Peri-urban agriculture in Barcelona. Outlining landscape dynamics vis \ue0 vis socio-environmental functions

Dispersed urbanisation promotes complex relationships between rural areas and the urban fringe, with emerging new functions for peri-urban agriculture (PUA). Although PUA is a type of productive farming of interest for urban planning due to its recognised functions, comparative analyses are needed to relate farm dynamics to fringe landscape modifications in different socio-economic contexts. Given the current limitation of specific methodologies to analyse PUA dynamics, a quantitative approach profiling farm types and the related landscape structure in an expanding urban region, the Metropolitan Area of Barcelona, is proposed. Results indicate that PUA is based on five typologies with different territorial values, as a consequence of diverse economic relevance, socio-environmental weight and landscape prominence. Based on these results, a conservation strategy aimed at preserving the residual PUA landscape is proposed through the promotion of a polycentric functional network of farming with natural vegetation

Potensi ekstrak daun Tagetes erecta (Asteracea) sebagai racun kontak terhadap Nezara viridula (Hemiptera: Pentatomidae)

Nezara viridula merupakan salah satu hama penting pada tanaman kedelai. Kerugian yang ditimbulkan adalah menurunnya hasil secara kuantitas dan kualitas biji kedelai.Tujuan dari penelitian ini untuk mengetahui potensi ekstrak daun Tagetes erecta sebagai racun kontak terhadap N. viridula. Penelitian ini menggunakan Rancangan Acak Lengkap dengan perlakuan pemberian ekstrak daun T. erecta pada enam taraf konsentrasi yaitu 0.0125%, 0.03125%, 0.0625%, 0.125%, 0.25%, 0.5% dan kontrol. Pengujian dilakukan dengan metode racun kontak. Variabel yang diamati adalah mortalitas, jumlah telur yang diletakkan dan jumlah nimfa yang terbentuk. Hasil penelitian menunjukkan bahwa konsentrasi ekstrak kasar daun T. erecta mempengaruhi mortalitas, jumlah telur dan jumlah nimfa. Mortalitas N. viridula mencapai 93.33% dan 80% masing-masing pada konsentrasi 0.5% dan 0.25%, sedangkan pada konsentrasi uji yang lebih rendah mortalitas berkisar 60-70%. Jumlah telur adalah rata-rata 161.33 dan 137 butir sementara itu keberhasilan telur menetas menjadi nimfa adalah rata-rata 161.33 dan 137 butir. Umumnya telur-telur yang diletakkan sebelum serangga mati berhasil menjadi nimfa. Ekstrak daun Tagetes erecta mempunyai potensi untuk mengendalikan N. viridula yang diaplikasikan secara konta

Modeling the Enceladus plume--plasma interaction

We investigate the chemical interaction between Saturn's corotating plasma and Enceladus' volcanic plumes. We evolve plasma as it passes through a prescribed H2O plume using a physical chemistry model adapted for water-group reactions. The flow field is assumed to be that of a plasma around an electrically-conducting obstacle centered on Enceladus and aligned with Saturn's magnetic field, consistent with Cassini magnetometer data. We explore the effects on the physical chemistry due to: (1) a small population of hot electrons; (2) a plasma flow decelerated in response to the pickup of fresh ions; (3) the source rate of neutral H2O. The model confirms that charge exchange dominates the local chemistry and that H3O+ dominates the water-group composition downstream of the Enceladus plumes. We also find that the amount of fresh pickup ions depends heavily on both the neutral source strength and on the presence of a persistent population of hot electrons.Comment: 10 pages, 1 table, 2 figure

HST/STIS Observations of Ganymede's Auroral Ovals at Eastern Elongation

We report on new Space Telescope Imaging Spectrograph (STIS) observations of Ganymede s auroral emissions obtained (to be obtained) during two visits with the Hubble Space Telescope (HST). The observations of the first visit, a five orbits, were obtained on November 19, 2010 and the second visit, also a five orbits, is scheduled for opposition in October/November 2011. We will present results of the full campaign, in case of a successful execution of the second visit. Our observations cover more than half a cycle of system III longitudes of Ganymede s positions within Jupiter s magnetosphere for each visit. We analyze the observations with respect to brightness and locations of Ganymede auroral ovals. Our goal is to set constrains on the interaction of Ganymede s mini-magnetosphere with Jupiter s magnetosphere, Ganymede s magnetic field and plasma environment, and if possible on Ganymede s neutral atmosphere

The roles of charge exchange and dissociation in spreading Saturn's neutral clouds

Neutrals sourced directly from Enceladus's plumes are initially confined to a dense neutral torus in Enceladus's orbit around Saturn. This neutral torus is redistributed by charge exchange, impact/photodissociation, and neutral-neutral collisions to produce Saturn's neutral clouds. Here we consider the former processes in greater detail than in previous studies. In the case of dissociation, models have assumed that OH is produced with a single speed of 1 km/s, whereas laboratory measurements suggest a range of speeds between 1 and 1.6 km/s. We show that the high-speed case increases dissociation's range of influence from 9 to 15 Rs. For charge exchange, we present a new modeling approach, where the ions are followed within a neutral background, whereas neutral cloud models are conventionally constructed from the neutrals' point of view. This approach allows us to comment on the significance of the ions' gyrophase at the moment charge exchange occurs. Accounting for gyrophase: (1) has no consequence on the H2O cloud; (2) doubles the local density of OH at the orbit of Enceladus; and (3) decreases the oxygen densities at Enceladus's orbit by less than 10%. Finally, we consider velocity-dependent, as well as species-dependent cross sections and find that the oxygen cloud produced from charge exchange is spread out more than H2O, whereas the OH cloud is the most confined.Comment: Accepted to the Journal of Geophysical Research, 49 pages, 10 figure

Models of Star-Planet Magnetic Interaction

Magnetic interactions between a planet and its environment are known to lead to phenomena such as aurorae and shocks in the solar system. The large number of close-in exoplanets that were discovered triggered a renewed interest in magnetic interactions in star-planet systems. Multiple other magnetic effects were then unveiled, such as planet inflation or heating, planet migration, planetary material escape, and even modification of the host star properties. We review here the recent efforts in modelling and understanding magnetic interactions between stars and planets in the context of compact systems. We first provide simple estimates of the effects of magnetic interactions and then detail analytical and numerical models for different representative scenarii. We finally lay out a series of future developments that are needed today to better understand and constrain these fascinating interactions.Comment: 23 pages, 10 figures, accepted as a chapter in the Handbook of Exoplanet

Ganymede MHD Model: Magnetospheric Context for Juno's PJ34 Flyby

On June 7th, 2021 the Juno spacecraft visited Ganymede and provided the first in situ observations since Galileo's last flyby in 2000. The measurements obtained along a one-dimensional trajectory can be brought into global context with the help of three-dimensional magnetospheric models. Here we apply the magnetohydrodynamic model of Duling et al. (2014) to conditions during the Juno flyby. In addition to the global distribution of plasma variables we provide mapping of Juno's position along magnetic field lines, Juno's distance from closed field lines and detailed information about the magnetic field's topology. We find that Juno did not enter the closed field line region and that the boundary between open and closed field lines on the surface matches the poleward edges of the observed auroral ovals. To estimate the sensitivity of the model results, we carry out a parameter study with different upstream plasma conditions and other model parameters

Phonon and Elastic Instabilities in MoC and MoN

We present several results related to the instability of MoC and MoN in the B1 (sodium chloride) structure. These compounds were proposed as potential superconductors with moderately high transition temperatures. We show that the elastic instability in B1-structure MoN, demonstrated several years ago, persists at elevated pressures, thus offering little hope of stabilizing this material without chemical doping. For MoC, another material for which stoichiometric fabrication in the B1-structure has not proven possible, we find that all of the cubic elastic constants are positive, indicating elastic stability. Instead, we find X-point phonon instabilities in MoC (and in MoN as well), further illustrating the rich behavior of carbo-nitride materials. We also present additional electronic structure results for several transition metal (Zr, Nb and Mo) carbo-nitride systems and discuss systematic trends in the properties of these materials. Deviations from strict electron counting dependencies are apparent.Comment: 5 pages and 4 trailing figures. Submitted to PR