664 research outputs found
Fast simulation of the CEPC detector with Delphes
Fast simulation tools are highly appreciated in particle physics
phenomenology studies, especially in the exploration of the physics potential
of future experimental facilities. The Circular Electron Positron Collider is a
proposed Higgs and Z factory that can precisely measure the Higgs boson
properties and the electroweak precision observables. A fast-simulation toolkit
dedicated to the CEPC detector has been developed using Delphes. The comparison
shows that this fast simulation tool is highly consistent with the full
simulation, on a set of benchmark distributions. Therefore, we recommend this
fast simulation toolkit for CEPC phenomenological investigations
1,4-Bis[(2-ethyl-1H-benzimidazol-1-yl)methyl]benzene
In the title molecule, C26H26N4, the central benzene ring forms dihedral angles of 89.9 (2) and 85.4 (2)° with the two benzimidazole rings
catena-Poly[[[aquabis(4,4′-bipyridine-κN)zinc]-μ-l-tyrosinato-κ3 N,O 1:O 1′] nitrate dihydrate]
In the title compound, {[Zn(C9H10NO3)(C10H8N2)2(H2O)]NO3·2H2O}n, the ZnII atom is six-coordinated in a distorted octahedral geometry by two carboxylate O atoms and one amino N atom from two l-tyrosinate ligands, two N atoms from two 4,4′-bipyridine ligands, and one water molecule. Adjacent Zn atoms are bridged by the bidentate carboxylate groups into a cationic chain extending along [010]. N—H⋯N, O—H⋯N and O—H⋯O hydrogen bonds link the cationic chains, nitrate anions and uncoordinated water molecules into a supramolecular network. π–π interactions between the pyridine rings and between the pyridine and benzene rings [centroid–centroid distances = 3.615 (4) and 3.636 (4) Å] are present
Mars Atmospheric Entry Integrated Navigation with Partial Intermittent Measurements
Signal degradation suffered by the vehicle is a combination brownout and blackout during Mars atmospheric entry. The communications brownout means that signal fades and blackout means that the signal is lost completely. The communications brownout and blackout periods are analyzed and predicted with an altitude and velocity profiles. In the brownout period, the range measurements between the vehicle and the orbiters are modeled as intermittent measurements with the radio signal arrival probabilities, which are distributed as a Rayleigh distribution of the electron number density around the entry vehicle. A new integrated navigation strategy during the Mars atmospheric entry phase is proposed to consider the probabilities of the radio measurements in the communications brownout and blackout periods under the IMU/beacon scenario based on the information filter with intermittent measurements. Numerical navigation simulations are designed to show the performance of the proposed navigation strategy under the integrated navigation scenario
Exact algorithms to minimize interference in wireless sensor networks
AbstractFinding a low-interference connected topology is a fundamental problem in wireless sensor networks (WSNs). The problem of reducing interference through adjusting the nodes’ transmission radii in a connected network is one of the most well-known open algorithmic problems in wireless sensor network optimization. In this paper, we study minimization of the average interference and the maximum interference for the highway model, where all the nodes are arbitrarily distributed on a line. First, we prove that there is always an optimal topology with minimum interference that is planar. Then, two exact algorithms are proposed. The first one is an exact algorithm to minimize the average interference in polynomial time, O(n3Δ), where n is the number of nodes and Δ is the maximum node degree. The second one is an exact algorithm to minimize the maximum interference in sub-exponential time, O(n3ΔO(k)), where k=O(Δ) is the minimum maximum interference. All the optimal topologies constructed are planar
Impact of the Staphylococcus epidermidis LytSR two-component regulatory system on murein hydrolase activity, pyruvate utilization and global transcriptional profile
<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus epidermidis </it>has emerged as one of the most important nosocomial pathogens, mainly because of its ability to colonize implanted biomaterials by forming a biofilm. Extensive studies are focused on the molecular mechanisms involved in biofilm formation. The LytSR two-component regulatory system regulates autolysis and biofilm formation in <it>Staphylococcus aureus</it>. However, the role of LytSR played in <it>S. epidermidis </it>remained unknown.</p> <p>Results</p> <p>In the present study, we demonstrated that <it>lytSR </it>knock-out in <it>S. epidermidis </it>did not alter susceptibility to Triton X-100 induced autolysis. Quantitative murein hydrolase assay indicated that disruption of <it>lytSR </it>in <it>S. epidermidis </it>resulted in decreased activities of extracellular murein hydrolases, although zymogram showed no apparent differences in murein hydrolase patterns between <it>S. epidermidis </it>strain 1457 and its <it>lytSR </it>mutant. Compared to the wild-type counterpart, 1457<it>ΔlytSR</it> produced slightly more biofilm, with significantly decreased dead cells inside. Microarray analysis showed that <it>lytSR </it>mutation affected the transcription of 164 genes (123 genes were upregulated and 41 genes were downregulated). Specifically, genes encoding proteins responsible for protein synthesis, energy metabolism were downregulated, while genes involved in amino acid and nucleotide biosynthesis, amino acid transporters were upregulated. Impaired ability to utilize pyruvate and reduced activity of arginine deiminase was observed in 1457<it>ΔlytSR</it>, which is consistent with the microarray data.</p> <p>Conclusions</p> <p>The preliminary results suggest that in <it>S. epidermidis </it>LytSR two-component system regulates extracellular murein hydrolase activity, bacterial cell death and pyruvate utilization. Based on the microarray data, it appears that <it>lytSR </it>inactivation induces a stringent response. In addition, LytSR may indirectly enhance biofilm formation by altering the metabolic status of the bacteria.</p
Accelerated Sparse Recovery via Gradient Descent with Nonlinear Conjugate Gradient Momentum
This paper applies an idea of adaptive momentum for the nonlinear conjugate
gradient to accelerate optimization problems in sparse recovery. Specifically,
we consider two types of minimization problems: a (single) differentiable
function and the sum of a non-smooth function and a differentiable function. In
the first case, we adopt a fixed step size to avoid the traditional line search
and establish the convergence analysis of the proposed algorithm for a
quadratic problem. This acceleration is further incorporated with an operator
splitting technique to deal with the non-smooth function in the second case. We
use the convex and the nonconvex functionals as two
case studies to demonstrate the efficiency of the proposed approaches over
traditional methods
Animal personality can modulate sexual conflict over offspring provisioning
Sexual conflict over parental investment is widespread among species with biparental care. Studies have indicated that a high degree of behavioural similarity between the two parents can increase offspring survival; however, it remains unclear how sexual conflict over parental care is resolved. In this study, we examined whether similarity of personality traits between the two parents plays an important role in affecting the provisioning behaviour of each sex in a wild population of the chestnut thrush, Turdus rubrocanus. First, as expected, the mating pairs with more similar personality traits had higher provisioning rates than those pairs with dissimilar traits. Moreover, we found that the similarity of personality traits can modulate the sexual conflict over provisioning in this species, as both parents with more similar partners had relatively higher and less divergent provisioning rates. A partner removal experiment revealed how the sole female or male parent responded when the level of conflict over care increased (the removed partner does not provide any care). The majority of males always reduced their provisioning investment, while females’ decisions depended on the degree of similarity with their partners. Females compensated by provisioning more frequently in pairs of similar personality traits (i.e. accepting a high level of conflict), but reduced their provisioning investment in extremely dissimilar pairs. Our results promote a better understanding of the resolution of sexual conflict over provisioning and highlight the evolutionary significance of mating with similar partners based on certain personality traits
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