3,341 research outputs found

    Masses and decay constants of Bc(∗)B_c^{(*)} mesons with Nf=2+1+1N_f=2+1+1 twisted mass fermions

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    We present a preliminary lattice determination of the masses and decay constants of the pseudoscalar and vector mesons BcB_c and Bc∗B_c^*. Our analysis is based on the gauge configurations produced by the European Twisted Mass Collaboration with Nf=2+1+1N_f = 2 + 1 + 1 flavors of dynamical quarks. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV. Heavy-quark masses are simulated directly on the lattice up to ∼3\sim 3 times the physical charm mass. The physical b-quark mass is reached using the ETMC ratio method. Our preliminary results are: MBc=6341 (60)M_{B_c} = 6341\,(60) MeV, fBc=396 (12)f_{B_c} = 396\,(12) MeV, MBc∗/MBc=1.0037 (39)M_{B_c^*} / M_{B_c} = 1.0037\,(39) and fBc∗/fBc=0.987 (7)f_{B_c^*} / f_{B_c} = 0.987\,(7).Comment: 7 pages, 3 figures, 1 table; contribution to the proceedings of the XXXVI Int'l Workshop on Lattice Field Theory (LATTICE2018), July 22-28, 2018, East Lansing, Michigan State University (Michigan, USA

    Metabolomics application in maternal-fetal medicine

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    Metabolomics in maternal-fetal medicine is still an "embryonic" science. However, there is already an increasing interest in metabolome of normal and complicated pregnancies, and neonatal outcomes. Tissues used for metabolomics interrogations of pregnant women, fetuses and newborns are amniotic fluid, blood, plasma, cord blood, placenta, urine, and vaginal secretions. All published papers highlight the strong correlation between biomarkers found in these tissues and fetal malformations, preterm delivery, premature rupture of membranes, gestational diabetes mellitus, preeclampsia, neonatal asphyxia, and hypoxic-ischemic encephalopathy. The aim of this review is to summarize and comment on original data available in relevant published works in order to emphasize the clinical potential of metabolomics in obstetrics in the immediate future

    Controlled flavor violation in the MSSM from a unified Δ(27)\Delta(27) flavor symmetry

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    We study the phenomenology of a unified supersymmetric theory with a flavor symmetry Δ(27)\Delta(27). The model accommodates quark and lepton masses, mixing angles and CP phases. In this model, the Dirac and Majorana mass matrices have a unified texture zero structure in the (1,1)(1,1) entry that leads to the Gatto-Sartori-Tonin relation between the Cabibbo angle and ratios of the masses in the quark sectors, and to a natural departure from zero of the θ13ℓ\theta_{13}^\ell angle in the lepton sector. We derive the flavor structures of the trilinears and soft mass matrices, and show their general non-universality. This causes large flavor violating effects. As a consequence, the parameter space for this model is constrained, allowing it to be (dis)proven by flavor violation searches in the next decade. Although the results are model specific, we compare them to previous studies to show similar flavour effects (and associated constraints) are expected in general in supersymmetric flavor models, and may be used to distinguish them.Comment: 21 pages, 6 figure

    Leptogenesis in Δ(27)\Delta(27) with a Universal Texture Zero

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    We investigate the possibility of viable leptogenesis in an appealing Δ(27)\Delta(27) model with a universal texture zero in the (1,1) entry. The model accommodates the mass spectrum, mixing and CP phases for both quarks and leptons and allows for grand unification. Flavoured Boltzmann equations for the lepton asymmetries are solved numerically, taking into account both N1N_1 and N2N_2 right-handed neutrino decays. The N1N_1-dominated scenario is successful and the most natural option for the model, with M1∈[109,1012]M_1 \in [10^9, 10^{12}] GeV, and M1/M2∈[0.002,0.1]M_1/M_2 \in [0.002, 0.1], which constrains the parameter space of the underlying model and yields lower bounds on the respective Yukawa couplings. Viable leptogenesis is also possible in the N2N_2-dominated scenario, with the asymmetry in the electron flavour protected from N1N_1 washout by the texture zero. However, this occurs in a region of parameter space which has a stronger mass hierarchy M1/M2<0.002M_1/M_2 < 0.002 , and M2M_2 relatively close to M3M_3, which is not a natural expectation of the Δ(27)\Delta(27) model.Comment: v2: 20 pages, 2 figures. Version accepted in JHE

    Noisy Neighbors: Efficient membership inference attacks against LLMs

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    The potential of transformer-based LLMs risks being hindered by privacy concerns due to their reliance on extensive datasets, possibly including sensitive information. Regulatory measures like GDPR and CCPA call for using robust auditing tools to address potential privacy issues, with Membership Inference Attacks (MIA) being the primary method for assessing LLMs’ privacy risks. Differently from traditional MIA approaches, often requiring computationally intensive training of additional models, this paper introduces an efficient methodology that generates noisy neighbors for a target sample by adding stochastic noise in the embedding space, requiring operating the target model in inference mode only. Our findings demonstrate that this approach closely matches the effectiveness of employing shadow models, showing its usability in practical privacy auditing scenarios

    The Chemical Composition of an Extrasolar Minor Planet

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    We report the relative abundances of 17 elements in the atmosphere of the white dwarf star GD 362, material that, very probably, was contained previously in a large asteroid or asteroids with composition similar to the Earth/Moon system. The asteroid may have once been part of a larger parent body not unlike one of the terrestrial planets of our solar system.Comment: ApJ, in pres

    Volcaniclastic sedimentation in a closed, marginal rift basin: the case of the Melka Kunture area (Upper Awash, ethiopia)

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    The upper Awash runs across a volcano-sedimentary succession dated from the Early to Middle Pleistocene and located on the western margin of the northern portion of the Main Ethiopian Rift. The succession lies above Late Miocene to Pliocene lava flows, domes and large volume ignimbrites. The succession formed within a fluvial system that developed within transversal rift faults. The stratigraphy consists of primary volcanic deposits interbedded with reworked sediments emplaced in a low-energy floodplain developed in a subsiding area. The lower part of the volcaniclastic sequence is dominated by a 1.2 Ma old, low aspect ratio, pyroclastic density current deposit (Kella ignimbrite). This eruption was followed by an eruptive stasis and reorganization of the drainage system. Tephra deposition in the floodplain climaxed again between 0.9 and 0.7 Ma and was associated with extensive tephra reworking. Sedimentation rates significantly decreased after 0.6 myr ago, probably owing to declining volcanic activity. Dynamic interaction between tectonics and volcanic activity created a complex sedimentary environment preserving numerous artefacts (lithic tools), animal and hominin remains. Stratigraphic correlation is based on the interpretation of the basin evolution and has relevance for the reconstruction of the palaeoenvironment and the interpretation of the palaeontological and archaeological data
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