17,359 research outputs found
The relationship of resveratrol production to infection of grapevine leaves by Botrytis cinerea
The stilbene resveratrol is one of the stress metabolites produced by grapevine (7, 8). The distribution of resveratrol in spreading lesions caused by Botrytis cinerea on detached grapevine leaves has been examined. Both the highest absolute amounts and the highest concentrations of resveratrol were found in the apparently healthy zone of tissue up to 5 mm in advance of the visibly rotted area. The distribution of resveratrol corresponded with the distribution of blue fluorescence observable macroscopically under long wavelength (366 nm) UV irradiation. The relationship between the concentration of resveratrol around B. cinerea lesions on grapevine leaves and susceptibility of those leaves to infection was investigated. Susceptibility decreased with age of the leaf and varied between the varieties of grapevine studied. In both cases, there was an inverse relationship between the concentration of resveratrol around the lesion and susceptibility. The probable role of resveratrol as the precursor of antifungal stress metabolites, the viniferins, in the disease resistance of grapevine is discussed.
Die Beziehungen zwischen der Bildung von Resveratrol und dem Befall von Rebenblättern durch Botrytis cinerea
Das Stilben Resveratrol gehört zu den Stoffwechselprodukten, die von der Rebe unter Streßbedingungen gebildet werden. An isolierten Blättern von Vitis vinifera wurde die Verteilung von Resveratrol in den sich ausbreitenden Läsionen, die durch Botrytis cinerea verursacht werden, geprüft. In einer bis zu 5 mm breiten scheinbar gesunden Gewebezone, die den visuell geschädigten Blattbezirk umgibt, wurden sowohl die höchsten Absolutmengen als auch die höchsten Konzentrationen von Resveratrol gefunden. Die Verteilung von Resveratrol entsprach dem Auftreten einer Blaufluoreszenz, die bei langwelliger UV-Bestrahlung (366 nm) makroskopisch beobachtet werden kann. Die Beziehung zwischen der Resveratrolkonzentration, die im Umkreis der Botrytis-Läsionen an Rebenblättern vorliegt, und der Anfälligkeit dieser Blätter für die Pilzinfektion wurde untersucht. Die Pilzanfälligkeit nahm mit dem Alter der Blätter ab und variierte zwischen den untersuchten Rebsorten. In beiden Fällen stand die Resveratrolkonzentration im Umkreis der Läsion im umgekehrten Verhältnis zum Anfälligkeitsgrad. Die Rolle, die Resveratrol als Präcursor pilzfeindlicher Streßmetabolite, der Viniferine, bei der Krankheitsresistenz der Rebe spielen dürfte, wird diskutiert
Mission design for a ballistic slow flyby Comet Encke 1980
Preliminary mission analyses for a proposed 1980 slow flyby (7-9 km/s) of comet Encke are presented. Among the topics covered are science objectives, Encke's physical activity and ephemeris accuracy, trajectory and launch-window analysis, terminal guidance, and spacecraft concepts. The nominal mission plan calls for a near-perihelion intercept with two spacecraft launched on a single launch vehicle. Both spacecraft will arrive at the same time, one passing within 500 km from Encke's nucleus on its sunward side, the other cutting through the tail region. By applying a small propulsive correction about three weeks after the encounter, it is possible to retarget both spacecraft for a second Encke intercept in 1984. The potential science return from the ballistic slow flyby is compared with other proposed mission modes for the 1980 Encke flyby mission, including the widely advocated slow flyby using solar-electric propulsion. It is shown that the ballistic slow flyby is superior in every respect
The Serendipitous Discovery of a Group or Cluster of young Galaxies at z=2.40 in Deep Hubble Space Telescope WFPC2 Images
We report the serendipitous discovery of a group or cluster of young galaxies
at 2.40 in a 24-orbit HST/WFPC2 exposure of the field around the weak
radio galaxy 53W002. Potential cluster members were identified on ground-based
narrow-band redshifted Ly images and confirmed via spectroscopy.
In addition to the known weak radio galaxy 53W002 at z=2.390, two other
objects were found to have excess narrow-band Ly emission at
2.40. Both have been spectroscopically confirmed, and one clearly
contains a weak AGN. They are located within one arcminute of 53W002, or
Mpc (=0.5) at 2.40, which is the physical
scale of a group or small cluster of galaxies. Profile fitting of the WFPC2
images shows that the objects are very compact, with scale lengths
0\farcs 1 (kpc), and are rather faint
(luminosities < L*), implying that they may be sub-galactic sized objects. We
discuss these results in the context of galaxy and cluster evolution and the
role that weak AGN may play in the formation of young galaxies.Comment: Accepted for publication in The Astrophysical Journal (Letters). 13
pages of gzip compressed and uuencoded PS. Figures are available at
http://www.phys.unsw.edu.au/~spd/bib.htm
The influence of baryons on the mass distribution of dark matter halos
Using a set of high-resolution N-body/SPH cosmological simulations with
identical initial conditions but run with different numerical setups, we
investigate the influence of baryonic matter on the mass distribution of dark
halos when radiative cooling is NOT included. We compare the concentration
parameters of about 400 massive halos with virial mass from \Msun to
\Msun. We find that the concentration parameters for the
total mass and dark matter distributions in non radiative simulations are on
average larger by ~3% and 10% than those in a pure dark matter simulation. Our
results indicate that the total mass density profile is little affected by a
hot gas component in the simulations. After carefully excluding the effects of
resolutions and spurious two-body heating between dark matter and gas
particles, we conclude that the increase of the dark matter concentration
parameters is due to interactions between baryons and dark matter. We
demonstrate this with the aid of idealized simulations of two-body mergers. The
results of individual halos simulated with different mass resolutions show that
the gas profiles of densities, temperature and entropy are subjects of mass
resolution of SPH particles. In particular, we find that in the inner parts of
halos, as the SPH resolution increases the gas density becomes higher but both
the entropy and temperature decrease.Comment: 8 pages, 6 figures, 1 table, ApJ in press (v652n1); updated to match
with the being published versio
The experience of enchantment in human-computer interaction
Improving user experience is becoming something of a rallying call in human–computer interaction but experience is not a unitary thing. There are varieties of experiences, good and bad, and we need to characterise these varieties if we are to improve user experience. In this paper we argue that enchantment is a useful concept to facilitate closer relationships between people and technology. But enchantment is a complex concept in need of some clarification. So we explore how enchantment has been used in the discussions of technology and examine experiences of film and cell phones to see how enchantment with technology is possible. Based on these cases, we identify the sensibilities that help designers design for enchantment, including the specific sensuousness of a thing, senses of play, paradox and openness, and the potential for transformation. We use these to analyse digital jewellery in order to suggest how it can be made more enchanting. We conclude by relating enchantment to varieties of experience.</p
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Making Sense of Family Deaths in Urban Senegal: Diversities, Contexts, and Comparisons
Despite calls for cross-cultural research, Minority world perspectives still dominate death and bereavement studies, emphasizing individualized emotions and neglecting contextual diversities. In research concerned with contemporary African societies, on the other hand, death and loss are generally subsumed within concerns about AIDS or poverty, with little attention paid to the emotional and personal significance of a death. Here, we draw on interactionist sociology to present major themes from a qualitative study of family deaths in urban Senegal, theoretically framed through the duality of meanings-in-context. Such themes included family and community as support and motivation; religious beliefs and practices as frameworks for solace and (regulatory) meaning; and material circumstances as these are intrinsically bound up with emotions. Although we identify the experience of (embodied, emotional) pain as a common response across Minority and Majority worlds, we also explore significant divergencies, varying according to localized contexts and broader power dynamics
Assessing Human Error Against a Benchmark of Perfection
An increasing number of domains are providing us with detailed trace data on
human decisions in settings where we can evaluate the quality of these
decisions via an algorithm. Motivated by this development, an emerging line of
work has begun to consider whether we can characterize and predict the kinds of
decisions where people are likely to make errors.
To investigate what a general framework for human error prediction might look
like, we focus on a model system with a rich history in the behavioral
sciences: the decisions made by chess players as they select moves in a game.
We carry out our analysis at a large scale, employing datasets with several
million recorded games, and using chess tablebases to acquire a form of ground
truth for a subset of chess positions that have been completely solved by
computers but remain challenging even for the best players in the world.
We organize our analysis around three categories of features that we argue
are present in most settings where the analysis of human error is applicable:
the skill of the decision-maker, the time available to make the decision, and
the inherent difficulty of the decision. We identify rich structure in all
three of these categories of features, and find strong evidence that in our
domain, features describing the inherent difficulty of an instance are
significantly more powerful than features based on skill or time.Comment: KDD 2016; 10 page
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