Tunable space-time crystal in room-temperature magnetodielectrics

We report the experimental realization of a space-time crystal with tunable periodicity in time and space in the magnon Bose-Einstein Condensate (BEC), formed in a room-temperature Yttrium Iron Garnet (YIG) film by radio-frequency space-homogeneous magnetic field. The magnon BEC is prepared to have a well defined frequency and non-zero wavevector. We demonstrate how the crystalline "density" as well as the time and space textures of the resulting crystal may be tuned by varying the experimental parameters: external static magnetic field, temperature, thickness of the YIG film and power of the radio-frequency field. The proposed space-time crystals provide a new dimension for exploring dynamical phases of matter and can serve as a model nonlinear Floquet system, that brings in touch the rich fields of classical nonlinear waves, magnonics and periodically driven systems

Long-distance supercurrent transport in a room-temperature Bose-Einstein magnon condensate

The term supercurrent relates to a macroscopic dissipation-free collective motion of a quantum condensate and is commonly associated with such famous low-temperature phenomena as superconductivity and superfluidity. Another type of motion of quantum condensates is second sound - a wave of the density of a condensate. Recently, we reported on an enhanced decay of a parametrically induced Bose-Einstein condensate (BEC) of magnons caused by a supercurrent outflow of the BEC phase from the locally heated area of a room temperature magnetic film. Here, we present the direct experimental observation of a long-distance spin transport in such a system. The condensed magnons being pushed out from the potential well within the heated area form a density wave, which propagates through the BEC many hundreds of micrometers in the form of a specific second sound pulse - Bogoliubov waves - and is reflected from the sample edge. The discovery of the long distance supercurrent transport in the magnon BEC further advances the frontier of the physics of quasiparticles and allows for the application of related transport phenomena for low-loss data transfer in perspective magnon spintronics devices

The need for sustainability, equity, and international exchange: perspectives of early career environmental psychologists on the future of conferences

At the 2019 and 2021 International Conference on Environmental Psychology, discussions were held on the future of conferences in light of the enormous greenhouse gas emissions and inequities associated with conference travel. In this manuscript, we provide an early career researcher (ECR) perspective on this discussion. We argue that travel-intensive conference practices damage both the environment and our credibility as a discipline, conflict with the intrinsic values and motivations of our discipline, and are inequitable. As such, they must change. This change can be achieved by moving toward virtual and hybrid conferences, which can reduce researchers’ carbon footprints and promote equity, if employed carefully and with informal exchange as a priority. By acting collectively and with the support of institutional change, we can adapt conference travel norms in our field. To investigate whether our arguments correspond to views in the wider community of ECRs within environmental psychology, we conducted a community case study. By leveraging our professional networks and directly contacting researchers in countries underrepresented in those networks, we recruited 117 ECRs in 32 countries for an online survey in February 2022. The surveyed ECRs supported a change in conference travel practices, including flying less, and perceived the number of researchers wanting to reduce their travel emissions to be growing. Thirteen percent of respondents had even considered leaving academia due to travel requirements. Concerning alternative conference formats, a mixed picture emerged. Overall, participants had slightly negative evaluations of virtual conferences, but expected them to improve within the next 5 years. However, ECRs with health issues, facing visa challenges, on low funding, living in remote areas, with caretaking obligations or facing travel restrictions due to COVID-19 expected a switch toward virtual or hybrid conferences to positively affect their groups. Participants were divided about their ability to build professional relationships in virtual settings, but believed that maintaining relationships virtually is possible. We conclude by arguing that the concerns of ECRs in environmental psychology about current and alternative conference practices must be taken seriously. We call on our community to work on collective solutions and less travel-intensive conference designs using participatory methods. Copyright © 2022 Köhler, Kreil, Wenger, Darmandieu, Graves, Haugestad, Holzen, Keller, Lloyd, Marczak, Medugorac and Rosa

Experimental observation of Josephson oscillations in a room-temperature Bose-Einstein magnon condensate

The alternating current (ac) Josephson effect in a time-independent spatially-inhomogeneous setting is manifested by the occurrence of Josephson oscillations - periodic macroscopic phase-induced collective motions of the quantum condensate. So far, this phenomenon was observed at cryogenic temperatures in superconductors, in superfluid helium, and in Bose-Einstein condensates (BECs) of trapped atoms. Here, we report on the discovery of the ac Josephson effect in a magnon BEC carried by a room-temperature ferrimagnetic film. The BEC is formed in a parametrically populated magnon gas in the spatial vicinity of a magnetic trench created by a dc electric current. The appearance of the Josephson effect is manifested by oscillations of the magnon BEC density in the trench, caused by a coherent phase shift between this BEC and the BEC in the nearby regions. Our findings advance the physics of room-temperature macroscopic quantum phenomena and will allow for their application for data processing in magnon spintronics devices

Electroexcitation of the Roper resonance from CLAS data

The helicity amplitudes of the electroexcitation of the Roper resonance on proton are extracted at 1.7 < Q2 < 4.2 GeV2 from recent high precision JLab-CLAS cross sections data and longitudinally polarized beam asymmetry for pi+ electroproduction on protons. The analysis is made using two approaches, dispersion relations and unitary isobar model, which give consistent results. It is found that the transverse helicity amplitude for the gamma* p --> P11(1440) transition, which is large and negative at Q2=0, becomes large and positive at Q2 ~ 2 GeV2, and then drops slowly with Q2. Longitudinal helicity amplitude, that was previously found from CLAS data as large and positive at Q2=0.4,0.65 GeV2, drops with Q2. These results rule out the presentation of P11(1440) as a 3qG hybrid state, and provide strong evidence in favor of this resonance as a first radial excitation of the 3q ground state.Comment: 3 pages, 2 figures, Talk on the Workshop on "The Physics of Excited Nucleons", Bonn, Germany, October 200

Genomic and transcriptional analysis of protein heterogeneity of the honeybee venom allergen Api m 6

Several components of honeybee venom are known to cause allergenic responses in humans and other vertebrates. One such component, the minor allergen Api m 6, has been known to show amino acid variation but the genetic mechanism for this variation is unknown. Here we show that Api m 6 is derived from a single locus, and that substantial protein-level variation has a simple genome-level cause, without the need to invoke multiple loci or alternatively spliced exons. Api m 6 sits near a misassembled section of the honeybee genome sequence, and we propose that a substantial number of indels at and near Api m 6 might be the root cause of this misassembly. We suggest that genes such as Api m 6 with coding-region or untranslated region indels might have had a strong effect on the assembly of this draft of the honeybee genome

Transport of Proteins into Mitochondria

The mitochondrial ADP/ATP carrier is an integral transmembrane protein of the inner membrane. It is synthesized on cytoplasmic ribosomes. Kinetic data suggested that this protein is transferred into mitochondria in a posttranslational manner. The following results provide further evidence for such a mechanism and provide information on its details. 1. In homologous and heterologous translation systems the newly synthesized ADP/ATP carrier protein is present in the postribosomal supernatant. 2. Analysis by density gradient centrifugation and gel filtration shows, that the ADP/ATP carrier molecules in the postribosomal fraction are present as soluble complexes with apparent molecular weights of about 120000 and 500000 or larger. The carrier binds detergents such as Triton X-100 and deoxycholate forming mixed micelles with molecular weights of about 200000–400000. 3. Incubation of a postribosomal supernatant of a reticulocyte lysate containing newly synthesized ADP/ATP carrier with mitochondria isolated from Neurospora spheroplasts results in efficient transfer of the carrier into mitochondria. About 20–30% of the transferred carrier are resistant to proteinase in whole mitochondria. The authentic mature protein is also largely resistant to proteinase in whole mitochondria and sensitive after lysis of mitochondria with detergent. Integrity of mitochondria is a prerequisite for translocation into proteinase resistant position. 4. The transfer in vitro into a proteinase-resistant form is inhibited by the uncoupler carbonyl-cyanide m-chlorophenylhydrazone but not the proteinase-sensitive binding. These observations suggest that the posttranslational transfer of ADP/ATP carrier occurs via the cytosolic space through a soluble oligomeric precursor form. This precursor is taken up by intact mitochondria into an integral position in the membrane. These findings are considered to be of general importance for the intracellular transfer of insoluble membrane proteins. They support the view that such proteins can exist in a water-soluble form its precursors and upon integration into the membrane undergo a conformational change. Uptake into the membrane may involve the cleavage of an additional sequence in some proteins, but this appears not to be a prerequisite as demonstrated by the ADP/ATP carrier protein

Stratification of co-evolving genomic groups using ranked phylogenetic profiles

<p>Abstract</p> <p>Background</p> <p>Previous methods of detecting the taxonomic origins of arbitrary sequence collections, with a significant impact to genome analysis and in particular metagenomics, have primarily focused on compositional features of genomes. The evolutionary patterns of phylogenetic distribution of genes or proteins, represented by phylogenetic profiles, provide an alternative approach for the detection of taxonomic origins, but typically suffer from low accuracy. Herein, we present <it>rank-BLAST</it>, a novel approach for the assignment of protein sequences into genomic groups of the same taxonomic origin, based on the ranking order of phylogenetic profiles of target genes or proteins across the reference database.</p> <p>Results</p> <p>The rank-BLAST approach is validated by computing the phylogenetic profiles of all sequences for five distinct microbial species of varying degrees of phylogenetic proximity, against a reference database of 243 fully sequenced genomes. The approach - a combination of sequence searches, statistical estimation and clustering - analyses the degree of sequence divergence between sets of protein sequences and allows the classification of protein sequences according to the species of origin with high accuracy, allowing taxonomic classification of 64% of the proteins studied. In most cases, a main cluster is detected, representing the corresponding species. Secondary, functionally distinct and species-specific clusters exhibit different patterns of phylogenetic distribution, thus flagging gene groups of interest. Detailed analyses of such cases are provided as examples.</p> <p>Conclusion</p> <p>Our results indicate that the rank-BLAST approach can capture the taxonomic origins of sequence collections in an accurate and efficient manner. The approach can be useful both for the analysis of genome evolution and the detection of species groups in metagenomics samples.</p