952 research outputs found

    An approximation approach to dynamic programming with unbounded returns

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    We study stochastic dynamic programming with recursive utility in settings where multiplicity of values is only attributed to unbounded returns. That is, we consider Koopmans aggregators that, when artificially restricted to be bounded, satisfy the traditional Blackwell’s discounting condition (as it certainly happens with time-additive aggregators). We argue that, when the truncation is removed, the sequence of truncated values converges to the relevant fixed point of the untruncated Bellman operator, whenever it exists, and diverges otherwise. The experiment provides a natural selection criterion, corresponding to an extension of the recursive utility from bounded to unbounded returns

    Measurement of the KSπeνK_{S}\to \pi e\nu branching fraction with the KLOE experiment

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    The ratio R=Γ(KSπev)/Γ(KSπ+π)\mathcal{R}=\Gamma (K_{S} \to \pi ev)/\Gamma (K_{S} \to \pi ^{+}\pi ^{-}) has been measured with a sample of 300 million KSK_{S} mesons produced in ϕKLKS\phi \to K_{L}K_{S} decays recorded by the KLOE experiment at the DAΦNE e+^{+}e^{-} collider. KSπevK_{S} \to \pi ev events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of KLπevK_{L} \to \pi ev decays are used to evaluate signal selection efficiencies. With 49647 ± 316 signal events we measure R\mathcal{R} = (1.0421 ± 0.0066stat_{stat} ± 0.0075syst)×_{syst}) \times 103^{−3}. The combination with our previous measurement gives R\mathcal{R} = (1.0338 ± 0.0054stat_{stat} ± 0.0064syst)×_{syst}) \times 103^{−3}. From this value we derive the branching fraction B(KSπev)\mathcal{B}(K_{S} \to \pi ev) = (7.153 ± 0.037stat_{stat} ± 0.044syst)×_{syst}) \times 104^{−4} and f+_{+}(O) Vus\left|V_{us} \right| = 0.2170 ± 0.009

    Direct tests of T, CP, CPT symmetries in transitions of neutral K mesons with the KLOE experiment

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    Tests of the T, CP and CPT symmetries in the neutral kaon system are performed by the direct comparison of the probabilities of a kaon transition process to its symmetry-conjugate. The exchange of in and out states required for a genuine test involving an antiunitary transformation implied by time-reversal is implemented exploiting the entanglement of K0K‾0 pairs produced at a ϕ-factory.A data sample collected by the KLOE experiment at DAΦNE corresponding to an integrated luminosity of about 1.7 fb−1 is analysed to study the Δt distributions of the ϕ→KSKL→π+π−π±e∓ν and ϕ→KSKL→π±e∓ν3π0 processes, with Δt the difference of the kaon decay times. A comparison of the measured Δt distributions in the asymptotic region Δt≫τS allows to test for the first time T and CPT symmetries in kaon transitions with a precision of few percent, and to observe CP violation with this novel method

    Mu2e Run I Sensitivity Projections for the Neutrinoless mu(-) -> e(-) Conversion Search in Aluminum

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    The Mu2e experiment at Fermilab will search for the neutrinoless μ−→e− conversion in the field of an aluminum nucleus. The Mu2e data-taking plan assumes two running periods, Run I and Run II, separated by an approximately two-year-long shutdown. This paper presents an estimate of the expected Mu2e Run I search sensitivity and includes a detailed discussion of the background sources, uncertainties of their prediction, analysis procedures, and the optimization of the experimental sensitivity. The expected Run I 5σ discovery sensitivity is Rμe=1.2×10−15, with a total expected background of 0.11±0.03 events. In the absence of a signal, the expected upper limit is Rμe&lt;6.2×10−16 at 90% CL. This represents a three order of magnitude improvement over the current experimental limit of Rμe&lt;7×10−13 at 90% CL set by the SINDRUM II experiment.</jats:p

    Measurement of the KS → πeν branching fraction with the KLOE experiment

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    The ratio R = Gamma(KS -&gt; pi e nu)/Gamma(KS -&gt; pi+pi−) has been measured with a sample of 300 million KS mesons produced in phi -&gt; KLKS decays recorded by the KLOE experiment at the DAFNE e+e− collider. KS -&gt; pi e nu  events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of KL -&gt; pi e nu decays are used to evaluate signal selection efficiencies. With 49647±316 signal events we measure R = (1.0421 ± 0.0066stat ± 0.0075syst)×10^−3. The combination with our previous measurement gives R = (1.0338 ± 0.0054stat ± 0.0064syst) × 10^−3. From this value we derive the branching fraction B(KS -&gt; pi e nu) = (7.153 ± 0.037stat ± 0.044syst)×10^−4 and f+(0)|Vus| = 0.2170 ± 0.009

    Human Ovarian Follicular Fluid Mesenchymal Stem Cells Express Osteogenic Markers When Cultured on Bioglass 58S-Coated Titanium Scaffolds

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    Recent studies have reported that stem cells (human follicular fluid mesenchymal stem cells or hFF-MSCs) are present in ovarian follicular fluid (hFF) and that they have a proliferative and differentiative potential which is similar to that of MSCs derived from other adult tissue. These mesenchymal stem cells, isolated from human follicular fluid waste matter discarded after retrieval of oocytes during the IVF process, constitute another, as yet unutilized, source of stem cell materials. There has been little work on the compatibility of these hFF-MSCs with scaffolds useful for bone tissue engineering applications and the aim of this study was to evaluate the osteogenic capacity of hFF-MSCs seeded on bioglass 58S-coated titanium and to provide an assessment of their suitability for bone tissue engineering purposes. Following a chemical and morphological characterization with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), cell viability, morphology and expression of specific osteogenic markers were examined after 7 and 21 days of culture. The hFF-MSCs seeded on bioglass and cultured with osteogenic factors, when compared with those seeded on tissue culture plate or on uncoated titanium, exhibited enhanced cell viability and osteogenic differentiation, as reflected by increased calcium deposition and increased ALP activity with expression and production of bone-related proteins. Taken together, these results demonstrate that MSCs from human follicular fluid waste materials can be easily cultured in titanium scaffolds coated with bioglass, having osteoinductive properties. This process has significant potential for regenerative medicine applications and indicates that hFF-MSCs may be a valid alternative to hBM-MSC cells in experimental models in bone tissue engineering

    The first report of the Italian Migraine Registry (I-GRAINE)

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    Italian Migraine Registry (I-GRAINE) is a multicenter (n = 38), prospective, observational, non-interventional study aimed at providing big data on migraine to ensure proper clinical disease management, according to scientific, and sustainability criteria. We enrolled consecutive patients affected by episodic or chronic migraine according to the systematic random method. Information on sociodemographic characteristics, lifestyle, migraine features, patient’s journey, and healthcare resource use were gathered using face-to-face interviews. On the date of 31 December 2021, we enrolled 231 patients at 12 headache centers. Most of them were women (84.4%), with high migraine frequency (9.6 ± 6.9&nbsp;days/month) and severe disability (MIDAS score: 43.0 ± 40.8; HIT-6 score: 60.4 ± 10.6). Only a minority of patients (38.1%) had previously visited a headache center. A clear-cut difference emerged in the proportion of responders to nonspecific acute treatments (43.5–66.7%) compared to triptans (76.3%) and in responders to unspecific prophylaxis (5.4–35%) compared to anti-CGRP monoclonal antibodies (69.2–78.6%). Most patients underwent ≥ 1 specialist visit (66.9%) or diagnostic investigation (77.4%) over the last 3&nbsp;years—mostly subsidized by our national health system—inappropriate in 64.9% and 25% of the cases, respectively. The I-GRAINE registry is expected to provide a large and exponentially increasing collection of clinical, biological, and epidemiologic information and will contribute to moving migraine out of the shadow cone of marginalization, which has been often relegated up to now

    Cross-sectional survey on BNT162b2 mRNA COVID-19 vaccine serious adverse events in children 5 to 11 years of age. A monocentric experience

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    Objective: Our aim was to evaluate the safety of COVID-19 vaccine in children resident in the Latina Local Health Authority. Methods: We conducted a telephone survey among children aged 5–11 years receiving BNT162b2 mRNA COVID-19 vaccine between December 15 and 21. The main outcomes included the presence of allergic reactions or anaphylaxis, adverse events after 24–48 h, 7 and 20 days of taking the first and second doses of medications, and documented SARS-CoV-2 infection after vaccination. The information obtained was automatically linked to a spreadsheet and analyzed. Results: 569 children were enrolled. The mean age was 114 ± 4.24 months; there were 251 males in the study. The vaccine showed a favorable safety profile; no anaphylaxis or serious adverse events were reported. The most common symptoms both after the first and second dose were injection site reactions, asthenia, and headache. Injection site reactions were more frequent after the first dose (p = 0.01), while systemic symptoms were more frequent after the second dose (p = 0.022). These symptoms were more frequent in patients with comorbidities (p = 0.0159). Conclusion: Our findings confirm the safety of COVID-19 vaccine in children younger 11 years and could be useful to promote its diffusion in pediatric ages in order to achieve “herd immunity” and prevent the virus’s circulation
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