23,720 research outputs found

    Toroidal, compression, and vortical dipole strengths in 144154^{144-154}Sm: Skyrme-RPA exploration of deformation effect

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    A comparative analysis of toroidal, compressional and vortical dipole strengths in the spherical 144^{144}Sm and the deformed 154^{154}Sm is performed within the random-phase-approximation using a set of different Skyrme forces. Isoscalar (T=0), isovector (T=1), and electromagnetic excitation channels are considered. The role of the nuclear convection jconj_{\text{con}} and magnetization jmagj_{\text{mag}} currents is inspected. It is shown that the deformation leads to an appreciable redistribution of the strengths and causes a spectacular deformation splitting (exceeding 5 MeV) of the isoscalar compressional mode. In 154^{154}Sm, the μ\mu=0 and μ\mu=1 branches of the mode form well separated resonances. When stepping from 144^{144}Sm to 154^{154}Sm, we observe an increase of the toroidal, compression and vortical contributions in the low-energy region (often called pygmy resonance). The strength in this region seems to be an overlap of various excitation modes. The energy centroids of the strengths depend significantly on the isoscalar effective mass m0m_0. Skyrme forces with a large m0m_0 (typically m0/m0.81m_0/m \approx 0.8 - 1) seem to be more suitable for description of experimental data for the isoscalar giant dipole resonance.Comment: 13 pages, 10 figures, submitted to EJP

    Relevance of lactate level detection in migrane and fibromyalgia

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    The aim of this study was to determine the blood lactate levels in healthy and pathological subjects, particularly with migraine and fibromyalgia. Moreover we investigated the possible correlation between lactate concentration, postural stability and balance disorders; the composition of the groups were: migraine (n = 25; age 49.7 +/- 12.5), fibromyalgia (n = 10; age 43.7 +/- 21.2), control group (n = 16 age 28.52 +/- 2.4). The results showed that patients with fibromyalgia (FG) had higher lactate levels compared to migraine (MG) and control group (CG) (mean +/- sd: FG = 1.78 +/- 0.9 mmol/L; MG = 1.45 +/- 1 mmol/L; CG = 0,85 +/- 0,07 mmol/L). The same situation was highlighted about the sway path length with eyes closed (FG = 518 +/- 195 mm; MG = 465 +/- 165 mm; CG = 405 +/- 94,72 mm) and with eyes open (FG = 430 +/- 220 mm; MG = 411 +/- 143 mm; CG = 389 +/- 107 mm). This can be explained by the fact that energy-intensive postural strategies must be used to optimize both static and dynamic coordination, in particular with repeated contractions of tonic oxidative muscle cells responsible for postural control

    Enzymatic activity of anthropogenic proto-organic soils in soilless farming

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    In soilless agriculture and horticulture coir is the more used substratum to grow plants because it is widely available and more environmentally friendly than sphagnum or peat. In Italy, soilless agriculture concerns an area of about 1,000 hectares, particularly concentrated in Sicily. The southern coastal belt of this region is the area interested by the most significant experiences in the application of techniques of soilless cultivation that, recently, has been used also for growing table grapes. Starting from the above consideration we suppose that the features of the coconut fiber underlay an evident transformation and that even after few years of table grape cultivation, such organic material undergone to a transformation that allows for the formation of a proto-organic soil (a proto-Histosol, we supposed). If this is true, we believe that, in this case, to speak about soilless cultivation is for sure misleading for the common people, as we should define this cultivation \u201con anthropogenic soils\u201d instead. To fit the aims of this survey we used a big greenhouse devoted to soilless cultivation of table grape in a farm in the Southern SicilyWe have considered the enzymatic activity that characterized the coconut fiber after 3 cycles of cultivation of table grapes. We used as a control the coconut fiber that the farmer used to prepare pots for soilless cultivation and coconut fiber of: 6 pots at the end of the first productive cycle 6 pots at the end of the second cycle and 3 pots at the end of the third cycle. On these organic samples we investigated three enzymes, belonging to oxydoreductase (catalase and dehydrogenase) and hydrolase (urease) classes. Statistical analysis of the investigated enzymes was developed using IBM Statistic SPSS v20 by ANOVA, Tukey test HSD for p 0.01 and Multivariate Statistical Analysis. Results have shown significant differences in enzymes content and quality among coir tests. The use of the coco fiber, as nutritive substratum under fertigation, has positively influenced the growing and proliferation of soil microbes and thus enzymatic activity. In merely 3 productive cycles the stage of decomposition of the organic residues changed highlighting a substantial evolution of such organic material

    Effects of partial rootzone drying and rootstock vigour on growth and fruit quality of 'Pink Lady' apple trees in Mediterranean environments

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    We investigated the effects of partial rootzone drying (PRD) and rootstock vigor on water relations, vegetative and productive performance of \u2018Pink Lady\u2019 apple (Malus domestica Borkh.) trees in central Sicily. In a first field trial, trees on MM.106 rootstock were subjected to: Conventional irrigation (CI), maintaining soil moisture above 80% of field capacity; PRD irrigation, where only one alternated side of the rootzone received 50% of the CI irrigation water; and continuous deficit irrigation (DI), where 50% of the CI water was equally applied to both sides of the rootzone. In a second trial, trees on M.9 or MM.106 were subjected to CI and PRD irrigation. PRD reduced stomatal conductance (gs) more consistently in trees on MM.106 than in trees on M.9, but maintained relative water content (RWC) to the levels of CI. DI induced greater gs reductions than PRD and lower RWC than CI and PRD. Rootstock vigor did not influence plant response to irrigation strategy. PRD induced some reduction in fruit number but no change in yields and fruit quality compared to CI, whereas DI reduced fruit size and marketable yields. Significant reductions in shoot and leaf growth were induced by DI, whereas only leaf growth was affected by PRD. Our observations indicate that responses induced by PRD are due to a combination of the amount and way of applying water, and not just to reductions in irrigation volumes, suggesting a possible use of PRD for increasing apple water use efficiency in Mediterranean environments

    Vacancy decay in endohedral atoms: the role of non-central position of the atom

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    We demonstrate that the Auger decay rate in an endohedral atom is very sensitive to the atom's location in the fullerene cage. Two additional decay channels appear in an endohedral system: (a) the channel due to the change in the electric field at the atom caused by dynamic polarization of the fullerene electron shell by the Coulomb field of the vacancy, (b) the channel within which the released energy is transferred to the fullerene electron via the Coulomb interaction. % The relative magnitudes of the correction terms are dependent not only on the position of the doped atom but also on the transition energy \om. Additional enhancement of the decay rate appears for transitions whose energies are in the vicinity of the fullerene surface plasmons energies of high multipolarity. % It is demonstrated that in many cases the additional channels can dominate over the direct Auger decay resulting in pronounced broadening of the atomic emission lines. % The case study, carried out for Sc2+^{2+}@C806_{80}^{6-}, shows that narrow autoionizing resonances in an isolated Sc2+^{2+} within the range \om = 30... 45 eV are dramatically broadened if the ion is located strongly off-the-center. % Using the developed model we carry out quantitative analysis of the photoionization spectrum for the endohedral complex Sc3_3N@C80_{80} and demonstrate that the additional channels are partly responsible for the strong modification of the photoionization spectrum profile detected experimentally by M\"{u}ller et al. (J. Phys.: Conf. Ser. 88, 012038 (2008)).Comment: 32 pages, 11 figure

    Infrared electron modes in light deformed clusters

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    Infrared quadrupole modes (IRQM) of the valence electrons in light deformed sodium clusters are studied by means of the time-dependent local-density approximation (TDLDA). IRQM are classified by angular momentum components λμ=\lambda\mu =20, 21 and 22 whose μ\mu branches are separated by cluster deformation. In light clusters with a low spectral density, IRQM are unambiguously related to specific electron-hole excitations, thus giving access to the single-electron spectrum near the Fermi surface (HOMO-LUMO region). Most of IRQM are determined by cluster deformation and so can serve as a sensitive probe of the deformation effects in the mean field. The IRQM branch λμ=\lambda\mu =21 is coupled with the magnetic scissors mode, which gives a chance to detect the latter. We discuss two-photon processes, Raman scattering (RS), stimulated emission pumping (SEP), and stimulated adiabatic Raman passage (STIRAP), as the relevant tools to observe IRQM. A new method to detect the IRQM population in clusters is proposed.Comment: 22 pages, 6 figure

    Current strategies for tracheal replacement: A review

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    Airway cancers have been increasing in recent years. Tracheal resection is commonly performed during surgery and is burdened from post-operative complications severely affecting quality of life. Tracheal resection is usually carried out in primary tracheal tumors or other neoplasms of the neck region. Regenerative medicine for tracheal replacement using bio-prosthesis is under current research. In recent years, attempts were made to replace and transplant human cadaver trachea. An effective vascular supply is fundamental for a successful tracheal transplantation. The use of biological scaffolds derived from decellularized tissues has the advantage of a three-dimensional structure based on the native extracellular matrix promoting the perfusion, vascularization, and differentiation of the seeded cell typologies. By appropriately modulating some experimental parameters, it is possible to change the characteristics of the surface. The obtained membranes could theoretically be affixed to a decellularized tissue, but, in practice, it needs to ensure adhesion to the biological substrate and/or glue adhesion with biocompatible glues. It is also known that many of the biocompatible glues can be toxic or poorly tolerated and induce inflammatory phenomena or rejection. In tissue and organ transplants, decellularized tissues must not produce adverse immunological reactions and lead to rejection phenomena; at the same time, the transplant tissue must retain the mechanical properties of the original tissue. This review describes the attempts so far developed and the current lines of research in the field of tracheal replacement

    Evidence of vacuum birefringence from the polarisation of the optical emission from an Isolated Neutron Star

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    Isolated Neutron Stars are some of the most exciting stellar objects known to astronomers: they have the most extreme magnetic fields, with values up to 101510^{15} G, and, with the exception of stellar-mass black holes, they are the most dense stars, with densities of 1014\approx 10^{14} g cm3^{-3}. As such, they are perfect laboratories to test theories of electromagnetism and nuclear physics under conditions of magnetic field and density unattainable on Earth. In particular, the interaction of radiation with strong magnetic fields is the cause of the {\em vacuum birefringence}, an effect predicted by quantum electrodynamics in 1936 but that lacked an observational evidence until now. Here, we show how the study of the polarisation of the optical radiation from the surface of an isolated neutron star yielded such an observational evidence, opening exciting perspectives for similar studies at other wavelengths.Comment: 5 pages, 1 figure, Contributed to the 13th Patras Workshop on Axions, WIMPs and WISPs, Thessaloniki, May 15 to 19, 201
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