1,338 research outputs found
Pion Form Factors in Holographic QCD
Using a holographic dual model of QCD, we compute the pion electromagnetic
form factor F_pi(Q^2) in the spacelike momentum transfer region, as well as
pion couplings to vector mesons g_rho^(n) pi pi. Spontaneous and explicit
chiral symmetry breaking are intrinsic features of this particular holographic
model. We consider variants with both ``hard-wall'' and ``soft-wall'' infrared
cutoffs, and find that the F_pi(Q^2) data tend to lie closer to the hard-wall
model predictions, although both are too shallow for large Q^2. By allowing the
parameters of the soft-wall model (originally fixed by observables such as
m_rho) to vary, one finds fits that tend to agree better with F_pi(Q^2). We
also compute the pion charge radius for a variety of parameter
choices, and use the values of f^(n)_rho, g_{rho^(n) pi pi} and m^(n)_rho to
observe the saturation of F_pi(0) by rho poles.Comment: 17 pages, 2 figures, revised fits using consistent normalization of
f_pi. References update
AdS/QCD and Light Front Holography: A New Approximation to QCD
The combination of Anti-de Sitter space (AdS) methods with light-front
holography leads to a semi-classical first approximation to the spectrum and
wavefunctions of meson and baryon light-quark bound states. Starting from the
bound-state Hamiltonian equation of motion in QCD, we derive relativistic
light-front wave equations in terms of an invariant impact variable zeta which
measures the separation of the quark and gluonic constituents within the hadron
at equal light-front time. These equations of motion in physical space-time are
equivalent to the equations of motion which describe the propagation of spin-J
modes in anti--de Sitter (AdS) space. Its eigenvalues give the hadronic
spectrum, and its eigenmodes represent the probability distributions of the
hadronic constituents at a given scale. Applications to the light meson and
baryon spectra are presented. The predicted meson spectrum has a string-theory
Regge form ; i.e., the square of the
eigenmass is linear in both L and n, where n counts the number of nodes of the
wavefunction in the radial variable zeta. The space-like pion and nucleon form
factors are also well reproduced. One thus obtains a remarkable connection
between the description of hadronic modes in AdS space and the Hamiltonian
formulation of QCD in physical space-time quantized on the light-front at fixed
light-front time. The model can be systematically improved by using its
complete orthonormal solutions to diagonalize the full QCD light-front
Hamiltonian or by applying the Lippmann-Schwinger method in order to
systematically include the QCD interaction terms.Comment: Invited talk, presented by SJB at the Fifth International Conference
On Quarks and Nuclear Physics (QNP09), 21-26 Sep 2009, Beijing, China. Figure
update
Rancang Bangun Sistem Informasi Penjadwalan Produksi Berdasarkan Jadwal Pesanan Barang pada PT. Bioli Lestari
Bioli Lestari is one of the company that run manufacturing industry. This company have problems at controlling their production schedule to fulfill customer product orders. The problem arise because their schedule based on raw material which available at the time, not based on costumer order. Production schedule problem cause company can't give information about product finish due to the costumer. Based on problem explained before, a system that can handle customer orders and can make production schedule based on customers order being needed. In this case system use Shortest Processing Time (SPT) as a method to create production schedule, after that system will create production schedule based on customer orders which can help company to answer customers question about product orders finish due and can help company run production process based on customers order
The Clusters AgeS Experiment (CASE). II. The Eclipsing Blue Straggler OGLEGC-228 in the Globular Cluster 47 Tuc
We use photometric and spectroscopic observations of the eclipsing binary
OGLEGC-228 (V228) to derive the masses, radii, and luminosities of the
component stars. Based on measured systemic velocity, proper motion and
distance, the system is a blue straggler member of the globular cluster 47 Tuc.
Our analysis shows that V228 is a semi-detached Algol. We obtain M=1.512 +/-
0.022 Msun, R=1.357 +/- 0.019 Rsun, L=7.02 +/- 0.050 Lsun for the hotter and
more luminous primary component and M=0.200 +/- 0.007 Msun, R=1.238 +/- 0.013
Rsun, L=1.57 +/- 0.09 Lsun for the Roche lobe filling secondary.Comment: 19 pages, 5 figures, AJ, in pres
T2-weighted and diffusion-weighted MRI for discriminating benign from malignant focal liver lesions: Diagnostic abilities of single versus combined interpretations.
NLRC5 promotes transcription of BTN3A1-3 genes and Vγ9Vδ2 T cell-mediated killing
BTN3A molecules-BTN3A1 in particular-emerged as important mediators of Vγ9Vδ2 T cell activation by phosphoantigens. These metabolites can originate from infections, e.g. with Mycobacterium tuberculosis, or by alterations in cellular metabolism. Despite the growing interest in the BTN3A genes and their high expression in immune cells and various cancers, little is known about their transcriptional regulation. Here we show that these genes are induced by NLRC5, a regulator of MHC class I gene transcription, through an atypical regulatory motif found in their promoters. Accordingly, a robust correlation between NLRC5 and BTN3A gene expression was found in healthy, in M. tuberculosis-infected donors' blood cells, and in primary tumors. Moreover, forcing NLRC5 expression promoted Vγ9Vδ2 T-cell-mediated killing of tumor cells in a BTN3A-dependent manner. Altogether, these findings indicate that NLRC5 regulates the expression of BTN3A genes and hence open opportunities to modulate antimicrobial and anticancer immunity
Photometry and Spectroscopy of the Optical Companion to the Pulsar PSR J1740-5340 in the Globular Cluster NGC 6397
We present photometric and spectroscopic observations of the optical
companion to the millisecond radio pulsar PSR J1740-5340 in the globular
cluster NGC 6397. An analysis of the photometric variability in the B, V, and
I-bands indicates an inclination of the system of 43.9+-2.1 degrees if the
optical companion fills its Roche lobe (a semi-detached configuration). The
spectroscopic data show a radial velocity variation with a semi-amplitude of
K=137.2 +- 2.4 km/sec, and a system velocity gamma=17.6 +- 1.5 km/sec,
consistent with cluster membership. We use these results to derive a mass of
the optical companion of M1=0.296 +- 0.034 Msol and M2=1.53 +- 0.19 Msol for
the pulsar. There is evidence for secular change of the amplitude of the
optical light curve of the variable measured over seven years. The change does
not have interpretation and its presence complicates reliable determination of
the absolute parameters of the binary.Comment: 24 pages, 9 figures, submitted to A
Balanced Homodyne Detection of Optical Quantum States at Audio-Band Frequencies and Below
The advent of stable, highly squeezed states of light has generated great
interest in the gravitational wave community as a means for improving the
quantumnoise- limited performance of advanced interferometric detectors. To
confidently measure these squeezed states, it is first necessary to measure the
shot-noise across the frequency band of interest. Technical noise, such as
non-stationary events, beam pointing, and parasitic interference, can corrupt
shot-noise measurements at low Fourier frequencies, below tens of kilo-Hertz.
In this paper we present a qualitative investigation into all of the relevant
noise sources and the methods by which they can be identified and mitigated in
order to achieve quantum noise limited balanced homodyne detection. Using these
techniques, flat shot-noise down to Fourier frequencies below 0.5 Hz is
produced. This enables the direct observation of large magnitudes of squeezing
across the entire audio-band, of particular interest for ground-based
interferometric gravitational wave detectors. 11.6 dB of shot-noise suppression
is directly observed, with more than 10 dB down to 10 Hz.Comment: 16 pages, 11 figure
Whole-body diffusion-weighted magnetic resonance imaging versus FDG-PET/CT for initial lymphoma staging: systematic review on diagnostic test accuracy studies
Association between Carotid Plaque Characteristics and Cerebral White Matter Lesions: One-Year Follow-Up Study by MRI
Objective: To prospectively assess the relation between carotid plaque characteristics and the development of new cerebral white matter lesions (WMLs) at MRI. Methods: Fifty TIA/stroke patients with ipsilateral 30-69% carotid stenosis underwent MRI of the plaque at baseline. Total plaque volume and markers of vulnerability to thromboembolism (lipid-rich necrotic core [LRNC] volume, fibrous cap [FC] status, and presence of intraplaque hemorrhage [IPH]) were assessed. All patients also underwent brain MRI at baseline and after one year. Ipsilateral cerebral WMLs were quantified with a semiautomatic method. Results: Mean WML volume significantly increased over a one-year period (6.52 vs. 6.97 mm3, P = 0.005). WML volume at baseline and WML progression did not significantly differ (P>0.05) between patients with 30-49% and patients with 50-69% stenosis. There was a significant correlation between total plaque volume and baseline ipsilateral WML volume (Spearman ¿ = 0.393, P = 0.005). There was no significant correlation between total plaque volume and ipsilateral WML progression. There were no significant associations between LRNC volume and WML volume at baseline and WML progression. WML volume at baseline and WML progression did not significantly differ between patients with a thick and intact FC and patients with a thin and/or ruptured FC. WML volume at baseline and WML progression also did not significantly differ between patients with and without IPH. Conclusion: The results of this study indicate that carotid plaque burden is significantly associated with WML severity, but that there is no causal relationship between carotid plaque vulnerability and the occurrence of WMLs. © 2011 Kwee et al
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