900 research outputs found
Impact of change in climate and policy from 1988 to 2007 on environmental and microbial variables at the time series station Boknis Eck, Baltic Sea
Phytoplankton and bacteria are sensitive indicators of environmental change. The temporal development of these key organisms was monitored from 1988 to the end of 2007 at the time series station Boknis Eck in the western Baltic Sea. This period was characterized by the adaption of the Baltic Sea ecosystem to changes in the environmental conditions caused by the conversion of the political system in the southern and eastern border states, accompanied by the general effects of global climate change. Measured variables were chlorophyll, primary production, bacteria number, -biomass and -production, glucose turnover rate, macro-nutrients, pH, temperature and salinity. Negative trends with time were recorded for chlorophyll, bacteria number, bacterial biomass and bacterial production, nitrate, ammonia, phosphate, silicate, oxygen and salinity while temperature, pH, and the ratio between bacteria numbers and chlorophyll increased. Strongest reductions with time occurred for the annual maximum values, e.g. for chlorophyll during the spring bloom or for nitrate during winter, while the annual minimum values remained more stable. In deep water above sediment the negative trends of oxygen, nitrate, phosphate and bacterial variables as well as the positive trend of temperature were similar to those in the surface while the trends of salinity, ammonia and silicate were opposite to those in the surface. Decreasing oxygen, even in the surface layer, was of particular interest because it suggested enhanced recycling of nutrients from the deep hypoxic zones to the surface by vertical mixing. The long-term seasonal patterns of all variables correlated positively with temperature, except chlorophyll and salinity. Salinity correlated negatively with all bacterial variables (as well as precipitation) and positively with chlorophyll. Surprisingly, bacterial variables did not correlate with chlorophyll, which may be inherent with the time lag between the peaks of phytoplankton and bacteria during spring. Compared to the 20-yr averages of the environmental and microbial variables, the strongest negative deviations of corresponding annual averages were measured about ten years after political change for nitrate and bacterial secondary production (~ â60%), followed by chlorophyll (â50%) and bacterial biomass (â40%). Considering the circulation of surface currents in the Baltic Sea we interpret the observed patterns of the microbial variables at the Boknis Eck time series station as a consequence of the improved management of water resources after 1989 and â to a minor extent â the trends of the climate variables salinity and temperature
How strange are compact star interiors ?
We discuss a Nambu--Jona-Lasinio (NJL) type quantum field theoretical
approach to the quark matter equation of state with color superconductivity and
construct hybrid star models on this basis. It has recently been demonstrated
that with increasing baryon density, the different quark flavors may occur
sequentially, starting with down-quarks only, before the second light quark
flavor and at highest densities also the strange quark flavor appears. We find
that color superconducting phases are favorable over non-superconducting ones
which entails consequences for thermodynamic and transport properties of hybrid
star matter. In particular, for NJL-type models no strange quark matter phases
can occur in compact star interiors due to mechanical instability against
gravitational collapse, unless a sufficiently strong flavor mixing as provided
by the Kobayashi-Maskawa-'t Hooft determinant interaction is present in the
model. We discuss observational data on mass-radius relationships of compact
stars which can put constraints on the properties of dense matter equation of
state.Comment: 7 pages, 2 figures, to appear in the Proceedings of the International
Conference SQM2009, Buzios, Rio de Janeiro, Brazil, Sep.27-Oct.2, 200
Differentiation of plant derived organic matter in soil, loess and rhizoliths based on n-alkane molecular proxies
Assessment of pulmonary antibodies with induced sputum and bronchoalveolar lavage induced by nasal vaccination against Pseudomonas aeruginosa: a clinical phase I/II study
<p>Abstract</p> <p>Background</p> <p>Vaccination against <it>Pseudomonas aeruginosa </it>is a desirable albeit challenging strategy for prevention of airway infection in patients with cystic fibrosis. We assessed the immunogenicity of a nasal vaccine based on the outer membrane proteins F and I from <it>Pseudomonas aeruginosa </it>in the lower airways in a phase I/II clinical trial.</p> <p>Methods</p> <p>N = 12 healthy volunteers received 2 nasal vaccinations with an OprF-OprI gel as a primary and a systemic (n = 6) or a nasal booster vaccination (n = 6). Antibodies were assessed in induced sputum (IS), bronchoalveolar lavage (BAL), and in serum.</p> <p>Results</p> <p>OprF-OprI-specific IgG and IgA antibodies were found in both BAL and IS at comparable rates, but differed in the predominant isotype. IgA antibodies in IS did not correlate to the respective serum levels. Pulmonary antibodies were detectable in all vaccinees even 1 year after the vaccination. The systemic booster group had higher IgG levels in serum. However, the nasal booster group had the better long-term response with bronchial antibodies of both isotypes.</p> <p>Conclusion</p> <p>The nasal OprF-OprI-vaccine induces a lasting antibody response at both, systemic and airway mucosal site. IS is a feasible method to non-invasively assess bronchial antibodies. A further optimization of the vaccination schedule is warranted.</p
Biogeochemie von Phosphat im Unterboden am Beispiel deutscher DauerdĂŒngungsversuche
Unterböden von Ackerstandorten verfĂŒgen ĂŒber groĂe VorrĂ€te an Phosphat (P), allerdings ist nach wie vor unklar, ob, in welchem Umfang und unter welchen Bedingungen diese NĂ€hrstoffreserven im Unterboden zur ErnĂ€hrung unserer Ackerkulturen beitragen. Wir vermuten, dass einerseits langjĂ€hrige P-Limitierung dazu fĂŒhren kann, dass mehr P aus dem Unterboden aufgenommen wird, dass aber andererseits die ZugĂ€nglichkeit zu P-Reserven im Unterboden auch abhĂ€ngig ist von der Versorgung mit anderen NĂ€hrstoffen, wie z.B. Stickstoff (N) und Kalium (K).
Um diese Hypothesen zu testen, beprobten wir unter anderem zwei Statische NĂ€hrstoffmangelversuche in Thyrow (Brandenburg) und GieĂen (Hessen). Wir entnahmen Bodenproben bis in 100 cm Tiefe, aus Varianten, die seit ĂŒber 60 Jahren entweder NPK, NK oder PK DĂŒngung erhalten haben. FĂŒr diese Proben bestimmten wir die P Pools nach Hedley et al. (1), sowie die Sauerstoffisotopie des Phosphats nach Extraktion mit 1M HCl (ÎŽ18OHCl P), welches eine Differenzierung in primĂ€re und sekundĂ€re (d.h. nach vorherigem biologischem Cycling neu ausgefĂ€llte) P-Minerale ermöglicht. An beiden Standorten beobachteten wir, dass in den NK-gedĂŒngten Varianten die VorrĂ€te der labilen P Pools aus dem Hedleyâschen Extraktionsschema im Unterboden (30 â 100 cm) 10 â 60% geringer waren als in den NPK-gedĂŒngten Varianten. Die VorrĂ€te an HCl P in den NK-Varianten waren jedoch v.a. in Thyrow bis zu 70% höher, wĂ€hrend gleichzeitg die ÎŽ18OHCl P Werte deutlich niedriger waren als in den NPK-Varianten. Diese niedrigeren Isotopensignaturen deuten auf hauptsĂ€chlich primĂ€re P-Minerale hin, sodass wir unsere Annahme von höherem P-Cycling im Unterboden bei Mangel im Oberboden widerrufen mĂŒssen. In den PK-gedĂŒngten Varianten beobachteten wir, dass die VorrĂ€te an labilem P im Unterboden 117% (Thyrow) und 22% (GieĂen) gröĂer waren als in der NPK-Variante. Dies stĂŒtzt unsere zweite Annahme von einer Limitierung der P-Aufnahme aus dem Unterboden aufgrund des Mangels an anderen NĂ€hrstoffen, allerdings ergaben sich hier keine klaren Auswirkungen auf die ÎŽ18OHCl P Signatur des Phosphats. Im Folgenden sollen diese Beobachtungen nun an weiteren Standorten und unter weiteren Einflussparametern getestet werden. Zusammenfassend zeigen jedoch schon unsere bisherigen Ergebnisse, dass die effiziente Ausnutzung von P-Reserven im Unterboden nur unter optimaler NĂ€hrstoffversorgung im Oberboden erfolgt
Clinical and epidemiological profile of female blood donors with positive serology for viral hepatitis B
Characterization of the U.S. Gulf of Mexico and South Atlantic penaeid and rock shrimp fisheries based on observer data
In July 2007, a mandatory Federal observer program was implemented to characterize the U.S. Gulf of Mexico penaeid shrimp (Farfantepenaeus aztecus, F. duorarum, and Litopenaeus setiferus) fishery. In June 2008, the program expanded to include the South Atlantic penaeid and rock shrimp, Sicyonia spp., fisheries. Data collected from 10,206 tows during 5,197 sea days of observations were analyzed by geographical area and target species. The majority of tows (~70%) sampled were off the coasts of Texas and Louisiana. Based on total hours towed, the highest concentrated effort occurred off South Texas and southwestern Florida. Gear information, such as net characteristics, bycatch reduction devices, and turtle excluder devices were fairly consistent among areas and target species. By species categories, finfish comprised the majority (â„57%) of the catch composition in the Gulf of Mexico and South Atlantic penaeid shrimp fisheries, while in the South Atlantic rock shrimp fishery the largest component (41%) was rock shrimp. Bycatch to shrimp ratios were lower than reported in previous studies for the Gulf of Mexico penaeid shrimp fishery. These decreased ratios may be attributed to several factors, notably decreased shrimp effort and higher shrimp catch per unit of effort (CPUE) in recent years. CPUE density surface plots for several species of interest illustrated spatial differences in distribution. Hot Spot Analyses for shrimp (penaeid and rock) and bycatch species identified areas with significant clustering of high or low CPUE values. Spatial and temporal distribution of protected species interactions were documented
Diazoxide attenuates autoimmune encephalomyelitis and modulates lymphocyte proliferation and dendritic cell functionality
Activation of mitochondrial ATP-sensitive potassium (KATP) channels is postulated as an effective mechanism to confer cardio and neuroprotection, especially in situations associated to oxidative stress. Pharmacological activation of these channels inhibits glia-mediated neuroinflammation. In this way, diazoxide, an old-known mitochondrial KATP channel opener, has been proposed as an effective and safe treatment for different neurodegenerative diseases, demonstrating efficacy in different animal models, including the experimental autoimmune encephalomyelitis (EAE), an animal model for Multiple Sclerosis. Although neuroprotection and modulation of glial reactivity could alone explain the positive effects of diazoxide administration in EAE mice, little is known of its effects on the immune system and the autoimmune reaction that triggers the EAE pathology. The aim of the present work was to study the effects of diazoxide in autoimmune key processes related with EAE, such as antigen presentation and lymphocyte activation and proliferation. Results show that, although diazoxide treatment inhibited in vitro and ex-vivo lymphocyte proliferation from whole splenocytes it had no effect in isolated CD4(+) T cells. In any case, treatment had no impact in lymphocyte activation. Diazoxide can also slightly decrease CD83, CD80, CD86 and major histocompatibility complex class II expression in cultured dendritic cells, demonstrating a possible role in modulating antigen presentation. Taken together, our results indicate that diazoxide treatment attenuates autoimmune encephalomyelitis pathology without immunosuppressive effect
- âŠ