Systematics of species of the genus Akodon (Rodentia: Sigmodontinae) in southeastern Brazil and implications for the biogeography of the Campos de Altitude

http://deepblue.lib.umich.edu/bitstream/2027.42/111041/1/MP197.pd

Monitoring Single-point Dressers Using Fuzzy Models

AbstractGrinding causes progressive dulling and glazing of the grinding wheel grains and clogging of the voids on the wheel's surface with ground metal dust particles, which gradually increases the grinding forces. The condition of the grains at the periphery of a grinding wheel strongly influences the damage induced in a ground workpiece. Therefore, truing and dressing must be carried out frequently. Dressing is the process of conditioning the grinding wheel surface to reshape the wheel when it has lost its original shape through wear, giving the tool its original condition of efficiency. Despite the very broad range of dressing tools available today, the single-point diamond dresser is still the most widely used dressing tool due to its great versatility. The aim of this work is to predict the wear level of the single-point dresser based on acoustic emission and vibration signals used as input variables for fuzzy models. Experimental tests were performed with synthetic diamond dressers on a surface-grinding machine equipped with an aluminum oxide grinding wheel. Acoustic emission and vibration sensors were attached to the tool holder and the signals were captured at 2MHz. During the tests, the wear of the diamond tip was measured every 20 passes using a microscope with 10 to 100 X magnification. A study was conducted of the frequency content of the signals, choosing the frequency bands that best correlate with the diamond's wear. Digital band-pass filters were applied to the raw signals, after which two statistics were calculated to serve as the inputs for the fuzzy models. The results indicate that the fuzzy models using the aforementioned signal statistics are highly effective for predicting the wear level of the dresser

Local convergence analysis of the Gauss–Newton method under a majorant condition

AbstractThe Gauss–Newton method for solving nonlinear least squares problems is studied in this paper. Under the hypothesis that the derivative of the function associated with the least square problem satisfies a majorant condition, a local convergence analysis is presented. This analysis allows us to obtain the optimal convergence radius and the biggest range for the uniqueness of stationary point, and to unify two previous and unrelated results

Galerkin Method in the Gravitational Collapse: a Dynamical System Approach

We study the general dynamics of the spherically symmetric gravitational collapse of a massless scalar field. We apply the Galerkin projection method to transform a system of partial differential equations into a set of ordinary differential equations for modal coefficients, after a convenient truncation procedure, largely applied to problems of turbulence. In the present case, we have generated a finite dynamical system that reproduces the essential features of the dynamics of the gravitational collapse, even for a lower order of truncation. Each initial condition in the space of modal coefficients corresponds to a well definite spatial distribution of scalar field. Numerical experiments with the dynamical system show that depending on the strength of the scalar field packet, the formation of black-holes or the dispersion of the scalar field leaving behind flat spacetime are the two main outcomes. We also found numerical evidence that between both asymptotic states, there is a critical solution represented by a limit cycle in the modal space with period $\Delta u \approx 3.55$.Comment: 9 pages, revtex4, 10 ps figures; Phys. Rev. D, in pres

Billion-atom Synchronous Parallel Kinetic Monte Carlo Simulations of Critical 3D Ising Systems

An extension of the synchronous parallel kinetic Monte Carlo (pkMC) algorithm developed by Martinez {\it et al} [{\it J.\ Comp.\ Phys.} {\bf 227} (2008) 3804] to discrete lattices is presented. The method solves the master equation synchronously by recourse to null events that keep all processors time clocks current in a global sense. Boundary conflicts are rigorously solved by adopting a chessboard decomposition into non-interacting sublattices. We find that the bias introduced by the spatial correlations attendant to the sublattice decomposition is within the standard deviation of the serial method, which confirms the statistical validity of the method. We have assessed the parallel efficiency of the method and find that our algorithm scales consistently with problem size and sublattice partition. We apply the method to the calculation of scale-dependent critical exponents in billion-atom 3D Ising systems, with very good agreement with state-of-the-art multispin simulations

Systematics of species of the genus Akodon (Rodentia: Sigmodontinae) in southeastern Brazil and implications for the biogeography of the Campos de Altitude.

Faunal inventories of the highest peaks of the Atlantic forests of South America, in the Caparaó and Itatiaia mountain ranges in Southeastern Brazil, have revealed a new community of small mammals. The species making up this community appear to be restricted to the highest altitudinal zones and are found in close association with scattered montane grasslands (campos de altitude). Their phylogenetic relationships can provide insights into speciation in mountaintop communities of the Atlantic forest. In this paper we review the taxonomic identity and systematic relationships of Akodon mystax, a high- altitude endemic described from Caparaó. We demonstrate that populations from Itatiaia previously assigned to mystax are morphologically, cytogenetically and genetically distinct from that species and appear to represent a northern isolate of Akodon paranaensis, and that Akodon mystax is closely related to Akodon lindberghi from the Central Brazilian grasslands. Phylogenetic relationships among these populations demonstrate that differentiation of the mountaintop endemics of Caparaó and Itatiaia is not solely attributable the isolation of campos de altitude from southern grasslands of Brazil and Uruguay as grasslands retreated southward, phylogenetic analyses of some groups suggest connections between the campos de altitude and Central Brazil."http://deepblue.lib.umich.edu/bitstream/2027.42/102734/1/MP197.pd

Emissary Foramens Of The Human Skull: Anatomical Characteristics And Its Relations With Clinical Neurosurgery [forámenes Emisarios Del Cráneo Humano: Características Anatómicas Y Sus Relaciones Con La Neurocirugía Clínica]

The recognition of emissary foramens is important not only for understanding the regional neurovascular anatomy, but also to distinguish normal from potentially abnormal structures. Thus, the aim of this study was to review the literature on anatomical and clinical aspects of the mastoid, parietal and sphenoid emissary foramens. It was found that the emissary foramen presents importance in clinical practice because it acts as a route of spread of extracranial infection to the intracranial structures and also possible complications in neurosurgery, due to its influence in the performance of techniques such as radiofrequency rhizotomy for treatment of trigeminal neuralgia. The anatomical knowledge of the emissary foramens is important due to variability in their incidence in the human skull and its relation to the dura mater sinuses.311287292Bergman, R.A., Afifi, A.K., Miyauchi, R., (1995) Illustrated Encyclopedia of Human Anatomic Variation: Opus V: Skeletal systems: CraniumBoyd, G.I., Emissary foramina of cranium in man and the anthropoids (1930) J. Anat., 65, pp. 108-121Casella, A.M.B., Monteiro, M.L.R., Rgensteiner, D.B.W., Caldeira, J.B.F., Regeneração aberrante do nervo do oculomotor após tromboflebite do seio cavernoso (1998) Arq. Bras. Oftalmol., 51, pp. 135-137Currarino, G., Normal variants and congenital anomalies in the region of the obelion (1976) Am. J. Roentgenol., 127 (3), pp. 487-494El Kettani, C., Badaoui, R., Fikri, M., Jeanjean, P., Montpellier, D., Tchaoussov, J., Pulmonary edema after venous air embolism during craniotomy (2002) Eur. J. Anaesthesiol., 19, pp. 846-848Falk, D., Evolution of cranial blood drainage in hominids: Enlarged occipital/marginal sinuses and emissary foramina (1986) Am. J. Phys. Anthropol., 70, pp. 311-324Goucha, S., Mnif, M., Bouhala, T., Tenzakhti, F., El Andaloussi, H., Fazaa, B., Hamza, R., Kamoun, M.R., Value of imaging in GAPO syndrome (2002) J. Radiol., 83, pp. 153-156Gözil, R., Kadioglu, D., Calguner, E., Occipital emissary foramen in skulls from Central Anatolia (1995) Act. Anat., 153, pp. 325-326Gray, H., Bannister, L.H., Berry, M., William, P.L., Osteology (1995) Gray's Anatomy., , In. Gray, H.Bannister, L.H.Berry, M. & William, P.L. 38th ed. London: Churchill LivingstoneGupta, N., Ray, B., Ghosh, S., Anatomic characteristics of foramen Vesalius (2005) Kath. Univ. Med. J., 3 (2), pp. 155-158Gusmão, S., Magaldi, M., Arantes, A., Rizotomia trigeminal por radiofrequência para tratamento da neuralgia do trigêmio (2003) Arq. 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Neurosurg., 46 (2), pp. 100-105Lang, J., (1983) Clinical anatomy of the head, neurocranium, orbit and craniocervical region., , Springer, BerlinLouis Jr., R.G., Loukas, M., Wartmann, C.T., Tubbs, R.S., Apaydin, N., Gupta, A.A., Spentzouris, G., Ysique, J.R., Clinical anatomy of the mastoid and occipital emissary veins in a large series (2009) Surg. Radiol. Anat., pp. 31139-31144Mann, R.W., Enlarged parietal foramina and craniosynostosis in an American Indian child (1990) Am. J. Roentgenol., 154 (3), p. 658O'Rahilly, R., Twohig, M.J., Foramina parietalia permagna (1952) Am. J. Roentgenol., 67 (4), pp. 551-561Ramalho, J.C., Sousa-Rodrigues, C.F., Rodas, P.M.M., Lins, C.J.P., Lima, R.L., Neto, E.T.D.L., Neto, J.A.B.S., A incidência e as relações morfométricas do forame emissário do esfenóide em crânios humanos (2007) Int. J. Morphol. (abstract)., 25 (1), p. 145Reis, C., Deshmukh, V., Zabramski, J.M., Crusius, M., Desmuskh, P., Spetzler, R.E., Preul, M.C., Anatomy of the mastoid emissary vein and venous system of the posterior neck region: Neurosurgical implications (2007) Neurosurg., 61, pp. ONS193-ONS201Reymond, J., Charuta, A., Wysocki, J., The morphology and morphometry of the foramina of the greater wing of the human sphenoid bone (2005) Folia Morphol., 64 (3), pp. 188-193Rossi, A.C., Freire, A.R., Prado, F.B., Caria, P.H.F., Botacin, P.R., Morphological characteristics of foramen of Vesalius and its relationship with clinical implications (2010) J. Morphol. Sci., 27 (1), pp. 26-29Shapiro, R., Robinson, F., The foramina of the middle fossa: A phylogenetic, anatomic and pathologic study (1967) Am. J. 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