Bewertung und Entwicklung künstlicher Stehgewässer im Biosphärenreservat Pfälzerwald

The survival of the approximately 1,000 artificial ponds in the Pfälzerwald (Palatinate Forest) biosphere reserve is endangered as they continue to be abandoned, but a large number of them have conservation and historical value. An overall management concept is needed as the high costs for restoration and the requirements of the EU Water Framework Directive regarding river continuity will make it impossible to maintain all of the ponds. Most of the ponds are migration barriers for fish and aquatic invertebrates. The assessment methods presented here are based on readily available data for the evaluation of the ecological and cultural-historical importance of the ponds, their implications within the landscape, and their (often negative) impact on stream ecology. The assessment of the condition of the ponds’ manmade structures leads to conclusions about the urgency for action. The assessment classes are linked with recommendations for action. In the synopsis of all assessments, management concepts emerge for the individual ponds, and priority lists of ponds can be generated that point out where actions are preferential.Aufgrund zunehmender Nutzungsaufgabe an den etwa 1.000 künstlichen Stehgewässern im Biosphärenreservat Pfälzerwald und ihrer gleichzeitig oft hohen naturschutzfachlichen bzw. kulturhistorischen Bedeutung ist ein Managementkonzept notwendig geworden. Dem Erhalt der Anlagen stehen hohe Sanierungskosten sowie die Anforderungen der EU-Wasserrahmenrichtlinie, für eine biologische Durchgängigkeit der Fließgewässer zu sorgen, entgegen. Die meisten Anlagen stellen nämlich unüberwindliche Wanderbarrieren dar. Die vorgestellten Bewertungsverfahren, basierend auf einfach zu erhebenden Merkmalen, beurteilen die ökologische und die kulturhistorische Bedeutung der Anlagen, die Bedeutung für das Landschaftsbild sowie ihre (negativen) Auswirkungen auf das Fließgewässersystem. Die Bewertung des baulichen Zustands ergibt Aussagen über die Dringlichkeit des Handelns. Die einzelnen Bewertungsklassen sind mit Handlungsempfehlungen verknüpft. In der Zusammenschau der einzelnen Empfehlungen leiten sich Maßnahmen für die einzelnen Gewässer ab sowie Priorisierungen von Teichen, an denen vorrangig Handlungen erfolgen sollen

Crystalline and disordered state of poly(dihexylsilylene) copolymers

A systematic comparison of random copolymers, derived from poly(dihexylsilylene) (PDHS) by incorporation of monomeric units with shorter unbranched alkyl side chains, has been carried out based on calorimetry, variable temperature UV spectroscopy, and 29Si MAS (magic angle spinning) solid state NMR investigations. Also, hexylmethylsilylene units and branched monomers have been copolymerized. Up to 10% comonomer with shorter linear side chains (i. e., pentyl to propyl) could be incorporated into PDHS without impeding the all-trans order of the crystalline phase. In this case, the UV absorption maximum of the crystalline low-temperature phase was affected only slightly according to the length and fraction of the comonomer side chains. A less ordered crystal structure (λmax = 345-355 nm) was observed when the content of comonomers with shorter side chains was about 20%. Yet, all these materials form conformationally disordered mesophases. A clear disordering transition and corresponding thermochromism was not observed any more when 50% of propyl side chains were incorporated. The order of the crystalline and the mesophase is also strongly perturbed if only a small fraction (4%) of the side chains are branched at C2

Historically unprecedented global glacier decline in the early 21st century

Observations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass-balance data relating to the impact that glaciers exercise on global sea-level fluctuations or on regional runoff. In this study we provide an overview and analysis of the main observational datasets compiled by the World Glacier Monitoring Service (WGMS). The dataset on glacier front variations (∼42 000 since 1600) delivers clear evidence that centennial glacier retreat is a global phenomenon. Intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the Little Ice Age (or Holocene). Glaciological and geodetic observations (∼5200 since 1850) show that the rates of early 21st-century mass loss are without precedent on a global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. This strong imbalance implies that glaciers in many regions will very likely suffer further ice loss, even if climate remains stable

Hydrosilylation of 1-alkenes with dichlorosilane

Symmetrically and unsymmetrically substituted diorganodichlorosilanes have been prepared by hydrosilylation with dichlorosilane using two different platinum catalysts, i.e., hexachloroplatinic acid (Speier's catalyst) and a platinum cyclovinylmethylsiloxane complex. Hydrosilylation of unsubstituted 1-alkenes proved to be very efficient, yielding anti-Markonikov substituted di-n-alkyldichlorosilanes. However, no reaction was observed when electron-deficient 1-alkenes were used. Octacarbonyldicobalt enabled formation of the monoadduct of 1H,1H,2H-perfluoro-1-hexene with dichlorosilane, which was employed in a second hydrosilylation of the olefin. Thus, the anti-Markovnikov diadduct was obtained in 40% overall yield. The two-step synthesis has also been applied successfully to obtain unsymmetrically substituted diorganodichlorosilanes containing nitrile and ether groups

Order and thermochromism of poly(di-n-alkyl)silane copolymers

A series of poly(di-n-alkyl)silane copolymers derived from Poly(di-n-hexyl)silane, PDHS, was prepared. Mesomorphic phase transitions of these copolymers depend on fraction as well as on the size of the comonomers. DSC and temperature dependent UV-spectroscopy were employed to study the effect of constitutional disorder on the length of all-trans σ-conjugated Si---Si catenated chromophores

N‑Oxide Polyethers as Kinetic Hydrate Inhibitors: Side Chain Ring Size Makes the Difference

The formation of gas hydrates in flow lines is one of the most severe problems for flow assurance in the gas and oil industry. Developing effective kinetic hydrate inhibitors (KHIs) to avoid the problem of gas hydrate formation has attracted widespread attention. In this study, a series of poly(glycidyl amine N-oxide)s (PGAOs) with 5–7-membered rings as side chains, poly(pyrrolidine glycidyl amine N-oxide)s (PPyrGAOs), poly(piperidine glycidyl amine N-oxide)s (PPiGAOs), and poly(azepane glycidyl amine N-oxide)s (PAzGAOs), with varying molecular weights, have been synthesized. The KHI performance of these glycidyl amine N-oxide polyethers has been evaluated in high-pressure rocking cells with the synthetic natural gas (SNG) mixture. The PGAOs with lower molecular weights gave better KHI performance, and at 2500 ppm, the best one gave an average To value of 9.8 °C (ΔT = 10.4 °C), which is on a par with polyvinylcaprolactam (PVCap). Even in high concentration of brine solution, none of the PGAOs showed a cloud point up to 95 °C. Employing molecular weights of around 4 kg/mol, the KHI performance of the PGAOs follows the following trend, correlating with the ring size: PPyrGAO < PPiGAO < PAzGAO. However, at higher molecular weight, the ring size of the pendant group did not affect the KHI performance of the PGAOs. PPiGAO with the smaller piperidine ring groups gave better inhibition effect than PAzGAO when the molecular weights were at approximately 8 kg/mol. In addition, the KHI performance of one of the best PAzGAOs was tested in the concentration range from 1000 to 5000 ppm, and an increase of the KHI performance with increasing concentration of polymer was observed. The amine N-oxide functional group is critical for the KHI performance of these polymers, as poly(pyrrolidine glycidyl amine)s (PPyrGAs) and poly(azepane glycidyl amine)s (PAzGAs) with amine groups instead of the N-oxide gave a negligible inhibitory effect.publishedVersio

The minimal important difference of the hospital anxiety and depression scale in patients with chronic obstructive pulmonary disease

BACKGROUND: Interpretation of the Hospital Anxiety and Depression Scale (HADS), commonly used to assess anxiety and depression in COPD patients, is unclear. Since its minimal important difference has never been established, our aim was to determine it using several approaches. METHODS: 88 COPD patients with FEV1 /= 0.5 we performed linear regression analyses to predict the minimal important difference from the anchors. As distribution-based approach we used the Effect Size approach. RESULTS: Based on CRQ emotional function and mastery domain as well as on total scores, the minimal important difference was 1.41 (95% CI 1.18-1.63) and 1.57 (1.37-1.76) for the HADS anxiety score and 1.68 (1.48-1.87) and 1.60 (1.38-1.82) for the HADS total score. Correlations of the HADS depression score and CRQ domain and Feeling Thermometer scores were < 0.5. Based on the Effect Size approach the MID of the HADS anxiety and depression score was 1.32 and 1.40, respectively. CONCLUSION: The minimal important difference of the HADS is around 1.5 in COPD patients corresponding to a change from baseline of around 20%. It can be used for the planning and interpretation of trials

Highly oriented poly(di-n-alkylsilylene) films on oriented PTFE substrates

Highly oriented polysilylene layers have potential applications in electrophotography, nonlinear optics, display fabrication, and microlithography. The preparation of such layers by crystallization on a highly oriented PTFE substrate is reported, and their assessment by optical birefringence, electron diffraction and dichroic infrared experiments described. Why this orientation technique works is not yet clear, especially as it can be applied to poly(di-n-alkylsilylen)s with different crystal structures. Several possible underlying mechanisms are discussed

Sectorwise assessment of glacial lake outburst flood danger in the Indian Himalayan region

Climate change and associated glacier recession have led to the formation of new glacial lakes and the expansion of existing ones across the Himalayas. Many pose a potential glacial lake outburst flood (GLOF) threat to downstream communities and infrastructure. In this paper, 4418 glacial lakes in the Indian Himalayan Region and 636 transboundary lakes are analyzed. We consider hazard, exposure, and integrated danger levels using robust geographic information system-based automated approaches. The hazard level of lakes was estimated based on the potential for avalanches to strike the lake, size of the lake and its upstream watershed, and distal slope of its dam. Exposure levels were calculated by intersecting cropland, roads, hydropower projects, and the human population with potential GLOF trajectories. Then, GLOF danger was determined as a function of hazard and exposure. The study demonstrates that Jammu and Kashmir (JK) is potentially the most threatened region in terms of total number of very high and high danger lakes (n = 556), followed by Arunachal Pradesh (AP) (n = 388) and Sikkim (SK) (n = 219). Sectorwise, JK faces the greatest GLOF threat to roads and population, whereas the threat to cropland and hydropower is greatest in AP and SK, respectively. Transboundary lakes primarily threaten AP and, to a lesser extent, Himachal Pradesh (HP). For Uttarakhand (UK), the impacts of potential future glacial lakes, expected to form during rapid ongoing glacier recession because of climate change, are explored. Finally, a comparison of current results with previous studies suggests that 13 lakes in SK, 5 in HP, 4 in JK, 2 in UK, and 1 in AP are of highest priority for local investigation and potential risk reduction measures. Current results are of vital importance to policymakers, disaster management authorities, and the scientific community