3,047 research outputs found

    Sticky Wages. Evidence from Quarterly Microeconomic Data.

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    This paper documents nominal wage stickiness using an original quarterly firm-level dataset. We use the ACEMO survey, which reports the base wage for up to 12 employee categories in French firms over the period 1998 to 2005, and obtain the following main results. First, the quarterly frequency of wage change is around 35 percent. Second, there is some downward rigidity in the base wage. Third, wage changes are mainly synchronized within firms but to a large extent staggered across .firms. Fourth, standard Calvo or Taylor schemes fail to match micro wage adjustment patterns, but fixed duration "Taylor-like" wage contracts are observed for a minority of firms. Based on a two-thresholds sample selection model, we perform an econometric analysis of wage changes. Our results suggest that the timing of wage adjustments is not state-dependent, and are consistent with existence of predetermined of wage changes. They also suggest that both backward- and forward-looking behavior is relevant in wage setting.Wage stickiness ; Wage predetermination.

    Lorentz Violation and Synchrotron Radiation

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    We consider the radiation emitted by an ultrarelativistic charged particle moving in a magnetic field, in the presence of an additional Lorentz-violating interaction. In contrast with prior work, we treat a form of Lorentz violation that is represented by a renormalizable operator. Neglecting the radiative reaction force, the particle's trajectory can be determined exactly. The resulting orbit is generally noncircular and does not lie in the place perpendicular to the magnetic field. We do not consider any Lorentz violation in the electromagnetic sector, so the radiation from the accelerated charge can be determined by standard means, and the radiation spectrum will exhibit a Lorentz-violating directional dependence. Using data on emission from the Crab nebula, we can set a bound on a particular combination of Lorentz-violating coefficients at the 6×10206\times10^{-20} level.Comment: 14 page

    Velocity in Lorentz-Violating Fermion Theories

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    We consider the role of the velocity in Lorentz-violating fermionic quantum theory, especially emphasizing the nonrelativistic regime. Information about the velocity will be important for the kinematical analysis of scattering and other problems. Working within the minimal standard model extension, we derive new expressions for the velocity. We find that generic momentum and spin eigenstates may not have well-defined velocities. We also demonstrate how several different techniques may be used to shed light on different aspects of the problem. A relativistic operator analysis allows us to study the behavior of the Lorentz-violating Zitterbewegung. Alternatively, by studying the time evolution of Gaussian wave packets, we find that there are Lorentz-violating modifications to the wave packet spreading and the spin structure of the wave function.Comment: 24 page

    Polynucleotide encoding a gene conferring resistance to Bacillus thuringiensis toxins

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    Nucleic acid (DNA) probes are provided which will specifically identify a gene for resistance of Bt in insect populations. Sequences are identified associated with the onset of resistance to Bacillus thuringiensis toxins. The sequences are used as probes to monitor the presence of acquired insect resistance associated with transgenic crops

    Approaches to land snail shell bead manufacture in the Early Holocene of Malawi

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    Shell disc beads are important archeological indicators of social communication and exchange networks. There has been substantial research on ostrich eggshell (OES) beads, but little is known about the manufacture or chronology of similar beads from land snail shells (LSS). LSS beads are associated with Holocene hunter-gatherers in Africa, though direct dates are limited to the Iron Age, and there are no images or descriptions of the manufacturing sequence. Here, we combine experimental and archeological data to resolve the chronology, operational chains, and material properties of LSS bead manufacture. We then recommend and apply a modified OES production sequence to three Later Stone Age assemblages from the Kasitu Valley of northern Malawi (Hora 1, Mazinga 1, and Kadawonda 1). At these sites, LSS shows an unexpectedly high proportion of Pathway 2 manufacture (disc shaping prior to perforation), in direct contrast with known OES bead manufacture. Application of red color occurred at all stages of manufacture, albeit inconsistently. Production of finished beads involved substantial removal of material from preforms to create the final product. Finally, we report the earliest evidence for LSS bead manufacture with two directly dated preforms (~ 9500 cal BP), showing that the origins of LSS beadmaking do precede the Iron Age.Introduction Background and previous research - The problem of land snail disc beads - Land snail shell versus ostrich eggshell Materials and methods - Experimental methods -- Breakage -- Shaping -- Drilling -- Pigments - Archeological samples -- Site descriptions -- Recovery protocols -- Sorting, data collection, and analysis -- Dating Results - Experimental results -- Breakage -- Shaping -- Drilling -- Production stages specific to LSS -- Application of pigments - Archeological results -- Assemblage description -- Manufacturing chains -- Dating Discussion Conclusion

    Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale

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    We conducted three torsion-balance experiments to test the gravitational inverse-square law at separations between 9.53 mm and 55 micrometers, probing distances less than the dark-energy length scale λd=c/ρd485μ\lambda_{\rm d}=\sqrt[4]{\hbar c/\rho_{\rm d}}\approx 85 \mum. We find with 95% confidence that the inverse-square law holds (α1|\alpha| \leq 1) down to a length scale λ=56μ\lambda = 56 \mum and that an extra dimension must have a size R44μR \leq 44 \mum.Comment: 4 pages, 6 figure

    Development of a LAMP-based molecular species diagnosis method for four major agricultural pests in the genus Spodoptera (Lepidoptera: Noctuidae)

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    SIMPLE SUMMARY: Four major Spodoptera pests, S. exigua, S. frugiperda, S. litura, and S. littoralis, are widely distributed polyphagous pests affecting various crops. Despite different distribution areas, these four species cause serious damage to agriculture worldwide. As these species are morphologically similar at the larval stage, diagnostic methods have been developed and utilized for their identification. Here, we developed a loop-mediated isothermal amplification (LAMP) assay for rapid and effective species diagnosis, along with PCR, to identify Korean field-collected or overseas samples. The optimal conditions for the LAMP assay were 61 °C for 60 min with four LAMP primers. Additional loop primers increased the amplification efficiency in S. exigua, whereas increased non-specific amplification was found in other species. A broad range of DNA concentrations was observed in the LAMP assay, and the minimum detectable DNA concentration was 1 pg. The DNA release method for LAMP involved incubation of larval or adult tissue samples for 5 min at 95 °C, without a DNA extraction step. Considering the gradual diversification invasive pest incidence, this simple and accurate LAMP assay can be used for intensive field monitoring of invasive pests and integrated management of these species. ABSTRACT: Molecular-based species identification tools are helpful to identify tiny insect and lepidopteran pests that show morphological similarities in the larval stage and are essential for quarantine as well as agricultural research. Here, we focused on four major Spodoptera pests: S. exigua, S. frugiperda, S. litura, and S. littoralis. S. exigua and S. litura mitochondrial genome sequences were newly identified and species-specific sequence regions were identified in the cytochrome c oxidase subunit II and III regions. Species primers were designed and applied in loop-mediated isothermal amplification (LAMP) and PCR to identify Korean field-collected or overseas samples. The optimal incubation conditions for LAMP were 61 °C for 60 min with four LAMP primers. Additional loop primers increased the amplification efficiency for S. exigua, and the nonspecific amplification for other species. The LAMP assay could detect a wide range of DNA concentrations, with the range 1 ng–1 pg in dependence of four LAMP primers. The DNA-releasing technique, without DNA extraction, in the LAMP assay involved larval or adult tissue sample incubation at 95 °C for 5 min. The entire process takes approximately 70 min. This new molecular diagnostic method is simple and accurate, with application in the field and laboratory and for monitoring and ecological studies
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