A no-pure-boost uncertainty principle from spacetime noncommutativity

We study boost and space-rotation transformations in kappa-Minkowski noncommutative spacetime, using the techniques that some of us had previously developed (hep-th/0607221) for a description of translations in kappa-Minkowski, which in particular led to the introduction of translation transformation parameters that do not commute with the spacetime coordinates. We find a similar description of boosts and space rotations, which allows us to identify some associated conserved charges, but the form of the commutators between transformation parameters and spacetime coordinates is incompatible with the possibility of a pure boost.Comment: 8 pages, LaTe

Three-dimensional separation in shock/boundary layer interaction

A Large-eddy simulation of a shock impinging on a turbulent boundary layer is carried out and demonstrates good agreement with the experiments. A special emphasis is put on the analysis of the three-dimensional modulation of the flow in order to clarify the origin of the mean vortices located in the separation region highlighted by the experimen

Berry Phase Effects in the dynamics of Dirac Electrons in Doubly Special Relativity Framework

We consider the Doubly Special Relativity (DSR) generalization of Dirac equation in an external potential in the Magueijo-Smolin base. The particles obey a modified energy-momentum dispersion relation. The semiclassical diagonalization of the Dirac Hamiltonian reveals the intrinsic Berry phase effects in the particle dynamics

Automatic activies of the spinal cord concerned with the respiratory movements

1. After spinal transection at the medulla-spinal junction the thoracic respiratory movements no longer appear in the adult animals, nevertheless the sporadic spike discharges can be recorded from the intercostal muscles. 2. Both in the acute and chronic experiments the spinal cord is transected at the two levels of Th7 and Thl1 respectively and all the dorsal rootlets coming into that part of the cord lying between the transections are severed. The sporadic spike discharges with irregular intervals varying about 0.5 to 3.0 sec. can be recorded from intercostal muscles in the 8th to 10th segments of the spinal cord isolated. There can never be found any reflex influence of the skin stimulation upon the discharges, which also disappear provided the intercostal nerves innervating the muscles are severed. 3. From these results it may be concluded that the spinal cord is endowed with an ability to initiate the impulses autochthonously to excite the intercostal muscles, even though it is only poorly developed in the adult animals.</p

Interference effects in two-photon ATI by multiple orders high harmonics with random or locked phases

We numerically study 2-photon processes using a set of harmonics from a Ti:Sapphire laser and in particular interference effects in the Above Threshold Ionization spectra. We compare the situation where the harmonic phases are assumed locked to the case where they have a random distribution. Suggestions for possible experiments, using realistic parameters are discussed.Comment: 11 pages, 13 figures, LaTe

Disentangling Spectral Phases of Interfering Autoionizing States from Attosecond Interferometric Measurements

We have determined spectral phases of Ne autoionizing states from extreme ultraviolet and midinfrared attosecond interferometric measurements and ab initio full-electron time-dependent theoretical calculations in an energy interval where several of these states are coherently populated. The retrieved phases exhibit a complex behavior as a function of photon energy, which is the consequence of the interference between paths involving various resonances. In spite of this complexity, we show that phases for individual resonances can still be obtained from experiment by using an extension of the Fano model of atomic resonances. As simultaneous excitation of several resonances is a common scenario in many-electron systems, the present work paves the way to reconstruct electron wave packets coherently generated by attosecond pulses in systems larger than heliumWork supported by the ERC proof-of-concept Grant No. 780284-Imaging-XChem within the seventh framework program of the European Union, the MINECO Project No. FIS2013-42002-R, the EU-H2020- LASERLABEUROPE-654148, the ANR Projects No. ANR-15-CE30-0001-CIMBAAD, No. ANR-11- EQPX0005-ATTOLAB, and No. ANR-10-LABX-0039- PALM, the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award no. DEGF02-04ER15614, and the NSF Grant No. PHY-1607588. Calculations were performed at CCC-UAM and Marenostrum Supercomputer Center. F. M. acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant No. SEV-2016- 0686) and the “María de Maeztu” Programme for Units of Excellence in R&D (Grant No. MDM-2014-0377

The Tara Pacific expedition—A pan-ecosystemic approach of the “-omics” complexity of coral reef holobionts across the Pacific Ocean

Coral reefs are the most diverse habitats in the marine realm. Their productivity, structural complexity, and biodiversity critically depend on ecosystem services provided by corals that are threatened because of climate change effects—in particular, ocean warming and acidification. The coral holobiont is composed of the coral animal host, endosymbiotic dinoflagellates, associated viruses, bacteria, and other microeukaryotes. In particular, the mandatory photosymbiosis with microalgae of the family Symbiodiniaceae and its consequences on the evolution, physiology, and stress resilience of the coral holobiont have yet to be fully elucidated. The functioning of the holobiont as a whole is largely unknown, although bacteria and viruses are presumed to play roles in metabolic interactions, immunity, and stress tolerance. In the context of climate change and anthropogenic threats on coral reef ecosystems, the Tara Pacific project aims to provide a baseline of the “-omics” complexity of the coral holobiont and its ecosystem across the Pacific Ocean and for various oceanographically distinct defined areas. Inspired by the previous Tara Oceans expeditions, the Tara Pacific expedition (2016–2018) has applied a pan-ecosystemic approach on coral reefs throughout the Pacific Ocean, drawing an east–west transect from Panama to Papua New Guinea and a south–north transect from Australia to Japan, sampling corals throughout 32 island systems with local replicates. Tara Pacific has developed and applied state-of-the-art technologies in very-high-throughput genetic sequencing and molecular analysis to reveal the entire microbial and chemical diversity as well as functional traits associated with coral holobionts, together with various measures on environmental forcing. This ambitious project aims at revealing a massive amount of novel biodiversity, shedding light on the complex links between genomes, transcriptomes, metabolomes, organisms, and ecosystem functions in coral reefs and providing a reference of the biological state of modern coral reefs in the Anthropocene

The CBD Post‐2020 biodiversity framework: People's place within the rest of nature

Recognizing two decades of failure to achieve global goals and targets, parties to the Convention on Biological Diversity are in the final phase of negotiating a Post-2020 Global Biodiversity Framework for the conservation, sustainable use and benefit sharing of biodiversity. The framework attempts to set out pathways, goals and targets for the next decade to achieve positive biodiversity change. This perspective intends to help that framework set people firmly as part of nature, not apart from it. Despite work done so far through four meetings, new thinking and focus is still needed on ‘what’ changes must be conceptualized and implemented, and ‘how’ those changes are to be delivered. To help achieve that new thinking, as a broad range of people, many with a focus on aquatic systems, we highlight six key foci that offer potential to strengthen delivery of the framework and break the ‘business as usual’ logjam. These foci are as follows: (i) a reframing of the narrative of ‘people's relationship with the rest of nature’ and emphasize the crucial role of Indigenous Peoples and Local Communities in delivering positive biodiversity change; (ii) moving beyond a focus on species and places by prioritizing ecosystem function and resilience; (iii) supporting a diversity of top-down and bottom-up governance processes; (iv) embracing new technologies to make and measure progress; (v) linking business more effectively with biodiversity and (vi) leveraging the power of international agencies and programmes. Given they are linked to a greater or lesser degree, implementing these six foci together will lead to a much-needed broadening of the framework, especially those of business and broader urban civil society, as well as those of Indigenous Peoples and Local Communities. Read the free Plain Language Summary for this article on the Journal blog