Blue carbon stocks in Baltic Sea eelgrass (Zostera marina) meadows

Although seagrasses cover only a minor fraction of the ocean seafloor, their carbon sink capacity accounts for nearly one-fifth of the total oceanic carbon burial and thus play a critical structural and functional role in many coastal ecosystems. We sampled 10 eelgrass (<i>Zostera marina</i>) meadows in Finland and 10 in Denmark to explore seagrass carbon stocks (C_org stock) and carbon accumulation rates (C_org accumulation) in the Baltic Sea area. The study sites represent a gradient from sheltered to exposed locations in both regions to reflect expected minimum and maximum stocks and accumulation. The C_org stock integrated over the top 25 cm of the sediment averaged 627 g C m⁻² in Finland, while in Denmark the average C_org stock was over 6 times higher (4324 g C m⁻²). A conservative estimate of the total organic carbon pool in the regions ranged between 6.98 and 44.9 t C ha⁻¹. Our results suggest that the Finnish eelgrass meadows are minor carbon sinks compared to the Danish meadows, and that majority of the C_org produced in the Finnish meadows is exported. Our analysis further showed that &gt; 40 % of the variation in the C_org stocks was explained by sediment characteristics, i.e. dry density, porosity and silt content. In addition, our analysis show that the root : shoot ratio of <i>Z. marina</i> explained &gt; 12 % and the contribution of <i>Z. marina</i> detritus to the sediment surface C_org pool explained &gt; 10 % of the variation in the C_org stocks. The mean monetary value for the present carbon storage and carbon sink capacity of eelgrass meadows in Finland and Denmark, were 281 and 1809 EUR ha⁻¹, respectively. For a more comprehensive picture of seagrass carbon storage capacity, we conclude that future blue carbon studies should, in a more integrative way, investigate the interactions between sediment biogeochemistry, seascape structure, plant species architecture and the hydrodynamic regime

Dynamics of Bianchi type I elastic spacetimes

We study the global dynamical behavior of spatially homogeneous solutions of the Einstein equations in Bianchi type I symmetry, where we use non-tilted elastic matter as an anisotropic matter model that naturally generalizes perfect fluids. Based on our dynamical systems formulation of the equations we are able to prove that (i) toward the future all solutions isotropize; (ii) toward the initial singularity all solutions display oscillatory behavior; solutions do not converge to Kasner solutions but oscillate between different Kasner states. This behavior is associated with energy condition violation as the singularity is approached.Comment: 28 pages, 11 figure

Die Alltagssituation von Kindern in Stieffamilien und Kernfamilien im Vergleich

"Wie unterscheidet sich die Lebenssituation von Kindern in Stieffamilien im Vergleich mit Kindern in Kernfamilien? Wie erleben die Familien ihren Alltag? Wer wird als Familienmitglied betrachtet? Diesen Fragen geht eine systematische Untersuchung von acht Kern- und acht vergleichbaren Stieffamilien mit insgesamt 75 Personen nach; mindestens ein Kind war jeweils im Alter von acht Jahren oder älter; kein Familienmitglied befand sich in einer psychologischen Beratung. Es zeigten sich im Alltagsleben der beiden Familienformen überwiegend Gemeinsamkeiten. Unterschiede ergaben sich in der Familiendefinition und im Konfliktverhalten. Personen in Kernfamilien nannten Eltern und Kinder als Teile ihrer Familie, in Stieffamilien differierten die Familiendefinitionen sehr. Mitglieder in Stieffamilien stritten sich seltener. Als einflussreiche Faktoren für ein gelingendes Zusammenleben in Stieffamilien erwiesen sich vor allem die Zeit des Zusammenlebens als Familie und das Vorhandensein eines gemeinsamen Familiennamens und gemeinsamer Kinder." (Autorenreferat)"How does the situation of children living in step families differ from that of children in biological families? How do the families experience their daily lives? Who is regarded as a family member? Eight families of each type, a total of 75 family members, were interviewed. Each family had at least one child aged eight years or older and no family member was in psychological counseling. The daily lives of the two types of families show vast similiarities. Differences were found in the way the family was defined and in how they dealt with conflict. Whereas all members of biological families saw parents and children as family constituents, adults and children in step families had widely differing concepts of who belonged to their family. They reported less quarrelling than members of biological families. Factors contributing to the success of stepfamilies were: the length of time lived together, sharing a last name, and having common children." (author's abstract

Die Rolle des Vaters bei berufstätiger Mutter - Aufgabenbeteiligung, Lebenszufriedenheit und Schulleistung der Kinder

"Väterliche Rollenkonzepte, mütterliche Berufstätigkeit und die Zufriedenheit des Vaters in verschiedenen Lebensbereichen werden als Bedingungsfaktoren für die väterliche Beteiligung am Haushalt und an kindbezogenen Aufgaben untersucht und die Bedeutung dieser familiären Kontextvariablen für die Schulleistungen der Kinder in den Kernfächern Deutsch und Mathematik beleuchtet. Bei 279 Elternpaaren von Schülern und Schülerinnen in 3., 6. und 9. Klassen verschiedener Schultypen wurden Fragebogendaten erhoben. Väter mit berufstätigen Partnerinnen hatten ein egalitäreres Geschlechtsrollenkonzept und beteiligten sich insbesondere mehr an Haushaltsaufgaben, die als traditionell 'weiblich' angesehen werden. Beides hing mit besseren Schulleistungen der Söhne und Töchter im Fach Deutsch zusammen. Weitere Mediatoranalysen erbrachten, dass speziell in Familien mit berufstätigen Müttern das Ausmaß der Vater-Kind-Interaktion und die Zufriedenheit des Vaters mit der Beziehung zu seinen Kindern für die Schulnote in Mathematik relevant waren. Für die Aufgabenübernahme des Vaters war die von ihm empfundene Vereinbarkeit von Berufs- und Familienleben von großer Bedeutung." (Autorenreferat)"Fathers' role concept, life satisfaction in the work-family context and mothers' vocational participation are investigated as to their impact on fathers' involvement in child directed and household activities. Questionnaire data were collected of 279 couples with children in 3rd, 6th and 9th school grades. When mothers worked, fathers showed more egalitarian gender role concepts and participated more in household activities that are traditionally considered being 'feminine'. Mediator analyses revealed that such fathers' gender roles and participation had an impact on higher school achievement of sons and daughters in the German language subject. In families with working mothers, the amount of father-child-interaction and fathers' satisfaction with their father-child relationship correlated with children's proficiency in mathematics. Experiencing a satisfactory work-life balance strongly influenced fathers' family involvement." (author's abstract

Familienvorstellungen im Kulturkontakt: ein Vergleich italienischer, türkischer, koreanischer und deutscher junger Erwachsener in Deutschland

'In zwei Studien mit 215 Personen wurden die Vorstellungen zu Partnerschaft, Ehe und Familie von italienischen, türkischen und koreanischen jungen Erwachsenen der zweiten Migrantengeneration mit denen deutscher junger Erwachsener verglichen. In einer ersten Studie mit 115 Befragten der vier Ethnien, die repräsentativ nach dem Bildungsniveau zusammengesetzt waren, erwiesen sich die Voraussetzungen für eine Familiengründung und die antizipierte Rollenverteilung in der Familie als sehr unterschiedlich. So zeigten die italienischen und türkischen Erwachsenen eine starke Orientierung an familiären Traditionen und Werten, während die koreanischen und deutschen Teilnehmer die Individualität und die Rationalität des Einzelnen in den Vordergrund stellten. In einer zweiten Studie wurden weitere 100 Personen rekrutiert, um die Vorstellungen junger Erwachsener derselben ethnischen Gruppen mit Gymnasialbildung zu erhellen. Die Familienvorstellungen der jungen ausländischen Erwachsenen mit Abitur ähnelten denen der deutschen Untersuchungsteilnehmer. Vor allem italienische und türkische Frauen mit Gymnasialbildung zeigten signifikant andere Zukunftsvorstellungen als die entsprechenden Gruppen mit gemischten Bildungshintergründen.' (Autorenreferat)'Concepts of partnership, marriage and the family of a total of 215 young adults of different cultural backgrounds in Germany are compared. In an initial study, 115 German and Italian, Turkish and Korean young adults of the second migrant generation were interviewed; their achieved educational levels were representative for each group. The prerequisites for establishing a family and the anticipated role allocation within the family turned out to be very different. The Italian und Turkish adults showed a strong orientation towards family traditions and values, whereas the Korean and German participants emphasized individuality and rationality of the individual. In a second complementary study, 100 young adults of the same ethnic groups, who now all had an educational level of comprehensive secondary school, were recruited to investigate the family concepts in these specific groups. The young migrants had developed similar family concepts to those of their German peers. Especially Italian and Turkish women with comprehensive secondary school education revealed significantly different perceptions of the future in comparison to the concepts of the respective groups with mixed educational backgrounds.' (author's abstract

Quantum-Logic Gate between Two Optical Photons with an Average Efficiency above 40%

Optical qubits uniquely combine information transfer in optical fibers with a good processing capability and are therefore attractive tools for quantum technologies. A large challenge, however, is to overcome the low efficiency of two-qubit logic gates. The experimentally achieved efficiency in an optical controlled NOT (CNOT) gate reached approximately 11% in 2003 and has seen no increase since. Here we report on a new platform that was designed to surpass this long-standing record. The new scheme avoids inherently probabilistic protocols and, instead, combines aspects of two established quantum nonlinear systems: atom-cavity systems and Rydberg electromagnetically induced transparency. We demonstrate a CNOT gate between two optical photons with an average efficiency of 41.7(5)% at a postselected process fidelity of 81(2)%. Moreover, we extend the scheme to a CNOT gate with multiple target qubits and produce entangled states of presently up to five photons. All these achievements are promising and have the potential to advance optical quantum information processing in which almost all advanced protocols would profit from high-efficiency logic gates.Comment: In this revision, we extend the discussion of the efficiency in Sec. IV.C and we add models in appendices B, E, and L-

Perfect fluids and generic spacelike singularities

We present the conformally 1+3 Hubble-normalized field equations together with the general total source equations, and then specialize to a source that consists of perfect fluids with general barotropic equations of state. Motivating, formulating, and assuming certain conjectures, we derive results about how the properties of fluids (equations of state, momenta, angular momenta) and generic spacelike singularities affect each other.Comment: Considerable changes have been made in presentation and arguments, resulting in sharper conclusion

New explicit spike solution -- non-local component of the generalized Mixmaster attractor

By applying a standard solution-generating transformation to an arbitrary vacuum Bianchi type II solution, one generates a new solution with spikes commonly observed in numerical simulations. It is conjectured that the spike solution is part of the generalized Mixmaster attractor.Comment: Significantly revised. Colour figures simplified to accommodate non-colour printin