Period, epoch and prediction errors of ephemeris from continuous sets of timing measurements

Space missions such as Kepler and CoRoT have led to large numbers of eclipse or transit measurements in nearly continuous time series. This paper shows how to obtain the period error in such measurements from a basic linear least-squares fit, and how to correctly derive the timing error in the prediction of future transit or eclipse events. Assuming strict periodicity, a formula for the period error of such time series is derived: sigma_P = sigma_T (12/( N^3-N))^0.5, where sigma_P is the period error; sigma_T the timing error of a single measurement and N the number of measurements. Relative to the iterative method for period error estimation by Mighell & Plavchan (2013), this much simpler formula leads to smaller period errors, whose correctness has been verified through simulations. For the prediction of times of future periodic events, the usual linear ephemeris where epoch errors are quoted for the first time measurement, are prone to overestimation of the error of that prediction. This may be avoided by a correction for the duration of the time series. An alternative is the derivation of ephemerides whose reference epoch and epoch error are given for the centre of the time series. For long continuous or near-continuous time series whose acquisition is completed, such central epochs should be the preferred way for the quotation of linear ephemerides. While this work was motivated from the analysis of eclipse timing measures in space-based light curves, it should be applicable to any other problem with an uninterrupted sequence of discrete timings for which the determination of a zero point, of a constant period and of the associated errors is needed.Comment: Astronomy and Astrophysics, accepte

German banks and industrial finance in the 1990s

This paper examines the role of the banking system in the German model ofindustrial development. It argues that the banks continue to fulfill several of theirtraditional functions in industrial finance, despite dramatic changes in financial regulation and the internationalisation of product and capital markets. This helps explain the successful adjustment of German industry since the early 1970s. The success of the traditional financial system, however, is at the same time a barrier to the creation of new high-tech industries - a major competitive challenge for Germany. Moreover, an emerging dualism in the banking system is evident as large Germanfirms increasingly seek an Anglo-Saxon style financial market with emphasis onsecurities financing, while small and medium size enterprises continue to rely on the traditional system of long-term bank financing. In this sense Germany is attemptingto combine its traditional bank-based finance system with Anglo-Saxon market-based finance, hoping to achieve the advantages of each system and eliminate the disadvantages. Success in this endeavor has been modest. -- In diesem Papier wird die Rolle des Bankensystems in Deutschland in demdeutschen Modell einer industriellen Entwicklung untersucht. Dabei wird die Meinung vertreten, daß die Banken trotz dramatischer Änderungen in der Regulierung des Finanzsystems und der Internationalisierung der Finanz- und Gütermärkte immernoch einige ihrer traditionellen Funktionen in der Unternehmensfinanzierung erfüllen.Dies erklärt teilweise die seit den frühen siebziger Jahren erfolgreiche Anpassung der Industrie in Deutschland. Der Erfolg des traditionellen Finanzsystems ist aber auch gleichzeitig ein Hindernis bei der Entwicklung und Herausbildung neuer High-Tech-Industrien. Dies bedeutetfür Deutschland eine gewichtige Herausforderung seiner Wettbewerbsfähigkeit.Darüberhinaus ist ein sich aufbauender Dualismus im Bankensystem immer deutlicher festzustellen: Große Unternehmen wenden sich immer mehr angelsächsisch geprägten Finanzmärkten mit ihrer besonderen Orientierung aufFinanzierungen qua Aktien und Schuldverschreibungen zu, während kleine und mittlere Unternehmen sich weiterhin auf das traditionelle System langfristiger Bankenfinanzierung stützen. In dieser Hinsicht wird in Deutschland versucht, das traditionelle, sich auf Banken stützende Finanzsystem mit dem angelsächsischen marktgestützten Finanzsystem zu kombinieren in der Hoffnung, die Vorteile beider Systeme nutzen und ihre Nachteile vermeiden zu können. Der Erfolg in diesen Bemühungen war allerdings bisher bescheiden.

Institutional change and the uses and limits of path dependency: The case of German finance

How can we determine when an existing institutional path or trajectory is ending and being replaced with a new one? How does such a process take place? How can we distinguish between institutional innovation within an existing trajectory and a switchover to a new trajectory or path? This paper explores these questions by examining the pattern of institutional change in the German financial system. The paper advances four theoretical claims: First, that endogenous developments can disrupt an institutional path and lead to a new one. Second, that an event sequence involving a move to a new institutional path may not follow from a contingent event yet may nonetheless be marked by increasing returns processes. Third, that increasing returns in politics are not automatic and must be cultivated by actors in order to be realized. Finally, that the concept of path is still in need of a measurable conceptualization before any further advances in path dependent arguments can be made. -- Wie lässt sich bestimmen, wann ein bestehender institutioneller Pfad endet und durch einen neuen ersetzt wird? Wie vollzieht sich ein solcher Prozess? Wie kann zwischen einer institutionellen Innovation im Rahmen einer bestehenden Trajektorie und dem Wechsel zu einem neuen Pfad unterschieden werden? Zur Beantwortung dieser Fragen werden die Muster des institutionellen Wandels im deutschen Finanzsystem untersucht. Dabei werden vier Thesen aufgestellt. Erstens: Endogene Entwicklungen können dazu führen, dass ein institutioneller Pfad unterbrochen und durch einen neuen abgelöst wird. Zweitens: Eine Ereignisfolge, die eine Hinwendung zu einem neuen institutionellen Pfad nach sich zieht, muß nicht unbedingt durch ein kontingentes Ereignis ausgelöst werden, kann aber gleichwohl auf positiven Rückkopplungen und wachsenden Skalenerträgen beruhen. Drittens: Solche Skaleneffekte entstehen in der Politik nicht automatisch, sondern müssen von den Akteuren aktiv gefördert und kultiviert werden. Schließlich: Das Konzept der Pfadabhängigkeit bedarf nach wie vor einer messbaren Konzeptualisierung, bevor weiterführende Thesen im Rahmen dieses Ansatzes formuliert werden können.

Starburst ages in HII galaxies

The age of the starbursts of a few H2 galaxies is derived from optical photometry and compared with previous results from radio continuum spectra. H2 galaxies are gas rich and characterized by the dominance of giant H2 regions, blue stellar colors, high surface brightness, and narrow emission lines. The presently observed high abundances of bright young stars must be the result of a recent -or even ongoing- starburst. The question, whether the observed starburst is the first one or if it is a recurrent phenomenon, is still open. If the starburst is the first one, H2 galaxies can be interpreted as being among the most unevolved galaxies known - their star formation characteristics possibly paralleling that of normal galaxies early in their evolution. A sample of five H2 galaxies was observed with B, R, and I broadband filters. They have been observed previously at several radio continuum frequencies. The photometric data are given. The results of the photometry and a comparison with radio continuum spectra are given

TEE, a simple estimator for the precision of eclipse and transit minimum times

Context: Transit or eclipse timing variations have proven to be a valuable tool in exoplanet research. However, no simple way to estimate the potential precision of such timing measures has been presented yet, nor are guidelines available regarding the relation between timing errors and sampling rate. Aims: A `timing error estimator' (TEE) equation is presented that requires only basic transit parameters as input. With the TEE, it is straightforward to estimate timing precisions both for actual data as well as for future instruments, such as the TESS and PLATO space missions. Methods: A derivation of the timing error based on a trapezoidal transit shape is given. We also verify the TEE on realistically modeled transits using Monte Carlo simulations and determine its validity range, exploring in particular the interplay between ingress/egress times and sampling rates. Results: The simulations show that the TEE gives timing errors very close to the correct value, as long as the temporal sampling is faster than transit ingress/egress durations and transits with very low S/N are avoided. Conclusions: The TEE is a useful tool to estimate eclipse or transit timing errors in actual and future data-sets. In combination with an equation to estimate period errors (Deeg 2015), predictions for the ephemeris precision of long-coverage observations are possible as well. The tests for the TEE's validity-range led also to implications for instrumental design: Temporal sampling has to be faster than transit in- or egress durations, or a loss in timing-precision will occur. An application to the TESS mission shows that transits close to its detection limit will have timing uncertainties that exceed 1 hour within a few months after their acquisition. Prompt follow-up observations will be needed to avoid a `loosing' of their ephemeris.Comment: Accepted by A&A. Version 2 with updated timing uncertainties of TESS mission due to correction of a figure in Sullivan et al. 201

Profound Re-Organization of Cell Surface Proteome in Equine Retinal Pigment Epithelial Cells in Response to In Vitro Culturing

The purpose of this study was to characterize the cell surface proteome of native compared to cultured equine retinal pigment epithelium (RPE) cells. The RPE plays an essential role in visual function and represents the outer blood-retinal barrier. We are investigating immunopathomechanisms of equine recurrent uveitis, an autoimmune inflammatory disease in horses leading to breakdown of the outer blood-retinal barrier and influx of autoreactive T-cells into affected horses' vitrei. Cell surface proteins of native and cultured RPE cells from eye-healthy horses were captured by biotinylation, analyzed by high resolution mass spectrometry coupled to liquid chromatography (LC MS/MS), and the most interesting candidates were validated by PCR, immunoblotting and immunocytochemistry. A total of 112 proteins were identified, of which 84% were cell surface membrane proteins. Twenty-three of these proteins were concurrently expressed by both cell states, 28 proteins exclusively by native RPE cells. Among the latter were two RPE markers with highly specialized RPE functions: cellular retinaldehyde-binding protein (CRALBP) and retinal pigment epithelium-specific protein 65kDa (RPE65). Furthermore, 61 proteins were only expressed by cultured RPE cells and absent in native cells. As we believe that initiating events, leading to the breakdown of the outer blood-retinal barrier, take place at the cell surface of RPE cells as a particularly exposed barrier structure, this differential characterization of cell surface proteomes of native and cultured equine RPE cells is a prerequisite for future studies

Identifying Transiting Circumbinary Planets

Transiting planets manifest themselves by a periodic dimming of their host star by a fixed amount. On the other hand, light curves of transiting circumbinary (CB) planets are expected to be neither periodic nor to have a single depth while in transit, making BLS [Kovacs et al. 2002] almost ineffective. Therefore, a modified version for the identification of CB planets was developed - CB-BLS. We show that using CB-BLS it is possible to find CB planets in the residuals of light curves of eclipsing binaries (EBs) that have noise levels of 1% or more. Using CB-BLS will allow to easily harness the massive ground- and space- based photometric surveys to look for these objects. Detecting transiting CB planets is expected to have a wide range of implications, for e.g.: The frequency of CB planets depend on the planetary formation mechanism - and planets in close pairs of stars provides a most restrictive constraint on planet formation models. Furthermore, understanding very high precision light curves is limited by stellar parameters - and since for EBs the stellar parameters are much better determined, the resultant planetary structure models will have significantly smaller error bars, maybe even small enough to challenge theory.Comment: To appear on the IAU Symposium 253 proceedings. 4 pages, 4 figure

Probing the Stellar Surface of HD 209458 from Multicolor Transit Observations

Multicolor photometric observations of a planetary transit in the system HD 209458 are analyzed. The observations, made in the Stromgren photometric system, allowed a recalculation of the basic physical properties of the star-planet system. This includes derivation of linear limb-darkening values of HD 209458, which is the first time that a limb-darkening sequence has observationally been determined for a star other than the Sun. As the derived physical properties depend on assumptions that are currently known with limited precision only, scaling relations between derived parameters and assumptions are given. The observed limb-darkening is in good agreement with theoretical predictions from evolutionary stellar models combined with ATLAS model atmospheres, verifying these models for the temperature (Teff ~ 6000K), surface gravity (log g ~ 4.3) and mass (~ 1.2 Msol) of HD 209458.Comment: 16 pages, 8 figures, uses elsart.cls, accepted for New Astronom

Using Stellar Densities to Evaluate Transiting Exoplanetary Candidates

One of the persistent complications in searches for transiting exoplanets is the low percentage of the detected candidates that ultimately prove to be planets, which significantly increases the load on the telescopes used for the follow-up observations to confirm or reject candidates. Several attempts have been made at creating techniques that can pare down candidate lists without the need of additional observations. Some of these techniques involve a detailed analysis of light curve characteristics; others estimate the stellar density or some proxy thereof. In this paper, we extend upon this second approach, exploring the use of independently-calculated stellar densities to identify the most promising transiting exoplanet candidates. We use a set of CoRoT candidates and the set of known transiting exoplanets to examine the potential of this approach. In particular, we note the possibilities inherent in the high-precision photometry from space missions, which can detect stellar asteroseismic pulsations from which accurate stellar densities can be extracted without additional observations.Comment: 33 pages, 9 figure