Mutual dependencies : ‘change’ and ‘discourse’

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Ultrastructural analysis of chromatin in meiosis I plus II of rye (Secale cereale L.)

Scanning electron microscopy (SEM) proves to be an appropriate technique for imaging chromatin organization in meiosis I and II of rye (Secale cereale) down to a resolution of a few nanometers. It could be shown for the first time that organization of basic structural elements (coiled and parallel fibers, chromomeres) changes dramatically during the progression to metaphase I and II. Controlled loosening with proteinase K (after fixation with glutaraldehyde) provides an enhanced insight into chromosome architecture even of highly condensed stages of meiosis. By selective staining with platinum blue, DNA content and distribution can be visualized within compact chromosomes as well as in a complex arrangement of fibers. Chromatin interconnecting threads, which are typically observed in prophase I between homologous and non-homologous chromosomes, stain clearly for DNA. In zygotene transversion of chromatid strands to their homologous counterparts becomes evident. In pachytene segments of synapsed and non-synapsed homologs alternate. At synapsed regions pairing is so intimate that homologous chromosomes form one filament of structural entity. Chiasmata are characterized by chromatid strands which traverse from one homolog to its counterpart. Bivalents are characteristically fused at their telomeric regions. In metaphase I and II there is no structural evidence for primary and secondary constrictions. Copyright (C) 2003 S. Karger AG, Basel

Parceria Embrapa - Forschungszentrum Jülich (IBG-2) programa Labex Europa/Alemanha, em novos métodos não-invasivos aplicados a fenotipagem de plantas.

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Risk assessment and mapping of extreme floods in non-dyked communities along the Elbe and Mulde Rivers

International audienceAssessing and mapping damage risk of floods for large river basins is still in its infancy. Damage risk is understood to be the combination of flood hazard and the vulnerability of communities to a flood of a particular return period. Risk is calculated and mapped for two communities in which dykes are not located for flood protection: Meissen on the Elbe River and Döbeln in the Mulde catchment. Different methodologies for the computation of flood depth and inundation extent of varying flood return periods (hazard) are compared. Exposure and relative damage to the flooding (vulnerability) based on land-use coverages of different scale are also compared and discussed. A property asset coverage completes the data requirements for the construction of the risk maps. Recommendations for continued research on risk assessments of large river basins conclude the study

Cultivation and analysis of anthocyanin containing types of potatoes in organic farming regarding cultivability and additional health benefits

In a two year research project a representative spectrum of blue potato varieties were cultivated and tested in detail regarding disease infestation, yield potential and the influence of production systems (organic). Cultivation recommendations for blue potatoes could be deduced from this. Furthermore the varying anthocyanin content as well as the antioxidant capacity of the varieties used was analysed. Varieties with a particularly high content will undergo further tests to show the influence of the manner of preparation (boiling, steaming, frying) and determine their use for the processing industry. The combination of ecologically produced potatoes with „additional health benefits“ arouses the customers interest. The cultivation of high yield blue types can be an alternative to the cultivation of yellow fleshed high yield varieties in organic operating companies

Lifetimes and Sizes from Two-Particle Correlation Functions

We discuss the Yano-Koonin-Podgoretskii (YKP) parametrization of the two-particle correlation function for azimuthally symmetric expanding sources. We derive model-independent expressions for the YKP fit parameters and discuss their physical interpretation. We use them to evaluate the YKP fit parameters and their momentum dependence for a simple model for the emission function and propose new strategies for extracting the source lifetime. Longitudinal expansion of the source can be seen directly in the rapidity dependence of the Yano-Koonin velocity.Comment: 15 pages REVTEX, 2 figures included, submitted to Phys. Lett. B, Expanded discussion of disadvantages of standard HBT fit and of Fig.

Merger of black hole-neutron star binaries in full general relativity

We present our latest results for simulation for merger of black hole (BH)-neutron star (NS) binaries in full general relativity which is performed preparing a quasicircular state as initial condition. The BH is modeled by a moving puncture with no spin and the NS by the $\Gamma$-law equation of state with $\Gamma=2$ and corotating velocity field as a first step. The mass of the BH is chosen to be $\approx 3.2 M_{\odot}$ or $4.0M_{\odot}$, and the rest-mass of the NS $\approx 1.4 M_{\odot}$ with relatively large radius of the NS $\approx 13$--14 km. The NS is tidally disrupted near the innermost stable orbit but $\sim 80$--90% of the material is swallowed into the BH and resulting disk mass is not very large as $\sim 0.3M_{\odot}$ even for small BH mass $\sim 3.2M_{\odot}$. The result indicates that the system of a BH and a massive disk of $\sim M_{\odot}$ is not formed from nonspinning BH-NS binaries irrespective of BH mass, although a disk of mass $\sim 0.1M_{\odot}$ is a possible outcome for this relatively small BH mass range as $\sim 3$--4$M_{\odot}$. Our results indicate that the merger of low-mass BH and NS may form a central engine of short-gamma-ray bursts.Comment: 14 pages. To appear in a special issue of Classical and Quantum Gravity: New Frontiers in Numerical Relativit

Quality of life as subjective experience: Reframing of perception in patients with colon cancer undergoing radical resection with or without adjuvant chemotherapy

Purpose and background: We examined whether patients with colon cancer undergoing surgery with or without adjuvant chemotherapy change the internal standards on which they base their quality-of-life (QL) estimation, and, if they do so, whether this reframing alters interpretation of QL findings. These questions were addressed within a randomized clinical trial of the Swiss Group for Clinical Cancer Research (SAKK 40/93). Patients and methods: After radical resection of adenocar-cinoma of the colon (pT1-4pN>0M0 and pT3-4pN0M0) and perioperative chemotherapy, patients were randomized to three treatment arms: observation only (A), 5-FU 450 rag/m2plus Levamisol (B), or 5-FU 600 mg/m2 (C). QL was measured by linear analogue self-assessment indicators. Patients estimated their pre-surgery QL both before surgery and retrospectively thereafter, and their pre-adjuvant QL both at the beginning of randomly assigned chemotherapy or observation and retrospectively about two months later. Thereafter, current QL was assessed. Paired t-tests were used to test the hypotheses of no change. Results: Overall, 187 patients with at least one pair of corresponding questionnaires were analyzed. Patients estimated their pre-surgery QL after surgery significantly lower than before and their pre-adjuvant QL under treatment or observation also lower than at the beginning. In the adjuvant phase, in contradiction to our hypothesis, chemotherapy had almost no impact on these changes attributed to reframing. Conventionally assessed changes indicated an improvement in QL. Patients with treatment C reported less improvement in functional performance than those with B or those under observation (P = 0.04). Patients with treatment B indicated a greater worsening in nausea/vomiting than those with C, whereas patients with observation only showed an improvement (P = 0.0009). After adjustment of current QL scores under treatment or observation to patients' retrospective estimation, the treatment effects were diluted but the overall improvement was substantially amplified in most QL indicators. Conclusions: Patients with colon cancer substantially re-frame their perception in estimating QL both under radical resection and under adjuvant chemotherapy or observation. This effect is an integral part of patients' adaptation to disease and treatment. An understanding of this phenomenon is of particular relevance for patient care. Its role in evaluating QL endpoints in clinical trials needs further investigatio