A New Class of Four-Dimensional N=1 Supergravity with Non-minimal Derivative Couplings

In the N=1 four-dimensional new-minimal supergravity framework, we supersymmetrise the coupling of the scalar kinetic term to the Einstein tensor. This coupling, although introduces a non-minimal derivative interaction of curvature to matter, it does not introduce harmful higher-derivatives. For this construction, we employ off-shell chiral and real linear multiplets. Physical scalars are accommodated in the chiral multiplet whereas curvature resides in a linear one.Comment: 18 pages, version published at JHE

Magnetized Tolman-Bondi Collapse

We investigate the gravitational implosion of magnetized matter by studying the inhomogeneous collapse of a weakly magnetized Tolman-Bondi spacetime. The role of the field is analyzed by looking at the convergence of neighboring particle worldlines. In particular, we identify the magnetically related stresses in the Raychaudhuri equation and use the Tolman-Bondi metric to evaluate their impact on the collapsing dust. We find that, despite the low energy level of the field, the Lorentz force dominates the advanced stages of the collapse, leading to a strongly anisotropic contraction. In addition, of all the magnetic stresses, those that resist the collapse are found to grow faster.Comment: 6 pages, RevTex; v2: physical interpretation of the results slightly changed, references added, version accepted in Phys. Rev. D (2006

Endoscopic radiofrequency facet joint treatment in patients with low back pain: technique and long-term results. A prospective cohort study

Aims: The aim of the study was to evaluate the efficacy of endoscopic rhizotomy (ER) for denervation of lumbar facet joints in patients with chronic low back pain (LBP) due to facet joint syndrome (FJS). Methods: A total of 50 consecutive patients suffering from chronic LBP due to facet joints were screened to be treated with ER. The patients participating in the study had a 2-year follow up. Numeric Rating Scale (NRS) and Oswestry Disability Index (ODI) were assessed in the preoperative and postoperative period. To evaluate secondary endpoints, patients were divided into groups. One group included the patients previously treated with percutaneous radiofrequency (RF). The other group comprised patients at their first interventional treatment. We also compared patients dividing them by age and by number of joints treated, trying to elucidate if these parameters could be predictive of effectiveness of the procedure. Results: All patients had a reduction in NRS and an improvement in ODI. NRS was reduced significantly after 1 month and remained the same until the end of the study. ODI was significantly improved from T1 (1 month after surgery) up to T7 (end of the study). The improvements did not differ whether already treated with percutaneous rhizotomy or not. Patients less than 60 years or with 1–2 joints treated had better improvement compared with the others. Conclusion: The results obtained demonstrate that ER for denervation of the facet joint is an effective treatment in patients with chronic LBP, with consistent and stable results at 2-year follow up. The technique has a rapid learning curve and no major complications occurred. Moreover, the previous percutaneous RF treatment had no influence on the results obtained with endoscopic technique. There is evidence that best results are obtained in younger patients and/or in patients with 1–2 joints treated. Lay summary: Low-back pain has facet joints inflammation or degeneration as pain generator in 20–40% of cases. Nervous lesion of the dorsal ramus innervating the facet joints has been shown as an efficacious treatment to obtain good analgesia. Percutaneous techniques have provided short term results for several reasons. This research aimed to see whether endoscopic denervation, which guarantees a more precise approach to anatomical structure, would result in more durable results. The study conducted on 40 patients has made it clear that this approach gives significant analgesia for at least 2 years, which was the time of patient follow up

Endoscopic neuromodulation of suprascapular nerve in chronic shoulder pain: A case report

Shoulder pain is very frequent, especially in middle-aged male adults. Its treatment may be very problematic, mainly in patients who cannot rest and stop their work. At present, it is treated with analgesics, physiotherapy, infiltration of corticosteroids, and/or radiofrequency neuromodulation of the suprascapular nerve. This may be effective but not easy to do. Its efficacy is limited in time, especially because the approach to the nerve trunk may be problematic for its anatomical nature. Ultrasonography has helped, but it is not always completely helpful, due to the small dimension and the complexity of the anatomical structure. In this case report, we describe a more helpful approach to the nerve trunk using an endoscopic technique. The results are very promising. However, larger studies would be necessary to make clear its usefulness. © 2020, Author(s)

Particle Kinematics in Horava-Lifshitz Gravity

We study the deformed kinematics of point particles in the Horava theory of gravity. This is achieved by considering particles as the optical limit of fields with a generalized Klein-Gordon action. We derive the deformed geodesic equation and study in detail the cases of flat and spherically symmetric (Schwarzschild-like) spacetimes. As the theory is not invariant under local Lorenz transformations, deviations from standard kinematics become evident even for flat manifolds, supporting superluminal as well as massive luminal particles. These deviations from standard behavior could be used for experimental tests of this modified theory of gravity.Comment: Added references, corrected a typing erro

Stable Exact Solutions in Cosmological Models with Two Scalar Fields

The stability of isotropic cosmological solutions for two-field models in the Bianchi I metric is considered. We prove that the sufficient conditions for the Lyapunov stability in the Friedmann-Robertson-Walker metric provide the stability with respect to anisotropic perturbations in the Bianchi I metric and with respect to the cold dark matter energy density fluctuations. Sufficient conditions for the Lyapunov stability of the isotropic fixed points of the system of the Einstein equations have been found. We use the superpotential method to construct stable kink-type solutions and obtain sufficient conditions on the superpotential for the Lyapunov stability of the corresponding exact solutions. We analyze the stability of isotropic kink-type solutions for string field theory inspired cosmological models.Comment: 23 pages, v3:typos corrected, references adde

Fertilizer Potential of Organic-Based Soil Amendments on cv. Sangiovese (V. vinifera L.) Vines: Preliminary Results

The intensification of highly specialized viticulture has led to a dramatic decrease of soil fertility that can be restored by increasing soil organic matter using organic fertilizers. The aim of the present experiment was to evaluate the effect of different organic amendments on vine vegetative growth and nutritional status, soil N availability and microbial biomass, as well as on yield and grape quality. The experiment was carried out in 2020 and 2021, on cv. Sangiovese (Vitis vinifera L.) vines grafted on 110 Richter (V. berlandieri × V. rupestris) planted in February 2019. Plants were fer-tilized yearly in spring with (1) mineral fertilization (MIN), (2) municipal organic waste compost (MOW), and (3) sewage sludge compost (SS). The application of SS increased nitrate availability in both years, while the supply of organic matter (no matter the source) enhanced soil microbial bio-mass content. Plant nutritional status was in the optimal range for all treatments, with an increase of N in SS and K in MOW. Fruit yield in 2020 was not influenced by treatments, while in 2021 it was enhanced by MIN and MOW, which also induced a higher berry quality. Plant vegetative growth was stimulated by the application of SS. In conclusion, from these preliminary results we observed a higher N availability as a consequence of SS supply that resulted in a higher plant biomass, but reduced yield and berry quality, supporting the theory that for vineyards, N should be carefully managed to reach an equilibrium between vegetative and reproductive activity

General Gauss-Bonnet brane cosmology

We consider 5-dimensional spacetimes of constant 3-dimensional spatial curvature in the presence of a bulk cosmological constant. We find the general solution of such a configuration in the presence of a Gauss-Bonnet term. Two classes of non-trivial bulk solutions are found. The first class is valid only under a fine tuning relation between the Gauss-Bonnet coupling constant and the cosmological constant of the bulk spacetime. The second class of solutions are static and are the extensions of the AdS-Schwarzchild black holes. Hence in the absence of a cosmological constant or if the fine tuning relation is not true, the generalised Birkhoff's staticity theorem holds even in the presence of Gauss-Bonnet curvature terms. We examine the consequences in brane world cosmology obtaining the generalised Friedmann equations for a perfect fluid 3-brane and discuss how this modifies the usual scenario.Comment: 20 pages, no figures, typos corrected, refs added, section IV changed yielding novel result

Conditions for the cosmological viability of the most general scalar-tensor theories and their applications to extended Galileon dark energy models

In the Horndeski's most general scalar-tensor theories with second-order field equations, we derive the conditions for the avoidance of ghosts and Laplacian instabilities associated with scalar, tensor, and vector perturbations in the presence of two perfect fluids on the flat Friedmann-Lemaitre-Robertson-Walker (FLRW) background. Our general results are useful for the construction of theoretically consistent models of dark energy. We apply our formulas to extended Galileon models in which a tracker solution with an equation of state smaller than -1 is present. We clarify the allowed parameter space in which the ghosts and Laplacian instabilities are absent and we numerically confirm that such models are indeed cosmologically viable.Comment: 18 pages, 6 figure