Radiative corrections and Lorentz violation Ferrari, A. F.; Nascimento, J. R.; Petrov, A. Yu
European physical journal. C, Particles and fields,
05/2020, Volume:
80, Issue:
5
Journal Article
Peer reviewed
Open access
Radiative corrections in Lorentz violating (LV) models have already received a lot of attention in the literature in recent years, with many instances where a LV operator in one sector of the ...Standard Model Extension (SME) generates, via loop corrections, one of the LV coefficients in the photon sector, which is probably the most understood and well constrained part of the SME. In many of these works, however, the now standard notation of the SME is not used, which can obscure the comparison of different results, and their possible phenomenological relevance. In this work, we fill this gap, trying to build up a more general perspective on the topic, bringing many of the results to the SME conventional notation and commenting on their possible phenomenological relevance. We uncover one example where a result already presented in the literature can be used to place a stronger bound on the temporal component of the
b
μ
coefficient of the fermion sector of the SME.
This paper reports a review of an environmentally clean and efficient source of energy such as solid oxide fuel cell hybrid systems. Due to climate concerns, most nations are seeking alternative ...means of generating energy from a clean, efficient and environmental-friendly method. However, this has proven a big hurdle for both academic and industry researchers over many years. Currently, practical and technically feasible solution can be obtained via an integration of a microturbine and a fuel cell (hybrid systems). Combining the two distinct systems in a hybrid arrangement the efficiency of the microturbine increases from 25 to 30% to the 60–65% range. Hence, this paper outlines an engineering power generation solution towards the acute global population growth, the growing need, environmental concerns, intelligent use of energy with attendant environmental and hybrid system layouts concerning arising problems and tentative proposed solutions. Furthermore, advantages of a solid oxide fuel cell hybrid systems with respect to the other technologies are identified and discussed rationally. Special attention is devoted to modelling with software and emulator rigs and system prototypes. The paper also reviews the limitations and the benefits of these hybrid systems in relationship with energy, environment and sustainable development. Few potential applications, as long-term potential actions for sustainable development, and the future of such devices are further discussed.
•Environmentally clean and efficient source of energy.•Integration of a microturbine and a fuel cell (hybrid systems).•Fuel cell modelling and SOFC hybrid cycles.•Limitations and the benefits of these hybrid systems in relationship with energy, environment and sustainable development.•Few potential applications, as long-term potential actions for sustainable development, and the future of such devices.
This paper is dedicated to the study of interactions between external sources for the electromagnetic field in the presence of Lorentz symmetry breaking. We focus on a higher derivative, Lorentz ...violating interaction that arises from a specific model that was argued to lead to interesting effects in the low energy phenomenology of light pseudoscalars interacting with photons. The kind of higher derivative Lorentz violating interaction we discuss are called nonminimal. They are usually expected to be relevant only at very high energies, but we argue they might also induce relevant effects in low energy phenomena. Indeed, we show that the Lorentz violating background considered by us leads to several phenomena that have no counterpart in Maxwell theory, such as nontrivial torques on isolated electric dipoles, as well as nontrivial forces and torques between line currents and point like charges, as well as among Dirac strings and other electromagnetic sources.
Romosozumab binds sclerostin, increases bone formation, and decreases bone resorption. Postmenopausal women with osteoporosis were assigned to romosozumab or placebo for 1 year, followed by 1 year of ...denosumab. Romosozumab was associated with lower vertebral and clinical fracture risk.
Osteoporosis can lead to fragility fractures, which result in clinical burden and increased mortality.
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,
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Even after a fracture, fewer than 25% of patients receive pharmacologic treatment for osteoporosis.
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–
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After the discovery that sclerostin deficiency causes rare genetic conditions that are characterized by high bone mass and resistance to fracture,
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,
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sclerostin became a therapeutic target for the treatment of osteoporosis. Sclerostin, a negative regulator of bone formation that is secreted by osteocytes,
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inhibits Wnt signaling, down-regulating this stimulus for osteoblast development and function.
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Romosozumab (Amgen and UCB Pharma) is a monoclonal antibody that binds and inhibits sclerostin, with . . .
Bursting neurons fire rapid sequences of action potential spikes followed by a quiescent period. The basic dynamical mechanism of bursting is the slow currents that modulate a fast spiking activity ...caused by rapid ionic currents. Minimal models of bursting neurons must include both effects. We considered one of these models and its relation with a generalized Kuramoto model, thanks to the definition of a geometrical phase for bursting and a corresponding frequency. We considered neuronal networks with different connection topologies and investigated the transition from a non-synchronized to a partially phase-synchronized state as the coupling strength is varied. The numerically determined critical coupling strength value for this transition to occur is compared with theoretical results valid for the generalized Kuramoto model.
Crohn's disease (CD) is characterized by chronic inflammation of the human intestine. Several studies have demonstrated that the intestinal mucosa of CD patients in Western countries is abnormally ...colonized by adherent-invasive Escherichia coli (AIEC) strains. However, no studies to date have focused on the involvement of such E. coli strains in CD patients in Brazil. Here, we characterized E. coli strains associated with the ileal mucosa of Brazilian CD patients (ileal biopsies from 35 subjects, 24 CD patients and 11 controls). The colonization level of adherent Enterobacteriaceae associated with the ileal mucosa of CD patients was significantly higher than that of the controls. The proportions of E. coli strains belonging to phylogroups B1 and B2 were two-fold higher in strains isolated from CD patients than in those isolated from controls. CD patients in the active phase harbored 10-fold more E. coli belonging to group B2 than CD patients in remission. Only a few E. coli isolates had invasive properties and the ability to survive within macrophages, but 25% of CD patients in Brazil (6/24) harbored at least one E. coli strain belonging to the AIEC pathobiont. However, fimH sequence analysis showed only a few polymorphisms in the FimH adhesin of strains isolated in this study compared to the FimH adhesin of AIEC collections isolated from European patients. Mucosa-associated E. coli strains colonize the intestinal mucosa of Brazilian CD patients. However, the strains isolated from Brazilian CD patients have probably not yet co-evolved with their hosts and therefore have not fully developed a strong adherent-invasive phenotype. Thus, it will be crucial to follow in the future the emergence and evolution of AIEC pathobionts in the Brazilian population.
•Plant optimization for hydrogen generation from renewable sources.•Experimental tests on a 42kW alkaline electrolyser.•Time-dependent hierarchical thermo-economic optimization.•Italian case for ...electricity costs and solar irradiation (Savona).
In this paper an approach for the determination of the optimal size and management of a plant for hydrogen production from renewable source (photovoltaic panels) is presented.
Hydrogen is produced by a pressurized alkaline electrolyser (42kW) installed at the University Campus of Savona (Italy) in 2014 and fed by electrical energy produced by photovoltaic panels. Experimental tests have been carried out in order to analyze the performance curve of the electrolyser in different operative conditions, investigating the influence of the different parameters on the efficiency. The results have been implemented in a software tool in order to describe the behavior of the systems in off-design conditions.
Since the electrical energy produced by photovoltaic panels and used to feed the electrolyser is strongly variable because of the random nature of the solar irradiance, a time-dependent hierarchical thermo-economic analysis is carried out to evaluate both the optimal size and the management approach related to the system, considering a fixed size of 1MW for the photovoltaic panels. The thermo-economic analysis is performed with the software tool W-ECoMP, developed by the authors’ research group: the Italian energy scenario is considered, investigating the impact of electricity cost on the results as well.
Kinesin-1 is responsible for microtubule-based transport of numerous cellular cargoes. Here, we explored the regulation of kinesin-1 by MAP7 proteins. We found that all four mammalian MAP7 family ...members bind to kinesin-1. In HeLa cells, MAP7, MAP7D1, and MAP7D3 act redundantly to enable kinesin-1-dependent transport and microtubule recruitment of the truncated kinesin-1 KIF5B-560, which contains the stalk but not the cargo-binding and autoregulatory regions. In vitro, purified MAP7 and MAP7D3 increase microtubule landing rate and processivity of kinesin-1 through transient association with the motor. MAP7 proteins promote binding of kinesin-1 to microtubules both directly, through the N-terminal microtubule-binding domain and unstructured linker region, and indirectly, through an allosteric effect exerted by the kinesin-binding C-terminal domain. Compared with MAP7, MAP7D3 has a higher affinity for kinesin-1 and a lower affinity for microtubules and, unlike MAP7, can be cotransported with the motor. We propose that MAP7 proteins are microtubule-tethered kinesin-1 activators, with which the motor transiently interacts as it moves along microtubules.
Abstract
Context
Limited information is available concerning the genetic spectrum of pheochromocytoma and paraganglioma (PPGL) patients in South America. Germline SDHB large deletions are very rare ...worldwide, but most of the individuals harboring the SDHB exon 1 deletion originated from the Iberian Peninsula.
Objective
Our aim was to investigate the spectrum of SDHB genetic defects in a large cohort of Brazilian patients with PPGLs.
Methods
Genetic investigation of 155 index PPGL patients was performed by Sanger DNA sequencing, multiplex ligation-dependent probe amplification, and/or target next-generation sequencing panel. Common ancestrality was investigated by microsatellite genotyping with haplotype reconstruction, and analysis of deletion breakpoint.
Results
Among 155 index patients, heterozygous germline SDHB pathogenic or likely pathogenic variants were identified in 22 cases (14.2%). The heterozygous SDHB exon 1 complete deletion was the most frequent genetic defect in SDHB, identified in 8 out of 22 (36%) of patients. Haplotype analysis of 5 SDHB flanking microsatellite markers demonstrated a significant difference in haplotype frequencies in a case-control permutation test (P = 0.03). More precisely, 3 closer/informative microsatellites were shared by 6 out of 8 apparently unrelated cases (75%) (SDHB-GATA29A05-D1S2826-D1S2644 | SDHB-186-130-213), which was observed in only 1 chromosome (1/42) without SDHB exon 1 deletion (X2 = 29.43; P < 0.001). Moreover, all cases with SDHB exon 1 deletion had the same gene breakpoint pattern of a 15 678 bp deletion previously described in the Iberian Peninsula, indicating a common origin.
Conclusion
The germline heterozygous SDHB exon 1 deletion was the most frequent genetic defect in the Brazilian PPGL cohort. Our findings demonstrated a founder effect for the SDHB exon 1 deletion in Brazilian patients with paragangliomas.
In this paper we consider classical effects in a model for a scalar field incorporating Lorentz symmetry breaking due to the presence of a single background vector vμ coupled to its derivative. We ...investigate of the interaction energy between stationary steady sources concentrated along parallel branes with an arbitrary number of dimensions, and derive from this study some physical consequences. For the case of the scalar dipole we show the emergence of a nontrivial torque, which is a distinctive sign of the Lorentz violation. We also investigate a similar model in the presence of a semi-transparent mirror. For a general relative orientation between the mirror and the vμ, we are able to perform calculations perturbatively in vμ up to second order, and we also present exact results specific cases. For all these configurations, the propagator for the scalar field and the interaction force between the mirror and a point-like field source are computed. It is shown that the image method is valid in our model for the Dirichlet's boundary condition, and we argue that this is a non-trivial result. We also show the emergence of a torque on the mirror depending on its orientation with respect to the Lorentz violating background: this is a new effect with no counterpart in theories with Lorentz symmetry in the presence of mirrors.
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