437 research outputs found
Finite density phase transition of QCD with and using canonical ensemble method
In a progress toward searching for the QCD critical point, we study the
finite density phase transition of and 2 lattice QCD at finite
temperature with the canonical ensemble approach. We develop a winding number
expansion method to accurately project out the particle number from the fermion
determinant which greatly extends the applicable range of baryon number sectors
to make the study feasible. Our lattice simulation was carried out with the
clover fermions and improved gauge action. For a given temperature, we
calculate the baryon chemical potential from the canonical approach to look for
the mixed phase as a signal for the first order phase transition. In the case
of , we observe an "S-shape" structure in the chemical potential-density
plane due to the surface tension of the mixed phase in a finite volume which is
a signal for the first order phase transition. We use the Maxwell construction
to determine the phase boundaries for three temperatures below . The
intersecting point of the two extrapolated boundaries turns out to be at the
expected first order transition point at with . This serves as a
check for our method of identifying the critical point. We also studied the
case, but do not see a signal of the mixed phase for temperature as
low as 0.83 .Comment: 28 pages, 11 figures,references added, final versio
Effects of stress-dose hydrocortisone therapy in septic shock (part II): soluble E-selectin and interleukin-6. Preliminary results of a double blinded, randomized, placebo-controlled cross-over study
Effects of stress-dose hydrocortisone therapy in septic shock (part III): monocyte HLA-DR expression and blood interferon-? concentration. Preliminary results of a double blinded, randomized, placebo-controlled cross-over study
Effects of hydrocortisone stress-dose therapy in septic shock (part I): influence on hemodynamic stability and plasma nitrite/nitrate levels
Evaluando el progreso de la eficiencia con tecnología en una cadena de hoteles española
This paper analyzes the changes in the total factor productivity index of a Spanish hotel chain in the
period from 2007 to 2010 with the purpose of identifying efficiency patterns for the chain in a period of
financial crisis. The data envelopment analysis (DEA) Malmquist productivity index was used to estimate
productivity change in 38 hotels of the AC chain. Results reveal AC hotels’ efficiency trends and,
therefore, their competitiveness in the recession period; they also show the changes experienced in
these hotels’ total productivity and its components: technological and efficiency changes. Positive
efficiency changes were due to positive technical efficiency rather than technological efficiency. The
recession period certainly influenced the performance of AC Hotels, which focused on organizational
changes rather than investing in technology.Este artigo analisa as mudanças no fator total de produtividade de uma cadeia de hotéis na Espanha,
no período de 2007-2010, com o propósito de identificar os padrões da cadeia em um período
de crise financeira. O índice data envelopment analysis (DEA) Malmquist de produtividade foi usado
para estimar a mudança da produtividade nos 38 hotéis da AC Cadeia de Hotéis. Os resultados revelaram
as tendências de eficiência e competitividade da AC Hotéis em um período de recessão, bem
como as mudanças vivenciadas na produtividade total e, consequentemente, em seus componentes
de eficiência e tecnológicos. O período de recessão influenciou, sem dúvida, o comportamento da AC
Hotéis, que buscou mais mudanças organizacionais do que tecnológicas.Este artículo analiza los cambios del índice de productividad del factor total de una cadena de hoteles
españoles en el periodo de 2007 hasta 2010, con el propósito de identificar patrones de eficiencia
para la cadena en un periodo de crisis financiera. El índice de productividad data envelopment analysis
(DEA) Malmquist fue utilizado para estimar el cambio de productividad en 38 hoteles de la cadena
AC. Los resultados revelan las tendencias de la eficiencia de los hoteles AC y, por lo tanto, su competitividad
en el periodo de recisión; ellos también demuestran los cambios experimentados en la
productividad total de eses hoteles y sus componentes: cambios de eficiencia y tecnológicos. Cambios
de eficiencia positivos se debieron más bien a eficiencias técnicas positivas que a eficiencias tecnológicas.
El periodo de recesión ciertamente ha influenciado los Hoteles AC, que enfocaron más en los
cambios organizacionales que en invirtiendo en tecnología
and Pseudoscalar Form Factors from Lattice QCD
The form factor is obtained from a quenched
lattice QCD calculation of the pseudoscalar form factor of the
proton with pion pole dominance. We find that fitted with the
monopole form agrees well with the Goldberger-Treiman relation and is much
preferred over the dipole form. The monopole mass is determined to be which shows that is rather soft. The
extrapolated coupling constant is quite
consistent with the phenomenological values. We also compare
with the axial form factor to check the pion dominance in the
induced pseudoscalar form factor vis \`{a} vis chiral Ward identity.Comment: 8 pages of text plus 4 postscript figures (128 kbytes
Search for tau -> e gamma decay at Belle
We have searched for the lepton-flavor-violating decay tau -> e gamma using a
data sample of 86.7/fb collected with the Belle detector at the KEKB asymmetric
e^+ e^- collider. No evidence for a signal is obtained, and we set an upper
limit for the branching fraction Br(tau -> e gamma) < 3.9 x 10^-7 at the 90%
C.L.Comment: 11 pages, 10 figures, ReVTeX4, eps
Hydrodynamic slip can align thin nanoplatelets in shear flow
The large-scale processing of nanomaterials such as graphene and MoS2 relies on understanding the flow behaviour of nanometrically-thin platelets suspended in liquids. Here we show, by combining non-equilibrium molecular dynamics and continuum simulations, that rigid nanoplatelets can attain a stable orientation for sufficiently strong flows. Such a stable orientation is in contradiction with the rotational motion predicted by classical colloidal hydrodynamics. This surprising effect is due to hydrodynamic slip at the liquid-solid interface and occurs when the slip length is larger than the platelet thickness; a slip length of a few nanometers may be sufficient to observe alignment. The predictions we developed by examining pure and surface-modified graphene is applicable to different solvent/2D material combinations. The emergence of a fixed orientation in a direction nearly parallel to the flow implies a slip-dependent change in several macroscopic transport properties, with potential impact on applications ranging from functional inks to nanocomposites.Energy Technolog
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Biomineralisation by earthworms: an investigation into the stability and distribution of amorphous calcium carbonate
Background
Many biominerals form from amorphous calcium carbonate (ACC), but this phase is highly unstable when synthesised in its pure form inorganically. Several species of earthworm secrete calcium carbonate granules which contain highly stable ACC. We analysed the milky fluid from which granules form and solid granules for amino acid (by liquid chromatography) and functional group (by Fourier transform infrared (FTIR) spectroscopy) compositions. Granule elemental composition was determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and electron microprobe analysis (EMPA). Mass of ACC present in solid granules was quantified using FTIR and compared to granule elemental and amino acid compositions. Bulk analysis of granules was of powdered bulk material. Spatially resolved analysis was of thin sections of granules using synchrotron-based μ-FTIR and EMPA electron microprobe analysis.
Results
The milky fluid from which granules form is amino acid-rich (≤ 136 ± 3 nmol mg−1 (n = 3; ± std dev) per individual amino acid); the CaCO3 phase present is ACC. Even four years after production, granules contain ACC. No correlation exists between mass of ACC present and granule elemental composition. Granule amino acid concentrations correlate well with ACC content (r ≥ 0.7, p ≤ 0.05) consistent with a role for amino acids (or the proteins they make up) in ACC stabilisation. Intra-granule variation in ACC (RSD = 16%) and amino acid concentration (RSD = 22–35%) was high for granules produced by the same earthworm. Maps of ACC distribution produced using synchrotron-based μ-FTIR mapping of granule thin sections and the relative intensity of the ν2: ν4 peak ratio, cluster analysis and component regression using ACC and calcite standards showed similar spatial distributions of likely ACC-rich and calcite-rich areas. We could not identify organic peaks in the μ-FTIR spectra and thus could not determine whether ACC-rich domains also had relatively high amino acid concentrations. No correlation exists between ACC distribution and elemental concentrations determined by EMPA.
Conclusions
ACC present in earthworm CaCO3 granules is highly stable. Our results suggest a role for amino acids (or proteins) in this stability. We see no evidence for stabilisation of ACC by incorporation of inorganic components
Search For Exotic Tau-decays
The Crystal Ball detector at the Doris II storage ring at DESY was used to search for the exotic decay processes tau -> e gamma, tau -> e pi0, tau -> e eta. No signal was observed. We obtained the following 90% CL upper limits on the branching fractions:B(tau -> e gamma)< 2.0x10^(-4),B(tau -> e pi0) < 1.4x10^(-4),B(tau -> e eta) < 2.4x10^(-4)
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