Experience with collaborating managers: node group manager and provisioning manager

This paper presents an autonomic system in which two managers with different responsibilities collaborate to achieve an overall objective within a cluster of server computers. The first, a node group manager, uses modeling and optimization algorithms to allocate server processes and individual requests among a set of server machines grouped into node groups, and also estimates its ability to fulfill its service-level objectives as a function of the number of server machines available in each node group. The second, a provisioning manager, consumes these estimates from one or more node group managers, and uses them to allocate machines to node groups over a longer timescale. We describe the operation of both managers and the information that flows between them, and present the results of some experiments demonstrating the effectiveness of our technique. Furthermore, we relate our architecture to a general autonomic computing architecture based on self-managing resources and patterns of inter-resource collaboration, and to emerging standards in the area of distributed manageability. We also discuss some of the issues involved in incorporating our implementation into existing products in the short term, and describe a number of further directions for this research.     

Identification of 4'-sulphonyloxy-N-(glutathion-S-methylene)-4-aminoazobenzene, a compound conjugated with both sulphate and glutathione, which is a major biliary metabolite of N,N-dimethyl-4-aminoazobenzene

A major biliary metabolite in the rat of the hepatocarcinogen N,N-dimethyl-4-aminoazobenzene (DAB) has been identified as 4′-sulphonyloxy-N-(glutathion-S-methylene)-4-aminoazobenzene. This conjugate can be synthesized by the condensation of 4′-sulphonyloxy-4-aminoazobenzene with formaldehyde and glutathione (GSH).     

Significant hepatic expression of IL-2 and IL-8 in biliary atresia compared with other neonatal cholestatic disorders

ObjectivesAlthough the exact etiology of biliary atresia (BA) is still elusive, inflammation plays a key role. Release of proinflammatory cytokines from activated immune cells perpetuates the injury and causes biliary destruction. We aimed to study interleukin (IL)-2 and IL-8 expression in liver tissue of BA patients compared with other neonatal cholestatic disorders.MethodsThe study included 59 infants with neonatal cholestasis in two groups; BA group (n = 31) and non-BA group (n = 28) with cholestatic disorders other than BA as controls. Demographic, clinical, laboratory, and histopathological parameters were collected. IL-2 and IL-8 immunostaining was performed. Immunostaining in portal cellular infiltrate was scored as positive or negative and expressed as the mean cell count in three portal tracts.ResultsThe mean value of IL-2 and IL-8 positive inflammatory cells was significantly higher in BA than in non-BA group (P-values of 0.004 and 0.002 respectively). IL-2 correlated significantly with IL-8 immunostaining in both BA and non-BA group (P < 0.0001 for both). Furthermore, both cytokines in both groups correlated significantly with inflammatory activity in liver biopsy while there was no significant correlation with the other studied parameters. Yet, there was a trend of increased expression of IL-2 and IL-8 with increasing stage of fibrosis in BA group. This trend was not observed in non-BA group.ConclusionThe significantly higher expression of IL-2 and IL-8 in patients with BA compared to non-BA suggests a potential role for these cytokines in the pathogenesis in therapy of this devastating neonatal hepatic disorder.     

Behavioral stereotypy and some ecological consequences of entrance-shaft placement of the domichnium Sanctum laurentiensis in Ordovician trepostomate Bryozoa

Abstract

The ichnofossil Sanctum laurentiensis from the Late Ordovician (Cincinnatian) of Laurentia is a domichnium tunneled into live colonies of ramose and frondose trepostome Bryozoa. A preferred entrance location was chosen by the trace-making endoskeletozoan. The organism chose to tunnel in positions near growing tips of branches where one of two conditions prevailed. At stereotypical sites, here considered “determinate”, domicile entrances were made where a trepostome branch was in the growth process of bifurcation; sites considered “indeterminate” were chosen where one blade or branch was impinging on another, or on some other nearby substrate, thus interfering with normal colony growth in a random, or non-ontogenetic, manner. This stereotypy is a rare example of demonstrable entrance-siting behavior by an unknown invertebrate organism. A skeleto-structural condition was present at both determinate and indeterminate locations on ramose trepostome colonies. Stereotypical entrance-site choices included a location where bryozoan freewall membrane was compromised or thinned and exozone was incompletely developed. Sanctum producers preferred incomplete exozone in order to access the endozone for excavation to form a domichnium. Middle and Late Ordovician diversification of ramose bryozoan forms stimulated escalation of bioeroder and symbiont taxa in living zoaria thus encouraging further trepostome evolution.     

Two decades of aortic coarctation treatment in children; evaluating techniques

ObjectiveThis study focuses on the evolution of treatment techniques for aortic coarctation in children and assesses long-term morbidity.MethodsThis retrospective cohort study evaluates patients treated for native aortic coarctation, with at least 7 years of follow-up. To assess time-related changes, three time periods were distinguished according to year of primary intervention (era 1, 2 and 3). Operative and long-term follow-up data were collected by patient record reviews.ResultsThe study population consisted of 206 patients (177 surgical and 29 catheter-based interventions), with a median follow-up of 151 months. Anterior approach with simultaneous repair of aortic arch and associated cardiac lesions was more common in the most recent era. Median age at intervention did not change over time. Reintervention was necessary in one third of the cohort with an event-free survival of 74% at 5‑year and 68% at 10-year follow-up. Reintervention rates were significantly higher after catheter-based interventions compared with surgical interventions (hazard ratio [HR] 1.8, 95% confidence interval [CI] 1.04–3.00, p = 0.04) and in patients treated before 3 months of age (HR 2.1, 95% CI 1.27–3.55, p = 0.003). Hypertension was present in one out of five patients.ConclusionNowadays, complex patients with associated cardiac defects and arch hypoplasia are being treated surgically on bypass, whereas catheter-based intervention is introduced for non-complex patients. Reintervention is common and more frequent after catheter-based intervention and in surgery under 3 months of age. One fifth of the 206 patients remained hypertensive.     

The effect of soil tillage and fertilizer use on pearl millet yields in Niger

Farmers in Niger generally do not plow their fields and are therefore unable to incorporate phosphate. Experiments were conducted in Niger to assess the effect of soil tillage, P source, and fertilizer placement on yields of pearl millet (Pennisetum glaucum [L.] R. Br.). Treatments included single superphosphate (SSP) or ground Tahoua phosphate rock (PRT) incorporated into the soil during tillage or SSP surface applied after tillage. In plots which were not tilled, P sources (SSP, PRT, and PAPR-partially acidulated rock) were broadcast on the soil surface with no incorporation. In order to improve P efficiency under zero tillage, P was point placed in the soil near the plant with either broadcast or point-placed urea. Treatments in which tillage was used showed a slight though nonsignificant yield increase over untilled plots. The yield increase did not appear to be due to phosphate incorporation but rather to direct tillage effects on early plant growth. In a comparison of SSP with PRT or PAPR broadcast on soils not receiving tillage, PRT performed poorly relative to the other P sources. SSP outyielded PAPR and PRT in 1986, but in subsequent years, no significant difference was found between PAPR and SSP. Point placement of P or N near the plant did not significantly increase yields over broadcast treatments even though the millet was planted with wide 1×1 m spacing.     

Cohort and tag-site-specific tag-loss rates in mark–recapture studies: A southern elephant seal cautionary case

Marker-loss is a common feature of mark–recapture studies and important as it may bias parameter estimation. A slight alteration in tag-site of double tagged southern elephant seals (Mirounga leonina), marked at Marion Island from 1983 to 2005 in an ongoing mark–recapture program, had important consequences for tag-loss. We calculated age-specific tag-retention rates and cumulative tag-retention probabilities using a maximum likelihood model selection approach in the software application TAG_LOSS 3.2.0. Under the tag-loss independence assumption, double tag-loss of inner interdigital webbing tags (IIT; 17 cohorts) remained below 1% in the first 5 yr and increased monotonically as seals aged, with higher tag-loss in males. Lifetime cumulative IIT tag-loss was 11.9% for females and 18.4% for males, and equivalent for all cohorts. Changing the tag-site to the outer interdigital webbing (OIT; 6 cohorts) resulted in increased and cohort-dependent tag-loss, although the variation (mean ± 95% CI) in cumulative tag-loss probabilities never exceeded 5.3% between cohorts at similar age. Although different studies may homogenize techniques, we advocate the importance of data set-specific assessment of tag-loss rates to ensure greatest confidence in population parameters obtained from mark–recapture experiments. Permanent marking should be implemented where feasible.     

SCRAPP: A tool to assess the diversity of microbial samples from phylogenetic placements

Microbial ecology research is currently driven by the continuously decreasing cost of DNA sequencing and the improving accuracy of data analysis methods. One such analysis method is phylogenetic placement, which establishes the phylogenetic identity of the anonymous environmental sequences in a sample by means of a given phylogenetic reference tree. However, assessing the diversity of a sample remains challenging, as traditional methods do not scale well with the increasing data volumes and/or do not leverage the phylogenetic placement information. Here, we present scrapp , a highly parallel and scalable tool that uses a molecular species delimitation algorithm to quantify the diversity distribution over the reference phylogeny for a given phylogenetic placement of the sample. scrapp employs a novel approach to cluster phylogenetic placements, called placement space clustering, to efficiently perform dimensionality reduction, so as to scale on large data volumes. Furthermore, it uses the phylogeny‐aware molecular species delimitation method mPTP to quantify diversity. We evaluated scrapp using both, simulated and empirical data sets. We use simulated data to verify our approach. Tests on an empirical data set show that scrapp ‐derived metrics can classify samples by their diversity‐correlated features equally well or better than existing, commonly used approaches. scrapp is available at https://github.com/pbdas/scrapp .