102 research outputs found

    Using Virtual Observatory techniques to search for Adaptive Optics suitable AGN

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    Until recently, it has been possible only for nearby galaxies to study the scaling relations between central black hole and host galaxy in detail. Because of the small number densities at low redshift, (luminous) AGN are underrepresented in such detailed studies. The advent of adaptive optics (AO) at large telescopes helps overcoming this hurdle, allowing to reach small linear scales over a wide range in redshift. Finding AO-suitable targets, i.e., AGN having a nearby reference star, and carrying out an initial multiwavelength classification is an excellent use case for the Virtual Observatory. We present our Virtual-Observatory approach to select an AO-suitable catalog of X-ray-emitting AGN at redshifts 0.1<z<1.Comment: 4 pages, 5 figures, submitted to "EURO-VO AIDA workshop: Multiwavelength astronomy and Virtual Observatory", ESAC, Spain, 1-3 Dec. 200

    Mass Die-Off of Saiga Antelopes, Kazakhstan, 2015

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    In 2015, a mass die-off of ā‰ˆ200,000 saiga antelope in central Kazakhstan was caused by hemorrhagic septicemia attributable to the bacterium Pasteurella multocida serotype B. Previous analyses have indicated that environmental triggers associated with weather conditions, specifically air moisture and temperature in the region of the saiga antelope calving during the 10-day period running up to the event, were critical to the proliferation of latent bacteria and were comparable to conditions accompanying historically similar die-offs in the same areas. We investigated whether additional viral or bacterial pathogens could be detected in samples from affected animals using 3 different high-throughput sequencing approaches. We did not identify pathogens associated with commensal bacterial opportunisms in blood, kidney, or lung samples and thus concluded that P. multocida serotype B was the primary cause of the disease

    Dissecting Rice Polyamine Metabolism under Controlled Long-Term Drought Stress

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    A selection of 21 rice cultivars (Oryza sativa L. ssp. indica and japonica) was characterized under moderate long-term drought stress by comprehensive physiological analyses and determination of the contents of polyamines and selected metabolites directly related to polyamine metabolism. To investigate the potential regulation of polyamine biosynthesis at the transcriptional level, the expression of 21 genes encoding enzymes involved in these pathways were analyzed by qRT-PCR. Analysis of the genomic loci revealed that 11 of these genes were located in drought-related QTL regions, in agreement with a proposed role of polyamine metabolism in rice drought tolerance. The cultivars differed widely in their drought tolerance and parameters such as biomass and photosynthetic quantum yield were significantly affected by drought treatment. Under optimal irrigation free putrescine was the predominant polyamine followed by free spermidine and spermine. When exposed to drought putrescine levels decreased markedly and spermine became predominant in all cultivars. There were no correlations between polyamine contents and drought tolerance. GC-MS analysis revealed drought-induced changes of the levels of ornithine/arginine (substrate), substrates of polyamine synthesis, proline, product of a competing pathway and GABA, a potential degradation product. Gene expression analysis indicated that ADC-dependent polyamine biosynthesis responded much more strongly to drought than the ODC-dependent pathway. Nevertheless the fold change in transcript abundance of ODC1 under drought stress was linearly correlated with the drought tolerance of the cultivars. Combining metabolite and gene expression data, we propose a model of the coordinate adjustment of polyamine biosynthesis for the accumulation of spermine under drought conditions

    Feeding versus Feedback in NGC 4151 probed with Gemini NIFS. I. Excitation

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    We have used the Gemini Near-infrared Integral Field Spectrograph (NIFS) to map the emission-line intensity distributions and ratios in the Narrow-Line Region (NLR) of the Seyfert galaxy NGC 4151 in the Z, J, H and K bands at a resolving power ~ 5000, covering the inner 200 pc x 300 pc of the galaxy at a spatial resolution of 8 pc. We present intensity distributions I(r) in 14 emission lines. (1) For the ionized gas, I(r) is extended to ~ 100 pc from the nucleus along pos. angle PA=60/240 deg-- NE--SW), consistent with an origin in the known biconical outflow; while for the recombination lines I(r) ~ r^-1, for the forbidden lines I(r) is flat (r^0). (2) The H_2 emission lines intensity distributions avoid the region of the bicone, extending to r ~ 60 pc, perpendicular to the bicone axis, supporting an origin for the H_2-emitting gas in the galaxy plane. (3) The coronal lines show a steep intensity profile, described by r^-2. Using the line-ratio maps [Fe II]1.644/1.257 and Pa_b/Br_g we obtain a reddening of E(B-V)~0.5 along the NLR and E(B-V)>1 at the nucleus. Our line-ratio map [Fe II] 1.257/[P II] 1.189 is the first such map of an extragalactic source. Together with the [Fe II]/Pa_b map, these line ratios correlate with the radio intensity distribution, mapping the effects of shocks produced by the radio jet, which probably release the Fe locked in grains and produce the enhancement of the [Fe II] emission observed at ~ 1 arcsec from the nucleus. At these regions, we obtain densities N_e ~4000 cm^-3 and temperatures T_e ~ 15000K for the [Fe II]-emitting gas. For the H_2-emitting gas we obtain T ~ 2100K. The distinct intensity distributions, physical properties and locations of the ionized and molecular gas suggest that the H_2-emitting gas traces the AGN feeding, while the ionized gas traces its feedback.Comment: 22 pages. 14 figures, accepted for publication in MNRA

    Aerobic Exercise during Pregnancy and Presence of Fetal-Maternal Heart Rate Synchronization

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    It has been shown that short-term direct interaction between maternal and fetal heart rates may take place and that this interaction is affected by the rate of maternal respiration. The aim of this study was to determine the effect of maternal aerobic exercise during pregnancy on the occurrence of fetal-maternal heart rate synchronization.In 40 pregnant women at the 36th week of gestation, 21 of whom exercised regularly, we acquired 18 min. RR interval time series obtained simultaneously in the mothers and their fetuses from magnetocardiographic recordings. The time series of the two groups were examined with respect to their heart rate variability, the maternal respiratory rate and the presence of synchronization epochs as determined on the basis of synchrograms. Surrogate data were used to assess whether the occurrence of synchronization was due to chance.In the original data, we found synchronization occurred less often in pregnancies in which the mothers had exercised regularly. These subjects also displayed higher combined fetal-maternal heart rate variability and lower maternal respiratory rates. Analysis of the surrogate data showed shorter epochs of synchronization and a lack of the phase coordination found between maternal and fetal beat timing in the original data.The results suggest that fetal-maternal heart rate coupling is present but generally weak. Maternal exercise has a damping effect on its occurrence, most likely due to an increase in beat-to-beat differences, higher vagal tone and slower breathing rates

    Down-regulation of the myo-inositol oxygenase gene family has no effect on cell wall composition in Arabidopsis

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    The enzyme myo-inositol oxygenase (MIOX; E.C. 1.13.99.1) catalyzes the ring-opening four-electron oxidation of myo-inositol into glucuronic acid, which is subsequently activated to UDP-glucuronic acid (UDP-GlcA) and serves as a precursor for plant cell wall polysaccharides. Starting from single T-DNA insertion lines in different MIOX-genes a quadruple knockdown (miox1/2/4/5-mutant) was obtained by crossing, which exhibits greater than 90% down-regulation of all four functional MIOX genes. Miox1/2/4/5-mutant shows no visible phenotype and produces viable pollen. The alternative pathway to UDP-glucuronic acid via UDP-glucose is upregulated in the miox1/2/4/5-mutant as a compensatory mechanism. Miox1/2/4/5-mutant is impaired in the utilization of myo-inositol for seedling growth. The incorporation of myo-inositol derived sugars into cell walls is strongly (>90%) inhibited. Instead, myo-inositol and metabolites produced from myo-inositol such as galactinol accumulate in the miox1/2/4/5-mutant. The increase in galactinol and raffinose family oligosaccharides does not enhance stress tolerance. The ascorbic acid levels are the same in mutant and wild type plants

    Development of a Model System to Identify Differences in Spring and Winter Oat

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    Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding

    Systematic review: conservative treatments for secondary lymphedema

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    <p>Abstract</p> <p>Background</p> <p>Several conservative (i.e., nonpharmacologic, nonsurgical) treatments exist for secondary lymphedema. The optimal treatment is unknown. We examined the effectiveness of conservative treatments for secondary lymphedema, as well as harms related to these treatments.</p> <p>Methods</p> <p>We searched MEDLINE<sup>Ā®</sup>, EMBASE<sup>Ā®</sup>, Cochrane Central Register of Controlled Trials<sup>Ā®</sup>, AMED, and CINAHL from 1990 to January 19, 2010. We obtained English- and non-English-language randomized controlled trials or observational studies (with comparison groups) that reported primary effectiveness data on conservative treatments for secondary lymphedema. For English-language studies, we extracted data in tabular form and summarized the tables descriptively. For non-English-language studies, we summarized the results descriptively and discussed similarities with the English-language studies.</p> <p>Results</p> <p>Thirty-six English-language and eight non-English-language studies were included in the review. Most of these studies involved upper-limb lymphedema secondary to breast cancer. Despite lymphedema's chronicity, lengths of follow-up in most studies were under 6 months. Many trial reports contained inadequate descriptions of randomization, blinding, and methods to assess harms. Most observational studies did not control for confounding. Many studies showed that active treatments reduced the size of lymphatic limbs, although extensive between-study heterogeneity in areas such as treatment comparisons and protocols, and outcome measures, prevented us from assessing whether any one treatment was superior. This heterogeneity also precluded us from statistically pooling results. Harms were rare (< 1% incidence) and mostly minor (e.g., headache, arm pain).</p> <p>Conclusions</p> <p>The literature contains no evidence to suggest the most effective treatment for secondary lymphedema. Harms are few and unlikely to cause major clinical problems.</p

    Fructan and its relationship to abiotic stress tolerance in plants

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    Numerous studies have been published that attempted to correlate fructan concentrations with freezing and drought tolerance. Studies investigating the effect of fructan on liposomes indicated that a direct interaction between membranes and fructan was possible. This new area of research began to move fructan and its association with stress beyond mere correlation by confirming that fructan has the capacity to stabilize membranes during drying by inserting at least part of the polysaccharide into the lipid headgroup region of the membrane. This helps prevent leakage when water is removed from the system either during freezing or drought. When plants were transformed with the ability to synthesize fructan, a concomitant increase in drought and/or freezing tolerance was confirmed. These experiments indicate that besides an indirect effect of supplying tissues with hexose sugars, fructan has a direct protective effect that can be demonstrated by both model systems and genetic transformation
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