Protocol of a prospective study on the diagnostic value of transcranial duplex scanning of the substantia nigra in patients with parkinsonian symptoms

Background  

Parkinson's disease (PD) is the second most common neurodegenerative disorder. As there is no definitive diagnostic test, its diagnosis is based on clinical criteria. Recently transcranial duplex scanning (TCD) of the substantia nigra in the brainstem has been proposed as an instrument to diagnose PD. We and others have found that TCD scanning of substantia nigra duplex is a relatively accurate diagnostic instrument in patients with parkinsonian symptoms. However, all studies on TCD so far have involved well-defined, later-stage PD patients, which will obviously lead to an overestimate of the diagnostic accuracy of TCD.     

Increased contribution of wheat nocturnal transpiration to daily water use under drought

Increasing evidence suggests that in crops, nocturnal water use could represent 30% of daytime water consumption, particularly in semi‐arid and arid areas. This raises the questions of whether nocturnal transpiration rates (TR_N) are (1) less influenced by drought than daytime TR (TR_D), (2) increased by higher nocturnal vapor pressure deficit (VPD_N), which prevails in such environments and (3) involved in crop drought tolerance. In this investigation, we addressed those questions by subjecting two wheat genotypes differing in drought tolerance to progressive soil drying under two long‐term VPD_N regimes imposed under naturally fluctuating conditions. A first goal was to characterize the response curves of whole‐plant TR_N and TR_N/TR_D ratios to progressive soil drying. A second goal was to examine the effect of VPD_N increase on TR_N response to soil drying and on 13 other developmental traits. The study revealed that under drought, TR_N was not responsive to progressive soil drying and – intriguingly – that TR_N seemingly increased with drought under high VPD_N consistently for the drought‐sensitive genotype. Because TR_D was concomitantly decreasing with progressive drought, this resulted in TR_N representing up to 70% of TR_D at the end of the drydown. In addition, under drought, VPD_N increase was found not to influence traits such as leaf area or stomata density. Overall, those findings indicate that TR_N contribution to daily water use under drought might be much higher than previously thought, that it is controlled by specific mechanisms and that decreasing TR_N under drought might be a valuable trait for improving drought tolerance.     

Floristic variation and willow carr development within a southwest England wetland

Abstract. Woodland colonization on wetlands is considered to have a detrimental effect on their ecological value, even though detailed analysis of this process is lacking. This paper provides an evaluation of the ecological changes resulting from succession of poor fen (base‐poor mire) to willow wet woodland on Goss Moor NNR in Cornwall, UK. Different ages of willow carr were associated with eight understorey communities. During willow colonization, in the ground flora, there was a progressive decrease in poor fen species and an associated increase in woodland species, which appeared to be related to an increase in canopy cover and therefore shade. The most diverse community was found to be the most recent willow and was dominated by poor fen species. The oldest willow was the second most diverse and was associated with a reduction in poor fen species and an increase in woodland species. Architectural features were used successfully to assess the general condition and structure of willow. Tree height and DBH were identified as useful parameters to accurately assess willow age in the field. The implications of active intervention to remove willow in order to conserve the full range of communities within the hydrosere are discussed.     

Microfossils

Defining biosignatures, i.e. features that are indicative of past or present life, has been one of the major strategies developed over the last few years for the search of life on the early Earth and in the solar system. Current knowledge about microscopic remnants of fossil organisms, namely microfossils are reviewed, focusing on: (i) studies of recent environments used as analogues for the early Earth or extraterrestrial environments; (ii) examination of Precambrian rocks; and (iii) laboratory experiments simulating biotic and abiotic processes and resulting in the formation of genuine or pseudomicrofossils. Fossils’ preservation depends on environment and chemical composition of the primary structure, although they might undergo taphonomic processes that alter their morphology and/or composition. Altogether, these examples illustrate what can be potentially preserved during the very first stages of fossilization and what can be left in the geological record after diagenesis and metamorphism. Finally, this provides a rationale to tentatively define diagnosis criteria for microfossils or ways to look for life on Earth or in extraterrestrial environments.     

Correction to: Imaging plant responses to water deficit using electrical resistivity tomography

Plant and Soil - Soil microorganisms play an important role in biogeochemical cycles in terrestrial ecosystems. Increasing nitrogen (N) and phosphorus (P) deposition are likely to regulate...     

Lucky rugose corals on crinoid stems: unusual examples of subepidermal epizoans from the Devonian of Morocco

Berkowski, B & Klug, C. 2011: Lucky rugose corals on crinoid stems: unusual examples of subepidermal epizoans from the Devonian of Morocco. Lethaia, Vol. 45, pp. 24–33. In the fossil record, evidence for true epizoans, i.e. living animals inhabiting other living host‐animals, is rather rare. A host reaction is usually needed to proof the syn vivo‐settling of the epizoan. Herein, we provide a first report of such an epizoan biocoenosis from various strata of the Early Devonian of Hamar Laghdad, the world‐renowned Moroccan mud‐mound locality. In this case, solitary rugose corals settled as larvae on crinoid stems, perhaps at a spot where the epidermis was missing for some reason (injury, disease). Both the crinoid and the coral began to grow around each other. By doing so, the affected crinoid columnals formed a swelling, where ultimately only an opening slightly larger than the coral orifice remained. We discuss both macroecological and small‐scale synecological aspects of this biocoenosis. The coral profited from its elevated home because it reached into more rapid currents providing the polyp with more food than at the densely populated seafloor, which was probably covered by a coral‐meadow around the mounds and hydrothermal vents. □Corals, crinoids, Early Devonian, epizoans, Morocco, Rugosa.