Journalists and aid workers – an ambivalent relationship

Commentary: The relationship between the news media and humanitarians remains extremely important as both play a key role in terms of shaping of what we know and how we experience armed conflicts of which most of us have no first-hand knowledge. By shaping public perceptions, these two actors also influence the actions taken by governments and the international community to put an end to or alleviate the suffering caused by wars. Yet, as this keynote address at the Reporting Wars conferences in Sydney and Wellington in May 2009 seeks to explain, there is nothing automatic about this process

Orbital frequencies in the carbonate sedimentary record: distorted by diagenesis?

The most important archive of Earth’s climate change through geologic history is the sedimentary rock record. Rhythmic sedimentary alternations are usually interpreted as a consequence of periodic variations in the orbital parameters of the Earth. This interpretation enables the application of cyclostratigraphy as a very precise chronometer, when based on the assumption that orbital frequencies are faithfully recorded in the sedimentary archive. However, there are numerous uncertainties with the application of this concept. Particularly in carbonates, sediment properties such as mineralogical composition and fossil associations are severely altered during post-depositional alteration (diagenesis). We here point out that the assumption of a 1:1 recording of orbital signals in many cases is questionable for carbonate rhythmites. We use computer simulations to show the effect of diagenetic overprint on records of orbital signals in the carbonate record. Such orbital signals may be distorted in terms of frequency, amplitude, and phase by diagenetic processes, and cycles not present in the insolation record may emerge. This questions the routine use of carbonate rhythmites for chronostratigraphic datin

Pelvic Girdle Reconstruction Based on Spinal Fusion and Ischial Screw Fixation in a Case of Aneurysmal Bone Cyst

A case of lytic lesion of the pelvis in a 23-year-old woman is presented. A biopsy led to the diagnosis aneurysmal bone cyst (ABC). Due to the histologically very aggressive growth of the tumor, a low malignant osteosarcoma could not be excluded. In an initial operation the tumour, affecting the sacrum, the iliac crest and the lower lumbar spine was resected. Temporary restabilisation of the pelvic ring was achieved by a titanium plate. The histological examination of the entire tumour confirmed the diagnosis ABC. After 6 months, the MRI showed no recurrence. The observed tilt of the spine to the operated side on the sacral base prompted a second surgical procedure: a transpedicular fixation of L5 and L4 was connected via bent titanium stems to the ischium, where the fixation was achieved by two screws. This construction allowed the correction of the base angle and yielded a stable closure of the pelvic ring. The patient has now been followed for 6 years: the bone grafts have been incorporated and, in spite of radiological signs of screw loosening in the ischium, the patient is fully rehabilitated and free of symptoms. Pedicle screws in the lower spine can be recommended for fixation of a pelvic ring discontinuity

Required but disguised: Environmental signals in limestone-marl alternations

The nature of rhythmic carbonate-rich successions such as limestone^marl alternations has been, and still is, subject to controversy. The possibility of an entirely diagenetic origin for the rhythmic calcareous alternations is discarded by most authors. One problem with an entirely diagenetic, self-organized development of limestone^marl alternations is the fact that limestone and marl beds in many examples are laterally continuous over hundreds of meters or even kilometers. In an entirely self-organized system, lateral coupling would be very limited; thus one would expect that, rather than laterally continuous beds, randomly distributed elongate nodules would form. We address the origin of limestone^marl alternations using a computer model that simulates differential diagenesis of rhythmic calcareous successions. The setup uses a cellular automaton model to test whether laterally extensive, rhythmic calcareous alternations could develop from homogeneous sediments in a process of self-organization. Our model is a strong simplification of early diagenesis in fine-grained, partly calcareous sediments. It includes the relevant key mechanisms to the question whether an external trigger is required in order to obtain laterally extensive limestone^ marl alternations. Our model shows that diagenetic self-organization alone is not sufficient to produce laterally extensive, correlatable beds. Although an external control on bedding formation could be considered to have solved the problem as commonly assumed, we here suggest an interesting third possibility: the rhythmic alternations were formed through the interaction of both an external trigger and diagenetic self-organization. In particular we observe that a very limited external trigger, either in time or amplitude, readily forms correlatable beds in our otherwise diagenetic model. Remarkably, the resulting rhythmites often do not mirror the external trigger in a one-to-one fashion and may differ in phase, frequency and number of couplets. Therefore, the interpretation of calcareous rhythmites as a one-to-one archive of climate fluctuations may be misleading. Parameters independent of diagenetic alteration should be considered for unequivocal interpretation

150 years Heterodera schachtii: A historical review of the early work

Mitte des 19. Jahrhunderts kam der Rübenanbau im damaligen Mitteldeutschland nahezu zum Erliegen. Die Suche nach den Ursachen der sogenannten Rübenmüdigkeit führte im Jahr 1859 zur Entdeckung des Rübenzystennematoden Heterodera schachtii durch den Botaniker Hermann Schacht. Obwohl sich Schacht recht intensiv mit der Morphologie und Biologie des Tieres befasste und ihm vermutlich bewusst war, dass es sich hierbei um eine neue Art handelte, vermied er es, dem Tier einen Namen zu geben. Dies holte Adolf Schmidt aus Aschersleben nach, indem er das Tier zu Ehren seines Entdeckers Heterodera schachtii nannte. Heterodera schachtii war der erste pflanzenparasitäre Nematode, der als Schaderreger unterirdischer Pflanzenorgane beschrieben wurde. Aufgrund seiner wirtschaftlichen Bedeutung für den Rübenanbau stand von Beginn an neben der Biologie vor allem die Entwicklung von Bekämpfungsmaßnahmen im Vordergrund des Forschungsinteresses. Hier ist es vor allem dem unermüdlichen Engagement und der intensiven Versuchstätigkeit von Prof. Julius Kühn aus Halle zu verdanken, dass innerhalb weniger Jahre Verfahren zur Vermeidung und Bekämpfung des Rübenzystennematoden erfolgreich in der Praxis etabliert wurden. Kühn zeigte, dass die Rübenmüdigkeit mit recht einfachen Mitteln verhindert werden konnte, dass solchen Methoden aber arbeits- und betriebswirtschaftliche Anforderungen entgegenstanden. Somit tragen intensive Rübenfruchtfolgen bis heute dazu bei, dass H. schachtii in gemäßigten Klimaregionen weltweit einer der wirtschaftlich bedeutendsten Schadnematoden ist. Anlässlich des 150jährigen Jubiläums der Entdeckung von H. schachtii sollen in diesem historischen Überblick die frühen Arbeiten zu diesem Nematoden vorgestellt werden, die in vielen Aspekten auch heute noch von hoher Aktualität sind.In the middle of the 1900 s, the production of sugarbeets severely declined in Central Germany. In 1859, the botanist Hermann Schacht discovered the sugar beet cyst nematode, Heterodera schachtii while searching for the cause of the observed “beet weariness”. Schacht intensively studied the morphology and biology of this animal; he probably was aware that he dealt with a new species but he avoided naming it. Adolf Schmidt (1871) of Aschersleben corrected this neglect and named the animal Heterodera schachtii in honor of its discoverer. Heterodera schachtii was the first plant-parasitic nematode described as feeding on below-ground plant parts. From the beginning and because of the nematode’s economic importance, the primary objectives of studies were focused on the development of management strategies in addition to investigations of its biology. Foremost due to the tireless efforts and intensive experimentation of Professor Julius Kühn of Halle, methods of avoidance and management strategies for the sugar beet cyst nematode were implemented in practical agriculture. Kühn demonstrated that fairly simple methods mitigated beet weariness but these were not always economically and logistically feasible. Therefore, H. schachtii remains among the most damaging plant-parasitic nematodes in moderate climates worldwide. In recognition of the 150-year anniversary of the discovery of H. schachtii, early works on this nematode are presented in this historical review to outline the implications of these for dealing with the sugar beet cyst nematode

Effects of heat shocks on biofilm formation and the influence on corrosion and scaling in a geothermal plant in the North German Basin

At geothermal plants, process failures often occur due to corrosion and scaling processes. Especially after heat extraction, sulfate reducing bacteria contribute to corrosion processes by producing reduced sulfur compounds. In biofilms containing scales such as iron sulfides, corrosion processes are enhanced. In a mobile bypass system located at the geothermal plant in Neubrandenburg (North German Basin), the influence of biofilm formation on corrosion and scaling was investigated. Short-term heat shocks were successfully tested in the bypass system in order to reduce biofilm formation and thus to diminish corrosion and scaling processes

Optically Induced Avoided Crossing in Graphene

Degenerate states in condensed matter are frequently the cause of unwanted fluctuations, which prevent the formation of ordered phases and reduce their functionalities. Removing these degeneracies has been a common theme in materials design, pursued for example by strain engineering at interfaces. Here, we explore a non-equilibrium approach to lift degeneracies in solids. We show that coherent driving of the crystal lattice in bi- and multilayer graphene, boosts the coupling between two doubly-degenerate modes of E1u and E2g symmetry, which are virtually uncoupled at equilibrium. New vibronic states result from anharmonic driving of the E1u mode to large amplitdues, boosting its coupling to the E2g mode. The vibrational structure of the driven state is probed with time-resolved Raman scattering, which reveals laser-field dependent mode splitting and enhanced lifetimes. We expect this phenomenon to be generally observable in many materials systems, affecting the non-equilibrium emergent phases in matter.Comment: 13 pages, 4 figure