1,457 research outputs found
Unusual ending of the second dorsal metacarpal artery as proper palmar digital arteries
Background: The proper palmar digital arteries arise infrequently from dorsal metacarpal arteries. This work reports the second dorsal metacarpal artery unusual ending and a vascular variation related to the superficial palmar arch.
Materials and methods: Fresh human upper limbs routine dissection, from a male cadaver, injected with coloured elastomeric material, immersed in 10% formalin.
Results: The second dorsal metacarpal artery presented terminal branches, the index finger medial proper digital palmar artery and the middle finger lateral proper digital palmar artery. At the division point of both terminal branches, the second dorsal metacarpal artery anastomoses with a thin forth common digital palmar artery.
Conclusions: The value of this knowledge about the infrequent vascular dispoÂsition lies in vascularised flaps design using the second dorsal metacarpal artery. (Folia Morphol 2018; 77, 2: 393–396
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
Anomalies, Anomalous U(1)'s and generalized Chern-Simons terms
A detailed analysis of anomalous U(1)'s and their effective couplings is
performed both in field theory and string theory. It is motivated by the
possible relevance of such couplings in particle physics, as well as a
potential signal distinguishing string theory from other UV options. The most
general anomaly related effective action is analyzed and parameterized. It
contains Stuckelberg, axionic and Chern-Simons-like couplings. It is shown that
such couplings are generically non-trivial in orientifold string vacua and are
not in general fixed by anomalies. A similar analysis in quantum field theories
provides similar couplings. The trilinear gauge boson couplings are also
calculated and their phenomenological relevance is advocated. We do not find
qualitative differences between string and field theory in this sector.Comment: 52 pages, 2 eps figures, LaTeX, feynmf & youngtab packages (v2 -
Minor corrections, references added
Hawking-Page Phase Transition of black Dp-branes and R-charged black holes with an IR Cutoff
We show that the confinement-deconfinement phase transition of supersymmetric
Yang-Mills theories with 16 supercharges in various dimensions can be realized
through the Hawking-Page phase transition between the near horizon geometries
of black Dp-branes and BPS Dp-branes by removing a small radius region in the
geometry in order to realize a confinement phase, which generalizes the
Herzog's discussion for the holographic hard-wall AdS/QCD model. Removing a
small radius region in the gravitational dual corresponds to introducing an IR
cutoff in the dual field theory. We also discuss the Hawking-Page phase
transition between thermal , , spaces and R-charged AdS
black holes coming from the spherical reduction of the decoupling limit of
rotating D3-, M2-, and M5- branes in type IIB supergravity and 11 dimensional
supergravity in grand canonical ensembles, where the IR cutoff also plays a
crucial role in the existence of the phase transition.Comment: 34 pages, 18 figures, JHEP3, v2, references added, v3, some
explanations adde
Polarized DIS in N=4 SYM: Where is spin at strong coupling?
Using the AdS/CFT correspondence, we calculate the polarized structure
functions in strongly coupled N=4 supersymmetric Yang-Mills theory deformed in
the infrared. We find that the flavor singlet contribution to the g_1 structure
function is vanishingly small, while the flavor non-singlet contribution shows
the Regge behavior at small-x with an intercept slightly less than 1. We
explicitly check that the latter satisfies the moment sum rule. We discuss the
`spin crisis' problem and suggest that at strong coupling the spin of a hadron
entirely comes from the orbital angular momentum.Comment: 24 page
Black-hole quasinormal modes and scalar glueballs in a finite-temperature AdS/QCD model
We use the holographic AdS/QCD soft-wall model to investigate the spectrum of
scalar glueballs in a finite temperature plasma. In this model, glueballs are
described by a massless scalar field in an AdS_5 black hole with a dilaton
soft-wall background. Using AdS/CFT prescriptions, we compute the boundary
retarded Green's function. The corresponding thermal spectral function shows
quasiparticle peaks at low temperatures. We also compute the quasinormal modes
of the scalar field in the soft-wall black hole geometry. The temperature and
momentum dependences of these modes are analyzed. The positions and widths of
the peaks of the spectral function are related to the frequencies of the
quasinormal modes. Our numerical results are found employing the power series
method and the computation of Breit-Wigner resonances.Comment: Revision: Results unchanged. More discussions on the model and on the
results. References added. 28 pages, 7 figures, 5 table
The Generalized Green-Schwarz Mechanism for Type IIB Orientifolds with D3- and D7-Branes
In this paper, we work out in detail the tadpole cancellation conditions as
well as the generalized Green-Schwarz mechanism for type IIB orientifold
compactifications with D3- and D7-branes. We find that not only the well-known
D3- and D7-tadpole conditions have to be satisfied, but in general also the
vanishing of the induced D5-brane charges leads to a non-trivial constraint. In
fact, for the case the latter condition is important for
the cancellation of chiral anomalies. We also extend our analysis by including
D9- as well as D5-branes and determine the rules for computing the chiral
spectrum of the combined system.Comment: 33+7 pages; 2 figures; v2: references added; v3: published versio
NUTRITIONAL, HYGIENIC, HEALTH AND ORGANOLEPTIC CHARACTERIZATION OF MEAT OF BOVINE BREED PIEMONTESE
The autochthonous "Piemontese" bovine breed is primarily raised for meat due to the high quality of production. The aim of this study was to investigate the microbiological, nutritional and chemical aspects of samples meat from cattle breeding "Piemontese"
The Self Model and the Conception of Biological Identity in Immunology
The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for sixty years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. We suggest that another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity
Analysis of the influence of the different times of polymerization by incandescent light in composite resins by evaluation of its abrasive wear
No mercado atual a qualidade é necessária na fabricação dos produtos. No mercado odontológico, as resinas compostas são cada vez mais utilizadas para substituir materiais tradicionais, como amalgama, nas restaurações estéticas e funcionais, apresentando boa estética e funcionalidade. A composição quÃmica destes materiais é variável e os resultados das reações quÃmicas do processo de polimerização são bastante desconhecidos. O objetivo deste trabalho era medir a resistência do desgaste abrasivo de seis resinas compostas vendidas no mercado brasileiro polimerizadas com tempos de 10, 20 e 40 segundos. O método do disco retificado modificado para aplicações em odontologia foi usado para tornar esta proposta viável. Neste banco de ensaios um disco dinâmico, revestido por porcelana, desgasta um disco estático revestido do tipo de resina que se pretende avaliar, que foi polimerizada durante um tempo pré-estabelecido. Com a determinação do desgaste de material, num determinado tempo, determinava-se a agressividade (capacidade de um material para desgastar outro material) do disco dinâmico sobre o disco estático. Utilizando-se para isso um programa computacional (LabView). Posteriormente era feita a regressão linear dos valores obtidos e determinado o coeficiente angular, utilizado no cálculo de agressividade. Valores elevados de agressividade indicam uma maior agressão do disco dinâmico contra o disco estático. Os resultados mostraram um comportamento variável para cada material que foi polimerizado nos diferentes tempos de polimerização utilizado, mostrando que o método para fazer estudos de desgaste é prático e rápido para testar materiais novos antes da sua utilização.1317787Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Não temIn the current market an increasing quality is demanded to manufacture products. At the odontologic market the composed resins are becoming more and more used to replace old materials, like amalgamates in the aesthetic and functional restorations, since they present a better appearance and easier manuscript. The chemical composition of these materials varies and the results of the chemical reactions of polymerization processes are quite unknown. The aim of this work was to measure the resistance of the abrasive wear of six composed resins sold in Brazilian market when displayed to polymerization periods of 10, 20 and 40 seconds. The grinding disc method appropriated for odontology was used to make this process possible. For this a bank of assays in which a porcelain covered dynamic disc consumes a static disc recovered by the polymerized resin is used to demonstrate the method in a pre-established time. The abrasive wear was determined by the calculation of the aggressiveness (capacity of a material to consume another). This aggressiveness is determined by an initial graph of displacement for time, through the computational method (LabView program). After they have passed through a linear regression the results give as a possibility the angular coefficient, considered a parameter at the calculation of aggressiveness. Higher values of aggressiveness which means a higher aggression suffered by the resin disc indicate worse resistance to the abrasive consuming of this resin in relation to porcelain. The results showed a variable comportment for each material ahead the different polymerization time, which prove the importance in create a practical and fast analyses method to test new materials before their us
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