Rank-Based Analysis of Linear Models Using R

It is well-known that Wilcoxon procedures out perform least squares procedures when the data deviate from normality and/or contain outliers. These procedures can be generalized by introducing weights; yielding so-called weighted Wilcoxon (WW) techniques. In this paper we demonstrate how WW-estimates can be calculated using an L1 regression routine. More importantly, we present a collection of functions that can be used to implement a robust analysis of a linear model based on WW-estimates. For instance, estimation, tests of linear hypotheses, residual analyses, and diagnostics to detect differences in fits for various weighting schemes are discussed. We analyze a regression model, designed experiment, and autoregressive time series model for the sake of illustration. We have chosen to implement the suite of functions using the R statistical software package. Because R is freely available and runs on multiple platforms, WW-estimation and associated inference is now universally accessible.

Experiments on the formation of carboxylase and thiamine pyrophosphate in living bakers' yeast

The formation of carboxylase by living bakers' yeast was demonstrated upon incubation of the yeast with either thiamine or 2-methyl-4-amino-5-ethoxymethylpyrimidine, in the presence and in the absence of glucose. Carboxylase is also formed upon incubation of the yeast with NH4 sulfate and glucose. In the presence of glucose the effects of thiamine + NH4 sulfate or 2-methyl-4-amino-5-ethoxymethylpyrimidine + NH4 sulfate considerably surpass the effects of any of these substances separately. The effect of 2-methyl-4-amino-5-ethoxymethylpyrimidine depends upon the primary formation of thiamine pyrophosphate

Rank-Based Analysis of Linear Models Using R

It is well-known that Wilcoxon procedures out perform least squares procedures when the data deviate from normality and/or contain outliers. These procedures can be generalized by introducing weights; yielding so-called weighted Wilcoxon (WW) techniques. In this paper we demonstrate how WW-estimates can be calculated using an L1 regression routine. More importantly, we present a collection of functions that can be used to implement a robust analysis of a linear model based on WW-estimates. For instance, estimation, tests of linear hypotheses, residual analyses, and diagnostics to detect differences in fits for various weighting schemes are discussed. We analyze a regression model, designed experiment, and autoregressive time series model for the sake of illustration. We have chosen to implement the suite of functions using the R statistical software package. Because R is freely available and runs on multiple platforms, WW-estimation and associated inference is now universally accessible

BubbleStorm: Rendezvous Theory in Unstructured Peer-to-Peer Search

This thesis presents BubbleStorm, which attempts to bridge the gap between peer-to-peer and databases. BubbleStorm is a peer-to-peer search system, which solves large-scale rendezvous problems over the unreliable global internet. It provides a concept of user-defined bubble types, loosely corresponding to table schemas. Queries follow the fully general black-box model, allowing powerful queries to be evaluated exhaustively. The system tracks usage statistics with a system-wide measurement service, used to automatically tune search performance. As strong consistency guarantees are impossible, BubbleStorm instead aims for user-controlled probabilistic guarantees. The key contribution of this thesis is to develop rendezvous theory and reformulate the black-box query model within this framework. This reformulation allows us to interpret any black-box system as solving a rendezvous problem, allowing an elegant and tight lower-bound. BubbleStorm leverages rendezvous theory to substantially reduce bandwidth consumption (both practically and asymptotically) while simultaneously improving query latency. The resulting system, which has a full fledged implementation, sports a simple to understand interface, which abstracts away the underlying details, much like the database systems before it

A Peer-to-Peer Approach to Content-Based Publish/Subscribe

Publish/subscribe systems are successfully used to decouple distributed applications. However, their e#ciency is closely tied to the topology of the underlying network, the design of which has been neglected. Peer-to-peer network topologies can o#er inherently bounded delivery depth, load sharing, and self-organisation. In this paper, we present a contentbased publish/subscribe system routed over a peer-to-peer topology graph. The implications of combining these approaches are explored and a particular implementation using elements from Rebeca and Chord is proven correct

Metabolism of Poly(3-hydroxyalkanoates) (PHAs) by Pseudomonas oleovorans. Identification and Sequences of Genes and Function of the Encoded Proteins in the Synthesis and Degradation of PHA

Pseudomonas oleovorans accumulates poly(3-hydroxyalkanoates) (PHAs) after growth on medium chain length hydrocarbons. Large amounts of this polyester are synthesized when cells are grown under nitrogen-limiting conditions. When nitrogen is resupplied in the medium, the accumulated PHA is degraded. In this paper, we describe mutants which are defective in the synthesis or in the degradation of PHA. These mutants were used to select DNA fragments which encode PHA polymerases and a PHA depolymerase. A 25-kilobase (kb) DNA fragment was isolated from P. oleovorans that complements a Pseudomonas putida mutant unable to accumulate PHA. Subcloning resulted in the assignment of a 6.4-kb EcoRI fragment as the pha locus, containing genetic information of PHA synthesis. Mutants in the PHA degradation pathway were also complemented by this fragment, indicating that genes encoding PHA biosynthetic and degradative enzymes are clustered. Analysis of the DNA sequence of the 6.4-kb fragment revealed the presence of two open reading frames encoding PHA polymerases based on homology to the poly(3-hydroxybutyrate) polymerase from Alcaligenes eutrophus. A third open reading frame complemented the PHA degradation mutation and is likely to encode a PHA depolymerase. The presence of two PHA polymerases is due to a 2098-base pair DNA duplication. The PHA polymerases are 53% identical and show 35-40% identity to the poly(3-hydroxybutyrate) polymerase. No clear difference in specificity was found for the PHA polymerases. However, with the pha locus cloned on a multicopy vector, a polymer was accumulated that contains a significantly higher amount of substrate-derived monomers. An increase in the rate of polyester synthesis versus oxidation of the monomers in the beta-oxidation explains these findings

Специфіка формування іміджу українських телеканалів

Статья посвящена анализу имиджевых характеристик ведущих украинских телевизионных канатов - Первого национального, «1+1», «Интера», СТБ, ICTV. Мы проанализировали имиджевые характеристики всех каналов и обобщили тенденции дальнейшего формирования имиджа украинских телеканалов.Статтю присвячено аналізу іміджевих характеристик провідних українських телевізійних каналів - Першого національного, «1+1», «Інтеру», СТБ, ICTV. Проаналізовано іміджеві риси кожного з каналів та узагальнено тенденції щодо подальшого формування іміджу українських телеканалів.Article is dedicated the analysis an image particularity of leading Ukrainian television channels - First national, " 1+1 " , "Inter", STB, ІСТV. We have analysed the image particularity of all channels and have generalised the trends of the further creation image Ukrainian telechannels

Facilitated engraftment of human hematopoietic cells in severe combined immunodeficient mice following a single injection of Cl²MDP liposomes

Transplantation of normal and malignant human hematopoietic cells into severe combined immunodeficient (SCID) mice allows for evaluation of long-term growth abilities of these cells and provides a preclinical model for therapeutic interventions. However, large numbers of cells are required for successful engraftment in preirradiated mice due to residual graft resistance, that may be mediated by cells from the mononuclear phagocytic system. Intravenous (i.v.) injection of liposomes containing dichloromethylene diphosphonate (Cl2MDP) may eliminate mouse macrophages in spleen and liver. In this study outgrowth of acute myeloid leukemia (AML) cells and umbilical cord blood (UCB) cells in SCID mice conditioned with a single i.v. injection of Cl2MDP liposomes in addition to sublethal total body irradiation (TBI) was compared to outgrowth of these cells in SCID mice that had received TBI alone. A two- to 10-fold increase in outgrowth of AML cells was observed in four cases of AML. Administration of 107 UCB cells reproducibly engrafted SCID mice that had been conditioned with Cl2MDP liposomes and TBI, whereas human cells were not detected in mice conditioned with TBI alone. As few as 2 x 104 purified CD34+ UCB cells engrafted in all mice treated with Cl2MDP liposomes. In SCID mice treated with macrophage depletion unexpected graft failures were not observed. Histological examination of the spleen showed that TBI and Cl2MDP liposomes i.v. resulted in a transient elimination of all macrophage subsets in the spleen, whereas TBI had a minor effect. Cl2MDP liposomes were easy to use and their application was not associated with appreciable side-effects. Cl2MDP liposome pretreatment in combination with TBI allows for reproducible outgrowth of high numbers of human hematopoietic cells in SCID mice