1420-3049/23/8/205
The eccentric short-period orbit of the supergiant fast X-ray transient HD 74194 (=LM Vel)
Aims. We present the first orbital solution for the O-type supergiant star HD
74194, which is the optical counterpart of the supergiant fast X-ray transient
IGR J08408-4503. Methods. We measured the radial velocities in the optical
spectrum of HD 74194, and we determined the orbital solution for the first
time. We also analysed the complex H{\alpha} profile. Results. HD 74194 is a
binary system composed of an O-type supergiant and a compact object in a
short-period ( d) and high-eccentricity ()
orbit. The equivalent width of the H{\alpha} line is not modulated entirely
with the orbital period, but seems to vary in a superorbital period
( d) nearly 30 times longer than the orbital one.Comment: 4 pages, 6 figures, accepted for publication in A&
New insight into WDVV equation
We show that Witten-Dijkgraaf-Verlinde-Verlinde equation underlies the
construction of N=4 superconformal multi--particle mechanics in one dimension,
including a N=4 superconformal Calogero model.Comment: 16 pages, no figures, LaTeX file, PACS: 04.60.Ds; 11.30.P
The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars
We present the second installment of GOSSS, a massive spectroscopic survey of
Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R ~
2500 digital observations from both hemispheres selected from the Galactic
O-Star Catalog (GOSC). In this paper we include bright stars and other objects
drawn mostly from the first version of GOSC, all of them south of delta = -20
degrees, for a total number of 258 O stars. We also revise the northern sample
of paper I to provide the full list of spectroscopically classified Galactic O
stars complete to B = 8, bringing the total number of published GOSSS stars to
448. Extensive sequences of exceptional objects are given, including the early
Of/WN, O Iafpe, Ofc, ON/OC, Onfp, Of?p, and Oe types, as well as
double/triple-lined spectroscopic binaries. The new spectral subtype O9.2 is
also discussed. The magnitude and spatial distributions of the observed sample
are analyzed. We also present new results from OWN, a multi-epoch
high-resolution spectroscopic survey coordinated with GOSSS that is assembling
the largest sample of Galactic spectroscopic massive binaries ever attained.
The OWN data combined with additional information on spectroscopic and visual
binaries from the literature indicate that only a very small fraction (if any)
of the stars with masses above 15-20 M_Sol are born as single systems. In the
future we will publish the rest of the GOSSS survey, which is expected to
include over 1000 Galactic O stars.Comment: 110 pages, 16 figures, accepted for publication in ApJS. Some figures
have low quality due to arXiv file size limitations, alternative version
available at http://jmaiz.iaa.es/files/Sotaetal14.pd
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