Reaction-diffusion systems: Destabilizing effect of conditions given by inclusions II, Examples

summary:The destabilizing effect of four different types of multivalued conditions describing the influence of semipermeable membranes or of unilateral inner sources to the reaction-diffusion system is investigated. The validity of the assumptions sufficient for the destabilization which were stated in the first part is verified for these cases. Thus the existence of points at which the spatial patterns bifurcate from trivial solutions is proved

Critical points for reaction-diffusion system with one and two unilateral conditions

summary:We show the location of so called critical points, i.e., couples of diffusion coefficients for which a non-trivial solution of a linear reaction-diffusion system of activator-inhibitor type on an interval with Neumann boundary conditions and with additional non-linear unilateral condition at one or two points on the boundary and/or in the interior exists. Simultaneously, we show the profile of such solutions

Do clones degenerate over time? Explaining the genetic variability of asexuals through population genetic models

<p>Abstract</p> <p>Background</p> <p>Quest for understanding the nature of mechanisms governing the life span of clonal organisms lasts for several decades. Phylogenetic evidence for recent origins of most clones is usually interpreted as proof that clones suffer from gradual age-dependent fitness decay (e.g. Muller's ratchet). However, we have shown that a neutral drift can also qualitatively explain the observed distribution of clonal ages. This finding was followed by several attempts to distinguish the effects of neutral and non-neutral processes. Most recently, Neiman et al. 2009 (Ann N Y Acad Sci.:1168:185-200.) reviewed the distribution of asexual lineage ages estimated from a diverse array of taxa and concluded that neutral processes alone may not explain the observed data. Moreover, the authors inferred that similar types of mechanisms determine maximum asexual lineage ages in all asexual taxa. In this paper we review recent methods for distinguishing the effects of neutral and non-neutral processes and point at methodological problems related with them.</p> <p>Results and Discussion</p> <p>We found that contemporary analyses based on phylogenetic data are inadequate to provide any clear-cut answer about the nature and generality of processes affecting evolution of clones. As an alternative approach, we demonstrate that sequence variability in asexual populations is suitable to detect age-dependent selection against clonal lineages. We found that asexual taxa with relatively old clonal lineages are characterised by progressively stronger deviations from neutrality.</p> <p>Conclusions</p> <p>Our results demonstrate that some type of age-dependent selection against clones is generally operational in asexual animals, which cover a wide taxonomic range spanning from flatworms to vertebrates. However, we also found a notable difference between the data distribution predicted by available models of sequence evolution and those observed in empirical data. These findings point at the possibility that processes affecting clonal evolution differ from those described in recent studies, suggesting that theoretical models of asexual populations must evolve to address this problem in detail.</p> <p>Reviewers</p> <p>This article was reviewed by Isa Schön (nominated by John Logsdon), Arcady Mushegian and Timothy G. Barraclough (nominated by Laurence Hurst).</p

Genome fractionation and loss of heterozygosity in hybrids and polyploids: Mechanisms, consequences for selection, and link to gene function

Hybridization and genome duplication have played crucial roles in the evolution of many animal and plant taxa. The subgenomes of parental species undergo considerable changes in hybrids and polyploids, which often selectively eliminate segments of one subgenome. However, the mechanisms underlying these changes are not well understood, particularly when the hybridization is linked with asexual reproduction that opens up unexpected evolutionary pathways. To elucidate this problem, we compared published cytogenetic and RNAseq data with exome sequences of asexual diploid and polyploid hybrids between three fish species; Cobitis elongatoides, C taenia, and C tanaitica. Clonal genomes remained generally static at chromosome-scale levels but their heterozygosity gradually deteriorated at the level of individual genes owing to allelic deletions and conversions. Interestingly, the impact of both processes varies among animals and genomic regions depending on ploidy level and the properties of affected genes. Namely, polyploids were more tolerant to deletions than diploid asexuals where conversions prevailed, and genomic restructuring events accumulated preferentially in genes characterized by high transcription levels and GC-content, strong purifying selection and specific functions like interacting with intracellular membranes. Although hybrids were phenotypically more similar to C taenia, we found that they preferentially retained C elongatoides alleles. This demonstrates that favored subgenome is not necessarily the transcriptionally dominant one. This study demonstrated that subgenomes in asexual hybrids and polyploids evolve under a complex interplay of selection and several molecular mechanisms whose efficiency depends on the organism's ploidy level, as well as functional properties and parental ancestry of the genomic region.Web of Science38125274525

Lack in Periodontal Care of Patients Suffering from Severe Heart Diseases—Results after 12 Months Follow-Up

Background: To assess whether the standardized recommendation of patients with heart failure (HF), left-ventricular assist device (LVAD) and heart transplantation (HTx) to visit their dentist leads to improved oral conditions after 12 months. Methods: Patients from the Department of Cardiothoracic Surgery, Leipzig Heart Centre, Germany were examined at baseline and after 12 months. A dental (decayed-, missing-, and filled-teeth index (DMF-T)) and periodontal examination (periodontal probing depth, clinical attachment loss) was performed. At baseline, patients received a standardized recommendation to visit their dentist. At follow-up, a standardized questionnaire regarding the dental consultation was applied. Results: Eighty-eight participants (HTx: 31, LVAD: 43, HF: 14) were included. The majority of patients (79.5%) followed the recommendation to visit their dentist. Within the total cohort, periodontal treatment need was significantly reduced from 91% (baseline) to 75% (follow-up; p 0.05). Conclusions: The simple recommendation to visit the dentist appears not enough to obtain sufficient dental and periodontal conditions in patients with severe heart diseases. Thereby, a lack in periodontal treatment of patients with HF, HTx and LVAD was identified, making interdisciplinary dental special care programs recommendable

Adjustment of global precipitation data for enhanced hydrologic modeling of tropical Andean watersheds

Global gridded precipitation is an essential driving input for hydrologic models to simulate runoff dynamics in large river basins. However, the data often fail to adequately represent precipitation variability in mountainous regions due to orographic effects and sparse and highly uncertain gauge data. Water balance simulations in tropical montane regions covered by cloud forests are especially challenging because of the additional water input from cloud water interception. The ISI-MIP2 hydrologic model ensemble encountered these problems for Andean sub-basins of the Upper Amazon Basin, where all models significantly underestimated observed runoff. In this paper, we propose simple yet plausible ways to adjust global precipitation data provided by WFDEI, the WATCH Forcing Data methodology applied to ERA-Interim reanalysis, for tropical montane watersheds. The modifications were based on plausible reasoning and freely available tropics-wide data: (i) a high-resolution climatology of the Tropical Rainfall Measuring Mission (TRMM) and (ii) the percentage of tropical montane cloud forest cover. Using the modified precipitation data, runoff predictions significantly improved for all hydrologic models considered. The precipitation adjustment methods presented here have the potential to enhance other global precipitation products for hydrologic model applications in the Upper Amazon Basin as well as in other tropical montane watersheds

Robotische Hernienchirurgie I

The treatment of inguinal hernias with open and minimally invasive procedures has reached a high standard in terms of outcome over the past 30 years. However, there is still need for further improvement, mainly in terms of reduction of postoperative seroma, chronic pain, and recurrence. This video article presents the endoscopic anatomy of the groin with regard to robotic transabdominal preperitoneal patch plasty (r‑TAPP) and illustrates the surgical steps of r‑TAPP with respective video sequences. The results of a cohort study of 302 consecutive hernias operated by r‑TAPP are presented and discussed in light of the added value of the robotic technique, including advantages for surgical training. r‑TAPP is the natural evolution of conventional TAPP and has the potential to become a new standard as equipment availability increases and material costs decrease. Future studies will also have to refine the multifaceted added value of r‑TAPP with new parameters

Influence of spatial resolution on snow cover dynamics for a coastal and mountainous region at high latitudes (Norway)

Climate models show that global warming will disproportionately influence high‐latitude regions and indicate drastic changes in, among others, seasonal snow cover. However, current continental and global simulations covering these regions are often run at coarse grid resolutions, potentially introducing large errors in computed fluxes and states. To quantify some of these errors, we have assessed the sensitivity of an energy‐balance snow model to changes in grid resolution using a multiparametrization framework for the spatial domain of mainland Norway. The framework has allowed us to systematically test how different parametrizations, describing a set of processes, influence the discrepancy, here termed the scale error, between the coarser (5 to 50‐km) and finest (1‐km) resolution. The simulations were set up such that liquid and solid precipitation was identical between the different resolutions, and differences between the simulations arise mainly during the ablation period. The analysis presented in this study focuses on evaluating the scale error for several variables relevant for hydrological and land surface modelling, such as snow water equivalent and turbulent heat exchanges. The analysis reveals that the choice of method for routing liquid water through the snowpack influences the scale error most for snow water equivalent, followed by the type of parametrizations used for computing turbulent heat fluxes and albedo. For turbulent heat exchanges, the scale error is mainly influenced by model assumptions related to atmospheric stability. Finally, regions with strong meteorological and topographic variability show larger scale errors than more homogenous regions.publishedVersio

High-Precision Radio and Infrared Astrometry of LSPM J1314+1320AB - I : Parallax, Proper Motions, and Limits on Planets

Jan Forbrich, et al, 'HIGH-PRECISION RADIO AND INFRARED ASTROMETRY OF LSPM J1314+1320AB. I.PARALLAX, PROPER MOTIONS, AND LIMITS ON PLANETS', The Astrophysical Journal, 827:22 (8pp), August 2016. doi:10.3847/0004-637X/827/1/22. © 2016. The American Astronomical Society. All rights reserved.We present multi-epoch astrometric radio observations with the Very Long Baseline Array (VLBA) of the young ultracool-dwarf binary LSPM J1314+1320AB . The radio emission comes from the secondary star. Combining the VLBA data with Keck near-infrared adaptive-optics observations of both components, a full astrometric fit of parallax ($\pi_{\rm abs}=57.975\pm0.045$ mas, corresponding to a distance of $d=17.249\pm0.013$ pc), proper motion ($\mu_{\rm \alpha cos \delta}=-247.99\pm0.10$ mas yr$^{-1}$, $\mu_{\delta}=-183.58\pm0.22$ mas yr$^{-1}$), and orbital motion is obtained. Despite the fact that the two components have nearly identical masses to within $\pm2$%, the secondary's radio emission exceeds that of the primary by a factor of $\gtrsim$30, suggesting a difference in stellar rotation history, which could result in different magnetic field configurations. Alternatively, the emission could be anisotropic and beamed toward us for the secondary but not for the primary. Using only reflex motion, we exclude planets of mass 0.7 to 10 $M_{\rm jup}$ with orbital periods of 600 to 10 days, respectively. Additionally, we use the full orbital solution of the binary to derive an upper limit for the semi-major axis of 0.23 AU for stable planetary orbits within this system. These limits cover a parameter space that is inaccessible with, and complementary to, near-infrared radial velocity surveys of ultracool dwarfs. Our absolute astrometry will constitute an important test for the astrometric calibration of Gaia.Peer reviewe