Fast radio bursts (FRBs) are millisecond-duration radio waves from the Universe. Even though more than 50 physical models have been proposed, the origin and physical mechanism of FRB emissions are still unknown. The classification of FRBs is one of the primary approaches to understanding their mechanisms, but previous studies classified conventionally using only a few observational parameters, such as fluence and duration, which might be incomplete. To overcome this problem, we use an unsupervised machine-learning model, the Uniform Manifold Approximation and Projection to handle seven parameters simultaneously, including amplitude, linear temporal drift, time duration, central frequency, bandwidth, scaled energy, and fluence. We test the method for homogeneous 977 sub-bursts of FRB 20121102A detected by the Arecibo telescope. Our machine-learning analysis identified five distinct clusters, suggesting the possible existence of multiple different physical mechanisms responsible for the observed FRBs from the FRB 20121102A source. The geometry of the emission region and the propagation effect of FRB signals could also make such distinct clusters. This research will be a benchmark for future FRB classifications when dedicated radio telescopes such as the square kilometer array or Bustling Universe Radio Survey Telescope in Taiwan discover more FRBs than before.

Species of epiphytic microbiota are closely associated with the fermentation performance of natural forage silage. This study aimed to evaluate the dynamic microbial communities, fermentation parameters, and aerobic stability of Napier grass silage from the same variety and growth period but harvested from three different regions (NGP1, NGP2, and NGP3). After 60 days of ensiling, triplicate silos were opened for sampling and testing aerobic stability. The epiphytic microbiota with higher relative abundances in fresh Napier grass (NGP1, NGP2, and NGP3) were Weissella, Enterobacter, and Lactococcus, respectively. After 60 days of ensiling, NGP3 exhibited higher fermentation quality, indicated by higher lactic acid (LA) concentration and lower pH than that of NGP1 and NGP2. The NH3–N content of all treatments was lower than 100 g/kg total nitrogen. Compared with NGP1 and NGP2 silage, NGP3 silage exhibited a sharp rise in pH and LA consumption during air exposure. After 7 days of air exposure, NGP3 had higher ethanol concentrations and pH. Ruminiclostridium_5, Pediococcus, and Lactobacillus predominated in NGP1, NGP2, and NGP3 silages, respectively, whereas Candida and Monascus predominated in air-exposed NGP3 silage. The bacterial co-occurrence networks from fresh samples to ensiling and air exposure became more complex; however, NGP3 had a higher negative correlation with co-occurrence after air exposure. Different regions had significant effects on the fermentation patterns, bacterial communities, and aerobic stability of Napier grass silage. This was mainly due to variable epiphytic microbiota. Higher fermentation quality of Napier grass silage may also result in accelerated spoilage due to air exposure. Candida and Monascus were primarily responsible for the lower dry matter recovery and higher ethanol contents and air exposure spoilage of Napier grass silage.

We report the unified constitutive law of vibroconvective turbulence in microgravity, i.e. $Nu \sim a^{-1} Re_{os}^\beta$ where the Nusselt number $Nu$ measures the global heat transport, $a$ is the dimensionless vibration amplitude, $Re_{os}$ is the oscillational Reynolds number and $\beta$ is the universal exponent. We find that the dynamics of boundary layers plays an essential role in vibroconvective heat transport and the $Nu$-scaling exponent $\beta$ is determined by the competition between the thermal boundary layer (TBL) and vibration-induced oscillating boundary layer (OBL). Then a physical model is proposed to explain the change of scaling exponent from $\beta =2$ in the TBL-dominant regime to $\beta = 4/3$ in the OBL-dominant regime. Our finding elucidates the emergence of universal constitutive laws in vibroconvective turbulence, and opens up a new avenue for generating a controllable effective heat transport under microgravity or even microfluidic environment in which the gravity effect is nearly absent.

Let $\mathcal {M}$ be an Ahlfors $n$-regular Riemannian manifold such that either the Ricci curvature is non-negative or the Ricci curvature is bounded from below together with a bound on the gradient of the heat kernel. In the paper [IMRN, 2022, no. 2, 1245-1269] of Brazke–Schikorra–Sire, the authors characterised the BMO function $u : \mathcal {M} \to \mathbb {R}$ by a Carleson measure condition of its $\sigma$-harmonic extension $U:\mathcal {M}\times \mathbb {R}_+ \to \mathbb {R}$. This paper is concerned with the similar problem under a more general Dirichlet metric measure space setting, and the limiting behaviours of BMO & Carleson measure, where the heat kernel admits only the so-called diagonal upper estimate. More significantly, without the Ricci curvature condition, we relax the Ahlfors regularity to a doubling property, and remove the pointwise bound on the gradient of the heat kernel. Some similar results for the Lipschitz function are also given, and two open problems related to our main result are considered.

This paper presents a language, Alda, that supports all of logic rules, sets, functions, updates, and objects as seamlessly integrated built-ins. The key idea is to support predicates in rules as set-valued variables that can be used and updated in any scope, and support queries using rules as either explicit or implicit automatic calls to an inference function. We have defined a formal semantics of the language, implemented a prototype compiler that builds on an object-oriented language that supports concurrent and distributed programming and on an efficient logic rule system, and successfully used the language and implementation on benchmarks and problems from a wide variety of application domains. We describe the compilation method and results of experimental evaluation.

Straightplasma channels are widely used to guide relativistic intense laser pulses over several Rayleigh lengths for laser wakefield acceleration. Recently, a curved plasma channel with gradually varied curvature was suggested to guide a fresh intense laser pulse and merge it into a straight channel for staged wakefield acceleration [Phys. Rev. Lett. 120, 154801 (2018)]. In this work, we report the generation of such a curved plasma channel from a discharged capillary. Both longitudinal and transverse density distributions of the plasma inside the channel were diagnosed by analyzing the discharging spectroscopy. Effects of the gas-filling mode, back pressure and discharging voltage on the plasma density distribution inside the specially designed capillary are studied. Experiments show that a longitudinally uniform and transversely parabolic plasma channel with a maximum channel depth of 47.5 μm and length of 3 cm can be produced, which is temporally stable enough for laser guiding. Using such a plasma channel, a laser pulse with duration of 30 fs has been successfully guided along the channel with the propagation direction bent by 10.4°.

We present a high-energy, hundred-picosecond (ps) pulsed mid-ultraviolet solid-state laser at 266 nm by a direct second harmonic generation (SHG) in a barium borate (BaB2O4, BBO) nonlinear crystal. The green pump source is a 710 mJ, 330 ps pulsed laser at a wavelength of 532 nm with a repetition rate of 1 Hz. Under a green pump energy of 710 mJ, a maximum output energy of 253.3 mJ at 266 nm is achieved with 250 ps pulse duration resulting in a peak power of more than 1 GW, corresponding to an SHG conversion efficiency of 35.7% from 532 to 266 nm. The experimental data were well consistent with the theoretical prediction. To the best of our knowledge, this laser exhibits both the highest output energy and highest peak power ever achieved in a hundred-ps/ps regime at 266 nm for BBO-SHG.

A growing number of Chinese firms motivate their employees through employee stock ownership plans (ESOPs). Using a sample of listed firms in China, this paper examines the impact of ESOPs on firms’ total factor productivity (TFP), as well as the mechanisms of ESOPs. The empirical results show that ESOPs have a positive impact on firm TFP. The mechanism tests convey that ESOPs increase firm TFP by promoting research and development (R&D) investment and mitigating agency costs. These results are robust after accounting for endogeneity and using alternative metrics of TFP. In addition, we find that the positive effect of ESOPs on firm TFP is more pronounced in non-state-owned firms and firms with a less severe free-riding problem. Furthermore, the effect on firm TFP is positively associated with the subscription proportion of non-executive employees in ESOPs. Overall, the results of this study underscore the important role of employee ownership in firms’ productivity improvement.

High-power continuous-wave ultraviolet lasers are useful for many applications. As ultraviolet laser sources, the wavelength switching capability and compact structure are very important to extend the applicability and improve the flexibility in practical applications. In this work, we present two simple and relatively compact schemes by laser diode pumping to obtain a watt-level single-wavelength 348.7-nm laser and discrete wavelength tunable ultraviolet lasers around 349 nm (from 334.7 to 364.5 nm) by intracavity frequency doubling based on Pr3+:YLF and $\unicode{x3b2}$-BBO crystals. The maximum output power of the single-wavelength 348.7-nm laser is 1.033 W. The output powers of the discrete wavelength tunable lasers are at the level of tens of milliwatts, except for two peaks at 348.7 and 360.3 nm with output powers of approximately 500 mW. In addition, simulations are carried out to explain the experimental results and clarify the tuning mechanisms.

Different kinds of waves and instabilities in the F-region of the ionosphere excited by the relative streaming of the dust beam to the background plasma are studied in the present paper. The dispersion relations of different waves are obtained on different time scales. It is found from our numerical results that there are both a stable upper hybrid wave on the electron vibration time scale and a stable dust ion cyclotron wave on the ion vibration time scale. However, the chaotic behaviour appears on the dust particles vibration time scale due to the relative streaming of the dust particles to the background plasma. Such instabilities may drive plasma irregularities that could affect radar backscatter from the clouds.

Listeriosis is a rare but serious foodborne disease caused by Listeria monocytogenes. This matched case–control study (1:1 ratio) aimed to identify the risk factors associated with food consumption and food-handling habits for the occurrence of sporadic listeriosis in Beijing, China. Cases were defined as patients from whom Listeria was isolated, in addition to the presence of symptoms, including fever, bacteraemia, sepsis and other clinical manifestations corresponding to listeriosis, which were reported via the Beijing Foodborne Disease Surveillance System. Basic patient information and possible risk factors associated with food consumption and food-handling habits were collected through face-to-face interviews. One hundred and six cases were enrolled from 1 January 2018 to 31 December 2020, including 52 perinatal cases and 54 non-perinatal cases. In the non-perinatal group, the consumption of Chinese cold dishes increased the risk of infection by 3.43-fold (95% confidence interval 1.27–9.25, χ2 = 5.92, P = 0.02). In the perinatal group, the risk of infection reduced by 95.2% when raw and cooked foods were well-separated (χ2 = 5.11, P = 0.02). These findings provide important scientific evidence for preventing infection by L. monocytogenes and improving the dissemination of advice regarding food safety for vulnerable populations.

Nutritional Risk Screening index is a standard tool to assess nutritional risk, but epidemiological data are scarce on controlling nutritional status (CONUT) as a prognostic marker in acute haemorrhagic stroke (AHS). We aimed to explore whether the CONUT may predict a 3-month functional outcome in AHS. In total, 349 Chinese patients with incident AHS were consecutively recruited, and their malnutrition risks were determined using a high CONUT score of ≥ 2. The cohort patients were divided into high-CONUT (≥ 2) and low-CONUT (< 2) groups, and primary outcomes were a poor functional prognosis defined as the modified Rankin Scale (mRS) score of ≥ 3 at post-discharge for 3 months. Odds ratios (OR) with 95 % confidence intervals (CI) for the poor functional prognosis at post-discharge were estimated by using a logistic analysis with additional adjustments for unbalanced variables between the high-CONUT and low-CONUT groups. A total of 328 patients (60·38 ± 12·83 years; 66·77 % male) completed the mRS assessment at post-discharge for 3 months, with 172 patients at malnutrition risk at admission and 104 patients with a poor prognosis. The levels of total cholesterol and total lymphocyte counts were significantly lower in high-CONUT patients than low-CONUT patients (P = 0·012 and < 0·001, respectively). At 3-month post discharge, there was a greater risk for the poor outcome in the high-CONUT compared with the low-CONUT patients at admission (OR: 2·32, 95 % CI: 1·28, 4·17). High-CONUT scores independently predict a 3-month poor prognosis in AHS, which helps to identify those who need additional nutritional managements.

The provenance and tectonic setting of the Lower–Middle Triassic clastic sediments from the Napo basin, South China, have been examined here using detrital modes, whole-rock geochemistry and detrital zircon U–Pb ages. Field investigations indicate that these sediments consist of fan delta, slope and turbidity fan facies with dominantly southward palaeocurrent directions. Detrital modes and geochemical characteristics of the clastic rocks indicate that they were derived from mixed magmatic arc and Palaeozoic successions in a continental island arc setting, with no significant sediment recycling. The U–Pb age spectra of sandstone detrital zircons from different stratigraphic positions are similar, with one major group (300–230 Ma), two subordinate groups (400–320 Ma and 480–420 Ma, respectively) and two scattered groups (1200–800 Ma and 2000–1700 Ma, respectively). Thus, we consider that the north late Permian – Middle Triassic volcanic rocks and the uplifted Palaeozoic sedimentary/volcanic sequences constituted the predominant sources. The detritus derived from the late Permian Emeishan mafic rocks is subordinate and limited. The pre-Devonian zircons are likely sedimentary-recycled or magmatic-captured instead of directly derived from the early Palaeozoic orogen (e.g. Yunkai massif) and Neoproterozoic Jiangnan orogen because of the topographic barrier of a magmatic arc and carbonate platform. Considering the spatial and temporal distribution characteristics of the volcanic arc and ophiolite, we suggest that the Triassic Napo basin was a fore-arc basin within a continental island arc setting, which developed in response to the northward subduction of the Babu–Cao Bang branch ocean beneath the South China Block.

We carry out direct numerical simulations of turbulent Rayleigh–Bénard convection in a square box with rough conducting plates over the Rayleigh number range $10^7\leqslant Ra\leqslant 10^9$ and the Prandtl number range $0.01\leqslant Pr\leqslant 100$. In Zhang et al. (J. Fluid Mech., vol. 836, 2018, R2), it was reported that while the measured Nusselt number $Nu$ is enhanced at large roughness height $h$, the global heat transport is reduced at small $h$. The division between the two regimes yields a critical roughness height $h_c$, and we now focus on the effects of the Prandtl number ($Pr$) on $h_c$. Based on the variations of $h_c$, we identify three regimes for $h_c(Pr)$. For low $Pr$, thermal boundary layers become thinner with increasing $Pr$. This makes the boundary layers easier to be disrupted by rough elements, leading to the decrease of $h_c$ with increasing $Pr$. For moderate $Pr$, the corner-flow rolls become much more pronounced and suppress the global heat transport via the competition between the corner-flow rolls and the large-scale circulation (LSC). As a consequence, $h_c$ increases with increasing $Pr$ due to the intensification of the corner–LSC competition. For high $Pr$, the convective flow transitions to the plume-controlled regime. As the rough elements trigger much stronger and more frequent plume emissions, $h_c$ again decreases with increasing $Pr$.

In this article, we discuss the backgrounds and technical details about several smart manufacturing projects in a tier-one electronics manufacturing facility. We devise a process to manage logistic forecast and inventory preparation for electronic parts using historical data and a recurrent neural network to achieve significant improvement over current methods. We present a system for automatically qualifying laptop software for mass production through computer vision and automation technology. The result is a reliable system that can save hundreds of man-years in the qualification process. Finally, we create a deep learning-based algorithm for visual inspection of product appearances, which requires significantly less defect training data compared to traditional approaches. For production needs, we design an automatic optical inspection machine suitable for our algorithm and process. We also discuss the issues for data collection and enabling smart manufacturing projects in a factory setting, where the projects operate on a delicate balance between process innovations and cost-saving measures.

Meiosis is a highly conserved process, and is responsible for the production of haploid gametes and generation of genetic diversity. We previously identified the transferrin receptor (TFRC) in the proteome profile of mice neonatal testes, indicating the involvement of the TFRC in meiosis. However, the exact molecular role of the TFRC in meiosis remains unclear. In this study, we aimed to determine the function of the TFRC in neonatal testicular development by TFRC knockdown using the testis culture platform. Our results showed high TFRC expression in 2-week testes, corresponding to the first meiotic division. Targeting TFRC using morpholino oligonucleotides resulted in clear spermatocyte apoptosis. In addition, we used the chromosomal spread technique to show that a deficiency of TFRC caused the accumulation of leptotene and zygotene spermatocytes, and a decrease of pachytene spermatocytes, indicating early meiotic arrest. Moreover, the chromosomes of TFRC-deficient pachytene spermatocytes displayed sustained γH2AX association, as well as SYCP1/SYCP3 dissociation beyond the sex body. Therefore, our results demonstrated that the TFRC is essential for the progression of spermatocyte meiosis, particularly for DNA double-stranded break repair and chromosomal synapsis.