3,689 research outputs found
Instanton-induced crossover in dense QCD
We study the properties of an instanton ensemble in three-flavor dense QCD
which can be regarded as an instanton plasma weakly interacting by exchanging
the eta' mesons. Based on this description, we explore the chiral phase
transition induced by the instanton ensemble at high baryon density in analogy
with the Berezinskii-Kosterlitz-Thouless transition. Using the renormalization
group approach, we show that the instanton ensemble always behaves as a
screened and unpaired plasma. We also demonstrate that the chiral condensate in
dense QCD is proportional to the instanton density.Comment: 15 pages; version to appear in JHE
Wearable Platform for Automatic Recognition of Parkinson Disease by Muscular Implication Monitoring
The need for diagnostic tools for the characterization of progressive movement disorders - as the Parkinson Disease (PD) - aiming to early detect and monitor the pathology is getting more and more impelling. The parallel request of wearable and wireless solutions, for the real-time monitoring in a non-controlled environment, has led to the implementation of a Quantitative Gait Analysis platform for the extraction of muscular implications features in ordinary motor action, such as gait. The here proposed platform is used for the quantification of PD symptoms. Addressing the wearable trend, the proposed architecture is able to define the real-time modulation of the muscular indexes by using 8 EMG wireless nodes positioned on lower limbs. The implemented system “translates” the acquisition in a 1-bit signal, exploiting a dynamic thresholding algorithm. The resulting 1-bit signals are used both to define muscular indexes both to drastically reduce the amount of data to be analyzed, preserving at the same time the muscular information. The overall architecture has been fully implemented on Altera Cyclone V FPGA. The system has been tested on 4 subjects: 2 affected by PD and 2 healthy subjects (control group). The experimental results highlight the validity of the proposed solution in Disease recognition and the outcomes match the clinical literature results
Global Attractivity in a Second-Order Nonlinear Difference Equation
AbstractConsider the difference equation xn+1 = xnƒ(xn−1), n = 0, 1, 2, ..., (1) where the function ƒ satisfies the following conditions:•ƒ ∈ [[0, ∞), (0, ∞)] and ƒ() is nonincreasing in ;•The equation ƒ() = 1 has a unique positive solution;•If denotes the unique positive solution of ƒ() = 1, then
[xƒ(x) − x](x − x) > 0 for x ≠ x Then x is a global attractor of all positive solutions of Eq. (1)
Mass corrections in decay and the role of distribution amplitudes
We consider mass correction effects on the polar angular distribution of a
baryon--antibaryon pair created in the chain decay process , generalizing a previous analysis of Carimalo. We show the
relevance of the features of the baryon distribution amplitudes and estimate
the electromagnetic corrections to the QCD results.Comment: 26 pages + 3 figures, REVTEX 3.0, figures appended as uuencoded,
tar-compressed postscript fil
Moderate deviations for the determinant of Wigner matrices
We establish a moderate deviations principle (MDP) for the log-determinant
of a Wigner matrix matching four moments with
either the GUE or GOE ensemble. Further we establish Cram\'er--type moderate
deviations and Berry-Esseen bounds for the log-determinant for the GUE and GOE
ensembles as well as for non-symmetric and non-Hermitian Gaussian random
matrices (Ginibre ensembles), respectively.Comment: 20 pages, one missing reference added; Limit Theorems in Probability,
Statistics and Number Theory, Springer Proceedings in Mathematics and
Statistics, 201
Superhard Phases of Simple Substances and Binary Compounds of the B-C-N-O System: from Diamond to the Latest Results (a Review)
The basic known and hypothetic one- and two-element phases of the B-C-N-O
system (both superhard phases having diamond and boron structures and
precursors to synthesize them) are described. The attention has been given to
the structure, basic mechanical properties, and methods to identify and
characterize the materials. For some phases that have been recently described
in the literature the synthesis conditions at high pressures and temperatures
are indicated.Comment: Review on superhard B-C-N-O phase
Pion Decay Constant at Finite Temperature in the Nonlinear Sigma Model
We calculate the pion decay constant near the critical temperature of the
nonlinear sigma model in the large limit. Making use of the known
low temperature behavior, we construct a Pad\'{e} approximant to obtain the
behavior of at all temperatures.Comment: 8 pages, one latex file and one postscript file (uses psfig).
Uuencode
Transformación de arsénico por bacterias aisladas de sedimentos enriquecidos con el metaloide
Las bacterias presentes en ambientes contaminados con arsénico son capaces de resistir esta presión ambiental y adaptarse mediante mecanismos de resistencia, lo que involucra, entre otros, la oxidación y/o reducción del metaloide. El objetivo del presente trabajo fue investigar las propiedades redox en bacterias tolerantes a arsénico, aisladas de sedimentos naturales. Los sedimentos se obtuvieron del río Camarones(I región, Chile). Las muestras se incubaron en medio mineral durante 7 días, a temperatura ambiente. Diluciones apropiadas fueron sembradas en agar R2A se incubaron a 25 ºC, hasta 7 días. Los niveles de tolerancia para cada metal se determinaron mediante dilución seriada en placa. La propiedad de oxidar o reducir arsénico se investigó mediante nitrato de plata. Los resultados muestran la presencia de bacterias resistentes a arsenito y arseniato, con niveles de tolerancia > 8mM. El 36,84% de las cepas aisladas de sedimentos ricos en arsénico presentaron actividades reductoras(>50%). En cambio, en bacterias aisladas de sedimentoscon bajas concentraciones del metaloide, la actividad reductora varió entre un 10% y 25%. Se puede concluir que la presencia de arsénico selecciona bacterias con la capacidad de tolerar concentraciones altas de arsénico a través de la transformación de As(V) en As(III)
Gapless Fermions and Quantum Order
Using 2D quantum spin-1/2 model as a concrete example, we studied the
relation between gapless fermionic excitations (spinons) and quantum orders in
some spin liquid states. Using winding number, we find the projective symmetry
group that characterizes the quantum order directly determines the pattern of
Fermi points in the Brillouin zone. Thus quantum orders provide an origin for
gapless fermionic excitations.Comment: 23 pages. LaTeX. Homepage http://dao.mit.edu/~we
Two-Loop Self-Energy and Multiple Scattering at Finite Temperature
One and two loop self-energies are worked out explicitly for a heavy scalar
field interacting weakly with a light self-interacting scalar field at finite
temperature. The ring/daisy diagrams and a set of necklace diagrams can be
summed simultaneously. This simple model serves to illustrate the connection
between multi-loop self-energy diagrams and multiple scattering in a medium.Comment: 15 pages including 7 figures; v2. with appendix added, accepted by
PR
- …