509 research outputs found

    Comparative analysis of the Λb→Λℓ+ℓ−\Lambda_b \rightarrow \Lambda \ell^+ \ell^- decay in the SM, SUSY and RS model with custodial protection

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    We comparatively analyze the rare Λb→Λℓ+ℓ−\Lambda _b\rightarrow \Lambda \ell^+ \ell^- channel in standard model, supersymmetry and Randall-Sundrum model with custodial protection (RSc_c). Using the parametrization of the matrix elements entering the low energy effective Hamiltonian in terms of form factors, we calculate the corresponding differential decay width and lepton forward-backward asymmetry in these models. We compare the results obtained with the most recent data from LHCb as well as lattice QCD results on the considered quantities. It is obtained that the standard model, with the form factors calculated in light-cone QCD sum rules, can not reproduce some experimental data on the physical quantities under consideration but the supersymmetry can do it. The RSc_c model predictions are roughly the same as the standard model and there are no considerable differences between the predictions of these two models. In the case of differential decay rate, the data in the range 44 GeV2/^2/c4≤^4\leq q2≤6q^2 \leq 6 GeV2/^2/c4^4 can not be described by any of the considered models.Comment: 28 Pages, 12 Figures and 3 Table

    Analysis of the semileptonic Λb→Λℓ+ℓ−\Lambda_b\rightarrow \Lambda \ell^+ \ell^- transition in topcolor-assisted technicolor (TC2) model

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    We comparatively analyze the flavor changing neutral current process of the Λb→Λℓ+ℓ−\Lambda_b \rightarrow \Lambda \ell^+ \ell^- in the standard model as well as topcolor-assisted technicolor model using the form factors calculated via light cone QCD sum rules in full theory. In particular, we calculate the decay width, branching ratio and lepton forward-backward asymmetry related to this decay channel. We compare the results of the topcolor-assisted technicolor model with those of the standard model and debate how the results of the topcolor-assisted technicolor model depart from the standard model predictions. We also compare our results on the differential branching ratio with recent experimental data provided by CDF and LHCb Collaborations.Comment: 29 Pages, 16 Figures and 8 Table

    Plant Seed : A Pertinent Model to Study Aging Processes

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    Seeds are the major form of dispersal of plants in the environment. Seeds of many plant species are exceptionally adapted to harsh environmental conditions provided they are in a state of desiccation. Spectacular cases of seed longevity have been reported. It’s one of the singular case of pluricellular, differentiate eukaryotic organ able to survive several years in anhydrobiosis. Plant scientific community explore these fascinating aspects of seed aging thanks to the immense possibilities now offered to create/modify plants at a much faster rate and in a more accurate way than through classical and molecular genetic approaches and genomic tools. These investigations allowed unveiling seed specificities against aging processe

    Performance and meat quality characteristics of male quails (Coturnix coturnix japonica) fed diets supplemented with pomegranate seed oil

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    Pomegranate seed oil (PSO) is a nutritive, antioxidant-rich by-product, and it has been tested as a feed ingredient for livestock. However, studies on quails are scarce. The current study investigated that the effect of PSO on the performance and meat instrumental quality of quails. Area of study: Türkiye. Material and methods: A total of 60 seventy-day-old male quails were equally subjected to 3 dietary treatments con-sisting of 20 birds (5 replicates with 4 birds each). The quails were fed a diet supplemented with 0, 100, and 200 mg kg-1 pomegranate seed oil (PSO). After 10 weeks, two birds per subgroup were randomly selected and slaughtered. Main results: Supplementation of PSO reduced (p<0.05) feed intake and body weight gain linearly. However, there was no significant effect of PSO on carcass traits. For color parameters, the L* and b* values of breast and thigh meat increased with the addition of PSO to the diet (p<0.05). Cooking losses were highest in the thigh of quails fed 200 mg kg-1 PSO. On the other hand, in the breast, the lowest values for this parameter were observed in the groups that had received 100 mg kg-1 of PSO. Research highlights: Including 100 mg kg-1 of PSO can improve some meat quality characteristics without affecting performance parameters. There is a possibility that meat quality could be negatively affected by values higher than this. Nevertheless, further research is needed to determine the optimal dose of PSO to improve quail meat quality and its performance

    THE EFFECTS OF WHOLE BODY VIBRATION ON POSTURAL CONTROL: THE FREQUENCY OF STIMULATION

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    This study investigated the efficacy of high and low-frequency acute whole-body vibration (WBV) on postural control ability. WBV stimulus were applied the following determinants: (1) type (vertical) (2) frequency (30 and 40 Hz), (3) stance position (static squat position), (4) amplitude (4mm mm), (5) knee flexion angle (120°) and time (60s).Motion of the point of application of the vertical component [medio-lateral (ML) and anterio-posterior (AP)] of the ground reaction force (center of pressure, COP). The study results showed that static WBV stimuli given at low and high frequencies and 4 mm amplitude resulted in a different postural adaptation (

    Liquefaction Potential of Railway Embankments

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    This paper presents an overview of the nature of train-induced vibrations and discusses the liquefaction potential of railway embankments under such low-level vibrations. The paper also presents the results of static and dynamic finite difference numerical analyses performed for a simple railway embankment geometry. The liquefaction potential for the railway embankment foundation was estimated using the results corn FLAC numerical analyses, as well as a cyclic shear stress liquefaction resistance approach using a modified cyclic resistance ratio curve. Liquefaction of railway embankment foundations was found to be possible. However, based on the majority of reported failures the liquefaction potential remains low unless the train-induced vibrations are coupled with factors such as loose foundation, and sudden rise of pore water pressures due to poor drainage, flooding, or heavy rainfall

    A Case for Self-Managing DRAM Chips: Improving Performance, Efficiency, Reliability, and Security via Autonomous in-DRAM Maintenance Operations

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    The memory controller is in charge of managing DRAM maintenance operations (e.g., refresh, RowHammer protection, memory scrubbing) in current DRAM chips. Implementing new maintenance operations often necessitates modifications in the DRAM interface, memory controller, and potentially other system components. Such modifications are only possible with a new DRAM standard, which takes a long time to develop, leading to slow progress in DRAM systems. In this paper, our goal is to 1) ease, and thus accelerate, the process of enabling new DRAM maintenance operations and 2) enable more efficient in-DRAM maintenance operations. Our idea is to set the memory controller free from managing DRAM maintenance. To this end, we propose Self-Managing DRAM (SMD), a new low-cost DRAM architecture that enables implementing new in-DRAM maintenance mechanisms (or modifying old ones) with no further changes in the DRAM interface, memory controller, or other system components. We use SMD to implement new in-DRAM maintenance mechanisms for three use cases: 1) periodic refresh, 2) RowHammer protection, and 3) memory scrubbing. We show that SMD enables easy adoption of efficient maintenance mechanisms that significantly improve the system performance and energy efficiency while providing higher reliability compared to conventional DDR4 DRAM. A combination of SMD-based maintenance mechanisms that perform refresh, RowHammer protection, and memory scrubbing achieve 7.6% speedup and consume 5.2% less DRAM energy on average across 20 memory-intensive four-core workloads. We make SMD source code openly and freely available at [128]

    Ramulator 2.0: A Modern, Modular, and Extensible DRAM Simulator

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    We present Ramulator 2.0, a highly modular and extensible DRAM simulator that enables rapid and agile implementation and evaluation of design changes in the memory controller and DRAM to meet the increasing research effort in improving the performance, security, and reliability of memory systems. Ramulator 2.0 abstracts and models key components in a DRAM-based memory system and their interactions into shared interfaces and independent implementations. Doing so enables easy modification and extension of the modeled functions of the memory controller and DRAM in Ramulator 2.0. The DRAM specification syntax of Ramulator 2.0 is concise and human-readable, facilitating easy modifications and extensions. Ramulator 2.0 implements a library of reusable templated lambda functions to model the functionalities of DRAM commands to simplify the implementation of new DRAM standards, including DDR5, LPDDR5, HBM3, and GDDR6. We showcase Ramulator 2.0's modularity and extensibility by implementing and evaluating a wide variety of RowHammer mitigation techniques that require different memory controller design changes. These techniques are added modularly as separate implementations without changing any code in the baseline memory controller implementation. Ramulator 2.0 is rigorously validated and maintains a fast simulation speed compared to existing cycle-accurate DRAM simulators. Ramulator 2.0 is open-sourced under the permissive MIT license at https://github.com/CMU-SAFARI/ramulator

    Influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and Emiliania huxleyi

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    Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results of laboratory experiments, showing that trace metal release from different volcanic materials can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean. Highlights: â–º We tested the effect of volcanic ash on growth of T. pseudonana and E. huxleyi â–º Volcanic ash increased growth of T. pseudonana but not of E. huxleyi â–º Mn seems important to regulate the effects of different trace metals from the ash â–º Volcanic eruptions have the potential to change phytoplankton community structure
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