In this paper, we propose to use 4D graph cuts for the segmentation of large spatio-temporal (4D) datasets. Indeed, as 4D datasets grow in popularity in many clinical areas, so will the demand for efficient general segmentation algorithms. The graph cuts method has become a leading method for complex 2D and 3D image segmentation in many applications. Despite a few attempts in 4D, the use of gra...

Four-dimensional, cone-beam CT (4D CBCT) substantially reduces respiration-induced motion blurring artifacts in three-dimension (3D) CBCT. However, the image quality of 4D CBCT is significantly degraded which may affect its accuracy in localizing a mobile tumor for high-precision, image-guided radiation therapy (IGRT). The purpose of this study was to investigate the impact of scanning paramete...

1. To develop a state-of-the-art ocean 4-dimensional variational (4D-Var) data assimilation and ocean forecasting system for the Regional Ocean Modeling System (ROMS); 2. To develop a state-of-the-art suite of post-processing and diagnostic tools in support of ROMS 4D-Var; 3. To gain the necessary experience using the ROMS 4D-Var systems in complex circulation environments; 4. To train the next...

Four-dimensional (4D) simplicial quantum gravity coupled to both scalar fields (NX) and gauge fields (NA) has been studied using Monte-Carlo simulations. The matter dependence of the string susceptibility exponent γ (4) is estimated. Furthermore, we compare our numerical results with Background-Metric-Independent (BMI) formulation conjectured to describe the quantum field theory of gravity in 4...

Finger-length ratio (second to fourth finger; 2D:4D) has been associated with various measures thought to be related to prenatal androgens. In addition, hormone-transfer theory posits that hormones can transfer between twins. We examined 2D:4D in same-sex (SS) and opposite-sex (OS) dizygotic twins to test both propositions. Results show that 2D:4D is masculinized in OS females compared to SS fe...

BACKGROUND Identification of prenatal ventriculoarterial connections in fetuses with conotruncal anomalies (CTA) remains one of the greatest challenges for sonographers performing screening examinations. Herein, we propose a novel protocol of 4D volume analysis that identifies ventriculoarterial connections and evaluate its clinical utility in routine screenings. METHODS Twenty-nine cases of ...

Background 4D phase contrast magnetic resonance blood flow measurements (4D PC-MR) is a promising tool for clinical assessment of cardiac function, but lack of independent validation may limit clinical adoption. Previous validation studies are limited by lack of pulsatility [1,2] or by the need of a post hoc correction factor to compensate for differences in experimental setup between 4D PC-MR ...

Using the Hamilton-Jacobi formalism, we study extra force and extra mass in a recently introduced noncompact Kaluza-Klein cosmological model. We examine the inertial 4D mass m 0 of the inflaton field on a 4D FRW bulk in two examples. We find that m 0 has a geometrical origin and antigravitational effects on a non inertial 4D bulk should be a consequence of the motion of the fifth coordinate wit...

We discuss the dynamics of a particular two-dimensional (2D) physical system in the four dimensional (4D) (non-)commutative phase space by exploiting the consistent Hamiltonian and Lagrangian formalisms based on the symplectic structures defined on the 4D (non-)commutative cotangent manifolds. The noncommutativity exists equivalently in the coordinate or the momentum planes embedded in the 4D c...