Studies on the antioxidative activity of red pigments in Italian-type dry-cured ham

Aqueous phosphate buffer extracts and acetone/water extracts of pigments from Parma ham were assessed as antioxidants by (1) electron spin resonance spectroscopy using a spin probing technique to evaluate their efficiencies as scavengers of free radicals, and (2) by electrochemical measurement of oxygen depletion rate in an aqueous methyl linoleate emulsion to evaluate their efficiencies as chain-breaking antioxidant, and using both methods, compared with the effect of apomyoglobin and nitrosylmyoglobin. Aqueous phosphate extracts and acetone/water extracts of Parma ham pigment both scavenged a semi-stable nitroxide radical (Fremy's salt), and both extracts reduced the rate of oxygen consumption for lipid peroxidation (initiated by metmyoglobin) very efficiently. For apomyoglobin no antioxidative capacity was observed, and the heme moiety of the pigment(s) of Parma ham were concluded to have antioxidative properties. The more lipophilic pigment, as extracted by acetone/water, had the most significant effect, and its ability to inhibit lipid oxidation was further tested in a model food system based on cooked pork. The lipid oxidation was increasingly inhibited by increasing additions from 0.12 ppm to 0.24 ppm Parma ham pigment, and the pigment protected a-tocopherol against degradation in a concentration dependent manner

Asymptotic statistics of the n-sided planar Voronoi cell: II. Heuristics

We develop a set of heuristic arguments to explain several results on planar Poisson-Voronoi tessellations that were derived earlier at the cost of considerable mathematical effort. The results concern Voronoi cells having a large number n of sides. The arguments start from an entropy balance applied to the arrangement of n neighbors around a central cell. It is followed by a simplified evaluation of the phase space integral for the probability p_n that an arbitrary cell be n-sided. The limitations of the arguments are indicated. As a new application we calculate the expected number of Gabriel (or full) neighbors of an n-sided cell in the large-n limit.Comment: 22 pages, 10 figure

Completeness of case ascertainment and survival time error in English cancer registries: impact on 1-year survival estimates.

BACKGROUND: It has been suggested that cancer registries in England are too dependent on processing of information from death certificates, and consequently that cancer survival statistics reported for England are systematically biased and too low. METHODS: We have linked routine cancer registration records for colorectal, lung, and breast cancer patients with information from the Hospital Episode Statistics (HES) database for the period 2001-2007. Based on record linkage with the HES database, records missing in the cancer register were identified, and dates of diagnosis were revised. The effects of those revisions on the estimated survival time and proportion of patients surviving for 1 year or more were studied. Cases that were absent in the cancer register and present in the HES data with a relevant diagnosis code and a relevant surgery code were used to estimate (a) the completeness of the cancer register. Differences in survival times calculated from the two data sources were used to estimate (b) the possible extent of error in the recorded survival time in the cancer register. Finally, we combined (a) and (b) to estimate (c) the resulting differences in 1-year cumulative survival estimates. RESULTS: Completeness of case ascertainment in English cancer registries is high, around 98-99%. Using HES data added 1.9%, 0.4% and 2.0% to the number of colorectal, lung, and breast cancer registrations, respectively. Around 5-6% of rapidly fatal cancer registrations had survival time extended by more than a month, and almost 3% of rapidly fatal breast cancer records were extended by more than a year. The resulting impact on estimates of 1-year survival was small, amounting to 1.0, 0.8, and 0.4 percentage points for colorectal, lung, and breast cancer, respectively. INTERPRETATION: English cancer registration data cannot be dismissed as unfit for the purpose of cancer survival analysis. However, investigators should retain a critical attitude to data quality and sources of error in international cancer survival studies

New Path Equations in Absolute Parallelism Geometry

The Bazanski approach, for deriving the geodesic equations in Riemannian geometry, is generalized in the absolute parallelism geometry. As a consequence of this generalization three path equations are obtained. A striking feature in the derived equations is the appearance of a torsion term with a numerical coefficients that jumps by a step of one half from equation to another. This is tempting to speculate that the paths in absolute parallelism geometry might admit a quantum feature.Comment: 4 pages Latex file Journal Reference: Astrophysics and space science 228, 273, (1995

Schwarzschild Tests of the Wahlquist-Estabrook-Buchman-Bardeen Tetrad Formulation for Numerical Relativity

A first order symmetric hyperbolic tetrad formulation of the Einstein equations developed by Estabrook and Wahlquist and put into a form suitable for numerical relativity by Buchman and Bardeen (the WEBB formulation) is adapted to explicit spherical symmetry and tested for accuracy and stability in the evolution of spherically symmetric black holes (the Schwarzschild geometry). The lapse and shift which specify the evolution of the coordinates relative to the tetrad congruence are reset at frequent time intervals to keep the constant-time hypersurfaces nearly orthogonal to the tetrad congruence and the spatial coordinate satisfying a kind of minimal rate of strain condition. By arranging through initial conditions that the constant-time hypersurfaces are asymptotically hyperbolic, we simplify the boundary value problem and improve stability of the evolution. Results are obtained for both tetrad gauges (``Nester'' and ``Lorentz'') of the WEBB formalism using finite difference numerical methods. We are able to obtain stable unconstrained evolution with the Nester gauge for certain initial conditions, but not with the Lorentz gauge.Comment: (accepted by Phys. Rev. D) minor changes; typos correcte

An analytical treatment of the Clock Paradox in the framework of the Special and General Theories of Relativity

In this paper we treat the so called clock paradox in an analytical way by assuming that a constant and uniform force F of finite magnitude acts continuously on the moving clock along the direction of its motion assumed to be rectilinear. No inertial motion steps are considered. The rest clock is denoted as (1), the to-and-fro moving clock is (2), the inertial frame in which (1) is at rest in its origin and (2) is seen moving is I and, finally, the accelerated frame in which (2) is at rest in its origin and (1) moves forward and backward is A. We deal with the following questions: I) What is the effect of the finite force acting on (2) on the proper time intervals measured by the two clocks when they reunite? Does a differential aging between the two clocks occur, as it happens when inertial motion and infinite values of the accelerating force is considered? The Special Theory of Relativity is used in order to describe the hyperbolic motion of (2) in the frame I II) Is this effect an absolute one, i.e. does the accelerated observer A comoving with (2) obtain the same results as that in I, both qualitatively and quantitatively, as it is expected? We use the General Theory of Relativity in order to answer this question.Comment: LaTex2e, 19 pages, no tables, no figures. Rewritten version, it amends the previous one whose results about the treatment with General Relativity were wrong. References added. Eq. (55) corrected. More refined version. Comments and suggestions are warmly welcom

Huygens' Principle for the Klein-Gordon equation in the de Sitter spacetime

In this article we prove that the Klein-Gordon equation in the de Sitter spacetime obeys the Huygens' principle only if the physical mass $m$ of the scalar field and the dimension $n\geq 2$ of the spatial variable are tied by the equation $m^2=(n^2-1)/4$. Moreover, we define the incomplete Huygens' principle, which is the Huygens' principle restricted to the vanishing second initial datum, and then reveal that the massless scalar field in the de Sitter spacetime obeys the incomplete Huygens' principle and does not obey the Huygens' principle, for the dimensions $n=1,3$, only. Thus, in the de Sitter spacetime the existence of two different scalar fields (in fact, with m=0 and $m^2=(n^2-1)/4$), which obey incomplete Huygens' principle, is equivalent to the condition $n=3$ (in fact, the spatial dimension of the physical world). For $n=3$ these two values of the mass are the endpoints of the so-called in quantum field theory the Higuchi bound. The value $m^2=(n^2-1)/4$ of the physical mass allows us also to obtain complete asymptotic expansion of the solution for the large time. Keywords: Huygens' Principle; Klein-Gordon Equation; de Sitter spacetime; Higuchi Boun

Spacetime dynamics of spinning particles - exact electromagnetic analogies

We compare the rigorous equations describing the motion of spinning test particles in gravitational and electromagnetic fields, and show that if the Mathisson-Pirani spin condition holds then exact gravito-electromagnetic analogies emerge. These analogies provide a familiar formalism to treat gravitational problems, as well as a means for comparing the two interactions. Fundamental differences are manifest in the symmetries and time projections of the electromagnetic and gravitational tidal tensors. The physical consequences of the symmetries of the tidal tensors are explored comparing the following analogous setups: magnetic dipoles in the field of non-spinning/spinning charges, and gyroscopes in the Schwarzschild, Kerr, and Kerr-de Sitter spacetimes. The implications of the time projections of the tidal tensors are illustrated by the work done on the particle in various frames; in particular, a reciprocity is found to exist: in a frame comoving with the particle, the electromagnetic (but not the gravitational) field does work on it, causing a variation of its proper mass; conversely, for "static observers," a stationary gravitomagnetic (but not a magnetic) field does work on the particle, and the associated potential energy is seen to embody the Hawking-Wald spin-spin interaction energy. The issue of hidden momentum, and its counterintuitive dynamical implications, is also analyzed. Finally, a number of issues regarding the electromagnetic interaction and the physical meaning of Dixon's equations are clarified.Comment: 32+11 pages, 5 figures. Edited and further improved version, with new Section C.2 unveiling analogies for arbitrary spin conditions, and new Sec. 3.2.3 in the Supplement making connection to the post-Newtonian approximation; former Sec. III.B.4 and Appendix C moved to the (reshuffled) Supplement; references updated. The Supplement is provided in ancillary file. Matches the final published versio