A Revised Geometry for the Magnetic Wind of theta^1 Orionis C

Theta^1 Ori is thought to be a hot analog of Bp variables because its optical and UV line and X-ray continuum fluxes modulate regularly over the magnetic/rotational period. A flattened magnetosphere surrounding co-rotates with these stars, producing a periodic modulation of emission and absorption components of the UV resonance lines, as well as of optical H and He lines. In this paper we examine these modulations in detail and point out that the far-blue and near-red wings of C IV and N V resonance lines exhibit anticorrelated modulations, causing mild flux elevations at moderate redshifts at edge-on phase (phi=0.5). However, the lines do not exhibit rest-frame absorption features, the usual signatures of cool static disks surrounding Bp stars. We suggest that this behavior can be explained by the existence of two geometrically distinct wind regions separated by the local magnetic Alfven radius. Wind streams emerging outside this point are forced outward by radiative forces and eventually expand outward radially to infinity - this matter produces the far-blue wing absorptions at phi=0.5. Interior streams follow closed loops and collide at the magnetic equator with counterstreams. There they coalesce and fall back to the star along their original field lines - these are responsible for mild emissions at this same phase. The rapid circulation of the interior wind component back to the star is responsible for the absence of static disk features.Comment: 7 figure

Who Should Pay for Certification?

Who does, and who should initiate costly certification by a third party under asymmetric quality information, the buyer or the seller? Our answer - the seller - follows from a nontrivial analysis revealing a clear intuition. Buyer-induced certification acts as an inspection device, seller-induced certification as a signalling device. Seller-induced certification maximizes the certifier’s profit and social welfare. This suggests the general principle that certification is, and should be induced by the better informed party. The results are reflected in a case study from the automotive industry, but apply also to other markets - in particular the financial market.asymmetric information, certification, information acquisition, inspection, lemons, middlemen, signaling

Firm dynamics in East Germany: first empirical results

In this paper, we report results of an ongoing empirical analysis of firm dynamics in East Germany. After discussing specifics of a newly available data set with information on more than 100.000 firms, we analyze patterns of business starts and failures. Furthermore, we present preliminary results on employment, revenue and labor productivity growth in East German firms. They suggest that large East German enterprises are characterized by significant labor shedding and small or no nominal revenue growth, resulting in an apparently impressive gain in labor productivity. Small firms turn out to be the carriers of employment growth. On average, they experience the highest revenue growth rates. However, the combination of revenue and employment growth yields labor productivity increases well below those of larger firms. --

Interstellar 12C/13C from CH+ absorption lines: Results from an extended survey

The 12C/13C isotope ratio in the interstellar medium (ISM), and its evolution with time, is an important tracer of stellar yields. Spatial variations of this ratio can be used to study mixing in the ISM. We want to determine this ratio and its spatial variations in the local ISM from CH+ absorption lines in the optical towards early-type stars. The aim is to determine the average value for the local ISM and study possible spatial variations. We observed a large number of early-type stars with Feros to extend the sample of suitable target stars for CH+ isotope studies. The best suited targets were observed with Uves with higher signal-to-noise ratio and spectral resolution to determine the isotope ratio from the interstellar CH+ lines. This study significantly expands the number of 13CH+ detections. We find an average ratio of = 76.27 +- 1.94 or, for f = 1/R, = (120.46 +- 3.02) 10^{-4}. The scatter in f is 6.3 sigma(). This findings strengthens the case for chemical inhomogeneity in the local ISM, with important implications for the mixing in the ISM. Given the large scatter, the present-day value in the ISM is not significantly larger than the solar value, which corresponds to the local value 4.5 Gyr ago.Comment: 11 pages, 16 figures, 2 tables, A&A submitte

Race, Class, And Gender In Boys\u27 Education: Repositioning Intersectionality Theory

Boys\u27 identities are distinctly gendered, racialized, and classed across disparate social and cultural contexts. Related intersectional identity processes are associated with boys\u27 academic success. While intersectionality has been utilized throughout boys\u27 education scholarship, a limited, light touch approach is often enacted. As a critical logic of interpretation, intersectionality theory accounts for race, class, and gender within equity-based empirical studies. The authors contend insufficient engagement with intersectionality may lead educational research on boys\u27 social and learner identities to become static. Examining boys\u27 identities through intersectional approaches reveals more complex insights particularly related to their school engagement. Critical of the recent boy crisis literature, this article strives to compel theorists of boys\u27 education to more fully leverage the history, constructs, and epistemologies of intersectionality

Market Transparency, Adverse Selection, and Moral Hazard

We study the effects of improvements in market transparency on eBay on seller exit and continuing sellers’ behavior. An improvement in market transparency by reducing strategic bias in buyer ratings led to a significant increase in buyer valuation especially of sellers rated poorly prior to the change, but not to an increase in seller exit. When sellers had the choice between exiting—a reduction in adverse selection—and improved behavior—a reduction in moral hazard—, they preferred the latter because of lower cost. Increasing market transparency improves on market outcomes

Labor Pooling in R&D Intensive Industries

We investigate firms’ incentives to locate in the same region to gain access to a large pool of skilled labor. Firms engage in risky R&D activities and thus create stochastic product and implied labor demand. Agglomeration in a cluster is more likely in situations where the innovation step is large and the probability for a firm to be the only innovator is high. When firms cluster, they tend to invest more and take more risk in R&D compared to spatially dispersed firms. Agglomeration is welfare maximizing, because expected labor productivity is higher and firms choose a more effcient, technically diversified portfolio of R&D projects at the industry level.

Competition and trust: Evidence from German car manufacturers

We explore the determinants and effects of trust relationships between upstream suppliers and downstream producers. Using unique survey data on individual supplier-buyer relationships in the German automotive industry, we show, by means of different measures of supplier-buyer trust, that higher levels of trust mitigate relationship-specific underinvestment in a classical hold-up situation. Moreover, contrary to the extant literature, we show that higher levels of supplier's trust are reflected in the buyer's choice of a more competitive procurement strategy among potential suppliers. --trust,hold-up problem,competition,specific investment,suppliers,car manufacturers,German automotive industry

Competition and Trust: Evidence from German Car Manufacturers

We explore the determinants and effects of trust relationships between upstream suppliers and downstream producers. Using unique survey data on individual supplier-buyer relationships in the German automotive industry, we show, by means of different measures of supplier-buyer trust, that higher levels of trust mitigate relationship-specific underinvestment in a classical hold-up situation. Moreover, contrary to the extant literature, we show that higher levels of supplier’s trust are reflected in the buyer’s choice of a more competitive procurement strategy among potential supplierstrust, hold-up problem, competition, specific investment, suppliers, car manufacturers, German automotive industry

Competition and Trust: Evidence from German Car Manufacturers

We explore the determinants and effects of trust relationships between upstream suppliers and downstream producers. Using unique survey data on individual supplier-buyer relationships in the German automotive industry, we show, by means of different measures of supplier-buyertrust, tha thigher levels of trust mitigate relationship-specific underinvestment in a classical hold-up situation. Moreover, contrary to the extant literature, we show that higher levels of supplier’s trust are reflected in the buyer’s choice of a more competitive procurement strategy among potential suppliers.Trust; Hold-up problem; Competition; Speci?c investment; Suppliers; Car manufacturers; German automotive industry