19 research outputs found
Picking a CHERI Allocator: Security and Performance Considerations
Several open-source memory allocators have been ported to CHERI, a hardware
capability platform. In this paper we examine the security and performance of
these allocators when run under CheriBSD on Arm's experimental Morello
platform. We introduce a number of security attacks and show that all but one
allocator are vulnerable to some of the attacks - including the default
CheriBSD allocator. We then show that while some forms of allocator performance
are meaningful, comparing the performance of hybrid and pure capability (i.e.
'running in non-CHERI vs. running in CHERI modes') allocators does not appear
to be meaningful. Although we do not fully understand the reasons for this, it
seems to be at least as much due to factors such as immature compiler
toolchains as it is due to the effects of capabilities on hardware
Carotenoid accumulation during tomato fruit ripening is modulated by the auxin-ethylene balance
Background : Tomato fruit ripening is controlled by ethylene and is characterized by a shift in color from green to red, a strong accumulation of lycopene, and a decrease in ÎČ-xanthophylls and chlorophylls. The role of other hormones, such as auxin, has been less studied. Auxin is retarding the fruit ripening. In tomato, there is no study of the carotenoid content and related transcript after treatment with auxin. Results : We followed the effects of application of various hormone-like substances to âMature-Greenâ fruits. Application of an ethylene precursor (ACC) or of an auxin antagonist (PCIB) to tomato fruits accelerated the color shift, the accumulation of lycopene, α-, ÎČ-, and ÎŽ-carotenes and the disappearance of ÎČ-xanthophylls and chlorophyll b. By contrast, application of auxin (IAA) delayed the color shift, the lycopene accumulation and the decrease of chlorophyll a. Combined application of IAA + ACC led to an intermediate phenotype. The levels of transcripts coding for carotenoid biosynthesis enzymes, for the ripening regulator Rin, for chlorophyllase, and the levels of ethylene and abscisic acid (ABA) were monitored in the treated fruits. Correlation network analyses suggest that ABA, may also be a key regulator of several responses to auxin and ethylene treatments.
Conclusions : The results suggest that IAA retards tomato ripening by affecting a set of (i) key regulators, such as Rin, ethylene and ABA, and (ii) key effectors, such as genes for lycopene and ÎČ-xanthophyll biosynthesis and for chlorophyll degradation