132 research outputs found

    An integrated compilation of data sources for the development of a marine protected area in the Weddell Sea

    Get PDF
    The Southern Ocean may contribute a considerable amount to the proposed global network of marine protected areas (MPAs) that should cover about 10 % of the world’s oceans in 2020. In the Antarctic, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is responsible for this task, and currently Germany leads a corresponding scientific evaluation of the wider Weddell Sea region. Compared to other marine regions within the Southern Ocean, the Weddell Sea is exceptionally well investigated. A tremendous amount of data and information has been produced over the last 4 decades. Here, we give a systematic overview of all data sources collected in the context of the Weddell Sea MPA planning process. The compilation of data sources is comprised of data produced by scientists and institutions from more than 20 countries that were either available within our institutes, downloaded via data portals or transcribed from the literature. It is the first compilation for this area that includes abiotic data, such as bathymetry and sea ice, and ecological data from zooplankton, zoobenthos, fish, birds and marine mammals. All data layer products based on this huge compilation of environmental and ecological data are available from the data publisher PANGAEA via the six persistent identifiers at https://doi.org/10.1594/PANGAEA.899595 (Pehlke and Teschke, 2019), https://doi.org/10.1594/PANGAEA.899667 (Teschke et al., 2019a), https://doi.org/10.1594/PANGAEA.899645 (Teschke et al., 2019b), https://doi.org/10.1594/PANGAEA.899591 (Teschke et al., 2019c), https://doi.org/10.1594/PANGAEA.899520 (Pehlke et al., 2019a) and https://doi.org/10.1594/PANGAEA.899619 (Pehlke et al., 2019b). This compilation of data sources including the final data layer products will serve future research and monitoring well beyond the current MPA development process

    Phytoplankton stimulation in frontal regions of Benguela Upwelling filaments by internal factors

    Get PDF
    Filaments are intrusions of upwelling water into the sea, separated from the surrounding water by fronts. Current knowledge explains the enhanced primary production and phytoplankton growth found in frontal areas by external factors like nutrient input. The question is whether this enhancement is also caused by intrinsic factors, i.e., simple mixing without external forcing. In order to study the direct effect of frontal mixing on organisms, disturbing external influx has to be excluded. Therefore, mixing was simulated by joining waters originating from “inside” and “outside” the filament in mesocosms (“tanks”). These experiments were conducted during two cruises in the northern Benguela upwelling system in September 2013 and January 2014. The mixed waters reached a much higher net primary production and chlorophyll a (chla) concentration than the original waters already 2–3 days after their merging. The peak in phytoplankton biomass stays longer than the chla peak. After their maxima, primary production rates decreased quickly due to depletion of the nutrients. The increase in colored dissolved organic matter (CDOM) may indicate excretion and degradation. Zooplankton is not quickly reacting on the changed conditions. We conclude that already simple mixing of two water bodies, which occurs generally at fronts between upwelled and ambient water, leads to a short-term stimulation of the phytoplankton growth. However, after the exhaustion of the nutrient stock, external nutrient supply is necessary to maintain the enhanced phytoplankton growth in the frontal area. Based on these data, some generally important ecological factors are discussed as for example nutrient ratios and limitations, silicate requirements and growth rates

    High density of ice krill (Euphausia crystallorophias) in the Amundsen sea coastal polynya, Antarctica

    Get PDF
    High densities of ice krill Euphausia crystallorophias were observed along six acoustic transects within the Amundsen Sea Coastal Polynya, Antarctica. Two-frequency acoustic backscatter data was examined in the austral summers of January 2011 and February 2012. A dB identification window (Sv120−38) identified ice krill dominating the acoustic backscatter. The density of ice krill, calculated with the stochastic distorted-wave born approximation model, ranged between 4.5 and 30 g wet mass m−2 for each transect (a mean of 16 g wet mass m−2 for all transects), these high values are an order of magnitude higher than recorded previously in the Ross Sea Polynya. High densities were detected along the ice shelf and near the boundary between pack ice and coastal polynya, and we postulate that these could be important habitats for ice krill. The high densities observed along the transects make ice krill a potentially important, but poorly known contributor to these high-latitude shelf food webs

    Complete next-to-leading order gluino contributions to b--> s gamma and b--> s g

    Full text link
    We present the first complete order alpha_s corrections to the Wilson coefficients (at the high scale) of the various versions of magnetic and chromomagnetic operators which are induced by a squark-gluino exchange. For this matching calculation, we work out the on-shell amplitudes b--> s gamma and b --> s g, both in the full and in the effective theory up to order alpha_s^2. The most difficult part of the calculation is the evaluation of the two-loop diagrams in the full theory; these can be split into two classes: a) diagrams with one gluino and a virtual gluon; b) diagrams with two gluinos or with one gluino and a four-squark vertex. Accordingly, the Wilson coefficients can be split into a part a) and a part b). While part b) of the Wilson coefficients is presented in this paper for the first time, part a) was given in (Bobeth et al.). We checked their results for the coefficients of the magnetic operators and found perfect agreement. Moreover, we work out the renormalization procedure in great detail. Our results for the complete next-to-leading order Wilson coefficients are fully analytic, but far too long to be printed. We therefore publish them in the form of a C++ program. They constitute a crucial building block for the phenomenological next-to-leading logarithmic analysis of the branching ratio Bbar --> X_s gamma in a supersymmetric model beyond minimal flavor violation.Comment: 38 pages, including c++ cod

    Small Interfering RNA Efficiently Suppresses Adhesion Molecule Expression on Pulmonary Microvascular Endothelium

    Get PDF
    Background. Adhesion molecules are known to influence postoperative organ function, they are hardly involved in the inflammatory response following the ischemia-reperfusion injury. We sought to investigate the potency of small interfering RNAs to suppress adhesion molecule expression in human pulmonary microvascular endothelial cells. Methods. Human lung microvascular endothelial cells were transfected with specific siRNA followed by a stimulation of the cells with an inflammatory cytokine. Adhesion molecule expression was determined by FACS-analysis, and reduction of intracellular mRNA was determined by qRT-PCR. Furthermore, the attachment of isolated neutrophils on the endothelial layer was determined after siRNA transfection. Results. In summary, siRNA transfection significantly decreased the percentage positive cells in a single cocktail transfection of each adhesion molecule investigated. Adhering neutrophils were diminished as well. Conclusion. siRNA might be a promising tool for the effective suppression of adhesion molecule expression on pulmonary microvascular cells, potentially minimizing leukocyte-endothelial depending interactions of a pulmonary allograft

    Branching ratio change in K- absorption at rest and the nature of the Lambda(1405)

    Full text link
    We investigate in-medium corrections to the branching ratio in K- absorption at rest and their effect on the (positively and negatively) charged pion spectrum. The in-medium corrections are due to Pauli blocking, which arises if the Lambda(1405) is assumed to be a Kˉ\bar{K}-nucleon bound state and leads to a density and momentum dependent mass shift of the Lambda(1405). Requiring that the optical potential as well as the branching ratio are derived from the same elementary T-matrix, we find that the in-medium corrected, density dependent T-matrix gives a better description of the K- absorption reaction than the free, density-independent one. This result suggests that the dominant component of the Lambda(1405) wave function is the KˉN\bar{K}N bound state.Comment: 8 Pages, Revtex with epsf, and embedded 8 ps figure

    Hydrographic-hydrochemical assessment of the Baltic Sea 2017

    Get PDF
    ENGLISH ABSTRACT: The article summarizes the hydrographic-hydrochemical conditions in the western and central Baltic Sea in 2017. Based on meteorological conditions, the horizontal and vertical distribution of temperature, salinity, oxygen/hydrogen sulphide and nutrients are described on a seasonal scale. For the southern Baltic Sea area, the “cold sum” of the air temperature of 31.7 Kd in WarnemĂŒnde amounted to a mild winter in 2014/15 and ranks as 15th warmest winter since the beginning of the record in 1948. The summer “heat sum” of 159.5 Kd ranks on 28th position of the warmest summers over the past 70 years and is slightly above the long-term average of 153.4 Kd. Based on satellite derived Sea Surface Temperature (SST) 2017 was the eleventh-warmest year since 1990 and with 0.24 K slightly above the long-term SST average. March, April and October - December contributed to the average by their positive anomalies. July and August were characterized by negative anomalies. The anomalies reached maximum values of +2 K and -3 K. The situation in the deep basins of the Baltic Sea was mainly coined by beginning stagnation at bottom-near water depths of the eastern Gotland Basin and ongoing ventilation of the upper part 5 of the deep-water above 150 m as a consequence of weak inflows. For the first time within this phase of intensified inflow activity, starting in 2014, the ventilation of the Farö Deep at the Northern Central Basin was registered at the beginning of the year. In the course of 2017 two weak inflows showing total volumes of 210 km^Âł (February) and 188 km^Âł (October) were registered. In conclusion, the impact of the observed phase of intensified water exchange processes with subsequent consequences for the biogeochemical cycles is weakening. GERMAN ABSTRACT: Die Arbeit beschreibt die hydrographisch-hydrochemischen Bedingungen in der westlichen und zentralen Ostsee fĂŒr das Jahr 2017. Basierend auf den meteorologischen VerhĂ€ltnissen werden die horizontalen und vertikalen Verteilungsmuster von Temperatur, Salzgehalt, Sauerstoff/ Schwefelwasserstoff und NĂ€hrstoffen mit saisonaler Auflösung dargestellt. FĂŒr den sĂŒdlichen Ostseeraum ergab sich eine KĂ€ltesumme der Lufttemperatur an der Station WarnemĂŒnde von 31,7 Kd. Im Vergleich belegt der Winter 2016/17 den 15. Platz der wĂ€rmsten Winter seit Beginn der Aufzeichnungen im Jahr 1948 und wird als mild klassifiziert. Mit einer WĂ€rmesumme von 159,5 Kd rangiert der Sommer im Mittelfeld der 70jĂ€hrigen Datenreihe und reiht sich auf Platz 28 der wĂ€rmsten Sommer ein. Das Langzeitmittel liegt bei 153,4 Kd. Auf der Grundlage von satellitengestĂŒtzten MeeresoberflĂ€chentemperaturen (SST) war 2017 das elft- wĂ€rmste Jahr seit 1990 und mit 0,24 K etwas ĂŒber dem langfristigen SST-Mittel. MĂ€rz, April und Oktober - Dezember trugen durch ihre positiven Anomalien zum Durchschnitt bei. Juli und August waren durch negative Anomalien gekennzeichnet. Die Anomalien erreichten Höchstwerte von +2 K und -3 K. Die Situation in den Tiefenbecken der Ostsee war im Wesentlichen geprĂ€gt durch bodennah einsetzende Stagnation im östlichen Gotland Becken und BelĂŒftung der mittleren WassersĂ€ule oberhalb 150 m im Zuge kleinerer Einströme. Zu Jahresbeginn wurde das im nördlichen Zentralbecken gelegene Farö Tief erstmals innerhalb der aktuellen Einstromphase belĂŒftet. Im Jahresverlauf 2017 wurden zwei weitere schwache Einströme mit Volumina zwischen 210 kmÂł und 188 kmÂł im Februar sowie Oktober registriert. Zusammenfassend kann gesagt werden, dass die Auswirkungen der seit 2014 beobachten Phase von verstĂ€rkten Wasseraustauschprozessen mit entsprechenden Konsequenzen fĂŒr die biogeochemischen KreislĂ€ufe abklingen

    Preoperative short-course radiotherapy versus combined radiochemotherapy in locally advanced rectal cancer: a multi-centre prospectively randomised study of the Berlin Cancer Society

    Get PDF
    BACKGROUND: The additional use of radiotherapy has changed the treatment of locally advanced rectal cancer (LARC) dramatically. But a major achievement has been the development of total mesorectal excision (TME) as a surgical standard and the recognition that the surgeon is the predominant prognostic factor. The benefit of preoperative hypofractionated radiotherapy (SCRT; five fractions each of 5 Gy), initially established by the Swedish Rectal Cancer Trial, has been demonstrated in conjunction with TME by the Dutch Colorectal Cancer Group. The concept of combined neoadjuvant radiochemotherapy (conventional radiation of about 50 Gy with chemotherapy) has not been compared over surgery alone with TME. However, the German Rectal Cancer Study Group recently demonstrated that preoperative radiochemotherapy (RCT) was better than postoperative radiochemotherapy in terms of local control. METHODS: Patients with histological proven rectal cancer staged T2N+ or T3 are randomized to receive either SCRT (25 Gy in five fractions of 5 Gy) plus TME-surgery within 5 days or RCT (50.4 Gy in 28 fractions of 1.8 Gy, continuous infusion 5-fluorouracil) plus TME-surgery 4-6 weeks later. All patients receive adjuvant chemotherapy (12 weeks continuous infusional 5-FU) and are followed up for 5 years. TME-quality is independently documented by the surgeon and the pathologist. Hypothesis of the study is that RCT is superior to SCRT in terms of local recurrence after five years. Secondary endpoints are overall survival, disease-free survival, complete resection rate (R0 resection), rate of sphincter saving resection, acute and late toxicity (radiation related side effects), and quality of life (including long term bowel function). DISCUSSION: Similar long-term survival, local control and late morbidity have been reported for both concepts of preoperative therapy in non-comparative studies. In addition to other ongoing (and recently published) comparative trials we include a larger number of patients for adequate power, apply quality-controlled TME and try to avoid the adjuvant treatment bias by mandatory adjuvant chemotherapy in both groups. Further more, stratification of the initially planned surgical procedure and sphincter-preservation will generate valid evidence whether RCT will allow a less aggressive (sphincter saving) surgical approach

    The Association of Antarctic Krill Euphausia superba with the Under-Ice Habitat

    Get PDF
    The association of Antarctic krill Euphausia superba with the under-ice habitat was investigated in the Lazarev Sea (Southern Ocean) during austral summer, autumn and winter. Data were obtained using novel Surface and Under Ice Trawls (SUIT), which sampled the 0–2 m surface layer both under sea ice and in open water. Average surface layer densities ranged between 0.8 individuals m−2 in summer and autumn, and 2.7 individuals m−2 in winter. In summer, under-ice densities of Antarctic krill were significantly higher than in open waters. In autumn, the opposite pattern was observed. Under winter sea ice, densities were often low, but repeatedly far exceeded summer and autumn maxima. Statistical models showed that during summer high densities of Antarctic krill in the 0–2 m layer were associated with high ice coverage and shallow mixed layer depths, among other factors. In autumn and winter, density was related to hydrographical parameters. Average under-ice densities from the 0–2 m layer were higher than corresponding values from the 0–200 m layer collected with Rectangular Midwater Trawls (RMT) in summer. In winter, under-ice densities far surpassed maximum 0–200 m densities on several occasions. This indicates that the importance of the ice-water interface layer may be under-estimated by the pelagic nets and sonars commonly used to estimate the population size of Antarctic krill for management purposes, due to their limited ability to sample this habitat. Our results provide evidence for an almost year-round association of Antarctic krill with the under-ice habitat, hundreds of kilometres into the ice-covered area of the Lazarev Sea. Local concentrations of postlarval Antarctic krill under winter sea ice suggest that sea ice biota are important for their winter survival. These findings emphasise the susceptibility of an ecological key species to changing sea ice habitats, suggesting potential ramifications on Antarctic ecosystems induced by climate change
    • 

    corecore