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The Murchison Widefield Array (MWA) is an open access telescope dedicated to studying the low-frequency (80–300 MHz) southern sky. Since beginning operations in mid-2013, the MWA has opened a new observational window in the southern hemisphere enabling many science areas. The driving science objectives of the original design were to observe 21 cm radiation from the Epoch of Reionisation (EoR), explore the radio time domain, perform Galactic and extragalactic surveys, and monitor solar, heliospheric, and ionospheric phenomena. All together
programs recorded 20 000 h producing 146 papers to date. In 2016, the telescope underwent a major upgrade resulting in alternating compact and extended configurations. Other upgrades, including digital back-ends and a rapid-response triggering system, have been developed since the original array was commissioned. In this paper, we review the major results from the prior operation of the MWA and then discuss the new science paths enabled by the improved capabilities. We group these science opportunities by the four original science themes but also include ideas for directions outside these categories.
The Murchison Widefield Array (MWA) is an electronically steered low-frequency (<300 MHz) radio interferometer, with a ‘slew’ time less than 8 s. Low-frequency (∼100 MHz) radio telescopes are ideally suited for rapid response follow-up of transients due to their large field of view, the inverted spectrum of coherent emission, and the fact that the dispersion delay between a 1 GHz and 100 MHz pulse is on the order of 1–10 min for dispersion measures of 100–2000 pc/cm3. The MWA has previously been used to provide fast follow-up for transient events including gamma-ray bursts (GRBs), fast radio bursts (FRBs), and gravitational waves, using systems that respond to gamma-ray coordinates network packet-based notifications. We describe a system for automatically triggering MWA observations of such events, based on Virtual Observatory Event standard triggers, which is more flexible, capable, and accurate than previous systems. The system can respond to external multi-messenger triggers, which makes it well-suited to searching for prompt coherent radio emission from GRBs, the study of FRBs and gravitational waves, single pulse studies of pulsars, and rapid follow-up of high-energy superflares from flare stars. The new triggering system has the capability to trigger observations in both the regular correlator mode (limited to ≥0.5 s integrations) and using the Voltage Capture System (VCS, 0.1 ms integration) of the MWA and represents a new mode of operation for the MWA. The upgraded standard correlator triggering capability has been in use since MWA observing semester 2018B (July–Dec 2018), and the VCS and buffered mode triggers will become available for observing in a future semester.
We apply two methods to estimate the 21-cm bispectrum from data taken within the Epoch of Reionisation (EoR) project of the Murchison Widefield Array (MWA). Using data acquired with the Phase II compact array allows a direct bispectrum estimate to be undertaken on the multiple redundantly spaced triangles of antenna tiles, as well as an estimate based on data gridded to the uv-plane. The direct and gridded bispectrum estimators are applied to 21 h of high-band (167–197 MHz; z = 6.2–7.5) data from the 2016 and 2017 observing seasons. Analytic predictions for the bispectrum bias and variance for point-source foregrounds are derived. We compare the output of these approaches, the foreground contribution to the signal, and future prospects for measuring the bispectra with redundant and non-redundant arrays. We find that some triangle configurations yield bispectrum estimates that are consistent with the expected noise level after 10 h, while equilateral configurations are strongly foreground-dominated. Careful choice of triangle configurations may be made to reduce foreground bias that hinders power spectrum estimators, and the 21-cm bispectrum may be accessible in less time than the 21-cm power spectrum for some wave modes, with detections in hundreds of hours.
This study aimed to investigate endoscopic revision septoplasty with semi-penetrating straight and circular incisions in patients for whom septoplasty was unsuccessful.
Patients in this study (n = 14) had a deviation of the nasal septum after septoplasty. Pre-operative and post-operative assessments were performed using a visual analogue scale and nasal endoscope. Semi-penetrating straight and circular incisions in front of the caudal septum and at the margin of the nasal septal cartilage–bone defect, respectively, were made. The mucoperichondrium and mucoperiosteum were bilaterally dissected until interlinkage with the cartilage–bone defect was achieved. Mucous membranes within the circular incision as well as the right mucoperichondrium and mucoperiosteal flaps were protected by pushing them to the right. This exposed the osteocartilaginous framework and allowed correction of the residual deviation. The patients were followed up for 30–71 months.
For nasal obstruction and headaches, a significant improvement was noted in post-operative compared to pre-operative visual analogue scale scores. No patients had septal deviations, saddle nose, false hump nose or contracture of the nasal columella.
The technique allowed exposure of the septal osteocartilaginous framework and a broad operational vision, which enabled successful correction of various deformities of the nasal septum.
The seasonality of individual influenza subtypes/lineages and the association of influenza epidemics with meteorological factors in the tropics/subtropics have not been well understood. The impact of the 2009 H1N1 pandemic on the prevalence of seasonal influenza virus remains to be explored. Using wavelet analysis, the periodicities of A/H3N2, seasonal A/H1N1, A/H1N1pdm09, Victoria and Yamagata were identified, respectively, in Panzhihua during 2006–2015. As a subtropical city in southwestern China, Panzhihua is the first industrial city in the upper reaches of the Yangtze River. The relationship between influenza epidemics and local climatic variables was examined based on regression models. The temporal distribution of influenza subtypes/lineages during the pre-pandemic (2006–2009), pandemic (2009) and post-pandemic (2010–2015) years was described and compared. A total of 6892 respiratory specimens were collected and 737 influenza viruses were isolated. A/H3N2 showed an annual cycle with a peak in summer–autumn, while A/H1N1pdm09, Victoria and Yamagata exhibited an annual cycle with a peak in winter–spring. Regression analyses demonstrated that relative humidity was positively associated with A/H3N2 activity while negatively associated with Victoria activity. Higher prevalence of A/H1N1pdm09 and Yamagata was driven by lower absolute humidity. The role of weather conditions in regulating influenza epidemics could be complicated since the diverse viral transmission modes and mechanism. Differences in seasonality and different associations with meteorological factors by influenza subtypes/lineages should be considered in epidemiological studies in the tropics/subtropics. The development of subtype- and lineage-specific prevention and control measures is of significant importance.
Cultivated pastures in southern China are being used to improve forage productivity and animal performance, but studies on grazing behaviour of goats in these cultivated pastures are still rare. In the current study, the grazing behaviour of Yunling black goats under low (5 goats/ha) and high (15 goats/ha) stocking rates (SRs) was evaluated. Data showed that the proportion of time goats spent on activities was: eating (0.59–0.87), ruminating (0.05–0.35), walking (0.03–0.06) and resting (0.01–0.03). Compared with low SR, goats spent more time eating and walking, and less time ruminating and resting under high SR. Goats had similar diet preferences under both SR and preferred to eat grasses (ryegrass and cocksfoot) more than a legume (white clover). The distribution of eating time on each forage species was more uniform under high v. low SR. Bites/step, bite weight and daily intake were greater under low than high SR. Results suggest that the SR affects grazing behaviour of goats on cultivated pasture, and identifying an optimal SR is critical for increasing bite weight and intake.
Direct numerical simulation of intense laser–solid interactions is still of great challenges, because of the many coupled atomic and plasma processes, such as ionization dynamics, collision among charged particles and collective electromagnetic fields, to name just a few. Here, we develop a new particle-in-cell (PIC) simulation code, which enables us to calculate laser–solid interactions in a more realistic way. This code is able to cover almost ‘all’ the coupled physical processes. As an application of the new code, the generation and transport of energetic electrons in front of and within the solid target when irradiated by intense laser beams are studied. For the considered case, in which laser intensity is
and pre-plasma scale length in front of the solid is
, several quantitative conclusions are drawn: (i) the collisional damping (although it is very weak) can significantly affect the energetic electrons generation in front of the target, (ii) the Bremsstrahlung radiation will be enhanced by 2–3 times when the solid is dramatically heated and ionized, (iii) the ‘cut-off’ electron energy is lowered by an amount of 25% when both collision damping and Bremsstrahlung radiations are included, and (iv) the resistive electromagnetic fields due to Ohmic heating play nonignorable roles and must be taken into account in such interactions.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
Iron-deficiency anemia is a public health concern that frequently occurs in pregnant mammals and neonatal offspring. Ferrous N-carbamylglycinate chelate (Fe-CGly) is a newly designed iron fortifier with proven effects in iron-deficient rats and weanling piglets. However, the effects of this new compound on pregnant mammals are unknown. Therefore, this experiment was conducted to evaluate the effects of Fe-CGly on sow reproductive performance and iron status of both sows and neonatal piglets. A total of 40 large-white sows after second parity were randomly assigned to two groups (n=20). They were receiving a diet including 80 mg Fe/kg as FeSO4 or Fe-CGly, respectively, from day 85 of gestation to parturition. The serum (day 110 of pregnancy) and placentas of sows were sampled. Litter size, mean weight of live born piglets, birth (live) litter weight, number of live born piglets, and the number of still-born piglets, mummies, and weak-born piglets were recorded. Once delivered, eight litters were randomly selected from the 20 litters per treatment, and one new-born male piglet (1.503±0.142 kg) from each selected litter was slaughtered within 3 h after birth from the selected litters, without colostrum ingestion. The serum, longissimus muscle, liver and kidneys of the piglets were collected. The iron status of the serum samples and the messenger RNA level of iron-related genes in the placenta, liver and kidney were analyzed. The results showed that litter weight of live born piglets was higher (P=0.030) in the Fe-CGly group (19.86 kg) than in the FeSO4 group (17.34 kg). Fe-CGly significantly increased placental iron concentration (P<0.05) of sows. It also significantly increased iron saturation and reduced the total iron-binding capacity of piglets (P<0.05) at birth. However, the results revealed that supplementation of Fe-CGly in sows reduced liver and kidney iron concentration of neonatal piglets (P<0.05), indicating decreased iron storage. In addition, the concentration of iron in the colostrum was not significantly changed. Therefore, the present results suggested that replacement of maternal FeSO4 supplement with Fe-CGly in the late-gestating period for sows could improve litter birth weight, probably via enhanced iron transportation in the placenta.
Violators of cooperation norms may be informally punished by their peers. How such norm enforcement is judged by others can be regarded as a meta-norm (i.e., a second-order norm). We examined whether meta-norms about peer punishment vary across cultures by having students in eight countries judge animations in which an agent who over-harvested a common resource was punished either by a single peer or by the entire peer group. Whether the punishment was retributive or restorative varied between two studies, and findings were largely consistent across these two types of punishment. Across all countries, punishment was judged as more appropriate when implemented by the entire peer group than by an individual. Differences between countries were revealed in judgments of punishers vs. non-punishers. Specifically, appraisals of punishers were relatively negative in three Western countries and Japan, and more neutral in Pakistan, UAE, Russia, and China, consistent with the influence of individualism, power distance, and/or indulgence. Our studies constitute a first step in mapping how meta-norms vary around the globe, demonstrating both cultural universals and cultural differences.
Information on morbidity burden of seasonal influenza in China is limited. A multiplier model was used to estimate the incidence and number of outpatient visits for seasonal influenza by age group for the 2015–2016 season in Beijing, the capital of China, based on reported numbers of influenza-like illness consultations and proportions of positive cases from influenza surveillance systems in Beijing, general consultation rates and other parameters from previous studies, surveys and surveillance systems. An estimated total of 1 190 200 (95% confidence interval (CI) 830 400–1 549 900) cases of influenza virus infections occurred in Beijing, 2015–2016 season, with an attack rate of 5·5% (95% CI 3·9–7·2%). These infections resulted in an estimated 468 280 (95% CI 70 700–606 800) outpatient visits, with an attack rate of 2·2% (95% CI 0·3–2·8%). The attack rate of influenza virus infections was highest among children aged 0–4 years (31·9% (95% CI 21·9–41·9%)), followed by children aged 5–14 years (18·7% (95% CI 12·9–24·5%)). Our study demonstrated a substantial influenza-related morbidity in Beijing, China, especially among the preschool- and school-aged children. This suggests that development or modification of seasonal influenza targeted vaccination strategies need to recognize that incidence is highest in children.
A compact hybrid rocket motor design that incorporates a dual-vortical-flow (DVF) concept is proposed. The oxidizer (nitrous oxide, N2O) is injected circumferentially into various sections of the rocket motor, which are sectored by several solid fuel “rings” (made of hydroxyl-terminated polybutadiene, HTPB) that are installed along the central axis of the motor. The proposed configuration not only increases the residence time of the oxidizer flow, it also implies an inherent “roll control” capability of the motor. Based on a DVF motor geometry with a designed thrust level of 11.6 kN, the characteristics of the turbulent reacting flow within the motor and its rocket performance were analyzed with a comprehensive numerical model that implements both real-fluid properties and finite-rate chemistry. Data indicate that the vacuum specific impulse (Isp) of the DVF motor could reach 278 s. The result from a preliminary ground test of a lab-scale DVF hybrid rocket motor (with a designed thrust level of 3,000 N) also shows promising performance. The proposed DVF concept is expected to partly resolve the issue of scalability, which remains challenging for hybrid rocket motors development.
A scheme for the improvement of proton beam quality by the optimized dragging field from the interaction of ultraintense laser pulse with a complex double-layer target is proposed and demonstrated by one-dimensional particle-in-cell (Opic1D) simulations. The complex double-layer target consists of an overdense proton thin foil followed by a mixed hydrocarbon (CH) underdense plasma. Because of the existence of carbon ions, the dragging field in the mixed CH underdense plasma becomes stronger and flatter in the location of the proton beam than that in a pure hydrogen (H) underdense plasma. The optimized dragging field can keep trapping and accelerating protons in the mixed CH underdense target to high quality. Consequently, the energy spread of the proton beam in the mixed CH underdense plasma can be greatly reduced down to 2.6% and average energy of protons can reach to 9 GeV with circularly polarized lasers at intensities 2.74 × 1022 W/cm2.
Through-Silicon-Via (TSV) is considered to be the most potential solution for 3D electronic packaging, and the mechanical properties of TSV-Cu are critical for TSV reliability improving. In this paper, to make deeply understand the creep behavior of TSV-Cu, nanoindentation creep tests were conducted to obtain its creep parameters. At first, the TSV specimens were fabricated by means of a typical TSV manufacturing process. Then a combination programmable procedure of the constant indentation strain rate method and the constant load method was employed to study the creep behavior of TSV-Cu. To understand the influence of the previous loading schemes, including the different values of the indentation strain and the maximum depths, the nanoindentation creep tests under different loading conditions were conducted. The values of creep strain rate sensitivity m were derived from the corresponding displacement-holding time curves, and the mean value of m finally determined was 0.0149. The value of m is considered no obvious correlation with the different indentation strain rates and the maximum depths by this method. Furthermore, the mechanism for the room temperature creep was also discussed, and the grain boundaries might play an significant role in this creep behavior.
Cattleyak (hybrid of cattle and yak) exhibit higher capability in adaptability and production than cattle and yak, while the infertility of F1 males greatly restricts the effective utilization of this hybrid and little progress has been made on investigating the mechanisms of the cattleyak infertility. Cattleyak individuals at three development stages (10, 12 and 14-month old) were sampled in this work and the isobaric tag for relative and absolute quantification method was employed to identify differences between their testicular proteomes. The proteomic analysis identified 318 proteins differentially expressed with significance at 12-month stage and 327 at 14-month compared with 10-month stage, respectively. Compared with the testicular proteome from 10-month cattleyak, the gene ontology (GO) annotations of the differentially expressed proteins at 12 months did not indicate significant differences from those at 14 months, which confirmed the histological observation that germ cell reduction was more obvious and spermatogenic arrest may become more serious in 12-month-old cattleyak. On the other hand, 56 differentially expressed proteins were coexpressed at 12 and 14-month stage compared with 10-month stage, in which 32 proteins were upregulated and 24 downregulated. GO analysis revealed that most of the differently expressed proteins were involved in the molecular function of catalytic activity, transporter activity, oxidoreductase activity and protein binding. Further analysis indicated that the differently expressed proteins including testis-expressed protein 101 precursor, RNA-binding motif protein, X chromosome, putative RNA-binding protein 3, heparin-binding proteins, tudor domain-containing protein 1, glutathione S-transferases (GSTA2, GSTP1), heat shock-related 70 kDa protein 2, estradiol 17-β-dehydrogenase11, 2,4-dienoyl-CoA reductase and peroxiredoxin-2 were possibly associated with testis development and spermatogenesis, which could be selected as candidate proteins in future study to examine the mechanisms of cattleyak infertility.
With good combustion characteristics, hydrogen has been developing as a clean alternative fuel of engines. This study is to develop a diesel/hydrogen dual fuel engine. The hydrogen was added at inlet port in a 4-cylinder direct injection turbocharged diesel engine with an EGR (Exhaust Gas Recirculation) system to investigate engine performance and exhaust pollutant. The measured items are composed of the gas pressure of cylinder, crank angle, consumption rate of diesel, consumption rate of hydrogen, air flow rate, emissions (HC, CO2, NOX, and Smoke), and so on. The authors analyze how the addition of hydrogen with EGR system influences the engine performance and emissions. The diesel/hydrogen dual fuel turbocharged engine can increase the brake thermal efficiency with a greater decrease in emissions compared with the turbocharged diesel engine. Furthermore, the authors little altered the engine structure to get the positive effect of energy saving and pollutant decreasing.
The present study investigated the effects of different levels of urea nitrogen (N) fertilizer on nutrient accumulation, in vitro rumen gas production and fermentation characteristics of forage oat straw (FOS) from oats (Avena sativa L. ‘Qinghai 444’) grown in the Tibet region of China. Fertilizer, applied at seeding (day 1), stem elongation (days 52–54) and heading (days 63–67), increased plant height and prolonged the maturity stage of the plant by 4–11 days compared with the non-fertilized control. Oat plants were harvested at maturity at the node 3–4 cm above ground, and then separated into grains and FOS. Both FOS and grain yields increased quadratically with increasing N fertilization, and their theoretical maximums occurred at the N fertilizing rates of 439 and 385 kg/ha, respectively. Increases in N fertilization did not affect the hemicellulose content of FOS, but substantially promoted the accumulation of crude protein, cellulose and lignin, resulting in a decrease in the energy content available for metabolism. A 72-h incubation of FOS with rumen fluids from lactating cows showed that increasing N resulted in FOS that showed a slower fermentation rate, decreased in vitro dry matter disappearance and lower cumulative gas production, but unchanged fermentation gas composition. Nitrogen fertilization increased the final pH in culture fluids and decreased the microbial volatile fatty acid (VFA) production. The molar proportions of acetate and propionate were not affected, but molar propionate proportion decreased linearly with increasing urea fertilization, and consequently, the ratio of lipogenic (e.g., acetate and butyrate)-to-glucogenic acids (propionate) tended to increase. In brief, increasing urea N fertilization promoted the growth of forage oats and increased the biomass yield as well as the crude protein and cellulose content of FOS. Considering the negative effect of increased lignin content on nutrient digestibility and total VFA production, the suggested range of urea N fertilization is 156–363 kg N/ha for forage oats planted in Tibet to retain the nutritive value of FOS in the rumen.
The genetic influences in human brain structure and function and impaired functional connectivities are the hallmarks of the schizophrenic brain. To explore how common genetic variants affect the connectivities in schizophrenia, we applied genome-wide association studies assaying the abnormal neural connectivities in schizophrenia as quantitative traits.
We recruited 161 first-onset and treatment-naive patients with schizophrenia and 150 healthy controls. All the participants underwent scanning with a 3 T-magnetic resonance imaging scanner to acquire structural and functional imaging data and genotyping using the HumanOmniZhongHua-8 BeadChip. The brain-wide association study approach was employed to account for the inherent modular nature of brain connectivities.
We found differences in four abnormal functional connectivities [left rectus to left thalamus (REC.L–THA.L), left rectus to right thalamus (REC.L–THA.R), left superior orbital cortex to left thalamus (ORBsup.L–THA.L) and left superior orbital cortex to right thalamus (ORBsup.L–THA.R)] between the two groups. Univariate single nucleotide polymorphism (SNP)-based association revealed that the SNP rs6800381, located nearest to the CHRM3 (cholinergic receptor, muscarinic 3) gene, reached genomic significance (p = 1.768 × 10−8) using REC.L–THA.R as the phenotype. Multivariate gene-based association revealed that the FAM12A (family with sequence similarity 12, member A) gene nearly reached genomic significance (nominal p = 2.22 × 10–6, corrected p = 0.05).
Overall, we identified the first evidence that the CHRM3 gene plays a role in abnormal thalamo-orbital frontal cortex functional connectivity in first-episode treatment-naive patients with schizophrenia. Identification of these genetic variants using neuroimaging genetics provides insights into the causes of variability in human brain development, and may help us determine the mechanisms of dysfunction in schizophrenia.