State University of Santa Cruz

About: State University of Santa Cruz is a education organization based out in Ilhéus, Brazil. It is known for research contribution in the topics: Population & Species richness. The organization has 3266 authors who have published 4642 publications receiving 51876 citations. The organization is also known as: Universidade Estadual de Santa Cruz.

Synthesis and characterization of novel ZrO2-SiO2 mixed oxides

Abstract: In this study the mixed oxides ZrO2-SiO2, were synthesized by the sol-gel method with a molar ratio of 95:5 (Si/metal) and characterized by X-ray diffraction, absorption-desorption of N2, Fourier transform infrared spectroscopy, thermal gravimetric analysis, temperature-programmed desorption of ammonia, and acidity test by titration. The synthesized materials, which are amorphous to X-rays, are composed of a mixture of micro- and mesopores. They show a higher acid strength than the separate oxides, indicating that the ZrO2 is highly dispersed in the silica matrix.

Optical substructure and BCG offsets of Sunyaev-Zel'dovich and X-ray-selected galaxy clusters

Abstract: We used optical imaging and spectroscopic data to derive substructure estimates for local Universe ($z < 0.11$) galaxy clusters from two different samples. The first was selected through the Sunyaev-Zel'dovich (SZ) effect by the Planck satellite and the second is an X-ray selected sample. In agreement to X-ray substructure estimates we found that the SZ systems have a larger fraction of substructure than the X-ray clusters. We have also found evidence that the higher mass regime of the SZ clusters, compared to the X-ray sample, explains the larger fraction of disturbed objects in the Planck data. Although we detect a redshift evolution in the substructure fraction, it is not sufficient to explain the different results between the higher-z SZ sample and the X-ray one. We have also verified a good agreement ($\sim$60$\%$) between the optical and X-ray substructure estimates. However, the best level of agreement is given by the substructure classification given by measures based on the brightest cluster galaxy (BCG), either the BCG$-$X-ray centroid offset, or the magnitude gap between the first and second BCGs. We advocate the use of those two parameters as the most reliable and cheap way to assess cluster dynamical state. We recommend an offset cut of $\sim$0.01$\times$R$_{500}$ to separate relaxed and disturbed clusters. Regarding the magnitude gap the separation can be done at $\Delta m_{12} = 1.0$. The central galaxy paradigm (CGP) may not be valid for $\sim$20$\%$ of relaxed massive clusters. This fraction increases to $\sim$60$\%$ for disturbed systems.

Two-dimensional warm gas kinematics in interacting galaxy systems

Abstract: Gas reservoirs, internal or acquired, play an important role in the secular evolution of interacting galaxies, since they are able to enhance/trigger star formation episodes and, probably, feed the activity of active galactic nuclei. Using Fabry‐Perot observations, we have mapped, in the Hα line, the warm (T ≈ 10 4 )g as distribution and the velocity fields of the galaxy members of five interacting, gas-rich galaxy systems. We investigated two M51-like systems (Arp 70 and Arp 74), two systems containing highly disrupted members (WBL 366 and RR 24) and a case of merging in progress (Arp 299, one of the nearest luminous infrared objects). We detected gas motions following the elongated arm/tail of Arp 70b, while in the fainter member of the pair of galaxies, Arp 70a, the gas distribution is off-centred with respect to the stellar isophotes, suggesting an external acquisition. Our kinematic data highlighted noncircular motions in the velocity field of one of the members of Arp 74 (Arp 74a). The two galaxies of the RR 24 system are connected by one tidal tail, through which the kinematically disturbed component RR 24b seems to supply warm gas to RR 24a. In spite of the nearly irregular gas distribution and perturbed morphology, WBL 366a (the star-forming galaxy VV523) and WBL 366b have nearly regular velocity fields. The velocity field in the Arp 299 system is irregular, and gas flow between the two nuclei is detected. The present observations, discussed in the light of model predictions and complementary observations from the literature, suggest that all these systems are still probably in an early phase of the encounter. However, the ionized gas distribution and kinematics are strongly influenced by tidal forces. In particular, cross-fuelling mechanisms between galaxies are in action. In Arp 299 the warm and cold gaseous components show similar kinematic properties, although the cold gas seems to maintain a still better organized motion with respect to the warm gas. Ke yw ords: galaxies: general ‐ galaxies: interactions ‐ galaxies: kinematics and dynamics.

Leaf gas exchange, chlorophyll fluorescence and pigment indexes of Eugenia uniflora L. in response to changes in light intensity and soil flooding.

Abstract: Summary The interactive effects of changing light intensity and soil flooding on the photosynthetic performance of Eugenia uniflora L. (Myrtaceae) seedlings in containers were examined. Two hypotheses were tested: (i) the photosynthetic apparatus of shade-adapted leaves can be rapidly acclimated to high light after transfer from shade to full sun, and (ii) photosynthetic acclimation to changing light intensity may be influenced by soil flooding. Seedlings cultivated in a shade house (40% of full sun, ≈ 12 mol m −2 day −1 ) for 6 months were transferred to full sun (20–40 mol m −2 day −1 ) or shade (30% of full sun, ≈ 8 mol m −2 day −1 ) and subjected to soil flooding for 23 days or not flooded. Chlorophyll content index (CCI), chlorophyll fluorescence, leaf weight per area (LWA), photosynthetic light–response curves and leaf reflectance indexes were measured during soil flooding and after plants were unflooded. The CCI values increased throughout the experiment in leaves of shaded plants and decreased in leaves of plants transferred to full sun. There were no significant interactions between light intensity and flooding treatments for most of the variables analyzed, with the exception of Fv/Fm 22 days after plants were flooded and 5 days after flooded plants were unflooded. The light environment significantly affected LWA, and light environment and soil flooding significantly affected the light-saturated gross CO2 assimilation rate expressed on area and dry weight bases (Amax-area and Amax-wt, respectively), stomatal conductance of water vapor (gssat) and intrinsic water use efficiency (A/gs). Five days after flooded plants were unflooded, the normalized difference vegetation index (NDVI) and the scaled photochemical reflectance index (sPRI) were significantly higher in shade than in sun leaves. Thirty days after transferring plants from the shade house to the light treatment, LWA was 30% higher in sun than in shade leaves, and Amax-area and gssat were 59% and 99% higher, respectively, in shade than in sun leaves. Changes in CCI, NDVI and sPRI in leaves of E. uniflora seedlings transferred from shade to full sun appear to be associated with changes in pigment composition and protective mechanisms against excess light.