Analysis of early bovine embryogenesis after in vitro and in vivo oocyte maturation by time-lapse imaging and 3-D confocal microscopy

In the in vitro production of embryos in humans and animals it is aimed to produce embryos of good quality in order to reach a high pregnancy rate after the transfer on a recipient. Nevertheless, data until 2007 show that in Europe the pregnancy rate after the transfer of human IVF embryos was only 33% (de Mouzon et al., 2012). Recently time-lapse imaging of early embryonic cleavage was found to be a helpful and non-invasive tool to predict the developmental capacity of embryos and select embryos of good quality (Wong et al., 2010, Sugimura et al., 2012). As the morphokinetic parameters of the first and second cleavage were the most predictive values, the fate of an embryo seems to be, at least partly, already determined very early in embryogenesis. This determination of the developmental competence might even go back further namely until oocyte maturation. In this experiment we used bovine embryos as an animal model to study the reasons for success and failure of mitotic cleavage during early embryo development. First a live monitoring system for the observation of bovine embryos was applied in order to search for the values that are highly predictable for the developmental competence to the blastocyst stage. To consider the effect of the oocyte maturation onto the further development, we observed embryos from oocytes after in vitro (n=398) versus in vivo maturation (n=143). In average embryos that developed to the blastocyst stage showed an earlier timing of the first, second and third cleavage than embryos that arrested (p<0.001). Nevertheless if the first cleavage occurred too early, the blastocyst rate also decreased. The reason for this observation is unclear and it was not described specifically for bovine embryos yet. Due to a high frequency of image acquisition, we could include the synchronicity of the second cleavage into our analyses. As already shown for human embryos we confirmed a decreasing blastocyst rate with increasing asynchronicity of the second cleavage in bovine embryos. Furthermore we observed three types of abnormal morphology during the first mitotic cleavage: 1) cleavage into two unequal sized blastomeres, 2) direct cleavage into VI. Summary 90 3- or for cells, 3) cleavage with fragments in the perivitelline space. Abnormal morphology of the first cleavage had a negative effect on the blastocyst rate as it was decreased about 25% compared to the blastocyst rate after normal first cleavage (p<0.001). In vitro versus in vivo maturation had no effect on the speed or morphology of the first and second cleavage. Nevertheless, from the third cleavage on until the development to the blastocyst stage we found embryos after in vivo maturation to be faster in development compared to the in vitro matured ones (p<0.01). Also the hatching rate was higher in blastocysts after in vivo maturation compared to in vitro maturation (p=0.001). Due to a logistic regression model the variables with the highest prediction rate were identified and based on two selected regression models the fate of an embryo regarding the blastocyst stage could be correctly classified in up to 76%. To get more insights into the normal and abnormal process of the first mitotic cleavage division we fixated embryos at defined time points and analyzed them with a confocal laser scanning microscope. 3-D images of embryos showed that fertilization with more than one sperm was a main cause for abnormal cleavage. Polyspermy could result in different cleavage patterns and could partly be associated with events observed under live observation. Accordingly too early timing of the first cleavage and abnormal morphology of the first cleavage are probably mainly caused by polyspermic fertilization. Accordingly time-lapse imaging was successfully applied to find values be able to predict the developmental competence of an embryo. In vivo maturation of oocytes had a positive effect on embryo development although this was only present from the third cleavage on. After 3-D confocal microscopic analysis, polyspermic fertilization seems to be a cause for abnormalities in timing and morphology of the first cleavage

Correlations in superstatistical systems

We review some of the properties of higher-dimensional superstatistical stochastic models. As an example, we analyse the stochastic properties of a superstatistical model of 3-dimensional Lagrangian turbulence, and compare with experimental data. Excellent agreement is obtained for various measured quantities, such as acceleration probability densities, Lagrangian scaling exponents, correlations between acceleration components, and time decay of correlations. We comment on how to proceed from superstatistics to a thermodynamic description.Comment: 8 pages, 4 figures. To appear in the proceedings of CTNEXT07 'Complexity, Metastability and Nonextensivity', Catania 1-5 July 2007, eds. S. Abe, H.J. Herrmann, P. Quarati, A. Rapisarda, C. Tsallis, AIP 200

A machine learning framework for LES closure terms

In the present work, we explore the capability of artificial neural networks (ANN) to predict the closure terms for large eddy simulations (LES) solely from coarse-scale data. To this end, we derive a consistent framework for LES closure models, with special emphasis laid upon the incorporation of implicit discretization-based filters and numerical approximation errors. We investigate implicit filter types, which are inspired by the solution representation of discontinuous Galerkin and finite volume schemes and mimic the behaviour of the discretization operator, and a global Fourier cutoff filter as a representative of a typical explicit LES filter. Within the perfect LES framework, we compute the exact closure terms for the different LES filter functions from direct numerical simulation results of decaying homogeneous isotropic turbulence. Multiple ANN with a multilayer perceptron (MLP) or a gated recurrent unit (GRU) architecture are trained to predict the computed closure terms solely from coarse-scale input data. For the given application, the GRU architecture clearly outperforms the MLP networks in terms of accuracy, whilst reaching up to 99.9% cross-correlation between the networks' predictions and the exact closure terms for all considered filter functions. The GRU networks are also shown to generalize well across different LES filters and resolutions. The present study can thus be seen as a starting point for the investigation of data-based modeling approaches for LES, which not only include the physical closure terms, but account for the discretization effects in implicitly filtered LES as well

Glücklose Medienfusionen

Weltweit verabschieden sich Medienunternehmen von ihrer Strategie eines integrierten Medienkonzerns und verkaufen ihre Beteiligungen. Die Argumente für eine Multimedia-Strategie klangen überzeugend, sie scheinen aber in der Realität nicht gegriffen zu haben. Was ist passiert? --

Variabilität von Makrozoobenthosproben und Bewertungsergebnissen der Fließgewässer vor dem Hintergrund der Umsetzung der EG-Wasserrahmenrichtlinie

Die vorliegende Arbeit thematisiert die Bewertung von Fließgewässern in Deutschland in Anlehnung an die EG-Wasserrahmenrichtlinie (EG-WRRL), wobei der Fokus auf der Qualitätskomponente Makrozoobenthos liegt. Im Teil A der Arbeit wurden verschiedene Ursachen der Variabilität von Makrozoobenthosproben sowie die Auswirkung der Variabilität auf Bewertungsergebnisse untersucht und quantifiziert. Das Ziel dieser Analysen war es, konkrete Vorschläge für die wasserwirtschaftliche Praxis machen zu können, um die Variabilität der Ergebnisse zu minimieren und somit möglichst stabile und reproduzierbare Bewertungsergebnisse für die Fließgewässer zu erhalten. Als Ergebnis dieser Analysen konnten u.a. folgende Aussagen getroffen werden: · Unterschiedliche Methoden zur Erfassung der Makrozoobenthosorganismen sind nur bedingt miteinander vergleichbar. Sie liefern deutlich unterschiedliche Taxa- und Individuenzahlen, was sich in abweichenden Bewertungsergebnissen widerspiegelt. · Eine methodisch einheitliche Erfassung an vergleichbaren Probestellen führt ebenfalls zu Unterschieden in Taxalisten und Bewertungsergebnissen. Es wird diskutiert, auf welche natürlichen oder methodisch bedingten Ursachen diese Unterschiede zurückzuführen sind. Als natürlich bedingte Ursache spielt die räumlich uneinheitliche Verteilung der Organismen im Fließgewässer eine Rolle („Patchiness“). Darüber hinaus kann auch bei Anwendung derselben Erfassungsmethode ein gewisser Anteil der Variabilität der Daten auf die einzelnen Bearbeitungsschritte zurückgeführt werden. · Die einzelnen taxonomischen Gruppen wurden hinsichtlich ihrer Bedeutung für die Bewertung der Fließgewässer untersucht. Insbesondere die Gruppen der Ephemeroptera, Trichoptera und Diptera konnten als solche Gruppen identifiziert werden, die für die Bewertung wichtig sind. Hinsichtlich der Bestimmung der Larven der Diptera lag jedoch für Mitteleuropa bislang kein zusammenfassendes und vollständiges Werk vor. Mit der Entwicklung eines an die Bedürfnisse der Praxis angepassten Bestimmungsschlüssels für die Larven der Diptera konnte diese Lücke geschlossen werden. Mit der Anpassung des Schlüssels an die Operationelle Taxaliste für Fließgewässer wird ein einheitliches Bestimmungsniveau vorgegeben, was zu einer Minimierung der Variabilität der Daten beiträgt. Aus diesen Ergebnissen resultierten die folgenden Vorschläge für die Bearbeitung der Qualitätskomponente Makrozoobenthos im Hinblick auf die Umsetzung der EG-WRRL in der wasserwirtschaftlichen Praxis: Für die Erfassung der Organismen sollte unbedingt eine einheitliche Methode zum Einsatz kommen. Anwender dieser Methode sollten geschult werden und insbesondere hinsichtlich der Sortierung und Bestimmung sollten qualitätssichernde Maßnahmen zum Einsatz kommen. Diese Ergebnisse wurden im Teil B der vorliegenden Arbeit genutzt, um für die Bäche der Jungmoräne des Alpenvorlandes (Gewässertyp 3.1) ein Bewertungssystem für das Modul „Allgemeine Degradation“ auf der Grundlage des Makrozoobenthos zu entwickeln. Obwohl die Bewertungsergebnisse insgesamt sehr gut mit der Einstufung der Gewässer übereinstimmten, wurde in Deutschland bislang noch nie das Augenmerk auf die Wahrscheinlichkeiten gelegt, mit denen Bewertungsergebnisse zutreffen. In der vorliegenden Arbeit wurde dieser Aspekt untersucht und festgestellt, dass die Bewertungsergebnisse der Gewässer ohne Aussagekraft waren. Dies hing mit der Wahrscheinlichkeit zusammen, mit der, unter Berücksichtigung der Varianz der Metricwerte, theoretisch alle fünf Zustandsklassen zutreffen konnten. Aussagen hinsichtlich eines Sanierungsbedarfs der Gewässer konnten auf der Grundlage dieser Ergebnisse nicht getroffen werden. In der vorliegenden Arbeit konnte die Lösung dieses Problems durch eine Transformierung der Metricwerte, die mit einer deutlichen Minimierung der Varianz der Metricwerte einherging, erreicht werden. Der Aufbau des Bewertungssystems auf der Grundlage transformierter Metricwerte ließ wesentlich eindeutigere Aussagen hinsichtlich des Sanierungsbedarfs der Gewässer zu. Eine Lösung, die auch bei der (Weiter-)Entwicklung von Bewertungssystemen anderer Fließgewässertypen bzw. Qualitätskomponenten in Zukunft berücksichtigt werden sollte

The remains of the taboo: experiences, attitudes, and knowledge about menopause in the workplace

Objectives: This study explored experiences of, attitudes to and knowledge about menopause in the workplace among participants from the UK to assess the extent to which the menopause remains a taboo in this context. Method: An online survey was distributed via TUC (Trades Union Congress, UK) networks and social media and was completed by 5399 respondents. Questions explored three key issues relating to menopause at work: respondents’ own experiences of menopause transition; disclosure at work; and availability of information on menopause at work. Result: The largest group (43.4%) of respondents were perimenopausal and 16.8% were post-menopausal. 12.3% indicated that they might be experiencing menopause but were not sure. Only 45.8% had disclosed their menopause status at work. Fewer than 20% were provided with information about menopause in their workplace but the majority would like such information to be available. Conclusion: The survey findings suggest some progress has been made to raise awareness about menopause in the workplace but that substantial work remains to be done to ensure women transitioning through menopause are supported

Is the Spatial Distribution of Mankind's Most Basic Economic Traits Determined by Climate and Soil Alone?

Background: Several authors, most prominently Jared Diamond (1997, Guns, Germs and Steel), have investigated biogeographic determinants of human history and civilization. The timing of the transition to an agricultural lifestyle, associated with steep population growth and consequent societal change, has been suggested to be affected by the availability of suitable organisms for domestication. These factors were shown to quantitatively explain some of the current global inequalities of economy and political power. Here, we advance this approach one step further by looking at climate and soil as sole determining factors.Methodology/Principal Findings: As a simplistic ‘null model’, we assume that only climate and soil conditions affect the suitability of four basic landuse types – agriculture, sedentary animal husbandry, nomadic pastoralism and hunting-andgathering. Using ecological niche modelling (ENM), we derive spatial predictions of the suitability for these four landuse traits and apply these to the Old World and Australia. We explore two aspects of the properties of these predictions, conflict potential and population density. In a calculation of overlap of landuse suitability, we map regions of potential conflict between landuse types. Results are congruent with a number of real, present or historical, regions of conflict between ethnic groups associated with different landuse traditions. Furthermore, we found that our model of agricultural suitability explains a considerable portion of population density variability. We mapped residuals from this correlation, finding geographically highly structured deviations that invite further investigation. We also found that ENM of agricultural suitability correlates with a metric of local wealth generation (Gross Domestic Product, Purchasing Power Parity).Conclusions/Significance: From simplified assumptions on the links between climate, soil and landuse we are able to provide good predictions on complex features of human geography. The spatial distribution of deviations from ENM predictions identifies those regions requiring further investigation of potential explanations. Our findings and methodological approaches may be of applied interest, e.g., in the context of climate change

Occurrence of tympanic bone spicules and bone crests in domestic cats

Small and hyperostotic tympanic bone spicules (STBS and HTBS) extending from the tympanic wall or from the septum bullae into the tympanic cavity have been described in large feline species such as Siberian tigers or African lions and in canids such as dogs, red foxes and wolves. Detailed descriptions of prevalence, location and orientation were performed for dogs and African lions by means of necropsy and conventional computed tomography (cCT). Aims of the current study were to describe same characteristics for domestic cats by means of microcomputed tomography (µCT) and cCT. A total of 15 cats or rather 30 ears were examined. Furthermore, new bone formations extending into the tympanic cavity shaped like small lamellae were found and named “tympanic bone crests” (TBCs). The registered phenomenon of a thickened tympanic wall in some cats was named “tympanic wall thickening” (TWT). STBS appeared in 43% of the ears being bilateral in 44% of the cases, whereas HTBS appeared in one ear. TBC was present in 33% of the ears with a bilateral prevalence of 67%, and TWT could be detected in 13% of the ears. The mentioned structures are just barely or not at all detectable with cCT; therefore, µCT is necessary for an identification and detailed description. The origin and the factors inducing the development of examined phenomena are unknown, and it is hypothesized that the occurrence can be assessed as anatomical norm variations