Synchronisation of the EDML and EDC ice cores for the last 52 kyr by volcanic signature matching

A common time scale for the EPICA ice cores from Dome C (EDC) and Dronning Maud Land (EDML) has been established. Since the EDML core was not drilled on a dome, the development of the EDML1 time scale for the EPICA ice core drilled in Dronning Maud Land was based on the creation of a detailed stratigraphic link between EDML and EDC, which was dated by a simpler 1D ice-flow model. The synchronisation between the two EPICA ice cores was done through the identification of several common volcanic signatures. This paper describes the rigorous method, using the signature of volcanic sulfate, which was employed for the last 52 kyr of the record. We estimated the discrepancies between the modelled EDC and EDML glaciological age scales during the studied period, by evaluating the ratio R of the apparent duration of temporal intervals between pairs of isochrones. On average R ranges between 0.8 and 1.2 corresponding to an uncertainty of up to 20% in the estimate of the time duration in at least one of the two ice cores. Significant deviations of R up to 1.4–1.5 are observed between 18 and 28 kyr before present (BP), where present is defined as 1950. At this stage our approach does not allow us unequivocally to find out which of the models is affected by errors, but assuming that the thinning function at both sites and accumulation history at Dome C (which was drilled on a dome) are correct, this anomaly can be ascribed to a complex spatial accumulation variability (which may be different in the past compared to the present day) upstream of the EDML core.

Nonverbale Synchronisation in Dyaden: ein Vergleich von kooperativen und kompetitiven Interaktionen

Nonverbales Verhalten spielt in zwischenmenschlichen Interaktionen eine bedeutende Rolle. Es beeinflusst mutmaßlich den Verlauf eines Gesprächs, die Beziehung zwischen den Interaktionspartnern und die reziproke Sympathie. Trotz dieser immensen Bedeutung wird nonverbales Verhalten von den Beteiligten meist nicht bewusst wahrgenommen. Die vorliegende Arbeit widmet sich diesem wirkungsvollen Phänomen und vergleicht nonverbales Verhalten in kooperativen und kompetitiven Interaktionsbedingungen. Im Fokus der Experimentalstudie steht die nonverbale Synchronisation. Diese bezieht sich auf den dynamischen, quantitativen Aspekt der Koordination nonverbalen Verhaltens zwischen den Interaktionspartnern, konkret auf die Angleichung der Bewegungsenergie. Primäres Ziel ist es zu evaluieren, ob und inwiefern das nonverbale Verhalten, insbesondere das Ausmaß an Synchronisation, zwischen kooperativen und kompetitiven Bedingungen variiert. Hierzu wurden in einer Stichprobe von N = 168 gesunden Teilnehmern fünf standardisierte Interaktionen à fünf Minuten mit gleichgeschlechtlichen Dyaden realisiert. Die Probanden kannten sich vorher nicht. Die Interaktanten sahen sich aufgefordert, sowohl aktive Kooperationen zu etablieren, als auch in bestimmten Aufgaben zu konkurrieren. Kompromiss, Konsens, Konflikt, ungleicher Konflikt und Spiel waren die verschiedenen Bedingungen. Die resultierenden Synchronisationswerte basieren auf digitalen Videoaufnahmen von dyadischen Interaktionen, die durch das automatisierte, objektive Verfahren der Motion Energy Analysis (MEA) quantifiziert wurden. Neben den Synchronisationsprozessen wurden auch globale Bewegungscharakteristika wie Geschwindigkeit oder Maxima durch MEA erfasst. Des Weiteren wurden mittels Fragebögen individuelle Charakteristika (u.a. Empathie, Stimmung) sowie Einschätzungen (z.B. Sympathie) der Probanden erhoben und mit Synchronie in Zusammenhang gesetzt. Die Ergebnisse zeigen, dass sich nonverbale Synchronisation auf signifikant höherem Level manifestiert, als dies per Zufall erwartet werden könnte. Dabei war die Synchronisation in der spielerischen Kooperation am höchsten ausgeprägt - gefolgt von kompetitiven und (seriös-)kooperativen Interaktionen. Außerdem korrespondierten höhere Synchronisationswerte mit verstärkt positiven Affekten und verringerten negativen Emotionen. Darüber hinaus waren globale Bewegungsparameter wie Dauer und Komplexität oder der Prozentsatz von Bewegungen über dem Schwellenwert positiv mit Synchronisationsprozessen assoziiert. Das MEA-Verfahren sowie ein erstmals erprobtes Interaktionsparadigma konnten validiert werden.

Spawning coordination of mates in a shell brooding cichlid

Aim. External fertilisation requires synchronisation of gamete release between the two sexes. Adequate synchronisation is essential in aquatic media because sperm is very short-lived in water. In the cichlid Lamprologus callipterus, fertilisation of the eggs takes place inside an empty snail shell, where females stay inside the shell and males have to ejaculate into the shell opening. This spawning pattern makes the coordination of gamete release difficult. Methods. This study examined the synchronisation of males and females during egg laying. Results. The results showed that the male initiates each spawning sequence and that sperm release and egg laying are very well synchronised. 68% of all sperm releases occurred at exactly the same time when the female laid an egg, and 99% of ejaculations occurred within ±5 seconds from egg deposition. On average 95 eggs are laid one by one with intervals of several minutes between subsequent eggs, leading to a total spawning duration in excess of six hours. Conclusions. We discuss this exceptional spawning pattern and how it might reflect a conflict between the sexes, with males attempting to induce egg laying and females extending the egg laying period to raise the chance for parasitic males to participate in spawning.

Direct north-south synchroniszation of abrupt climate change record in ice cores using Beryllium 10

A new, decadally resolved record of the 10Be peak at 41 kyr from the EPICA Dome C ice core (Antarctica) is used to match it with the same peak in the GRIP ice core (Greenland). This permits a direct synchronisation of the climatic variations around this time period, independent of uncertainties related to the ice age-gas age difference in ice cores. Dansgaard-Oeschger event 10 is in the period of best synchronisation and is found to be coeval with an Antarctic temperature maximum. Simulations using a thermal bipolar seesaw model agree reasonably well with the observed relative climate chronology in these two cores. They also reproduce three Antarctic warming events observed between A1 and A2.

TDOA-Based Localization System with Narrow-band Signals

This paper gives a general overview of the challenges that arise in using narrow-band signals, such as GSM, for localisation based on the time properties of the signal. Specifically, synchronisation and retrieving of time information are addressed. We pursue two contributions, namely, analysis of achievable synchronisation precision and processing of narrowband signals that can enable localization down to a meter. Keywords-localization, narrow band signals, TOA, TDOA I.

Cell cycle-dependent phosphorylation of Theileria annulata schizont surface proteins.

The invasion of Theileria sporozoites into bovine leukocytes is rapidly followed by the destruction of the surrounding host cell membrane, allowing the parasite to establish its niche within the host cell cytoplasm. Theileria infection induces host cell transformation, characterised by increased host cell proliferation and invasiveness, and the activation of anti-apoptotic genes. This process is strictly dependent on the presence of a viable parasite. Several host cell kinases, including PI3-K, JNK, CK2 and Src-family kinases, are constitutively activated in Theileria-infected cells and contribute to the transformed phenotype. Although a number of host cell molecules, including IkB kinase and polo-like kinase 1 (Plk1), are recruited to the schizont surface, very little is known about the schizont molecules involved in host-parasite interactions. In this study we used immunofluorescence to detect phosphorylated threonine (p-Thr), serine (p-Ser) and threonine-proline (p-Thr-Pro) epitopes on the schizont during host cell cycle progression, revealing extensive schizont phosphorylation during host cell interphase. Furthermore, we established a quick protocol to isolate schizonts from infected macrophages following synchronisation in S-phase or mitosis, and used mass spectrometry to detect phosphorylated schizont proteins. In total, 65 phosphorylated Theileria proteins were detected, 15 of which are potentially secreted or expressed on the surface of the schizont and thus may be targets for host cell kinases. In particular, we describe the cell cycle-dependent phosphorylation of two T. annulata surface proteins, TaSP and p104, both of which are highly phosphorylated during host cell S-phase. TaSP and p104 are involved in mediating interactions between the parasite and the host cell cytoskeleton, which is crucial for the persistence of the parasite within the dividing host cell and the maintenance of the transformed state.

A tephra lattice for Greenland and a reconstruction of volcanic events spanning 25–45 ka b2k

Tephra layers preserved within the Greenland ice-cores are crucial for the independent synchronisation of these high-resolution records to other palaeoclimatic archives. Here we present a new and detailed tephrochronological framework for the time period 25,000 e 45,000 a b2k that brings together results from 4 deep Greenland ice-cores. In total, 99 tephra deposits, the majority of which are preserved as cryptotephra, are described from the NGRIP, NEEM, GRIP and DYE-3 records. The major element signatures of single glass shards within these deposits indicate that 93 are basaltic in composition all originating from Iceland. Specifically, 43 originate from Grimsv € otn, 20 are thought to be sourced from the Katla volcanic system and 17 show affinity to the Kverkfj € oll system. Robust geochemical characterisations, independent ages derived from the GICC05 ice-core chronology, and the stratigraphic positions of these deposits relative to the Dansgaard-Oeschger climate events represent a key framework that provides new information on the frequency and nature of volcanic events in the North Atlantic region between GS-3 and GI-12. Of particular importance are 19 tephra deposits that lie on the rapid climatic transitions that punctuate the last glacial period. This framework of well-constrained, time-synchronous tie-lines represents an important step towards the independent synchronisation of marine, terrestrial and ice-core records from the North Atlantic region, in order to assess the phasing of rapid climatic changes during the last glacial period.