Les Pissenlits des marais (Taraxacum sect. Palustria) en Hesse

7 Sumpflöwenzahn-Arten sind in Hessen nachgewiesen, wobei von Taraxacum bavaricum und T. pauckertianum nur historische Nachweise vorliegen. Taraxacum hollandicum ist am weitesten in Hessen verbreitet und konnte bei der zwischen 2002 und 2004 durchgeführten Untersuchung in 10 von 12 untersuchten Gebieten mit mehr als 35000 Exemplaren nachgewiesen werden. Taraxacum germanicum wurde bei Münzenberg, Selters und im Mönchbruch gefunden. Taraxacum multilepis und T. trilobifolium haben individuenarme Populationen im Naturschutzgebiet Ludwigsquelle beziehungsweise im Mönchbruch, auf der Rodwiese und bei Bieber. Taraxacum subalpinum ist mit 2 sehr kleinen Populationen in der Wieseckaue bei Gießen die seltenste hessische Sumpflöwenzahnart.Seven species of Taraxacum sect. Palustria are known to have occurred in Hesse, of which T. bavaricum and T. pauckertianum now appear to be extinct. T. hollandicum is the most widespread species, with more than 35,000 plants recorded in a survey conducted between 2002 and 2004 in 10 areas in the Wetterau district and in southern Hesse. T. germanicum was found near Muenzenberg, Selters, and Moenchbruch. A sparse population of T. multilepis was found in the Ludwigsquelle conservation area, and a sparse population of T. trilobifolium was found near Moenchbruch, Rodwiese, and Bieber. T. subalpinum is rare, with only two very small populations occurring in the Wieseck valley near Giessen.7 espèces de pissenlits des marais sont prouvées en Hesse dont 2 espèces (Taraxacum bavaricum, T. pauckertianum) ne sont connues que par l’histoire. Taraxacum hollandicum est le plus répandu en Hesse. Grâce aux recherches qui ont été effectuées entre 2002 et 2004, il a pu être prouvé plus de 35 000 exemplaires sur 10 des 12 aires examinées. Taraxacum germanicum a été trouvé près de Münzenberg, de Selters et dans le Mönchbruch. Taraxacum multilepis et T. trilobifolium ont de rares populations de quelques spécimens dans la réserve naturelle du Ludwigsquelle et dans le Mönchbruch, sur la Rodwiese et près de Bieber. Taraxacum subalpinum, la plus rare des espèces en Hesse, a deux très petites populations dans la zone de Wieseckaue près de Gießen

Early Cretaceous sea surface temperature evolution in subtropical shallow seas

Late Cretaceous sea surface temperatures (SST) are, amongst others, traditionally reconstructed by compiling oxygen isotope records of planktonic foraminifera obtained from globally distributed pelagic IODP drill cores. In contrast, the evolution of Early Cretaceous SSTs is essentially based on the organic TEX86 palaeothermometer, as oxygen-isotope data derived from well-preserved ‘glassy’ foraminifer calcite are currently lacking. In order to evaluate the extraordinary warm TEX86-derived SSTs of the Barremian to Aptian (130–123 Ma) subtropics, we present highly resolved sclerochemical profiles of pristine rudist bivalve shells from Tethyan and proto-North Atlantic shallow water carbonate platforms. An inverse correlation of seasonal ontogenetic variations in δ18Orudist and Mg/Ca ratios demonstrates the fidelity of oxygen isotopes as palaeotemperature proxy. The new data shows moderate mean annual SSTs (22–26 °C) for large parts of the Barremian and Aptian and transient warm pulses for the so-called Mid-Barremian Event and Oceanic Anoxic Event 1a (reaching mean annual SSTs of 28 to 30 °C). A positive shift in mean annual oxygen-isotope values (δ18O: ≤ − 0.3‰) coupled with invariant Mg/Ca ratios at the Barremian–Aptian boundary points to a significant net loss of 16O in Tethyan shallow-marine settings. As the positive oxygen-isotope rudist shell values are recorded immediately beneath a major superregional hiatal surface, they are interpreted to be related to a major cooling phase and potential glacio-eustatic sea-level lowering. Our new sclerochemical findings are in clear contrast to open ocean SST records based on TEX86, which indicate exceptionally warm Barremian to earliest Aptian subtropical oceans and weak meridional SST gradients

Decisions-making in Agile Information Systems Development: The Role of Empowerment and Authority

Agile information systems development (ISD) teams are claimed to work via self-organized and autonomous methods. Yet little research exists on how these teams make decisions. Therefore, this research-in-progress paper conceptualizes a multilevel model that examines decision-making–team empowerment and project managers’ decision-making authority–in agile ISD teams and its effect on team members’ work engagement and performance. Preliminary results show satisfactory psychometric criteria for the measurement instrument. Within the main study, multilevel analyses using hierarchical linear modeling and hierarchical linear regression will be used to examine cross-level effects. We expect our research to contribute to deeper understanding of agile ISD teams’ decision-making and to the limited evidence on project managers’ role in agile ISD

L’Euphraise nordique (Euphrasia frigida) en Hesse

Der Nordische Augentrost (Euphrasia frigida) ist eine boreal-montane Art, die einige vom Hauptareal abgesetzte Vorposten in deutschen Mittelgebirgen besitzt, wo sie extensiv genutztes, in der Regel ungedüngtes Grünland besiedelt. Aus den hessischen Mittelgebirgen lagen neuere Nachweise nur aus dem nördlichen Spessart vor (vier Populationen). Im Rahmen des Artenhilfsprogramms (und außerdem bei zwei FFH-Grunddatenerfassungen) konnten sechs weitere Spessart-Vorkommen festgestellt werden. Hinweise auf ein kleines Vorkommen im Hochtaunus (Neufund für den Naturraum) konnten bestätigt werden. Die Nachsuche an ehemaligen Wuchsorten im Vogelsberg, wo die Art bis in die 1970er Jahre vorkam, verlief hingegen durchweg erfolglos; allerdings gelang auch hier der Neufund einer kleinen Population. Auch im hessischen Teil der Hohen Rhön gelang inzwischen ein Erstnachweis (siehe Barth 2008). Insgesamt liegt mehr als die Hälfte aller bekannten deutschen Fundorte in Hessen. Dem Land kommt daher eine besondere Verantwortung für die Erhaltung der Art zu. Hauptgefährdungsursachen für die Art sind Nutzungsintensivierung (Düngung, zu früher Mahdtermin) und Nutzungsaufgabe sowie die Aufforstung von Grenzertragsgrünland. Die Erhaltung der Art ist am besten durch vertraglich vereinbarte extensive Grünlandnutzung (Verzicht auf Düngung, Mahd nicht vor Anfang Juli) zu gewährleisten.The Cold Eyebright (Euphrasia frigida) has a boreo-montane distribution in Europe, Asia, and North America. However, this species also occurs in the German uplands away from these main habitats, where it inhabits poorly used grasslands that generally remain unfertilised. In Hesse, only four populations in the northern Spessart area were known at the onset of a recovery programme for this species in 2003. Six new populations were found in the course of this programme. As a new record, a small population was found in the Upper Taunus region. All previously known populations in the Vogelsberg region, where this species occurred up until the 1970s, could no longer be found, but one new, small population was found. Lately, the species was also recorded in the Hessian part of the Rhön region (Barth 2008). More than half the sites where the Cold Eyebright occurs in Germany are located in Hesse, which therefore has a prominent role in the conservation of this species. It is endangered by intensification of land use (use of fertilizers, early mowing) and abandonment and forestation of low-production meadows in upland areas. The best strategy for conserving this species is to contractually ensure that farmers maintain the traditional use of meadows.Euphrasia frigida est une espèce boréo-montagnarde avec quelques stations disjointes dans les moyennes montagnes en Allemagne où elle occupe des prairies utilisées de façon extensive et en général sans engrais. Dans les montagnes de la Hesse, des spécimens récents n’ont pu être prouvés que dans le Nord du Spessart (4 en tout). Dans le cadre d’un programme d’aide à la conservation des espèces (ainsi que dans 2 investigations de FFH), on a pu constater 6 autres populations. L’indication d’une population dans le Haut-Taunus a pu être vérifiée positivement (nouvelle présence dans cette région). Les recherches dans le Vogelsberg entreprises sur les stations où l’espèce était autrefois présente jusque dans les années 70 ont été quasi négatives, mais par contre une nouvelle petite population y a été découverte. De même, l’espèce a été découverte pour la première fois dans la partie hessoise du Haut-Rhön (cf. Barth 2008). Dans l’ensemble, plus de la moitié des stations connues en Allemagne se trouvent en Hesse. Pour cette raison, le Land porte une responsabilité particulière quant à la conservation de l’espèce. Les sources principales des menaces pesant sur l’espèce sont l’utilisation intensive (emploi d’engrais et fauche trop précoce) et l’abandon de pratiques agropastorales ainsi que le reboisement des prairies à rendement limité. La garantie optimale de la conservation de l’espèce doit être obtenue par une convention portant sur l’utilisation extensive des prairies (renoncement à l’engrais, fauche après juin)

Central Tethyan platform-top hypoxia during Oceanic Anoxic Event 1a

Short-term hypoxia in epeiric water masses is a common phenomenon of modern marine environments and causes mass mortality in coastal marine ecosystems. Here, we test the hypothesis that during the early Aptian, platform-top hypoxia temporarily established in some of the vast epeiric seas of the central Tethys and caused, combined with other stressors, significant changes in reefal ecosystems. Potentially interesting target examples include time intervals characterized by the demise of lower Aptian rudist-coral communities and the establishment of microencruster facies, as previously described from the central and southern Tethys and from the proto-North Atlantic domain. These considerations are relevant as previous work has predominantly focused on early Aptian basinal anoxia in the context of Oceanic Anoxic Event (OAE) 1a, whereas the potential expansion of the oxygen minimum zone (OMZ) in coeval shallow-water environments is underexplored. Wellknown patterns in the δ13C record during OAE 1a allow for a sufficiently time-resolved correlation with previously studied locations and assignment to chemostratigraphic segments. This paper presents and critically discusses the outcome of a multi-proxy study (e.g., rare earth elements (REEs), U isotopes, and redox-sensitive trace elements) applied to lower Aptian shallow-water carbonates today exposed in the Kanfanar quarry in Istria, Croatia. These rocks were deposited on an extensive, isolated high in the central Tethys surrounded by hemipelagic basins. Remarkably, during chemostratigraphic segment C2, the depletion of redox-sensitive trace elements As, V, Mo, and U in platform carbonates, deposited in normal marine oxic waters, record the first occurrence of basinal, organic-rich sediment deposition in which these elements are enriched. During the C3 segment, seawater oxygen depletion established on the platform top as indicated by the patterns in Ce=Ce∗ and U isotopes. Shifts in redox-sensitive proxies coincide with the expansion of microencruster facies. Segment C4 witnesses the return to normal marine reefal faunas on the platform top and is characterized by patterns in redox-sensitive proxies typical of normal marine dissolved oxygen levels. It remains unclear, however, if platform-top hypoxia resulted from the expansion and upwelling of basinal, oxygen-depleted water masses or if spatially isolated, shallow hypoxic water bodies formed on the platform. Data shown here are relevant as they shed light on the driving mechanisms that control poorly understood faunal patterns during OAE 1a in the neritic realm and provide evidence on the intricate relation between basinal and platform-top water masses. © Author(s) 2019

Evaluating the role of coastal hypoxia on the transient expansion of microencruster intervals during the early Aptian

Worldwide, a growing number of modern coastal marine ecosystems are increasingly exposed to suboxic- or even anoxic conditions. Low seawater oxygen levels trigger significant ecosystem changes and may result in mass mortality of oxygen-sensitive biota. The applicability of observations from recent (anthropogenically influenced) suboxic coastal settings to fossil anoxic shallow-marine environments is, however, as yet poorly explored. The test case documented here are upper Barremian to lower Aptian strata in the Lusitanian Basin (Ericeira section, Portugal). These are characterized by the transient demise of rudist–coral communities and the rapid establishment of microencruster facies in the vacant ecological niches. The hypothesis is tested that the temporal expansion of the microencrusting organism Lithocodium aggregatum took place in response to platform-top seawater oxygen depletion. We critically discuss the outcome of a multi-proxy palaeoseawater redox approach (e.g. Rare Earth Elements (REEs), U isotopes and palaeoecology) and put the robustness of the proxies applied here to the test. This is done by considering issues with these methods in general but also emphasizing the significance of terrigenous contamination and fractionation effects. Data shown here document that evidence for coastal seawater oxygen depletion in the prelude of Oceanic Anoxic Event (OAE) 1a is lacking, and hence, anoxia was not the driving mechanism for the demise of rudist–coral ecosystems in the proto-North Atlantic platform setting studied here. In contrast, well-oxygenated early Aptian platform-top water masses are proposed for this site. Geologically short (decades to millennia) fluctuations in seawater oxygen levels cannot be excluded, however. But even if these took place, they offer no explanation for the Kyr to Myr-scale patterns discussed here. The present paper is relevant as it sheds light on the complexity of mechanisms that drive punctuated Early Cretaceous coral–rudist ecosystem turnover, and assess strengths and weaknesses of redox proxies applied to ancient shallow-marine platform carbonates. © 2020 The Authors. Lethaia published by John Wiley & Sons Ltd on behalf of Lethaia Foundatio

Radiolitid rudists: An underestimated archive for cretaceous climate reconstruction?

Rudist shells are important archives for palaeoenvironmental reconstructions in the greenhouse world of the Cretaceous. Radiolitids, a family of rudists became very abundant dwellers of the shallow marine carbonate platforms during the Cretaceous. Still, due to the complex structure of their low-Mg calcite outer shell layer, radiolitids are often deemed unsuitable for palaeoenvironmental reconstructions. The aim of this study is to present a combination of petrographic (transmitted light microscopy and cathodoluminescence microscopy) and elemental analyses (high-resolution μXRF and stable isotope) to investigate radiolitid shells for diagenetic alteration and to make them accessible as an archive for environmental conditions during the mid-Cretaceous. Four Eoradiolitites shells were analysed in detail: two right valves (RV), a left valve (LV) with an articulated RV and an isolated LV. Three shell structure types have been identified, including a non-compact, compact and celluloprismatic types. The compact structure type was identified in the LVs while the other two types were observed exclusively in the RVs. Radiolitid shell material composed of the non-compact and the compact structure types can be used as palaeoenvironmental archives as it preserved seasonal signals in both, shell growth structure and isotopic records, while celluloprismatic shell structures are less suitable for reconstructions due to diagenetic alteration. The alternation of dark and light lamellae in both valves, RV and LV, provide information on the intertidal living habitat of the shell-producing organism and its life span. Cretaceous; radiolitid rudists; petrographic and rlemental analyses; right and left valves; palaeoenvironmental reconstructio

DNA binds to a specific site of the adhesive blood-protein von Willebrand factor guided by electrostatic interactions.

Neutrophils release their intracellular content, DNA included, into the bloodstream to form neutrophil extracellular traps (NETs) that confine and kill circulating pathogens. The mechanosensitive adhesive blood protein, von Willebrand Factor (vWF), interacts with the extracellular DNA of NETs to potentially immobilize them during inflammatory and coagulatory conditions. Here, we elucidate the previously unknown molecular mechanism governing the DNA-vWF interaction by integrating atomistic, coarse-grained, and Brownian dynamics simulations, with thermophoresis, gel electrophoresis, fluorescence correlation spectroscopy (FCS), and microfluidic experiments. We demonstrate that, independently of its nucleotide sequence, double-stranded DNA binds to a specific helix of the vWF A1 domain, via three arginines. This interaction is attenuated by increasing the ionic strength. Our FCS and microfluidic measurements also highlight the key role shear-stress has in enabling this interaction. Our simulations attribute the previously-observed platelet-recruitment reduction and heparin-size modulation, upon establishment of DNA-vWF interactions, to indirect steric hindrance and partial overlap of the binding sites, respectively. Overall, we suggest electrostatics-guiding DNA to a specific protein binding site-as the main driving force defining DNA-vWF recognition. The molecular picture of a key shear-mediated DNA-protein interaction is provided here and it constitutes the basis for understanding NETs-mediated immune and hemostatic responses