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Search Results: 1 - 10 of 65 matches for " Cogan "
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Lattice Operators and Topologies
Eva Cogan
International Journal of Mathematics and Mathematical Sciences , 2009, DOI: 10.1155/2009/474356
Abstract: Working within a complete (not necessarily atomic) Boolean algebra, we use a sublattice to define a topology on that algebra. Our operators generalize complement on a lattice which in turn abstracts the set theoretic operator. Less restricted than those of Banaschewski and Samuel, the operators exhibit some surprising behaviors. We consider properties of such lattices and their interrelations. Many of these properties are abstractions and generalizations of topological spaces. The approach is similar to that of Bachman and Cohen. It is in the spirit of Alexandroff, Frolík, and Nöbeling, although the setting is more general. Proceeding in this manner, we can handle diverse topological theorems systematically before specializing to get as corollaries as the topological results of Alexandroff, Alo and Shapiro, Dykes, Frolík, and Ramsay.
Um modelo de reconcilia??o de dados para o custeio baseado-em-atividades (ABC)
Cogan, Samuel;
Revista de Administra??o de Empresas , 1999, DOI: 10.1590/S0034-75901999000200006
Abstract: cost structure changes, due to new production technologies, to major diversification needed because of business competitivity, and to cost reduction, have motivated the development programmes of new cost management techniques that allocate indirect costs to each product more precisely. in this context, activity-based costing/activity- based management (abc/abm) is considered as one of the most important techniques that have emerged in the last few years to provide accurate estimates for indirect expenses that each product consumes. nevertheless, some difficulties to obtain some costs remain, even when using abc. this happens not only due to the impossibility to measure costs with adequate accuracy, but also due to the fact that the investments made to measure some costs exceed the benefits to be obtained. in order to address this problem, the present work provides a business cost flow framework utilizing data reconciliation used in chemical process networks to determine indirect costs, incorporating accurate information concerning some of the costs. the model developed utilizes non-linear programming.
THEORY OF CONSTRAINTS VERSUS OTHER COSTING METHODS: A MATTER OF SHORT OR LONG TERM TEORIA DAS RESTRI ES VERSUS OUTROS MéTODOS DE CUSTEIO: UMA QUEST O DE CURTO OU DE LONGO PRAZO
Samuel Cogan
Revista Universo Contábil , 2007,
Abstract: The Theory of Constraints (TOC) and Activity-based Costing (ABC), although opposite in their basic foundations, can concur in integration studies which attempt to show that these methods applied together perform better when compared to their individual use. As for that integration, a group of authors (CAMPBELL,1992; MAcARTHUR, 1993; HOLMEN, 1995; FRITZSCH, 1997) defends an idea of the difference between these two methodologies being a matter of the time horizon: TOC used in the short term and ABC in the long term. The present article’s objective is to show, through a numeric illustration, considerations of that group of studies. Therefore, the TOC decision making is compared with other costing methods: Absorption Costing, Activity-based Costing and Variable Costing. The data analysis permits to confirm that TOC has produced a better result than the other techniques, in the short term. In the long term, however, when idle capacities can be exploited fully in the absence of internal constraints, ABC proved to be the technique that leads to the best result. Keywords: Integration. Theory of Constraints. Activity-based Costing. A Teoria das Restri es (TOC) e o Custeio Baseado em Atividades (ABC), embora opostos em seus fundamentos básicos, podem se conciliar em estudos de integra o que buscam mostrar que juntos s o superiores à sua abordagem individual. No que se refere a essa integra o, um grupo de autores (CAMPBELL,1992; MAcARTHUR, 1993; HOLMEN, 1995; FRITZSCH, 1997) defende que a diferen a entre essas duas metodologias é uma quest o de horizonte de tempo: a Teoria das Restri es para o curto prazo e o Custeio Baseado em Atividades para o longo prazo. O presente artigo tem por objetivo mostrar, através de uma ilustra o numérica, as considera es desse grupo de estudos. Para tanto, a tomada de decis o da Teoria das Restri es é comparada com outros métodos de custeio: Custeio por Absor o Tradicional, Custeio Baseado em Atividades e o Custeio Variável. A análise dos dados obtidos permite confirmar que a Teoria das Restri es apresentou resultado melhor que as demais técnicas no curto prazo. No longo prazo, contudo, em que as capacidades n o usadas podem ser utilizadas em sua plenitude, n o existindo, pois, restri es internas, o Custeio Baseado em Atividades mostrou ser a técnica que conduz ao melhor resultado. Palavras-chave: Integra o. Teoria das Restri es. Custeio Baseado em Atividades.
Jóvenes contemporáneos: entre el trabajo emocional y estético en el mundo corporativo
Liuba, Kogan-Cogan
Boletín Científico Sapiens Research , 2012,
Abstract: In this research we examine the contemporary sociocultural context and its relationship with the corporal image that young women and males, students of the management and economic areas of a private university in Lima, consider “ideal”. Specifically, we focus on the type of corporal management that students consider to be important to help them gain access to the corporate environment in order to develop a successful career. That is, we want to know the meaning that young people who will form part of the political and economic elites of the country give to the relation between their bodies, super egos and their sociocultural environment. The results of this study are a product of two methodolog-ical approaches: the Q multivariable analysis allowed us to identify those factors that students of both sexes regarded to be important to manage their bodies as social capital. Then, we performed qualitative analysis of the information obtained in focus groups.
Failure of antibiotic treatment in microbial populations
Patrick De Leenheer,Nick Cogan
Quantitative Biology , 2008,
Abstract: The tolerance of bacterial populations to biocidal or antibiotic treatment has been well documented in both biofilm and planktonic settings. However, there is still very little known about the mechanisms that produce this tolerance. Evidence that small, non-mutant subpopulations of bacteria are not affected by antibiotic challenge has been accumulating and provides an attractive explanation for the failure of typical dosing protocols. Although a dosing challenge can kill all the susceptible bacteria, the remaining persister cells can serve as a source of population regrowth. We give a robust condition for the failure of a periodic dosing protocol for a general chemostat model, which supports the mathematical conclusions and simulations of an earlier, more specialized batch model. Our condition implies that the treatment protocol fails globally, in the sense that a mixed bacterial population will ultimately persist above a level that is independent of the initial composition of the population. We also give a sufficient condition for treatment success, at least for initial population compositions near the steady state of interest, corresponding to bacterial washout. Finally, we investigate how the speed at which the bacteria are wiped out depends on the duration of administration of the antibiotic. We find that this dependence is not necessarily monotone, implying that optimal dosing does not necessarily correspond to continuous administration of the antibiotic. Thus, genuine periodic protocols can be more advantageous in treating a wide variety of bacterial infections.
Hypereosinophilic syndromes
Florence E Roufosse, Michel Goldman, Elie Cogan
Orphanet Journal of Rare Diseases , 2007, DOI: 10.1186/1750-1172-2-37
Abstract: In this article, we have chosen to adopt the classification scheme proposed by Klion et al., on behalf of the Hypereosinophilic Syndromes Working Group that reached a consensus in Bern in 2005 [1]. Under the umbrella diagnosis of "Hypereosinophilic Syndromes", various disease presentations and pathogenic variants are divided in subgroups (see bullets below). This approach offers the advantage of providing physicians with the full array of differential diagnosis, once underlying diseases (parasitic, allergic, neoplastic etc.) classically known to be associated with hypereosinophilia are excluded by thorough patient evaluation. It provides a basis for developing a diagnostic and therapeutic management algorithm of chronic eosinophil-mediated disease.The following terms are currently used in medical literature to qualify different patient subsets among those fulfilling the diagnostic criteria of HES:? FIP1L1-PDGFRA(F/P)-associated HES, or F/P+ HES, for patients with clonal hypereosinophilia due to a sporadic hematopoi?tic stem cell chromosomal rearrangement resulting in fusion of two genes (FIP1L1 and PDGFRA) on 4q12; these patients are more appropriately classified as F/P+ chronic eosinophilic leukemia.? Chronic eosinophilic leukemia (CEL), for patients in whom clonality of eosinophils has been demonstrated (including those with the FIP1L1-PDGFRA fusion), or who present increased blasts; occasional reports indicate that some patients with CEL progress towards acute myeloid or eosinophilic leukemia.? Lymphocytic-HES (L-HES), for patients with chronic reactive (polyclonal) hypereosinophilia secondary to IL-5 over-production by T cells.? Myeloproliferative-HES (M-HES) may be used for patients with an array of clinical and biological features suggesting the possible existence of an underlying myeloproliferative disorder associated with hypereosinophilia, although underlying molecular defects are not detected (including increased serum vitamin B12, hepato- and/or splenomeg
Estimated Binding Energies of Drug-Like and Nondrug-Like Molecules in the Active Site of HIV-1 Integrase, 1BIS.pdb, and Two Mutant Models: Y143R and N155H  [PDF]
Julie B. Ealy, Noorhaan Abouomar, Justin Cogan, Paolo Flauta, Liliana Nassar, Matthew Mekolochik, Sarah Ramzy, Christopher Shannon, Habib Yazgi
Advances in Bioscience and Biotechnology (ABB) , 2017, DOI: 10.4236/abb.2017.85013
Abstract: Lipinski’s “Rule of Five” was introduced for predicting oral bioavailability to describe drug-like molecules. For the purpose of this research the rules were used to separate potential inhibitors of HIV-1 integrase (1BIS.pdb) into two groups: drug-like and nondrug-like. If one of Lipinski’s “Rule of Five” was not followed the potential inhibitor was classified as nondrug-like. Thirty molecules were identified from the literature, twenty-four drug-like and six nondrug-like, that were docked into the active site of 1BIS.pdb (considered the non-mutated protein) and two mutant models, Y143R and N155H. These are two of the mutations that have led to increased resistance to HIV-1 integrase drugs such as raltegravir and elvitegravir. The computational software, ICM-Pro (Molsoft L.L.C.), was used to determine the estimated binding energy (EBE) of the drug/protein complex. It was found that the nondrug-like molecules generally had a more negative EBE, that is, tighter binding with 1BIS. pdb, though there were several exceptions in the drug-like group. With the protein mutant model Y143R, the majority of drug-like (58%) and nondrug-like molecules (67%) had tighter binding. However, for the mutant model N155H, there was the same percent (46%) of drug-like molecules with tighter binding with the mutant model as with 1BIS.pdb. The drug-like molecules were used when there was a ≥1 kcal/mole difference between 1BIS.pdb and either of the two mutant models to suggest a pharmacophore with structural characteristics for an HIV-1 integrase inhibitor.
Identification and Characterisation of an Iron-Responsive Candidate Probiotic
Jennifer R. Bailey, Christopher S. J. Probert, Tristan A. Cogan
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026507
Abstract: Background Iron is an essential cofactor in almost all biological systems. The lactic acid bacteria (LAB), frequently employed as probiotics, are unusual in having little or no requirement for iron. Iron in the human body is sequestered by transferrins and lactoferrin, limiting bacterial growth. An increase in the availability of iron in the intestine by bleeding, surgery, or under stress leads to an increase in the growth and virulence of many pathogens. Under these high iron conditions, LAB are rapidly out-competed; for the levels of probiotic bacteria to be maintained under high iron conditions they must be able to respond by increasing growth rate to compete with the normal flora. Despite this, iron-responsive genera are poorly characterised as probiotics. Methodology/Principal Findings Here, we show that a panel of probiotics are not able to respond to increased iron availability, and identify an isolate of Streptococcus thermophilus that can increase growth rate in response to increased iron availability. The isolate of S. thermophilus selected was able to reduce epithelial cell death as well as NF-κB signalling and IL-8 production triggered by pathogens. It was capable of crossing an epithelial cell barrier in conjunction with E. coli and downregulating Th1 and Th17 responses in primary human intestinal leukocytes. Conclusions/Significance We propose that an inability to compete with potential pathogens under conditions of high iron availability such as stress and trauma may contribute to the lack of efficacy of many LAB-based probiotics in treating disease. Therefore, we offer an alternative paradigm which considers that probiotics should be able to be competitive during periods of intestinal bleeding, trauma or stress.
Genome-wide SNP identification in multiple morphotypes of allohexaploid tall fescue (Festuca arundinacea Schreb)
Melanie L Hand, Noel OI Cogan, John W Forster
BMC Genomics , 2012, DOI: 10.1186/1471-2164-13-219
Abstract: A bioinformatic pipeline was developed that successfully identified SNPs within genotypes from distinct tall fescue morphotypes, following the sequencing of 414 polymerase chain reaction (PCR) – generated amplicons using 454 GS FLX technology. Equivalent amplicon sets were derived from representative genotypes of each morphotype, including six Continental, five Mediterranean and one rhizomatous. A total of 8,584 and 2,292 SNPs were identified with high confidence within the Continental and Mediterranean morphotypes respectively. The success of the bioinformatic approach was demonstrated through validation (at a rate of 70%) of a subset of 141 SNPs using both SNaPshot? and GoldenGate? assay chemistries. Furthermore, the quantitative genotyping capability of the GoldenGate? assay revealed that approximately 30% of the putative SNPs were accessible to co-dominant scoring, despite the hexaploid genome structure. The sub-genome-specific origin of each SNP validated from Continental tall fescue was predicted using a phylogenetic approach based on comparison with orthologous sequences from predicted progenitor species.Using the appropriate bioinformatic approach, amplicon resequencing based on 454 GS FLX technology is an effective method for the identification of polymorphic SNPs within the genomes of Continental and Mediterranean tall fescue. The GoldenGate? assay is capable of high-throughput co-dominant SNP allele detection, and minimises the problems associated with SNP genotyping in a polyploid by effectively reducing the complexity to a diploid system. This SNP collection may now be refined and used in applications such as cultivar identification, genetic linkage map construction, genome-wide association studies and genomic selection in tall fescue. The bioinformatic pipeline described here represents an effective general method for SNP discovery within outbreeding allopolyploid species.
Metrics for nonlinear model updating in structural dynamics
Silva, Samuel da;Cogan, Scott;Foltête, Emmanuel;Buffe, Fabrice;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2009, DOI: 10.1590/S1678-58782009000100005
Abstract: the aim of this paper is to perform a comparative study between different distance measures or metrics for use in nonlinear model updating using vibration test data. four metrics derived from both frequency and time domain updating approaches are studied, including the harmonic balance method, the constitutive equation error, the restoring force surface and the karhunen-loève decomposition. in the first section, a benchmark model with local nonlinear stiffness is defined in order to illustrate each method. secondly, each nonlinear updating metric is succinctly reviewed. finally, the relative performances of the different metrics are investigated based on numerical simulations. these results allow us to characterize the applicability and limitations of the different approaches.
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