Ice breaking has become one of the main problems faced by ships and other equipment operating in an ice-covered water region. New methods are always being pursued and studied to improve ice-breaking capabilities and efficiencies. Based on the strong damage capability, a high-speed water jet impact is proposed to be used to break an ice plate in contact with water. A series of experiments of water jet impacting ice were performed in a transparent water tank, where the water jets at tens of metres per second were generated by a home-made device and circular ice plates of various thicknesses and scales were produced in a cold room. The entire evolution of the water jet and ice was recorded by two high-speed cameras from the top and front views simultaneously. The focus was the responses of the ice plate, such as crack development and breakup, under the high-speed water jet loads, which involved compressible pressure ${P_1}$ and incompressible pressure ${P_2}$. According to the main cause and crack development sequence, it was found that the damage of the ice could be roughly divided into five patterns. On this basis, the effects of water jet strength, ice thickness, ice plate size and boundary conditions were also investigated. Experiments validated the ice-breaking capability of the high-speed water jet, which could be a new auxiliary ice-breaking method in the future.

The extent of the reduction of maize (Zea mays L.) kernel moisture content through drying is closely related to field temperature (or accumulated temperature; AT) following maturation. In 2017 and 2018, we selected eight maize hybrids that are widely planted in Northeastern China to construct kernel drying prediction models for each hybrid based on kernel drying dynamics. In the traditional harvest scenario using the optimal sowing date (OSD), maize kernels underwent drying from 4th September to 5th October, with variation coefficients of 1.0–1.9. However, with a latest sowing date (LSD), drying occurred from 14th September to 31st October, with variation coefficients of 1.3–3.0. In the changed harvest scenario, the drying time of maize sown on the OSD condition was from 12th September to 9th November with variation coefficients of 1.3–3.0, while maize sown on the LSD had drying dates of 26th September to 28th October with variation coefficients of 1.5–3.6. In the future harvest scenario, the Fengken 139 (FK139) and Jingnongke 728 (JNK728) hybrids finished drying on 20th October and 8th November, respectively, when sown on the OSD and had variation coefficients of 2.7–2.8. Therefore, the maize kernel drying time was gradually delayed and was associated with an increased demand for AT ⩾ 0°C late in the growing season. Furthermore, we observed variation among different growing seasons likely due to differences in weather patterns, and that sowing dates impact variations in drying times to a greater extent than harvest scenarios.

The Silurian and Devonian plant fossil record is the basis for our understanding of the early evolution of land plants, yet our appreciation of early global phytogeographic evolution has been constrained by the focus of most studies on deposits from Europe, North America, and, more recently, South China. Devonian plants have been recorded rarely from northeastern China, and among previous records, few plants have been illustrated and formally described. In this article, megafossil plants representing a Late Devonian-aged (probably Famennian) flora are described from a locality at northern Sonid Zuoqi, Inner Mongolia, NE China. The flora includes Melvillipteris sonidia new species, Archaeopteris sp., and fragments of some other plants. The new plant shows main axes and two orders of lateral branches. The first-order branches of this plant show a typical zigzag appearance and are borne in pairs on main axes. Second-order branches are straight or slightly flexed, and are borne helically or alternately on first-order branches. Sterile ultimate appendages and fertile structures of M. sonidia n. sp. are borne alternately on second-order branches. An associated palynological assemblage, as well as U-Pb ages of detrital zircon grains from adjacent horizons, are also reported, indicating a Late Devonian age in accord with the megafossil plants. The present study contributes to our appreciation of the Devonian floristic diversity of the Xing'an Block, and, through our review of the record of early vascular plants from NE China, more broadly to the understanding of the mid-latitude vegetation of the Northern Hemisphere during the Late Devonian.

In this paper the configurations of shock wave–boundary layer interactions (SWBLI) are studied theoretically and experimentally in Mach number 2 and 2.5 flows on test models with various wedge angles ranging from $9^\circ$ to $21^\circ$. The proposed theoretical method couples the free interaction theory (FIT) with the minimum entropy production (MEP) principle to predict the appearance of separation shock, resulting in convex, straight and concave separation shock waves according to different solution combinations, which agree well with current experiments. Additionally, several influences on SWBLI are studied experimentally, in which the parameters related to theoretical solutions are found mostly determining the flow configuration, and SWBLI is much more sensitive to incident shock strength than incoming flow properties. Separation could be suppressed by incident shock when the MEP solution is smaller than the FIT, while it could be intensified when the MEP solution is larger than FIT; by contrast, the effects of separation position and model mounting height could be very weak.

Imprinting, characterized by unequal expression of the offspring's genes in a parent-of-origin dependent manner, has been functionally implicated in brain development and in psychiatric disorders. In this study, unambiguous distortion in paternal but not maternal transmission of the disease-associated single-nucleotide polymorphism (SNP) rs6556547 (T/G) clearly indicated the presence of parent-of-origin effect (POE) in the GABAA receptor β2 subunit gene (GABRB2). ‘Flipping’ of allelic mRNA expression in heterozygotes of SNP rs2229944 (C/T) and the observed two-tiered distribution of mRNA expression levels in heterozygotes of the disease-associated SNP rs1816071 (G/A) furnished important support for the occurrence of imprinting at GABRB2. Imprinting in effect introduced heterozygotes from different parents-of-origin endowed with dissimilar mRNA expression capabilities. The deficit of upper-tiered expressions accounted for the lowered mRNA expression levels in the schizophrenic heterozygotes. This pointed to the necessity of differentiating between two kinds of heterozygotes of different parental origins in disease association studies on GABRB2. Bisulfite sequencing revealed hypermethylation in the neighborhood of SNP rs1816071, and methylation differences between controls and schizophrenia patients. Notably, allele-specific methylation was observed at the disease-associated SNPs rs6556547 and rs1816071. These findings raised the possibility that CpG methylation status of these sites could have an impact on the expression of GABRB2 and the risk of schizophrenia. Furthermore, the occurrence of imprinting and allele-specific methylation in the schizophrenia candidate gene GABRB2 was compatible with the epigenetic hypothesis for schizophrenia pathophysiology, thereby calling for the need to explore the role of epigenetic factors in mediating susceptibility to schizophrenia.

GABRB2, the gene for β2 subunit of the gamma-aminobutyric acid type A (GABAA) receptor, is known to display two splicing isoforms in the brain, namely β2L containing Exon 10 and β2S devoid of Exon 10. Previously, the expressions of these isoforms were correlated with both schizophrenia and various sequence polymorphisms of the gene. in the present study, a series of deletions made on Intron 9 of a minigene construct affected the expression of Exon 10, and generated additional splicing variations suggesting the existence of additional splicing variants of β2subunit. A search among brain cDNAs uncovered the two novel short forms: β2S1which is devoid of Exons 10 and 11 and bears an extended Exon 9, and β2S2 which is devoid of Exon 10 and bears a shortened Exon 11.Real-time quantitative polymerase chain reaction, performed with a cohort of 31 schizophrenics, 30 bipolar disorder and 31 controls of US population, showed that the level of β2S2 was significantly decreased in bipolar disorder, and marginally decreased in schizophrenia, while β2S1 was marginally increased in both of these psychotic disorders. Significant genotypic effects of rs1816071, rs1816072 and rs187269 on β2S2 level were observed in male schizophrenic and bipolar patients. These findings pointed to the neighborhood of Exon 10 as an alternate-splicing hot-spot, and underlined the relevance of β2 subunit isoforms to the etiology of psychotic disorders.

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 $60+$ 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.

In this paper, a novel continuous fiber reinforced piezoelectric composite (CFRPC) actuator is proposed to improve the stability and reliability of piezoelectric actuators. A piezoelectric driving structure composed of a cantilever beam and the CFRPC actuator is utilized to research the actuation performance of the CFRPC actuator. The expression of the equivalent moment for the CFRPC actuator is obtained using the equivalent load method and electro-mechanical coupling theory. Based on Euler-Bernoulli beam theory, the analytical expression of the deflection for the cantilever beam is derived. The accuracy of the obtained analytical expressions is demonstrated by finite element simulation as well as published experimental results. The actuation performance of the CFRPC actuator is investigated through the analytical expressions of the equivalent moment and deflection. The results show that the key parameters such as driving voltage, fiber volume fraction, cantilever beam height, actuator height, actuator length and actuator position have great influence on the actuation performance of the CFRPC actuator. The CFRPC actuator has good mechanical and electrical properties, and has a wide application prospect in the field of structural shape control.

This paper focus on the mechanical and martensitic transformation behaviors of axially functionally graded shape memory alloy (AFG SMA) beams. It is taken into consideration that material properties, such as austenitic elastic modulus, martensitic elastic modulus, critical transformation stresses and maximum transformation strain vary continuously along the longitudinal direction. According to the simplified linear SMA constitutive equations and Bernoulli-Euler beam theory, the formulations of stress, strain, martensitic volume fraction and governing equations of the deflection, height and length of transformed layers are derived. Employing the Galerkin’s weighted residual method, the governing differential equation of the deflection is solved. As an example, the bending behaviors of an AFG SMA cantilever beam subjected to an end concentrated load are numerically analyzed using the developed model. Results show that the mechanical and martensitic transformation behaviors of the AFG SMA beam are complex after the martensitic transformation of SMA occurs. The influences of FG parameter on the mechanical behaviors and geometrical shape of transformed regions are obvious, and should be considered in the design and analysis of AFG SMA beams in the related regions.

Life-history theory predicts a trade-off between the juvenile growth rate and adult traits related to survival. However, this hypothesized negative correlation is difficult to test robustly because many trade-offs are mild, and environmental variables, such as changes in nutrient availability, can ameliorate the trade-off or make it more pronounced. Thus, it is reasonable to expect that the expression of the trade-off can be condition-dependent. In the present study, we first examined the pre-adult life-history traits of the cotton bollworm, Helicoverpa armigera, collected from northern, central, and southern China at different temperatures. We found that the northern China population has a significantly shorter pre-adult developmental time and higher growth rate than the southern China population as a result of adaptation to the decreased seasonal length. Then, we tested for a trade-off between the juvenile growth rate and adult lifespan in different temperature and nutrient conditions. We found a negative relationship between juvenile growth rate and adult lifespan under starvation or desiccation conditions; however, a continuous supply of sugar can diminish or obviate the apparent negative relationship, in which the adult lifespan did not show a significant difference in most of the comparisons. These results suggested a resource-mediated trade-off may exist between juvenile growth rate and adult lifespan. However, the adult size may have some positive effect on the lifespan under starvation and desiccation conditions, which may affect the expression of trade-off.

Pathogenesis of pregnancy toxemia (PT) is believed to be associated with the disruption of lipid metabolism. The present study aimed to explore the underlying mechanisms of lipid metabolism disorder in the livers of ewes with PT. In total, 10 pregnant ewes were fed normally (control group) whereas another 10 were subjected to 70% level feed restriction for 15 days to establish a pathological model of PT. Results showed that, as compared with the controls, the levels of blood β-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFAs) and cholesterol were greater (P<0.05) and blood glucose level was lower (P<0.05) in PT ewes. The contents of NEFAs, BHBA, cholesterol and triglyceride were higher (P<0.05) and glycerol content was lower (P<0.05) in hepatic tissues of PT ewes than those of the controls. For ewes with PT, excessive fat vacuoles were observed in liver sections stained with hematoxylin–eosin; furthermore, inner structures of hepatocytes including nuclei, mitochondria and endoplasmic reticulum were damaged seriously according to the results of transmission electron microscope. Real-time PCR data showed that compared with the controls, the expression of hepatic genes involved in fatty acid oxidation (FAO) and triglyceride synthesis (TGS) was enhanced (P<0.05) whereas that related to acetyl-CoA metabolism (ACM) was repressed (P<0.05) in PT ewes. Generally, our results showed that negative energy balance altered the expression of genes involved in FAO, ACM and TGS, further caused lipid metabolism disorder in livers, resulting in PT of ewes. Our findings may provide the molecular basis for novel therapeutic strategies against this systemic metabolic disease in sheep.

Desorption experiments performed on four Cu-adsorbed palygorskites suggest that the leached Cu2+ ion originates at the surface and/or net-like interstice of the palygorskite fibres. The leached fraction, calculated from the quantities of adsorbed Cu2+ before and after desorption, is <1%. This may indicate that the majority of Cu is in inaccessible structural sites. X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared (FTIR) spectroscopy and electron spin resonance (ESR) were used to determine the mineralogical character of the Cu-adsorbed palygorskite. Two photoelectron lines at 932.5 and/or 933.7 eV in the narrow scan Cu 2p3/2 spectra show that Cu adsorbed on the surface of palygorskite is in the Cu+ and Cu2+ state. The stretching vibrations of the octahedral cation shift ~3–5 cm–1 towards a greater wavenumber in the FTIR spectra of Cu-adsorbed palygorskite. It can be deduced that the Cu2+ is trapped in the channel of the palygorskite structure. The ESR spectra of the palygorskite give g values of 2.34, 2.12, 2.08 and 2.05, suggesting that some Cu ions cannot be reached by H+. These results confirm that Cu is adsorbed by palygorskite via three possible mechanisms: (1) the Cu is adsorbed onto the surface or in a net-like interstice, and its oxidation states are +1 and +2; (2) Cu forms a complex ion – [Cu(H2O)4]2+ or [Cu(H2O)6]2+, and is trapped in the channel; or (3) Cu enters into the hexagonal channel of the tetrahedral sites or the unoccupied octahedral sites of palygorskite.

Increasing evidence has demonstrated that the environmental conditions experienced by parents can shape offspring phenotypes. Here, we examined the effects of the photoperiod and temperature experienced by parents on the incidence of diapause in their progeny in the cabbage beetle, Colaphellus bowringi, using three experiments. The first experiment examined parental diapause incidence under different photoperiods at 25°C and the incidence of diapause in progeny from both non-diapausing and diapausing parents under the same rearing conditions. The results revealed that the incidence of diapause among progeny was exactly opposite to that of their parents, i.e., higher parental diapause incidence led to lower progeny diapause incidence, showing a negative relationship in diapause incidence between the parental generation and the progeny generation. The incidence of diapause among progeny produced by diapausing parents was higher than that in progeny produced by non-diapausing parents. The second experiment examined parental diapause incidence at different temperatures under LD 12:12 and the incidence of diapause in progeny from both non-diapausing and diapausing parents under the same rearing conditions. Similarly, the incidence of diapause in progeny was also opposite to that of their parents. However, the incidence of diapause in progeny produced by non-diapausing parents was different from that in progeny produced by diapausing parents. In the third experiment, naturally diapausing adults were maintained at a constant temperature of 9, 28°C or the mean daily summer temperature of 27.84°C under continuous darkness for 3 months of dormancy. After dormancy, the progeny of these post-diapause parents were reared under different photoperiods at 25°C. The results showed that the incidence of diapause among progeny was higher when their parents experienced high temperatures than when they experienced low temperatures. All results demonstrate that the photoperiod and temperature experienced by parents may significantly affect the diapause incidence among progeny.

Foxtail millet (Setaria italica (L.) P. Beauv.) is a naturally stress-tolerant plant, a major reserve crop and a model for panicoid grasses. The recent completion of the S. italica genome facilitates identification and characterization of WRKY transcription factor family proteins that are important regulators of major plant processes, including growth, development and stress response. The present study identified 103 WRKY transcription factor-encoding genes in the S. italica genome. The genes were named SiWRKY1–SiWRKY103 according to their order on the chromosomes. A comprehensive expression analysis of SiWRKY genes among four different tissues was performed using publicly available RNA sequencing data. Eighty-four SiWRKY genes were more highly expressed in root tissue than in other tissues and nine genes were only expressed in roots. Additionally, real-time quantitative polymerase chain reaction was performed to comprehensively analyse the expression of all SiWRKY genes in response to dehydration. Results indicated that most SiWRKY genes (over 0.8) were up-regulated by drought stress. In conclusion, genome-wide identification and expression profiling of SiWRKY genes provided a set of candidates for cloning and functional analyses in plants’ response to drought stress.

This paper presents a novel analysis approach by considering multiple crack interaction in achieving FAA certification for durability and damage tolerance of exterior attachment installations on an aircraft fuselage according to FAA policy on Certification by Analysis-Supported-by-Test (CAST). Durability and damage tolerance evaluation of an aircraft component requires assessment of damage initiation and fatigue crack propagations under service loading, which consists of complex loading types, paths and variable amplitudes. Both simulation and service experience showed that multiple cracks developed in the fuselage skin and doublers that are made of wrought aluminum alloys. Progressive failure analysis (PFA) tool was used to simulate the fatigue damage initiation life using a scale-down stress-life property. A virtual crack closure technique (VCCT) was implemented to evaluate fatigue crack growth with interactions between cracks from different parts in a component, which preserves conservativeness. The fatigue crack growth data is obtained uniquely from an analytical extension of fatigue crack growth data of thin aluminum sheet. Fatigue crack growth analysis showed that only a few initiated cracks propagated steadily before a crack became visible under inspection, which was validated by comparison to service history. Eventually one crack became dominate in the fracturing process thereby setting an inspection time. Analysis also showed that fatigue damage state in the components at the designed operational life will not exceed the static safety requirements. Therefore, FAA accepted the damage tolerance analysis and the aircraft retained certification with no need for repair.

A new plant of Late Devonian (Famennian) age, Melvillipteris quadriseriata gen. et sp. nov., is reported from Melville Island, Nunavut, Canadian Arctic Archipelago. Main axes and two orders of lateral branches are recognized. The main axes are monopodial in habit, with a zigzag and/or upright appearance and dense adventitious roots attached on some internodes. First-order branches are inserted on the main axes in distichous pairs, showing a quadriseriate pattern (i.e. alternate pairs); they bear one or two sterile ultimate appendages on the proximal portions, and then distally bear alternate second-order branches. Second-order branches bear alternate ultimate appendages which may be fertile or sterile; the sterile ultimate appendages are composed of one or two successive dichotomies, terminating in oppositely recurved tips, and fertile appendages show an elaborate branching system. Each fertile appendage has an initial dichotomy forming two sister branches, each of which further divides three or four times to produce ultimate divisions terminated by sporangia. Two to four small fusiform sporangia are grouped in a truss which is supplied by penultimate division of the fertile appendage. The sporangia have a pointed tip and a longitudinal dehiscence. This new plant resembles other plants with a quadriseriate branching pattern (e.g. Rhacophyton Crépin, Cephalopteris Nathorst, Protocephalopteris Ananiev, Ellesmeris Hill, Scheckler & Basinger and Protopteridophyton Li & Hsü), and is assigned to the Rhacophytales. Its similarity to and divergence from the rhacophytaleans, cladoxylopsids and other related plants are discussed.

We derive zphot for sources in the entire (~0.4 deg2) H-HDF-N field with the EAzY code, based on PSF-matched broad-band (U band to IRAC 4.5 μm) photometry. Our catalog consists of a total of 131,678 sources. We find σNMAD = 0.029 for non-X-ray sources. We also classify each object as a star or galaxy through SED fitting. Furthermore, we match our catalog with the 2 Ms CDF-N main X-ray catalog. For the 462 matched non-stellar X-ray sources, we improve their zphot quality (σNMAD = 0.035) by adding three additional AGN templates. We make our photometry and zphot catalog publicly available.