632 research outputs found

    Geometrization of Quantum Mechanics

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    We show that it is possible to represent various descriptions of Quantum Mechanics in geometrical terms. In particular we start with the space of observables and use the momentum map associated with the unitary group to provide an unified geometrical description for the different pictures of Quantum Mechanics. This construction provides an alternative to the usual GNS construction for pure states.Comment: 16 pages. To appear in Theor. Math. Phys. Some typos corrected. Definition 2 in page 5 rewritte

    Slightly Non-Minimal Dark Matter in PAMELA and ATIC

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    We present a simple model in which dark matter couples to the standard model through a light scalar intermediary that is itself unstable. We find this model has several notable features, and allows a natural explanation for a surplus of positrons, but no surplus of anti-protons, as has been suggested by early data from PAMELA and ATIC. Moreover, this model yields a very small nucleon coupling, well below the direct detection limits. In this paper we explore the effect of this model in both the early universe and in the galaxy.Comment: 7 pages, 6 figures, v3: updated for new data, added discussion of Ferm

    Evaluation of carcass quality, body and pulmonary lesions detected at the abattoir in heavy pigs subjected or not to tail docking

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    BackgroundNowadays, body and tail lesions and respiratory disease are some of the greatest problems affecting the health and welfare of pigs. The aim of the study was to measure the prevalence of pleurisy, bronchopneumonia (enzootic pneumonia like lesions) and lesions on tail and body of heavy pigs subjected or not to tail docking through the inspection in Italian abattoirs. Additionally, the effect of tail docking and season was investigated on carcass quality (weight, % of lean meat, and Protected Designation of Origin (PDO) classification). For this purpose, a total 17.256 carcasses belonging to 171 batches from 103 farms were inspected in an Italian abattoir between 2019 and 2022. Enzootic pneumonia (EP) like lesions were scored according to the Madec and Derrien method, while pleurisy was scored using the Italian Slaughterhouse pleuritic evaluation system (SPES). For the tail and body, the lesions were scored according to Welfare Quality. The lesion score index (LSI) was calculated for each area. Data were analysed using a general linear model (GLM) including tail caudectomy, season and distance of the farm from the abattoir.ResultsThe warm season increased the percentage of lesions in carcasses in all parts of the body observed (P < 0.0001). The presence of undocked tail increased the LSI of the tail (P < 0.0001). The percentage of limbs lesions with score 2 and limbs LSI increase with increasing duration of transport (coef. = 0.003, P < 0.001; coef. = 0.008, P < 0.001; respectively). The hot carcass weight and the percentage of carcasses included in the PDO were higher in batches with docked tails (P = 0.027; P < 0.001, respectively), while the percentage of lean meat was higher in batches with undocked tails (P < 0.001). There was a negative correlation between the percentage of carcasses included in PDO and the LSI of tail (r = - 0.422; P < 0.001).ConclusionsIn conclusion, the presence of the undocked tail and the warm season can be considered risk factors for the prevalence of tail lesions, while long transport can increase limb lesions. Furthermore, the carcass weight and meat quality were negatively influenced by tail lesions

    Effect of Bacterial Infection on Ghrelin Receptor Regulation in Periodontal Cells and Tissues.

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    The effect of bacterial infection on the expression of growth hormone secretagogue receptor (GHS-R) was investigated in periodontal cells and tissues, and the actions of ghrelin were evaluated. GHS-R was assessed in periodontal tissues of rats with and without periodontitis. Human gingival fibroblasts (HGFs) were exposed to Fusobacterium nucleatum in the presence and absence of ghrelin. GHS-R expression was determined by real-time PCR and immunocytochemistry. Furthermore, wound healing, cell viability, proliferation, and migration were evaluated. GHS-R expression was significantly higher at periodontitis sites as compared to healthy sites in rat tissues. F. nucleatum significantly increased the GHS-R expression and protein level in HGFs. Moreover, ghrelin significantly abrogated the stimulatory effects of F. nucleatum on CCL2 and IL-6 expressions in HGFs and did not affect cell viability and proliferation significantly. Ghrelin stimulated while F. nucleatum decreased wound closure, probably due to reduced cell migration. Our results show original evidence that bacterial infection upregulates GHS-R in rat periodontal tissues and HGFs. Moreover, our study shows that ghrelin inhibited the proinflammatory actions of F. nucleatum on HGFs without interfering with cell viability and proliferation, suggesting that ghrelin and its receptor may act as a protective molecule during bacterial infection on periodontal cells

    Mass-Varying Neutrinos from a Variable Cosmological Constant

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    We consider, in a completely model-independent way, the transfer of energy between the components of the dark energy sector consisting of the cosmological constant (CC) and that of relic neutrinos. We show that such a cosmological setup may promote neutrinos to mass-varying particles, thus resembling a recently proposed scenario of Fardon, Nelson, and Weiner (FNW), but now without introducing any acceleronlike scalar fields. Although a formal similarity of the FNW scenario with the variable CC one can be easily established, one nevertheless finds different laws for neutrino mass variation in each scenario. We show that as long as the neutrino number density dilutes canonically, only a very slow variation of the neutrino mass is possible. For neutrino masses to vary significantly (as in the FNW scenario), a considerable deviation from the canonical dilution of the neutrino number density is also needed. We note that the present `coincidence' between the dark energy density and the neutrino energy density can be obtained in our scenario even for static neutrino masses.Comment: 8 pages, minor corrections, two references added, to apear in JCA

    Impact of comprehensive pulmonary rehabilitation on anxiety and depression in hospitalized COPD patients.

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    To prospectively evaluate the effect of inpatient pulmonary rehabilitation (iPR) on anxiety and depression as outcome measures in patients with COPD, we studied 149 consecutive adults COPD referred to our iPR after an exacerbation. Patients were divided according to the GOLD staging into: Group 1 (stage 2a, n = 48, FEV1 63 +/- 9% pred.), Group 2 (stage 2b, n = 53, FEV1 42 +/- 6% pred.) and Group 3 (stage 3, n = 48, FEV1 25 +/- 7% pred.). The iPR consisted of twelve 3-hours daily sessions. Hospital Anxiety Depression (HAD) Scale as well as 6-minute walk (6MWD) with evaluation of dyspnea (D) and leg fatigue (F) at rest and end of effort, and health related quality of life by means of St. George Respiratory Questionnaire (SGRQ) were assessed before (T0) and after (T1) the iPR. 6MWD, D and F at end of effort and SGRQ total score similarly improved (p < 0.001) in all groups after iPR. The mean level of HAD-anxiety (from 9.1 +/- 4.0 to 7.7 +/- 3.5, from 9.0 +/- 4.6 to 7.2 +/- 4.6 and from 8.1 +/- 4.1 to 6.7 +/- 4.3 in group 1,2 and 3 respectively) and HAD-depression (from 9.4 +/- 3.5 to 8.2 +/- 3.5, from 9.1 +/- 4.2 to 8.2 +/- 4.5 and from 9.0 +/- 4.0 to 7.4 +/- 4.5 respectively) similarly changed (p < 0.0001) over time in all groups. The total percentage of patients with abnormal score (> 10) of HAD-anxiety (from 31% to 21%) and HAD-depression (from 30% to 22%) significantly decreased (p < 0.05) after the iPR. Inpatient pulmonary rehabilitation may improve levels of anxiety and depression as well as symptoms, exercise capacity and health related quality of life in moderate to severe COPD patients after an acute exacerbation

    Dark matter powered stars: Constraints from the extragalactic background light

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    The existence of predominantly cold non-baryonic dark matter is unambiguously demonstrated by several observations (e.g., structure formation, big bang nucleosynthesis, gravitational lensing, and rotational curves of spiral galaxies). A candidate well motivated by particle physics is a weakly interacting massive particle (WIMP). Self-annihilating WIMPs would affect the stellar evolution especially in the early universe. Stars powered by self-annihilating WIMP dark matter should possess different properties compared with standard stars. While a direct detection of such dark matter powered stars seems very challenging, their cumulative emission might leave an imprint in the diffuse metagalactic radiation fields, in particular in the mid-infrared part of the electromagnetic spectrum. In this work the possible contributions of dark matter powered stars (dark stars; DSs) to the extragalactic background light (EBL) are calculated. It is shown that existing data and limits of the EBL intensity can already be used to rule out some DS parameter sets.Comment: Accepted for publication in ApJ; 7 pages, 5 figure

    Decaying into the Hidden Sector

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    The existence of light hidden sectors is an exciting possibility that may be tested in the near future. If DM is allowed to decay into such a hidden sector through GUT suppressed operators, it can accommodate the recent cosmic ray observations without over-producing antiprotons or interfering with the attractive features of the thermal WIMP. Models of this kind are simple to construct, generic and evade all astrophysical bounds. We provide tools for constructing such models and present several distinct examples. The light hidden spectrum and DM couplings can be probed in the near future, by measuring astrophysical photon and neutrino fluxes. These indirect signatures are complimentary to the direct production signals, such as lepton jets, predicted by these models.Comment: 40 pages, 5 figure

    Antimatter signals of singlet scalar dark matter

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    We consider the singlet scalar model of dark matter and study the expected antiproton and positron signals from dark matter annihilations. The regions of the viable parameter space of the model that are excluded by present data are determined, as well as those regions that will be probed by the forthcoming experiment AMS-02. In all cases, different propagation models are investigated, and the possible enhancement due to dark matter substructures is analyzed. We find that the antiproton signal is more easily detectable than the positron one over the whole parameter space. For a typical propagation model and without any boost factor, AMS-02 will be able to probe --via antiprotons-- the singlet model of dark matter up to masses of 600 GeV. Antiprotons constitute, therefore, a promising signal to constraint or detect the singlet scalar model.Comment: 24 pages, 8 figures. v2: minor improvements. Accepted for publication in JCA

    Environment-man relationships in historical times: the balance between urban development and natural forces at Leptis Magna (Libya).

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    We analyze the relationships between human modification of the environment and natural events in the Roman city of Leptis Magna (UNESCO world heritage), western Libya. For the first time the history of Leptis Magna is tested against a high resolution geo-morphological and stratigraphical reconstruction and absolute radiocarbon dating. Historical and archaeological sources indicate the occurrence of different natural events as the cause of the town decline: earthquakes, flooding, and tsunamis. Our data indicate that Leptis Magna was tightly linked to the nearby wadi. In fact, aware of the hazards related to violent flooding, the Romans were able to cope with the threat posed by the wadi by engineering defensive hydraulic works around the town. Once economic decay began and the society could no longer guarantee the ongoing maintenance of these structures, the decline of the settlement began and the occurrence of violent floods reclaimed the populated areas. The occurrence of large earthquakes, and the tsunami event that damaged the harbor have been discarded as playing a primary role in the decline of Leptis Magna
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