Modelling postharvest quality behaviour as affected by preharvest conditions

Some hundred years ago, wise men decided that preharvest research and applications had to be regarded separated from the postharvest handling and behaviour. Over the years, both areas developed completely separated. Control over both areas was obtained by different companies and advisory boards, with mostly not too good means of communication between them. This decision hampered seriously the consistent and integral development of knowledge on food production and usage. Bridging the gap between all the knowledge and expertise available in the preharvest area of growing food and the postharvest area of storing and processing food, has become and is still becoming more and more important over the last couple of years. In this paper, based on theoretical considerations, on plausible (but unproven) mechanisms and applying the fundamental rules of chemical kinetics, a pathway to deduce general and generic models is developed towards a possible approach to integrate all available knowledge. Still the validity of this approach is not proven. However, a number of examples from both the applied as well as the fundamental point of view are elaborated to indicate such an interaction exists, and to indicate how to tackle the modelling problem. The examples range from physiological disorders like core brown, internal brown, chilling injury and the biological age of individual tomatoes in truss tomatoes as related to the maturity at harves

Vector boson mass generation without new fields

Previously a model of only vector fields with a local U(2) symmetry was introduced for which one finds a massless U(1) photon and a massive SU(2) vector boson in the lattice regularization. Here it is shown that quantization of its classical continuum action leads to perturbative renormalization difficulties. But, non-perturbative Monte Carlo calculations favor the existence of a quantum continuum limit.Comment: 4 pages, 3 figures, 2 tables. Revised after referee reports. One error eliminate

Leading quantum gravitational corrections to QED

We consider the leading post-Newtonian and quantum corrections to the non-relativistic scattering amplitude of charged spin-1/2 fermions in the combined theory of general relativity and QED. The coupled Dirac-Einstein system is treated as an effective field theory. This allows for a consistent quantization of the gravitational field. The appropriate vertex rules are extracted from the action, and the non-analytic contributions to the 1-loop scattering matrix are calculated in the non-relativistic limit. The non-analytical parts of the scattering amplitude are known to give the long range, low energy, leading quantum corrections, are used to construct the leading post-Newtonian and quantum corrections to the two-particle non-relativistic scattering matrix potential for two massive fermions with electric charge.Comment: 14 pages, 29 figures, format RevTex

Vacuum energy: quantum hydrodynamics vs quantum gravity

We compare quantum hydrodynamics and quantum gravity. They share many common features. In particular, both have quadratic divergences, and both lead to the problem of the vacuum energy, which in the quantum gravity transforms to the cosmological constant problem. We show that in quantum liquids the vacuum energy density is not determined by the quantum zero-point energy of the phonon modes. The energy density of the vacuum is much smaller and is determined by the classical macroscopic parameters of the liquid including the radius of the liquid droplet. In the same manner the cosmological constant is not determined by the zero-point energy of quantum fields. It is much smaller and is determined by the classical macroscopic parameters of the Universe dynamics: the Hubble radius, the Newton constant and the energy density of matter. The same may hold for the Higgs mass problem: the quadratically divergent quantum correction to the Higgs potential mass term is also cancelled by the microscopic (trans-Planckian) degrees of freedom due to thermodynamic stability of the whole quantum vacuum.Comment: 14 pages, no figures, added section on the problem of Higgs mass, version accepted for the special issue of JETP Letter

Neutrino Masses from R-Parity Violation with a Z3Z_3 Symmetry

Peer reviewe

Heavy Fermion Screening Effects and Gauge Invariance

We show that the naively expected large virtual heavy fermion effects in low energy processes may be screened if the process under consideration contains external gauge bosons constrained by gauge invariance. We illustrate this by a typical example of the process $\gamma\gamma\to b \bar{b}$. Phenomenological implications are also briefly indicated.Comment: a miss-print fixed, 7 pages, LaTex, no figure

Unitarity and Bounds on the Scale of Fermion Mass Generation

The scale of fermion mass generation can, as shown by Appelquist and Chanowitz, be bounded from above by relating it to the scale of unitarity violation in the helicity nonconserving amplitude for fermion-anti-fermion pairs to scatter into pairs of longitudinally polarized electroweak gauge bosons. In this paper, we examine the process t tbar -> W_L W_L in a family of phenomenologically-viable deconstructed Higgsless models and we show that scale of unitarity violation depends on the mass of the additional vector-like fermion states that occur in these theories (the states that are the deconstructed analogs of Kaluza-Klein partners of the ordinary fermions in a five-dimensional theory). For sufficiently light vector fermions, and for a deconstructed theory with sufficiently many lattice sites (that is, sufficiently close to the continuum limit), the Appelquist-Chanowitz bound can be substantially weakened. More precisely, we find that, as one varies the mass of the vector-like fermion for fixed top-quark and gauge-boson masses, the bound on the scale of top-quark mass generation interpolates smoothly between the Appelquist-Chanowitz bound and one that can, potentially, be much higher. In these theories, therefore, the bound on the scale of fermion mass generation is independent of the bound on the scale of gauge-boson mass generation. While our analysis focuses on deconstructed Higgsless models, any theory in which top-quark mass generation proceeds via the mixing of chiral and vector fermions will give similar results.Comment: 12 pages, 11 eps figures included, revtex. Refrences added; wording modified slightly to emphasize focus on top-quar

Cardiac Autonomic Nervous System in Heart Failure: Imaging Technique and Clinical Implications

The autonomic nervous system interacts in the pathophysiology of heart failure. Dysfunction of the sympathetic nervous system has been identified as an important prognostic marker in patients with chronic heart failure. At present, cardiac sympathetic nerve imaging with 123-iodine metaiodobenzylguanidine [123-I MIBG] has been employed most frequently for the assessment of cardiac sympathetic innervation and activation pattern. The majority of studies have shown that cardiac sympathetic dysfunction as assessed with 123-I MIBG imaging is a powerful predictor for heart failure mortality and morbidity. Additionally, 123-I MIBG imaging can be used for prediction of potentially lethal ventricular tachyarrhythmias in heart failure patients. At present however, the lack of standardization of 123-I MIBG imaging procedures represents an evident issue. Standardized criteria on the use of 123-I MIBG imaging will further strengthen the clinical use of 123-I MIBG imaging in heart failure patients

The Nambu sum rule and the relation between the masses of composite Higgs bosons

We review the known results on the bosonic spectrum in various NJL models both in the condensed matter physics and in relativistic quantum field theory including $^3$He-B, $^3$He-A, the thin films of superfluid He-3, and QCD (Hadronic phase and the Color Flavor Locking phase). Next, we calculate bosonic spectrum in the relativistic model of top quark condensation suggested in \cite{Miransky}. In all considered cases the sum rule appears that relates the masses (energy gaps) $M_{boson}$ of the bosonic excitations in each channel with the mass (energy gap) of the condensed fermion $M_f$ as $\sum M_{boson}^2 = 4 M_f^2$. Previously this relation was established by Nambu in \cite{Nambu} for $^3$He-B and for the s - wave superconductor. We generalize this relation to the wider class of models and call it the Nambu sum rule. We discuss the possibility to apply this sum rule to various models of top quark condensation. In some cases this rule allows to calculate the masses of extra Higgs bosons that are the Nambu partners of the 125 GeV Higgs.Comment: Latex, 15 page

Indirect Collider Signals for Extra Dimensions

A recent suggestion that quantum gravity may become strong near the weak scale has several testable consequences. In addition to probing for the new large (submillimeter) extra dimensions associated with these theories via gravitational experiments, one could search for the Kaluza Klein towers of massive gravitons which are predicted in these models and which can interact with the fields of the Standard Model. Here we examine the indirect effects of these massive gravitons being exchanged in fermion pair production in \epem annihilation and Drell-Yan production at hadron colliders. In the latter case, we examine a novel feature of this theory, which is the contribution of gluon gluon initiated processes to lepton pair production. We find that these processes provide strong bounds, up to several TeV, on the string scale which are essentially independent of the number of extra dimensions. In addition, we analyze the angular distributions for fermion pair production with spin-2 graviton exchanges and demonstrate that they provide a smoking gun signal for low-scale quantum gravity which cannot be mimicked by other new physics scenarios.Comment: Corrected typos, added table and reference