Sticky Wages. Evidence from Quarterly Microeconomic Data.

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.

Coefficient of Restitution as a Fluctuating Quantity

The coefficient of restitution of a spherical particle in contact with a flat plate is investigated as a function of the impact velocity. As an experimental observation we notice non-trivial (non-Gaussian) fluctuations of the measured values. For a fixed impact velocity, the probability density of the coefficient of restitution, $p(\epsilon)$, is formed by two exponential functions (one increasing, one decreasing) of different slope. This behavior may be explained by a certain roughness of the particle which leads to energy transfer between the linear and rotational degrees of freedom.Comment: 4 pages, 4 figure

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

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 $\lambda_{\rm d}=\sqrt[4]{\hbar c/\rho_{\rm d}}\approx 85 \mu$m. We find with 95% confidence that the inverse-square law holds ($|\alpha| \leq 1$) down to a length scale $\lambda = 56 \mu$m and that an extra dimension must have a size $R \leq 44 \mu$m.Comment: 4 pages, 6 figure

Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction

In the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphid Metopeurum fuscoviride, a specialist on tansy Tanacetum vulgare, and its specialist primary hymenopterous parasitoid Lysiphlebus hirticornis, both of which are characterized by multivoltine life histories and a classic metapopulation structure. Samples of the aphid host and the parasitoid were collected from eight sites in and around Jena, Germany, where both insect species co-occur, and then were genotyped using suites of polymorphic microsatellite markers. The host aphid was greatly differentiated in terms of its spatial population genetic patterning, while the parasitoid was, in comparison, only moderately differentiated. There was a positive Mantel test correlation between pairwise shared allele distance (DAS) of the host and parasitoid, i.e. if host subpopulation samples were more similar between two particular sites, so were the parasitoid subpopulation samples. We argue that while the differences in the levels of genetic differentiation are due to the differences in the biology of the species, the correlations between host and parasitoid are indicative of dependence of the parasitoid population structure on that of its aphid host. The parasitoid is genetically tracking behind the aphid host, as can be expected in a classic metapopulation structure where host persistence depends on a delay between host and parasitoid colonization of the patch. The results may also have relevance to the Red Queen hypothesis, whereupon in the ‘arms race’ between parasitoid and its host, the latter ‘attempts’ to evolve away from the former

Measurement of Linear Stark Interference in 199Hg

We present measurements of Stark interference in the 6$^1S_0$ $\rightarrow$ 6$^3P_1$ transition in $^{199}$Hg, a process whereby a static electric field $E$ mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to $E$-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, $a_{SI}$ = $(a_{M1} + a_{E2})$ = (5.8 $\pm$ 1.5)$\times 10^{-9}$ (kV/cm)$^{-1}$, agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the $^{199}$Hg EDM search apparatus to resolve non-trivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.Comment: 4 pages, 4 figures, 1 table; revised in response to reviewer comment

Spin-Dependent Macroscopic Forces from New Particle Exchange

Long-range forces between macroscopic objects are mediated by light particles that interact with the electrons or nucleons, and include spin-dependent static components as well as spin- and velocity-dependent components. We parametrize the long-range potential between two fermions assuming rotational invariance, and find 16 different components. Applying this result to electrically neutral objects, we show that the macroscopic potential depends on 72 measurable parameters. We then derive the potential induced by the exchange of a new gauge boson or spinless particle, and compare the limits set by measurements of macroscopic forces to the astrophysical limits on the couplings of these particles.Comment: 37 page

Editorial

Welcome to the second edition of the International Journal for Researcher Development. In this issue, we are pleased to include an in-depth study on the professionality of researchers per se. In her article, ‘Developing research capacity in the social sciences: a professionality-based model’ Linda Evans draws attention to the importance of both developing a research culture and developing researchers themselves. She suggests that leadership in research is failing to achieve the development of institutional research capacity to an acceptable standard whilst researchers themselves are unaware of the necessity to develop continually. In our next article, Fowler and colleagues present evidence from a recent study as to the factors that are necessary to facilitate the building of research capacity in the UK. In their article, ‘Building research capacity across the UK: evidence from recent initiatives in England, Scotland and Wales’ they recommend more explicit institutional commitment to the professional development of research staff and suggest that this should include the facilitation of mentoring relationships between more and less experienced researchers. The paper by Pitcher and Akerlind provides an international slant by presenting results of a novel study using metaphor analysis across several Australian Universities. This enabled conceptions of research by researchers to be categorized. Finally, we include a report on discussions based around evaluating developmental activities for researchers in higher education. In the UK, Roberts funding came on-line in 2002 to support the development of skills training for post-graduate researchers – to assist their employability. That tranche of funding is nearing its end and universities across the UK are now having to evaluate the worth of the products of that funding and how to fund it, if at all, in the future. The Gough report on the discussions surrounding the development of an evaluation approach make interesting reading

Improved limit on the permanent electric dipole moment of 199Hg

We report the results of a new experimental search for a permanent electric dipole moment of 199Hg utilizing a stack of four vapor cells. We find d(199Hg) = (0.49 \pm 1.29_stat \pm 0.76_syst) x 10^{-29} e cm, and interpret this as a new upper bound, |d(199Hg)| < 3.1 x 10^{-29} e cm (95% C.L.). This result improves our previous 199Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the standard model.Comment: 4 pages, 4 figures. additional reference, minor edits in response to reviewer comment

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

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