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Mutations, such as single nucleotide polymorphisms ( SNPs), in the 5′-flanking and micro RNA (mi RNA) regulatory regions may result in altered gene expression levels and cause diseases. Alpha-2-macroglobulin ( A2 M) has the function of binding host or foreign peptides and particles, and thereby serves as a defense barrier against pathogens in the plasma and tissues of animals. To investigate the functional markers of the A2 M gene associated with mastitis, the promoter was characterized and SNPs that affect promoter activity or binding affinity with the target mi RNA were identified using the luciferase reporter assay and real-time quantitative PCR method. Results showed that the core promoter of A2 M was found between the bases g.-2641 and g.-2479. Four novel SNPs (g.-724A>G, g.-665G>A, g.-535C>G and g.-520_-519ins A) in the promoter region were completely linked. The activity of the mutant haplotype ( GAGA) increased by 177% compared with that of the wild haplotype ( AGC-). Bta-mi R-2898 was upregulated by 6.25-fold in the mammary gland tissues of mastitis-infected cows compared with that of the healthy cows. One SNP (c.4659_4661del C) located in the 3′-untranslated region of the A2 M gene may affect the binding affinity with the target bta-mi R-2898. Five SNPs exhibited tight linkage. Association analysis showed that the milk somatic cell score for cows with the mutant haplotype ( GAGA-) was lower than that for cows with the wild haplotype. Thus, the mutant type can be used as a potential functional marker for a mastitis resistance breeding program in dairy cows. Our findings provided the molecular basis for A2 M transcriptional and post-transcriptional regulations. A close relationship between regulatory mutations and mastitis susceptibility of cows also was established. [ABSTRACT FROM AUTHOR]

Gonad differentiation in male zebrafish involves a transformation from a ‘juvenile ovary’ to testis. In our study, this phenomenon was analysed using a stable transgenic line ( vas::egfp) created by Krovel & Olsen (Mechanisms of Development, 116: 141–150, 2002). Our data obtained by histological and immunohistochemical methods show that the onset of enhanced green fluorescent protein (EGFP) expression marks the conversion of the bipotential gonad into a ‘juvenile ovary’, and its subsequent decrease in the males indicates transformation into a testis. Furthermore, during the ‘juvenile ovary’ stage, a high level of variation was observed among individuals not only in the starting point and duration of EGFP expression but also in its intensity. The intensity of reporter expression in the males ranged from a high level of expression – similar to that observed in females – to invisible expression and correlated with the number of oocytes, the shape of ‘juvenile ovary’ and its lumen. Therefore, the authors conclude that although all males develop ‘juvenile ovaries’, they differ vastly in the extent of their commitment toward femaleness during this stage before testis differentiation. The differentiating zebrafish testis shows morphological features similar to those of the transforming gonad of protogynous hermaphrodites, and therefore, it could be a good model for the study of the process of female-to-male sex change in adult teleosts. [ABSTRACT FROM AUTHOR]

We investigated the potential impact of three opiine tephritid fruit fly parasitoids:Fopius arisanus(Sonan),Fopius caudatus(Szépligeti) andFopius ceratitivorusWharton, on the non-target native Hawaiian tephritid,Trupanea dubautiae(Bryan), infesting flowerheads of the endemic Asteraceae shrubDubautia raillardioidesHillebrand. The three species are the only known opiine fruit fly parasitoids that attack host eggs (but occasionally attack first instars).F. arisanus, which originated in southeast Asia, is now widely established in Hawaii and elsewhere in the world, while the other two are African species currently in quarantine in Hawaii. In the laboratory, field-collected flowerheads ofD. raillardioidescontainingT. dubautiaeeggs and first instar larvae were exposed to naïve female wasps of each of the threeFopiusspecies in the absence (no-choice test) or presence (choice test) of papaya fruit infested with eggs of the Mediterranean fruit flyCeratitis capitata(Wiedemann), the parasitoids’ normal host. All threeFopiusspecies visited the papaya fruit much more often than the flowerheads, and displayed normal ovipositional responses (probing and stinging) on the fruit in the choice test. None of the three parasitoid species showed ovipositional responses to flowerheads in either choice or no-choice tests. As a result, not a singleT. dubautiaeegg or larva was attacked by any of the three parasitoids, indicating that these parasitoids of pest tephritids are unable to recognize the microhabitats of flowerhead-feeding tephritids. The results suggest minimal risk of non-target impact in these biological control agents. [ABSTRACT FROM AUTHOR]

This paper aims at proposing a new fatigue life estimation model that is preferably adapted to welded joints subjected to multiaxial loading. First, a mesh-size insensitive structural stress is defined that enables to characterize the stress concentration effect appropriately. Second, the multiaxial stress state and loading path influence are taken into account in the lifetime prediction model by adopting a suitable critical plane method, originally proposed by Carpinteri and co-authors. Experimental verification is conducted for a given welded joint geometry under different loading conditions, including uniaxial, torsional and multiaxial loads. The reliability and effectiveness of the new method are validated through substantive fatigue testing data. [ABSTRACT FROM AUTHOR]

1 The egg-prepupal parasitoid Fopius arisanus (Hymenoptera: Braconidae) was evaluated in quarantine facilities as a potential biological control agent for the olive fruit fly Bactrocera oleae (Diptera: Tephritidae) in California, U.S.A. 2 Nontarget testing of two weed biological control agents confirmed that F. arisanus will not attack Tephritidae that feed in inflorescences or galls. It may, however, pose risks to native Tephritidae that feed in fruit. 3 Females preferentially oviposited in eggs, although first-instar B. oleae were also attacked. Low lifetime reproductive potential and high rates of direct mortality inflicted on host eggs indicate that rearing on B. oleae may prove difficult. 4 In multiparasitized B. oleae, F. arisanus prevailed in competition against two species of larval–pupal parasitoids, Diachasmimorpha kraussii and Psyttalia concolor (both Hymenoptera: Braconidae). 5 The broad host-range of F. arisanus with respect to fruit-feeding Tephritidae may preclude its introduction to California, as may its low fecundity and its intrinsic competitive superiority over larva l–pupal parasitoids, which include specialists on B. oleae that are currently being introduced to California. High rates of direct mortality, however, point to potential uses in augmentative biological control. Whether or not F. arisanus is released in California, its biology as a parasitoid of B. oleae has been little studied to date and the results herein may be applied in other regions worldwide where B. oleae is a problem. [ABSTRACT FROM AUTHOR]

Kinetic‐scale magnetic dips (KSMDs), with a significant depression in magnetic field strength, and scale length close to and less than one proton gyroradius, were reported in the turbulent plasmas both in recent observation and numerical simulation studies. These KSMDs likely play important roles in energy conversion and dissipation. In this study, we present observations of the KSMDs that are labeled whistler mode waves, electrostatic solitary waves, and electron cyclotron waves in the magnetosheath. The observations suggest that electron temperature anisotropy or beams within KSMD structures provide free energy to generate these waves. In addition, the occurrence rates of the waves are higher in the center of the magnetic dips than at their edges, implying that the KSMDs might be the origin of various kinds of waves. We suggest that the KSMDs could provide favorable conditions for the generation of waves and transfer energy to the waves in turbulent magnetosheath plasmas. Plain Language Summary: The Earth's magnetosheath is a turbulent plasma environment where energy conversion, particle acceleration, and mass and momentum transport take place. Many of these key processes involve kinetic‐scale physics. However, in‐depth studies from previous missions are limited by their lower spacecraft data resolution. The recent Magnetospheric Multiscale (MMS) mission provides us with a large amount of high‐temporal cadence data for studying kinetic‐scale physics in the magnetosheath. In this study, we report whistler mode waves, electrostatic solitary waves and electron cyclotron waves within kinetic‐scale magnetic dips (KSMDs) that can be generated in the turbulent magnetosheath. These waves could be excited by electron temperature anisotropy or beams. As is well known, plasma waves are important processes in converting energy, accelerating and scattering electrons and ions, and modifying the distributions of charged particles. If plasma instabilities develop within the KSMDs, the resulting waves could absorb free energy from plasma particles and may propagate out of the KSMDs. Thus, our discoveries could significantly advance the understanding of energy conversion and dissipation for kinetic‐scale turbulence. This study provides a new reference not only for observations in space physics but also for related basic plasma theories and numerical simulations. Key Points: MMS observations reveal KSMDs coupled with whistler mode waves, electrostatic solitary waves, and electron cyclotron wavesThese waves are excited by different plasma distributions, and the ESWs could affect the electron distributions in kinetic scaleStatistical results indicate that the KSMDs in the magnetosheath are a possible origin for various kinds of waves [ABSTRACT FROM AUTHOR]

In this paper, the influence of the residual stress on the fatigue performance of a welded structure under multiaxial loading modes is studied. First, the local stress state at weld toe is modified via introduction of the residual stress, and a new fatigue life estimation model considering the effect of the residual stress is established by modifying our recently proposed critical plane method. Second, the basic theory and procedure of the finite element simulation on the calculation of the welding residual stress are presented. Finally, a numerical simulation of an aluminum alloy flange-to-tube welding process is conducted, and the calculated residual stress is verified with X-ray diffraction measurement. Furthermore, the performance of the proposed fatigue life estimation model is verified by the experimental data obtained in the fatigue test under different loading modes. It confirms that the consideration of the residual stress is important, especially under the out-of-phase loading mode. [ABSTRACT FROM AUTHOR]

Abstract: The sudden enhancements of magnetic strength, named magnetic peaks (MPs), are often observed in the magnetosheath of magnetized planets. They are usually identified as flux ropes (FRs) or magnetic mirror mode structures. Previous studies of MPs are mostly on the magnetohydrodynamics (MHD) scale. In this study, an electron scale MP is reported in the Earth magnetosheath. We present a typical case with a scale of ~7 electron gyroradii and a duration of ~0.18 s. A strong magnetic disturbance and associated electrical current are detected. Electron vortex is found perpendicular to the magnetic field line and is self‐consist with the peak. We use multipoint spacecraft techniques to determine the propagation velocity of the MP structure and find that the magnetic peak does propagate relative to the plasma (ion) flow. This is very different from the magnetic mirror mode that does not propagate relative to the plasma flow. Furthermore, we developed an efficient method that can effectively distinguish “magnetic bottle like” and “FRs like” structures. The MP presented in this study is identified as magnetic bottle like type. The mechanism to generate the electron scale magnetic bottle like structure is still unclear, suggesting that new theory needs to be developed to understand such small‐scale phenomena. [ABSTRACT FROM AUTHOR]

This paper proposes a novel analysis method of stochastic crack trajectory based on a dimension reduction approach. The developed method allows efficiently estimating the statistical moments, probability density function and cumulative distribution function of the crack trajectory for cracked elastic structures considering the randomness of the loads, material properties and crack geometries. First, the traditional dimension reduction method is extended to calculate the first four moments of the crack trajectory, in which the responses are eigenvectors rather than scalars. Then the probability density function and cumulative distribution function of the crack trajectory can be obtained using the maximum entropy principle constrained by the calculated moments. Finally, the simulation of the crack propagation paths is realized by using the scaled boundary finite element method. The proposed method is well validated by four numerical examples performed on varied cracked structures. It is demonstrated that this method outperforms the Monte Carlo simulation in terms of computational efficiency, and in the meanwhile, it has an acceptable computational accuracy. [ABSTRACT FROM AUTHOR]