A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site

This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be ≥3--5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poisson’s ratio, P- and S-wave velocities, Young’s modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.Additional co-authors: Nick Teanby and Sharon Keda

Reasoning about Security in Mobile Ambients

The paper gives an assessment of security for Mobile Ambients, with specific focus on mandatory access control (MAC) policies in multilevel security systems. The first part of the paper reports on different formalization attempts for MAC policies in the Ambient Calculus, and provides an in-depth analysis of the problems one encounters. As it turns out, MAC security does not appear to have fully convincing interpretations in the calculus. The second part proposes a solution to this impasse, based on a variant of Mobile Ambients. A type system for resource access control is defined, and the new calculus is discussed and illustrated with several examples of resource management policies

Herança da resistência à ferrugem da folha da aveia (Puccinia coronata f. sp. avenae Fraser & Led.) em genótipos brasileiros de aveia branca Inheritance of oat leaf rust (Puccinia coronata f. sp. avenae Fraser & Led.) resistance in white oat brazilian genotypes

A ferrugem da folha da aveia é a moléstia mais importante que ataca a cultura da aveia, ocorrendo em praticamente todas as áreas em que a aveia é cultivada. A forma mais indicada para o seu controle é a utilização de cultivares resistentes. Contudo, para que seja alcançada a resistência durável ao patógeno, é necessário que se conheça a genética da resistência à ferrugem da folha em aveia. O objetivo foi determinar a forma de herança da resistência a três isolados de Puccinia coronata f. sp. avenae Fraser & Led., (coletados no sul do Brasil) em genótipos brasileiros de aveia branca. Para a determinação da herança da resistência a cada um dos três isolados, foram utilizadas populações F2 geradas por meio de cruzamentos artificiais, entre genótipos resistentes (R) e suscetíveis (S) e entre genótipos resistentes (R). Desta forma, foram utilizadas populações F2 dos cruzamentos artificiais entre: i) URPEL 15 (R) x UFRGS 7 (S), UPF 16 (R) x UFRGS 7 (S) e URPEL 15 (R) x UPF 16 (R), para a determinação da herança da resistência ao isolado um (1); ii) URPEL 15 (R) x UFRGS 7 (S), UPF 18 (R) x UFRGS 7 (S) e URPEL 15 (R) x UPF 18 (R), para a determinação da herança da resistência ao isolado dois (2); iii) URPEL 15 (R) x UFRGS 7 (S) e URPEL 15 (R) x UPF 18 (S), para a determinação da herança da resistência ao isolado três (3). Os resultados obtidos evidenciaram que o genótipo URPEL 15 apresenta genes dominantes de resistência aos três isolados de ferrugem da folha da aveia avaliados, que o cultivar UPF 16 apresenta um gene recessivo de resistência ao isolado 1 e o cultivar UPF 18 apresenta um gene recessivo de resistência ao isolado 2. E que os genes de resistência apresentados pelos genótipos URPEL 15, UPF 16 e UPF 18, segregam de forma independente.<br>Oat crown rust is the most important disease for the oat crop, occurring in practically all the areas where oat is cultivated. The most indicated form of control for this disease is the use of resistant cultivars. However, for the durable resistance to be acquired, it is necessary to know the genetics of resistance to crown rust in oats. Thus, the objective of this work was to determine the type of inheritance of resistance to three Puccinia coronata f. sp. avenae Fraser & Led., isolates (collected in southern Brazil) in brazilian white oat genotypes. To determine the inheritance of resistance to each one of three isolates,F2 populations were used generated through artificial crosses, between resistant (R) and susceptible (S) and between resistant genotypes (R). Thus, F2 populations from the following artificial crosses: i) URPEL 15 (R) x UFRGS 7 (S), UPF 16 (R) x UFRGS 7 (S) and URPEL 15 (R) x UPF 16 (R), were used to determine the inheritance of resistance to isolate one (1); ii) URPEL 15 (R) x UFRGS 7 (S), UPF 18 (R) x UFRGS 7 (S) and URPEL 15 (R) x UPF 18 (R), to determine the inheritance of resistance to isolate two (2); iii) URPEL 15 (R) x UFRGS 7 (S) and URPEL 15 (R) x UPF 18 (S), to determine the inheritance of resistance to isolate three (3). The obtained results indicate that the genotype URPEL 15 present dominants genes for resistance to the three oat leaf rust isolates evaluated, the cultivar UPF 16 presents a recessive gene for resistance to isolate 1 and the cultivar UPF 18 has a recessive gene of resistence to isolate 2. Also, the resistance genes presented by genotypes URPEL 15, UPF 16 and UPF 18, segregate in an independent manner

Ecology and Conservation of a Living Fossil: Australia’s Wollemi Pine (Wollemia nobilis)

The iconic Wollemi Pine (Wollemia nobilis) is a critically endangered Australian conifer and one of the world’s rarest trees with only 46 mature individuals remaining in the wild. The species is regarded as a “living fossil” and was discovered on the brink of extinction following a natural historical decline. While its discovery has enabled crucial intervention for its long-term conservation, it has also created novel threats. Wollemia nobilis is facing extinction in the wild due to its highly restricted distribution, extremely small population size, and ongoing impacts from exotic pathogens, inappropriate fire regimes, unauthorized site visitation, and anthropogenic climate change. A highly successful, collaborative program combining in situ management, ecological research and monitoring with public education and ex situ conservation strategies, such as translocation and commercial cultivation, is enhancing the species’ long-term survival. The extended longevity and slow growth and maturation of wild Wollemi Pine present unique challenges to effective in situ conservation, including the multidecadal timescales required to deliver certain conservation objectives. The continued success of the conservation program depends on strong forward planning, intergenerational commitment and collaboration, and ongoing public support

Detecção e variabilidade de Plasmopara halstedii no Brasil e avaliação da resistência de genótipos de girassol ao míldio Detection and variability of Plasmopara halstedii in Brazil and resistance of sunflower genotypes to downy mildew

Este trabalho foi conduzido com o objetivo de identificar a raça fisiológica de Plasmopara halstedii que ocorreu em plantas de girassol coletadas no campo experimental da Embrapa Soja, Londrina, PR, em 1998, 2001 e 2002 e avaliar a reação de genótipos de girassol ao míldio. Plântulas de girassol das diferenciadoras de raças e das cultivares foram inoculadas com suspensão de zoosporângios do patógeno e foram plantadas em caixas contendo areia autoclavada. As plântulas foram mantidas em câmara climatizada, com temperatura controlada em 21ºC, por 11 dias. Em seguida, as plantas foram aspergidas intensamente com água destilada, cobertas com saco plástico e mantidas no escuro, a 18ºC. No dia seguinte, foi observada a presença de esporulação nos cotilédones. As plantas que apresentaram esporulação foram consideradas suscetíveis e as sem esporulação foram resistentes. O resultado indicou tratar-se da raça 330 (antiga raça 7 americana), nas três ocasiões. Os genótipos de girassol Embrapa 122, BRS 191 e as cultivares de girassol ornamental BRS Capri M, BRS Encanto M, BRS Oásis, BRS Paixão M, BRS Pesqueiro M, BRS Refúgio M, BRS Saudade M e BRS Saudade U e seus respectivos parentais foram suscetíveis a P. halstedii raça 330. Os genótipos AGROBEL 910, AGROBEL 920, AGROBEL 960, AGROBEL 965, C11, EXP38, M734, M742 e RUMBOSOL 91 foram resistentes à raça 330 do patógeno e podem ser indicados aos agricultores para uso em regiões de risco de ocorrência da doença.<br>This research was carried out for identifying the physiological race of Plasmopara halstedii occurring in sunflower at the experimental field of Embrapa Soybean, Londrina, PR, Brazil, in 1998, 2001 and 2002 by evaluating the reaction of sunflower genotypes inoculated with downy mildew pathogen. Sunflower seedlings of the differentials set to identify races and of the cultivars were inoculated by immersion in zoosporangia suspension and were grown in autoclaved sand boxes. Seedlings were kept in growing chambers at 21ºC for 11 days. After this period, plants were intensively misted with distilled water, covered with plastic bag, and kept in the dark at 18ºC. In the next day, sporulation in cotyledons was observed. Plants with sporulation were considered susceptible and non-sporulated plants were resistant. Results indicated the occurrence of race 330 (former American race 7) in the three years evaluated. Sunflower genotypes Embrapa 122, BRS 191 and ornamental sunflower cultivars BRS Capri M, BRS Encanto M, BRS Oásis, BRS Paixão M, BRS Pesqueiro M, BRS Refúgio M, BRS Saudade M and BRS Saudade U and respective parents were susceptible to P. halstedii race 330. The genotypes AGROBEL 910, AGROBEL 920, AGROBEL 960, AGROBEL 965, C11, EXP38, M734, M742 and RUMBOSOL 91 were resistant to that race and can be used by the growers in regions of high potential for disease occurrence