270 research outputs found

    Heavy-quark potential in Gribov-Zwanziger approach around deconfinement phase transition

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    The interaction potential between a pair of heavy quarks is calculated with resummed perturbation method in Gribov-Zwanziger approach at finite temperature. The resummed loop correction makes the potential complex. While the real part is, as expected, screened and becomes short-ranged in hot medium, the strength of the imaginary part increases with temperature and is comparable with the real part, which is very different from the previous calculation in HTL approach. This means that, both the color screening and Landau damping play important role in the dissociation of heavy flavor hadrons in hot medium.Comment: 6 pages, 7 figure

    Identification of suitable reference genes for miRNA quantitation in bumblebee (Hymenoptera: Apidae) response to reproduction

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    International audienceAbstractThe precise quantification of microRNAs (miRNAs) expression level is a critical factor in mastering its functions. We evaluate the suitability of two common genes and ten miRNAs as normalizers for miRNA quantification in the head and ovary at different reproductive status of bumblebees, Bombus lantschouensis by using four different algorithms and one consensus rank approach. For the head and ovary combination, miR-275 was the best candidate. For different tissues, miR-275 was the most stable candidate in the head, while the candidate for the ovary was miR-277. To test the best candidate accuracy, miR-315 was demonstrated to be downregulated based on miR-275 normalization in ovipositor bumblebees. The miR-275 and miR-277 combination is identified to be the most reliable and suitable reference genes for the head and ovary of bumblebees

    Network and cellular mechanisms underlying heterogeneous excitatory/inhibitory balanced states

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    Recent work has explored spatiotemporal relationships between excitatory (E) and inhibitory (I) signaling within neural networks, and the effect of these relationships on network activity patterns. Data from these studies have indicated that excitation and inhibition are maintained at a similar level across long time periods and that excitatory and inhibitory currents may be tightly synchronized. Disruption of this balance—leading to an aberrant E/I ratio—is implicated in various brain pathologies. However, a thorough characterization of the relationship between E and I currents in experimental settings is largely impossible, due to their tight regulation at multiple cellular and network levels. Here, we use biophysical neural network models to investigate the emergence and properties of balanced states by heterogeneous mechanisms. Our results show that a network can homeostatically regulate the E/I ratio through interactions among multiple cellular and network factors, including average firing rates, synaptic weights and average neural depolarization levels in excitatory/inhibitory populations. Complex and competing interactions between firing rates and depolarization levels allow these factors to alternately dominate network dynamics in different synaptic weight regimes. This leads to the emergence of distinct mechanisms responsible for determining a balanced state and its dynamical correlate. Our analysis provides a comprehensive picture of how E/I ratio changes when manipulating specific network properties, and identifies the mechanisms regulating E/I balance. These results provide a framework to explain the diverse, and in some cases, contradictory experimental observations on the E/I state in different brain states and conditions.Network can homeostatically regulate the E/I ratio and net post‐synaptic current through interactions among multiple cellular and network factors, including average firing rates, synaptic weights and average neural depolarization levels in excitatory/inhibitory neuronal populations, leading to the emergence of distinct mechanisms responsible for determining a balanced E/I state and its dynamical correlate. This in turn leads to the emergence of multiple balance states having different dynamical properties.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154922/1/ejn14669_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154922/2/ejn14669-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154922/3/ejn14669.pd

    Joint 3D Deployment and Resource Allocation for UAV-assisted Integrated Communication and Localization

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    In this paper, we investigate an unmanned aerial vehicle (UAV)-assisted integrated communication and localization network in emergency scenarios where a single UAV is deployed as both an airborne base station (BS) and anchor node to assist ground BSs in communication and localization services. We formulate an optimization problem to maximize the sum communication rate of all users under localization accuracy constraints by jointly optimizing the 3D position of the UAV, and communication bandwidth and power allocation of the UAV and ground BSs. To address the intractable localization accuracy constraints, we introduce a new performance metric and geometrically characterize the UAV feasible deployment region in which the localization accuracy constraints are satisfied. Accordingly, we combine Gibbs sampling (GS) and block coordinate descent (BCD) techniques to tackle the non-convex joint optimization problem. Numerical results show that the proposed method attains almost identical rate performance as the meta-heuristic benchmark method while reducing the CPU time by 89.3%.Comment: The paper has been accepted for publication by IEEE Wireless Communications Letter

    Facile Preparation of Bimetallic MOF-derived Supported Tungstophosphoric Acid Composites for Biodiesel Production

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    In this work, the novel TPA@C-NiZr-MOF catalyst is synthesized by the impregnation of tungstophosphoric acid (TPA) on the NiZr-based metal-organic framework (NiZr-MOF) followed by calcination up to 300 °C. The as-prepared catalyst materials were structurally, morphologically, and texturally characterized by XRD, FTIR, temperature programmed desorption of NH3 ( TPD-NH3 ), N2 physisorption, SEM, TEM, and XPS. The prepared catalyst can be used as an efficient heterogeneous catalyst for biodiesel production from oleic acid (OA) with methanol. The results indicated that, in comparison to TPA@NiZr-MOF, the TPA@C-NiZr-MOF catalyst calcined at 300 °C exhibits excellent catalytic performance probably owing to the synergistic effect between TPA and metal oxide skeletons, high acidity, as well as larger surface area and pore size. Additionally, the TPA@C-NiZr-MOF catalyst can be reused in up to six cycles with an acceptable conversion. This study showed that the bimetallic MOF-derived composite materials can be used as an alternative potential heterogeneous catalyst toward biorefinery applications

    First Characterization of Sphingomyeline Phosphodiesterase Expression in the Bumblebee, Bombus lantschouensis

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      The bumblebee (Bombus lantschouensis Vogt) is an important pollinator of wild plants. Sphingomyelin phosphodiesterase (SMPD) is a hydrolase that plays a major role in sphingolipid metabolism reactions. We report the preparation and characterization of a polyclonal antibody for bumblebee SMPD. We then use the polyclonal antiserum to detect the SMPD protein at different development stages and in different tissues. Our results showed that a 1228bp fragment homologous with the B. terrestris SMPD gene was successfully amplified. The molecular weight of the fusion protein was about 70 kDa by SDS-PAGE. An effective polyclonal antibody against SMPD was also obtained from mice and found to have a higher specificity for bumblebee SMPD. Western blotting detection showed that SMPD was expressed at a high level in queen ovaries, although expression was lower in the midgut and venom gland. SMPD expression decreased from the egg stage until the pdd stage. We interpret our results as showing that the development of an effective polyclonal antiserum for the SMPD protein of a bumblebee, which provides a tool for exploring the function of the SMPD gene. In addition, the work has confirmed that SMPD should be considered as an important enzyme during bumblebee egg and larval stages

    Prediction of the post-translational modifications of adipokinetic hormone receptors from solitary to eusocial bees

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    Adipokinetic hormone receptor (AKHR) was regarded as the crucial regulator of lipid consuming, but now has been renewed as a pluripotent neuropeptide G protein-coupled receptor. It has been identified in all sequenced bee genomes from the solitary to the eusocial. In the current study, we try to clarify the transitions of AKHR on lipid utilization and other potential functions from solitary to eusocial bees. The results showed that the AKHRs were divided into different groups based on their social complexity approximately. Nevertheless, the critical motifs and tertiary structures were highly conserved. As to the post-translational modifications, the eusocial possessed more phosphorylation residues and modification patterns, which might be due to the necessity of more diverse functions. These results suggest that AKHRs are highly conserved on both primary motifs and tertiary structures, but more flexible on posttranslational modifications so as to accommodate to more complicated eusocial life
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