296 research outputs found

    The BIOKLIM project: biodiversity research between climate change and wilding in a temperate montane forest : the conceptual framework

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    To understand the rapid rate of change in global biodiversity, it is necessary to analyse the present condition of ecosystems and to elucidate relationships of species to their environment. The BIOKLIM Project (Biodiversity and Climate Change Project) is intended to close this gap in our knowledge of montane and high montane forests of Central European low mountain ranges, one of the most threatened mixed montane systems worldwide. The Bavarian Forest National Park is characterised by its altitude range of ca. 800 m and a strongly developed gradient of forest structure. Relicts of old growth forests (areas of former local nature reserves) and dead stands, mostly killed by bark beetles, are accompanied by widely varying levels of woody debris and light. The gradients comprise a wide range of abiotic and forest structure factors, making the study area well suited for a multidisciplinary investigation of biodiversity. Unconstrained ordination (CA) of six taxa (vascular plants, wood inhabiting fungi, birds, carabids, spiders and molluscs) indicate the altitudinal gradient to be the main driver for distribution patterns of species assemblages. Objectives, structure, study design and data sampling of the BIOKLIM Project are described in detail. We set up 293 sampling plots along four main straight transects following the altitudinal gradient. All abiotic and stand structure data regarded as relevant are available for each plot. Vascular plants, wood inhabiting fungi and birds were sampled or mapped on all 293 plots. For the other 22 investigated taxa we used subsamples pre-stratified according to the sampling methods. The necessity of dealing with spatial autocorrelation, arising from sampling along linear transects, is described. Finally, study approach of our biodiversity project is compared with others involving altitudinal gradients. Worldwide, only a few multidisciplinary biodiversity studies have been previously conducted on long altitudinal gradients. However, in most cases sampling techniques were similar to ours, which allows comparison of results between continents. Keywords: Climate Change, Biodiversity, species-environment relationshipsUm die rasante VerĂ€nderung globaler BiodiversitĂ€t zu verstehen, ist es erforderlich, den gegenwĂ€rtigen Zustand von Ökosystemen zu analysieren und die ZusammenhĂ€nge zwischen Arten und deren Umwelt aufzulösen. Das BIOKLIMProjekt (BiodiversitĂ€t und Klima Projekt) hat zum Ziel, diese WissenslĂŒcken fĂŒr WĂ€lder montaner und hochmontaner Mittelgebirge zu schließen. Der Nationalpark Bayerischer Wald ist neben dem Höhengradient (ca. 800 m) durch einen starken Strukturgradient geprĂ€gt. Dieser resultiert aus Restvorkommen sehr alter BestĂ€nde (ehem. Naturschutzgebiete) sowie dem Wirken des BorkenkĂ€fers seit ca. zwei Jahrzehnten und einem dadurch verbundenen z. T. sehr hohen Totholzvorrat. Die Gradienten umfassen eine breite Spanne von abiotischen Faktoren und Bestandesstrukturen und machen den Nationalpark zu einem gut geeigneten Untersuchungsgebiet fĂŒr interdisziplinĂ€re BiodiversitĂ€tsforschung. Korrespondenzanalysen (CA) fĂŒr 6 taxonomische Gruppen (GefĂ€ĂŸpflanzen, Holzpilze, Vögel, LaufkĂ€fer, Spinnen und Mollusken) machen die starke AbhĂ€ngigkeit der Artengruppen vom Höhengradienten deutlich. Es werden detailliert die Zielsetzungen, Projektaufbau, das Untersuchungsdesign sowie die Erfassungsmethoden des BIOKLIM-Projektes beschrieben. 293 Probepunkte wurden entlang von 4 Transekten, welche dem Höhengradienten folgen, eingerichtet. Zu jedem Probekreis stehen alle als relevant erachteten Daten zur Abiotik und Bestandesstruktur zur VerfĂŒgung. GefĂ€ĂŸpflanzen, Holzpilze und Vögel wurden auf allen 293 Probepunkten erfasst. FĂŒr die anderen 22 untersuchten Artengruppen wurde in AbhĂ€ngigkeit von der Methode ein stratifiziertes Design gewĂ€hlt. LösungsansĂ€tze zum Umgang mit Autokorrelation, die durch die Anordnung von Probekreisen entlang von Linien (Transekte) bedingt ist, werden dargestellt. Schließlich wird das BIOKLIM-Projekt mit den wenigen weltweiten BiodiversitĂ€tsprojekten verglichen und diskutiert. In den meisten FĂ€llen sind die Erhebungsmethoden Ă€hnlich, sodass Vergleiche der Ergebnisse zwischen verschiedenen Kontinenten möglich werden. SchlĂŒsselwörter: Klimawandel, BiodiversitĂ€t, Arten-Umwelt-Beziehun

    Sheet plasmons in modulated graphene on Ir(111)

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    The sheet plasmon of graphene on Ir(111) was investigated in this paper by means of high-resolution electron energy loss spectroscopy. The perfect lateral coordination of sp2-hybridized C atoms on a large scale is manifested by brilliant moirĂ© diffraction images. However, the modulation of the graphene films caused by hybridization at the interface limits the lifetimes of the collective excitation modes. This modulation within the films can be lowered owing to intercalation of Na. Linear dispersion was found, but surprisingly the overall slope of the dispersion is not dependent on the chemical potential within the graphene films. The dispersion measured for graphene on Ir(111) is almost identical to that measured on SiC(0001), although the carrier densities differ by two orders of magnitude. This contradicts the model that the relevant carrier density for a two-dimensional plasmon is given by (2π) -1k2 F © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.DF

    Phenolic compound abundance in Pak choi leaves is controlled by salinity and dependent on pH of the leaf apoplast

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    Onset of salinity induces the pH of the leaf apoplast of Pak choi transiently to increase over a period of 2 to 3 hr. This pH event causes protein abundances in leaves to increase. Among them are enzymes that are key for the phenylpropanoid pathway. To answer the questions whether this short-term salt stress also influences contents of the underlying phenylpropanoids and for clarifying as to whether the apoplastic pH transient plays a role for such a putative effect, Pak choi plants were treated with 37.5 mM CaCl2 against a non-stressed control. A third experimental group, where the leaf apoplast of plants treated with 37.5 mM CaCl2, was clamped in the acidic range by means of infiltration of 5 mM citric acid/sodium citrate (pH 3.6), enabled validation of pH-dependent effects. Microscopy-based live cell imaging was used to quantify leaf apoplastic pH in planta. Phenolics were quantified shortly after the formation of the leaf apoplastic pH transient by means of HPLC-DAD-ESI-MS. Results showed that different phenolic compounds were modulated at 150 and 200 min after the onset of chloride salinity. A pH-independent reduction in phenolic acid abundance as well as an accumulation of phenolic acid:malate conjugates was quantified after 200 min of salt stress. However, at 150 min after the onset of salt stress, flavonoids were significantly reduced by salinity in a pH-dependent manner. These results provided a strong indication that the pH of the apoplast is a relevant component for the short-term metabolic response to chloride salinity.BMBF research grantDeutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Peer Reviewe

    Wissensaustausch zwischen Forschung und Praxis erfolgreich gestalten

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    Um die gesellschaftliche Transformation zu gestalten, wird der Austausch von Wissen zwischen Wissenschaft und Praxis immer wichtiger. Dieser Artikel benennt Prinzipien, Kompetenzen und Rahmenbedingungen fĂŒr erfolgreichen Wissensaustausch

    Matrix Effects on Photoluminescence and Oxygen Sensitivity of a Molecular Ruby

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    The molecular ruby analogue [Cr(ddpd)2]3+ (ddpd=N,N’‐dimethyl‐N,N’‐dipyridine‐2‐ylpyridine‐2,6‐diamine) exhibits near infrared (NIR) emission with a high photoluminescence (PL) quantum yield ΊPL of 11 % and a lifetime of 898 Όs in deaerated water at room temperature. While ligand‐based control of the photophysical properties has received much attention, influences of the counter anions and microenvironment are still underexplored. In this study, the luminescence properties of the molecular ruby were systematically examined for the counter anions Cl−, Br−, [BF4]−, [PF6]−, [BPh4]−, and [BArF24]− in acetonitrile (MeCN) solution, in crystals, and embedded into polystyrene nanoparticles (PSNP). Stern‐Volmer analyses of the oxygen quenching studies in the intensity and lifetime domain showed the highest oxygen sensitivity of the complexes with the counter anions of [BF4]− and [BArF24]−, which also revealed the longest luminescence lifetimes. Embedding [Cr(ddpd)2][PF6]3 in PSNPs and shielding with poly(vinyl alcohol) yields a strongly NIR‐emissive oxygen‐insensitive material with a record ΊPL of 15.2 % under ambient conditions

    Impact of climate change on waterborne infections and intoxications

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    Progressive climate change holds the potential for increasing human health risks from waterborne infections and intoxications, e. g. through an increase in pathogen concentrations in water bodies, through the establishment of new pathogens or through possible changes in pathogen properties. This paper presents some examples of potential impacts of climate change in Germany. Non-cholera Vibrio occur naturally in seawater, but can proliferate significantly in shallow water at elevated temperatures. In the case of Legionella, climate change could lead to temporary or longer-term increased incidences of legionellosis due to the combination of warm and wet weather. Higher temperatures in piped cold water or lower temperatures in piped hot water may also create conditions conducive to higher Legionella concentrations. In nutrient-rich water bodies, increased concentrations of toxigenic cyanobacteria may occur as temperatures rise. Heavy rainfall following storms or prolonged periods of heat and drought can lead to increased levels of human pathogenic viruses being washed into water bodies. Rising temperatures also pose a potential threat to human health through pathogens causing mycoses and facultatively pathogenic micro-organisms: increased infection rates with non-tuberculous mycobacteria or fungi have been documented after extreme weather events

    Solvent-dependent self-assembly of an amphiphilic copper(II) complex with bulky head groups

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    The aggregation behavior of an amphiphilic copper(II) complex was studied in solution by means of UV-Vis and EPR spectroscopy. While dilute solutions in polar media do not give indication of relevant intermolecular interactions, concentrated solutions in nonpolar media clearly do not reflect the molecular properties of [CuL] (H2_2L: N2_2O2_2 ligand of the JĂ€ger-type with bulky head-group and long alkoxy tailing). Massive broadening of EPR-lines is prevalent in non-polar media, such as n-heptane and iso-octane. In combination with DFT-modelling, the solvent-dependence of the EPR response (line widths and Cu-hyperfine coupling) could be associated with the formation of oligomers with weak anti-ferromagnetically coupled copper centers. Weak anti-ferromagnetic coupling becomes evident also by SQUID magnetometry at T<10 K of solid samples of [CuL]. The tendency towards supramolecular aggregation is unequivocally shown by electron microscopy of dried (TEM) and frozen samples (cryo-TEM). While the former approach gives evidence of the formation of extended 2D sheet-like structures with extensions on the micrometer scale, the latter technique identifies the formation of 1D thread-like structures with lengths of several hundred nanometers

    Near-IR to Near-IR Upconversion Luminescence in Molecular Chromium Ytterbium Salts

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    Upconversion photoluminescence in hetero-oligonuclear metal complex architectures featuring organic ligands is an interesting but still rarely observed phenomenon, despite its great potential from a basic research and application perspective. In this context, a new photonic material consisting of molecular chromium(III) and ytterbium(III) complex ions was developed that exhibits excitation-power density-dependent cooperative sensitization of the chromium-centered(2)E/(2)T(1)phosphorescence at approximately 775 nm after excitation of the ytterbium band(2)F(7/2)->(2)F(5/2)at approximately 980 nm in the solid state at ambient temperature. The upconversion process is insensitive to atmospheric oxygen and can be observed in the presence of water molecules in the crystal lattice

    Quality of life in the follow-up of uveal melanoma patients after CyberKnife treatment

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    To assess quality of life in uveal melanoma patients within the first and second year after CyberKnife radiosurgery. Overall, 91 uveal melanoma patients were evaluated for quality of life through the Short-form (SF-12) Health Survey at baseline and at every follow-up visit over 2 years after CyberKnife radiosurgery. Statistical analysis was carried out using SF Health Outcomes Scoring Software and included subgroup analysis of patients developing secondary glaucoma and of patients maintaining a best corrected visual acuity (BCVA) of the treated eye of 0.5 log(MAR) or better. Analysis of variance, Greenhouse-Geisser correction, Student's t-test, and Fisher's exact test were used to determine statistical significance. Physical Functioning (PF) and Role Physical (RP) showed a significant decrease after CyberKnife radiosurgery, whereas Mental Health (MH) improved (P=0.007, P<0.0001 and P=0.023). MH and Social Functioning (SF) increased significantly (P=0.0003 and 0.026) in the no glaucoma group, MH being higher compared with glaucoma patients (P=0.02). PF and RP were significantly higher in patients with higher BCVA at the second follow-up (P=0.02). RP decreased in patients with BCVA<0.5 log(MAR) (P=0.013). Vitality (VT) increased significantly in patients whose BCVA could be preserved (P=0.031). Neither tumor localization nor size influenced the development of secondary glaucoma or change in BCVA. Although PF and RP decreased over time, MH improved continuously. Prevention of secondary glaucoma has a significant influence on both SF and MH, whereas preservation of BCVA affects VT. Emotional stability throughout follow-up contributes positively toward overall quality of life. CyberKnife radiosurgery may contribute to attenuation of emotional distress in uveal melanoma patients
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