Short Spikes Research Articles

The Thermal Emission in Short Gamma-Ray Bursts with Extended Emission Observed by Fermi/GBM

Short gamma-ray bursts (SGRBs) with extended emission (EE) are composed of initial main emission (ME) with a short hard spike, followed by a long-lasting EE. Whether the ME and EE originated from the same origin or not, as well as the jet composition, remains an open question. In this paper, we present a systematic analysis of 36 gamma-ray bursts (GRBs) in our sample, which are identified as the category of SGRBs with EE as observed by Fermi/Gamma-ray Burst Monitor. By extracting time-integrated spectra of ME and EE with cutoff power-law or Band models for our sample, we find that 20 out of 36 SGRBs have α values that exceed the death line (e.g., −2/3) of synchrotron emission within either ME or EE phases, and we suggest that the quasi-thermal component should exist in the prompt emission. Then, we extract the time-resolved spectra of our samples, but only four GRBs are bright enough to extract the time-resolved spectra. We find that both thermal and nonthermal emissions do exist in the prompt emission of those four bright GRBs, which suggests that a hybrid jet (e.g., matter and Poynting-flux outflow) in GRBs should exist. Moreover, strong positive correlations (e.g., F tot–Γ and F tot–kT) in the time-resolved spectra of ME and EE for those four GRBs have been discovered. This indicates that the spectral evolution of both ME and EE seem to share similar behavior, possibly from the same physical origin.

Reshaping and enzymatic activity may allow viruses to move through the mucus.

Filamentous viruses like influenza and torovirus often display systematic bends and arcs of mysterious physical origin. We propose that such viruses undergo an instability from a cylindrically symmetric to a toroidally curved state. This "toro-elastic" state emerges via spontaneous symmetry breaking under prestress due to short range spike protein interactions magnified by surface topography. Once surface stresses are sufficiently large, the filament buckles and the curved state constitutes a soft mode that can potentially propagate through the filament's material frame around a Mexican-hat-type potential. In the mucus of our airways, which constitutes a soft, porous 3D network, glycan chains are omnipresent and influenza's spike proteins are known to efficiently bind and cut them. We next show that such a non-equilibrium enzymatic reaction can induce spontaneous rotation of the curved state, leading to a whole body reshaping propulsion similar to - but different from - eukaryotic flagella and spirochetes.

Antiaris africana aqueous extract inhibits chronic demyelination and seizures in mice

Demyelinating diseases are commonly associated with epileptic seizures and have limited management options. Hence, the need to investigate potential options for management of such seizures. Antiaris Africana extract (AE) was investigated for effect in chronic demyelinating seizures. Cuprizone treatment induced short but frequent spike discharges in mice. Antiaris Africana extract (300 mg/kg) treatment abolished epileptiform discharges. Cuprizone administration caused severe demyelination in the corpus callosum. After the demyelination phase, myelin content decreased to 22.86 ± 1.92 % in the cuprizone-only group. However, there was an increase to 52.14 ± 3.91 % in cuprizone-only group and 62.00 ± 2.78 % in the Antiaris africana extract group respectively, after a 4-week cuprizone cessation period. Treatment with AE and LEV visibly altered myelin growth. Antiaris africana extract treatment produced significant (P < 0.001, F (3, 16) = 698.4) increase in locomotor activity similar to LEV (P < 0.001,F (2, 12) = 678.7) and DZP (P < 0.001, F (2, 12) = 620.4) and improved beam traversal time (18.71 ± 2.244 s; 95 % CI: 13.22–24.20) while causing significantly (P < 0.05, F (2, 15) = 6.667) fewer stepping errors. Antiaris africana extract inhibits seizures induced by chronic demyelination and has beneficial effects on motor coordination.

Fine mapping of two recessive genes TaFLA1 and TaSPL8 controlling flag leaf angle in bread wheat

Flag leaf angle is one of the key target traits in high yield wheat breeding. A smaller flag leaf angle reduces shading and enables plants to grow at a higher density, which increases yield. Here we identified a mutant, je0407, with an 84.34%–89.35% smaller flag leaf angle compared with the wild type. The mutant also had an abnormal lamina joint and no ligule or auricle. Genetic analysis indicated that the ligule was controlled by two recessive genes, which were mapped to chromosomes 2AS and 2DL. The mutant allele on chromosome 2AS was named Tafla1b, and it was fine mapped to a 1 Mb physical interval. The mutant allele on chr. 2DL was identified as Taspl8b, a novel allele of TaSPL8 with a missense mutation in the second exon, which was used to develop a cleaved amplified polymorphic sequence marker. F3 and F4 lines derived from crosses between Jing411 and je0407 were genotyped to investigate interactions between the Tafla1b and Taspl8b alleles. Plants with the Tafla1b/Taspl8a genotype had 58.41%–82.76% smaller flag leaf angles, 6.4%–24.9% shorter spikes, and a greater spikelet density (0.382 more spikelets per cm) compared with the wild type. Plants with the Tafla1a/Taspl8b genotype had 52.62%–82.24% smaller flag leaf angles and no differences in plant height or spikelet density compared with the wild type. Tafla1b/Taspl8b plants produced erect leaves with an abnormal lamina joint. The two alleles had dosage effects on ligule formation and flag leaf angle, but no significant effect on thousand-grain weight. The mutant alleles provide novel resources for improvement of wheat plant architecture.

Chloride hydrogeochemistry of the finger lakes in Central and Western New York, USA

Road deicing salts have impacted the hydrogeochemistry of lakes throughout the snow-belt region of the globe. This paper advances our understanding of the historical change in salt concentrations in, and sources to, the Finger Lakes of western and central New York state, and compares the results to other lakes across the globe. Surface water samples from Honeoye, Canandaigua, Keuka, Seneca, Cayuga, Owasco, Skaneateles and Otisco lakes were analyzed for chloride (Cl) concentrations, and augmented with published and unpublished decade, and for the first time, century-scale Cl data for these lakes and Hemlock Lake. A mass-balance model estimated the Cl flux required to match the measured Cl concentrations in each lake. Cl concentration and flux trends defined two groups of lakes. Group 1: A mid-1900′s peak in Cl concentrations was detected in Seneca and Cayuga lakes, that resulted from a short but significant spike of Cl, most likely from salt mine wastes during pre-Environmental Protection Agency times. Group 2: Hemlock, Honeoye, Canandaigua, Keuka, Owasco, Skaneateles and Otisco lakes, revealed smaller yet increasing concentrations and fluxes over time that were interpreted to reflect increasing use of road deicing salts in their watersheds and supported by correlations to their state and federal road lengths, percentage of impervious surfaces, water residence times in each watershed and the production of road salt in the US, but not to their trophic status, nor their percentage of agricultural land. Estimated Cl inputs from municipal wastewater treatment facilities, individual septic systems and the atmosphere (precipitation) were also insignificant in the Finger Lakes region. These results help clarify the processes responsible for increasing Chloride concentrations in lakes globally.

Enhanced Embedding of Cations into Titanium Surfaces by AC Plasma Electrolytic Oxidation for Osteointegrated Implants

Titanium and its alloys represent the gold standard for osteointegrated implants, but their characteristic bioinertness still hinders their optimal integration within the host tissues. This limitation can be overcome by introducing osteoinductive functionalities on their surface. Plasma electrolytic oxidation (PEO) has emerged as a cost‐effective and rapid electrochemical method for generating bioactive titanium dioxide (TiO2) coatings, but the incorporation of pro‐osteogenic cations with this technique is typically passive and, in turn, characterized by a low efficiency. Here, alternate current (AC) PEO is investigated as a flexible solution to incorporate zinc into TiO2 coatings by exploiting the active transport of cations during the cathodic phase of the process. The resulting microporous surfaces show a greater zinc incorporation and an increased presence of rutile domains compared to conventional direct current (DC) PEO coatings, without, however, yielding significant morphological differences. In vitro assays with human mesenchymal stem cells (hMSCs) reveal an increased metabolic activity of cells adhering onto AC PEO surfaces. In addition, the increased expression of osteogenic differentiation markers (RUNX2 and osteocalcin) indicates significant surface‐driven osteoinductive effects, particularly for coatings grown by applying a short cathodic spike. Taken together, these aspects make Zn‐doped AC PEO surfaces a promising solution for osteoinductive orthopedic and dental applications.

REVERSE INHIBITORY CONNECTIONS THROUGH GABA B-RECEPTORS SYNCHRONIZE INTERICTAL DISCHARGES IN THE CORTEX

Modern experimental data show that interictal discharges consist of a short spike and a slow wave, which is regarded as a prolonged hyperpolarization. On the model of interictal discharges synchronization, a study of reciprocal inhibitory connections was carried out. In rats in light narcotic sleep, after application of GABA A-receptor blockers to the cortex, interictal discharges occurred in neighboring cortical areas independently of each other, and then synchronization occurred. In the experiments in which the interictal discharges occurred simultaneously, the durations of the slow wave (inhibitory phase) were the same. During the registration in these and other experiments, there was an increase in the time delay between the moments of interictal discharges generation. Under conditions of increased synchronization, the duration of the slow wave (inhibitory phase) of interictal discharges increased. Interictal discharges, which occurred first, had a longer duration of inhibition compared to the duration in the neighboring point, because the inhibition from the neighboring networks via feedback inhibitory connections is added to its own inhibition in the neuronal network. When excitation occurred, it was followed by inhibition via feedback, which limited the period of excitation, and thus created a temporary integration window, and this also happened in the neighboring neural networks of the cortex.

Inheritance of fodder and seed productivity characteristics by F1 winter triticale hybrids

Purpose and Objectives. To characterize the inheritance of fodder and seed productivity characteristics by F1 winter triticale hybrids from reciprocal crossings. To select promising F1 combinations that show strong heterosis in three or more performance traits. Materials and Methods. The study was carried out at the Department of Fodder, Grain and Technical Crops Breeding of the Institute of Fodder and Agriculture of Podillia of NAAS in 2021 and 2022. The farming techniques were traditional for the forest-steppe. Parents and F1 were sown in a hybrid nursery using a manual marker; the interrow distance was was 30 cm; the interplant distance in the rows was 10 cm. Nine winter triticale varieties of different eco-geographical origins served as the starting material for direct and reverse crossings: Bozhych, Buzhanske, and Pavlodarskyi originating from Ukraine; Tornado, Khleborob, Soyuz, Sergiy, and Sibirskiy from Russia; and NTH 1933 from China. The heterosis degree was determined according to Matzinger et al. [15] and S. Fonseca, F. Patterson. Results and Discussion. Analysis of inheritance in F1 hybrids showed that the productive tillering capacity was inherited by different types, with negative overdominance (55%) and heterosis (20%) prevailing. Due to intra-allelic interactions of genes functioning in a heterozygous state only, selection of genotypes in early hybrid generations may be ineffective. However, there is a high probability of identification of transgressions of increased tillering in later hybrid generations. A combination with positive dominance, Khleborob / NTH 1933 (hp = 0.6; Ht = 3.3%; Hbt = -2.5%), is worth of special attention for selection of genotypes that would have increased tillering capacity. Combinations with negative overdominance (depression) are of little value in breeding for enhanced tillering. Our data on winter triticale demonstrated that the spike length inheritance by F1 hybrids had a wide spectrum: 10% of hybrid combinations showed positive overdominance (heterosis), 25% – positive dominance, 35% – intermediate inheritance, 15% – negative dominance, and 20% – negative overdominance (depression). This is attributed to different geographical and genetic origins of varieties selected for crossing. It should be noted that the Pavlodarskyi / Serhiy and Buzhanske / Pavlodarskyi hybrid combinations inherited spike length by depression. That is, it is possible to select winter triticale plants with relatively short spikes but with increased numbers of kernels among the distinguished hybrid combinations. Analysis in the Pavlodarskyi / Sergiy hybrid population proved that it was possible to select genotypes that would combine a relatively increased number of kernels per spike with an increased weight of kernels per spike. In the Sibirskiy / Pavlodarskyi, Tornado / Pavlodarskyi and Pavlodarskyi / Soyuz hybrid combinations with intermediate inheritance of the “kernel number per spike” trait, it was possible to select genotypes with small numbers of kernels, but kernels were heavier compared to those in the parental forms. The Bozhych / Pavlodarskyi and Sibirskiy / Pavlodarskyi hybrid combinations with positive dominance of the “kernel weight per plant” trait had intermediate inheritance of the “productive stem number” trait, the “spike length” trait and the “kernel number per spike” trait. Selection for increased weight of thousand kernels and, consequently, for increased weight of kernels per plant will be more effective in these combinations. It should be said that it is possible to generate genotypes with elongated spikes from these hybrid combinations. Negative dominance of the “productive stem number” trait, intermediate dominance of the “spike length” and “kernel number” traits, but little positive overdominance of the “kernel weight per spike” and the “kernel weight per plant” traits were intrinsic to the Pavlodarskyi / Soyuz hybrid combination. It is possible to identify genotypes with small numbers of productive stems and kernel numbers similar to those in a parent, but with an increased weight of thousand kernels. Conclusions. Analysis of the variability of the fodder and seed productivity traits in F1 winter triticale hybrids established that hybrid combinations differed significantly in terms of heterosis level and inheritance type. All possible variants of phenotypic dominance, from positive to negative overdominance, were identified. For such traits as the productive tillering, kernel weight per spike, kernel weight per plant, and dry matter weight per plant, depression was noted in most combinations (55–60%).

Chromosome number of &lt;i&gt;Carex brevispicula&lt;/i&gt; (Cyperaceae), a sedge endemic to Korea

&lt;i&gt;Carex brevispicula&lt;/i&gt; (Cyperaceae) is endemic to Korea and is characterized by constricted achenes, short lateral spikes, and awned staminate and pistillate scales. The species classified in sect. &lt;i&gt;Mitratae&lt;/i&gt; occurs throughout South Korea, perennating on mountains and/or rocky slopes under half shadow conditions. Meiotic chromosomes of the species were examined in this study, in which 33 meiotic cells from seven populations were found to be less than 2 μm long with non-constricted chromosomes (&lt;i&gt;n&lt;/i&gt; = 34&lt;sub&gt;II&lt;/sub&gt;). The stable chromosome number may be related to the narrow geographical distribution and/or distinct achene morphology. Further investigations of the distribution, morphological character variation, and chromosome characteristics should be conducted with closely related taxa to understand the derivation of the species and its endemism in Korea.

Characteristics of Synaptic Function of Mesoporous Silica-Titania and Mesoporous Titania Lateral Electrode Devices.

In this paper, we have fabricated non-volatile memory resistive switching (RS) devices and analyzed analog memristive characteristics using lateral electrodes with mesoporous silica-titania (meso-ST) and mesoporous titania (meso-T) layers. For the planar-type device having two parallel electrodes, current-voltage (I-V) curves and pulse-driven current changes could reveal successful long-term potentiation (LTP) along with long-term depression (LTD), respectively, by the RS active mesoporous two layers for 20~100 μm length. Through mechanism characterization using chemical analysis, non-filamental memristive behavior unlike the conventional metal electroforming was identified. Additionally, high performance of the synaptic operations could be also accomplished such that a high current of 10-6 Amp level could occur despite a wide electrode spacing and short pulse spike biases under ambient condition with moderate humidity (RH 30~50%). Moreover, it was confirmed that rectifying characteristics were observed during the I-V measurement, which was a representative feature of dual functionality of selection diode and the analog RS device for both meso-ST and meso-T devices. The memristive and synaptic functions along with the rectification property could facilitate a chance of potential implementation of the meso-ST and meso-T devices to neuromorphic electronics platform.

Structural Study of the Cobetia marina Bacteriophage 1 (Carin-1) by Cryo-EM.

Most of studied bacteriophages (phages) are terrestrial viruses. However, marine phages are shown to be highly involved in all levels of oceanic regulation. They are, however, still largely overlooked by the scientific community. By inducing cell lysis on half of the bacterial population daily, their role and influence on the bacterial biomass and evolution, as well as their impact in the global biogeochemical cycles, is undeniable. Cobetia marina virus 1 (Carin-1) is a member of the Podoviridae family infecting the γ-protoabacteria C. marina. Here, we present the almost complete, nearly-atomic resolution structure of Carin-1 comprising capsid, portal, and tail machineries at 3.5 Å, 3.8 Å and 3.9 Å, respectively, determined by cryo-electron microscopy (cryo-EM). Our experimental results, combined with AlphaFold2 (AF), allowed us to obtain the nearly-atomic structure of Carin-1 by fitting and refining the AF atomic models in the high resolution cryo-EM map, skipping the bottleneck of de-novo manual building and speeding up the structure determination process. Our structural results highlighted the T7-like nature of Carin1, as well as several novel structural features like the presence of short spikes on the capsid, reminiscent those described for Rhodobacter capsulatus gene transfer agent (RcGTA). This is, to our knowledge, the first time such assembly is described for a bacteriophage, shedding light into the common evolution and shared mechanisms between gene transfer agents and phages. This first full structure determined for a marine podophage allowed to propose an infection mechanism different than the one proposed for the archetypal podophage T7. IMPORTANCE Oceans play a central role in the carbon cycle on Earth and on the climate regulation (half of the planet's CO2 is absorbed by phytoplankton photosynthesis in the oceans and just as much O2 is liberated). The understanding of the biochemical equilibriums of marine biology represents a major goal for our future. By lysing half of the bacterial population every day, marine bacteriophages are key actors of these equilibriums. Despite their importance, these marine phages have, so far, only been studied a little and, in particular, structural insights are currently lacking, even though they are fundamental for the understanding of the molecular mechanisms of their mode of infection. The structures described in our manuscript allow us to propose an infection mechanism that differs from the one proposed for the terrestrial T7 virus, and might also allow us to, in the future, better understand the way bacteriophages shape the global ecosystem.

An artificial bridge circuit approach between two biological neurons using nanoscale topologies towards paralytic disorders

The advent of Nanoscale IC technology towards pulse-based neural systems reactivates the dead nervous about restoring the functionality of paralytic disorders. This work reports in first time a design of a novel CMOS biological neuron system, which replaces a dead neuron between two neurons to restore communication in paralyzed individuals. The work binds into three stages: design of a spiking leaky Integrator and Fire (LIF) neuron with refractory period mechanisms, which achieves a low power consumption of 2.4 μW, in the first stage; an adaptive homeostatic synapse with short and long-term spike plasticity, that reconfigure the spiking neuron networks of multichannel sensor electrodes to record the electric signal from the active cell as second stage; the final stage presents a low-power common source current reuse regulated cascode (CS-CR-RGC) TIA for amplifying the weak synapse current signal, which achieves a high gain of 135.71 dBΩ with an optimized noise performance of 0.19 pA/Hz. The entire work is designed and implemented using a CMOS 65 nm commercial process that occupies a die area of 400 μm × 120 μm.

Radial growth rate of near-critical crystal nuclei in poly(l-lactic acid) (PLLA) in Tammann's two-stage development method.

The specific features of crystal nucleation widely determine the morphology of the evolving crystalline material. Crystal nucleation is, as a rule, not accessible by direct observation of the nuclei, which develop with time. This limitation is caused by the small size (nanometer scale) of the critical nuclei and the stochastic nature of their formation. We describe an experimental approach to the determination of specific features of the cluster size distribution employing fast scanning calorimetry at scanning rates up to 10 000Ks-1. The surviving cluster fraction is determined by selectively melting/dissolving clusters smaller than the critical size corresponding to the highest temperature of a short spike positioned between the nucleation and the development stage in Tammann's two-stage method. This approach allows for estimating the time evolution of the radius of the largest detectable clusters in the distribution. Knowing this radius as a function of nucleation time allows for determining a radial growth rate. In the example of poly(l-lactic acid) (PLLA), the order of magnitude estimate of radial growth rates of clusters of about 2-5nm yields values between 10-5 and 10-3nms-1. The radial growth rate of micrometer-sized spherulites is available from optical microscopy. The corresponding values are about three orders of magnitude higher than the values for the nanometer-sized clusters. This difference is explainable by stochastic effects, transient features, and the size dependence of the growth processes on the nanometer scale. The experimental and (order of magnitude) classical nucleation theory estimates agree well.

Large-scale experiments on tsunami inundation and overtopping forces at vertical sea walls

Tsunami are very long gravity waves that may cause significant damage to coastal sea walls. The majority of relevant design codes and research papers that describe methods for predicting tsunami loads on coastal walls consider the scenario of transitory force from a bore-led wave. This does not relate to tsunami that do not form bore waves. Bore fronts generally cause short term spikes in force, which may have little effect on the vulnerability of massive structures. Post disaster accounts suggest that most coastal walls show damage that implies failure modes that occur over moderate to long durations. Therefore it is likely that the bore front assumption gives an overly conservative prediction of maximum force, and may not capture the full timescale of tsunami loading. This paper uses a pneumatic tsunami generation facility to determine the force loading on two vertical coastal sea walls during tsunami inundation. Two sea-wall models, 0.15 and 0.25 m high, with crown widths of 0.1 m (7.5 and 12.5 m at a nominal prototype scale of 1:50) are tested. It is shown that bore fronts only occur for short period waves over the bathymetry tested. Bore fronts cause a very short period spike in force, which is followed by a transitory force approximated by the hydrostatic pressure equation. The loading of tsunami length waves of periods ≥ 40 s (280 s prototype at 1:50 scale), which do not break is not greater than 1.2 times the hydrostatic force. Overtopping volume is positively correlated to the time duration of positive upstream head over the crest, rather than its maximum value. Overtopping causes a small increase in the horizontal load due to the addition of a drag and momentum load. The magnitude and time of these effects are small and short-lived in comparison to the hydrostatic load. The results compare well with available equations based on hydrostatic force and the engineer may apply a desired multiplying coefficient of a factor of at least 1.2 to account for any added pressure and momentum, and the factor of safety intended. • Tsunami loads on vertical walls are no greater than 1.2 times the theoretical hydrostatic load. • Only shorter wave periods break and form bores; longer tsunami-length waves do not break. • Tsunami overtopping volume is related to the duration of positive head over the crest. • Tsunami overtopping applies a relatively small (against the hydrostatic load) additional horizontal force.

AEROTHERMODYNAMICS OF COMBINED SPIKE AND COUNTERFLOW JET TECHNIQUE FOR REACTING HYPERSONIC FLOWS

Computational investigation is carried out to estimate the drag force and surface heating load for hypersonic reacting flows. An in-house viscous nonequilibrium finite volume-based reacting gas solver has been utilized. This solver is capable of investigating 11 chemical elementary reactions and temperature-dependent specific properties to reveal the effect of lower as well as higher freestream stagnation enthalpy conditions. Initially, the calorically perfect-gas and real-gas model-based simulations are carried out to understand the real-gas effects in the presence of a metallic spike. Computed surface pressure and heat flux are compared for the freestream stagnation enthalpy of 2 MJ/kg. The real-gas model predicts a 5&amp;#37; higher drag and 57.21 kW/m&lt;sup&gt;2&lt;/sup&gt; higher peak heat flux compared to the perfect-gas model. However, lower enthalpy conditions predict almost the same drag force for any spike length. Further, a counterflowing jet is installed at the root of the spike, and flow field alterations are studied for this proposed integrated configuration. The root jet further pushes the conical shock in the upstream direction and provides an extra-large recirculation zone. Here, the possibility of drag and surface heat flux reduction is very much evident due to the decrease in surface pressure and presence of low-temperature jet gas in the vicinity of the object. Various freestream stagnation enthalpies, as well as the jet pressures, are considered to investigate the performance alterations by the combination technique. It is observed that the drag and surface heat load reduction efficiency of the combined configuration decreases with an increase in the freestream stagnation enthalpy. Moreover, it increases when increasing the root jet pressure for given enthalpy conditions. Hence, instead of attaching a long spike at the stagnation region of a blunt-shaped object, the use of a short spike and low-pressure root jet is recommended for a better reduction in drag and surface heat load.

A kilonova following a long-duration gamma-ray burst at 350 Mpc.

Gamma-ray bursts (GRBs) are divided into two populations1,2; long GRBs that derive from the core collapse of massive stars (for example, ref. 3) and short GRBs that form in the merger of two compact objects4,5. Although it is common to divide the two populations at a gamma-ray duration of 2 s, classification based on duration does not always map to the progenitor. Notably, GRBs with short (≲2 s) spikes of prompt gamma-ray emission followed by prolonged, spectrally softer extended emission (EE-SGRBs) have been suggested to arise from compact object mergers6-8. Compact object mergers are of great astrophysical importance as the only confirmed site of rapid neutron capture (r-process) nucleosynthesis, observed in the form of so-called kilonovae9-14. Here we report the discovery of a possible kilonova associated with the nearby (350 Mpc), minute-duration GRB 211211A. The kilonova implies that the progenitor is a compact object merger, suggesting that GRBs with long, complex light curves can be spawned from merger events. The kilonova of GRB 211211A has a similar luminosity, duration and colour to that which accompanied the gravitational wave (GW)-detected binary neutron star (BNS) merger GW170817 (ref. 4). Further searches for GW signals coincident with long GRBs are a promising route for future multi-messenger astronomy.

Detection of GeV Emission from an Ultralong Gamma-Ray Burst with the Fermi Large Area Telescope

GRB 220627A, detected by Fermi Gamma-ray Burst Monitor (GBM), shows two episodes of gamma-ray emission, which are separated by a ∼700 s long quiescent phase. Due to similar temporal shapes and spectra in the two episodes, GRB 220627A is speculated to be a gravitationally lensed gamma-ray burst (GRB). We analyze Fermi Large Area Telescope (LAT) data and find that about 49 gamma-ray photons above 100 MeV come from the GRB during the first episode, while there are no photons above 100 MeV in the second episode. Based on the broadband spectral study of the two episodes, the gravitationally lensing scenario can be ruled out at a high confidence level and we thus conclude that GRB 220627A is an intrinsically ultralong GRB with the prompt burst emission lasting longer than 1000 s. It is then the first case that GeV emission is detected from an ultralong GRB. We find that a short spike seen in the LAT light curve is also present in GBM detectors that see the burst, suggesting a common internal region of emission across the entire Fermi energy range. The detection of a 15.7 GeV photon during the early prompt phase places a lower limit of Γ ≥ 300 on the bulk Lorentz factor of the GRB ejecta. The constraint on the bulk Lorentz factor could shed light on the origin of ultralong GRBs.

Practical Aspects of Instantaneous Magnetization Power Functions of Silicon Iron Laminations

Magnetic energy loss P of SiFe steel represents a key factor for the efficiency of soft magnetic machine cores. Traditionally, they are operated with 50 Hz (or 60 Hz), a frequency value that yields rather balanced portions of hysteresis loss and eddy current loss. In equivalent circuits of transformers, P tends to be represented by a magnetic power resistance RM, as a constant. For the most important case of sinusoidal induction B of 50 Hz, this would correspond to an instantaneous magnetization power function p(t) that is sinusoidal as well, however, with 100 Hz (or 120 Hz). On the other hand, from complex, non-linear mechanisms of hysteresis, it is obvious that p(t) should be strongly non-sinusoidal, even for exactly sinusoidal B(t). So far, almost all corresponding instantaneous investigations were restricted to calculated modelling of loss portions and transient modelling. On the other hand, for the first time, the present study was focussed on functions p(t) as measured at IEC-standardized samples of industrially relevant steel. Practical evaluations are discussed with respect to the revealed “history” of magnetization processes, as well as for product characterization. For these tasks, a novel digitized “Low-mass Single Sheet Tester” was developed that was applied for both non-oriented steel (NO) and grain-oriented steel (GO), for 50 Hz. Interpretations proved to be favoured by relating p(t) to total P, according to an instantaneous power ratio. As a result, both steel types revealed strongly non-sinusoidal power functions, with short durations of negative p. Negative p proved to be most pronounced for NO steel, as a measure for the onset of reversible turns of atomic moments. As a consequence, p(t) comprises strong upper harmonics of 200 Hz and even 300 Hz. Based on theoretical considerations, we split p(t) in a dissipative loss power function pL(t) and in a potential energy power function pP(t). Finally, we used p(t) to determine the corresponding power resistance RM(t) that proves to be a distinctly nonlinear function as well. It resembles a rectified co-sinus, also exhibiting short negative spikes that reflect the crystallographic dis-orientation of the polycrystalline material.

Preparation for Denitrification and Phenotypic Diversification at the Cusp of Anoxia: a Purpose for N2O Reductase Vis-à-Vis Multiple Roles of O2.

Adaptation to anoxia by synthesizing a denitrification proteome costs metabolic energy, and the anaerobic respiration conserves less energy per electron than aerobic respiration. This implies a selective advantage of the stringent O2 repression of denitrification gene transcription, which is found in most denitrifying bacteria. In some bacteria, the metabolic burden of adaptation can be minimized further by phenotypic diversification, colloquially termed "bet-hedging," where all cells synthesize the N2O reductase (NosZ) but only a minority synthesize nitrite reductase (NirS), as demonstrated for the model strain Paracoccus denitrificans. We hypothesized that the cells lacking NirS would be entrapped in anoxia but with the possibility of escape if supplied with O2 or N2O. To test this, cells were exposed to gradual O2 depletion or sudden anoxia and subsequent spikes of O2 and N2O. The synthesis of NirS in single cells was monitored by using an mCherry-nirS fusion replacing the native nirS, and their growth was detected as dilution of green, fluorescent fluorescein isothiocyanate (FITC) stain. We demonstrate anoxic entrapment due to e--acceptor deprivation and show that O2 spiking leads to bet-hedging, while N2O spiking promotes NirS synthesis and growth in all cells carrying NosZ. The cells rescued by the N2O spike had much lower respiration rates than those rescued by the O2 spike, however, which could indicate that the well-known autocatalytic synthesis of NirS via NO production requires O2. Our results bring into relief a fitness advantage of pairing restrictive nirS expression with universal NosZ synthesis in energy-limited systems. IMPORTANCE Denitrifying bacteria have evolved elaborate regulatory networks securing their respiratory metabolism in environments with fluctuating oxygen concentrations. Here, we provide new insight regarding their bet-hedging in response to hypoxia, which minimizes their N2O emissions because all cells express NosZ, reducing N2O to N2, while a minority express NirS + Nor, reducing NO2- to N2O. We hypothesized that the cells without Nir were entrapped in anoxia, without energy to synthesize Nir, and that they could be rescued by short spikes of O2 or N2O. We confirm such entrapment and the rescue of all cells by an N2O spike but only a fraction by an O2 spike. The results shed light on the role of O2 repression in bet-hedging and generated a novel hypothesis regarding the autocatalytic nirS expression via NO production. Insight into the regulation of denitrification, including bet-hedging, holds a clue to understanding, and ultimately curbing, the escalating emissions of N2O, which contribute to anthropogenic climate forcing.

An auditory-responsive interneuron descending from the cricket brain: a new element in the auditory pathway.

Crickets receive auditory information from their environment via ears located on the front legs. Ascending interneurons forward auditory activity to the brain, which houses a pattern recognition network for phonotaxis to conspecific calling songs and which controls negative phonotaxis to high-frequency sound pulses. Descending brain neurons, however, which are clearly involved in controlling these behaviors, have not yet been identified. We describe a descending auditory-responsive brain neuron with an arborization pattern that coincides with the ring-like auditory neuropil in the brain formed by the axonal arborizations of ascending and local interneurons, indicating its close link to auditory processing. Spiking activity of this interneuron occurs with a short latency to calling song patterns and the neuron copies the sound pulse pattern. The neuron preferentially responds to short sound pulses, but its activity appears to be independent of the calling song pattern recognition process. It also receives a weaker synaptic input in response to high-frequency pulses, which may contribute to its short latency spiking responses. This interneuron could be a crucial part in the auditory-to-motor transformation of the nervous system and contribute to the motor control of cricket auditory behavior.