862 research outputs found

    Diabatic description of charmoniumlike mesons II: mass corrections and strong decay widths

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    From a diabatic bound state approach to JPC=1−−J^{PC}=1^{--} and (0,1,2)++(0,1,2)^{++} charmoniumlike resonances below 4.14.1 GeV, formulated in terms of cc‾{c\overline{c}} and closed meson-meson channels, we calculate mass shifts and widths due to open meson-meson channels. This calculation does not involve any new free parameter, so comparison of our predictions with existing data provides a direct test of our approach. Further mass corrections are also estimated and good agreement with the measured masses comes out. As for the calculated widths, overall reasonable, they point out to the need of some refinement of our current bound state approximation for an accurate description of data. These results give additional support to the diabatic approach in QCD as an adequate framework for a complete unified description of conventional and unconventional charmoniumlike resonances. In this respect, the experimental discovery of a predicted 2++2^{++} resonance with a mass around 44 GeV would be of special relevance.Comment: 9 pages, 5 tables; v2: new appendix, extended Introduction and Results, additional references, other small additions and correction

    χc1(2p)\chi_{c1}(2p): an overshadowed charmoniumlike resonance

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    A thorough study of the JPC=1++J^{PC}=1^{++} elastic D0Dˉ∗0D^{0}\bar{D}^{\ast0} and D+D∗−D^{+}D^{\ast-} scattering, where the form of the meson-meson interaction is inferred from lattice QCD calculations of string breaking, is carried out for center-of-mass energies up to 4~GeV. We show that the presence of χc1(3872)\chi_{c1}(3872), which can be naturally assigned to either a bound or virtual charmoniumlike state close below the D0Dˉ∗0D^{0}\bar{D}^{\ast0} threshold, can overshadow a quasiconventional charmoniumlike resonance lying above threshold. This makes difficult the experimental detection of this resonance through the D0Dˉ∗0D^{0}\bar{D}^{\ast0} and D+D∗−D^{+}D^{\ast-} channels, despite being its expected main decay modes. We analyze alternative strong and electromagnetic decay modes. Comparison with existing data shows that this resonance may have already been observed through its decay to ωJ/ψ\omega J/\psi.Comment: 10 pages, 11 figures; v2: updated figures, expanded text, new references, updated acknowledgements, additional minor change

    The decline of the charismatic Parnassius mnemosyne (L.) (Lepidoptera: Papilionidae) in a central italy national park: A call for urgent actions

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    Here we report the strong decline of a population of the endangered species Parnassius mnemosyne (Linnaeus, 1758) (Lepidoptera: Papilionidae) in the National Park of Foreste Casentinesi, Monte Falterona and Campigna (Italy). We compared historical presence data (before 1969) with current data from two years of monitoring (2018–2019) and provided evidence of a drastic reduction in the number of sites inhabited by the species. A preliminary assessment suggested that the population of P. mmemosyne occurring in the Park is limited to a few individuals. We argue that the population of this iconic and charismatic butterfly is at the verge of extinction in this National Park, probably because of a combination of habitat loss (i.e. decrease in size and number of areas of open grassland on the mountain belt) and climatic changes. Being one of the few populations of P. mnemosyne in the Northern Apennines, the implementation of protection measures is a high conservation priority. Several other butterfly species on the Italian mountains that are facing the same survival challenges would also benefit from the establishment of conservation actions aimed at improving habitat quality for P. mnemosyne. Present article is meant to call for action researchers, stakeholders, and especially decision-makers in order to increase the efforts to upturn the evident decline in abundance of this population

    Bone-Anchored Hearing Aids Fitted According to NAL and DSL Procedures in Adults with Mixed Hearing Loss

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    BACKGROUND: Bone-anchored hearing aids represent a valid alternative for patients with conductive/mixed hearing loss who cannot use hearing aids. To date, these devices have given good audiological results, thanks to various fitting prescription programs (i.e., National Acoustic Laboratories and Desired Sensation Level). The aim of this study is to compare 2 types of fitting algorithms (National Acoustic Laboratories and Desired Sensation Level) implemented for bone-anchored hearing devices. METHODS: We retrospectively enrolled 10 patients followed at our operative unit, suffering from bilateral symmetrical mixed hearing loss and who underwent bone-anchored hearing aid implantation. All patients experienced each prescriptive procedure, National Acoustic Laboratories and Desired Sensation Level, for 7 months (on average), and they were subjected to audiological tests and questionnaires to evaluate the best program. RESULTS: National Acoustic Laboratories and Desired Sensation Level prescriptions yielded similar results. Desired Sensation Level allowed less amplification of the low frequencies than the National Acoustic Laboratories prescription, and these differences were the only statistically significant. Desired Sensation Level allowed better disyllabic word and sentence recognition scores only in quiet and not in noisy conditions. The subjective questionnaires showed similar results. At the end of the trial sessions, more patients (60%) definitively chose the Desired Sensation Level program for their device. These patients were those with a worse hearing threshold. CONCLUSION: The 2 prescriptive programs allowed similar results although patients with a worse threshold seem to prefer the DSL program. This is the first evaluation of the 2 prescriptive programs, National Acoustic Laboratories versus Desired Sensation Level, for bone conduction devices available in the literature. Further studies are needed to confirm this initial finding

    Another look at the BL Lacertae flux and spectral variability

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    The GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT) monitored BL Lacertae in 2008-2009 at radio, near-IR, and optical frequencies. During this period, high-energy observations were performed by XMM-Newton, Swift, and Fermi. We analyse these data with particular attention to the calibration of Swift UV data, and apply a helical jet model to interpret the source broad-band variability. The GASP-WEBT observations show an optical flare in 2008 February-March, and oscillations of several tenths of mag on a few-day time scale afterwards. The radio flux is only mildly variable. The UV data from both XMM-Newton and Swift seem to confirm a UV excess that is likely caused by thermal emission from the accretion disc. The X-ray data from XMM-Newton indicate a strongly concave spectrum, as well as moderate flux variability on an hour time scale. The Swift X-ray data reveal fast (interday) flux changes, not correlated with those observed at lower energies. We compare the spectral energy distribution (SED) corresponding to the 2008 low-brightness state, which was characterised by a synchrotron dominance, to the 1997 outburst state, where the inverse-Compton emission was prevailing. A fit with an inhomogeneous helical jet model suggests that two synchrotron components are at work with their self inverse-Compton emission. Most likely, they represent the radiation from two distinct emitting regions in the jet. We show that the difference between the source SEDs in 2008 and 1997 can be explained in terms of pure geometrical variations. The outburst state occurred when the jet-emitting regions were better aligned with the line of sight, producing an increase of the Doppler beaming factor. Our analysis demonstrates that the jet geometry can play an extremely important role in the BL Lacertae flux and spectral variability.Comment: 12 pages, 10 figures, accepted for publication in A&

    The path from trigeminal asymmetry to cognitive impairment: a behavioral and molecular study

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    Trigeminal input exerts acute and chronic effects on the brain, modulating cognitive functions. Here, new data from humans and animals suggest that these effects are caused by trigeminal influences on the Locus Coeruleus (LC). In humans subjects clenching with masseter asymmetric activity, occlusal correction improved cognition, alongside with reductions in pupil size and anisocoria, proxies of LC activity and asymmetry, respectively. Notably, reductions in pupil size at rest on the hypertonic side predicted cognitive improvements. In adult rats, a distal unilateral section of the trigeminal mandibular branch reduced, on the contralateral side, the expression of c-Fos (brainstem) and BDNF (brainstem, hippocampus, frontal cortex). This counterintuitive finding can be explained by the following model: teeth contact perception loss on the lesioned side results in an increased occlusal effort, which enhances afferent inputs from muscle spindles and posterior periodontal receptors, spared by the distal lesion. Such effort leads to a reduced engagement of the intact side, with a corresponding reduction in the afferent inputs to the LC and in c-Fos and BDNF gene expression. In conclusion, acute effects of malocclusion on performance seem mediated by the LC, which could also contribute to the chronic trophic dysfunction induced by loss of trigeminal input
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