Search

Electrically charged particles can be created by the decay of strong enough electric fields, a phenomenon known as the Schwinger mechanism1. By electromagnetic duality, a sufficiently strong magnetic field would similarly produce magnetic monopoles, if they exist2. Magnetic monopoles are hypothetical fundamental particles that are predicted by several theories beyond the standard model3–7but have never been experimentally detected. Searching for the existence of magnetic monopoles via the Schwinger mechanism has not yet been attempted, but it is advantageous, owing to the possibility of calculating its rate through semi-classical techniques without perturbation theory, as well as that the production of the magnetic monopoles should be enhanced by their finite size8,9and strong coupling to photons2,10. Here we present a search for magnetic monopole production by the Schwinger mechanism in Pb–Pb heavy ion collisions at the Large Hadron Collider, producing the strongest known magnetic fields in the current Universe11. It was conducted by the MoEDAL experiment, whose trapping detectors were exposed to 0.235 per nanobarn, or approximately 1.8 × 109, of Pb–Pb collisions with 5.02-teraelectronvolt center-of-mass energy per collision in November 2018. A superconducting quantum interference device (SQUID) magnetometer scanned the trapping detectors of MoEDAL for the presence of magnetic charge, which would induce a persistent current in the SQUID. Magnetic monopoles with integer Dirac charges of 1, 2 and 3 and masses up to 75 gigaelectronvolts per speed of light squared were excluded by the analysis at the 95% confidence level. This provides a lower mass limit for finite-size magnetic monopoles from a collider search and greatly extends previous mass bounds.

Oral semaglutide is the first oral formulation of a glucagon-like peptide-1 (GLP-1) receptor agonist developed for the treatment of type 2 diabetes. We aimed to compare the efficacy and safety of flexible dose adjustments of oral semaglutide with sitagliptin 100 mg.

Longitudinal variations of airglow emission rate are prominent in all midlatitude nighttime O(1S) lower thermospheric data obtained with the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). The pattern generally appears as a combination of zonal waves 1, 2, 3, and 4 whose phases propagate at different rates. Sudden localized enhancements of 2 to 4 days duration are sometimes evident, reaching vertically integrated emission rates of 400 R, a factor of 10 higher than minimum values for the same day. These are found to occur when the four wave components come into the same phase at one longitude. It is shown that these highly localized longitudinal maxima are consistent with the historical phenomena known as “bright nights” in which the surroundings of human dark night observers were seen to be illuminated by this enhanced airglow. For centuries, going back to the Roman era, people have recorded experiences of brightened skies during the night, called “bright nights.” Currently, scientists study airglow, an emission of light from the high atmosphere, 100 km above us. Satellite observations of a green airglow have shown that it consists of waves 1, 2, 3, and 4 around the earth. It happens that when the peaks of the different waves coincide there is an airglow brightening, and this article demonstrates that this event produces a bright night. The modern data are shown to be entirely consistent with the historical observations. Historical accounts of naked‐eye “bright nights” have been reported for centuriesCandidate airglow bright night events have been identified in the WINDII satellite data setIt is found that these are the result of the infrequent superposition of zonal waves of zonal wave numbers 1–4

The Abelian decomposition of QCD which decomposes the gluons to the color neutral binding gluons and the colored valence gluons shows that QCD can be viewed as the restricted QCD (RCD) made of the binding gluons which has the valence gluons as colored source, and simplifies the QCD dynamics greatly. In particular, it tells that the gauge covariant valence gluons can be treated as the constituents of hadrons, and generalizes the quark model to the quark and valence gluon model. So it provides a comprehensive picture of glueballs and their mixing with quarkoniums, and predicts new hybrid hadrons made of quarks and valence gluons. We discuss how these predictions could be confirmed experimentally. In particular we present a systematic search for the ground state glueballs and their mixing with quarkoniums below 2 GeV in 0++, 2++, and 0−+ channels within the framework of QCD, and predict the relative branching ratios of the radiative decay of ψ to the physical states. [ABSTRACT FROM AUTHOR]

We compare two competing conjectures of the color confinement in QCD, the monopole condensation and the Abelian dominance, and show that it is the monopole condensation that is responsible for the confinement. To demonstrate this we present a new gauge-invariant integral expression of the one-loop QCD effective action which has no infrared divergence. With this we show that, just as the Gliozzi-Scherk-Olive projection restores the supersymmetry and modular invariance in NSR string theory, the color reflection invariance ("the C projection") assures the gauge invariance and the stability of the monopole condensation. This establishes the monopole dominance in QCD. In doing so we point out critical defects in the calculation of the Savvidy-Nielsen-Olesen effective action. [ABSTRACT FROM AUTHOR]

This article presents a novel diagnostic algorithm based on wavelet packet transform. Although existing fault diagnostic techniques may detect the occurrence of failure or excessive malfunction in a system, they rarely reveal such detailed information as fault position, not to mention their reduced effectiveness in a system whose fault feature is not so pronounced. The proposed algorithm takes advantage of time—frequency localized features of wavelet packets in order to classify the system condition and pinpoint the fault position. Fisher's linear discriminant is used to classify system conditions, all the wavelet packets are exhaustively searched in order to unravel the optimal base (or packet) that discriminates different system conditions based on the Fisher value. It is the time—frequency localized feature of the wavelet packet that further makes it possible to detect fault position and even faulty component in the bevel gear. The proposed algorithm is validated using a machine fault simulator that consists of a motor, a bevel gear, and a bearing, where the condition of the bevel gear may be varied to simulate normal, cracked, and broken conditions using vibration signal. It turns out that the proposed algorithm precisely locates fault position as well as identifies system conditions.

In this study, we characterized the effects of 25-hydroxyvitamin D3(25-OH D3) and manipulated dietary cation-anion difference (DCAD) on the performance, urine pH, serum constituents, carcass traits, tissue residual vitamin D and its metabolites, beef tenderness, and mRNA and protein concentrations of Ca-dependent proteinases in LM using 24 cull native Korean cows. The cows were divided into 3 groups of 8: control, 25-OH D3supplemented (25-OH D3), and manipulated DCAD plus 25-OH D3supplemented (DCAD+25-OH D3). Cows receiving 25-OH D3or DCAD+25-OH D3were dosed with 125 mg of 25-OH D36 d before slaughter. The manipulated DCAD (−10 mEq/ 100 g of DM) diet was fed from 20 to 6 d (14 d) before slaughter. The DCAD+25-OH D3treatment decreased urine pH and increased serum Ca concentrations. Although the vitamin D concentrations in LM, liver, and kidney were not affected by 25-OH D3or DCAD+25-OH D3, muscle tissue 25-OH D3concentrations were increased by both regimens. Serum 25-OH D3concentrations were increased by 25-OH D3supplementation, and the increase was even greater for DCAD+25-OH D3. The same pattern was observed for serum 1,25- (OH)2D3. However, the LM concentration of 1,25-(OH)2D3was less for DCAD+25-OH D3than for control. Although Ca concentrations of LM increased numerically in response to 25-OH D3supplementation, no statistical differences in Warner-Bratzler shear force or sensory traits of LM were detected. The LM of cows receiving 25-OH D3with or without manipulated DCAD had greater concentrations of μ-calpain and m-calpain mRNA, whereas the reverse was observed for calpastatin mRNA. Expression of μ-calpain protein was increased relative to control by DCAD+25-OH D3. The amount of 25-OH D3and manipulated DCAD administered to cull native Korean cows was insufficient to improve tenderness of beef by increasing muscle Ca concentration. However, DCAD+25-OH D3induced greater expressions of μ-calpain protein as well as mRNA.

The analgesic effects of intranasal delivery of leucine enkephalin (Leu‐Enk) and its synthetic analogue [D‐ala2]‐leucine enkephalinamide (YAGFL) with or without enzyme inhibitors and/or absorption enhancers were investigated using the acetic acid‐induced writhing test in mice. The analgesic activity was significantly affected by the time delay after the administration of Leu‐Enk; the inhibition rates for the groups administered with acetic acid 5 min and 30 min after the administration of Leu‐Enk were 56.40 + 8.54 and 17.98 + 7.07%, respectively. The addition of enzyme inhibitors and absorption enhancers markedly increased the inhibition rate of Leu‐Enk and YAGFL; their inhibition rates were about four times and twice those without any enzyme inhibitor or absorption enhancer, respectively. The enzyme inhibitors and absorption enhancers that produced the highest inhibition rates of Leu‐Enk and YAGFL were azelaic acid (1%), thimerosal (0.5% mM, TM), ethylenediamine‐tetraacetic acid (5 mM, EDTA) and L‐α‐lysophosphatidylcholine (0.5%, LPC), and TM (0.5 mM), EDTA (5 mM), LPC (0.5%) and povidone (5%), respectively. The ED50 value of both enkephalins was also determined and found to be about 13 μg kg−1, which is 850 and 60 times more potent than literature values for ketoprofen and morphine, respectively. Based on these results it was concluded that Leu‐Enk or YAGFL could exert very high analgesic activity when administered nasally with a combination of inhibitors and absorption enhancers as compared with other analgesics.

This paper presents a systematic design methodology and some fundamental insights into observer design for the class of Lipschitz nonlinear systems. The existence of an asymptotically stable observer is shown to be guaranteed when the distance to unobservability is larger than the Lipschitz constant of the nonlinear system. An analytical solution for the observer is provided in this case. A methodology for the use of a coordinate transformation is then developed so as to reduce the Lipschitz constant and increase the distance to unobservability in the new coordinates. The methodology is directly applicable to the important class of feedback linearizable systems. The developed theory is used successfully in the design of an observer for a flexible joint robotic system.

Our interest in improving the efficiency of targeted scission reagents has prompted us to study the influence of ring substituents on the nuclease activity of 1,10-phenanthroline−copper conjugated to oligonucleotides and DNA-binding proteins. Since methyl substitution at all but the 2 and 9 positions enhances the copper-dependent chemical nuclease activity of 1,10-phenanthroline, we have compared the reactivity of conjugates prepared from 5-(aminomethyl)-1,10-phenanthroline (MOP) to those of conjugates prepared from 5-amino-1,10-phenanthroline (amino-OP). Tethering MOP derivatives to the Escherichia coli Fis protein enhances DNA scission several-fold at the weaker cleavage sites initially observed with conjugates prepared from amino-OP. However, scission efficiency is not increased at the stronger cleavage sites, or when scission is targeted to single-stranded DNA by a complementary oligonucleotide. These results are consistent with a change in the rate-determining step for cleavage associated with the differential accessibility of the DNA-bound coordination complex to solvent and reductant. Although the free bis cuprous complex of 2,9-dimethyl-1,10-phenanthroline (neocuproine) is redox-inactive, an oligonucleotide tethered to neocuproine through C5 of the phenanthroline ring efficiently cleaves a complementary DNA sequence. These results establish that the nucleolytic species in targeted scission is the 1:1 cuprous complex and suggest that the oxidative reaction proceeds through a copper−oxo intermediate rather than a metal-coordinated peroxy species. However, substituents at the 2 and 9 positions of the ligand will often hinder close approach of the phenanthroline−copper moiety to the oxidatively sensitive ribose as shown by the preference of the oligonucleotide-targeted chimera for cleavage of single-stranded regions and the failure of neocuproine−DNA-binding protein chimeras and a C2-tethered chimera to cleave DNA.

A low-order model of rapid thermal processing (RTP) of semiconductor wafers is derived. The first-principles nonlinear model describes the static and dynamic thermal behavior of a wafer with approximate spatial temperature uniformity undergoing rapid heating and cooling in a multilamp RTP chamber. The model is verified experimentally for a range of operating temperatures from 400° C to 900° C and pressures of 1 Torr and 1 atmosphere in an inert N2 environment. Theoretical predictions suggest model validity over a still wider range of operating conditions. One advantage of the low-order model over previous high-order and statistical models is that the proposed model contains a small number of fundamental parameters and functions that, if necessary, are easily identifiable. Furthermore, because of reduced computational complexity, the low-order model can be used in real-time predictive applications including signal processing and process control design.

We discuss the possible modification of Einstein’s theory of gravitation due to the fifth force generated by the Kaluza-Klein dilaton. In particular we discuss the gravitational red-shift, the deflection of light, the precession of perihelia, and the time-delay of radar echo around a spherically symmetric black hole in a 7-dimensional Kaluza-Klein unification which hasE2as the internal isometry. It is shown that the long-range effect of the higherdimensional fifth force is characterized by the dilatonic charge carried by the black hole even when it is neutral.

We consider Weyl symmetric structure of the classical vacuum in quantum chromodynamics. In the framework of formalism of gauge invariant Abelian projection, we show that classical vacuums can be constructed in terms of Killing vector fields on the group SU(3). Consequently, homotopic classes of Killing vector fields determine the topological structure of the vacuum. In particular, the second homotopy group π2(SU(3)/U(1)×U(1)) describes all topologically nonequivalent vacuums that are classified by two topological numbers. Starting with a given Killing vector field, one can construct vacuums forming a Weyl sextet representation. An interesting feature of SU(3) gauge theory is that it admits a Weyl symmetric vacuum represented by a linear superposition of the vacuums from the Weyl vacuum sextet. A nontrivial manifestation of the Weyl symmetry is demonstrated on monopole solutions. We construct a family of finite energy monopole solutions in Yang-Mills-Higgs theory that includes the Weyl monopole sextet. We conjecture that a similar Weyl symmetric vacuum structure can be realized at quantum level in quantum chromodynamics. [ABSTRACT FROM AUTHOR]

The Abelian decomposition of QCD which decomposes the gluons to the color neutral binding gluons (the neurons) and the colored valence gluons (the chromons) gauge independently naturally generalizes the quark model to the quark and chromon model which could play the central role in hadron spectroscopy. We discuss the color reflection symmetry, the fundamental symmetry of the quark and chromon model, and explain how it describes the glueballs and the glueball-quarkonium mixing in QCD. We present the numerical analysis of glueball-quarkonium mixing in 0++, 2++, and 0-+ sectors below 2 GeV and show that in the 0++ sector f0(500) and f0(1500), in the 2++ sector f2(1950), and in the 0-+ sector η(1405) and η(1475) could be identified as the predominant glueball states. We discuss the physical implications of our result. [ABSTRACT FROM AUTHOR]