The magnetochiral effect (MCE) of phonons, a nonreciprocal acoustic propagation arising due to symmetry principles, is demonstrated in the chiral-lattice ferrimagnet Cu_{2}OSeO_{3}. Our ...high-resolution ultrasound experiments reveal that the sound velocity differs for parallel and antiparallel propagation with respect to the external magnetic field. The sign of the nonreciprocity depends on the chirality of the crystal in accordance with the selection rule of the MCE. The nonreciprocity is enhanced below the magnetic ordering temperature and at higher ultrasound frequencies, which is quantitatively explained by a proposed magnon-phonon hybridization mechanism.
Production of diploid males is disadvantageous for populations of haplodiploid species, because it increases the genetic load and decreases fitness. In social species, the damage becomes more serious ...because of increased colony mortality and decreased colony growth rates. As a parameter to quantify diploid male production, the proportion of diploids that are males,
Φ
, has been estimated using multiple-loci marker genotypes. In these studies,
Φ
is separately estimated for individual marker locus, and then the estimates are averaged over marker loci. In this paper, we propose a simple method for combining genotypes of multiple-marker loci to obtain a single estimate of
Φ
, which is expected to enhance the quality of estimate. As an application,
Φ
in a threatened bumble bee population in Japan is estimated from genotype data of multiple microsatellite loci. Under the separate analysis of individual marker locus the detectability of diploid males, measured by the probability that a diploid is heterozygous, is within the range of 0.196–0.554, whereas the detectability from the proposed method increases to 0.834, giving an estimate of
Φ
with a higher degree of precision.
Abstract Background Mortality following cardiac arrest remains high, and point-of-care ultrasound has been suggested to improve outcomes from advanced cardiac life support (ACLS), but no large ...studies have explored how point-of-care ultrasound should be incorporated into ACLS. Our aim was to determine whether detection of cardiac activity by ultrasound during ACLS is associated with improved survival. Methods We conducted a non-randomized, prospective, protocol-driven observational study. It was a 20 site, multi-center study of emergency departments (EDs) across United States and Canada. Patients presenting with out-of-hospital cardiac arrest or in-ED arrest with pulseless electrical activity or asystole were included. An initial ultrasound was performed at the beginning and end of ACLS. The primary outcome was percentage of patients that survive to hospital admission. Subgroups for additional analysis were identified through univariate and multivariate analysis. Secondary outcomes included survival to hospital discharge and return of spontaneous circulation. Findings 953 patients presenting May 2011 to November 2014 were enrolled with 793 included in the analysis. Overall 208 patients (26.2%) survived the initial resuscitation, 114 (14.4%) survived to hospital admission, and 13 (1.6%) surviving to hospital discharge. Cardiac activity on initial US was the variable most associated with survival at all time points. On multivariate regression modeling, cardiac activity was associated with a greater incidence of survival to hospital admission (OR 3.6, 2.2 to 5.9) and hospital discharge (OR 5.7, 1.5 to 21.9). The lack of cardiac activity on initial US was strongly associated with non-survival, but 0.6% (95% CI − 0.3 to 2.3) of patients with no cardiac activity survived to discharge. Ultrasound identified findings during the resuscitation that responded to interventions outside of standard ACLS interventions. Patients with pericardial effusion who underwent pericardiocentesis demonstrated higher survival rates (15.4%) compared to all others (1.3%). Conclusion The presence of cardiac activity at the initiation of ACLS in the ED was the variable most associated with survival following cardiac arrest. Point-of-care ultrasound during cardiac arrest can identify patients with higher likelihood of survival to hospital discharge, and can identify interventions outside of the standard ACLS algorithm. Point-of-care ultrasound should be integrated into ACLS algorithms.
Chimeric polyhydroxyalkanoate synthase PhaCAR is characterized by the capacity to incorporate unusual glycolate (GL) units and spontaneously synthesize block copolymers. The GL and 3-hydroxybutyrate ...(3HB) copolymer synthesized by PhaCAR is a random-homo block copolymer, poly(GL-ran-3HB)-b-poly(3HB). In the present study, medium-chain-length 3-hydroxyhexanoate (3HHx) units were incorporated into this copolymer using PhaCAR for the first time. The coenzyme A (CoA) ligase from Pseudomonas oleovorans (AlkK) serves as a simple 3HHx-CoA supplying route in Escherichia coli from exogenously supplemented 3HHx. NMR analyses of the obtained polymers revealed that 3HHx units were randomly connected to 3HB units, whereas GL units were heterogeneously distributed. Therefore, the polymer is composed of 2 segments: P(3HB-co-3HHx) and P(GL-co-3HB-co-3HHx). The thermal and mechanical properties of the terpolymer indicate no contiguous P(3HB) segments in the material, consistent with the NMR results. Therefore, PhaCAR synthesized the novel block copolymer P(3HB-co-3HHx)-b-P(GL-co-3HB-co-3HHx), which is the first block polyhydroxyalkanoate copolymer comprising 2 copolymer segments.
The phonon magnetochiral effect (MChE) is the nonreciprocal acoustic and thermal transports of phonons caused by the simultaneous breaking of the mirror and time-reversal symmetries. So far, the ...phonon MChE has been observed only in a ferrimagnetic insulator Cu_{2}OSeO_{3}, where the nonreciprocal response disappears above the Curie temperature of 58 K. Here, we study the nonreciprocal acoustic properties of a room-temperature ferromagnet Co_{9}Zn_{9}Mn_{2} for unveiling the phonon MChE close to room temperature. Surprisingly, the nonreciprocity in this metallic compound is enhanced at higher temperatures and observed up to 250 K. This clear contrast between insulating Cu_{2}OSeO_{3} and metallic Co_{9}Zn_{9}Mn_{2} suggests that metallic magnets have a mechanism to enhance the nonreciprocity at higher temperatures. From the ultrasound and microwave-spectroscopy experiments, we conclude that the magnitude of the phonon MChE of Co_{9}Zn_{9}Mn_{2} mostly depends on the Gilbert damping, which increases at low temperatures and hinders the magnon-phonon hybridization. Our results suggest that the phonon nonreciprocity could be further enhanced by engineering the magnon band of materials.
Abstract
Under magnetic fields, quantum magnets often undergo exotic phase transitions with various kinds of order. The discovery of a sequence of fractional magnetization plateaus in the ...Shastry-Sutherland compound SrCu
2
(BO
3
)
2
has played a central role in the high-field research on quantum materials, but so far this system could only be probed up to half the saturation value of the magnetization. Here, we report the first experimental and theoretical investigation of this compound up to the saturation magnetic field of 140 T and beyond. Using ultrasound and magnetostriction techniques combined with extensive tensor-network calculations (iPEPS), several spin-supersolid phases are revealed between the 1/2 plateau and saturation (1/1 plateau). Quite remarkably, the sound velocity of the 1/2 plateau exhibits a drastic decrease of -50%, related to the tetragonal-to-orthorhombic instability of the checkerboard-type magnon crystal. The unveiled nature of this paradigmatic quantum system is a new milestone for exploring exotic quantum states of matter emerging in extreme conditions.
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