35 research outputs found
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Modelling climate and societal resilience in the Eastern Mediterranean in the last Millennium
This article analyses high-quality hydroclimate proxy records and spatial reconstructions from the Central and Eastern Mediterranean and compares them with two Earth System Model simulations (CCSM4, MPI-ESM-P) for the Crusader period in the Levant (1095–1290 CE), the Mamluk regime in Transjordan (1260–1516 CE) and the Ottoman crisis and Celâlî Rebellion(1580–1610 CE). During the three time intervals, environmental and climatic stress tested the resilience of complex societies.We find that the multidecadal precipitation and drought variations in the Central and Eastern Mediterranean cannot be explained by external forcings (solar variations, tropical volcanism); rather they were driven by internal climate dynamics. Our research emphasises the challenges, opportunities and limitations of linking proxy records, palaeoreconstructions and model simulations to better understand how climate can affect human history
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Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the Clavicipitaceae reveals dynamics of alkaloid Loci
The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some—including the infamous ergot alkaloids—have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species), a morning-glory symbiont (Periglandula ipomoeae), and a bamboo pathogen (Aciculosporium take), and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories of the epichloae, their protective roles as symbionts, and their associations with the highly speciose and ecologically diverse cool-season grasses
Mobile Payload Element (MPE): concept study of a small, outonomous and innovative sample fetching rover
e.Deorbit Mission: OHB Debris Removal Concepts
To stabilize the space debris problem in low Earth orbit(LEO), the performance of active debris removalmissions is required. To prepare for such missions, theEuropean Space Agency (ESA) has initiated thee.Deorbit mission as part of its Clean Space activities,with ENVISAT as a sizing case for a potential removaltarget.For the phase A of e.Deorbit, OHB System has led ateam with strong heritage in the key fields of missiondesign, space robotics, and guidance, navigation andcontrol (GNC). In this paper, the mission concepts for removing spacedebris with a rigid or flexible capture mechanism arepresented. While re-orbiting was also studied, it is notaddressed in this paper.A key focus of the study has been the creation of a cost-effective design, allowing the high number of futureremoval missions needed for the stabilization ofthe space debris environment while not sacrificing thenecessary levels of reliability and safety
The chinese medtech sector with focus on new regulatory rules
Even though 95 per cent of the population is insured by basic medical insurance, the scheme does not address chronically ill patients who need long term treatment. China spends 5.8 per cent of its GDP on healthcare and the per capita expenditure is US 10 billion in 2015, as affluent people tend to avoid treatment in China. It seems obvious that in the future two different healthcare systems will coexist in China, namely: a large high-volume, low-priced public system and a small low-volume, high-priced private system. Since the large public system is controlled by the government, tender prices are bound to get lower
Mobile Payload Element: Concept Study for a Sample Fetching Rover for the ESA Lunar Lander Mission
Robotic Capture and De-Orbit of a Heavy, Uncooperative and Tumbling Target in Low Earth Orbit
This paper presents a robotic capture concept for large spacecraft in low Earth orbit (LEO) that was developed as part of the the e.Deorbit feasibility study within the scope of the clean space initiative of the European Space Agency (ESA). The defective and tumbling satellite ENVISAT has been chosen as potential target to be captured, stabilized, and subsequently de-orbited in a controlled manner. Following a thorough target analysis including potential grasping points, a robotic capture concept was developed that is based on a 7-DoF dexterous robotic manipulator, a linear two-bracket gripper, and a clamping mechanism for achieving stiff fixation between target and chaser satellites prior to the de-tumbling and execution of the de-orbit maneuver.
The robotic grasp concept includes a stereo-vision
camera system featuring a visual servoing algorithm for
camera-in-the-loop error correction. In addition, a
platform-mounted camera system is utilized for target
model building as well as relative motion and pose
estimation. For concept validation, visual servoing,
haptic grasp and capture simulations were performed.
The task-specific kinematics of the manipulator and
potential joint locks as contingency events were
validated and analyzed using the method of capability
maps. For the complete robotic capture maneuver, an
error budget was created and evaluated. Geometric
analysis and haptic grasp simulations showed that the
gripper design and connected grasp approach is feasible
and robust. In addition, the kinematics analysis yielded
a sufficient reachability, even in the case of an
improbable joint lock. FE-analyses were performed to
show that a high compound stiffness can be achieved by
the clamping device and that all required forces can be
transmitted without damaging the target’s structure.
Overall, the study showed that the capture and deorbiting
of ENVISAT is feasible and robust using the
developed robotic concept