Non-Avian Reptiles of the state of Rio de Janeiro, Brazil: status of knowledge and commented list

We assessed the current knowledge on non-avian reptile species composition in the state of Rio de Janeiro (RJ), southeastern Brazil. We used published data in indexed journals and verified voucher specimens housed in two herpetological collections of the Museu Nacional (UFRJ), and the Laboratory of Reptiles (ZUFRJ). We also confirmed vouchers from Instituto Vital Brazil (IVB) and from the Museum of Comparative Zoology (MCZ). We compiled a list containing 149 species of reptiles, distributed among Testudines (N = 15), Crocodylia (N = 1) and Squamata (N = 133; six amphisbaenians, 38 lizards and 89 snakes). Our results add 20 species to the previous list known for the state. Four species recorded are endemic to the state of Rio de Janeiro (Anolis neglectus, Glaucomastix littoralis, Leposternon scutigerum, and Liolaemus lutzae). We identified that 21 reptile species recorded in RJ state (nearly 15% of the total) are included in some threat category either in the IUCN, Brazilian (ICMBio) or state lists of endangered species. We also report that seven of the reptiles recorded are non-indigenous to the state: Cnemidophorus aff. lemniscatus (= Cnemidophorus cryptus), Anolis sagrei, Trachemys scripta, Trachemys dorbigni, Hemidactylus mabouia, Crotalus durissus terrificus, and Rhinoclemmys punctularia. The checklist presented here provides a comprehensive database for further research on the herpetofauna of the Brazilian Atlantic Forest

Sliding wear behavior of Al2O3-NbC composites obtained by conventional and nonconventional techniques

[EN] This study aims to investigate the dry sliding wear behavior of Al2O3 5vol.%NbC nanocomposite sintered by conventional and spark plasma sintering at temperatures from 1450 to 1600 ºC. The tests were performed using WC 6 wt%Co balls as a counterpart material, a load of 30 and 60 N, a sliding distance of 2000 m and a sliding speed of 0.1 m/s. The consolidation techniques influenced the friction coefficient, wear rates and patterns. Samples tested at 30 N showed better wear resistance than the samples tests with 60 N. The nanocomposites obtained by SPS at 1500 ºC exhibited a lower friction coefficient and wear rate compared to all other materials. The results indicated that Al2O3-NbC nanocomposites show promise as material for cutting tool applications.This work has been financial support by the Brazilian institution CAPES for the project CAPES-PVE A086/2013 (project No 23038.009604/2013-12). A. Borrell acknowledges the Spanish Ministry of Economy and Competitiveness for her Juan de la Cierva-Incorporacion contract (IJCI-2014-19839).Ribeiro-Rodrigues Alecrim, L.; Ferreira, J.; Gutierrez-Gonzalez, C.; Salvador Moya, MD.; Borrell Tomás, MA.; Pallone, E. (2017). Sliding wear behavior of Al2O3-NbC composites obtained by conventional and nonconventional techniques. Tribology International. 110:216-221. https://doi.org/10.1016/j.triboint.2017.02.028S21622111

LZS/Al2O3 nanostructured composites obtained by colloidal processing and spark plasma sintering

[EN] Li2O-SiO2-ZrO2 (LZS) glass-ceramics have high mechanical strength, hardness, resistance to abrasion and chemical attack, but also a high coefficient of thermal expansion (CTE), which can be reduced adding alumina nanoparticles. The conventional glass-ceramic production is relatively complex and energy consuming, since it requires the melting of the raw materials to form a glass frit and a two-step milling process to obtain particle sizes adequate for compaction. This study describes the preparation of LZS glass-ceramics through a colloidal processing approach from mixtures of SiO2 and ZrO2 nanopowders and a Li precursor (lithium acetate obtained by reaction of the carbonate with acetic acid). Concentrated suspensions were freeze-dried to obtain homogeneous mixtures of powders that were pressed (100 MPa) and sintered conventionally and by spark plasma sintering. The effect of the alumina nanoparticles additions on suspensions rheology, sintering behavior and properties such as thermal expansion, thermal conductivity, hardness and Young's modulus were evaluated. (C) 2017 Elsevier Ltd. All rights reserved.This work has been supported by Ministerio de Economia y Competitividad (MINECO) and FEDER Funds under grant No MAT2016-67586-C3-R. Authors greatly acknowledge the financial Support of CAPES in the frame of the International Cooperation Program Science without Borders for Special Visiting Researcher PVE (MEC/MCTI/CAPES/CNPQ/FAPs/No 71/2013), Project no. A011/2013. A. Borrell acknowledges the MINECO for her Juan de la Cierva-Incorporacion contract (IJCI-2014-19839).Arcaro, S.; Novaes De Oliveira, A.; Gutierrez-Gonzalez, C.; Salvador Moya, MD.; Borrell Tomás, MA.; Moreno, R. (2017). LZS/Al2O3 nanostructured composites obtained by colloidal processing and spark plasma sintering. Journal of the European Ceramic Society. 37(16):5139-5148. https://doi.org/10.1016/j.jeurceramsoc.2017.03.023S51395148371

Correlation effects and the high-frequency spin susceptibility of an electron liquid: Exact limits

Spin correlations in an interacting electron liquid are studied in the high-frequency limit and in both two and three dimensions. The third-moment sum rule is evaluated and used to derive exact limiting forms (at both long- and short-wavelengths) for the spin-antisymmetric local-field factor, $\lim_{\omega \to \infty}G_-({\bf q, \omega})$. In two dimensions $\lim_{\omega \to \infty}G_-({\bf q, \omega})$ is found to diverge as $1/q$ at long wavelengths, and the spin-antisymmetric exchange-correlation kernel of time-dependent spin density functional theory diverges as $1/q^2$ in both two and three dimensions. These signal a failure of the local-density approximation, one that can be redressed by alternative approaches.Comment: 5 page

Event Shape/Energy Flow Correlations

We introduce a set of correlations between energy flow and event shapes that are sensitive to the flow of color at short distances in jet events. These correlations are formulated for a general set of event shapes, which includes jet broadening and thrust as special cases. We illustrate the method for electron-positron annihilation dijet events, and calculate the correlation at leading logarithm in the energy flow and at next-to-leading-logarithm in the event shape.Comment: 43 pages, eight eps figures; minor changes, references adde

Lorentz breaking Effective Field Theory and observational tests

Analogue models of gravity have provided an experimentally realizable test field for our ideas on quantum field theory in curved spacetimes but they have also inspired the investigation of possible departures from exact Lorentz invariance at microscopic scales. In this role they have joined, and sometime anticipated, several quantum gravity models characterized by Lorentz breaking phenomenology. A crucial difference between these speculations and other ones associated to quantum gravity scenarios, is the possibility to carry out observational and experimental tests which have nowadays led to a broad range of constraints on departures from Lorentz invariance. We shall review here the effective field theory approach to Lorentz breaking in the matter sector, present the constraints provided by the available observations and finally discuss the implications of the persisting uncertainty on the composition of the ultra high energy cosmic rays for the constraints on the higher order, analogue gravity inspired, Lorentz violations.Comment: 47 pages, 4 figures. Lecture Notes for the IX SIGRAV School on "Analogue Gravity", Como (Italy), May 2011. V.3. Typo corrected, references adde

Six Years of Chandra Observations of Supernova Remnants

We present a review of the first six years of Chandra X-ray Observatory observations of supernova remnants. From the official "first-light" observation of Cassiopeia A that revealed for the first time the compact remnant of the explosion, to the recent million-second spectrally-resolved observation that revealed new details of the stellar composition and dynamics of the original explosion, Chandra observations have provided new insights into the supernova phenomenon. We present an admittedly biased overview of six years of these observations, highlighting new discoveries made possible by Chandra's unique capabilities.Comment: 82 pages, 28 figures, for the book Astrophysics Update

Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV

We present the first measurement of directed flow ($v_1$) at RHIC. $v_1$ is found to be consistent with zero at pseudorapidities $\eta$ from -1.2 to 1.2, then rises to the level of a couple of percent over the range $2.4 < |\eta| < 4$. The latter observation is similar to data from NA49 if the SPS rapidities are shifted by the difference in beam rapidity between RHIC and SPS. Back-to-back jets emitted out-of-plane are found to be suppressed more if compared to those emitted in-plane, which is consistent with {\it jet quenching}. Using the scalar product method, we systematically compared azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure

Azimuthal anisotropy: the higher harmonics

We report the first observations of the fourth harmonic (v_4) in the azimuthal distribution of particles at RHIC. The measurement was done taking advantage of the large elliptic flow generated at RHIC. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding

Plasma Wakefield Acceleration with a Modulated Proton Bunch

The plasma wakefield amplitudes which could be achieved via the modulation of a long proton bunch are investigated. We find that in the limit of long bunches compared to the plasma wavelength, the strength of the accelerating fields is directly proportional to the number of particles in the drive bunch and inversely proportional to the square of the transverse bunch size. The scaling laws were tested and verified in detailed simulations using parameters of existing proton accelerators, and large electric fields were achieved, reaching 1 GV/m for LHC bunches. Energy gains for test electrons beyond 6 TeV were found in this case.Comment: 9 pages, 7 figure