Production Hierarchies in Sweden

I study the internal organization of firms using occupation data on workers in Swedish manufacturing firms. Firms with more layers are larger in size, in value added, and they pay higher wages. Firms are hierarchal in that lower layers have more workers and lower mean wage than higher layers. Adding layers is associated with increases in mean firm size/value added and decreases in mean firm wages (at pre-existing layers). The reverse holds for removing layers. This result also holds for layer by layer mean size and wages for a majority of pre-existing layers

Financial experts on the board: does it matter for the profitability and risk of the u.k. banking industry?

This paper explores the relation between board-level financial expertise, the profitability and the risk profile with panel data from the UK banking industry. The empirical findings document that collectively, financial experts have a positive influence on the performance outcomes of banks, they contribute to higher risks, especially in the case of large banks, while they improve the stock performance of the associated banks. Moreover, the results highlight that board-level qualified accountants have no statistical effect on that profitability, while such a positive link is established for the case of financial and banking professors, as well as for financial experts from other industries. Such findings imply that these two groups of professional financial experts may be easier adopted at group-level profits enhancement. Robustness checks confirm the results for all types of banking institutions, except those with a strong real-estate activity portfolio. Finally, certain commercial and/or policy implications of the results are reported.N/

Shafranov's virial theorem and magnetic plasma confinement

Shafranov's virial theorem implies that nontrivial magnetohydrodynamical equilibrium configurations must be supported by externally supplied currents. Here we extend the virial theorem to field theory, where it relates to Derrick's scaling argument on soliton stability. We then employ virial arguments to investigate a realistic field theory model of a two-component plasma, and conclude that stable localized solitons can exist in the bulk of a finite density plasma. These solitons entail a nontrivial electric field which implies that purely magnetohydrodynamical arguments are insufficient for describing stable, nontrivial structures within the bulk of a plasma.Comment: 9 pages no figure

RELEASE: A High-level Paradigm for Reliable Large-scale Server Software

Erlang is a functional language with a much-emulated model for building reliable distributed systems. This paper outlines the RELEASE project, and describes the progress in the first six months. The project aim is to scale the Erlang’s radical concurrency-oriented programming paradigm to build reliable general-purpose software, such as server-based systems, on massively parallel machines. Currently Erlang has inherently scalable computation and reliability models, but in practice scalability is constrained by aspects of the language and virtual machine. We are working at three levels to address these challenges: evolving the Erlang virtual machine so that it can work effectively on large scale multicore systems; evolving the language to Scalable Distributed (SD) Erlang; developing a scalable Erlang infrastructure to integrate multiple, heterogeneous clusters. We are also developing state of the art tools that allow programmers to understand the behaviour of massively parallel SD Erlang programs. We will demonstrate the effectiveness of the RELEASE approach using demonstrators and two large case studies on a Blue Gene

Tracking neural crest cell cycle progression in vivo

Analysis of cell cycle entry/exit and progression can provide fundamental insights into stem cell propagation, maintenance, and differentiation. The neural crest is a unique stem cell population in vertebrate embryos that undergoes long‐distance collective migration and differentiation into a wide variety of derivatives. Using traditional techniques such as immunohistochemistry to track cell cycle changes in such a dynamic population is challenging, as static time points provide an incomplete spatiotemporal picture. In contrast, the fluorescent, ubiquitination‐based cell cycle indicator (Fucci) system provides in vivo readouts of cell cycle progression and has been previously adapted for use in zebrafish. The most commonly used Fucci systems are ubiquitously expressed, making tracking of a specific cell population challenging. Therefore, we generated a transgenic zebrafish line, Tg(‐4.9sox10:mAG‐gmnn(1/100)‐2A‐mCherry‐cdt1(1/190)), in which the Fucci system is specifically expressed in delaminating and migrating neural crest cells. Here, we demonstrate validation of this new tool and its use in live high‐resolution tracking of cell cycle progression in the neural crest and derivative populations

Phenomenology with Wilson fermions using smeared sources

We investigate the use of two types of non-local (``smeared'') sources for quark propagators in quenched lattice QCD at $\beta=6.0$ using Wilson fermions at $\kappa=0.154$ and $0.155$. We present results for the hadron mass spectrum, meson decay constants, quark masses, the chiral condensate and the quark distribution amplitude of the pion. The use of smeared sources leads to a considerable improvement over previous results. We find a disturbing discrepancy between the baryon spectra obtained using Wuppertal and wall sources. We find good signals in the ratio of correlators used to calculate the quark mass and the chiral condensate and show that the extrapolation to the chiral limit is smooth.Comment: (revised), 57 pages (29 pages of PostScript in landscape mode, 765924 bytes

Tracking neural crest cell cycle progression in vivo

Analysis of cell cycle entry/exit and progression can provide fundamental insights into stem cell propagation, maintenance, and differentiation. The neural crest is a unique stem cell population in vertebrate embryos that undergoes long‐distance collective migration and differentiation into a wide variety of derivatives. Using traditional techniques such as immunohistochemistry to track cell cycle changes in such a dynamic population is challenging, as static time points provide an incomplete spatiotemporal picture. In contrast, the fluorescent, ubiquitination‐based cell cycle indicator (Fucci) system provides in vivo readouts of cell cycle progression and has been previously adapted for use in zebrafish. The most commonly used Fucci systems are ubiquitously expressed, making tracking of a specific cell population challenging. Therefore, we generated a transgenic zebrafish line, Tg(‐4.9sox10:mAG‐gmnn(1/100)‐2A‐mCherry‐cdt1(1/190)), in which the Fucci system is specifically expressed in delaminating and migrating neural crest cells. Here, we demonstrate validation of this new tool and its use in live high‐resolution tracking of cell cycle progression in the neural crest and derivative populations

The Extraction of Light Quark Masses From Sum Rule Analyses of Axial and Vector Current Ward Identities

We re-examine the use of sum rules in the extraction of light quark masses and discuss a number of potential problems with existing analyses. The most important issue is that of the overall normalization of the hadronic spectral functions should not be fixed by assuming complete resonance dominance of the continuum threshold region as it can overestimate the resonance contributions to spectral integrals by factors as large as $\sim 5$. The second important uncertainty comes from the assumed location, $s_0$, of the onset of duality with perturbative QCD, as the extracted quark masses depend very sensitively on this parameter. The assumption of duality and the requirement of positivity of $\rho_5(s)$ imposes very severe constraints on the shape of the relevant spectral function in the dual region, and leads to rigorous lower bounds for $m_u+m_d$ as a function of $s_0$. In the extractions of $m_s$ we find that the conventional choice of the value of $s_0$ is not physical. For a more reasonable choice of $s_0$ we are not able to find a solution that is stable with respect to variations of the Borel transform parameter. This problem can be overcome only if the hadronic spectral function is determined up to significantly larger values of $s$ than is currently possible. Finally, we also estimate the error associated with the convergence of perturbative QCD expressions used in the sum rule analyses. Our conclusion is that, taking all of these issues into account, the resulting sum rule estimates for both $m_u+m_d$ and $m_s$ could easily have uncertainties as large as a factor of 2.Comment: 28 pages. Published version. Modified "axis" source for figures also include

Light Quark Masses from Lattice QCD

We present estimates of the masses of light quarks using lattice data. Our main results are based on a global analysis of all the published data for Wilson, Sheikholeslami-Wohlert (clover), and staggered fermions, both in the quenched approximation and with $n_f=2$ dynamical flavors. We find that the values of masses with the various formulations agree after extrapolation to the continuum limit for the $n_f=0$ theory. Our best estimates, in the MSbar scheme at $\mu=2 GeV$, are \mbar=3.4 +- 0.4 +- 0.3 MeV and $m_s = 100 +- 21 +- 10 MeV$ in the quenched approximation. The $n_f=2$ results, \mbar = 2.7 +- 0.3 +- 0.3 MeV and $m_s = 68 +- 12 +- 7 MeV$, are preliminary. (A linear extrapolation in $n_f$ would further reduce these estimates for the physical case of three dynamical flavors.) These estimates are smaller than phenomenological estimates based on sum rules, but maintain the ratios predicted by chiral perturbation theory. The new results have a significant impact on the extraction of $\epsilon'/\epsilon$ from the Standard Model. Using the same lattice data we estimate the quark condensate using the Gell-Mann-Oakes-Renner relation. Again the three formulations give consistent results after extrapolation to $a=0$, and the value turns out to be correspondingly larger, roughly preserving m_s \vev{\bar \psi \psi}.Comment: 32 pages. Package submitted in uufiles format: unpack and tex paper.tex. Modified "axis" source for figures also included. Latex2e document. Uncomment hyperref if available. This is the final published versio

Financial Development, Financial Constraints, and the Volatility of Industrial Output

More financially developed countries show lower volatility of industrial output. Volatility is particularly reduced in industries that are more financially dependent. Most of the reduction is in idiosyncratic volatility. Systematic volatility is reduced less strongly, implying that industries are more closely correlated with GDP in more financially developed countries. At the firm level, short-term debt is negatively correlated with output as financial development increases, suggesting that debt is used in a countercyclical way to stabilize production. The results indicate that financial development relaxes financial constraints mainly to smooth negative cashflow shocks