Catching Spiral - S0 transition in groups. Insights from SPH simulations with chemo-photometric implementation

We are investigating the co-evolution of galaxies within groups combining multi-wavelength photometric and 2D kinematical observations. Here we focus on S0s showing star formation in ring/arm-like structures. We use smooth particle hydrodynamical simulations (SPH) with chemo-photometric implementation which provide dynamical and morphological information together with the spectral energy distribution (SED) at each evolutionary stage. As test cases, we simulate the evolution of two such S0s: NGC 1533 and NGC 3626. The merging of two halos with mass ratio 2:1, initially just composed of dark matter (DM) and gas, well match their observed SEDs, their surface brightness profiles and their overall kinematics. The residual star formation today "rejuvenating" the ring/arm like structures in these S0s is then a mere consequence of a major merger, i.e. this is a phase during the merger episode. The peculiar kinematical features, e.g. gas-stars counter rotation in NGC 3626, depends on the halos initial impact parameters. Furthermore, our simulations allow to follow, in a fully consistent way, the transition of these S0s through the green valley in the NUV-r vs. Mr colour magnitude diagram, which they cross in about 3-5 Gyr, before reaching their current position in the red sequence. We conclude that a viable mechanism driving the evolution of S0s in groups is of gravitational origin.Comment: 30 pages, 6 figures; accepted for publication in Advances in Space Research, Special Issue: Ultraviolet Astrophysic

On Semiclassical Limits of String States

We explore the relation between classical and quantum states in both open and closed (super)strings discussing the relevance of coherent states as a semiclassical approximation. For the closed string sector a gauge-fixing of the residual world-sheet rigid translation symmetry of the light-cone gauge is needed for the construction to be possible. The circular target-space loop example is worked out explicitly.Comment: 12 page

Wearable wireless tactile display for virtual interactions with soft bodies.

We describe here a wearable, wireless, compact, and lightweight tactile display, able to mechanically stimulate the fingertip of users, so as to simulate contact with soft bodies in virtual environments. The device was based on dielectric elastomer actuators, as high-performance electromechanically active polymers. The actuator was arranged at the user's fingertip, integrated within a plastic case, which also hosted a compact high-voltage circuitry. A custom-made wireless control unit was arranged on the forearm and connected to the display via low-voltage leads. We present the structure of the device and a characterization of it, in terms of electromechanical response and stress relaxation. Furthermore, we present results of a psychophysical test aimed at assessing the ability of the system to generate different levels of force that can be perceived by users.The authors gratefully acknowledge financial support from COST – European Cooperation in Science and Technology, within the framework of “ESNAM – European Scientific Network for Artificial Muscles” (COST Action MP1003). Gabriele Frediani also acknowledges support from the European Commission, within the framework of the project “CEEDS: The Collective Experience of Empathic Data Systems” (FP7-ICT-2009.8.4, Grant 258749) and “Fondazione Cassa di Risparmio di Pisa,” within the framework of the project “POLOPTEL” (Grant 167/09

Photometric evolution of dusty starburst mergers:On the nature of ultra-luminous infrared galaxies

By performing N-body simulations of chemodynamical evolution of galaxies with dusty starbursts, we investigate photometric evolution of gas-rich major mergers in order to explore the nature of ultraluminous infrared galaxies (ULIRGs) with the total infrared luminosity ($L_{\rm IR}$ for $8\sim 1000$ $\mu$m) of $\sim$ $10^{12}$ $L_{\odot}$. Main results are the following three. (1) Global colors and absolute magnitudes the during dusty starburst of a major merger do not change with time significantly, because interstellar dust heavily obscures young starburst populations that could cause rapid evolution of photometric properties of the merger. (2) Dust extinction of stellar populations in a galaxy merger with large infrared luminosity ($L_{\rm IR}$ $>$ $10^{11}$ $L_{\odot}$) is selective in the sense that younger stellar populations are preferentially obscured by dust than old ones. This is because younger populations are located in the central region where a larger amount of dusty interstellar gas can be transferred from the outer gas-rich regions of the merger. (3) Both $L_{\rm IR}$ and the ratio of $L_{\rm IR}$ to $B$ band luminosity $(L_{\rm B}$) increases as the star formation rate increase during the starburst of the present merger model, resulting in the positive correlation between $L_{\rm IR}$ and $L_{\rm IR}/L_{\rm B}$.Comment: 32 pages 25 figures,2001,ApJ,in press. For all 25 PS figures (including fig25.ps), see http://newt.phys.unsw.edu.au/~bekki/res.dir/paper.dir/apj06.dir/fig.tar.g

Galaxy evolution in nearby groups. II. Galaxy evolution in nearby loose groups. II. Photometric and kinematic characterization of USGC U268 and USGC U376 group members in the Leo cloud

We present the photometric and kinematic characterization of two groups, USGC U268 and USGC U376 located in different regions of the Leo cloud. U268, composed of 10 catalogued members and 11 new added members, has a small fraction (~24%) of early-type galaxies (ETGs). U376 has 16 plus 8 new added members, with ~38% of ETGs. We find the presence of significant substructures in both groups suggesting that they are likely accreting galaxies. U268 is located in a more loose environment than U376. For each member galaxy, broad band integrated and surface photometry have been obtained in far-UV and near-UV with GALEX, and in u,g, r, i, z (SDSS) bands. H_alpha imaging and 2D high resolution kinematical data have been obtained using PUMA Scanning Fabry-Perot interferometer at the 2.12 m telescope in San Pedro M\'artir, (Baja California, M\'exico). We improved the galaxy classification and we detected morphological and kinematical distortions that may be connected to either on-going and/or past interaction/accretion events or environmental induced secular evolution. U268 appears more active than U376, with a large fraction of galaxies showing interaction signatures (60% vs. 13%). The presence of bars among late-type galaxies is ~10% in U268 and ~$29% in U376. The cumulative distribution of (FUV - NUV) colours of galaxies in U268 is significantly different than that in U376 with galaxies in U268 bluer than those in U376. In the (FUV-r vs. M_r) and (NUV-r vs. M_r) planes no members of U268 are found in the `red sequence', even early-type galaxies lie in the `blue sequence' or in the `green valley'. Most (80%) of the early-type members in U376 inhabits the `red sequence, a large fraction of galaxies, of different morphological types, are located in the `green valley', while the `blue sequence' is under-populated with respect to U268.Comment: 27 pages, 11 figures, 8 tables, accepted for publication in MNRAS (abridged abstract

Investigation of the Effect of Ultrasound Parameters on Continuous Sonocrystallization in a Millifluidic Device

© 2016 American Chemical Society. Continuous-flow crystallization of adipic acid in a millichannel chip equipped with a piezoelectric element is presented and investigated experimentally and numerically. A single, straight channel chip (cross section: 2 mm × 5 mm, length: 76 mm) made of glass, which is ultrasonically transparent, was designed and fabricated. The piezoelectric element allows studying the effect of different ultrasound frequencies in the kHz to MHz range. Ultrasound was applied in burst mode to reduce heating; this allowed operating at higher levels of input power. To accurately control the temperature of the fluid, Peltier elements were used to cool the bottom and top surfaces of the chip. Crystallization was performed in isothermal conditions, ensuring that the temperature and in turn the supersaturation were kept uniform along the channel. The effect of ultrasound frequency and sonication time was studied. Crystal size distributions at different operating conditions were obtained by laser diffraction. The distributions were narrow, with coefficients of variation â0.5, while the mean sizes were small (â30 μm) and decreased when the sonication time increased. The crystal production rate increased by increasing the sonication time; this suggests that ultrasound enhances nucleation. On the other hand, in crystal breakage experiments, no difference in the size distribution of the seed crystals entering and leaving the device was observed, and hence, in this setup, ultrasound does not cause breakage. Numerical simulations of wave propagation in aqueous solution were utilized to predict the probability of cavitation, adopting a suitable cavitation threshold. The simulations showed that high pressure amplitudes are achievable inside the channel at low frequencies. The size range of bubbles which undergo violent collapse at different pressure amplitudes and frequencies was quantified. By increasing the frequency in the simulations, it was observed that the probability of transient cavitation decreases. The theoretical prediction of negligible transient cavitation at higher frequencies, in conjunction with the absence of crystals at such frequencies, indicates a strong link between transient cavitation and sonocrystallization

Avaliação do crescimento de espécies florestais por grupo ecológico em áreas exploradas na Flona do Tapajós.

III ENAAg

Milk quality, manufacturing properties and blood biochemical profile from dairy cows fed peas ( Pisum sativum L.) as dietary protein supplement

Abstract. Pea (Pisum sativum L.), a protein-rich legume seed well adapted to many climatic areas and widely used for feed and food, was fed to Italian Friesian breed cows for 16 weeks to assess its effects on milk yield and production, renneting properties and metabolic responses. Cows within each group were assigned to two isonitrogenous and isoenergetic concentrates based on corn plus soybean meal or peas. Individual milk samples were collected from two consecutive milkings, composited, and then analysed for fat, protein, casein and lactose contents and somatic cells count as well as blood and milk urea and milk technological characteristics. Cow blood samples were taken and plasma were analysed for metabolites, biological enzymes, β-hydroxybutyrate (BHBA) and non-esterified fatty acids (NEFA). Peas supplementation had no effects on metabolic blood profile as well as on milk composition traits and clotting aptitude. Milk and blood from cows fed peas indicated a reduction (P<0.05) of their urea concentrations compared to those fed soybean meal. Our findings indicate that peas can replace soybean meal as protein source in diet of dairy cows without unfavourable effects on milk quality and cheesemaking properties