An amoeboid algorithm for shortest path in fuzzy weighted networks

Taking the uncertainty existing in edge weights of networks into consideration, finding shortest path in such fuzzy weighted networks has been widely studied in various practical applications. In this paper, an amoeboid algorithm is proposed, combing fuzzy sets theory with a path finding model inspired by an amoeboid organism, Physarum polycephalum. With the help of fuzzy numbers, uncertainty is well represented and handled in our algorithm. What's more, biological intelligence of Physarum polycephalum has been incorporate into the algorithm. A numerical example on a transportation network is demonstrated to show the efficiency and flexibility of our proposed amoeboid algorithm.

An improved physarum centrality measure for weighted networks

Identification of the most central node within a network is one of the primary problems in network analysis. Among various centrality measures for weighted networks, most are based on the assumption that information only spreads through the shortest paths. Then, a mathematical model of an amoeboid organism has been used by Physarum centrality to relax the assumption. However, its computational complexity is relatively high by finding competing paths between all pairs of nodes in networks. In this paper, with the idea of a ground node, an improved Physarum centrality is proposed by maintaining the feature of original measure with the performance is greatly enhanced. Examples and applications are given to show the efficiency and effectiveness of our proposed measure in weighted networks.

PhysarumSpreader: a new bio-Inspired methodology for identifying influential spreaders in complex networks

Identifying influential spreaders in networks, which contributes to optimizing the use of available resources and efficient spreading of information, is of great theoretical significance and practical value. A random-walk-based algorithm LeaderRank has been shown as an effective and efficient method in recognizing leaders in social network, which even outperforms the well-known PageRank method. As LeaderRank is initially developed for binary directed networks, further extensions should be studied in weighted networks. In this paper, a generalized algorithm PhysarumSpreader is proposed by combining LeaderRank with a positive feedback mechanism inspired from an amoeboid organism called Physarum Polycephalum. By taking edge weights into consideration and adding the positive feedback mechanism, PhysarumSpreader is applicable in both directed and undirected networks with weights. By taking two real networks for examples, the effectiveness of the proposed method is demonstrated by comparing with other standard centrality measures.

An amoeboid algorithm for solving linear transportation problem

Transportation Problem (TP) is one of the basic operational research problems, which plays an important role in many practical applications. In this paper, a bio-inspired mathematical model is proposed to handle the Linear Transportation Problem (LTP) in directed networks by modifying the original amoeba model Physarum Solver. Several examples are used to prove that the provided model can effectively solve Balanced Transportation Problem (BTP), Unbalanced Transportation Problem (UTP), especially the Generalized Transportation Problem (GTP), in a nondiscrete way. © 2013 Elsevier B.V. All rights reserved.

Sex, androgens, and whole-organism performance in an Australian lizard

Understanding underlying physiological differences between the sexes in circulating androgens and how hormonal variation affects morphology-performance relationships may help clarify the evolution of sexual dimorphism in diverse taxa. Using a widely distributed Australian lizard (Eulamprus quoyii) with weak sexual dimorphism and no dichromatism, we tested whether circulating androgens differed between the sexes and whether they covaried with morphological and performance traits (bite force, sprint speed, endurance). Males had larger head dimensions, stronger bite force, faster sprint speed, and longer endurance compared to females. We found that the sexes did not differ in androgen concentrations and that androgens were weakly associated with both morphological and performance traits. Interestingly, high circulating androgens showed a nonlinear relationship with bite force in males and not females, with this relationship possibly being related to alternative male reproductive tactics. Our results suggest that androgens are not strongly correlated with most performance and morphological traits, although they may play an important organizational role during the development of morphological traits, which could explain the differences in morphology and thus performance between the sexes. Differences in performance between the sexes suggest differential selection on these functional traits between males and females. © 2014 The Linnean Society of London.

C-direct: a family business

A business is a multifaceted organism; made up of mutually dependent employees whose connection to each other is largely dependant on their role within the entity. Being in a family is a very similar experience. So when family and business interact, managing both can be a challenge. This case study focuses on issues that contribute to a successful family business infrastructure, and the issues and trends that they identify as significant - for example, the importance of a succession plan within the family business environment.

Copper-dependent iron assimilation pathway in the model photosynthetic eukaryote chlamydomonas reinhardtii

The unicellular green alga Chlamydomonas reinhardtii is a valuable model for studying metal metabolism in a photosynthetic background. A search of the Chlamydomonas expressed sequence tag database led to the identification of several components that form a copper-dependent iron assimilation pathway related to the high-affinity iron uptake pathway defined originally for Saccharomyces cerevisiae. They include a multicopper ferroxidase (encoded by Fox1), an iron permease (encoded by Ftr1), a copper chaperone (encoded by Atx1), and a copper-transporting ATPase. A cDNA, Fer1, encoding ferritin for iron storage also was identified. Expression analysis demonstrated that Fox1 and Ftr1 were coordinately induced by iron deficiency, as were Atx1 and Fer1, although to lesser extents. In addition, Fox1 abundance was regulated at the posttranscriptional level by copper availability. Each component exhibited sequence relationship with its yeast, mammalian, or plant counterparts to various degrees; Atx1 of C. reinhardtii is also functionally related with respect to copper chaperone and antioxidant activities. Fox1 is most highly related to the mammalian homologues hephaestin and ceruloplasmin; its occurrence and pattern of expression in Chlamydomonas indicate, for the first time, a role for copper in iron assimilation in a photosynthetic species. Nevertheless, growth of C. reinhardtii under copper- and iron-limiting conditions showed that, unlike the situation in yeast and mammals, where copper deficiency results in a secondary iron deficiency, copper-deficient Chlamydomonas cells do not exhibit symptoms of iron deficiency. We propose the existence of a copper-independent iron assimilation pathway in this organism.

Phytophthora cinnamomi in native vegetation communities of southern Victoia - morphological variation and paragyny among isolates

Morphology has often been used as an indicator of variability within species. The present study investigated morphological and physiological characteristics of isolates of Phytophthora cinnamomi collected from diseased vegetation communities at Anglesea, Victoria, and isolates collected from other regions in the State. Characteristics studied included growth rate on potato-dextrose agar (PDA), corn-meal agar and V8-juice agar at 24°C, growth rate on V8 agar at 15°C, colony morphology on PDA, sporangial and gametangial morphology, sporangial production and mating type. Phenotypic variation was demonstrated in radial growth rate, colony morphology and sporangial dimensions. Sporangial and oogonial dimensions and sporangial production were not significantly different between isolates from different geographical regions. All isolates were found to be of the A2 mating type suggesting variation was derived asexually. Paragynal associations, in an organism characteristically defined as amphigynal, were observed following crossing with A1 isolates. This is the first such study undertaken in southern Victoria. The findings highlight the importance of appropriate management of an area of such high conservation value as the Anglesea Heath to contain the current infection and to prevent introduction of new isolates into the area.

The zebrafish spil promoter drives myeloid-specific expression in stable transgenic fish

The spi1 (pu.1) gene has recently been identified as a useful marker of early myeloid cells in zebrafish. To enhance the versatility of this organism as a model for studying myeloid development, the promoter of this gene has been isolated and characterized. Transient transgenesis revealed that a 5.3 kilobase promoter fragment immediately upstream of the spi1 coding sequence was sufficient to drive expression of enhanced green fluorescent protein (EGFP) in injected embryos in a manner that largely recapitulated the native spi1 gene expression pattern. This fragment was successfully used to produce a germ line transgenic line of zebrafish with EGFP-expressing myeloid cells. These TG(spi1:EGFP)pA301 transgenic zebrafish represent a valuable tool for further studies of myeloid development and its perturbation.

Harnessing zebrafish for the study of white blood cell development and its perturbation

Considerable progress has been made in understanding the molecular basis of normal white blood cell development and its perturbation in disease through the use of clinical studies and traditional animal and cell line models. Despite this, however, many questions are still being answered and white blood cell disorders, including leukemia and lymphoma, remain a significant health problem. The zebrafish (Danio rerio) has emerged as a powerful alternative vertebrate model for the study of development and disease. We review the recent application of zebrafish to the study of white blood cell development and its disruption, particularly leukemogenesis. Such studies have highlighted the overall conservation of these processes throughout vertebrates, and establish zebrafish as a useful experimental model. This organism is now poised to make an important contribution to our understanding of the underlying genetic control of white blood cell development and its disruption, as well as the identification of new therapeutic agents.

Hematopoietic perturbation in zebrafish expressing a tel-jak2a fusion

Objective
Various TEL-JAK2 fusions have been identified in patients with lymphoblastic and myeloid leukemias that result in constitutive activation of the JAK2 kinase domain. Such fusions can mediate factor-independent growth of hematopoietic cell lines and induction of malignancy in mouse models.
Materials and methods
To assess whether zebrafish could be utilized as a suitable model for the study of myeloid oncogenesis, we generated a zebrafish tel-jak2a fusion oncoprotein based on that seen in a case of chronic myeloid leukemia. This was transiently expressed in zebrafish embryos under the control of the spi1 promoter, which is strongly active in myeloid precursors.
Results
Visual, histological, and molecular analysis revealed disruption of normal embryonic hematopoiesis, including perturbation of the myeloid and erythroid lineages.
Conclusion
These results indicate that the zebrafish tel-jak2a oncoprotein is functional, and suggest that this organism will be useful for the experimental study of myeloid malignancy.

Culture and leadership in educational administration: a historical study of what was and what might have been

This paper examines the consequences for school leadership of the abandonment of Waller's insights into the school as a social organism and the embracing of the cult of efficiency as the foundation for the analysis of school culture. Tracing the separation of conception from execution, leadership from teaching, administration from education through the cult of professionalism and functionalist sociology, the paper argues that a more appropriate basis for understanding both leadership and the culture of the school can be derived from ethnographies of schooling which show the complex interactions of internal and external cultures in the construction of leadership and the culture of the school.

A whole body, in vivo, fatty A\acid balance method to quantify PUFA metabolism (desaturation, elongation and beta-oxidation)

Currently there are several contrasting methods utilized for estimating elongation and desaturation of fatty acids and their general metabolism. The majority of these methods involve an ex vivo approach, requiring expensive and sophisticated equipment, likely to result in considerable variation in enzyme activity between and within species. In the present paper we introduce a further development of the whole-body fatty acid balance method for the estimation of the elongation and desaturation of fatty acids. This method though receiving considerable attention because of its simplicity and reliability has yet to be presented in detail. Theoretically, the whole-body fatty acid balance method can potentially be applied to any organism and requires little more than a gas chromatography unit for fatty acid analysis and elementary calculations. As such in this paper we attempt to spell out in detail the theoretical basis and the methods of application drawing specific examples. Using the present method it is possible to measure the fate of individual fatty acids towards desaturation, elongation and oxidation and calculate the elongase, Δ-6 desaturase and Δ-5 desaturase activities.