Checklist of lizards and amphisbaenians of Argentina: an update

We update the list of lizards of Argentina, reporting a total of 261 species from the country, arranged in 27 genera and 10 families. Introduced species and dubious or erroneous records are discussed. Taxonomic, nomenclatural and distributional comments are provided when required. Considering species of probable occurrence in the country (known to occur in Bolivia, Brazil, Chile and Paraguay at localities very close to the Argentinean border) and still undescribed taxa, we estimate that the total number of species in Argentina could exceed 300 in the next few years.Fil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Martinez, L.e.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Morando, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Comparison of Microstructures and Mechanical Properties for Solid Cobalt-Base Alloy Components and Biomedical Implant Prototypes Fabricated by Electron Beam Melting

The microstructures and mechanical behavior of simple, as-fabricated, solid geometries (with a density of 8.4 g/cm3), as-fabricated and fabricated and annealed femoral (knee) prototypes all produced by additive manufacturing (AM) using electron beam melting (EBM) of Co-26Cr-6Mo-0.2C powder are examined and compared in this study. Microstructures and microstructural issues are examined by optical metallography, SEM, TEM, EDS, and XRD while mechanical properties included selective specimen tensile testing and Vickers microindentation (HV) and Rockwell C-scale (HRC) hardness measurements. Orthogonal (X-Y) melt scanning of the electron beam during AM produced unique, orthogonal and related Cr23C6 carbide (precipitate) cellular arrays with dimensions of ~2μm in the build plane perpendicular to the build direction, while connected carbide columns were formed in the vertical plane, parallel to the build direction.Mechanical Engineerin

Microstructure Architecture Development in Metals and Alloys By Additive Manufacturing Using Electron Beam Melting

The concept of materials with controlled microstructural architecture (MCMA) to develop and fabricate structural materials with novel and possibly superior properties and performance characteristics is a new paradigm or paradigm extension for materials science and engineering. In the conventional materials science and engineering paradigm, structure (microstructure), properties, processing, and performance features are linked in the development of desirable materials properties and performance through processing methodologies which manipulate microstructures. For many metal or alloy systems, thermomechanical treatment combining controlled amounts of plastic deformation with heat treatment or aging cycles can achieve improved mechanical properties beyond those attainable by conventional processing alone (such as rolling or forging for example) through controlled microstructure development. In this paper we illustrate a new concept involving the fabrication of microstructural architectures by the process development and selective manipulation of these microstructures ideally defining material design space. This allows for the additional or independent manipulation of material properties by additive manufacturing (AM) using electron beam melting (EBM). Specifically we demonstrate the novel development of a carbide (M23C6) architecture in the AM of a Co-base alloy and an oxide (Cu2O) precipitate-dislocation architecture in the AM of an oxygen-containing Cu. While more conventional processing can produce various precipitate microstructures in these materials, EBM produces spatial arrays of precipitate columns or columnar-like features often oriented in the build direction. These microstructural architectures are observed by optical microscopy and scanning and transmission electron microscopy. Prospects for EBM architecture development in precipitation-hardenable Al alloys is also discussed. In the EBM build process using precursor powders, the electron beam parameters (including beam focus, scan speed and sequencing) produce localized, requisite thermodynamic regimes which create or organize the precipitate-related spatial arrays. This feature demonstrates the utility of AM not only in the fabrication of complex components, but also prospects for selective property design using CAD for MCMA development: a new or extended processing-microstructure-property-performance paradigm for materials science and engineering in advanced manufacturing involving solid free-form fabrication (SFF).Mechanical Engineerin

Effect of Build Parameters and Build Geometries on Residual Microstructures and Mechanical Properties of Ti-6Al-4V Components Built by Electron Beam Melting (EBM)

In this study, involving additive manufacturing (AM) using electron beam melting (EBM), we have examined build defects which result from beam tripping, porosities (including unmelted or unsintered zones) due to excursions from optimal build parameters (especially variations in melt scan beam current and scan speed), and gas bubbles trapped in atomized Ti-6Al-4V starting powder as well as recycled powder, and retained in the build. At optimized build conditions we have also examined microstructure-mechanical property (hardness, tensile strength, and elongation) variations for multiple rake building and multiple melt scans using optical metallography and scanning and transmission electron microscopy (SEM and TEM). These build variances cause cooling rate variances which promote α-phase growth and variations in dislocation density, as well as α-to-α' (martensite) phase changes, all of which produce some degree of mechanical property variations. These features (especially α-to-α' phase changes) are notable on comparing solid builds in comparison with a variety of mesh arrays where strut dimension and build-element complexities alter the cooling rates in a significant way. We illustrate these microstructure variations with corresponding variations in microindentation hardness measurements made directly on fine mesh (strut) structures. Finally, we have examined Ti-6Al-4V powder chemistries and solid build chemistries which for single-pass melt scans at optimized build conditions are shown to be relatively constant up to 40 cycles of powder reuse with the exception of Al content which was reduced by 10 to 15% in solid builds at optimized conditions. However, Al loss in solid builds approached 25% for multiple (2 and 3) melt scans, while no changes in Ar gas-bubble density were observed with changes in α-phase (grain) width which increased from 3 µm for a single melt scan to 4.5 and 6 µm for 2 and 3 melt scans, respectively. Corresponding Rockwell C-scale (HRC) hardness varied from 37, 36, and 35, respectively; with ultimate tensile strengths exceeding 1.2 GPa at elongations of 12% or higher for this melt scan sequence.Mechanical Engineerin

Transmission Properties of the oscillating delta-function potential

We derive an exact expression for the transmission amplitude of a particle moving through a harmonically driven delta-function potential by using the method of continued-fractions within the framework of Floquet theory. We prove that the transmission through this potential as a function of the incident energy presents at most two real zeros, that its poles occur at energies $n\hbar\omega+\varepsilon^*$ ($0<Re(\varepsilon^*)<\hbar\omega$), and that the poles and zeros in the transmission amplitude come in pairs with the distance between the zeros and the poles (and their residue) decreasing with increasing energy of the incident particle. We also show the existence of non-resonant "bands" in the transmission amplitude as a function of the strength of the potential and the driving frequency.Comment: 21 pages, 12 figures, 1 tabl

Indirect Dark Matter Detection from Dwarf Satellites: Joint Expectations from Astrophysics and Supersymmetry

We present a general methodology for determining the gamma-ray flux from annihilation of dark matter particles in Milky Way satellite galaxies, focusing on two promising satellites as examples: Segue 1 and Draco. We use the SuperBayeS code to explore the best-fitting regions of the Constrained Minimal Supersymmetric Standard Model (CMSSM) parameter space, and an independent MCMC analysis of the dark matter halo properties of the satellites using published radial velocities. We present a formalism for determining the boost from halo substructure in these galaxies and show that its value depends strongly on the extrapolation of the concentration-mass (c(M)) relation for CDM subhalos down to the minimum possible mass. We show that the preferred region for this minimum halo mass within the CMSSM with neutralino dark matter is ~10^-9-10^-6 solar masses. For the boost model where the observed power-law c(M) relation is extrapolated down to the minimum halo mass we find average boosts of about 20, while the Bullock et al (2001) c(M) model results in boosts of order unity. We estimate that for the power-law c(M) boost model and photon energies greater than a GeV, the Fermi space-telescope has about 20% chance of detecting a dark matter annihilation signal from Draco with signal-to-noise greater than 3 after about 5 years of observation

SUPEROVULAÇÃO OVARIANA E PRODUÇÃO DE EMBRIÕES EM Bubalus bubalis

The aim of the present research work was to optimize ovarian superovulation rate and the embryo production in Murrah and Mediterranean buffaloes around the 60th day after parturition. Fourteen animals were divided in two groups of 7 animals each, G1 (treated animals) and G2 (untreated animals). All animals were subjected to a step of oestrus synchronization by receiving at the 0 day (OD) a vaginal pressary with progestagen (CIDR-B, Intervet), followed by the administration, in the morning of the day 1 (D1), of 3 mg stradiol benzoate IM (Estrogin, Farmavet, SP). The ovarian superovulation (SO) was carried out daily, at intervals of 12 hours in the morning and the afternoon by means of the administration of follicule stimulant hormone (FSH) (Pluset, Serono, Italy) in both groups of experimental animals, during four days according to the following protocol: at the 6th day, 75 IU; at the 7th day, 40 IU; at the 8th day, 30 IU; and at the 9th day, 20 IU. At the afternoon of the 8th day, administration of 500 µg of cloprostenol IM (Closin-Schering-Plough) was performed followed by the withdraw of the vaginal pessaries from all animals. Then, observations on the estrus of the experimental animals has been carried out. For this purpose the animals were inseminated twice at intervals of 12 hours. Additionaly, all animals from the G1, together with the first artificial insemination (AI) received a dose of 3000 UI of gonadotrophic chorionic hormone (GCH) (Vetecor, Calier, IV) while the G2 animals received 1 ml of saline as placebo. All animals from both G1 and G2 groups had their ovaries monitored by ultrasonography from the first day of the AI up to the day when they had their embryos collected. Ultrasography has been carried out by means of an Aloka SSD-550 (Japan) instrument aiming to evaluate the follicles, the ovulation, and the corpora lutea. At the 5.5th after the estrus observation a washing of the uterine cornus has been carried out for the embryos harvesting and evaluation. According to the present experiment, it was possible to conclude that the protocol used to promote superovulation (SO) in buffaloes by means of FSH showed to be efficient resulting in the production of significant number of antral follicles larger than 8.0 mm diameter at the estrus day and that the gonadotropohic corionic hormone showed significant efficiency by displaying larger percentual ovulations in the treated group (pO presente estudo objetivou otimizar a superovulação ovariana, a taxa de ovulação e a produção de embriões em búfalas. Os animais eram da raça Murrah e Mediterrâneo e estavam em torno do 60º dia pós parto. Quatorze animais foram divididos em dois grupos, sendo um grupo tratado (G1=7 animais) e outro não-tratado (G2=7 animais). Todos os animais foram submetidos à sincronização do estro, recebendo no dia 0 (D0) um pessário vaginal com progestágeno (CIDR-B, Intervet); no dia 1 (D1) pela manhã foi aplicado 3 mg de benzoato de estradiol IM (Estrogin Farmavet, SP). A superovulação ovariana (SO) foi executada pela manhã e à tarde com hormônio folículo estimulante (FSH)(Pluset, Serono, Itália)), administrado diariamente a intervalo de 12 horas entre cada aplicação, durante quatro dias seguidos nos dois grupos, conforme o protocolo: dia 6, 75 UI; dia 7, 40 UI; dia 8, 30 UI; dia 9, 20 UI. No dia 8 à tarde administrou-se 500 microgramas de cloprostenol IM (Ciosin - Schering-Plough) e em seguida houve a retirada dos pessários vaginais de todos os animais. Na sequência, foram feitas as observações de cio; os animais foram inseminados duas vezes a intervalos de 12 horas um do outro. Adicionalmente, o G1 recebeu junto com a 1ª inseminação artificial (IA), uma dose de 3000 UI de hormônio coriônico gonadotrófico (hCG) (Vetecor, Calier, IV) e o G2 recebeu 1 ml de solução fisiológica, como placebo. Todos os animais tiveram os ovários monitorados mediante ultrassonografia, desde o dia da 1ª IA até o dia da coleta dos embriões, mediante aparelho Aloka SSD-550 (Japão), visando a avaliação de folículos, ovulação e corpos lúteos. No 5,5º dia pós a observação de cio, procedeu-se às lavagens dos cornos uterinos para a colheita dos embriões e avaliação. Concluiu-se que o protocolo utilizado para SO em bubalinos com FSH, foi eficiente, ao promover significativo numero de folículos antrais maiores que 8,0 mm de diâmetro no dia do cio e que o hCG mostrou-se significativamente eficiente, pois proporcionou maior % de ovulações no grupo tratado (

Influence of chronic ocular hypertension on emmetropia: Refractive, structural and functional study in two rat models

Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

On the Exact Evaluation of Certain Instances of the Potts Partition Function by Quantum Computers

We present an efficient quantum algorithm for the exact evaluation of either the fully ferromagnetic or anti-ferromagnetic q-state Potts partition function Z for a family of graphs related to irreducible cyclic codes. This problem is related to the evaluation of the Jones and Tutte polynomials. We consider the connection between the weight enumerator polynomial from coding theory and Z and exploit the fact that there exists a quantum algorithm for efficiently estimating Gauss sums in order to obtain the weight enumerator for a certain class of linear codes. In this way we demonstrate that for a certain class of sparse graphs, which we call Irreducible Cyclic Cocycle Code (ICCC_\epsilon) graphs, quantum computers provide a polynomial speed up in the difference between the number of edges and vertices of the graph, and an exponential speed up in q, over the best classical algorithms known to date

A novel determination of the local dark matter density

We present a novel study on the problem of constructing mass models for the Milky Way, concentrating on features regarding the dark matter halo component. We have considered a variegated sample of dynamical observables for the Galaxy, including several results which have appeared recently, and studied a 7- or 8-dimensional parameter space - defining the Galaxy model - by implementing a Bayesian approach to the parameter estimation based on a Markov Chain Monte Carlo method. The main result of this analysis is a novel determination of the local dark matter halo density which, assuming spherical symmetry and either an Einasto or an NFW density profile is found to be around 0.39 GeV cm$^{-3}$ with a 1-$\sigma$ error bar of about 7%; more precisely we find a $\rho_{DM}(R_0) = 0.385 \pm 0.027 \rm GeV cm^{-3}$ for the Einasto profile and $\rho_{DM}(R_0) = 0.389 \pm 0.025 \rm GeV cm^{-3}$ for the NFW. This is in contrast to the standard assumption that $\rho_{DM}(R_0)$ is about 0.3 GeV cm$^{-3}$ with an uncertainty of a factor of 2 to 3. A very precise determination of the local halo density is very important for interpreting direct dark matter detection experiments. Indeed the results we produced, together with the recent accurate determination of the local circular velocity, should be very useful to considerably narrow astrophysical uncertainties on direct dark matter detection.Comment: 31 pages,11 figures; minor changes in the text; two figures adde