Intertemporal choices involve tradeoffs between outcomes that occur at different times. Most of the research has used pure gains tasks and the discount rates yielding from those tasks to explain and predict real-world behaviors and consequences. However, real decisions are often more complex and involve mixed outcomes (e.g., sooner-gain and later-loss or sooner-loss and later-gain). No study has used mixed gain-loss intertemporal tradeoff tasks to explain and predict real-world behaviors and consequences, and studies involving such tasks are also scarce. Considering that tasks involving a combination of gains and losses may yield different discount rates and that existing pure gains tasks do not explain or predict real-world outcomes well, this study conducted two experiments to compare the discount rates of mixed gain-loss intertemporal tradeoffs with those of pure gains or pure losses (Experiment 1) and to examine whether these tasks predicted different real-world behaviors and consequences (Experiment 2). Experiment 1 suggests that the discount rate ordering of the four tasks was, from highest to lowest, pure gains, sooner-loss and later-gain, pure losses, and sooner-gain and later-loss. Experiment 2 indicates that the evidence supporting the claim that the discount rates of the four tasks were related to different real-world behaviors and consequences was insufficient.

Mammal sex determination depends on whether the X sperm or Y sperm binds to the oocyte during fertilization. If the X sperm joins in oocyte, the offspring will be female, if the Y sperm fertilizes, the offspring will be male. Livestock sex control technology has tremendous value for livestock breeding as it can increase the proportion of female offspring and improve the efficiency of livestock production. This review discusses the detailed differences between mammalian X and Y sperm with respect to their morphology, size, and motility in the reproductive tract and in in vitro conditions, as well as ’omics analysis results. Moreover, research progress in mammalian sex control technology has been summarized.

To code-switch or not to code-switch? This is a dilemma for many bilingual language teachers. In this study, the influence of teachers’ CS on bilingual children's language and cognitive development is explored within heritage language (HL) classes in Singapore. Specifically, the relationship between children's language output, vocabulary development, and cognitive flexibility to teachers’ classroom CS behavior, is examined within 20 preschool HL classrooms (10 Mandarin, 6 Malay, and 4 Tamil). Teachers’ and children's utterances were recorded, transcribed, and analyzed for CS frequency and type (i.e., inter-sentential, intra-sentential). 173 students were assessed with receptive vocabulary and dimensional card sort tasks, and their vocabulary and cognitive switching scores assessed using correlational and mixed effects analyses. Results show that inter-sentential and intra-sentential CS frequency is positively and significantly related to children's intra-sentential CS frequency. Overall, findings revealed that teachers code-switched habitually more often than for instructional purposes. Neither inter-sentential nor intra-sentential CS was significantly related to children's development in HL vocabulary, and intra-sentential CS was found to positively and significantly relate to children's growth in cognitive flexibility. These findings reveal the multi-faceted impact of teacher's CS on children's early development.

Many shorebird populations are in decline along the East Asian-Australasian Flyway. The rapid loss of coastal wetlands in the Yellow Sea, which provide critical stop-over sites during migration, is believed to be the cause of the alarming trends. The Yalu Jiang coastal wetland, a protected area in the north Yellow Sea, supports the largest known migratory staging populations of Bar-tailed Godwits Limosa lapponica (menzbieri and baueri subspecies) and Great Knots Calidris tenuirostris. Monitoring of the macrozoobenthos food for these shorebirds from 2011 to 2016 showed declines of over 99% in the densities of the bivalve Potamocorbula laevis, the major food here for both Bar-tailed Godwits and Great Knots. The loss of the bivalve might be caused by any combination of, but not limited to: (1) change in hydrological conditions and sediment composition due to nearby port construction, (2) run-off of agrochemicals from the extensive shoreline sea cucumber farms, and (3) parasitic infection. Surprisingly, the numbers of birds using the Yalu Jiang coastal wetland remained stable during the study period, except for the subspecies of Bar-tailed Godwit L. l. menzbieri, which exhibited a 91% decline in peak numbers. The lack of an overall decline in the number of bird days in Great Knots and in the peak numbers of L. l. baueri, also given the published simultaneous decreases in their annual survival, implies a lack of alternative habitats that birds could relocate to. This study highlights that food declines at staging sites could be an overlooked but important factor causing population declines of shorebirds along the Flyway. Maintaining the quality of protected staging sites is as important in shorebird conservation as is the safeguarding of staging sites from land claim. Meanwhile, it calls for immediate action to restore the food base for these beleaguered migrant shorebirds at Yalu Jiang coastal wetland.

In this paper, numerical simulations of solid particle erosion phenomena on H-type finned circular/elliptic tube surface, which is of great significance to the antiwear design of heat exchanger, are presented. The Eulerian-Lagrangian approach is applied to simulate the dilute gas-solid flow through H-type finned circular/elliptic tubes. A semi-empirical model is adopted to predict the erosion rate. The dynamics behavior of the entrained solid particles in the flow is presented. The geometry of eroded tube surface is changed with the predicted erosion which is taken into account by a UDF and the flow field is re-solved for the eroded tube surface at every time step. The influences of ten parameters (the tube bundle arrangement, particle size, particle concentration, fluid Reynolds number, fin thickness, fin pitch, fin length, fin width, slit width and the transverse tube pitch) on the maximum erosion depth of the H-type circular/elliptic finned tube surface are investigated. Using H-type finned elliptic tube surface can effectively reduce the erosion rate of tube surface comparedwith that using H-type finned circular tube surface. The erosion in in-line arrangement is less severe than that in staggered arrangement. With the increase of particle size, particle concentration and the fluid Reynolds number, the erosion rate of the tube surface rises. The numerically predicted effect of Reynolds number is in good agreement with previous test data. Among the six geometry parameters, the most influential parameter is the transverse tube pitch.

To study the formation mechanism and stability of the phase in the interface of tungsten carbide particles reinforced iron matrix composites, the composites were fabricated by spark plasma sintering (SPS) technique and combined with first-principles calculation. It was found that Fe3W3C compound was stable from the perspective of both thermodynamics and mechanical properties based on our calculations. Interfacial reaction product of tungsten carbide particles reinforced iron matrix composites was M6C. Experimental results indicated that the samples prepared by SPS did not appear interfacial reaction zone, while, interfacial reaction zone appeared for the remelted samples. With the increasing remelting temperature, the width of the interface reaction zone increased because the mutual diffusion occurred at the interface between tungsten carbide particles and matrix. Its formation mechanism was 3Fe + 3/2W2C → Fe3W3C + 1/2C. Our research might provide a theoretical guidance in controlling the interface of tungsten carbide particles reinforced iron matrix composites.

Anatase nitrogen and fluoride codoped TiO2 sol (N–F–TiO2) catalysts were fabricated by a modified sol-gel hydrothermal method, using tetrabutyl titanate as precursor. The microstructure and morphology of sol sample were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible dielectric relaxation spectroscopy (UV-VIS-DRS), x-ray photoelectron spectroscopy (XPS), etc. It was shown that N–F–TiO2 particles in sol were partly crystallized to anatase structure and dispersed in the aqueous medium homogeneously. The average particle size was ∼12.0 nm calculated from XRD patterns, and the particle size distribution was narrow. It was noteworthy that the N–F-codoped TiO2 sol particles showed strong visible-light response and high photocatalytic activity for formaldehyde degradation under irradiation by visible light (400–500 nm); we suggested that it may result from the generation of additional band of N 2p in the forbidden band and the synergetic effect of codoping nitrogen and fluorine.

Protein kinase C (PKC) is a family of Ser/Thr protein kinase widely distributed in eukaryotes. There is evidence that PKC plays key roles in the meiotic maturation and activation of mammalian oocytes. However, the mechanism of PKC's actions and the PKC isoforms responsible for these actions are poorly understood. In this study, we reveal in mouse eggs and early embryos: (1) the effects of PKC on the meiotic and mitotic cell cycle progression during oocyte maturation, egg activation and embryonic cleavages; (2) the functional importance of classical PKC subclasses in these processes; and (3) the subcellular localization of the PKCα isoform during development from GV stage oocytes to the blastocyst stage embryos. The results indicate that the PKC activator phorbol 12-myristate 13-acetate (PMA) inhibits the meiotic resumption of cumulus-free mouse oocytes by a mechanism dependent not only on classical PKC activity but also on other PKC isoforms. PKC activation after germinal vesicle breakdown leads to the inhibition of mitogen-activated protein kinase phosphorylation and the arrest of cell cycle at MI stage. The second polar body emission and the cleavages of early embryos are blocked after prolonged PKC activation. The subcellular localization of PKCα isoform in mouse oocytes and embryos is developmental-stage associated. All these results suggest that PKC has multiple functional roles in the cell cycle progression of mouse oocytes and embryos.

Syntheses of Al-based metastable alloys from powder mixtures of elemental Al and amorphous Fe78Si12B10 [x at. % Al + (100 — x) at. % (Fe78Si12B10)] alloy by mechanical milling (MM) using a planetary ball mill are investigated. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) are used to characterize their structure during the MM process. For the powder mixture with low content of Al (x = 75, 82), fully amorphous material can be obtained by MM, while for the milled product with a high content of Al (x = 90), nanocrystalline Al and amorphous phases are obtained. During the initial milling stage, the Al atoms are dissolved into the amorphous Fe78Si12B10 matrix by heavy deformation. Consequently, the Al-enriched homogeneous amorphous alloys are produced with the disappearance or shrinkage of diffraction peaks of Al in the XRD pattern. Further milling of the powder mixture with 75 at. % Al results in the crystallization of amorphous phase and the formation of nanocrystalline Al3Fe type phase. The crystallization products of all as-milled samples are very similar, composed of Al13Fe4 and AlFe3 phases. It is suggested that the kinetics of nucleation and growth favor the formation of amorphous phase due to the existence of amorphous phase initially. The amorphization reaction by mechanical milling is diffusion process, but defects and strain also play an important role.