3,430 research outputs found

    Dijet resonance from leptophobic Z' and light baryonic cold dark matter

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    In light of the recent CDF report on the excess in the Wjj channel, we analyze (non)supersymmetric U(1)_B x U(1)_L model, interpreting the dijet peak as a leptophobic U(1)_B gauge boson. If this excess is confirmed, it has an interesting implication for the baryonic cold dark matter (CDM) in the model: there should be light CDM with a few GeV mass, and direct detection cross section at the level of a few x 10^{-2} pb.Comment: 5 pages, 3 figures, version published in Phys. Lett.

    Understanding and Improving In-Context Learning on Vision-language Models

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    Recently, in-context learning (ICL) on large language models (LLMs) has received great attention, and this technique can also be applied to vision-language models (VLMs) built upon LLMs. These VLMs can respond to queries by conditioning responses on a series of multimodal demonstrations, which comprise images, queries, and answers. Though ICL has been extensively studied on LLMs, its research on VLMs remains limited. The inclusion of additional visual information in the demonstrations motivates the following research questions: which of the two modalities in the demonstration is more significant? How can we select effective multimodal demonstrations to enhance ICL performance? This study investigates the significance of both visual and language information. Our findings indicate that ICL in VLMs is predominantly driven by the textual information in the demonstrations whereas the visual information in the demonstrations barely affects the ICL performance. Subsequently, we provide an understanding of the findings by analyzing the model information flow and comparing model inner states given different ICL settings. Motivated by our analysis, we propose a simple yet effective approach, termed Mixed Modality In-Context Example Selection (MMICES), which considers both visual and language modalities when selecting demonstrations and shows better ICL performance. Extensive experiments are conducted to support our findings, understanding, and improvement of the ICL performance of VLMs.Comment: 8 pages, 10 figure

    Design, Synthesis, and Characterization of Brequinar Conjugates as Probes to Study DHODH Inhibition

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    Brequinar, a potent dihydroorotate dehydrogenase (DHODH) inhibitor, has been evaluated in multiple clinical trials as a potential treatment for cancer. To further understand brequinar‐based DHODH inhibition and DHODH′s therapeutic relevance in cancer, we have developed novel brequinar‐based probes. We disclose a 16‐step convergent synthesis of the first brequinar‐PROTAC and a four‐step approach towards the first mitochondrial‐directed brequinar probe. A PROTAC and mitochondria‐directed probe of brequinar both possess cytotoxicity that is superior to brequinar in a colony formation assay.Brequin′ news: A novel convergent synthesis of brequinar‐based probes to induce protein degradation (16 steps) and improve mitochondria accumulation (four steps) is disclosed.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138895/1/chem201702999_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138895/2/chem201702999-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138895/3/chem201702999.pd

    Pure Leptonic Gauge Symmetry, Neutrino Masses and Dark Matter

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    A possible extension of the Standard Model to include lepton number as local gauge symmetry is investigated. In such a model, anomalies are canceled by two extra fermions doublet. After leptonic gauge symmetry spontaneously broken, three active neutrinos may acquire non-zero Majorana masses through the modified Type-II seesaw mechanism. Constraints on the model from electro-weak precision measurements are studied. Due to the Z2Z_2 discrete flavor symmetry, right-handed Majorana neutrinos can serve as cold dark matter candidate of the Universe. Constraint from dark matter relic abundance is calculated.Comment: 13 pages, 2 figures; typos corrected, comments and references added, to appear in Phys. Lett.

    Magnetic Reversal on Vicinal Surfaces

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    We present a theoretical study of in-plane magnetization reversal for vicinal ultrathin films using a one-dimensional micromagnetic model with nearest-neighbor exchange, four-fold anisotropy at all sites, and two-fold anisotropy at step edges. A detailed "phase diagram" is presented that catalogs the possible shapes of hysteresis loops and reversal mechanisms as a function of step anisotropy strength and vicinal terrace length. The steps generically nucleate magnetization reversal and pin the motion of domain walls. No sharp transition separates the cases of reversal by coherent rotation and reversal by depinning of a ninety degree domain wall from the steps. Comparison to experiment is made when appropriate.Comment: 12 pages, 8 figure

    A mixed‐method systematic review of the effectiveness and acceptability of preoperative psychological preparation programmes to reduce paediatric preoperative anxiety in elective surgery

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    Aim To explore the effectiveness of preoperative psychological preparation programmes aimed to reduce paediatric preoperative anxiety and the potential factors that could have an impact on parent and children's acceptance of such interventions. Background Various preoperative psychological preparation programmes are available to address paediatric preoperative anxiety. No mixed‐method review has been conducted to explore the effectiveness and acceptability of these programmes. Design A mixed‐method systematic review. Data sources Seven bibliographic databases were searched from inception to September 2016, complemented by hand searching of key journals, the reference lists of relevant reviews, search for grey literature and the contacting of associated experts. Review methods The review process was conducted based on the framework developed by the Evidence for Policy and Practice Information and Co‐ordinating Centre. A narrative summary and a thematic synthesis were developed to synthesise the quantitative and qualitative data respectively, followed by a third synthesis to combine the previous syntheses. Results Nineteen controlled trials and eleven qualitative studies were included for data synthesis. The controlled trials reveal that educational multimedia applications and web‐based programmes may reduce paediatric preoperative anxiety, while the effectiveness of therapeutic play and books remains uncertain. Qualitative studies showed parent‐child dyads seek different levels of information. Conclusions Providing matched information provision to each parent and child, actively involving children and their parents and teaching them coping skills, may be the essential hallmarks of a successful preoperative psychological preparation. Further research is necessary to confirm the effectiveness of therapeutic play and books

    Spin and Chirality Effects in Antler-Topology Processes at High Energy e+ee^+e^- Colliders

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    We perform a model-independent investigation of spin and chirality correlation effects in the antler-topology processes e+eP+P(+D0)(Dˉ0)e^+e^-\to\mathcal{P}^+\mathcal{P}^-\to (\ell^+ \mathcal{D}^0) (\ell^-\mathcal{\bar{D}}^0) at high energy e+ee^+e^- colliders with polarized beams. Generally the production process e+eP+Pe^+e^-\to\mathcal{P}^+\mathcal{P}^- can occur not only through the ss-channel exchange of vector bosons, V0\mathcal{V}^0, including the neutral Standard Model (SM) gauge bosons, γ\gamma and ZZ, but also through the ss- and tt-channel exchanges of new neutral states, S0\mathcal{S}^0 and T0\mathcal{T}^0, and the uu-channel exchange of new doubly-charged states, U\mathcal{U}^{--}. The general set of (non-chiral) three-point couplings of the new particles and leptons allowed in a renormalizable quantum field theory is considered. The general spin and chirality analysis is based on the threshold behavior of the excitation curves for P+P\mathcal{P}^+\mathcal{P}^- pair production in e+ee^+e^- collisions with longitudinal and transverse polarized beams, the angular distributions in the production process and also the production-decay angular correlations. In the first step, we present the observables in the helicity formalism. Subsequently, we show how a set of observables can be designed for determining the spins and chiral structures of the new particles without any model assumptions. Finally, taking into account a typical set of approximately chiral invariant scenarios, we demonstrate how the spin and chirality effects can be probed experimentally at a high energy e+ee^+e^- collider.Comment: 50 pages, 14 figures, 6 tables, matches version published in EPJ
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