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Sample records for achaete-scute complex as-c

  1. The achaete-scute complex in Diptera: patterns of noncoding sequence evolution.

    PubMed

    Negre, B; Simpson, P

    2015-10-01

    The achaete-scute complex (AS-C) has been a useful paradigm for the study of pattern formation and its evolution. achaete-scute genes have duplicated and evolved distinct expression patterns during the evolution of cyclorraphous Diptera. Are the expression patterns in different species driven by conserved regulatory elements? If so, when did such regulatory elements arise? Here, we have sequenced most of the AS-C of the fly Calliphora vicina (including the genes achaete, scute and lethal of scute) to compare noncoding sequences with known cis-regulatory sequences in Drosophila. The organization of the complex is conserved with respect to Drosophila species. There are numerous small stretches of conserved noncoding sequence that, in spite of high sequence turnover, display binding sites for known transcription factors. Synteny of the blocks of conserved noncoding sequences is maintained suggesting not only conservation of the position of regulatory elements but also an origin prior to the divergence between these two species. We propose that some of these enhancers originated by duplication with their target genes.

  2. Achaete-scute complex homologue-1 promotes development of laryngocarcinoma via facilitating the epithelial-mesenchymal transformation.

    PubMed

    Ma, Huaci; Du, Xiaodong; Zhang, Shu; Wang, Qiang; Yin, Yong; Qiu, Xiaoxia; Da, Peng; Yue, Huijun; Wu, Hao; Xu, Fenglei

    2017-06-01

    Laryngeal cancer is one of the most common fatal cancers among head and neck carcinomas, whose mechanism, however, remains unclear. The proneural basic-helix-loop-helix protein achaete-scute complex homologue-1, a member of the basic helix-loop-helix family, plays a very important role in many cancers. This study aims to explore the clinical value and mechanism of achaete-scute complex homologue-1 in laryngeal cancer. Methods including Cell Counting Kit-8, flow cytometry, Transwell invasion assays, and scratch assay were adopted to further explore the bio-function of achaete-scute complex homologue-1, whose expression was examined in fresh and paraffin chip of laryngeal carcinoma tissues by means of western blot and immunohistochemistry, after the interference of achaete-scute complex homologue-1; achaete-scute complex homologue-1, an overexpression in laryngeal carcinoma whose carcinogenicity potential was confirmed via western blot, was correlative with T classification (p = 0.002), histological differentiation (p = 0.000), lymph node metastasis (p = 0.000), and poor survival (p = 0.000). Multivariate analysis shows that achaete-scute complex homologue-1 overexpression is an independent prognostic factor unfavorable to laryngeal carcinoma patients (p = 0.000). Moreover, knocking down achaete-scute complex homologue-1 expression could significantly suppress the proliferation, migration, and invasion of laryngeal carcinoma cell in vitro and disorder epithelial-mesenchymal transformation-associated protein expression. Achaete-scute complex homologue-1 plays an important role in the genesis and progression of laryngeal carcinoma and may act as a potential biomarker for therapeutic target and prognostic prediction.

  3. Systematic analysis of the achaete-scute complex-like gene signature in clinical cancer patients

    PubMed Central

    Wang, Chih-Yang; Shahi, Payam; Huang, John Ting Wei; Phan, Nam Nhut; Sun, Zhengda; Lin, Yen-Chang; Lai, Ming-Derg; Werb, Zena

    2017-01-01

    The achaete-scute complex-like (ASCL) family, also referred to as ‘achaete-scute complex homolog’ or ‘achaete-scute family basic helix-loop-helix transcription factor’, is critical for proper development of the nervous system and deregulation of ASCL plays a key role in psychiatric and neurological disorders. The ASCL family consists of five members, namely ASCL1, ASCL2, ASCL3, ASCL4 and ASCL5. The ASCL1 gene serves as a potential oncogene during lung cancer development. There is a correlation between increased ASCL2 expression and colon cancer development. Inhibition of ASCL2 reduced cellular proliferation and tumor growth in xenograft tumor experiments. Although previous studies demonstrated involvement of ASCL1 and ASCL2 in tumor development, little is known on the remaining ASCL family members and their potential effect on tumorigenesis. Therefore, a holistic approach to investigating the expression of ASCL family genes in diverse types of cancer may provide new insights in cancer research. In this study, we utilized a web-based microarray database (Oncomine; www.oncomine.org) to analyze the transcriptional expression of the ASCL family in clinical cancer and normal tissues. Our bioinformatics analysis revealed the potential involvement of multiple ASCL family members during tumor onset and progression in multiple types of cancer. Compared to normal tissue, ASCL1 exhibited a higher expression in cancers of the lung, pancreas, kidney, esophagus and head and neck, whereas ASCL2 exhibited a high expression in cancers of the breast, colon, stomach, lung, head and neck, ovary and testis. ASCL3, however, exhibited a high expression only in breast cancer. Interestingly, ASCL1 expression was downregulated in melanoma and in cancers of the bladder, breast, stomach and colon. ASCL2 exhibited low expression levels in sarcoma, melanoma, brain and prostate cancers. Reduction in the expression of ASCL3 was detected in lymphoma, bladder, cervical, kidney and

  4. Systematic analysis of the achaete-scute complex-like gene signature in clinical cancer patients.

    PubMed

    Wang, Chih-Yang; Shahi, Payam; Huang, John Ting Wei; Phan, Nam Nhut; Sun, Zhengda; Lin, Yen-Chang; Lai, Ming-Derg; Werb, Zena

    2017-01-01

    The achaete-scute complex-like (ASCL) family, also referred to as 'achaete-scute complex homolog' or 'achaete-scute family basic helix-loop-helix transcription factor', is critical for proper development of the nervous system and deregulation of ASCL plays a key role in psychiatric and neurological disorders. The ASCL family consists of five members, namely ASCL1, ASCL2, ASCL3, ASCL4 and ASCL5. The ASCL1 gene serves as a potential oncogene during lung cancer development. There is a correlation between increased ASCL2 expression and colon cancer development. Inhibition of ASCL2 reduced cellular proliferation and tumor growth in xenograft tumor experiments. Although previous studies demonstrated involvement of ASCL1 and ASCL2 in tumor development, little is known on the remaining ASCL family members and their potential effect on tumorigenesis. Therefore, a holistic approach to investigating the expression of ASCL family genes in diverse types of cancer may provide new insights in cancer research. In this study, we utilized a web-based microarray database (Oncomine; www.oncomine.org) to analyze the transcriptional expression of the ASCL family in clinical cancer and normal tissues. Our bioinformatics analysis revealed the potential involvement of multiple ASCL family members during tumor onset and progression in multiple types of cancer. Compared to normal tissue, ASCL1 exhibited a higher expression in cancers of the lung, pancreas, kidney, esophagus and head and neck, whereas ASCL2 exhibited a high expression in cancers of the breast, colon, stomach, lung, head and neck, ovary and testis. ASCL3, however, exhibited a high expression only in breast cancer. Interestingly, ASCL1 expression was downregulated in melanoma and in cancers of the bladder, breast, stomach and colon. ASCL2 exhibited low expression levels in sarcoma, melanoma, brain and prostate cancers. Reduction in the expression of ASCL3 was detected in lymphoma, bladder, cervical, kidney and epithelial

  5. The complex tale of the achaete-scute complex: a paradigmatic case in the analysis of gene organization and function during development.

    PubMed

    García-Bellido, Antonio; de Celis, Jose F

    2009-07-01

    The achaete-scute gene complex (AS-C) contains four genes encoding transcription factors of the bHLH family, achaete, scute, lethal of scute, and asense located in 40 kb of DNA containing multiple cis-regulatory position-specific enhancers. These genes play a key role in the commitment of epidermal cells toward a neural fate, promoting the formation of both sensory organs in the peripheral nervous system (bristles) of the adult and of neuroblasts in the central nervous system of the embryo. The analysis of the AS-C initially focused on the variations in positional specificity of effects of achaete (ac) and scute (sc) alleles on macrochaete bristle pattern in the Drosophila adult epidermis, and from there it evolved as a key entry point into understanding the molecular bases of pattern formation and cell commitment. In this perspective, we describe how the study of the AS-C has contributed to the understanding of eukaryotic gene organization and the dissection of the developmental mechanisms underlying pattern formation.

  6. Extensive Linkage Disequilibrium in the Achaete-Scute Complex of Drosophila Melanogaster

    PubMed Central

    Macpherson, J. N.; Weir, B. S.; Leigh-Brown, A. J.

    1990-01-01

    We have analyzed the level of gametic association between restriction map variants in a sample of 44 X chromosomes from a natural population of Drosophila melanogaster. Of 21 pairwise tests involving 7 restriction map polymorphisms in the yellow-achaete-scute complex, 17 were found to be significant, including some between restriction sites over 80 kb apart. Three-way linkage disequilibria and their variances were also estimated for all 35 three-way comparisons between these loci. Twelve such tests were found to be significant, again spanning distances of up to 80 kb on the restriction map. Only 9 of a possible 128 haplotypes were represented in the sample and 8 of these could be linked together by changes at a single site. The strength of these associations at y-ac-sc is unusual by comparison with studies on other regions of the genome of D. melanogaster, and is consistent with the very low level of recombination which has been reported for the complex. However, our estimate of nucleotide diversity in the region is not significantly different from those made for some other loci in this species. PMID:2121592

  7. Molecular analysis of the asense gene, a member of the achaete-scute complex of Drosophila melanogaster, and its novel role in optic lobe development.

    PubMed Central

    González, F; Romani, S; Cubas, P; Modolell, J; Campuzano, S

    1989-01-01

    The achaete-scute complex (AS-C) comprises five genetic regions: achaete, scute (sc) alpha, lethal of sc, sc beta and sc gamma. Each region promotes the determination and positional specification of different, but partially overlapping, subsets of neural elements of Drosophila. In this work, we report a molecular characterization of the sc gamma region. It comprises 22 kb of DNA and contains two transcription units, only one of which, named asense (ase), seems involved in neurogenesis. ase encodes a protein that shares with other three AS-C proteins a domain containing a helix--loop--helix motif characteristic of a group of DNA-binding proteins. In the embryo, ase is expressed in neural precursor cells, a pattern consistent with the known requirement of sc gamma for the development of the larval nervous system. In late third-instar larvae, the gene is expressed in developing structures of the central nervous system (CNS), namely the anlagen of the optic lobes and in many cells, including neuroblasts, of the central brain and ventral ganglia. Its removal leads to anatomical defects in the adult optic lobes. This is the first demonstration of a role for the AS-C in the development of the adult CNS. Images PMID:2510998

  8. Chrysin suppresses the achaete-scute complex-like1 and alters the neuroendocrine phenotype of carcinoids

    PubMed Central

    Somnay, Yash R.; Dull, Barbara Zarebczan; Eide, Jacob; Jaskula-Sztul, Renata; Chen, Herbert

    2015-01-01

    Carcinoids are neuroendocrine neoplasms that cause significant morbidity and mortality, and for which few effective therapies are available. Given the recent identification of the anti-cancer flavonoid chrysin, we sought to investigate its therapeutic potential in carcinoids. Here, we report chrysin’s ability to modulate the achaete-scute complex-like1 (ASCL1), a neuroendocrine-specific transcription factor highly implicated in the malignant phenotype of carcinoids and other neuroendocrine cancers. Moreover, we elucidate the role of ASCL1 in carcinoid growth and bioactivity. Treatment of two carcinoid cell lines (BON and H727) with varying chrysin concentrations suppressed cell proliferation, while reducing expression of ASCL1 and the neuroendocrine biomarker chromogranin A (CgA), demonstrated by Western blotting. Propidium iodide and PE AnnexinV/7-AAD staining and sorting following chrysin treatment revealed S/G2 phase arrest and apoptosis, respectively. This was corroborated by chrysin-induced cleavage of caspase-3 and PARP and activation of p21Waf1/Cip1. Furthermore, direct ASCL1 knockdown with an ASCL1-specific small interfering RNA inhibited CgA and synaptophysin expression as well as carcinoid proliferation, while also reducing cyclin B1 and D1, and increasing p21Waf1/Cip1 and p27Kip1 expression, suggesting an arrest of the cell-cycle. Collectively, these findings warrant the deliberation of targeted ASCL1 suppression by chrysin or other agents as a therapeutic approach for carcinoid management. PMID:26403073

  9. The Enhancer of split and Achaete-Scute complexes of Drosophilids derived from simple ur-complexes preserved in mosquito and honeybee

    PubMed Central

    Schlatter, Rebekka; Maier, Dieter

    2005-01-01

    Background In Drosophila melanogaster the Enhancer of split-Complex [E(spl)-C] consists of seven highly related genes encoding basic helix-loop-helix (bHLH) repressors and intermingled, four genes that belong to the Bearded (Brd) family. Both gene classes are targets of the Notch signalling pathway. The Achaete-Scute-Complex [AS-C] comprises four genes encoding bHLH activators. The question arose how these complexes evolved with regard to gene number in the evolution of insects concentrating on Diptera and the Hymenoptera Apis mellifera. Results In Drosophilids both gene complexes are highly conserved, spanning roughly 40 million years of evolution. However, in species more diverged like Anopheles or Apis we find dramatic differences. Here, the E(spl)-C consists of one bHLH (mβ) and one Brd family member (mα) in a head to head arrangement. Interestingly in Apis but not in Anopheles, there are two more E(spl) bHLH like genes within 250 kb, which may reflect duplication events in the honeybee that occurred independently of that in Diptera. The AS-C may have arisen from a single sc/l'sc like gene which is well conserved in Apis and Anopheles and a second ase like gene that is highly diverged, however, located within 50 kb. Conclusion E(spl)-C and AS-C presumably evolved by gene duplication to the nowadays complex composition in Drosophilids in order to govern the accurate expression patterns typical for these highly evolved insects. The ancestral ur-complexes, however, consisted most likely of just two genes: E(spl)-C contains one bHLH member of mβ type and one Brd family member of mα type and AS-C contains one sc/l'sc and a highly diverged ase like gene. PMID:16293187

  10. Small cell lung cancer, an epithelial to mesenchymal transition (EMT)-like cancer: significance of inactive Notch signaling and expression of achaete-scute complex homologue 1.

    PubMed

    Ito, Takaaki; Kudoh, Shinji; Ichimura, Takaya; Fujino, Kosuke; Hassan, Wael Ahmed Maher Abdo; Udaka, Naoko

    2017-01-01

    Small cell lung cancer (SCLC) is one of the most malignant neoplasms in common human cancers. The tumor is composed of small immature-looking cells with a round or fusiform shape, which possesses weak adhesion features among them, suggesting that SCLC shows the morphological characteristics of epithelial to mesenchymal transition (EMT). SCLC is characterized by high metastatic and recurrent rates, sensitivity to the initial chemotherapy, and easy acquirement of chemoresistance afterwards. These characters may be related to the EMT phenotype of SCLC. Notch signaling is an important signaling pathway, and could have roles in regulating neuroendocrine differentiation, proliferation, cell adhesion, EMT, and chemoresistance. Notch1 is usually absent in SCLC in vivo, but could appear after chemotherapy. Notch1 can enhance cell adhesion by induction of E-cadherin in SCLC, which indicates mesenchymal to epithelial transition. On the other hand, achaete-scute complex homologue 1 (ASCL1), negatively regulated by Notch signaling, is a lineage-specific gene of SCLC, and functions to promote neuroendocrine differentiation as well as EMT. ASCL1-transfected adenocarcinoma cell lines induced neuroendocrine phenotypes and lost epithelial cell features. SCLC is characterized by neuroendocrine differentiation and EMT-like features, which could be produced by inactive Notch signaling and ASCL1 expression. In addition, chemical and radiation treatments can activate Notch signaling, which suppress neuroendocrine differentiation and induces chemoradioresistance, accompanied by secession from EMT. Thus, the status of Notch signaling and ASCL1 expression may determine the cell behaviors of SCLC partly through modifying EMT phenotypes.

  11. Identification of a human achaete-scute homolog highly expressed in neuroendocrine tumors.

    PubMed Central

    Ball, D W; Azzoli, C G; Baylin, S B; Chi, D; Dou, S; Donis-Keller, H; Cumaraswamy, A; Borges, M; Nelkin, B D

    1993-01-01

    Basic helix-loop-helix transcription factors of the achaete-scute family are instrumental in Drosophila neurosensory development and are candidate regulators of development in the mammalian central nervous system and neural crest. We report the isolation and initial characterization of a human achaete-scute homolog that is highly expressed in two neuroendocrine cancers, medullary thyroid cancer (MTC) and small cell lung cancer (SCLC). The human gene, which we have termed human achaete-scute homology 1 (hASH1), was cloned from a human MTC cDNA library. It encodes a predicted protein of 238 aa that is 95% homologous to mammalian achaete-scute homolog (MASH) 1, a rodent basic helix-loop-helix factor. The 57-residue basic helix-loop-helix domain is identical to that in the rodent gene, and the basic and helical regions, excluding the loop, are 72-80% identical to Drosophila achaete-scute family members. The proximal coding region of the hASH1 cDNA contains a striking 14-copy repeat of the triplet CAG that exhibits polymorphism in human genomic DNA. Thus, hASH1 is a candidate locus for disease-causing mutations via triplet repeat amplification. Analysis of rodent-human somatic cell hybrids permitted assignment of hASH1 to human chromosome 12. Northern blots revealed hASH1 transcripts in RNA from a human MTC cell line, two fresh MTC tumors, fetal brain, and three lines of human SCLC. In contrast, cultured lines of non-SCLC lung cancers and a panel of normal adult human tissues showed no detectable hASH1 transcripts. Expression of hASH1 may provide a useful marker for cancers with neuroendocrine features and may contribute to the differentiation and growth regulation of these cells. Images Fig. 3 Fig. 4 Fig. 5 PMID:8390674

  12. Developmental Analysis of the Achaete-Scute System of DROSOPHILA MELANOGASTER

    PubMed Central

    García-Bellido, A.; Santamaria, P.

    1978-01-01

    The interpretation of the wild-type function of a gene depends on our knowledge of the phenotype caused by its absence. We have first defined the genetic extent of the achaete-scute system by studying the phenotype of different terminal and intercalary deficiencies including these genes. When these deficiencies were lethal, we have defined the phenoeffective phase of lethality and studied their phenotype in genetic mosaics (gynandromorphs and mitotic recombination clones). The achaete-scute system affects two functions, one necessary for the differentiation of the embryonic (central?) nervous system and the other necessary for the differentiation of peripheral nervous elements of the chaetes and sensillae of the adult cuticle. The possibility that these functions correspond to differential expression of a single mechanism is discussed. PMID:17248807

  13. Nematostella vectensis achaete-scute homolog NvashA regulates embryonic ectodermal neurogenesis and represents an ancient component of the metazoan neural specification pathway

    PubMed Central

    Layden, Michael J.; Boekhout, Michiel; Martindale, Mark Q.

    2012-01-01

    achaete-scute homologs (ash) regulate neural development in all bilaterian model animals indicating that they represent a component of the ancestral neurogenic pathway. We test this by investigating four ash genes during development of a basal metazoan, the cnidarian sea anemone Nematostella vectensis. Spatiotemporal expression of ash genes in the early embryo and larval stages suggests that they regulate neurogenesis. More specifically, NvashA is co-expressed with neural genes in the embryonic ectoderm. Knockdown of NvashA results in decreased expression of eight neural markers, including the six novel neural targets identified here. Conversely, overexpression of NvashA induces increased expression of all eight genes, but only within their normal axial domains. Overexpression of NvashB-D differentially increases expression of NvashA targets. The expression patterns and differential ability of ash genes to regulate neural gene expression reveals surprising molecular complexity in these ‘simple’ animals. These data suggest that achaete-scute homologs functioned in the ancestral metazoan neurogenic pathway and provide a foundation to investigate further the evolution of neurogenesis and the origin of complex central nervous systems. PMID:22318631

  14. The Expression and Function of the Achaete-Scute Genes in Tribolium castaneum Reveals Conservation and Variation in Neural Pattern Formation and Cell Fate Specification

    NASA Technical Reports Server (NTRS)

    Wheeler, Scott R.; Carrico, Michelle L.; Wilson, Beth A.; Brown, Susan J.; Skeath, James B.

    2003-01-01

    SUMMARY The study of achaete-scute (ac/sc) genes has recently become a paradigm to understand the evolution and development of the arthropod nervous system. We describe the identification and characterization of the ache genes in the coleopteran insect species Tribolium castaneum. We have identified two Tribolium ache genes - achaete-scute homolog (Tc-ASH) a proneural gene and asense (Tc-ase) a neural precursor gene that reside in a gene complex. Focusing on the embryonic central nervous system we fmd that Tc-ASH is expressed in all neural precursors and the proneural clusters from which they segregate. Through RNAi and misexpression studies we show that Tc-ASH is necessary for neural precursor formation in Triboliurn and sufficient for neural precursor formation in Drosophila. Comparison of the function of the Drosophila and Triboliurn proneural ac/sc genes suggests that in the Drosophila lineage these genes have maintained their ancestral function in neural precursor formation and have acquired a new role in the fate specification of individual neural precursors. Furthermore, we find that Tc-use is expressed in all neural precursors suggesting an important and conserved role for asense genes in insect nervous system development. Our analysis of the Triboliurn ache genes indicates significant plasticity in gene number, expression and function, and implicates these modifications in the evolution of arthropod neural development.

  15. The expression and function of the achaete-scute genes in Tribolium castaneum reveals conservation and variation in neural pattern formation and cell fate specification

    NASA Technical Reports Server (NTRS)

    Wheeler, Scott R.; Carrico, Michelle L.; Wilson, Beth A.; Brown, Susan J.; Skeath, James B.

    2003-01-01

    The study of achaete-scute (ac/sc) genes has recently become a paradigm to understand the evolution and development of the arthropod nervous system. We describe the identification and characterization of the ac/sc genes in the coleopteran insect species Tribolium castaneum. We have identified two Tribolium ac/sc genes - achaete-scute homolog (Tc-ASH) a proneural gene and asense (Tc-ase) a neural precursor gene that reside in a gene complex. Focusing on the embryonic central nervous system we find that Tc-ASH is expressed in all neural precursors and the proneural clusters from which they segregate. Through RNAi and misexpression studies we show that Tc-ASH is necessary for neural precursor formation in Tribolium and sufficient for neural precursor formation in Drosophila. Comparison of the function of the Drosophila and Tribolium proneural ac/sc genes suggests that in the Drosophila lineage these genes have maintained their ancestral function in neural precursor formation and have acquired a new role in the fate specification of individual neural precursors. Furthermore, we find that Tc-ase is expressed in all neural precursors suggesting an important and conserved role for asense genes in insect nervous system development. Our analysis of the Tribolium ac/sc genes indicates significant plasticity in gene number, expression and function, and implicates these modifications in the evolution of arthropod neural development.

  16. The Expression and Function of the Achaete-Scute Genes in Tribolium castaneum Reveals Conservation and Variation in Neural Pattern Formation and Cell Fate Specification

    NASA Technical Reports Server (NTRS)

    Wheeler, Scott R.; Carrico, Michelle L.; Wilson, Beth A.; Brown, Susan J.; Skeath, James B.

    2003-01-01

    SUMMARY The study of achaete-scute (ac/sc) genes has recently become a paradigm to understand the evolution and development of the arthropod nervous system. We describe the identification and characterization of the ache genes in the coleopteran insect species Tribolium castaneum. We have identified two Tribolium ache genes - achaete-scute homolog (Tc-ASH) a proneural gene and asense (Tc-ase) a neural precursor gene that reside in a gene complex. Focusing on the embryonic central nervous system we fmd that Tc-ASH is expressed in all neural precursors and the proneural clusters from which they segregate. Through RNAi and misexpression studies we show that Tc-ASH is necessary for neural precursor formation in Triboliurn and sufficient for neural precursor formation in Drosophila. Comparison of the function of the Drosophila and Triboliurn proneural ac/sc genes suggests that in the Drosophila lineage these genes have maintained their ancestral function in neural precursor formation and have acquired a new role in the fate specification of individual neural precursors. Furthermore, we find that Tc-use is expressed in all neural precursors suggesting an important and conserved role for asense genes in insect nervous system development. Our analysis of the Triboliurn ache genes indicates significant plasticity in gene number, expression and function, and implicates these modifications in the evolution of arthropod neural development.

  17. The expression and function of the achaete-scute genes in Tribolium castaneum reveals conservation and variation in neural pattern formation and cell fate specification

    NASA Technical Reports Server (NTRS)

    Wheeler, Scott R.; Carrico, Michelle L.; Wilson, Beth A.; Brown, Susan J.; Skeath, James B.

    2003-01-01

    The study of achaete-scute (ac/sc) genes has recently become a paradigm to understand the evolution and development of the arthropod nervous system. We describe the identification and characterization of the ac/sc genes in the coleopteran insect species Tribolium castaneum. We have identified two Tribolium ac/sc genes - achaete-scute homolog (Tc-ASH) a proneural gene and asense (Tc-ase) a neural precursor gene that reside in a gene complex. Focusing on the embryonic central nervous system we find that Tc-ASH is expressed in all neural precursors and the proneural clusters from which they segregate. Through RNAi and misexpression studies we show that Tc-ASH is necessary for neural precursor formation in Tribolium and sufficient for neural precursor formation in Drosophila. Comparison of the function of the Drosophila and Tribolium proneural ac/sc genes suggests that in the Drosophila lineage these genes have maintained their ancestral function in neural precursor formation and have acquired a new role in the fate specification of individual neural precursors. Furthermore, we find that Tc-ase is expressed in all neural precursors suggesting an important and conserved role for asense genes in insect nervous system development. Our analysis of the Tribolium ac/sc genes indicates significant plasticity in gene number, expression and function, and implicates these modifications in the evolution of arthropod neural development.

  18. The identification and expression of achaete-scute genes in the branchiopod crustacean Triops longicaudatus.

    PubMed

    Wheeler, Scott R; Skeath, James B

    2005-06-01

    The achaete-scute (ac/sc) genes are a highly conserved family of transcription factors that play important roles in the development of neural cells in both vertebrates and invertebrates. As such, the study of arthropod ac/sc gene expression during neurogenesis has become a model system for investigating the evolution of neural patterning. To date, ac/sc gene expression has been investigated in insects, chelicerates, and myriapods. Here we present the identification of two ac/sc genes from the branchiopod crustacean Triops longicaudatus. Triops longicaudatus achaete-scute homologs1 and 2 (Tl-ASH1 and Tl-ASH2) exhibit dynamic and distinct expression profiles during Triops neurogenesis. Tl-ASH1 expression initiates in nearly all cells of the neurogenic region and subsequently in clusters of cells evenly spaced along the length of the developing limbs. In contrast, Tl-ASH2 initiates expression after Tl-ASH1. In the CNS, only a subset of Tl-ASH1 cells appears to express Tl-ASH2. Similarly, in the PNS individual Tl-ASH2 positive cells appear to arise from the clusters of Tl-ASH1 expressing cells. Shortly after activating Tl-ASH2 expression, these cells enlarge and divide. The expression dynamics of ac/sc genes in Triops parallel those observed in insects and contrasts with those found in chelicerates and myriapods.

  19. Distribution and function of splash, an achaete-scute homolog in the adult olfactory organ of the Caribbean spiny lobster Panulirus argus

    PubMed Central

    Tadesse, Tizeta; Schmidt, Manfred; Walthall, William W.; Tai, Phang C.; Derby, Charles D.

    2011-01-01

    achaete-scute complex (ASC) genes, which encode basic helix-loop-helix transcription factors, regulate embryonic and adult neurogenesis in many animals. In adult arthropods, including crustaceans, ASC homologs have been identified but rarely functionally characterized. We took advantage of the recently identified crustacean homolog, splash (spiny lobster achaete scute homolog), in the olfactory organ of the Caribbean spiny lobster Panulirus argus to examine its role in adult neurogenesis. We tested the hypothesis that splash is associated with but not restricted to sensory neuron formation in the olfactory organ, the antennular lateral flagellum (LF), of adult spiny lobsters. We demonstrated splash labeling in epithelial cells across LF developmental zones (i.e., proliferation and mature zones), in auxiliary cells surrounding dendrites of olfactory receptor neurons (ORNs), and in immature and mature ORNs, but not in granulocytes or chromatophores. Since ORN proliferation varies with molt stage, we examined splash expression across molt stages and found that molt stage affected splash expression in the ORN mature zone but not in the proliferation zone. In vivo incorporation of bromodeoxyuridine (BrdU) showed no correlation in the cellular pattern of splash expression and BrdU labeling. The intensity of splash labeling was dramatically enhanced in the proliferation zones following LF damage, suggesting enhanced splash expression during repair and/or regeneration. We conclude that splash is not closely associated with the formation of sensory neurons under normal physiological conditions, and we propose that splash is involved in repair and regeneration. We also propose that splash has additional roles other than neurogenesis in adult crustaceans. PMID:21394934

  20. Achaete-Scute Homolog 1 Expression Controls Cellular Differentiation of Neuroblastoma

    PubMed Central

    Kasim, Mumtaz; Heß, Vicky; Scholz, Holger; Persson, Pontus B.; Fähling, Michael

    2016-01-01

    Neuroblastoma, the major cause of infant cancer deaths, results from fast proliferation of undifferentiated neuroblasts. Treatment of high-risk neuroblastoma includes differentiation with retinoic acid (RA); however, the resistance of many of these tumors to RA-induced differentiation poses a considerable challenge. Human achaete-scute homolog 1 (hASH1) is a proneural basic helix-loop-helix transcription factor essential for neurogenesis and is often upregulated in neuroblastoma. Here, we identified a novel function for hASH1 in regulating the differentiation phenotype of neuroblastoma cells. Global analysis of 986 human neuroblastoma datasets revealed a negative correlation between hASH1 and neuron differentiation that was independent of the N-myc (MYCN) oncogene. Using RA to induce neuron differentiation in two neuroblastoma cell lines displaying high and low levels of hASH1 expression, we confirmed the link between hASH1 expression and the differentiation defective phenotype, which was reversed by silencing hASH1 or by hypoxic preconditioning. We further show that hASH1 suppresses neuronal differentiation by inhibiting transcription at the RA receptor element. Collectively, our data indicate hASH1 to be key for understanding neuroblastoma resistance to differentiation therapy and pave the way for hASH1-targeted therapies for augmenting the response of neuroblastoma to differentiation therapy. PMID:28066180

  1. Achaete-Scute Homologue-1 Tapers Neuroendocrine Cell Differentiation in Lungs after Exposure to Naphthalene

    PubMed Central

    Jensen-Taubman, Sandra; Wang, Xiao-Yang; Linnoila, R. Ilona

    2010-01-01

    The basic helix-loop-helix transcription factor achaete-scute homologue-1 (ASH1) plays a critical role in regulating the neuroendocrine (NE) phenotype in normal and neoplastic lung. Transgenic (TG) mice that constitutively express human ASH1 (hASH1) under control of the Clara cell 10-kDa protein (CC10) promoter in non-NE airway lining cells display progressive epithelial hyperplasia and bronchiolar metaplasia or bronchiolization of the alveoli (BOA). However, little is known about the involvement of hASH1 in regeneration of the conducting airway. In this study, we investigated the impact of hASH1 on airway cell injury and repair in the TG mice following an intraperitoneal injection of naphthalene, which specifically ablates bronchiolar Clara cells and induces pulmonary NE cell hyperplasia. We discovered an overall attenuation of NE maturation coupled with increased proliferation in TG mice during post-naphthalene repair. In addition, BOA lesions revealed enhanced epithelial cell proliferation while preserving Clara cell markers CC10 and the principal naphthalene-metabolizing enzyme cytochrome P4502F2. These data suggest that ASH1 may play an important role in maintaining a progenitor phenotype that promotes renewal of both NE and epithelial cells. Moreover, ASH1 may propagate a stem cell microenvironment in BOA where epithelium becomes resistant to naphthalene toxicity. PMID:20554700

  2. Translational regulation of the human achaete-scute homologue-1 by fragile X mental retardation protein.

    PubMed

    Fähling, Michael; Mrowka, Ralf; Steege, Andreas; Kirschner, Karin M; Benko, Edgar; Förstera, Benjamin; Persson, Pontus B; Thiele, Bernd J; Meier, Jochen C; Scholz, Holger

    2009-02-13

    Fragile X syndrome is a common inherited cause of mental retardation that results from loss or mutation of the fragile X mental retardation protein (FMRP). In this study, we identified the mRNA of the basic helix-loop-helix transcription factor human achaete-scute homologue-1 (hASH1 or ASCL1), which is required for normal development of the nervous system and has been implicated in the formation of neuroendocrine tumors, as a new FMRP target. Using a double-immunofluorescent staining technique we detected an overlapping pattern of both proteins in the hippocampus, temporal cortex, subventricular zone, and cerebellum of newborn rats. Forced expression of FMRP and gene silencing by small interference RNA transfection revealed a positive correlation between the cellular protein levels of FMRP and hASH1. A luciferase reporter construct containing the 5'-untranslated region of hASH1 mRNA was activated by the full-length FMRP, but not by naturally occurring truncated FMR proteins, in transient co-transfections. The responsible cis-element was mapped by UV-cross-linking experiments and reporter mutagenesis assays to a (U)(10) sequence located in the 5'-untranslated region of the hASH1 mRNA. Sucrose density gradient centrifugation revealed that hASH1 transcripts were translocated into a translationally active polysomal fraction upon transient transfection of HEK293 cells with FMRP, thus indicating translational activation of hASH1 mRNA. In conclusion, we identified hASH1 as a novel downstream target of FMRP. Improved translation efficiency of hASH1 mRNA by FMRP may represent an important regulatory switch in neuronal differentiation.

  3. Achaete-scute homolog 1 as a marker of poorly differentiated neuroendocrine carcinomas of different sites: a validation study using immunohistochemistry and quantitative real-time polymerase chain reaction on 335 cases.

    PubMed

    La Rosa, Stefano; Marando, Alessandro; Gatti, Gaia; Rapa, Ida; Volante, Marco; Papotti, Mauro; Sessa, Fausto; Capella, Carlo

    2013-07-01

    Neuroendocrine carcinomas show overlapping morphological and immunohistochemical features independently of their site of origin, which makes identification of the primary location problematic when they are diagnosed as metastases of unknown origin. Neuroendocrine carcinomas are easily morphologically differentiated from neuroendocrine tumors in surgical material, although this distinction can be difficult when using small biopsy specimens. The diagnostic usefulness of different transcription factors as site-specific markers or as discriminating markers between neuroendocrine carcinomas and neuroendocrine tumors has been previously studied with sometimes contradictory results. In this respect, the role of achaete-scute homolog 1 has been poorly investigated, although some recent findings demonstrate its expression in neuroendocrine carcinomas. Using immunohistochemistry and quantitative real-time polymerase chain reaction, we investigated the expression of achaete-scute homolog 1 in 335 neuroendocrine neoplasms (194 neuroendocrine carcinomas and 141 neuroendocrine tumors) of different sites, to check its possible utility as diagnostic marker. High concordance between immunohistochemical and molecular findings was found. Achaete-scute homolog 1 expression was identified in 82% of lung neuroendocrine carcinomas and 70% of extrapulmonary neuroendocrine carcinomas. Achaete-scute homolog 1 was not detected in any gastroenteropancreatic neuroendocrine tumor and was found in only a minority of lung carcinoids. The diagnostic sensitivity and specificity of achaete-scute homolog 1 expression were 82.4% and 89.7% in distinguishing neuroendocrine carcinomas from neuroendocrine tumors of the lung, 40.6% and 100% to differentiate extrapulmonary neuroendocrine carcinomas from neuroendocrine tumors, and 82.4% and 59.4% in distinguishing lung from extrapulmonary neuroendocrine carcinomas. Our data suggest that achaete-scute homolog 1 is not a site-specific marker. However, achaete-scute

  4. DNA binding and transcriptional regulatory activity of mammalian achaete-scute homologous (MASH) proteins revealed by interaction with a muscle-specific enhancer.

    PubMed

    Johnson, J E; Birren, S J; Saito, T; Anderson, D J

    1992-04-15

    The MASH genes are vertebrate homologues of achaete-scute, genes required for neuronal determination in Drosophila. The sequence of MASH1 and MASH2 contains a basic helix-loop-helix (bHLH) motif that is present in other transcriptional regulators such as MyoD and E12. In the absence of an authentic target for the MASH proteins, we examined their DNA binding and transcriptional regulatory activity by using a binding site (the E box) from the muscle creatine kinase (MCK) gene, a target of MyoD. Like myogenic bHLH proteins, the MASH proteins form heterooligomers with E12 that bind the MCK E box with high affinity in vitro. Unexpectedly, however, MASH1 and MASH2 also activate transcription of both exogenous and endogenous MCK in transfected C3H/10T1/2 fibroblasts. However, they do not induce myogenesis. Myogenic activity is not exclusively a property of the MyoD basic region, as substitution of this domain fails to confer myogenic activity on MASH1. These data suggest that different bHLH proteins may activate overlapping but distinct sets of target genes in the same cell type.

  5. Co-expression of Achaete-Scute Homologue-1 and Calcitonin Gene-Related Peptide during NNK-Induced Pulmonary Neuroendocrine Hyperplasia and Carcinogenesis in Hamsters

    PubMed Central

    Naizhen, Xu; Linnoila, R. Ilona; Kimura, Shioko

    2016-01-01

    Achaete-scute homologue-1 or ASCL1 (MASH1, hASH1) plays roles in neural development and pulmonary neuroendocrine (NE) differentiation, and it is expressed in certain lung cancers. This study was aimed to assess whether and/or how ASCL1 plays a role in 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced pulmonary NE hyperplasia and carcinogenesis in hamsters. Hamsters were injected 3 times weekly with either NNK or solvent alone (control) for treatment periods of 6 and 24 weeks, both without and with 6-week recovery. Immunohistochemical analysis was carried out to examine the expressions of ASCL1, CGRP (calcitonin gene-related peptide), secretoglobin SCGB1A1 (club [Clara] cell specific 10 kD protein, CC10, CCSP), synaptophysin (SYP), and PCNA (proliferating cell nuclear antigen). The number of ASCL1-expressing NE foci per airway increased from 0.8 in controls to 1.6 and 2.0 during NNK exposure for 6 and 24 weeks, respectively, and the number of cells per foci doubled after NNK exposure. Most ASCL1-expressing cells in NEBs (neuroepithelial bodies) were also CGRP immunoreactive; NNK enhanced this co-expression with CGRP, a NE marker with known proliferation-promoting properties. NNK also increased PCNA expression within NE foci. NNK-induced tumors showed no immunoreactivity for NE markers. This study confirms ASCL1 as an excellent marker for pulmonary NE cells and demonstrates CGRP co-expression in ASCL1-positive NEB cells participating in NNK-induced NE hyperplasia. PMID:27877229

  6. Induction and repression of mammalian achaete-scute homologue (MASH) gene expression during neuronal differentiation of P19 embryonal carcinoma cells.

    PubMed

    Johnson, J E; Zimmerman, K; Saito, T; Anderson, D J

    1992-01-01

    MASH1 and MASH2, mammalian homologues of the Drosophila neural determination genes achaete-scute, are members of the basic helix-loop-helix (bHLH) family of transcription factors. We show here that murine P19 embryonal carcinoma cells can be used as a model system to study the regulation and function of these genes. MASH1 and MASH2 display complementary patterns of expression during the retinoic-acid-induced neuronal differentiation of P19 cells. MASH1 mRNA is undetectable in undifferentiated P19 cells but is induced to high levels by retinoic acid coincident with neuronal differentiation. In contrast, MASH2 mRNA is expressed in undifferentiated P19 cells and is repressed by retinoic acid treatment. These complementary expression patterns suggest distinct functions for MASH1 and MASH2 in development, despite their sequence homology. In retinoic-acid-treated P19 cells, MASH1 protein expression precedes and then overlaps expression of neuronal markers. However, MASH1 is expressed by a smaller proportion of cells than expresses such markers. MASH1 immunoreactivity is not detected in differentiated cells displaying a neuronal morphology, suggesting that its expression is transient. These features of MASH1 expression are similar to those observed in vivo, and suggest that P19 cells represent a good model system in which to study the regulation of this gene. Forced expression of MASH1 was achieved in undifferentiated P19 cells by transfection of a cDNA expression construct. The transfected cells expressing exogenous MASH1 protein contained E-box-binding activity that could be super-shifted by an anti-MASH1 antibody, but exhibited no detectable phenotypic changes. Thus, unlike myogenic bHLH genes, such as MyoD, which are sufficient to induce muscle differentiation, expression of MASH1 appears insufficient to promote neurogenesis.

  7. The expression of proprotein convertase PACE4 is highly regulated by Hash-2 in placenta: possible role of placenta-specific basic helix-loop-helix transcription factor, human achaete-scute homologue-2.

    PubMed

    Koide, Shizuyo; Yoshida, Ichiro; Tsuji, Akihiko; Matsuda, Yoshiko

    2003-09-01

    PACE4 is a member of the mammalian subtilisin-like proprotein convertase (SPC) family, which contribute to the activation of transforming growth factor (TGF) beta family proteins. We previously reported that PACE4 is highly expressed in syncytiotrophoblasts of human placenta [Tsuji et al. (2003) BIOCHIM: Biophys. Acta 1645, 95-104]. In this study, the regulatory mechanism for PACE4 expression in placenta was analyzed using a human placental choriocarcinoma cell line, BeWo cells. Promoter analysis indicated that an E-box cluster (E4-E9) in the 5'-flanking region of the PACE4 gene acts as a negative regulatory element. The binding of human achaete-scute homologue 2 (Hash-2) to the E-box cluster was shown by gel mobility-shift assay. The overexpression of Hash-2 caused a marked decrease in PACE4 gene expression. When BeWo cells were grown under low oxygen (2%) conditions, the expression of Hash-2 decreased, while that of PACE4 increased. In both cases, other SPCs, such as furin, PC5/6, and PC7/8, were not affected. Further, PACE4 expression was found to be developmentally regulated in rat placenta. By in situ hybridization, Mash-2 (mammalian achaete-scute homologue 2) mRNA was found to be expressed in the spongiotrophoblast layer where PACE4 was not expressed. In contrast, the PACE4 mRNA was expressed mainly in the labyrinthine layer where Mash-2 was not detected. These results suggest that PACE4 expression is down-regulated by Hash-2/Mash-2 in both human and rat placenta and that many bioactive proteins might be regulated by PACE4 activity.

  8. Hypoxia prevents induction of aromatase expression in human trophoblast cells in culture: potential inhibitory role of the hypoxia-inducible transcription factor Mash-2 (mammalian achaete-scute homologous protein-2).

    PubMed

    Jiang, B; Kamat, A; Mendelson, C R

    2000-10-01

    The human placenta has a remarkable capacity to aromatize C19-steroids, produced by the fetal adrenals, to estrogens. This reaction is catalyzed by aromatase P450 (P450arom), encoded by the CYP19 gene. In placenta, CYP19 gene expression is restricted to the syncytiotrophoblast layer. Cytotrophoblasts isolated from human placenta, when placed in monolayer culture in 20% O2, spontaneously fuse to form syncytiotrophoblast. These morphological changes are associated with a marked induction of aromatase activity and CYP19 gene expression. When cytotrophoblasts are cultured in an atmosphere containing 2% O2, they manifest increased rates of DNA synthesis and fail to fuse and form syncytiotrophoblast. The objective of the present study was to utilize cytotrophoblasts isolated from midterm human placenta to analyze the effects of O2 on CYP19 gene expression and the molecular mechanisms that mediate these effects. We observed that when trophoblast cells were maintained in 2% O2, there was only a modest induction of CYP19 expression as a function of time in culture, and aromatase activity was barely detectable. However, when cytotrophoblasts that had been maintained in 2% O2 for 3 days were placed in a 20% O2 environment, there was a rapid onset of cell fusion and induction of P450arom mRNA and aromatase activity. In addition, mRNAs for the helix-loop-helix factors Mash-2 (mammalian achaete-scute homologous protein-2) and Id1 (inhibitor of differentiation 1) were readily detectable in freshly isolated cytotrophoblasts and were markedly decreased upon differentiation to syncytiotrophoblast in 20% O2. By contrast, when cytotrophoblasts were cultured in 2% O2, mRNA levels for Mash-2 and Id1 remained elevated. Interestingly, overexpression of Mash-2 in primary cultures of human trophoblast cells markedly inhibited cell fusion and the spontaneous induction of P450arom mRNA levels and caused a marked decrease in expression of co-transfected fusion gene constructs containing either

  9. Characterization of the placenta specific bovine mammalian achaete scute-like homologue 2 (Mash2) gene.

    PubMed

    Arnold, D R; Lefebvre, R; Smith, L C

    2006-01-01

    Mash2, a basic helix-loop-helix transcription factor, stimulates mononucleate trophoblast cell proliferation and inhibits giant/binucleate cell formation. In mice, Mash2 is a maternally expressed imprinted gene. Regulation of bovine Mash2 is unclear due to limited genetic knowledge. Our objectives were to clone and characterize bovine Mash2 and evaluate its imprinting status by utilizing Bos taurus taurus and Bos taurus indicus interspecies crossing. Bovine Mash2 mRNA shares 78% and 70% homology with human and mouse Mash2, with the DNA binding domain (88%) and bHLH region (95%) being highly conserved. Expression of Mash2 mRNA was seen exclusively in cotyledonary areas of the placenta. The greatest abundance of Mash2 mRNA was in day 17 filamentous embryos, during the time of rapid trophoblast proliferation. Reduction in Mash2 mRNA abundance was detected in day 8 parthenogenetic blastocysts suggesting paternal regulation of gene expression. Prior to implantation (days 8 and 17), Mash2 mRNA appears to have biallelic expression, but is paternally silenced after implantation (days 40 and 60). In conclusion, the Mash2 is highly conserved across species and is specifically expressed in the bovine placenta. Bovine Mash2 appears to be maternally expressed after implantation, but the paternal genome plays a role in regulating expression.

  10. The cell survival pathways of the primordial RNA–DNA complex remain conserved in the extant genomes and may function as proto-oncogenes

    PubMed Central

    2015-01-01

    Malignantly transformed (cancer) cells of multicellular hosts, including human cells, operate activated biochemical pathways that recognizably derived from unicellular ancestors. The descendant heat shock proteins of thermophile archaea now chaperon oncoproteins. The ABC cassettes of toxin-producer zooxantella Symbiodinia algae pump out the cytoplasmic toxin molecules; malignantly transformed cells utilize the derivatives of these cassettes to get rid of chemotherapeuticals. High mobility group helix–loop–helix proteins, protein arginine methyltransferases, proliferating cell nuclear antigens, and Ki-67 nuclear proteins, that protect and repair DNA in unicellular life forms, support oncogenes in transformed cells. The cell survival pathways of Wnt–β-catenin, Hedgehog, PI3K, MAPK–ERK, STAT, Ets, JAK, Pak, Myb, achaete scute, circadian rhythms, Bruton kinase and others, which are physiological in uni- and early multicellular eukaryotic life forms, are constitutively encoded in complex oncogenic pathways in selected single cells of advanced multicellular eukaryotic hosts. Oncogenes and oncoproteins in advanced multicellular hosts recreate selected independently living and immortalized unicellular life forms, which are similar to extinct and extant protists. These unicellular life forms are recognized at the clinics as autologous “cancer cells”. PMID:25883792

  11. Prepatterning the Drosophila notum: the three genes of the iroquois complex play intrinsically distinct roles.

    PubMed

    Ikmi, Aissam; Netter, Sophie; Coen, Dario

    2008-05-15

    The Drosophila thorax exhibits 11 pairs of large sensory organs (macrochaetes) identified by their unique position. Remarkably precise, this pattern provides an excellent model system to study the genetic basis of pattern formation. In imaginal wing discs, the achaete-scute proneural genes are expressed in clusters of cells that prefigure the positions of each macrochaete. The activities of prepatterning genes provide positional cues controlling this expression pattern. The three homeobox genes clustered in the iroquois complex (araucan, caupolican and mirror) are such prepattern genes. mirror is generally characterized as performing functions predominantly different from the other iroquois genes. Conversely, araucan and caupolican are described in previous studies as performing redundant functions in most if not all processes in which they are involved. We have addressed the question of the specific role of each iroquois gene in the prepattern of the notum and we clearly demonstrate that they are intrinsically different in their contribution to this process: caupolican and mirror, but not araucan, are required for the neural patterning of the lateral notum. However, when caupolican and/or mirror expression is reduced, araucan loss of function has an effect on thoracic bristles development. Moreover, the overexpression of araucan is able to rescue caupolican loss of function. We conclude that, although retaining some common functionalities, the Drosophila iroquois genes are in the process of diversification. In addition, caupolican and mirror are required for stripe expression and, therefore, to specify the muscular attachment sites prepattern. Thus, caupolican and mirror may act as common prepattern genes for all structures in the lateral notum.

  12. Proneural gene self-stimulation in neural precursors: an essential mechanism for sense organ development that is regulated by Notch signaling.

    PubMed

    Culí, J; Modolell, J

    1998-07-01

    To learn about the acquisition of neural fate by ectodermal cells, we have analyzed a very early sign of neural commitment in Drosophila, namely the specific accumulation of achaete-scute complex (AS-C) proneural proteins in the cell that becomes a sensory organ mother cell (SMC). We have characterized an AS-C enhancer that directs expression specifically in SMCs. This enhancer promotes Scute protein accumulation in these cells, an event essential for sensory organ development in the absence of other AS-C genes. Interspecific sequence comparisons and site-directed mutagenesis show the presence of several conserved motifs necessary for enhancer action, some of them binding sites for proneural proteins. These and other data indicate that the enhancer mediates scute self-stimulation, although only in the presence of additional activating factors, which most likely interact with conserved motifs reminiscent of NF-kappaB-binding sites. Cells neighboring the SMC do not acquire the neural fate because the Notch signaling pathway effectors, the Enhancer of split bHLH proteins, block this proneural gene self-stimulatory loop, possibly by antagonizing the action on the enhancer of the NF-kappaB-like factors or the proneural proteins. These data suggest a mechanism for SMC committment.

  13. The specificity of proneural genes in determining Drosophila sense organ identity.

    PubMed

    Jarman, A P; Ahmed, I

    1998-08-01

    The proneural genes (atonal and the genes of the achaete-scute complex (AS-C)) are required for the selection of sense organ precursors. They also endow these precursors with sense organ subtype information. In most of the ectoderm, atonal is required for precursors of chordotonal sense organs, whereas AS-C are required for those of most external sense organs, such as bristles. To address the question of how proneural genes influence subtype identity, we have made use of the Gal4/UAS system of misexpression. Unlike previous misexpression experiments, we found that under specific conditions of misexpression, atonal shows high subtype specificity of ectopic sense organ formation. Moreover, atonal can even transform wild-type external sense organs to chordotonal organs, although scute cannot perform the reciprocal transformation. Our evidence demonstrates that atonal's subtype determining role is not to activate directly chordotonal fate, but to repress the activation of cut, a gene that is necessary for external sense organ fate, thereby freeing its precursors to follow the alternative chordotonal organ fate.

  14. A model study of the morphogenesis of D. melanogaster mechanoreceptors: the central regulatory circuit.

    PubMed

    Golubyatnikov, Vladimir P; Bukharina, Tatyana A; Furman, Dagmara P

    2015-02-01

    Macrochaetes (large bristles) are sensor organs of the Drosophila peripheral nervous system with a function of mechanoreceptors. An adult mechanoreceptor comprises four specialized cells: shaft (trichogen), socket (tormogen), neuron, and glial cell (thecogen). All these cells originate from a single cell, the so-called sensor organ precursor (SOP) cell. Separation of the SOP cell from the encompassing cells of the imaginal disc initiates a multistage process of sensory organ development. A characteristic feature of the SOP cell is the highest amount of the proneural proteins AS-C as compared with the encompassing ectodermal cells. The accumulation of proneural proteins and maintenance of their amount in the SOP cell at a necessary level is provided by the gene network with the achaete-scute gene complex (AS-C) as its key component. The activity of this complex is controlled by the central regulatory circuit (CRC). The CRC comprises the genes hairy, senseless (sens), charlatan (chn), scratch (scrt), daughterless (da), extramacrochaete (emc), and groucho (gro), coding for the transcription factors involved in the system of direct links and feedbacks and implementation of activation-repression relationships between the CRC components. The gene phyllopod (phyl), involved in degradation of the AS-C proteins, is also associated with the CRC functioning. In this paper, we propose a mathematical model for the CRC functioning as a regulator of the amount of proneural AS-C proteins in the SOP cell taking into account their degradation. The modeling has demonstrated that a change in the amount of proneural proteins in the SOP cell is stepwise rather than strictly monotonic. This prediction can be tested experimentally.

  15. Structure-based design of platinum(II) complexes as c-myc oncogene down-regulators and luminescent probes for G-quadruplex DNA.

    PubMed

    Wang, Ping; Leung, Chung-Hang; Ma, Dik-Lung; Yan, Siu-Cheong; Che, Chi-Ming

    2010-06-18

    A series of platinum(II) complexes with tridentate ligands was synthesized and their interactions with G-quadruplex DNA within the c-myc gene promoter were evaluated. Complex 1, which has a flat planar 2,6-bis(benzimidazol-2-yl)pyridine (bzimpy) scaffold, was found to stabilize the c-myc G-quadruplex structure in a cell-free system. An in silico G-quadruplex DNA model has been constructed for structure-based virtual screening to develop new Pt(II)-based complexes with superior inhibitory activities. By using complex 1 as the initial structure for hit-to-lead optimization, bzimpy and related 2,6-bis(pyrazol-3-yl)pyridine (dPzPy) scaffolds containing amine side-chains emerge as the top candidates. Six of the top-scoring complexes were synthesized and their interactions with c-myc G-quadruplex DNA have been investigated. The results revealed that all of the complexes have the ability to stabilize the c-myc G-quadruplex. Complex 3 a ([Pt(II)L2R](+); L2=2,6-bis[1-(3-piperidinepropyl)-1H-enzo[d]imidazol-2-yl]pyridine, R=Cl) displayed the strongest inhibition in a cell-free system (IC(50)=2.2 microM) and was 3.3-fold more potent than that of 1. Complexes 3 a and 4 a ([Pt(II)L3R](+); L3=2,6-bis[1-(3-morpholinopropyl)-1H-pyrazol-3-yl]pyridine, R=Cl) were found to effectively inhibit c-myc gene expression in human hepatocarcinoma cells with IC(50) values of approximately 17 microM, whereas initial hit 1 displayed no significant effect on gene expression at concentrations up to 50 microM. Complexes 3 a and 4 a have a strong preference for G-quadruplex DNA over duplex DNA, as revealed by competition dialysis experiments and absorption titration; 3 a and 4 a bind G-quadruplex DNA with binding constants (K) of approximately 10(6)-10(7) dm(3) mol(-1), which are at least an order of magnitude higher than the K values for duplex DNA. NMR spectroscopic titration experiments and molecular modeling showed that 4 a binds c-myc G-quadruplex DNA through an external end-stacking mode at

  16. Enhancer-promoter communication mediated by Chip during Pannier-driven proneural patterning is regulated by Osa.

    PubMed

    Heitzler, Pascal; Vanolst, Luc; Biryukova, Inna; Ramain, Philippe

    2003-03-01

    The GATA factor Pannier activates proneural achaete/scute (ac/sc) expression during development of the sensory organs of Drosophila through enhancer binding. Chip bridges Pannier with the (Ac/Sc)-Daughterless heterodimers bound to the promoter and facilitates the enhancer-promoter communication required for proneural development. We show here that this communication is regulated by Osa, which is recruited by Pannier and Chip. Osa belongs to Brahma chromatin remodeling complexes and we show that Osa negatively regulates ac/sc. Consequently, Pannier and Chip also play an essential role during repression of proneural gene expression. Our study suggests that altering chromatin structure is essential for regulation of enhancer-promoter communication.

  17. Morphogenesis of Drosophila melanogaster macrochaetes: cell fate determination for bristle organ.

    PubMed

    Furman, D P; Bukharina, T A

    2012-01-01

    Formation of specialized spatial structures comprising various cell types is most important in the ontogenesis of multicellular organisms. An example is the D. melanogaster bristle organs. Bristles (micro- and macrochaetes) are external sensory organs, elements of the peripheral nervous system, playing the role of mechanoreceptors. Their comparatively simple organization comprising only four specialized cells and a common origin of these cells make macrochaetes a convenient model for studying cell differentiation. The four cells forming bristle organ result from two successive divisions of a single cell, sensory organ precursor (SOP) cell. The number of macrochaetes on drosophila body corresponds to the number of SOP cells. The morphogenesis of macrochaetes comprises three stages, the first two determining a neural fate of the cells. The third stage is cell specialization into components of the bristle organ-neuron, thecogen, tormogen, and trichogen. Development of each bristle commences from segregation of proneural clusters, of 20-30 cells, from the massif of undifferentiated cells of the wing imaginal disc. At this stage, each cluster cell can potentially become a SOP cell. At the second stage, the only SOP cell and its position are determined within each cluster. Finally, two asymmetric divisions of the SOP cell with subsequent differentiation of the daughter cells gives the bristle organ. Several dozens genes are involved in the control of macrochaete morphogenesis. The main component of this system is the proneural genes of achaete-scute complex (AS-C). An increased content of proneural proteins fundamentally distinguished the cells that will follow the neural developmental pathway from the disc epidermal cells. A local AS-C expression, initiated at specified disc sites by specific transcription factors, determines the number and topology of proneural clusters. The expression of AS-C genes, continuing in the cells of the cluster, increases the difference in

  18. Toutatis, a TIP5-related protein, positively regulates Pannier function during Drosophila neural development.

    PubMed

    Vanolst, Luc; Fromental-Ramain, Catherine; Ramain, Philippe

    2005-10-01

    The GATA factor Pannier (Pnr) activates proneural expression through binding to a remote enhancer of the achaete-scute (ac-sc) complex. Chip associates both with Pnr and with the (Ac-Sc)-Daughterless heterodimer bound to the ac-sc promoters to give a proneural complex that facilitates enhancer-promoter communication during development. Using a yeast two-hybrid screening, we have identified Toutatis (Tou), which physically interacts with both Pnr and Chip. Loss-of-function and gain-of-function experiments indicate that Tou cooperates with Pnr and Chip during neural development. Tou shares functional domains with chromatin remodelling proteins, including TIP5 (termination factor TTFI-interacting protein 5) of NoRC (nucleolar remodelling complex), which mediates repression of RNA polymerase 1 transcription. In contrast, Tou acts positively to activate proneural gene expression. Moreover, we show that Iswi associates with Tou, Pnr and Chip, and is also required during Pnr-driven neural development. The results suggest that Tou and Iswi may belong to a complex that directly regulates the activity of Pnr and Chip during enhancer-promoter communication, possibly through chromatin remodelling.

  19. Complexity.

    PubMed

    Gómez-Hernández, J Jaime

    2006-01-01

    It is difficult to define complexity in modeling. Complexity is often associated with uncertainty since modeling uncertainty is an intrinsically difficult task. However, modeling uncertainty does not require, necessarily, complex models, in the sense of a model requiring an unmanageable number of degrees of freedom to characterize the aquifer. The relationship between complexity, uncertainty, heterogeneity, and stochastic modeling is not simple. Aquifer models should be able to quantify the uncertainty of their predictions, which can be done using stochastic models that produce heterogeneous realizations of aquifer parameters. This is the type of complexity addressed in this article.

  20. Tat-PTD-Modified Oncolytic Adenovirus Driven by the SCG3 Promoter and ASH1 Enhancer for Neuroblastoma Therapy

    PubMed Central

    Jin, Chuan; Yu, Di; Čančer, Matko; Nilsson, Berith; Leja, Justyna

    2013-01-01

    Abstract Secretogranin III (SGC3) belongs to the granin family and is highly expressed in endocrine and neural tissues. The human SCG3 promoter has not yet been characterized. We identified that a 0.5-kb DNA fragment upstream of the SCG3 gene can selectively drive transgene expression in neuroblastoma cell lines. The strength of transgene expression was further increased, with specificity maintained, by addition of the human achaete-scute complex homolog 1 (ASH1) enhancer. We developed an oncolytic serotype 5-based adenovirus, in which the SCG3 promoter and ASH1 enhancer drive E1A gene expression. The virus was further modified with a cell-penetrating peptide (Tat-PTD) in the viral capsid, which we have previously shown results in increased adenovirus transduction efficiency of many neuroblastoma cell lines. The virus, Ad5PTD(ASH1-SCG3-E1A), shows selective and efficient killing of neuroblastoma cell lines in vitro, including cisplatin-, etoposide-, and doxorubicin-insensitive neuroblastoma cells. Furthermore, it delays tumor growth and thereby prolonged survival for nude mice harboring subcutaneous human neuroblastoma xenograft. In conclusion, we report a novel oncolytic adenovirus with potential use for neuroblastoma therapy. PMID:23889332

  1. EZH2 promotes progression of small cell lung cancer by suppressing the TGF-β-Smad-ASCL1 pathway

    PubMed Central

    Murai, Fumihiko; Koinuma, Daizo; Shinozaki-Ushiku, Aya; Fukayama, Masashi; Miyaozono, Kohei; Ehata, Shogo

    2015-01-01

    Transforming growth factor-β (TGF-β) induces apoptosis in many types of cancer cells and acts as a tumor suppressor. We performed a functional analysis of TGF-β signaling to identify a molecular mechanism that regulated survival in small cell lung cancer cells. Here, we found low expression of TGF-β type II receptor (TβRII) in most small cell lung cancer cells and tissues compared to normal lung epithelial cells and normal lung tissues, respectively. When wild-type TβRII was overexpressed in small cell lung cancer cells, TGF-β suppressed cell growth in vitro and tumor formation in vivo through induction of apoptosis. Components of polycomb repressive complex 2, including enhancer of zeste 2 (EZH2), were highly expressed in small cell lung cancer cells; this led to epigenetic silencing of TβRII expression and suppression of TGF-β-mediated apoptosis. Achaete-scute family bHLH transcription factor 1 (ASCL1; also known as ASH1), a Smad-dependent target of TGF-β, was found to induce survival in small cell lung cancer cells. Thus, EZH2 promoted small cell lung cancer progression by suppressing the TGF-β-Smad-ASCL1 pathway. PMID:27462425

  2. Modulation of pulmonary neuroendocrine cells in idiopathic interstitial pneumonia.

    PubMed

    Ito, T; Ogura, T; Ogawa, N; Udaka, N; Hayashi, H; Inayama, Y; Yazawa, T; Kitamura, H

    2002-10-01

    In order to reveal modulation of the number of pulmonary neuroendocrine cells (PNEC) in interstitial lung diseases and to clarify significance of cell proliferation activity in occurrence of PNEC, we counted airway PNEC of the patients of idiopathic interstitial pneumonia, secondary interstitial pneumonia and control lungs, and compared the number of PNEC with airway Ki-67 labeling. The lung tissue samples were obtained by video-assisted thoracoscopic surgery from 22 patients with usual interstitial pneumonia (UIP), 7 with non-specific interstitial pneumonia (NSIP), 8 with chronic hypersensitivity pneumonia (CHP), 13 with collagen vascular disease (CVD), and were compared with age-matched control lungs. The tissues were immunostained for chromogranin A and for Ki-67. Average incidence of bronchiolar PNEC in normal, UIP, NSIP, CHP, CVD lungs was 0.169%, 0.348%, 0.326%, 0.175% and 0.201%, respectively, and average Ki-67 labeling index in them was 0.241%, 1.186%, 1.605%, 1.058%, and 2.353%, respectively. And, in UIP lungs, PNEC incidence or Ki-67 labeling index was different according to pathological lesions. Thus, PNEC increase in the bronchiole of UIP, and the incidence of PNEC varies according to degree of activity of epithelial cell proliferation probably related to epithelial cell injury. Moreover, enhanced expression of human homolog of achaete-scute complex (hASH1) mRNA in UIP lungs suggests that hASH1 could play roles in the regulation of PNEC.

  3. Differentiation: A Central Topic in Developmental and Cell Biology

    NASA Astrophysics Data System (ADS)

    Müller, W. A.

    The concept of "differentiation" encompasses all processes leading to differently specialized cell types, beginning with the progressive divergence of developmental pathways and ending with the successive programming and final elaboration of each particular cell type. Guidance and positional information are provided by external cues, by differentially allotted cytoplasmic determinants such as mRNA for transcription factors, and by cascades of intercellular signals. Eventually cell type specific selector genes, such as the muscle cell determining MyoD/myogenin genes and neural key genes (e.g., achaete scute-C, neurogenin), are switched on which control entire sets of subordinate effector genes. In multiplying cells "cell heredity" based on an epigenetic cellular memory enables transmission of the cell type determining program from parental to daughter cells. This memory can be based on autocatalytic self-activation of cell type specific selector genes and on the enduring action of gene groups such as the Polycomb and thrithorax complexes that code for proteins which bind to DNA sequences called cellular memory modules. These modules confer permanent accessibility (potentiation) or inaccessibility (silencing) upon many different gene loci on the chromosomes.

  4. Uncovering stem cell differentiation factors for salivary gland regeneration by quantitative analysis of differential proteomes

    PubMed Central

    Park, Yun-Jong; Koh, Jin; Kwon, Jin Teak; Park, Yong-Seok; Yang, Lijun; Cha, Seunghee

    2017-01-01

    Severe xerostomia (dry mouth) compromises the quality of life in patients with Sjögren’s syndrome or radiation therapy for head and neck cancer. A clinical management of xerostomia is often unsatisfactory as most interventions are palliative with limited efficacy. Following up our previous study demonstrating that mouse BM-MSCs are capable of differentiating into salivary epithelial cells in a co-culture system, we further explored the molecular basis that governs the MSC reprogramming by utilizing high-throughput iTRAQ-2D-LC-MS/MS-based proteomics. Our data revealed the novel induction of pancreas-specific transcription factor 1a (PTF1α), muscle, intestine and stomach expression-1 (MIST-1), and achaete-scute complex homolog 3 (ASCL3) in 7 day co-cultured MSCs but not in control MSCs. More importantly, a common notion of pancreatic-specific expression of PTF1 α was challenged for the first time by our verification of PTF1 α expression in the mouse salivary glands. Furthermore, a molecular network simulation of our selected putative MSC reprogramming factors demonstrated evidence for their perspective roles in salivary gland development. In conclusion, quantitative proteomics with extensive data analyses narrowed down a set of MSC reprograming factors potentially contributing to salivary gland regeneration. Identification of their differential/synergistic impact on MSC conversion warrants further investigation. PMID:28158262

  5. Do Recurved Sensory Organs in Drosophila Form Through a Turing-Type Bifurcation?

    NASA Astrophysics Data System (ADS)

    Zhu, Huifeng

    2009-03-01

    We study the recurved bristles on Drosophila wing margin of wild-type and mutant.The expression levels of the achaete-scute complex protein determine the epidermal or neural fate of a pro-neural cell. In wide-type flies, the development ends in a state where a recurved bristle grows out nearly every fifth cell. Recent experiments have shown that the frequency of recurved bristles can be changed by adjusting the mean concentrations of the zinc-finger transcription factor Senseless and the microRNA miR-9a. With reduced levels of miR-9a, mutant flies grow regular organization of recurved bristles, but with a lower periodicity. We argue that the characteristics of bristle organization are signatures of a Turing-type bifurcation which emerges from a uniform background in reaction-diffusion process, in continua. In contract, fly wing margin consists of a discrete array of cells with possible cross-species interactions. Further, proteins do not diffuse between cells. We argue that the intracellular actions can play the role of diffusion in a discrete cell array. However, the analogs of diffusion coefficients can be positive or negative. Intracellular actions should give a conserved cell number periodicity. We introduce a simple model to study pattern formation in such cellular arrays based on intracellular actions. Also, we observe that periodicity both in length and cell numbers from different group of flies.

  6. Molecular mechanisms for morphogenesis of the central nervous system in mammals.

    PubMed

    Ishibashi, Makoto

    2004-12-01

    The mammalian central nervous system (CNS) is a highly organized structure. In the beginning of CNS development, neural precursor/stem cells are dividing in the neuroepithelium. After a while, these precursors gradually start to differentiate into neurons and glial cells. Various factors are involved in the proliferation and differentiation of neural precursors. Recent studies have demonstrated that the basic helix-loop-helix (bHLH) transcription factors play important roles in differentiation processes. Hairy and Enhancer of split homolog (HES) 1 and HES5 are bHLH-type repressors and inhibit neural differentiation. Mammalian achaete-scute complex homolog (MASH) 1 and mammalian atonal homolog (MATH) 1 are positive bHLH regulators expressed in neural precursors. A balance between positive and negative regulators may determine whether differentiation proceeds or not. The data suggest that this balance is controlled by Notch signaling. Other extracellular signals also govern CNS morphogenesis. To elaborate the primary shape of the CNS, proliferation of neural precursors should be strictly regulated in a spatial and temporal manner. A recent study suggests that a Sonic hedgehog-dependent signaling relay controls growth of the diencephalon and midbrain. Nutrition is another critical factor for development. Expression analysis of Folate binding protein 1 implied the close association between folate uptake and anterior neural tube closure.

  7. Uncovering stem cell differentiation factors for salivary gland regeneration by quantitative analysis of differential proteomes.

    PubMed

    Park, Yun-Jong; Koh, Jin; Kwon, Jin Teak; Park, Yong-Seok; Yang, Lijun; Cha, Seunghee

    2017-01-01

    Severe xerostomia (dry mouth) compromises the quality of life in patients with Sjögren's syndrome or radiation therapy for head and neck cancer. A clinical management of xerostomia is often unsatisfactory as most interventions are palliative with limited efficacy. Following up our previous study demonstrating that mouse BM-MSCs are capable of differentiating into salivary epithelial cells in a co-culture system, we further explored the molecular basis that governs the MSC reprogramming by utilizing high-throughput iTRAQ-2D-LC-MS/MS-based proteomics. Our data revealed the novel induction of pancreas-specific transcription factor 1a (PTF1α), muscle, intestine and stomach expression-1 (MIST-1), and achaete-scute complex homolog 3 (ASCL3) in 7 day co-cultured MSCs but not in control MSCs. More importantly, a common notion of pancreatic-specific expression of PTF1 α was challenged for the first time by our verification of PTF1 α expression in the mouse salivary glands. Furthermore, a molecular network simulation of our selected putative MSC reprogramming factors demonstrated evidence for their perspective roles in salivary gland development. In conclusion, quantitative proteomics with extensive data analyses narrowed down a set of MSC reprograming factors potentially contributing to salivary gland regeneration. Identification of their differential/synergistic impact on MSC conversion warrants further investigation.

  8. Robust specification of sensory neurons by dual functions of charlatan, a Drosophila NRSF/REST-like repressor of extramacrochaetae and hairy.

    PubMed

    Yamasaki, Yasutoyo; Lim, Young-Mi; Niwa, Nao; Hayashi, Shigeo; Tsuda, Leo

    2011-08-01

    Sensory bristle formation in Drosophila is a well-characterized system for studying sensory organ development at the molecular level. The master proneural genes of the achaete-scute (ac-sc) complex, which encode basic-helix-loop-helix (bHLH) transcription factors, are necessary and sufficient for sensory bristle formation. charlatan (chn) was originally identified as a transcriptional activator of ac-sc gene expression through interaction with its enhancer, an activity that promotes sensory bristle development. In contrast, Chn was also identified as a functional homologue of mammalian neuron-restrictive silencing factor or RE1 silencing transcription factor (NRSF/REST), an important transcriptional repressor during vertebrate neurogenesis and stem cell development that acts through epigenetic gene silencing. Here, we report that Chn acts as a repressor of extramacrochaetae (emc) and hairy, molecules that inhibit ac-sc expression. This double-negative mechanism, together with direct activation via the achaete enhancer, increases expression of achaete and ensures robust development of sensory neurons. A mutation in the C-terminal repressor motif of Chn, which causes Chn to lose its repression activity, converted Chn to an activator of emc and hairy, suggesting that Chn is a dual functional regulator of transcription. Because chn-like sequences are found among arthropods, regulation of neuronal development by Chn-like molecules may be widely conserved.

  9. Applicability of Virtual Environments as C4ISR Displays

    DTIC Science & Technology

    2006-06-01

    simulator sickness questionnaire (ssq): A method for quantifying simulator sickness. International Journal of Aviation Psychology, 3(3):203ff. Ergonomie ...Displays Thomas Alexander FGAN - Research Institute for Communication, Information Processing, and Ergonomics Wachtberg, Germany Ergonomie und...Führungssysteme FORSCHUNGSINSTITUT FÜR KOMMUNIKATION, INFORMATIONSVERARBEITUNG UND ERGONOMIE 1 FGAN Applicability of Virtual Environments as C4ISR Displays

  10. Co-delivery of doxorubicin and siRNA using octreotide-conjugated gold nanorods for targeted neuroendocrine cancer therapy

    NASA Astrophysics Data System (ADS)

    Xiao, Yuling; Jaskula-Sztul, Renata; Javadi, Alireza; Xu, Wenjin; Eide, Jacob; Dammalapati, Ajitha; Kunnimalaiyaan, Muthusamy; Chen, Herbert; Gong, Shaoqin

    2012-10-01

    A multifunctional gold (Au) nanorod (NR)-based nanocarrier capable of co-delivering small interfering RNA (siRNA) against achaete-scute complex-like 1 (ASCL1) and an anticancer drug (doxorubicin (DOX)) specifically to neuroendocrine (NE) cancer cells was developed and characterized for combined chemotherapy and siRNA-mediated gene silencing. The Au NR was conjugated with (1) DOX, an anticancer drug, via a pH-labile hydrazone linkage to enable pH-controlled drug release, (2) polyarginine, a cationic polymer for complexing siRNA, and (3) octreotide (OCT), a tumor-targeting ligand, to specifically target NE cancer cells with overexpressed somatostatin receptors. The Au NR-based nanocarriers exhibited a uniform size distribution as well as pH-sensitive drug release. The OCT-conjugated Au NR-based nanocarriers (Au-DOX-OCT, targeted) exhibited a much higher cellular uptake in a human carcinoid cell line (BON cells) than non-targeted Au NR-based nanocarriers (Au-DOX) as measured by both flow cytometry and confocal laser scanning microscopy (CLSM). Moreover, Au-DOX-OCT-ASCL1 siRNA (Au-DOX-OCT complexed with ASCL1 siRNA) resulted in significantly higher gene silencing in NE cancer cells than Au-DOX-ASCL1 siRNA (non-targeted Au-DOX complexed with ASCL1 siRNA) as measured by an immunoblot analysis. Additionally, Au-DOX-OCT-ASCL1 siRNA was the most efficient nanocarrier at altering the NE phenotype of NE cancer cells and showed the strongest anti-proliferative effect. Thus, combined chemotherapy and RNA silencing using NE tumor-targeting Au NR-based nanocarriers could potentially enhance the therapeutic outcomes in treating NE cancers.A multifunctional gold (Au) nanorod (NR)-based nanocarrier capable of co-delivering small interfering RNA (siRNA) against achaete-scute complex-like 1 (ASCL1) and an anticancer drug (doxorubicin (DOX)) specifically to neuroendocrine (NE) cancer cells was developed and characterized for combined chemotherapy and siRNA-mediated gene silencing. The

  11. A theory for the arrangement of sensory organs in Drosophila

    NASA Astrophysics Data System (ADS)

    Zhu, Huifeng; Gunaratne, Preethi H.; Roman, Gregg W.; Gunaratne, Gemunu H.

    2010-03-01

    We study the arrangements of recurved bristles on the anterior wing margin of wild-type and mutant Drosophila. The epidermal or neural fate of a proneural cell depends on the concentrations of proteins of the achaete-scute complex. At puparium formation, concentrations of proteins are nearly identical in all cells of the anterior wing and each cell has the potential for neural fate. In wild-type flies, the action of regulatory networks drives the initial state to one where a bristle grows out of every fifth cell. Recent experiments have shown that the frequency of recurved bristles can be made to change by adjusting the mean concentrations of the zinc-finger transcription factor Senseless and the micro-RNA miR-9a. Specifically, mutant flies with reduced levels of miR-9a exhibit ectopic bristles, and those with lower levels of both miR-9a and Senseless show regular organization of recurved bristles, but with a lower periodicity of 4. We argue that these characteristics can be explained assuming an underlying Turing-type bifurcation whereby a periodic pattern spontaneously emerges from a uniform background. However, bristle patterns occur in a discrete array of cells, and are not mediated by diffusion. We argue that intracellular actions of transmembrane proteins such as Delta and Notch can play a role of diffusion in destabilizing the homogeneous state. In contrast to diffusion, intercellular actions can be activating or inhibiting; further, there can be lateral cross-species interactions. We introduce a phenomenological model to study bristle arrangements and make several model-independent predictions that can be tested in experiments. In our theory, miRNA-9a is one of the components of the underlying network and has no special regulatory role. The loss of periodicity in its absence is due to the transfer of the system to a bistable state.

  12. Increased dosage of the imprinted Ascl2 gene restrains two key endocrine lineages of the mouse Placenta.

    PubMed

    Tunster, S J; McNamara, G I; Creeth, H D J; John, R M

    2016-10-01

    Imprinted genes are expressed primarily from one parental allele by virtue of a germ line epigenetic process. Achaete-scute complex homolog 2 (Ascl2 aka Mash2) is a maternally expressed imprinted gene that plays a key role in placental and intestinal development. Loss-of-function of Ascl2 results in an expansion of the parietal trophoblast giant cell (P-TGC) lineage, an almost complete loss of Trophoblast specific protein alpha (Tpbpa) positive cells in the ectoplacental cone and embryonic failure by E10.5. Tpbpa expression marks the progenitors of some P-TGCs, two additional trophoblast giant cell lineages (spiral artery and canal), the spongiotrophoblast and the glycogen cell lineage. Using a transgenic model, here we show that elevated expression of Ascl2 reduced the number of P-TGC cells by 40%. Elevated Ascl2 also resulted in a marked loss of the spongiotrophoblast and a substantial mislocalisation of glycogen cells into the labyrinth. In addition, Ascl2-Tg placenta contained considerably more placental glycogen than wild type. Glycogen cells are normally located within the junctional zone in close contact with spongiotrophoblast cells, before migrating through the P-TGC layer into the maternal decidua late in gestation where their stores of glycogen are released. The failure of glycogen cells to release their stores of glycogen may explain both the inappropriate accumulation of glycogen and fetal growth restriction observed late in gestation in this model. In addition, using in a genetic cross we provide evidence that Ascl2 requires the activity of a second maternally expressed imprinted gene, Pleckstrin homology-like domain, family a, member 2 (Phlda2) to limit the expansion of the spongiotrophoblast. This "belts and braces" approach demonstrates the importance of genomic imprinting in regulating the size of the placental endocrine compartment for optimal placental development and fetal growth. Copyright © 2016 The Authors. Published by Elsevier Inc. All

  13. Inhibition of the PI3K Pathway Suppresses Hormonal Secretion and Limits Growth in Pheochromocytoma Cells

    PubMed Central

    Adler, Joel T.; Hottinger, Daniel G.

    2009-01-01

    Background Operative resection is the only curative treatment for pheochromocytomas. Inhibition of the phosphatidylinositol-3 kinase (PI3K)-Akt pathway has been shown to be an effective treatment of neuroendocrine (NE) tumors in vitro. We hypothesized that inhibition of the PI3K-Akt pathway would be a viable strategy to inhibit growth and hormonal secretion in pheochromocytoma cells. Methods Sixteen pheochromocytomas were analyzed for expression of phosphorylated Akt and the NE marker achaete scute complex-like 1 (ASCL1). Pheochromocytoma PC-12 cells were treated with up to 100 µM of the PI3K-specific inhibitor LY294002 for 48 h. Western blot analysis was used to measure phosphorylated Akt, total Akt, ASCL1, chromogranin A (CgA), and markers of apoptosis. Growth was assessed by a methylthiazolyldiphenyl-tetrazolium (MTT) bromide cellular proliferation assay for six days. Results Human pheochromocytomas expressed significant amounts of phosphorylated Akt, and there was a significant correlation between malignant pheochromocytomas and the amount of expressed ASCL1. LY294002 significantly inhibited the PI3K-Akt pathway. Treatment led to a dose-dependent decrease in both ASCL1 and CgA, indicating an alteration in the NE phenotype and hormonal suppression. Treatment decreased cellular proliferation, and cleavage of the apoptotic markers caspase-3 and PARP was observed. Conclusions Human pheochromocytoma tumor samples express high levels of phosphorylated Akt. LY294002 effectively inhibits the PI3K-Akt pathway, suppresses NE tumor markers, and decreases cellular proliferation via apoptosis in vitro. Inhibition of the PI3K pathway may represent a new strategy in the treatment of pheochromocytomas. PMID:19669229

  14. Cell cycle and lineage progression of neural progenitors in the ventricular-subventricular zones of adult mice

    PubMed Central

    Ponti, Giovanna; Obernier, Kirsten; Guinto, Cristina; Jose, Lingu; Bonfanti, Luca; Alvarez-Buylla, Arturo

    2013-01-01

    Proliferating neural stem cells and intermediate progenitors persist in the ventricular-subventricular zone (V-SVZ) of the adult mammalian brain. This extensive germinal layer in the walls of the lateral ventricles is the site of birth of different types of interneurons destined for the olfactory bulb. The cell cycle dynamics of stem cells (B1 cells), intermediate progenitors (C cells), and neuroblasts (A cells) in the V-SVZ and the number of times these cells divide remain unknown. Using whole mounts of the walls of the lateral ventricles of adult mice and three cell cycle analysis methods using thymidine analogs, we determined the proliferation dynamics of B1, C, and A cells in vivo. Achaete-scute complex homolog (Ascl)1+ C cells were heterogeneous with a cell cycle length (TC) of 18–25 h and a long S phase length (TS) of 14–17 h. After C cells, Doublecortin+ A cells were the second-most common dividing cell type in the V-SVZ and had a TC of 18 h and TS of 9 h. Human glial fibrillary acidic protein (hGFAP)::GFP+ B1 cells had a surprisingly short Tc of 17–18 h and a TS of 4 h. Progenitor population analysis suggests that following the initial division of B1 cells, C cells divide three times and A cells once, possibly twice. These data provide essential information on the dynamics of adult progenitor cell proliferation in the V-SVZ and how large numbers of new neurons continue to be produced in the adult mammalian brain. PMID:23431204

  15. Tumor necrosis factor-alpha is produced by dying retinal neurons and is required for Müller glia proliferation during zebrafish retinal regeneration

    PubMed Central

    Nelson, Craig M.; Ackerman, Kristin M.; O’Hayer, Patrick; Bailey, Travis J.; Gorsuch, Ryne A.; Hyde, David R.

    2013-01-01

    Intense light exposure causes photoreceptor apoptosis in dark-adapted adult albino zebrafish (Danio rerio). Subsequently, Müller glia increase expression of the Achaete-scute complex-like 1a (Ascl1a) and Signal transducer and activator of transcription 3(Stat3) transcription factors and reenter the cell cycle to yield undifferentiated neuronal progenitors that continue to proliferate, migrate to the outer nuclear layer, and differentiate into photoreceptors. A proteomic analysis of light-damaged retinal homogenates, which induced Müller glia proliferation when injected into an undamaged eye, revealed increased expression of Tumor necrosis factor α (TNFα) signaling proteins relative to undamaged retinal homogenates. TNFα expression initially increased in apoptotic photoreceptors and later in Müller glia. Morpholino-mediated knockdown of TNFα expression prior to light damage diminished the expression of both Ascl1a and Stat3 in Müller glia and significantly reduced the number of proliferating Müller glia without affecting photoreceptor cell death. Knockdown of TNFα expression in the Müller glia resulted in fewer proliferating Müller glia, suggesting that Müller glial-derived TNFα recruited additional Müller glia to reenter the cell cycle. While TNFα is required for increased Ascl1a and Stat3 expression, Ascl1a and Stat3 are both necessary for TNFα expression in Müller glia. Apoptotic inner retinal neurons, resulting from intravitreal injection of ouabain, also exhibited increased TNFα expression that was required for Müller glia proliferation. Thus, TNFα is the first molecule identified that is produced by dying retinal neurons and is necessary to induce Müller glia to proliferate in the zebrafish retinal regeneration response. PMID:23575850

  16. Tumor necrosis factor-alpha is produced by dying retinal neurons and is required for Muller glia proliferation during zebrafish retinal regeneration.

    PubMed

    Nelson, Craig M; Ackerman, Kristin M; O'Hayer, Patrick; Bailey, Travis J; Gorsuch, Ryne A; Hyde, David R

    2013-04-10

    Intense light exposure causes photoreceptor apoptosis in dark-adapted adult albino zebrafish (Danio rerio). Subsequently, Müller glia increase expression of the Achaete-scute complex-like 1a (Ascl1a) and Signal transducer and activator of transcription 3 (Stat3) transcription factors and re-enter the cell cycle to yield undifferentiated neuronal progenitors that continue to proliferate, migrate to the outer nuclear layer, and differentiate into photoreceptors. A proteomic analysis of light-damaged retinal homogenates, which induced Müller glia proliferation when injected into an undamaged eye, revealed increased expression of tumor necrosis factor α (TNFα) signaling proteins relative to undamaged retinal homogenates. TNFα expression initially increased in apoptotic photoreceptors and later in Müller glia. Morpholino-mediated knockdown of TNFα expression before light damage diminished the expression of both Ascl1a and Stat3 in Müller glia and significantly reduced the number of proliferating Müller glia without affecting photoreceptor cell death. Knockdown of TNFα expression in the Müller glia resulted in fewer proliferating Müller glia, suggesting that Müller glial-derived TNFα recruited additional Müller glia to re-enter the cell cycle. While TNFα is required for increased Ascl1a and Stat3 expression, Ascl1a and Stat3 are both necessary for TNFα expression in Müller glia. Apoptotic inner retinal neurons, resulting from intravitreal injection of ouabain, also exhibited increased TNFα expression that was required for Müller glia proliferation. Thus, TNFα is the first molecule identified that is produced by dying retinal neurons and is necessary to induce Müller glia to proliferate in the zebrafish retinal regeneration response.

  17. UTSW Researchers Identify Potential Therapeutic Targets for High-grade Neuroendocrine Lung Cancers | Office of Cancer Genomics

    Cancer.gov

    Neuroendocrine specific lung cancers comprise about 10% of non-small cell lung cancer (NSCLC) cases and all small cell lung cancer (SCLC) cases. Studies have previously shown that the transcription factor achaete-scute homolog 1 (ASCL1) is a cancer “lineage” factor required for the development and survival of SCLC, and is highly expressed in neuroendocrine-specific NSCLC (NE-NSCLC).

  18. Discovery of pyrazole as C-terminus of selective BACE1 inhibitors.

    PubMed

    Zou, Yiquan; Xu, Lei; Chen, Wuyan; Zhu, Yiping; Chen, Tiantian; Fu, Yan; Li, Li; Ma, Lanping; Xiong, Bing; Wang, Xin; Li, Jian; He, Jianhua; Zhang, Haiyan; Xu, Yechun; Li, Jia; Shen, Jingkang

    2013-10-01

    We recently discovered and reported dual inhibitor 5 of AChE and BACE1 with N-benzylpiperidine ethyl as C-terminus. Compound 5 showed potent inhibitory activities for BACE1, and could reduce endogenous Aβ1-40 production in APP transgenic mice. In present work, we rapidly identified substituted triazole as the C-terminus of compound 5 by replacing the benzylpiperidine ethyl group with click chemistry and tested these synthesized compounds by in situ screening assay. As revealed by the crystal structures of BACE1 in complex with our triazole compound 12, we found that Pro70 and Thr72 located in the flap region were the critical components for binding with these inhibitors. With the aid of the crystal structure, a new series of five-membered heterocyclic compounds was prepared in order to explore the structure-activity relationship (SAR) of this class of molecules. From these efforts, pyrazole was discovered as a novel C-terminus of BACE1 inhibitors. After further modification of pyrazole with variable substituents, compound 37 exhibited good potency in enzyme inhibition assay (IC50=0.025 μM) and compound 33 showed moderate inhibition effects on Aβ production of APP transfected HEK293 cells. Moreover, these pyrazole derivatives demonstrated good selectivity versus cathepsin D. Our results indicated that the vicinity of Pro70 and Thr72 might be utilized as a subsite, and the discovered pyrazole derivatives might provide useful hints for developing novel BACE1 inhibitors as anti-AD drugs.

  19. The role of hypoxia and neurogenic genes (Mash-1 and Prox-1) in the developmental programming and maturation of pulmonary neuroendocrine cells in fetal mouse lung.

    PubMed

    McGovern, Suzanne; Pan, Jie; Oliver, Guillermo; Cutz, Ernest; Yeger, Herman

    2010-02-01

    Pulmonary neuroendocrine cells (PNECs) are the first cell type to differentiate within the primitive airway epithelium, suggesting a possible role in lung development. The differentiation of PNECs in fetal lung is governed by proneural genes such as the mammalian homolog of the achaete-scute complex (Mash-1) and a related transcription factor, hairy and enhancer of split1 (Hes-1). We examined the expression of Mash-1 and a downstream transcription factor Prox-1 in the developing mouse lung of wild-type and respective knockout mouse models. During early stages (embryonic day 12, E12) of development, only some PNECs expressed Mash-1 and Prox-1, but by E15, all PNECs coexpressed both transcription factors. PNECs failed to develop in Mash-1 but not in Prox-1-null mice, indicating that Mash-1 is essential for the initiation of the PNEC phenotype, whereas Prox-1 is associated with the development of this phenotype. As lung develops within a low O(2) environment (fetal euoxia, pO(2) approximately 20 to 30 mm Hg), we examined the effects of hypoxia on PNEC differentiation. Organ cultures of fetal mouse lungs at E12 and E16 were maintained under either 20% O(2) (normoxia, Nox) or 5% O(2) (hypoxia, Hox) and were examined every 24 h for up to 6 days in culture. In E12 explants, Hox enhanced branching morphogenesis and increased cell proliferation, but PNEC numbers and Mash-1 expression were significantly reduced. This effect could be reversed by switching the explants back to Nox. In contrast, Hox had no apparent effect on Hes-1 expression. Similarly, Hox had no effect on airway branching, PNEC numbers, or Mash-1 expression in E16 explants, indicating locked-in developmental programming. We suggest that during early stages of lung development, pO(2) concentration in concert with neurogenic gene expression modulates PNEC phenotype. Thus, disturbances in intrauterine pO(2) homeostasis could alter the functional maturation of the PNEC system and hence be involved in the

  20. miR-124-9-9* potentiates Ascl1-induced reprogramming of cultured Müller glia.

    PubMed

    Wohl, Stefanie Gabriele; Reh, Thomas Andrew

    2016-05-01

    The Müller glia of fish provide a source for neuronal regeneration after injury, but they do not do so in mammals. We previously showed that lentiviral gene transfer of the transcription factor Achaete-scute homolog 1 (Ascl1/Mash1) in murine Müller glia cultures resulted in partial reprogramming of the cells to retinal progenitors. The microRNAs (miRNAs) miR-124-9-9* facilitate neuronal reprogramming of fibroblasts, but their role in glia reprogramming has not been reported. The aim of this study was to test whether (1) lentiviral gene transfer of miR-124-9-9* can reprogram Müller glia into retinal neurons and (2) miR-124-9-9* can improve Ascl1-induced reprogramming. Primary Müller glia cultures were generated from postnatal day (P) 11/12 mice, transduced with lentiviral particles, i.e., miR-124-9-9*-RFP, nonsense-RFP, Ascl1-GFP, or GFP-control. Gene expression and immunofluorescence analyses were performed within 3 weeks after infection. 1. Overexpression of miR-124-9-9* induced the expression of the proneural factor Ascl1 and additional markers of neurons, including TUJ1 and MAP2. 2. When Ascl1 and miR-124-9-9* were combined, 50 to 60% of Müller glia underwent neuronal reprogramming, whereas Ascl1 alone results in a 30 to 35% reprogramming rate. 3. Analysis of the miR-124-9-9* treated glial cells showed a reduction in the level of Ctdsp1 and Ptbp1, indicating a critical role for the REST pathway in the repression of neuronal genes in Müller glia. Our data further suggest that miR-124-9-9* and the REST complex may play a role in regulating the reprogramming of Müller glia to progenitors that underlies retinal regeneration in zebrafish.

  1. Transition Metal-Catalyzed Utilization of Methanol as C1 Source in Organic Synthesis.

    PubMed

    Rajenahally, Jagadeesh; Natte, Kishore; Neumann, Helfried; Beller, Matthias

    2017-03-09

    Methanol represents one of the privileged and widespread platform chemicals, which is used in many science sectors such as chemistry, biology, medicine and energy. This essential alcohol serves as common solvent, cost-effective reagent and sustainable feedstock for value-added chemicals, pharmaceuticals and materials. Among different applications, the utilization of methanol as C1 source for the formation of carbon-carbon, carbon-nitrogen and carbon-oxygen bonds continues to be important in organic synthesis and drug discovery. Particularly, the synthesis of C-methylated, N-methylated and O-methylated products is of central interest because these motifs are found in a large number of life science molecules as well as fine and bulk chemicals. In this Minireview, we summarize the utilization of methanol as C1 source in C-methylation, N-methylation, C-methoxylation, N-formylation, methoxycarbonylation and oxidative methyl esterification reactions for the synthesis of C-methylated products, N-methylamines, formamides, urea derivatives, ethers, esters and heterocycles.

  2. p-Ohmic contact resistance for GaAs(C)/GaN(Mg)

    NASA Astrophysics Data System (ADS)

    Dang, G. T.; Zhang, A. P.; Ren, F.; Donovan, S. M.; Abernathy, C. R.; Hobson, W. S.; Lopata, J.; Chu, S. N. G.; Cao, X. A.; Wilson, R. G.; Pearton, S. J.

    2000-01-01

    Heavily carbon-doped (p≥10 10 cm -3) GaAs layers were grown on p-GaN in attempt to reduce the p-ohmic contact resistance. While the specific contact resistances on the p-GaN and p-GaAs were typical of the current state-of-the-art (˜10 -3 and 10 -5 Ω cm 3, respectively), the high valence band offset at the GaAs/GaN interface produced a barrier to hole transport. The specific contact resistance for the GaAs(C)/GaN(Mg) structure was better than that of GaN alone, but was still in the 10 -3 Ω cm 2 range, even after alloying of the metal at 800°C. Other approaches to lowering contact resistance on p-GaN are discussed.

  3. Complexity Survey.

    ERIC Educational Resources Information Center

    Gordon, Sandra L.; Anderson, Beth C.

    To determine whether consensus existed among teachers about the complexity of common classroom materials, a survey was administered to 66 pre-service and in-service kindergarten and prekindergarten teachers. Participants were asked to rate 14 common classroom materials as simple, complex, or super-complex. Simple materials have one obvious part,…

  4. Complexity Survey.

    ERIC Educational Resources Information Center

    Gordon, Sandra L.; Anderson, Beth C.

    To determine whether consensus existed among teachers about the complexity of common classroom materials, a survey was administered to 66 pre-service and in-service kindergarten and prekindergarten teachers. Participants were asked to rate 14 common classroom materials as simple, complex, or super-complex. Simple materials have one obvious part,…

  5. Communication complexity and information complexity

    NASA Astrophysics Data System (ADS)

    Pankratov, Denis

    Information complexity enables the use of information-theoretic tools in communication complexity theory. Prior to the results presented in this thesis, information complexity was mainly used for proving lower bounds and direct-sum theorems in the setting of communication complexity. We present three results that demonstrate new connections between information complexity and communication complexity. In the first contribution we thoroughly study the information complexity of the smallest nontrivial two-party function: the AND function. While computing the communication complexity of AND is trivial, computing its exact information complexity presents a major technical challenge. In overcoming this challenge, we reveal that information complexity gives rise to rich geometrical structures. Our analysis of information complexity relies on new analytic techniques and new characterizations of communication protocols. We also uncover a connection of information complexity to the theory of elliptic partial differential equations. Once we compute the exact information complexity of AND, we can compute exact communication complexity of several related functions on n-bit inputs with some additional technical work. Previous combinatorial and algebraic techniques could only prove bounds of the form theta( n). Interestingly, this level of precision is typical in the area of information theory, so our result demonstrates that this meta-property of precise bounds carries over to information complexity and in certain cases even to communication complexity. Our result does not only strengthen the lower bound on communication complexity of disjointness by making it more exact, but it also shows that information complexity provides the exact upper bound on communication complexity. In fact, this result is more general and applies to a whole class of communication problems. In the second contribution, we use self-reduction methods to prove strong lower bounds on the information

  6. Complex odontoma.

    PubMed

    Preetha, A; Balikai, Bharati S; Sujatha, D; Pai, Anuradha; Ganapathy, K S

    2010-01-01

    Odontomas are hamartomatous lesions or malformations composed of mature enamel, dentin, and pulp. They may be compound or complex, depending on the extent of morphodifferentiation or their resemblance to normal teeth. The etiology of odontoma is unknown, although several theories have been proposed. This article describes a case of a large infected complex odontoma in the residual mandibular ridge, resulting in considerable mandibular expansion.

  7. Designing Complexity

    ERIC Educational Resources Information Center

    Glanville, Ranulph

    2007-01-01

    This article considers the nature of complexity and design, as well as relationships between the two, and suggests that design may have much potential as an approach to improving human performance in situations seen as complex. It is developed against two backgrounds. The first is a world view that derives from second order cybernetics and radical…

  8. Complex derivatives

    NASA Astrophysics Data System (ADS)

    Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph

    2013-03-01

    The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.

  9. Complex Clouds

    Atmospheric Science Data Center

    2013-04-16

    ...     View Larger Image The complex structure and beauty of polar clouds are highlighted by these images acquired ... MD. The MISR data were obtained from the NASA Langley Research Center Atmospheric Science Data Center in Hampton, VA. Image ...

  10. Softball Complex

    ERIC Educational Resources Information Center

    Ellis, Jim

    1977-01-01

    The Parks and Recreation Department of Montgomery, Alabama, has developed a five-field softball complex as part of a growing community park with facilities for camping, golf, aquatics, tennis, and picnicking. (MJB)

  11. Complex chimerism

    PubMed Central

    Ma, Kimberly K.; Petroff, Margaret G.; Coscia, Lisa A.; Armenti, Vincent T.; Adams Waldorf, Kristina M.

    2013-01-01

    Thousands of women with organ transplantation have undergone successful pregnancies, however little is known about how the profound immunologic changes associated with pregnancy might influence tolerance or rejection of the allograft. Pregnant women with a solid organ transplant are complex chimeras with multiple foreign cell populations from the donor organ, fetus, and mother of the pregnant woman. We consider the impact of complex chimerism and pregnancy-associated immunologic changes on tolerance of the allograft both during pregnancy and the postpartum period. Mechanisms of allograft tolerance are likely dynamic during pregnancy and affected by the influx of fetal microchimeric cells, HLA relationships (between the fetus, pregnant woman and/or donor), peripheral T cell tolerance to fetal cells, and fetal minor histocompatibility antigens. Further research is necessary to understand the complex immunology during pregnancy and the postpartum period of women with a solid organ transplant. PMID:23974274

  12. Complex interactions

    NASA Astrophysics Data System (ADS)

    de Régules, Sergio

    2016-04-01

    Complexity science - which describes phenomena such as collective and emergent behaviour - is the focus of a new centre where researchers are examining everything from the spread of influenza to what a healthy heartbeat looks like. Sergio de Régules reports.

  13. Amorphic complexity

    NASA Astrophysics Data System (ADS)

    Fuhrmann, G.; Gröger, M.; Jäger, T.

    2016-02-01

    We introduce amorphic complexity as a new topological invariant that measures the complexity of dynamical systems in the regime of zero entropy. Its main purpose is to detect the very onset of disorder in the asymptotic behaviour. For instance, it gives positive value to Denjoy examples on the circle and Sturmian subshifts, while being zero for all isometries and Morse-Smale systems. After discussing basic properties and examples, we show that amorphic complexity and the underlying asymptotic separation numbers can be used to distinguish almost automorphic minimal systems from equicontinuous ones. For symbolic systems, amorphic complexity equals the box dimension of the associated Besicovitch space. In this context, we concentrate on regular Toeplitz flows and give a detailed description of the relation to the scaling behaviour of the densities of the p-skeletons. Finally, we take a look at strange non-chaotic attractors appearing in so-called pinched skew product systems. Continuous-time systems, more general group actions and the application to cut and project quasicrystals will be treated in subsequent work.

  14. Researching Complexity.

    ERIC Educational Resources Information Center

    Sumara, Dennis J.

    2000-01-01

    Discusses what Complexity Theory (presented as a rubric that collects theoretical understandings from a number of domains such as ecology, biology, neurology, and education) suggests about mind, selfhood, intelligence, and practices of reading, and the import of these reconceptualizations to reader-response researchers. Concludes that developing…

  15. Researching Complexity.

    ERIC Educational Resources Information Center

    Sumara, Dennis J.

    2000-01-01

    Discusses what Complexity Theory (presented as a rubric that collects theoretical understandings from a number of domains such as ecology, biology, neurology, and education) suggests about mind, selfhood, intelligence, and practices of reading, and the import of these reconceptualizations to reader-response researchers. Concludes that developing…

  16. Complex chemistry with complex compounds

    NASA Astrophysics Data System (ADS)

    Eichler, Robert; Asai, M.; Brand, H.; Chiera, N. M.; Di Nitto, A.; Dressler, R.; Düllmann, Ch. E.; Even, J.; Fangli, F.; Goetz, M.; Haba, H.; Hartmann, W.; Jäger, E.; Kaji, D.; Kanaya, J.; Kaneya, Y.; Khuyagbaatar, J.; Kindler, B.; Komori, Y.; Kraus, B.; Kratz, J. V.; Krier, J.; Kudou, Y.; Kurz, N.; Miyashita, S.; Morimoto, K.; Morita, K.; Murakami, M.; Nagame, Y.; Ooe, K.; Piguet, D.; Sato, N.; Sato, T. K.; Steiner, J.; Steinegger, P.; Sumita, T.; Takeyama, M.; Tanaka, K.; Tomitsuka, T.; Toyoshima, A.; Tsukada, K.; Türler, A.; Usoltsev, I.; Wakabayashi, Y.; Wang, Y.; Wiehl, N.; Wittwer, Y.; Yakushev, A.; Yamaki, S.; Yano, S.; Yamaki, S.; Qin, Z.

    2016-12-01

    In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the investigation of fragile single molecular species by gas-phase chromatography. The latest success with the heaviest group 6 transactinide seaborgium is highlighted. The formation of a very volatile hexacarbonyl compound Sg(CO)6 was observed similarly to its lighter homologues molybdenum and tungsten. The interactions of these gaseous carbonyl complex compounds with quartz surfaces were investigated by thermochromatography. Second-generation experiments are under way to investigate the intramolecular bond between the central metal atom of the complexes and the ligands addressing the influence of relativistic effects in the heaviest compounds. Our contribution comprises some aspects of the ongoing challenging experiments as well as an outlook towards other interesting compounds related to volatile complex compounds in the gas phase.

  17. Complex Questions Promote Complex Thinking

    ERIC Educational Resources Information Center

    Degener, Sophie; Berne, Jennifer

    2017-01-01

    Intermediate-grade teachers often express concerns about meeting the Common Core State Standards for Reading, primarily because of the emphasis on deep understanding of complex texts. No matter how difficult the text, if teachers demand little of the reading, student meaning making is not challenged. This article offers a tool for teachers to…

  18. Managing Complexity

    SciTech Connect

    Chassin, David P.; Posse, Christian; Malard, Joel M.

    2004-08-01

    Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today’s most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically-based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This paper explores the state of the art in the use physical analogs for understanding the behavior of some econophysical systems and to deriving stable and robust control strategies for them. In particular we review and discussion applications of some analytic methods based on the thermodynamic metaphor according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood.

  19. Complex Systems

    PubMed Central

    Goldberger, Ary L.

    2006-01-01

    Physiologic systems in health and disease display an extraordinary range of temporal behaviors and structural patterns that defy understanding based on linear constructs, reductionist strategies, and classical homeostasis. Application of concepts and computational tools derived from the contemporary study of complex systems, including nonlinear dynamics, fractals and “chaos theory,” is having an increasing impact on biology and medicine. This presentation provides a brief overview of an emerging area of biomedical research, including recent applications to cardiopulmonary medicine and chronic obstructive lung disease. PMID:16921107

  20. ASCL1 Reorganizes Chromatin to Direct Neuronal Fate and Suppress Tumorigenicity of Glioblastoma Stem Cells.

    PubMed

    Park, Nicole I; Guilhamon, Paul; Desai, Kinjal; McAdam, Rochelle F; Langille, Ellen; O'Connor, Madlen; Lan, Xiaoyang; Whetstone, Heather; Coutinho, Fiona J; Vanner, Robert J; Ling, Erick; Prinos, Panagiotis; Lee, Lilian; Selvadurai, Hayden; Atwal, Gurnit; Kushida, Michelle; Clarke, Ian D; Voisin, Veronique; Cusimano, Michael D; Bernstein, Mark; Das, Sunit; Bader, Gary; Arrowsmith, Cheryl H; Angers, Stephane; Huang, Xi; Lupien, Mathieu; Dirks, Peter B

    2017-08-03

    Glioblastomas exhibit a hierarchical cellular organization, suggesting that they are driven by neoplastic stem cells that retain partial yet abnormal differentiation potential. Here, we show that a large subset of patient-derived glioblastoma stem cells (GSCs) express high levels of Achaete-scute homolog 1 (ASCL1), a proneural transcription factor involved in normal neurogenesis. ASCL1(hi) GSCs exhibit a latent capacity for terminal neuronal differentiation in response to inhibition of Notch signaling, whereas ASCL1(lo) GSCs do not. Increasing ASCL1 levels in ASCL1(lo) GSCs restores neuronal lineage potential, promotes terminal differentiation, and attenuates tumorigenicity. ASCL1 mediates these effects by functioning as a pioneer factor at closed chromatin, opening new sites to activate a neurogenic gene expression program. Directing GSCs toward terminal differentiation may provide therapeutic applications for a subset of GBM patients and strongly supports efforts to restore differentiation potential in GBM and other cancers. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Intraoperative hypertensive crisis due to a catecholamine-secreting esthesioneuroblastoma

    PubMed Central

    Salmasi, Vafi; Schiavi, Adam; Binder, Zev A.; Ruzevick, Jacob; Orr, Brent A.; Burger, Peter C.; Ball, Douglas W.; Blitz, Ari M.; Koch, Wayne M.; Ishii, Masaru; Gallia, Gary L.

    2015-01-01

    Background Although uncommon, esthesioneuroblastomas may produce clinically significant amounts of catecholamines. Methods We report a patient with a catecholamine-secreting esthesioneuroblastoma who developed intraoperative hypertensive crisis. Results A patient with history of hypertension was referred to our skull base center for management of a residual esthesioneuroblastoma. A staged endonasal endoscopic approach was planned. At the conclusion of the first stage, a hypertensive crisis occurred. Work-up revealed elevated levels of serum and urinary catecholamines. The patient was treated with alpha adrenoceptor blockade prior to the second stage. Serum catecholamine levels following this second stage were normal. On immunohistochemical analysis, the tumor cells were found to be positive for tyrosine hydroxylase, the rate limiting enzyme in cathecholamine synthesis, and achaete-scute homologue 1, a transcription factor essential in the development of olfactory and sympathetic neurons. Conclusion Catecholamine production should be considered in the differential of unexpected extreme hypertension during surgical resection of esthesioneuroblastoma. PMID:25352487

  2. Return to quiescence of murine neural stem cells by degradation of a pro-activation protein

    PubMed Central

    Urbán, Noelia; van den Berg, Debbie L.C.; Forget, Antoine; Andersen, Jimena; Demmers, Jeroen A.; Hunt, Charles; Ayrault, Olivier; Guillemot, François

    2017-01-01

    Quiescence is essential for long-term maintenance of adult stem cells. Niche signals regulate the transit of stem cells from dormant to activated states. Here we show that the E3-ubiquitin ligase Huwe1 (HECT, UBA and WWE domain containing 1) is required for proliferating stem cells of the adult mouse hippocampus to return to quiescence. Huwe1 destabilises pro-activation protein Ascl1 (achaete-scute family bHLH transcription factor 1) in proliferating hippocampal stem cells, which prevents accumulation of cyclin Ds and promotes the return to a resting state. When stem cells fail to return to quiescence, the proliferative stem cell pool becomes depleted. Thus, long-term maintenance of hippocampal neurogenesis depends on the return of stem cells to a transient quiescent state through the rapid degradation of a key activation factor. PMID:27418510

  3. Cosmic Complexity

    NASA Technical Reports Server (NTRS)

    Mather, John C.

    2012-01-01

    What explains the extraordinary complexity of the observed universe, on all scales from quarks to the accelerating universe? My favorite explanation (which I certainty did not invent) ls that the fundamental laws of physics produce natural instability, energy flows, and chaos. Some call the result the Life Force, some note that the Earth is a living system itself (Gaia, a "tough bitch" according to Margulis), and some conclude that the observed complexity requires a supernatural explanation (of which we have many). But my dad was a statistician (of dairy cows) and he told me about cells and genes and evolution and chance when I was very small. So a scientist must look for me explanation of how nature's laws and statistics brought us into conscious existence. And how is that seemll"!gly Improbable events are actually happening a!1 the time? Well, the physicists have countless examples of natural instability, in which energy is released to power change from simplicity to complexity. One of the most common to see is that cooling water vapor below the freezing point produces snowflakes, no two alike, and all complex and beautiful. We see it often so we are not amazed. But physlc!sts have observed so many kinds of these changes from one structure to another (we call them phase transitions) that the Nobel Prize in 1992 could be awarded for understanding the mathematics of their common features. Now for a few examples of how the laws of nature produce the instabilities that lead to our own existence. First, the Big Bang (what an insufficient name!) apparently came from an instability, in which the "false vacuum" eventually decayed into the ordinary vacuum we have today, plus the most fundamental particles we know, the quarks and leptons. So the universe as a whole started with an instability. Then, a great expansion and cooling happened, and the loose quarks, finding themselves unstable too, bound themselves together into today's less elementary particles like protons and

  4. Cosmic Complexity

    NASA Technical Reports Server (NTRS)

    Mather, John C.

    2012-01-01

    What explains the extraordinary complexity of the observed universe, on all scales from quarks to the accelerating universe? My favorite explanation (which I certainty did not invent) ls that the fundamental laws of physics produce natural instability, energy flows, and chaos. Some call the result the Life Force, some note that the Earth is a living system itself (Gaia, a "tough bitch" according to Margulis), and some conclude that the observed complexity requires a supernatural explanation (of which we have many). But my dad was a statistician (of dairy cows) and he told me about cells and genes and evolution and chance when I was very small. So a scientist must look for me explanation of how nature's laws and statistics brought us into conscious existence. And how is that seemll"!gly Improbable events are actually happening a!1 the time? Well, the physicists have countless examples of natural instability, in which energy is released to power change from simplicity to complexity. One of the most common to see is that cooling water vapor below the freezing point produces snowflakes, no two alike, and all complex and beautiful. We see it often so we are not amazed. But physlc!sts have observed so many kinds of these changes from one structure to another (we call them phase transitions) that the Nobel Prize in 1992 could be awarded for understanding the mathematics of their common features. Now for a few examples of how the laws of nature produce the instabilities that lead to our own existence. First, the Big Bang (what an insufficient name!) apparently came from an instability, in which the "false vacuum" eventually decayed into the ordinary vacuum we have today, plus the most fundamental particles we know, the quarks and leptons. So the universe as a whole started with an instability. Then, a great expansion and cooling happened, and the loose quarks, finding themselves unstable too, bound themselves together into today's less elementary particles like protons and

  5. Cosmic Complexity

    NASA Technical Reports Server (NTRS)

    Mather, John C.

    2012-01-01

    What explains the extraordinary complexity of the observed universe, on all scales from quarks to the accelerating universe? My favorite explanation (which I certainty did not invent) ls that the fundamental laws of physics produce natural instability, energy flows, and chaos. Some call the result the Life Force, some note that the Earth is a living system itself (Gaia, a "tough bitch" according to Margulis), and some conclude that the observed complexity requires a supernatural explanation (of which we have many). But my dad was a statistician (of dairy cows) and he told me about cells and genes and evolution and chance when I was very small. So a scientist must look for me explanation of how nature's laws and statistics brought us into conscious existence. And how is that seemll"!gly Improbable events are actually happening a!1 the time? Well, the physicists have countless examples of natural instability, in which energy is released to power change from simplicity to complexity. One of the most common to see is that cooling water vapor below the freezing point produces snowflakes, no two alike, and all complex and beautiful. We see it often so we are not amazed. But physlc!sts have observed so many kinds of these changes from one structure to another (we call them phase transitions) that the Nobel Prize in 1992 could be awarded for understanding the mathematics of their common features. Now for a few examples of how the laws of nature produce the instabilities that lead to our own existence. First, the Big Bang (what an insufficient name!) apparently came from an instability, in which the "false vacuum" eventually decayed into the ordinary vacuum we have today, plus the most fundamental particles we know, the quarks and leptons. So the universe as a whole started with an instability. Then, a great expansion and cooling happened, and the loose quarks, finding themselves unstable too, bound themselves together into today's less elementary particles like protons and

  6. Atomic and electronic structure of single-walled BN nanotubes containing N vacancies as well as C and O substitutes of N atoms

    NASA Astrophysics Data System (ADS)

    Zhukovskii, Y. F.; Bellucci, S.; Piskunov, S.; Trinkler, L.; Berzina, B.

    2009-02-01

    Defective single-walled BN nanotubes of armchair- and zigzag-type chiralities with uniform diameter can be simulated using a total geometry optimization for the 1D-periodic model. For calculations, we have applied the formalism of localized Gaussian-type atomic functions using the Hamiltonian containing hybrid (DFT+HF) non-local exchange-correlation functional B3PW as implemented in CRYSTAL code. Single N vacancy as well as C and O substitutes of N atom cause an appearance of the energy levels inside the BN NT band gap accompanied by relaxation of the nearest atomic spheres closest to the point defect and electronic charge redistribution around it.

  7. On State Complexes and Special Cube Complexes

    ERIC Educational Resources Information Center

    Peterson, Valerie J.

    2009-01-01

    This thesis presents the first steps toward a classification of non-positively curved cube complexes called state complexes. A "state complex" is a configuration space for a "reconfigurable system," i.e., an abstract system in which local movements occur in some discrete manner. Reconfigurable systems can be used to describe, for example,…

  8. On State Complexes and Special Cube Complexes

    ERIC Educational Resources Information Center

    Peterson, Valerie J.

    2009-01-01

    This thesis presents the first steps toward a classification of non-positively curved cube complexes called state complexes. A "state complex" is a configuration space for a "reconfigurable system," i.e., an abstract system in which local movements occur in some discrete manner. Reconfigurable systems can be used to describe, for example,…

  9. Discovery of Novel 11-Triazole Substituted Benzofuro[3,2-b]quinolone Derivatives as c-myc G-Quadruplex Specific Stabilizers via Click Chemistry.

    PubMed

    Zeng, De-Ying; Kuang, Guo-Tao; Wang, Shi-Ke; Peng, Wang; Lin, Shu-Ling; Zhang, Qi; Su, Xiao-Xuan; Hu, Ming-Hao; Wang, Honggen; Tan, Jia-Heng; Huang, Zhi-Shu; Gu, Lian-Quan; Ou, Tian-Miao

    2017-07-13

    The specificity of nucleic acids' binders is crucial for developing this kind of drug, especially for novel G-quadruplexes' binders. Quindoline derivatives have been developed as G-quadruplex stabilizers with good interactive activities. In order to improve the selectivity and binding affinity of quindoline derivatives as c-myc G-quadruplex binding ligands, novel triazole containing benzofuroquinoline derivatives (T-BFQs) were designed and synthesized by using the 1,3-dipolar cycloaddition of a series of alkyne and azide building blocks. The selectivity toward c-myc G-quadruplex DNA of these novel T-BFQs was significantly improved, together with an obvious increase on binding affinity. Further cellular and in vivo experiments indicated that the T-BFQs showed inhibitory activity on tumor cells' proliferation, presumably through the down-regulation of transcription of c-myc gene. Our findings broadened the modification strategies of specific G-quadruplex stabilizers.

  10. Natural complexity, computational complexity and depth.

    PubMed

    Machta, J

    2011-09-01

    Depth is a complexity measure for natural systems of the kind studied in statistical physics and is defined in terms of computational complexity. Depth quantifies the length of the shortest parallel computation required to construct a typical system state or history starting from simple initial conditions. The properties of depth are discussed and it is compared with other complexity measures. Depth can only be large for systems with embedded computation.

  11. [Complexity of land ecosystem].

    PubMed

    Wu, Cifang; Chen, Meiqiu

    2002-06-01

    In recent years, complexity studies has become a new research region and been widely applied in engineering, biology, economy, management, military, police and sociology. In this paper, from the view of complex science, the main complexity characteristics of land ecosystem were described, furthermore, the application of fractal, chaos, and artificial neural network on the complexity of land ecosystem were also discussed.

  12. Protein Complexes in Bacteria

    PubMed Central

    Caufield, J. Harry; Abreu, Marco; Wimble, Christopher; Uetz, Peter

    2015-01-01

    Large-scale analyses of protein complexes have recently become available for Escherichia coli and Mycoplasma pneumoniae, yielding 443 and 116 heteromultimeric soluble protein complexes, respectively. We have coupled the results of these mass spectrometry-characterized protein complexes with the 285 “gold standard” protein complexes identified by EcoCyc. A comparison with databases of gene orthology, conservation, and essentiality identified proteins conserved or lost in complexes of other species. For instance, of 285 “gold standard” protein complexes in E. coli, less than 10% are fully conserved among a set of 7 distantly-related bacterial “model” species. Complex conservation follows one of three models: well-conserved complexes, complexes with a conserved core, and complexes with partial conservation but no conserved core. Expanding the comparison to 894 distinct bacterial genomes illustrates fractional conservation and the limits of co-conservation among components of protein complexes: just 14 out of 285 model protein complexes are perfectly conserved across 95% of the genomes used, yet we predict more than 180 may be partially conserved across at least half of the genomes. No clear relationship between gene essentiality and protein complex conservation is observed, as even poorly conserved complexes contain a significant number of essential proteins. Finally, we identify 183 complexes containing well-conserved components and uncharacterized proteins which will be interesting targets for future experimental studies. PMID:25723151

  13. Complex networks analysis of language complexity

    NASA Astrophysics Data System (ADS)

    Amancio, Diego R.; Aluisio, Sandra M.; Oliveira, Osvaldo N., Jr.; Costa, Luciano da F.

    2012-12-01

    Methods from statistical physics, such as those involving complex networks, have been increasingly used in the quantitative analysis of linguistic phenomena. In this paper, we represented pieces of text with different levels of simplification in co-occurrence networks and found that topological regularity correlated negatively with textual complexity. Furthermore, in less complex texts the distance between concepts, represented as nodes, tended to decrease. The complex networks metrics were treated with multivariate pattern recognition techniques, which allowed us to distinguish between original texts and their simplified versions. For each original text, two simplified versions were generated manually with increasing number of simplification operations. As expected, distinction was easier for the strongly simplified versions, where the most relevant metrics were node strength, shortest paths and diversity. Also, the discrimination of complex texts was improved with higher hierarchical network metrics, thus pointing to the usefulness of considering wider contexts around the concepts. Though the accuracy rate in the distinction was not as high as in methods using deep linguistic knowledge, the complex network approach is still useful for a rapid screening of texts whenever assessing complexity is essential to guarantee accessibility to readers with limited reading ability.

  14. Evolution of biological complexity.

    PubMed

    Adami, C; Ofria, C; Collier, T C

    2000-04-25

    To make a case for or against a trend in the evolution of complexity in biological evolution, complexity needs to be both rigorously defined and measurable. A recent information-theoretic (but intuitively evident) definition identifies genomic complexity with the amount of information a sequence stores about its environment. We investigate the evolution of genomic complexity in populations of digital organisms and monitor in detail the evolutionary transitions that increase complexity. We show that, because natural selection forces genomes to behave as a natural "Maxwell Demon," within a fixed environment, genomic complexity is forced to increase.

  15. Evolution of biological complexity

    PubMed Central

    Adami, Christoph; Ofria, Charles; Collier, Travis C.

    2000-01-01

    To make a case for or against a trend in the evolution of complexity in biological evolution, complexity needs to be both rigorously defined and measurable. A recent information-theoretic (but intuitively evident) definition identifies genomic complexity with the amount of information a sequence stores about its environment. We investigate the evolution of genomic complexity in populations of digital organisms and monitor in detail the evolutionary transitions that increase complexity. We show that, because natural selection forces genomes to behave as a natural “Maxwell Demon,” within a fixed environment, genomic complexity is forced to increase. PMID:10781045

  16. Radioisotope trithiol complexes

    DOEpatents

    Jurisson, Silvia S.; Cutler, Cathy S.; Degraffenreid, Anthony J.

    2016-08-30

    The present invention is directed to a series of stable radioisotope trithiol complexes that provide a simplified route for the direct complexation of radioisotopes present in low concentrations. In certain embodiments, the complex contains a linking domain configured to conjugate the radioisotope trithiol complex to a targeting vector. The invention is also directed to a novel method of linking the radioisotope to a trithiol compound to form the radioisotope trithiol complex. The inventive radioisotope trithiol complexes may be utilized for a variety of applications, including diagnostics and/or treatment in nuclear medicine.

  17. Cyanobacterial NADPH dehydrogenase complexes

    SciTech Connect

    Ogawa, Teruo; Mi, Hualing

    2007-07-01

    Cyanobacteria possess functionally distinct multiple NADPH dehydrogenase (NDH-1) complexes that are essential to CO2 uptake, photosystem-1 cyclic electron transport and respiration. The unique nature of cyanobacterial NDH-1 complexes is the presence of subunits involved in CO2 uptake. Other than CO2 uptake, chloroplastic NDH-1 complex has similar role as cyanobacterial NDH-1 complexes in photosystem-1 cyclic electron transport and respiration (chlororespiration). In this mini-review we focus on the structure and function of cyanobacterial NDH-1 complexes and their phylogeny. The function of chloroplastic NDH-1 complex and characteristics of plants defective in NDH-1 are also described forcomparison.

  18. Adaptive Leadership: Fighting Complexity with Complexity

    DTIC Science & Technology

    2014-06-01

    Leader’s Framework for Decision Making,” 71. 24 Melanie Mitchell, Complexity: A Guided Tour (Oxford, UK: Oxford University Press, 2009), 12. 25...2011), 377. 29 Mitchell, Complexity: A Guided Tour. 30 Douglas Hofstadter, Gödel, Escher, Bach: An Eternal Golden Braid (New York: Penguin Books...A Guided Tour, 10. 34 Barabasi, Linked: How Everything is Connected to Everything Else and what it Means, 145. 13

  19. Oligocyclopentadienyl transition metal complexes

    SciTech Connect

    de Azevedo, Cristina G.; Vollhardt, K. Peter C.

    2002-01-18

    Synthesis, characterization, and reactivity studies of oligocyclopentadienyl transition metal complexes, namely those of fulvalene, tercyclopentadienyl, quatercyclopentadienyl, and pentacyclopentadienyl(cyclopentadienyl) are the subject of this account. Thermal-, photo-, and redox chemistries of homo- and heteropolynuclear complexes are described.

  20. Irinotecan Lipid Complex Injection

    MedlinePlus

    Irinotecan lipid complex is used in combination with other medications to treat pancreatic cancer that has spread to other ... worsened after treatment with other chemotherapy medications. Irinotecan lipid complex is in a class of antineoplastic medications ...

  1. Vincristine Lipid Complex Injection

    MedlinePlus

    Vincristine lipid complex is used to treat a certain type of acute lymphoblastic leukemia (ALL; a type of cancer ... least two different treatments with other medications. Vincristine lipid complex is in a class of medications called ...

  2. Daunorubicin Lipid Complex Injection

    MedlinePlus

    Daunorubicin lipid complex is used to treat advanced Kaposi's sarcoma (a type of cancer that causes abnormal tissue to ... body) related to acquired immunodeficiency syndrome (AIDS). Daunorubicin lipid complex is in a class of medications called ...

  3. Weighted growing simplicial complexes

    NASA Astrophysics Data System (ADS)

    Courtney, Owen T.; Bianconi, Ginestra

    2017-06-01

    Simplicial complexes describe collaboration networks, protein interaction networks, and brain networks and in general network structures in which the interactions can include more than two nodes. In real applications, often simplicial complexes are weighted. Here we propose a nonequilibrium model for weighted growing simplicial complexes. The proposed dynamics is able to generate weighted simplicial complexes with a rich interplay between weights and topology emerging not just at the level of nodes and links, but also at the level of faces of higher dimension.

  4. The nuclear pore complex

    PubMed Central

    Adam, Stephen A

    2001-01-01

    Nuclear pore complexes, the conduits for information exchange between the nucleus and cytoplasm, appear broadly similar in eukaryotes from yeast to human. Precisely how nuclear pore complexes regulate macromolecular and ionic traffic remains unknown, but recent advances in the identification and characterization of components of the complex by proteomics and genomics have provided new insights. PMID:11574060

  5. Crystallization of macromolecular complexes: combinatorial complex crystallization

    NASA Astrophysics Data System (ADS)

    Stura, Enrico A.; Graille, Marc; Charbonnier, Jean-Baptiste

    2001-11-01

    The usefulness of antibody complexation, as a way of increasing the chances of crystallization needs to be re-evaluated after many antibody complexes have been crystallized and their structure determined. It is somewhat striking that among these, only a small number is a complex with a large protein antigen. The problem is that the effort of raising, cleaving and purifying an Fab is rewarded only by an extra chance of getting crystals; depending on the relative likelihood of crystallization of the complexed and uncomplexed protein. The example of the complex between HIV gp120, CD4 and an Fab fragment from a neutralizing antibody suggests that further complexation of an antigen-antibody complex with a third protein could, by increasing the number of possible combinations, improve the likelihood of crystallization. We propose the use of Ig-binding proteins as a way of extending the method from HIV gp120 to all proteins for which there are monoclonal antibodies. We discuss this technique, combinatorial complex crystallization (CCC), as part of a multi-component system for the enhancement of crystallization of macromolecular complexes. The method makes use of single Ig-binding domains from Staphylococcus aureus protein A (SpA), Peptostreptococcus magnus protein L (PpL) and the streptococcal protein G (SpG). The generality of the method depends on the ability of these domains to interact with a large repertoire of antibodies without affecting antigen binding. There is strong evidence to suggest that these Ig-binding domains bind outside the antigen-combining site of the antibody without perturbing antigen binding. It is clear from the crystal structure of the single SpG domain complexed with an Fab that the interaction involves mainly the immunoglobulin CH1 domain, a region not involved in antigen recognition. We have recently determined the structure of the complex between a human Fab and the domain D from SpA and found that steric hindrance is unlikely even for large

  6. The Colletotrichum acutatum species complex

    PubMed Central

    Damm, U.; Cannon, P.F.; Woudenberg, J.H.C.; Crous, P.W.

    2012-01-01

    Colletotrichum acutatum is known as an important anthracnose pathogen of a wide range of host plants worldwide. Numerous studies have reported subgroups within the C. acutatum species complex. Multilocus molecular phylogenetic analysis (ITS, ACT, TUB2, CHS-1, GAPDH, HIS3) of 331 strains previously identified as C. acutatum and other related taxa, including strains from numerous hosts with wide geographic distributions, confirmed the molecular groups previously recognised and identified a series of novel taxa. Thirty-one species are accepted, of which 21 have not previously been recognised. Colletotrichum orchidophilum clusters basal to the C. acutatum species complex. There is a high phenotypic diversity within this complex, and some of the species appear to have preferences to specific hosts or geographical regions. Others appear to be plurivorous and are present in multiple regions. In this study, only C. salicis and C. rhombiforme formed sexual morphs in culture, although sexual morphs have been described from other taxa (especially as laboratory crosses), and there is evidence of hybridisation between different species. One species with similar morphology to C. acutatum but not belonging to this species complex was also described here as new, namely C. pseudoacutatum. Taxonomic novelties: New combinations - Colletotrichum limetticola (R.E. Clausen) Damm, P.F. Cannon & Crous, C. lupini (Bondar) Damm, P.F. Cannon & Crous, C. salicis (Fuckel) Damm, P.F. Cannon & Crous. New species - C. acerbum Damm, P.F. Cannon & Crous, C. australe Damm, P.F. Cannon & Crous, C. brisbanense Damm, P.F. Cannon & Crous, C. cosmi Damm, P.F. Cannon & Crous, C. costaricense Damm, P.F. Cannon & Crous, C. cuscutae Damm, P.F. Cannon & Crous, C. guajavae Damm, P.F. Cannon & Crous, C. indonesiense Damm, P.F. Cannon & Crous, C. johnstonii Damm, P.F. Cannon & Crous, C. kinghornii Damm, P.F. Cannon & Crous, C. laticiphilum Damm, P.F. Cannon & Crous, C. melonis Damm, P.F. Cannon & Crous, C

  7. Complex Correspondence Principle

    SciTech Connect

    Bender, Carl M.; Meisinger, Peter N.; Hook, Daniel W.; Wang Qinghai

    2010-02-12

    Quantum mechanics and classical mechanics are distinctly different theories, but the correspondence principle states that quantum particles behave classically in the limit of high quantum number. In recent years much research has been done on extending both quantum and classical mechanics into the complex domain. These complex extensions continue to exhibit a correspondence, and this correspondence becomes more pronounced in the complex domain. The association between complex quantum mechanics and complex classical mechanics is subtle and demonstrating this relationship requires the use of asymptotics beyond all orders.

  8. The Oriented Graph Complexes

    NASA Astrophysics Data System (ADS)

    Willwacher, Thomas

    2015-03-01

    The oriented graph complexes are complexes of directed graphs without directed cycles. They govern, for example, the quantization of Lie bialgebras and infinite dimensional deformation quantization. Similar to the ordinary graph complexes GC n introduced by Kontsevich they come in two essentially different versions, depending on the parity of n. It is shown that, surprisingly, the oriented graph complex is quasi-isomorphic to the ordinary commutative graph complex of opposite parity GC n-1, up to some known classes. This yields in particular a combinatorial description of the action of on Lie bialgebras, and shows that a cycle-free formality morphism in the sense of Shoikhet can be constructed rationally without reference to configuration space integrals. Curiously, the obstruction class in the oriented graph complex found by Shoikhet corresponds to the well known theta graph in the ordinary graph complex.

  9. Complex virial theorem and complex scaling

    SciTech Connect

    Junker, B.R.

    1983-06-01

    We present the simple generalization to complex energies of the normal global real scaling used for bound-state calculations to produce a variational energy which satisfies the virial theorem. We show that in two limiting cases, one or the other of which is almost always p satisfied in all calculations, the virially stabilized complex energy is sensitive to only the real part or the imaginary part of the complex virial expression. We then compute the virial expression for a number of wave functions for the 1s2s/sup 2/ /sup 2/S He/sup -/, 1s2s2p /sup 2/P/sup o/ He/sup -/, and 1s/sup 2/2s/sup 2/kp /sup 2/P/sup o/ Be/sup -/ resonances and the corresponding virially stabilized resonance energies. In all calculations one of the limiting cases was applicable.

  10. Assessing physiological complexity.

    PubMed

    Burggren, W W; Monticino, M G

    2005-09-01

    Physiologists both admire and fear complexity, but we have made relatively few attempts to understand it. Inherently complex systems are more difficult to study and less predictable. However, a deeper understanding of physiological systems can be achieved by modifying experimental design and analysis to account for complexity. We begin this essay with a tour of some mathematical views of complexity. After briefly exploring chaotic systems, information theory and emergent behavior, we reluctantly conclude that, while a mathematical view of complexity provides useful perspectives and some narrowly focused tools, there are too few generally practical take-home messages for physiologists studying complex systems. Consequently, we attempt to provide guidelines as to how complex systems might be best approached by physiologists. After describing complexity based on the sum of a physiological system's structures and processes, we highlight increasingly refined approaches based on the pattern of interactions between structures and processes. We then provide a series of examples illustrating how appreciating physiological complexity can improve physiological research, including choosing experimental models, guiding data collection, improving data interpretations and constructing more rigorous system models. Finally, we conclude with an invitation for physiologists, applied mathematicians and physicists to collaborate on describing, studying and learning from studies of physiological complexity.

  11. Modeling of polypeptide chains as C alpha chains, C alpha chains with C beta, and C alpha chains with ellipsoidal lateral chains.

    PubMed Central

    Fogolari, F; Esposito, G; Viglino, P; Cattarinussi, S

    1996-01-01

    In an effort to reduce the number of degrees of freedom necessary to describe a polypeptide chain we analyze the statistical behavior of polypeptide chains when represented as C alpha chains, C alpha chains with C beta atoms attached, and C alpha chains with rotational ellipsoids as models of side chains. A statistical analysis on a restricted data set of 75 unrelated protein structures is performed. The comparison of the database distributions with those obtained by model calculation on very short polypeptide stretches allows the dissection of local versus nonlocal features of the distributions. The database distribution of the bend angles of polypeptide chains of pseudo bonded C alpha atoms spans a restricted range of values and shows a bimodal structure. On the other hand, the torsion angles of the C alpha chain may assume almost all possible values. The distribution is bimodal, but with a much broader probability distribution than for bend angles. The C alpha - C beta vectors may be taken as representative of the orientation of the lateral chain, as the direction of the bond is close to the direction of the vector joining C alpha to the ad hoc defined center of the "steric mass" of the side chain. Interestingly, both the bend angle defined by C alpha i-C alpha i+1-C beta i+1 and the torsional angle offset of the pseudo-dihedral C alpha i-C alpha i+1-C alpha i+2-C beta i+2 with respect to C alpha i-C alpha i+1-C alpha i+2-C alpha i+3 span a limited range of values. The latter results show that it is possible to give a more realistic representation of polypeptide chains without introducing additional degrees of freedom, i.e., by just adding to the C alpha chain a C beta with given side-chain properties. However, a more realistic description of side chains may be attained by modeling side chains as rotational ellipsoids that have roughly the same orientation and steric hindrance. To this end, we define the steric mass of an atom as proportional to its van der

  12. Hypergraph coloring complexes.

    PubMed

    Breuer, Felix; Dall, Aaron; Kubitzke, Martina

    2012-08-28

    The aim of this paper is to generalize the notion of the coloring complex of a graph to hypergraphs. We present three different interpretations of those complexes-a purely combinatorial one and two geometric ones. It is shown, that most of the properties, which are known to be true for coloring complexes of graphs, break down in this more general setting, e.g., Cohen-Macaulayness and partitionability. Nevertheless, we are able to provide bounds for the [Formula: see text]- and [Formula: see text]-vectors of those complexes which yield new bounds on chromatic polynomials of hypergraphs. Moreover, though it is proven that the coloring complex of a hypergraph has a wedge decomposition, we provide an example showing that in general this decomposition is not homotopy equivalent to a wedge of spheres. In addition, we can completely characterize those hypergraphs whose coloring complex is connected.

  13. Complexation of Optoelectronic Systems

    NASA Astrophysics Data System (ADS)

    Boreisho, A. S.; Il‧in, M. Yu.; Konyaev, M. A.; Mikhailenko, A. S.; Morozov, A. V.; Strakhov, S. Yu.

    2016-05-01

    Problems of increasing the efficiency and the functionality of complex optoelectronic systems for monitoring real atmospheric conditions and of their use are discussed. It is shown by the example of a meteorological complex comprising an infrared wind-sensing lidar and an X-range Doppler radar that the complexation of probing systems working in different electromagnetic-radiation ranges opens up new opportunities for determining the meteorological parameters of a turbulent atmosphere and investigating the interaction of radiation with it.

  14. Visual complexity: a review.

    PubMed

    Donderi, Don C

    2006-01-01

    The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from research on single forms, form and texture arrays and visual displays. Form complexity and form probability are shown to be linked through their reciprocal relationship in complexity theory, which is in turn shown to be consistent with recent developments in perceptual learning and neural circuit theory. Directions for further research are suggested.

  15. Complexity and schizophrenia.

    PubMed

    Fernández, Alberto; Gómez, Carlos; Hornero, Roberto; López-Ibor, Juan José

    2013-08-01

    Complexity estimators have been broadly utilized in schizophrenia investigation. Early studies reported increased complexity in schizophrenia patients, associated with a higher variability or "irregularity" of their brain signals. However, further investigations showed reduced complexities, thus introducing a clear divergence. Nowadays, both increased and reduced complexity values are reported. The explanation of such divergence is a critical issue to understand the role of complexity measures in schizophrenia research. Considering previous arguments a complementary hypothesis is advanced: if the increased irregularity of schizophrenia patients' neurophysiological activity is assumed, a "natural" tendency to increased complexity in EEG and MEG scans should be expected, probably reflecting an abnormal neuronal firing pattern in some critical regions such as the frontal lobes. This "natural" tendency to increased complexity might be modulated by the interaction of three main factors: medication effects, symptomatology, and age effects. Therefore, young, medication-naïve, and highly symptomatic (positive symptoms) patients are expected to exhibit increased complexities. More importantly, the investigation of these interacting factors by means of complexity estimators might help to elucidate some of the neuropathological processes involved in schizophrenia.

  16. The Colletotrichum boninense species complex

    PubMed Central

    Damm, U.; Cannon, P.F.; Woudenberg, J.H.C.; Johnston, P.R.; Weir, B.S.; Tan, Y.P.; Shivas, R.G.; Crous, P.W.

    2012-01-01

    Although only recently described, Colletotrichum boninense is well established in literature as an anthracnose pathogen or endophyte of a diverse range of host plants worldwide. It is especially prominent on members of Amaryllidaceae, Orchidaceae, Proteaceae and Solanaceae. Reports from literature and preliminary studies using ITS sequence data indicated that C. boninense represents a species complex. A multilocus molecular phylogenetic analysis (ITS, ACT, TUB2, CHS-1, GAPDH, HIS3, CAL) of 86 strains previously identified as C. boninense and other related strains revealed 18 clades. These clades are recognised here as separate species, including C. boninense s. str., C. hippeastri, C. karstii and 12 previously undescribed species, C. annellatum, C. beeveri, C. brassicicola, C. brasiliense, C. colombiense, C. constrictum, C. cymbidiicola, C. dacrycarpi, C. novae-zelandiae, C. oncidii, C. parsonsiae and C. torulosum. Seven of the new species are only known from New Zealand, perhaps reflecting a sampling bias. The new combination C. phyllanthi was made, and C. dracaenae Petch was epitypified and the name replaced with C. petchii. Typical for species of the C. boninense species complex are the conidiogenous cells with rather prominent periclinal thickening that also sometimes extend to form a new conidiogenous locus or annellations as well as conidia that have a prominent basal scar. Many species in the C. boninense complex form teleomorphs in culture. Taxonomic novelties: New combination - Colletotrichum phyllanthi (H. Surendranath Pai) Damm, P.F. Cannon & Crous. Name replacement - C. petchii Damm, P.F. Cannon & Crous. New species - C. annellatum Damm, P.F. Cannon & Crous, C. beeveri Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. brassicicola Damm, P.F. Cannon & Crous, C. brasiliense Damm, P.F. Cannon, Crous & Massola, C. colombiense Damm, P.F. Cannon, Crous, C. constrictum Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. cymbidiicola Damm, P.F. Cannon

  17. Bacterial formate hydrogenlyase complex

    PubMed Central

    McDowall, Jennifer S.; Murphy, Bonnie J.; Haumann, Michael; Palmer, Tracy; Armstrong, Fraser A.; Sargent, Frank

    2014-01-01

    Under anaerobic conditions, Escherichia coli can carry out a mixed-acid fermentation that ultimately produces molecular hydrogen. The enzyme directly responsible for hydrogen production is the membrane-bound formate hydrogenlyase (FHL) complex, which links formate oxidation to proton reduction and has evolutionary links to Complex I, the NADH:quinone oxidoreductase. Although the genetics, maturation, and some biochemistry of FHL are understood, the protein complex has never been isolated in an intact form to allow biochemical analysis. In this work, genetic tools are reported that allow the facile isolation of FHL in a single chromatographic step. The core complex is shown to comprise HycE (a [NiFe] hydrogenase component termed Hyd-3), FdhF (the molybdenum-dependent formate dehydrogenase-H), and three iron-sulfur proteins: HycB, HycF, and HycG. A proportion of this core complex remains associated with HycC and HycD, which are polytopic integral membrane proteins believed to anchor the core complex to the cytoplasmic side of the membrane. As isolated, the FHL complex retains formate hydrogenlyase activity in vitro. Protein film electrochemistry experiments on Hyd-3 demonstrate that it has a unique ability among [NiFe] hydrogenases to catalyze production of H2 even at high partial pressures of H2. Understanding and harnessing the activity of the FHL complex is critical to advancing future biohydrogen research efforts. PMID:25157147

  18. U1A Complex

    SciTech Connect

    2014-10-28

    Some of the most sophisticated experiments in the stockpile stewardship program are conducted in an environmentally safe manner, nearly 1000 feet below the ground at the site. The U1a complex a sprawling underground laboratory and tunnel complex is home to a number of unique capabilities.

  19. The Tom Core Complex

    PubMed Central

    Ahting, Uwe; Thun, Clemens; Hegerl, Reiner; Typke, Dieter; Nargang, Frank E.; Neupert, Walter; Nussberger, Stephan

    1999-01-01

    Translocation of nuclear-encoded preproteins across the outer membrane of mitochondria is mediated by the multicomponent transmembrane TOM complex. We have isolated the TOM core complex of Neurospora crassa by removing the receptors Tom70 and Tom20 from the isolated TOM holo complex by treatment with the detergent dodecyl maltoside. It consists of Tom40, Tom22, and the small Tom components, Tom6 and Tom7. This core complex was also purified directly from mitochondria after solubilization with dodecyl maltoside. The TOM core complex has the characteristics of the general insertion pore; it contains high-conductance channels and binds preprotein in a targeting sequence-dependent manner. It forms a double ring structure that, in contrast to the holo complex, lacks the third density seen in the latter particles. Three-dimensional reconstruction by electron tomography exhibits two open pores traversing the complex with a diameter of ∼2.1 nm and a height of ∼7 nm. Tom40 is the key structural element of the TOM core complex. PMID:10579717

  20. COMPLEXITY IN ECOLOGICAL SYSTEMS

    EPA Science Inventory

    The enormous complexity of ecosystems is generally obvious under even the most cursory examination. In the modern world, this complexity is further augmented by the linkage of ecosystems to economic and social systems through the human use of the environment for technological pu...

  1. Performance Improvement Assuming Complexity

    ERIC Educational Resources Information Center

    Rowland, Gordon

    2007-01-01

    Individual performers, work teams, and organizations may be considered complex adaptive systems, while most current human performance technologies appear to assume simple determinism. This article explores the apparent mismatch and speculates on future efforts to enhance performance if complexity rather than simplicity is assumed. Included are…

  2. Complexity and Relations

    ERIC Educational Resources Information Center

    Lancaster, Jeanette Elizabeth

    2013-01-01

    A central feature of complexity is that it is based on non-linear, recursive relations. However, in most current accounts of complexity such relations, while non-linear, are based on the reductive relations of a Newtonian onto-epistemological framework. This means that the systems that are emergent from the workings of such relations are a…

  3. Visual Complexity: A Review

    ERIC Educational Resources Information Center

    Donderi, Don C.

    2006-01-01

    The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from…

  4. Visual Complexity: A Review

    ERIC Educational Resources Information Center

    Donderi, Don C.

    2006-01-01

    The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from…

  5. U1A Complex

    ScienceCinema

    None

    2016-07-12

    Some of the most sophisticated experiments in the stockpile stewardship program are conducted in an environmentally safe manner, nearly 1000 feet below the ground at the site. The U1a complex a sprawling underground laboratory and tunnel complex is home to a number of unique capabilities.

  6. Complexity and valued landscapes

    Treesearch

    Michael M. McCarthy

    1979-01-01

    The variable "complexity," or "diversity," has received a great deal of attention in recent research efforts concerned with visual resource management, including the identification of complexity as one of the primary evaluation measures. This paper describes research efforts that support the hypothesis that the landscapes we value are those with...

  7. Complexity and Relations

    ERIC Educational Resources Information Center

    Lancaster, Jeanette Elizabeth

    2013-01-01

    A central feature of complexity is that it is based on non-linear, recursive relations. However, in most current accounts of complexity such relations, while non-linear, are based on the reductive relations of a Newtonian onto-epistemological framework. This means that the systems that are emergent from the workings of such relations are a…

  8. COMPLEXITY IN ECOLOGICAL SYSTEMS

    EPA Science Inventory

    The enormous complexity of ecosystems is generally obvious under even the most cursory examination. In the modern world, this complexity is further augmented by the linkage of ecosystems to economic and social systems through the human use of the environment for technological pu...

  9. Complexity in Picture Books

    ERIC Educational Resources Information Center

    Sierschynski, Jarek; Louie, Belinda; Pughe, Bronwyn

    2015-01-01

    One of the key requirements of Common Core State Standards (CCSS) in English Language Arts is that students are able to read and access complex texts across all grade levels. The CCSS authors emphasize both the limitations and lack of accuracy in the current CCSS model of text complexity, calling for the development of new frameworks. In response…

  10. Performance Improvement Assuming Complexity

    ERIC Educational Resources Information Center

    Rowland, Gordon

    2007-01-01

    Individual performers, work teams, and organizations may be considered complex adaptive systems, while most current human performance technologies appear to assume simple determinism. This article explores the apparent mismatch and speculates on future efforts to enhance performance if complexity rather than simplicity is assumed. Included are…

  11. Complexity and emergent phenomena.

    PubMed

    Suki, Béla; Bates, Jason H T; Frey, Urs

    2011-04-01

    Complex biological systems operate under non-equilibrium conditions and exhibit emergent properties associated with correlated spatial and temporal structures. These properties may be individually unpredictable, but tend to be governed by power-law probability distributions and/or correlation. This article reviews the concepts that are invoked in the treatment of complex systems through a wide range of respiratory-related examples. Following a brief historical overview, some of the tools to characterize structural variabilities and temporal fluctuations associated with complex systems are introduced. By invoking the concept of percolation, the notion of multiscale behavior and related modeling issues are discussed. Spatial complexity is then examined in the airway and parenchymal structures with implications for gas exchange followed by a short glimpse of complexity at the cellular and subcellular network levels. Variability and complexity in the time domain are then reviewed in relation to temporal fluctuations in airway function. Next, an attempt is given to link spatial and temporal complexities through examples of airway opening and lung tissue viscoelasticity. Specific examples of possible and more direct clinical implications are also offered through examples of optimal future treatment of fibrosis, exacerbation risk prediction in asthma, and a novel method in mechanical ventilation. Finally, the potential role of the science of complexity in the future of physiology, biology, and medicine is discussed.

  12. Complexity: against systems.

    PubMed

    Chu, Dominique

    2011-09-01

    This article assumes a specific intuitive notion of complexity as a difficulty to generate and/or assess the plausibility of models. Based on this intuitive understanding of complexity, it identifies two main causes of complexity, namely, radical openness and contextuality. The former is the idea that there are no natural systems. The modeler always needs to draw artificial boundaries around phenomena to generate feasible models. Contextuality is intimately connected to the requirement to simplify models and to leave out most aspects. Complexity occurs when contextuality and radical openness cannot be contained that is when it is not clear where the boundaries of the system are and which abstractions are the correct ones. This concept of complexity is illustrated using a number of example from evolution.

  13. Hypergraph coloring complexes

    PubMed Central

    Breuer, Felix; Dall, Aaron; Kubitzke, Martina

    2012-01-01

    The aim of this paper is to generalize the notion of the coloring complex of a graph to hypergraphs. We present three different interpretations of those complexes–a purely combinatorial one and two geometric ones. It is shown, that most of the properties, which are known to be true for coloring complexes of graphs, break down in this more general setting, e.g., Cohen–Macaulayness and partitionability. Nevertheless, we are able to provide bounds for the f- and h-vectors of those complexes which yield new bounds on chromatic polynomials of hypergraphs. Moreover, though it is proven that the coloring complex of a hypergraph has a wedge decomposition, we provide an example showing that in general this decomposition is not homotopy equivalent to a wedge of spheres. In addition, we can completely characterize those hypergraphs whose coloring complex is connected. PMID:23483700

  14. Complexity and behavioral economics.

    PubMed

    Rosser, J Barkley; Rosser, Marina V

    2015-04-01

    This paper will consider the relationship between complexity economics and behavioral economics. A crucial key to this is to understand that Herbert Simon was both the founder of explicitly modern behavioral economics as well as one of the early developers of complexity theory. Bounded rationality was essentially derived from Simon's view of the impossibility of full rationality on the part of economic agents. Modern complexity theory through such approaches as agent-based modeling offers an approach to understanding behavioral economics by allowing for specific behavioral responses to be assigned to agents who interact within this context, even without full rationality. Other parts of modern complexity theory are considered in terms of their relationships with behavioral economics. Fundamentally, complexity provides an ultimate foundation for bounded rationality and hence the need to use behavioral economics in a broader array of contexts than most economists have thought appropriate.

  15. Selenophene transition metal complexes

    SciTech Connect

    White, Carter James

    1994-07-27

    This research shows that selenophene transition metal complexes have a chemistry that is similar to their thiophene analogs. Selenophene coordination has been demonstrated and confirmed by molecular structure in both the η5- and the η1(Se)-coordination modes. The reaction chemistry of selenophene complexes closely resembles that of the analogous thiophene complexes. One major difference, however, is that selenophene is a better donor ligand than thiophene making the selenophene complexes more stable than the corresponding thiophene complexes. The 77Se NMR chemical shift values for selenophene complexes fall within distinct regions primarily depending on the coordination mode of the selenophene ligand. In the final paper, the C-H bond activation of η1(S)-bound thiophenes, η1(S)-benzothiophene and η1(Se)-bound selenophenes has been demonstrated. The deprotonation and rearrangement of the η1(E)-bound ligand to the carbon bound L-yl complex readily occurs in the presence of base. Reprotonation with a strong acid gives a carbene complex that is unreactive towards nucleophilic attack at the carbene carbon and is stable towards exposure to air. The molecular structure of [Cp(NO)(PPh3)Re(2-benzothioenylcarbene)]O3SCF3 was determined and contains a Re-C bond with substantial double bond character. Methyl substitution for the thienylcarbene or selenylcarbene gives a carbene that rearranges thermally to give back the η1(E)-bound complex. Based on these model reactions, a new mechanism for the H/D exchange of thiophene over the hydrodesulfurization catalyst has been proposed.

  16. Complexity and robustness

    PubMed Central

    Carlson, J. M.; Doyle, John

    2002-01-01

    Highly optimized tolerance (HOT) was recently introduced as a conceptual framework to study fundamental aspects of complexity. HOT is motivated primarily by systems from biology and engineering and emphasizes, (i) highly structured, nongeneric, self-dissimilar internal configurations, and (ii) robust yet fragile external behavior. HOT claims these are the most important features of complexity and not accidents of evolution or artifices of engineering design but are inevitably intertwined and mutually reinforcing. In the spirit of this collection, our paper contrasts HOT with alternative perspectives on complexity, drawing on real-world examples and also model systems, particularly those from self-organized criticality. PMID:11875207

  17. Afterglow Complex Plasma

    SciTech Connect

    Samarian, A. A.; Boufendi, L.; Mikikian, M.

    2008-09-07

    The review of the first detailed experimental and theoretical studies of complex plasma in RF discharge afterglow is presented. The studies have been done in a frame of FAST collaborative research project between Complex Plasma Laboratory of the University of Sydney and the GREMI laboratory of Universite d'Orleans. We examined the existing models of plasma decay, presents experimental observations of dust dynamics under different afterglow complex plasma conditions, presents the experimental data obtained (in particular the presence of positively charged particles in discharge afterglow), discusses the use of dust particles as a probe to study the diffusion losses in afterglow plasmas.

  18. Complexity and forensic pathology.

    PubMed

    Jones, Richard Martin

    2015-12-01

    It has become increasingly apparent that nonlinearity and complexity are the norm in human physiological systems, the relevance of which is informing an enhanced understanding of basic pathological processes such as inflammation, the host response to severe trauma, and critical illness. This article will explore how an understanding of nonlinear systems and complexity might inform the study of the pathophysiology of deaths of medicolegal interest, and how 'complexity thinking' might usefully be incorporated into modern forensic medicine and forensic pathology research, education and practice.

  19. Complex and unpredictable Cardano

    NASA Astrophysics Data System (ADS)

    Ekert, Artur

    2008-08-01

    This purely recreational paper is about one of the most colorful characters of the Italian Renaissance, Girolamo Cardano, and the discovery of two basic ingredients of quantum theory, probability and complex numbers.

  20. Complex Flow Workshop Report

    SciTech Connect

    none,

    2012-05-01

    This report documents findings from a workshop on the impacts of complex wind flows in and out of wind turbine environments, the research needs, and the challenges of meteorological and engineering modeling at regional, wind plant, and wind turbine scales.

  1. Reconstruction Using Witness Complexes

    PubMed Central

    Oudot, Steve Y.

    2010-01-01

    We present a novel reconstruction algorithm that, given an input point set sampled from an object S, builds a one-parameter family of complexes that approximate S at different scales. At a high level, our method is very similar in spirit to Chew’s surface meshing algorithm, with one notable difference though: the restricted Delaunay triangulation is replaced by the witness complex, which makes our algorithm applicable in any metric space. To prove its correctness on curves and surfaces, we highlight the relationship between the witness complex and the restricted Delaunay triangulation in 2d and in 3d. Specifically, we prove that both complexes are equal in 2d and closely related in 3d, under some mild sampling assumptions. PMID:21643440

  2. Complex Regional Pain Syndrome

    MedlinePlus

    Complex regional pain syndrome (CRPS) is a chronic pain condition. It causes intense pain, usually in the arms, hands, legs, or feet. ... in skin temperature, color, or texture Intense burning pain Extreme skin sensitivity Swelling and stiffness in affected ...

  3. Doxorubicin Lipid Complex Injection

    MedlinePlus

    ... in combination with another chemotherapy drug to treat multiple myeloma (a type of cancer of the bone marrow) ... When doxorubicin lipid complex is used to treat multiple myeloma, it is given on certain days every 3 ...

  4. A complex legacy

    NASA Astrophysics Data System (ADS)

    Moore, Cristopher

    2011-11-01

    In his tragically short life, Alan Turing helped define what computing machines are capable of, and where they reach inherent limits. His legacy is still felt every day, in areas ranging from computational complexity theory to cryptography and quantum computing.

  5. Pigment-protein complexes

    SciTech Connect

    Siegelman, H W

    1980-01-01

    The photosynthetically-active pigment protein complexes of procaryotes and eucaryotes include chlorophyll proteins, carotenochlorophyll proteins, and biliproteins. They are either integral components or attached to photosynthetic membranes. Detergents are frequently required to solubilize the pigment-protein complexes. The membrane localization and detergent solubilization strongly suggest that the pigment-protein complexes are bound to the membranes by hydrophobic interactions. Hydrophobic interactions of proteins are characterized by an increase in entropy. Their bonding energy is directly related to temperature and ionic strength. Hydrophobic-interaction chromatography, a relatively new separation procedure, can furnish an important method for the purification of pigment-protein complexes. Phycobilisome purification and properties provide an example of the need to maintain hydrophobic interactions to preserve structure and function.

  6. Indicators: Physical Habitat Complexity

    EPA Pesticide Factsheets

    Physical habitat complexity measures the amount and variety of all types of cove at the water’s edge in lakes. In general, dense and varied shoreline habitat is able to support more diverse communities of aquatic life.

  7. DNA complexes: Durable binders

    NASA Astrophysics Data System (ADS)

    Urbach, Adam R.

    2011-11-01

    A tetra-intercalator compound that threads through a DNA double-helix to form a remarkably stable complex exhibits an unusual combination of sequence specificity and rapid association yet slow dissociation.

  8. An erupted complex odontoma.

    PubMed

    Tozoglu, Sinan; Yildirim, Umran; Buyukkurt, M Cemil

    2010-01-01

    Odontomas are benign tumors of odontogenic origin. The cause of the odontoma is unknown, but it is believed to be hereditary or due to a disturbance in tooth development triggered by trauma or infection. Odontomas may be either compound or complex. Although these tumors are seen frequently, erupted odontomas are rare. The purpose of this study is to present a rare case of complex odontoma that erupted into the oral cavity.

  9. Inside the complexity labyrinth

    NASA Astrophysics Data System (ADS)

    Fraser, Gordon

    2010-02-01

    Although the world we live in is complex, complexity as a science does not have a long history. For generations, most physicists tried to understand everything in terms of interactions between pairs of idealized "test particles". Then, about a 100 years ago, Henri Poincaré pointed out that a fully interacting three-body system was not just the sum of its three component pairs. The famous "three-body problem" was born.

  10. Electrospun complexes - functionalised nanofibres

    NASA Astrophysics Data System (ADS)

    Meyer, T.; Wolf, M.; Dreyer, B.; Unruh, D.; Krüger, C.; Menze, M.; Sindelar, R.; Klingelhöfer, G.; Renz, F.

    2016-12-01

    Here we present a new approach of using iron-complexes in electro-spun fibres. We modify poly(methyl methacrylate) (PMMA) by replacing the methoxy group with Diaminopropane or Ethylenediamine. The complex is bound covalently via an imine-bridge or an amide. The resulting polymer can be used in the electrospinning process without any further modifications in method either as pure reagent or mixed with small amounts of not functionalised polymer resulting in fibres of different qualities (Fig. 1).

  11. Pulling complexes out of complex diseases

    PubMed Central

    Mohan, Ryan D; Abmayr, Susan M; Workman, Jerry L

    2014-01-01

    Spinocerebellar ataxia 7 (SCA7) is an incurable disease caused by expansion of CAG trinucleotide sequences within the Ataxin-7 gene. This elongated CAG tract results in an Ataxin-7 protein bearing an expanded polyglutamine (PolyQ) repeat. SCA7 disease is characterized by progressive neural and retinal degeneration leading to ataxia and blindness. Evidence gathered from investigating SCA7 and other PolyQ diseases strongly suggest that misregulation of gene expression contributes to neurodegeneration. In fact, Ataxin-7 is a subunit of the essential Spt-Ada-Gcn5-Acetltransferase (SAGA) chromatin modifying complex that regulates expression of a large number of genes. Here we discuss recent insights into Ataxin-7 function and, considering these findings, propose a model for how polyglutamine expansion of Ataxin-7 may affect Ataxin-7 function to alter chromatin modifications and gene expression. PMID:25054097

  12. Neurogenesis in the water flea Daphnia magna (Crustacea, Branchiopoda) suggests different mechanisms of neuroblast formation in insects and crustaceans.

    PubMed

    Ungerer, Petra; Eriksson, Bo Joakim; Stollewerk, Angelika

    2011-09-01

    Within euarthropods, the morphological and molecular mechanisms of early nervous system development have been analysed in insects and several representatives of chelicerates and myriapods, while data on crustaceans are fragmentary. Neural stem cells (neuroblasts) generate the nervous system in insects and in higher crustaceans (malacostracans); in the remaining euarthropod groups, the chelicerates (e.g. spiders) and myriapods (e.g. millipedes), neuroblasts are missing. In the latter taxa, groups of neural precursors segregate from the neuroectoderm and directly differentiate into neurons and glial cells. In all euarthropod groups, achaete-scute homologues are required for neuroblast/neural precursor group formation. In the insects Drosophila melanogaster and Tribolium castaneum achaete-scute homologues are initially expressed in clusters of cells (proneural clusters) in the neuroepithelium but expression becomes restricted to the future neuroblast. Subsequently genes such as snail and prospero are expressed in the neuroblasts which are required for asymmetric division and differentiation. In contrast to insects, malacostracan neuroblasts do not segregate into the embryo but remain in the outer neuroepithelium, similar to vertebrate neural stem cells. It has been suggested that neuroblasts are present in another crustacean group, the branchiopods, and that they also remain in the neuroepithelium. This raises the questions how the molecular mechanisms of neuroblast selection have been modified during crustacean and insect evolution and if the segregation or the maintenance of neuroblasts in the neuroepithelium represents the ancestral state. Here we take advantage of the recently published Daphnia pulex (branchiopod) genome and identify genes in Daphnia magna that are known to be required for the selection and asymmetric division of neuroblasts in the fruit fly D. melanogaster. We unambiguously identify neuroblasts in D. magna by molecular marker gene expression and

  13. Proprotein convertase PACE4 is down-regulated by the basic helix-loop-helix transcription factor hASH-1 and MASH-1.

    PubMed

    Yoshida, I; Koide, S; Hasegawa, S I; Nakagawara, A; Tsuji, A; Matsuda, Y

    2001-12-15

    PACE4 is a mammalian subtilisin-like proprotein convertase that activates transforming growth factor (TGF)-beta-related proteins such as bone morphogenetic protein 2 (BMP2), BMP4 and Nodal and exhibits a dynamic expression pattern during embryogenesis. We recently determined that the 1 kb 5'-upstream region of the PACE4 gene contains 12 E-box (E1-E12) elements and that an E-box cluster (E4-E9) acts as a negative regulator [Tsuji, Yoshida, Hasegawa, Bando, Yoshida, Koide, Mori and Matsuda (1999) J. Biochem. (Tokyo) 126, 494-502]. It is known that the mammalian achaete-scute homologue 1 (MASH-1) binds specifically to an E-box (CACCTG) sequence in collaboration with E47, a ubiquitously expressed basic helix-loop-helix (bHLH) factor. To identify the roles of the bHLH factor and E-box elements in regulating PACE4 gene expression in neural development, we analysed the effects of human achaete-scute homologue 1 (hASH-1) on PACE4 gene expression with various neuroblastoma cell lines. The expressions of PACE4 and hASH-1 are correlated inversely in these cell lines. The overexpression of hASH-1 or MASH-1 causes a marked decrease in endogenous PACE4 gene expression but has no effect on the expression of other subtilisin-like proprotein convertases such as furin, PC5/6 and PC7/8. In contrast, other neural bHLH factors (MATH-1, MATH-2, neurogenin 1, neurogenin 2, neurogenin 3 and E47) did not affect PACE4 gene expression. Furthermore, an E-box cluster was a negative regulatory element for the promoter activity in NBL-S cells expressing hASH-1 at high level as determined by a luciferase assay. Binding of hASH-1 to the E-box cluster was confirmed by gel mobility-shift assay. In the present study we identified the PACE4 gene as one of the targets of hASH-1, which is a key factor in the initiation of neural differentiation. These results suggest that the alteration of PACE4 gene expression by hASH-1 causes rapid changes in the biological activities of TGF-beta-related proteins via

  14. Cell complexes through time

    NASA Astrophysics Data System (ADS)

    Klette, Reinhard

    2000-10-01

    The history of cell complexes is closely related to the birth and development of topology in general. Johann Benedict Listing (1802 - 1882) introduced the term 'topology' into mathematics in a paper published in 1847, and he also defined cell complexes for the first time in a paper published in 1862. Carl Friedrich Gauss (1777 - 1855) is often cited as the one who initiated these ideas, but he did not publish either on topology or on cell complexes. The pioneering work of Leonhard Euler (1707 - 1783) on graphs is also often cited as the birth of topology, and Euler's work was cited by Listing in 1862 as a stimulus for his research on cell complexes. There are different branches in topology which have little in common: point set topology, algebraic topology, differential topology etc. Confusion may arise if just 'topology' is specified, without clarifying the used concept. Topological subjects in mathematics are often related to continuous models, and therefore quite irrelevant to computer based solutions in image analysis. Compared to this, only a minority of topology publications in mathematics addresses discrete spaces which are appropriate for computer-based image analysis. In these cases, often the notion of a cell complex plays a crucial role. This paper briefly reports on a few of these publications. This paper is not intended to cover the very lively progress in cell complex studies within the context of image analysis during the last two decades. Basically it stops its historic review at the time when this subject in image analysis research gained speed in 1980 - 1990. As a general point of view, the paper indicates that image analysis contributes to a fusion of topological concepts, the geometric and the abstract cell structure approach and point set topology, which may lead towards new problems for the study of topologies defined on geometric or abstract cell complexes.

  15. Turbulent complex (dusty) plasma

    NASA Astrophysics Data System (ADS)

    Zhdanov, Sergey; Schwabe, Mierk

    2017-04-01

    As a paradigm of complex system dynamics, solid particles immersed into a weakly ionized plasma, so called complex (dusty) plasmas, were (and continue to be) a subject of many detailed studies. Special types of dynamical activity have been registered, in particular, spontaneous pairing, entanglement and cooperative action of a great number of particles resulting in formation of vortices, self-propelling, tunneling, and turbulent movements. In the size domain of 1-10 mkm normally used in experiments with complex plasmas, the characteristic dynamic time-scale is of the order of 0.01-0.1 s, and these particles can be visualized individually in real time, providing an atomistic (kinetic) level of investigations. The low-R turbulent flow induced either by the instability in a complex plasma cloud or formed behind a projectile passing through the cloud is a typical scenario. Our simulations showed formation of a fully developed system of vortices and demonstrated that the velocity structure functions scale very close to the theoretical predictions. As an important element of self-organization, cooperative and turbulent particle motions are present in many physical, astrophysical, and biological systems. Therefore, experiments with turbulent wakes and turbulent complex plasma oscillations are a promising mean to observe and study in detail the anomalous transport on the level of individual particles.

  16. Complexes and imagination.

    PubMed

    Kast, Verena

    2014-11-01

    Fantasies as imaginative activities are seen by Jung as expressions of psychic energy. In the various descriptions of active imagination the observation of the inner image and the dialogue with inner figures, if possible, are important. The model of symbol formation, as Jung describes it, can be experienced in doing active imagination. There is a correspondence between Jung's understanding of complexes and our imaginations: complexes develop a fantasy life. Complex episodes are narratives of difficult dysfunctional relationship episodes that have occurred repeatedly and are internalized with episodic memory. This means that the whole complex episode (the image for the child and the image for the aggressor, connected with emotions) is internalized and can get constellated in everyday relationship. Therefore inner dialogues do not necessarily qualify as active imaginations, often they are the expression of complex-episodes, very similar to fruitless soliloquies. If imaginations of this kind are repeated, new symbols and new possibilities of behaviour are not found. On the contrary, old patterns of behaviour and fantasies are perpetuated and become cemented. Imaginations of this kind need an intervention by the analyst. In clinical examples different kinds of imaginations are discussed. © 2014, The Society of Analytical Psychology.

  17. Hydridomethyl iridium complex

    DOEpatents

    Bergman, Robert G.; Buchanan, J. Michael; Stryker, Jeffrey M.; Wax, Michael J.

    1989-01-01

    A process for functionalizing methane comprising: (a) reacting methane with a hydridoalkyl metal complex of the formula: CpIr[P(R.sub.1).sub.3 ]H(R.sub.2) wherein Cp represents a cyclopentadienyl or alkylcyclopentadienyl radical having from 1 to 5 carbon atoms; Ir represents an iridium atom; P represents a phosphorus atom; R.sub.1 represents an alkyl group; R.sub.2 represents an alkyl group having at least two carbon atoms; and H represents a hydrogen atom, in the presence of a liquid alkane R.sub.3 H having at least three carbon atoms to form a hydridomethyl complex of the formula: CpIr[P(R.sub.1).sub.3 ]HMe where Me represents a methyl radical. (b) reacting said hydridomethyl complex with an organic halogenating agent such as a tetrahalomethane or a haloform of the formulas: CX'X"X'"X"" or CHX'X"X'"; wherein X', X", X"', and X"" represent halogens selected from bromine, iodine and chlorine, to halomethyl complex of step (a) having the formula: CpIr[P(R.sub.1).sub.3 ]MeX: (c) reacting said halomethyl complex with a mercuric halide of the formula HgX.sub.2 to form a methyl mercuric halide of the formula HgMeX; and (d) reacting said methyl mercuric halide with a molecular halogen of the formula X.sub.2 to form methyl halide.

  18. Quantum Complexity in Graphene

    NASA Astrophysics Data System (ADS)

    Baskaran, G.

    Carbon has a unique position among elements in the periodic table. It produces an allotrope, graphene, a mechanically robust two dimensional semimetal. The multifarious properties that graphene exhibits has few parallels among elemental metals. From simplicity, namely carbon atoms connected by pure sp2 bonds, a wealth of novel quantum properties emerge. In classical complex systems such as a spin glass or a finance market, several competing agents or elements are responsible for unanticipated and difficult to predict emergent properties. The complex (sic) structure of quantum mechanics is responsbile for an unanticipated set of emergent properties in graphene. We call this quantum complexity. In fact, most quantum systems, phenomena and modern quantum field theory could be viewed as examples of quantum complexity. After giving a brief introduction to the quantum complexity we focus on our own work, which indicates the breadth in the type of quantum phenomena that graphene could support. We review our theoretical suggestions of, (i) spin-1 collective mode in netural graphene, (ii) relativistic type of phenomena in crossed electric and magnetic fields, (iii) room temperature superconductivity in doped graphene and (iv) composite Fermi sea in neutral graphene in uniform magnetic field and (v) two-channel Kondo effect. Except for the relativistic type of phenomena, the rest depend in a fundamental way on a weak electron correlation that exists in the broad two-dimensional band of graphene.

  19. Quantum Complexity in Graphene

    NASA Astrophysics Data System (ADS)

    Baskaran, G.

    Carbon has a unique position among elements in the periodic table. It produces an allotrope, graphene, a mechanically robust two dimensional semimetal. The multifarious properties that graphene exhibits has few parallels among elemental metals. From simplicity, namely carbon atoms connected by pure sp2 bonds, a wealth of novel quantum properties emerge. In classical complex systems such as a spin glass or a finance market, several competing agents or elements are responsible for unanticipated and difficult to predict emergent properties. The complex (sic) structure of quantum mechanics is responsbile for an unanticipated set of emergent properties in graphene. We call this quantum complexity. Infact, most quantum systems, phenomena and modern quantum field theory could be viewed as examples of quantum complexity. After giving a brief introduction to the quantum complexity we focus on our own work, which indicates the breadth in the type of quantum phenomena that graphene could support. We review our theoretical suggestions of, (i) spin-1 collective mode in netural graphene, (ii) relativistic type of phenomena in crossed electric and magnetic fields, (iii) room temperature superconductivity in doped graphene and (iv) composite Fermi sea in neutral graphene in uniform magnetic field and (v) 2-channel Kondo effect. Except for the relativistic type of phenomena and Kondo effect, the rest depend in a fundamental way on a weak electron correlations that exist in graphene.

  20. Engineering complex tissues.

    PubMed

    Atala, Anthony; Kasper, F Kurtis; Mikos, Antonios G

    2012-11-14

    Tissue engineering has emerged at the intersection of numerous disciplines to meet a global clinical need for technologies to promote the regeneration of functional living tissues and organs. The complexity of many tissues and organs, coupled with confounding factors that may be associated with the injury or disease underlying the need for repair, is a challenge to traditional engineering approaches. Biomaterials, cells, and other factors are needed to design these constructs, but not all tissues are created equal. Flat tissues (skin); tubular structures (urethra); hollow, nontubular, viscus organs (vagina); and complex solid organs (liver) all present unique challenges in tissue engineering. This review highlights advances in tissue engineering technologies to enable regeneration of complex tissues and organs and to discuss how such innovative, engineered tissues can affect the clinic.

  1. Viral quasispecies complexity measures.

    PubMed

    Gregori, Josep; Perales, Celia; Rodriguez-Frias, Francisco; Esteban, Juan I; Quer, Josep; Domingo, Esteban

    2016-06-01

    Mutant spectrum dynamics (changes in the related mutants that compose viral populations) has a decisive impact on virus behavior. The several platforms of next generation sequencing (NGS) to study viral quasispecies offer a magnifying glass to study viral quasispecies complexity. Several parameters are available to quantify the complexity of mutant spectra, but they have limitations. Here we critically evaluate the information provided by several population diversity indices, and we propose the introduction of some new ones used in ecology. In particular we make a distinction between incidence, abundance and function measures of viral quasispecies composition. We suggest a multidimensional approach (complementary information contributed by adequately chosen indices), propose some guidelines, and illustrate the use of indices with a simple example. We apply the indices to three clinical samples of hepatitis C virus that display different population heterogeneity. Areas of virus biology in which population complexity plays a role are discussed.

  2. The complex pendulum

    NASA Astrophysics Data System (ADS)

    Bender, Carl M.

    1998-12-01

    In this talk we propose to broaden the conventional notion of quantum mechanics. In conventional quantum mechanics one imposes the condition H†=H, where † represents complex conjugation and matrix transpose, to ensure that the Hamiltonian has a real spectrum. Replacing this mathematical condition by the weaker and more physical requirement H‡=H, where ‡=PT represents combined parity reflection and time reversal, one obtains new infinite classes of complex Hamiltonians whose spectra are also real and positive. These PT-symmetric theories may be viewed as analytic continuations of conventional theories from real to complex phase space. This talk describes the unusual classical and quantum properties of PT-symmetric quantum mechanical and quantum field theoretic models.

  3. The complex pendulum

    NASA Astrophysics Data System (ADS)

    Bender, Carl M.

    1999-07-01

    This talk proposes a generalization of conventional quantum mechanics. In conventional quantum mechanics one imposes the condition H †=H , where † represents complex conjugation and matrix transpose, to ensure that the Hamiltonian has a real spectrum. By replacing this mathematical condition with the weaker and more physical requirement H ‡=H , where ‡= PT represents combined parity reflection and time reversal, one obtains new infinite classes of complex Hamiltonians whose spectra are also real and positive. These PT-symmetric theories may be viewed as analytic continuations of conventional theories from real to complex-phase space. This talk describes the unusual classical and quantum properties of PT-symmetric quantum-mechanical and quantum-field-theoretic models.

  4. Nonergodic complexity management

    NASA Astrophysics Data System (ADS)

    Piccinini, Nicola; Lambert, David; West, Bruce J.; Bologna, Mauro; Grigolini, Paolo

    2016-06-01

    Linear response theory, the backbone of nonequilibrium statistical physics, has recently been extended to explain how and why nonergodic renewal processes are insensitive to simple perturbations, such as in habituation. It was established that a permanent correlation results between an external stimulus and the response of a complex system generating nonergodic renewal processes, when the stimulus is a similar nonergodic process. This is the principle of complexity management, whose proof relies on ensemble distribution functions. Herein we extend the proof to the nonergodic case using time averages and a single time series, hence making it usable in real life situations where ensemble averages cannot be performed because of the very nature of the complex systems being studied.

  5. Alanine water complexes.

    PubMed

    Vaquero, Vanesa; Sanz, M Eugenia; Peña, Isabel; Mata, Santiago; Cabezas, Carlos; López, Juan C; Alonso, José L

    2014-04-10

    Two complexes of alanine with water, alanine-(H2O)n (n = 1,2), have been generated by laser ablation of the amino acid in a supersonic jet containing water vapor and characterized using Fourier transform microwave spectroscopy. In the observed complexes, water molecules bind to the carboxylic group of alanine acting as both proton donors and acceptors. In alanine-H2O, the water molecule establishes two intermolecular hydrogen bonds forming a six-membered cycle, while in alanine-(H2O)2 the two water molecules establish three hydrogen bonds forming an eight-membered ring. In both complexes, the amino acid moiety is in its neutral form and shows the conformation observed to be the most stable for the bare molecule. The microsolvation study of alanine-(H2O)n (n = 1,2) can be taken as a first step toward understanding bulk properties at a microscopic level.

  6. Synchronization in complex networks

    SciTech Connect

    Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C.; Kurths, J.

    2007-12-12

    Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.

  7. Universality classes of complexity

    NASA Astrophysics Data System (ADS)

    Saakian, David B.

    We give several criteria of complexity and define different universality classes. According to our classification, at the lowest class of complexity are random graph, Markov Models and Hidden Markov Models. At the next level is Sherrington-Kirkpatrick spin glass, connected with neuron-network models. On a higher level are critical theories, spin glass phase of Random Energy Model, percolation, self organized criticality (SOC). The top level class involves HOT design, error threshold in optimal coding, language, and, maybe, financial market. Alive systems are also related with the last class.

  8. Complexity and Fly Swarms

    NASA Astrophysics Data System (ADS)

    Cates, Grant; Murray, Joelle

    Complexity is the study of phenomena that emerge from a collection of interacting objects and arises in many systems throughout physics, biology, finance, economics and more. Certain kinds of complex systems can be described by self-organized criticality (SOC). An SOC system is one that is internally driven towards some critical state. Recent experimental work suggests scaling behavior of fly swarms-one of the hallmarks of an SOC system. Our goal is to look for SOC behavior in computational models of fly swarms.

  9. Luminescent macrocyclic lanthanide complexes

    DOEpatents

    Raymond, Kenneth N; Corneillie, Todd M; Xu, Jide

    2014-05-20

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  10. Luminescent macrocyclic lanthanide complexes

    DOEpatents

    Raymond, Kenneth N [Berkeley, CA; Corneillie, Todd M [Campbell, CA; Xu, Jide [Berkeley, CA

    2012-05-08

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  11. Electrostatically driven complexation

    NASA Astrophysics Data System (ADS)

    Netz, Roland

    2004-03-01

    Many biological and synthetic systems are electrically charged, which makes them soluble in aqueous environments. Often, electrostatic interactions are dominant, and lead to complexation (i.e. tight aggregation) of oppositely charged objects. As an example, charged polymers such as DNA exhibit a number of different complexation modes when mixed with other charged objects such as spheres or cylinders. A simple model for the complexation of semiflexible polyelectrolytes with oppositely charged spheres is considered, which can exhibit tightly wrapped polymer structures. Using the appropriate parameters for DNA-histone complexes, one finds complete wrapping for intermediate salt concentrations only, in agreement with experiments. The forces needed to pull the DNA off from histones show a plateau at 10-40 pN (depending on salt concentration). We also consider the interaction between such complexes, which have been measured using osmometry, and found to be attractive for intermediate salt concentration (suggesting precipitation) and repulsive elsewhere. Chain fluctuations can be treated within a normal-mode analysis and distinguish associated-unwrapped from dissociated structures. Since some time it is known that also similarly charged objects attract each other for sufficiently large surface-charge densities and/or in the presence of multivalent ions, a phenomenon not explicable within standard (Poisson-Boltzmann) approaches. The so-called strong-coupling theory, valid in the limit of large surface charge densities and for multi-valent ions, yields attraction between similarly charged walls, cylinders, and spheres in quantitative agreement with Monte-Carlo simulations. Charged complexes can be destroyed by applying an electric field, which is an important factor in understanding their electrophoresis. By performing dynamic simulations, the relation between the electrophoretic mobility and the non-equilibrium perturbation of the complex structure is investigated. 1

  12. The ESCRT Complexes

    PubMed Central

    Hurley, James H.

    2010-01-01

    The ESCRT machinery consists of the peripheral membrane protein complexes, ESCRT-0, -I, -II, -III, and Vps4-Vta1, and the ALIX homodimer. The ESCRT system is required for degradation of unneeded or dangerous plasma membrane proteins; biogenesis of the lysosome and the yeast vacuole; the budding of most membrane enveloped viruses; the membrane abscission step in cytokinesis; macroautophagy; and several other processes. From their initial discovery in 2001-2002, the literature on ESCRTs has grown exponentially. This review will describe the structure and function of the six complexes noted above and summarizes current knowledge of their mechanistic roles in cellular pathways and in disease. PMID:20653365

  13. The Corona Australis Complex.

    NASA Astrophysics Data System (ADS)

    Vaile, Roberta Anne

    What began as a HI study of the CrA star formation region has grown to incorporate the following: (1) a detailed investigation of the HI content of the CrA dark cloud; (2) an extensive molecular survey of the CrA dark cloud, from which the CrA molecular abundances were determined and compared to those of other Galactic environments; (3) an extensive HI survey of the CrA complex, which was compared to the established Galactic distributions in and near the region; (4) an examination of the extent and nature of the CrA IVCs, components of gas at intermediate, anomalous velocities; (5) an investigation of the correlations which may exist between the features of the CrA region; and (6) an evaluation of where the CrA complex fits within the framework of our understanding of the Galaxy. A review of our perceptions of the Galactic structure is contained in Chapter I. The established state of knowledge of the CrA dark cloud region--chiefly, that of a region of young and on-going star formation--is given in Chapter II. The observational studies of the CrA dark cloud region specifically are presented in Chapter III. The HI survey of the CrA complex is presented in Chapter IV, with the CrA IVCs results presented in Chapter V. A comparison of the CrA HI structure with nearby Galactic features suggests that the CrA complex--exemplified by the T_ {rm A} morphology given as a frontispiece and in Figure 4.1--is a coherently -moving HI structure falling subject to the Rayleigh-Taylor, Kelvin-Helmholtz, flute and Parker hydrodynamic and magnetohydrodynamic instabilities under the Galactic gravitational and differential rotation forces. As the distance to the CrA IVCs still remains speculative, no definitive identity for the CrA IVCs was established. Considering the whole, the CrA complex was interpreted as a feature triggered by the Sco-Cen association, possibly a late-comer to the Lindblad Ring and possibly a result of the Tau-Gem events. The similarities with the Oph northern

  14. Planning Complex Projects Automatically

    NASA Technical Reports Server (NTRS)

    Henke, Andrea L.; Stottler, Richard H.; Maher, Timothy P.

    1995-01-01

    Automated Manifest Planner (AMP) computer program applies combination of artificial-intelligence techniques to assist both expert and novice planners, reducing planning time by orders of magnitude. Gives planners flexibility to modify plans and constraints easily, without need for programming expertise. Developed specifically for planning space shuttle missions 5 to 10 years ahead, with modifications, applicable in general to planning other complex projects requiring scheduling of activities depending on other activities and/or timely allocation of resources. Adaptable to variety of complex scheduling problems in manufacturing, transportation, business, architecture, and construction.

  15. Tuberous sclerosis complex.

    PubMed

    DiMario, Francis J; Sahin, Mustafa; Ebrahimi-Fakhari, Darius

    2015-06-01

    Tuberous sclerosis complex is an autosomal-dominant, neurocutaneous, multisystem disorder characterized by cellular hyperplasia and tissue dysplasia. The genetic cause is mutations in the TSC1 gene, found on chromosome 9q34, and TSC2 gene, found on chromosome 16p13. The clinical phenotypes resulting from mutations in either of the 2 genes are variable in each individual. Herein, advances in the understanding of molecular mechanisms in tuberous sclerosis complex are reviewed, and current guidelines for diagnosis, treatment, follow-up, and management are summarized. Published by Elsevier Inc.

  16. Humic acid protein complexation

    NASA Astrophysics Data System (ADS)

    Tan, W. F.; Koopal, L. K.; Weng, L. P.; van Riemsdijk, W. H.; Norde, W.

    2008-04-01

    Interactions of purified Aldrich humic acid (PAHA) with lysozyme (LSZ) are investigated. In solution LSZ is moderately positively and PAHA negatively charged at the investigated pH values. The proton binding of PAHA and of LSZ is determined by potentiometric proton titrations at various KCl concentrations. It is also measured for two mixtures of PAHA-LSZ and compared with theoretically calculated proton binding assuming no mutual interaction. The charge adaptation due to PAHA-LSZ interaction is relatively small and only significant at low and high pH. Next to the proton binding, the mass ratio PAHA/LSZ at the iso-electric point (IEP) of the complex at given solution conditions is measured together with the pH using the Mütek particle charge detector. From the pH changes the charge adaptation due to the interaction can be found. Also these measurements show that the net charge adaptation is weak for PAHA-LSZ complexes at their IEP. PAHA/LSZ mass ratios in the complexes at the IEP are measured at pH 5 and 7. At pH 5 and 50 mmol/L KCl the charge of the complex is compensated for 30-40% by K +; at pH 7, where LSZ has a rather low positive charge, this is 45-55%. At pH 5 and 5 mmol/L KCl the PAHA/LSZ mass ratio at the IEP of the complex depends on the order of addition. When LSZ is added to PAHA about 25% K + is included in the complex, but no K + is incorporated when PAHA is added to LSZ. The flocculation behavior of the complexes is also different. After LSZ addition to PAHA slow precipitation occurs (6-24 h) in the IEP, but after addition of PAHA to LSZ no precipitation can be seen after 12 h. Clearly, PAHA/LSZ complexation and the colloidal stability of PAHA-LSZ aggregates depend on the order of addition. Some implications of the observed behavior are discussed.

  17. Cytoplasmic Viral Replication Complexes

    PubMed Central

    den Boon, Johan A.; Diaz, Arturo; Ahlquist, Paul

    2010-01-01

    Many viruses that replicate in the cytoplasm compartmentalize their genome replication and transcription in organelle-like structures that enhance replication efficiency and protection from host defenses. In particular, recent studies with diverse positive-strand RNA viruses have further elucidated the ultrastructure of membrane-bounded RNA replication complexes and their close coordination with virion assembly and budding. The structure, function and assembly of some positive-strand RNA virus replication complexes have parallels and potential evolutionary links with the replicative cores of double-strand RNA virus and retrovirus virions, and more general similarities with the replication factories of cytoplasmic DNA viruses. PMID:20638644

  18. Graphical Representation of Complex Functions.

    ERIC Educational Resources Information Center

    Renka, Robert J.

    1988-01-01

    Describes methods and software for graphing representation of a complex function of a complex variable. Includes an application of a graphical interpretation of the complex zeros of the cubic and their properties. (PK)

  19. Salen complexes with dianionic counterions

    DOEpatents

    Job, Gabriel E.; Farmer, Jay J.; Cherian, Anna E.

    2016-08-02

    The present invention describes metal salen complexes having dianionic counterions. Such complexes can be readily precipitated and provide an economical method for the purification and isolation of the complexes, and are useful to prepare novel polymer compositions.

  20. Nature, computation and complexity

    NASA Astrophysics Data System (ADS)

    Binder, P.-M.; Ellis, G. F. R.

    2016-06-01

    The issue of whether the unfolding of events in the world can be considered a computation is explored in this paper. We come to different conclusions for inert and for living systems (‘no’ and ‘qualified yes’, respectively). We suggest that physical computation as we know it exists only as a tool of complex biological systems: us.

  1. Launching Complex Tasks

    ERIC Educational Resources Information Center

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.

    2012-01-01

    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  2. Managing Complex Dynamical Systems

    ERIC Educational Resources Information Center

    Cox, John C.; Webster, Robert L.; Curry, Jeanie A.; Hammond, Kevin L.

    2011-01-01

    Management commonly engages in a variety of research designed to provide insight into the motivation and relationships of individuals, departments, organizations, etc. This paper demonstrates how the application of concepts associated with the analysis of complex systems applied to such data sets can yield enhanced insights for managerial action.

  3. Complex Planar Splines.

    DTIC Science & Technology

    1981-05-01

    try todefine a complex planar spline by holomorphic elements like polynomials, then by the well known identity theorem (e.g. Diederich- Remmert [9, p...R. Remmert : Funktionentheorie I, Springer, Berlin, Heidelberg, New York, 1972, 246 p. 10 0. Lehto - K.I. Virtanen: Quasikonforme AbbildunQen, Springer

  4. Accessibility in complex networks

    NASA Astrophysics Data System (ADS)

    Travençolo, B. A. N.; da F. Costa, L.

    2008-12-01

    This Letter describes a method for the quantification of the diversity of non-linear dynamics in complex networks as a consequence of self-avoiding random walks. The methodology is analyzed in the context of theoretical models and illustrated with respect to the characterization of the accessibility in urban streets.

  5. Subelliptic Estimates for Complexes

    PubMed Central

    Guillemin, Victor; Sternberg, Shlomo

    1970-01-01

    New results are announced linking properties of the symbol module and characteristic variety of a differential complex with test estimates near the characteristic variety of the type considered by Hörmander (½-estimate). The first result is the invariance of the test estimates under pseudo-differential change of coordinates, and this leads to the introduction of a normal form for the complex in the neighborhood of a Cohen-MacCauley point of the symbol module. If the characteristic variety V is a manifold near the Cohen-MacCauley point (x0,ζ0) with parametrizing functions p1,...,pq, where q is the codimension of the characteristic variety in the complexified contangent bundle, the matrix [Formula: see text] of Poisson brackets defines invariantly a Hermitian form Q on the normal space to V at (x0,ζ0) when the dpζ(x0,ζ0) are used as basis, and the test estimates are satisfied at the ith stage of the complex if sig. Q (signature of Q) is ≥ n - i + 1 (n the dimension of the base manifold) or rank Q - sig. Q ≥ i + 1. Finally, conditions are given in order that, on a manifold with smooth boundary, the associated boundary complexes satisfy the ½-estimate. PMID:16591855

  6. Complexity in Cultural Identity

    ERIC Educational Resources Information Center

    Holliday, Adrian

    2010-01-01

    Despite their diverse national backgrounds, 28 interviewees speak similarly about the complexity of the cultural realities with which they live, and refuse to be pinned down to specific cultural types. While nation is of great importance, unless personally inspiring, it tends to be an external force which is in conflict with a wide variety of…

  7. E Complex groundbreaking

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Representatives from NASA, Orbital Sciences Corp. and Aerojet participate in a ribbon-cutting ceremony for construction of a flame deflector trench at Stennis Space Center's E Test Complex. Participants included Orbital CEO J.R. Thompson (center, left) and Stennis Space Center Director Gene Goldman (center, right).

  8. Complexity, Systems, and Software

    DTIC Science & Technology

    2014-08-14

    2014 Carnegie Mellon University Complexity, Systems, and Software Software Engineering Institute Carnegie Mellon University Pittsburgh, PA...NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213 8...for the operation of the Software Engineering Institute, a federally funded research and development center sponsored by the United States

  9. Coordination Complexes of Cobalt.

    ERIC Educational Resources Information Center

    Williams, Gregory M.; And Others

    1989-01-01

    Described is an experiment involving the synthesis and spectral studies of cobalt complexes that not only give general chemistry students an introduction to inorganic synthesis but allows them to conduct a systematic study on the effect of different ligands on absorption spectra. Background information, procedures, and experimental results are…

  10. Cytarabine Lipid Complex Injection

    MedlinePlus

    ... used to treat lymphomatous meningitis (a type of cancer in the covering of the spinal cord and brain). Cytarabine lipid complex is in a class of medications called antimetabolites. It works by slowing or stopping the growth of cancer cells in your body.

  11. Restricting Grammatical Complexity

    ERIC Educational Resources Information Center

    Frank, Robert

    2004-01-01

    Theories of natural language syntax often characterize grammatical knowledge as a form of abstract computation. This paper argues that such a characterization is correct, and that fundamental properties of grammar can and should be understood in terms of restrictions on the complexity of possible grammatical computation, when defined in terms of…

  12. Analyzing Complex Survey Data.

    ERIC Educational Resources Information Center

    Rodgers-Farmer, Antoinette Y.; Davis, Diane

    2001-01-01

    Uses data from the 1994 AIDS Knowledge and Attitudes Supplement to the National Health Interview Survey (NHIS) to illustrate that biased point estimates, inappropriate standard errors, and misleading tests of significance can result from using traditional software packages, such as SPSS or SAS, for complex survey analysis. (BF)

  13. Complex Digital Visual Systems

    ERIC Educational Resources Information Center

    Sweeny, Robert W.

    2013-01-01

    This article identifies possibilities for data visualization as art educational research practice. The author presents an analysis of the relationship between works of art and digital visual culture, employing aspects of network analysis drawn from the work of Barabási, Newman, and Watts (2006) and Castells (1994). Describing complex network…

  14. Coordination Complexes of Cobalt.

    ERIC Educational Resources Information Center

    Williams, Gregory M.; And Others

    1989-01-01

    Described is an experiment involving the synthesis and spectral studies of cobalt complexes that not only give general chemistry students an introduction to inorganic synthesis but allows them to conduct a systematic study on the effect of different ligands on absorption spectra. Background information, procedures, and experimental results are…

  15. Complexity in Cultural Identity

    ERIC Educational Resources Information Center

    Holliday, Adrian

    2010-01-01

    Despite their diverse national backgrounds, 28 interviewees speak similarly about the complexity of the cultural realities with which they live, and refuse to be pinned down to specific cultural types. While nation is of great importance, unless personally inspiring, it tends to be an external force which is in conflict with a wide variety of…

  16. E Complex groundbreaking

    NASA Image and Video Library

    2009-04-14

    Representatives from NASA, Orbital Sciences Corp. and Aerojet participate in a ribbon-cutting ceremony for construction of a flame deflector trench at Stennis Space Center's E Test Complex. Participants included Orbital CEO J.R. Thompson (center, left) and Stennis Space Center Director Gene Goldman (center, right).

  17. Hydridomethyl iridium complex

    SciTech Connect

    Bergman, R.G; Buchanan, J.M.; Stryker, J.M.; Wax, M.J.

    1989-07-18

    This patent describes a hydridomethyl complex of the formula: CpIr(P(R{sub 1}){sub 3})HMe. Cp represents a cyclopentadienyl or alkyl cyclopentadienyl radical; Ir represents an iridium atom; P represents a phosphorus atom; R{sub 1} represents an alkyl group; and Me represents a methyl group.

  18. Complex Digital Visual Systems

    ERIC Educational Resources Information Center

    Sweeny, Robert W.

    2013-01-01

    This article identifies possibilities for data visualization as art educational research practice. The author presents an analysis of the relationship between works of art and digital visual culture, employing aspects of network analysis drawn from the work of Barabási, Newman, and Watts (2006) and Castells (1994). Describing complex network…

  19. The Complexity of Care

    ERIC Educational Resources Information Center

    Collins, Steve; Ting, Hermia

    2014-01-01

    The profession of teaching is unique because of the extent to which a teacher becomes involved in the lives of their "clients". The level of care required to support students well can be intense, confusing, and overwhelming. Relationships co-evolve within an ever-changing process and care is considered an essential aspect of complex relationships…

  20. Complex WS 2 nanostructures

    NASA Astrophysics Data System (ADS)

    Whitby, R. L. D.; Hsu, W. K.; Lee, T. H.; Boothroyd, C. B.; Kroto, H. W.; Walton, D. R. M.

    2002-06-01

    A range of elegant tubular and conical nanostructures has been created by template growth of (WS 2) n layers on the surfaces of single-walled carbon nanotube bundles. The structures exhibit remarkably perfect straight segments together with interesting complexities at the intersections, which are discussed here in detail in order to enhance understanding of the structural features governing tube growth.

  1. Complex Characters Made Simple

    ERIC Educational Resources Information Center

    Kettle, Sidney F. A.

    2009-01-01

    The physical significance of complex characters is explored with particular reference to the C[subscript 4] point group. While a diagrammatic representation of these characters in this group is possible, the extension to higher groups C[subscript n], n greater than 4 is left as a problem for discussion. (Contains 3 tables, 8 figures, and 1 note.)

  2. Complex Event Recognition Architecture

    NASA Technical Reports Server (NTRS)

    Fitzgerald, William A.; Firby, R. James

    2009-01-01

    Complex Event Recognition Architecture (CERA) is the name of a computational architecture, and software that implements the architecture, for recognizing complex event patterns that may be spread across multiple streams of input data. One of the main components of CERA is an intuitive event pattern language that simplifies what would otherwise be the complex, difficult tasks of creating logical descriptions of combinations of temporal events and defining rules for combining information from different sources over time. In this language, recognition patterns are defined in simple, declarative statements that combine point events from given input streams with those from other streams, using conjunction, disjunction, and negation. Patterns can be built on one another recursively to describe very rich, temporally extended combinations of events. Thereafter, a run-time matching algorithm in CERA efficiently matches these patterns against input data and signals when patterns are recognized. CERA can be used to monitor complex systems and to signal operators or initiate corrective actions when anomalous conditions are recognized. CERA can be run as a stand-alone monitoring system, or it can be integrated into a larger system to automatically trigger responses to changing environments or problematic situations.

  3. Complexity and Safety (FAA)

    DTIC Science & Technology

    2016-10-27

    into “How much can we discount the complexity of a system given that X% has been used before?” can be framed as “ credit for precedence” and ties to...capability component compared to existing? Other areas can contribute: • How organizations today currently allow credit for testing already done - FAA and

  4. Surface complexation modeling

    USDA-ARS?s Scientific Manuscript database

    Adsorption-desorption reactions are important processes that affect the transport of contaminants in the environment. Surface complexation models are chemical models that can account for the effects of variable chemical conditions, such as pH, on adsorption reactions. These models define specific ...

  5. Debating complexity in modeling

    USGS Publications Warehouse

    Hunt, Randall J.; Zheng, Chunmiao

    1999-01-01

    As scientists trying to understand the natural world, how should our effort be apportioned? We know that the natural world is characterized by complex and interrelated processes. Yet do we need to explicitly incorporate these intricacies to perform the tasks we are charged with? In this era of expanding computer power and development of sophisticated preprocessors and postprocessors, are bigger machines making better models? Put another way, do we understand the natural world better now with all these advancements in our simulation ability? Today the public's patience for long-term projects producing indeterminate results is wearing thin. This increases pressure on the investigator to use the appropriate technology efficiently. On the other hand, bringing scientific results into the legal arena opens up a new dimension to the issue: to the layperson, a tool that includes more of the complexity known to exist in the real world is expected to provide the more scientifically valid answer.

  6. Compressively sensed complex networks.

    SciTech Connect

    Dunlavy, Daniel M.; Ray, Jaideep; Pinar, Ali

    2010-07-01

    The aim of this project is to develop low dimension parametric (deterministic) models of complex networks, to use compressive sensing (CS) and multiscale analysis to do so and to exploit the structure of complex networks (some are self-similar under coarsening). CS provides a new way of sampling and reconstructing networks. The approach is based on multiresolution decomposition of the adjacency matrix and its efficient sampling. It requires preprocessing of the adjacency matrix to make it 'blocky' which is the biggest (combinatorial) algorithm challenge. Current CS reconstruction algorithm makes no use of the structure of a graph, its very general (and so not very efficient/customized). Other model-based CS techniques exist, but not yet adapted to networks. Obvious starting point for future work is to increase the efficiency of reconstruction.

  7. Carney Complex: an update

    PubMed Central

    Correa, Ricardo; Salpea, Paraskevi; Stratakis, Constantine

    2015-01-01

    Carney Complex (CNC) is a rare autosomal dominant syndrome, characterized by pigmented lesions of the skin and mucosa, cardiac, cutaneous and other myxomas, and multiple endocrine tumors. The disease is caused by inactivating mutations or large deletions of the PRKAR1A gene located at 17q22–24 coding for the regulatory subunit type I alpha of protein kinase A (PKA) gene. Most recently, components of the complex have been associated with defects of other PKA subunits, such as the catalytic subunits PRKACA (adrenal hyperplasia) and PRKACB (pigmented spots, myxomas, pituitary adenomas). In this report, we review CNC, its clinical features, diagnosis, treatment, and molecular etiology including PRKAR1A mutations and the newest on PRKACA and PRKACB defects especially as they pertain to adrenal tumors and Cushing’s syndrome. PMID:26130139

  8. Immunization of complex networks

    NASA Astrophysics Data System (ADS)

    Pastor-Satorras, Romualdo; Vespignani, Alessandro

    2002-03-01

    Complex networks such as the sexual partnership web or the Internet often show a high degree of redundancy and heterogeneity in their connectivity properties. This peculiar connectivity provides an ideal environment for the spreading of infective agents. Here we show that the random uniform immunization of individuals does not lead to the eradication of infections in all complex networks. Namely, networks with scale-free properties do not acquire global immunity from major epidemic outbreaks even in the presence of unrealistically high densities of randomly immunized individuals. The absence of any critical immunization threshold is due to the unbounded connectivity fluctuations of scale-free networks. Successful immunization strategies can be developed only by taking into account the inhomogeneous connectivity properties of scale-free networks. In particular, targeted immunization schemes, based on the nodes' connectivity hierarchy, sharply lower the network's vulnerability to epidemic attacks.

  9. Reducing GWAS Complexity

    PubMed Central

    Hazelett, Dennis J.; Conti, David V.; Han, Ying; Al Olama, Ali Amin; Easton, Doug; Eeles, Rosalind A.; Kote-Jarai, Zsofia; Haiman, Christopher A.; Coetzee, Gerhard A.

    2016-01-01

    ABSTRACT Genome-wide association studies (GWAS) have revealed numerous genomic 'hits' associated with complex phenotypes. In most cases these hits, along with surrogate genetic variation as measure by numerous single nucleotide polymorphisms (SNPs) that are in linkage disequilibrium, are not in coding genes making assignment of functionality or causality intractable. Here we propose that fine-mapping along with the matching of risk SNPs at chromatin biofeatures lessen this complexity by reducing the number of candidate functional/causal SNPs. For example, we show here that only on average 2 SNPs per prostate cancer risk locus are likely candidates for functionality/causality; we further propose that this manageable number should be taken forward in mechanistic studies. The candidate SNPs can be looked up for each prostate cancer risk region in 2 recent publications in 20151,2 from our groups. PMID:26771711

  10. Oscillations of complex networks

    NASA Astrophysics Data System (ADS)

    Wang, Xingang; Lai, Ying-Cheng; Lai, Choy Heng

    2006-12-01

    A complex network processing information or physical flows is usually characterized by a number of macroscopic quantities such as the diameter and the betweenness centrality. An issue of significant theoretical and practical interest is how such quantities respond to sudden changes caused by attacks or disturbances in recoverable networks, i.e., functions of the affected nodes are only temporarily disabled or partially limited. By introducing a model to address this issue, we find that, for a finite-capacity network, perturbations can cause the network to oscillate persistently in the sense that the characterizing quantities vary periodically or randomly with time. We provide a theoretical estimate of the critical capacity-parameter value for the onset of the network oscillation. The finding is expected to have broad implications as it suggests that complex networks may be structurally highly dynamic.

  11. Complexity in Dynamical Systems

    NASA Astrophysics Data System (ADS)

    Moore, Cristopher David

    The study of chaos has shown us that deterministic systems can have a kind of unpredictability, based on a limited knowledge of their initial conditions; after a finite time, the motion appears essentially random. This observation has inspired a general interest in the subject of unpredictability, and more generally, complexity; how can we characterize how "complex" a dynamical system is?. In this thesis, we attempt to answer this question with a paradigm of complexity that comes from computer science, we extract sets of symbol sequences, or languages, from a dynamical system using standard methods of symbolic dynamics; we then ask what kinds of grammars or automata are needed a generate these languages. This places them in the Chomsky heirarchy, which in turn tells us something about how subtle and complex the dynamical system's behavior is. This gives us insight into the question of unpredictability, since these automata can also be thought of as computers attempting to predict the system. In the culmination of the thesis, we find a class of smooth, two-dimensional maps which are equivalent to the highest class in the Chomsky heirarchy, the turning machine; they are capable of universal computation. Therefore, these systems possess a kind of unpredictability qualitatively different from the usual "chaos": even if the initial conditions are known exactly, questions about the system's long-term dynamics are undecidable. No algorithm exists to answer them. Although this kind of unpredictability has been discussed in the context of distributed, many-degree-of -freedom systems (for instance, cellular automata) we believe this is the first example of such phenomena in a smooth, finite-degree-of-freedom system.

  12. Feline respiratory disease complex.

    PubMed

    Cohn, Leah A

    2011-11-01

    Feline respiratory disease complex (FRDC) refers to the characteristic acute presentation of a contagious respiratory or ocular disease caused by one or multiple pathogens. Environmental and host factors impact the transmission, clinical presentation, preventive strategy, and treatment of affected cats. The FRDC is especially problematic in settings where large numbers of cats cohabit, including animal shelters, catteries, and semi-feral colonies. Although elimination of FRDC is an unrealistic goal, improved understanding can lead to strategies to minimize disease impact.

  13. Complex spatiotemporal convection patterns

    NASA Astrophysics Data System (ADS)

    Pesch, W.

    1996-09-01

    This paper reviews recent efforts to describe complex patterns in isotropic fluids (Rayleigh-Bénard convection) as well as in anisotropic liquid crystals (electro-hydrodynamic convection) when driven away from equilibrium. A numerical scheme for solving the full hydrodynamic equations is presented that allows surprisingly well for a detailed comparison with experiments. The approach can also be useful for a systematic construction of models (order parameter equations).

  14. The Complex Information Process

    NASA Astrophysics Data System (ADS)

    Taborsky, Edwina

    2000-09-01

    This paper examines the semiosic development of energy to information within a dyadic reality that operates within the contradictions of both classical and quantum physics. These two realities are examined within the three Peircean modal categories of Firstness, Secondness and Thirdness. The paper concludes that our world cannot operate within either of the two physical realities but instead filiates the two to permit a semiosis or information-generation of complex systems.

  15. Complex Flows by Nanohydrodynamics

    SciTech Connect

    Alley, E; Covello, P; Alder, B

    2004-03-01

    The study of complex flows by particle simulations is speeded up over molecular dynamics (MD) by more than two orders of magnitude by employing a stochastic collision dynamics method (DSMC) extended to high density (CBA). As a consequence, a picture generated on a single processor shows the typical features of the Rayleigh-Taylor instability and is in quantitative agreement with the experimentally found long time behavior.

  16. [Complex vascular access].

    PubMed

    Mangiarotti, G; Cesano, G; Thea, A; Hamido, D; Pacitti, A; Segoloni, G P

    1998-03-01

    Availability of a proper vascular access is a basic condition for a proper extracorporeal replacement in end-stage chronic renal failure. However, biological factors, management and other problems, may variously condition their middle-long term survival. Therefore, personal experience of over 25 years has been critically reviewed in order to obtain useful information. In particular "hard" situations necessitating complex procedures have been examined but, if possible, preserving the peripherical vascular features.

  17. Sporadic meteoroid complex: Modeling

    NASA Astrophysics Data System (ADS)

    Andreev, V.

    2014-07-01

    The distribution of the sporadic meteoroids flux density over the celestial sphere is the common form of representation of the meteoroids distribution in the vicinity of the Earth's orbit. The determination of the flux density of sporadic meteor bodies is Q(V,e,f) = Q_0 P_e(V) P(e,f) where V is the meteoroid velocity, e,f are the radiant coordinates, Q_0 is the meteoroid flux over whole celestial sphere, P_e(V) is the conditional velocity distributions and P(e,f) is the radiant distribution over the celestial sphere. The sporadic meteoroid complex model is analytical and based on heliocentric velocities and radiant distributions. The multi-mode character of the heliocentric velocity and radiant distributions follows from the analysis of meteor observational data. This fact points to a complicated structure of the sporadic meteoroid complex. It is the consequence of the plurality of the parent bodies and the origin mechanisms of the meteoroids. The meteoroid complex was divided into four groups for that reason and with a goal of more accurate modelling of velocities and radiant distributions. As the classifying parameter to determine the meteoroid membership in any group, we adopt the Tisserand invariant relative to Jupiter T_J = 1/a + 2 A_J^{-3/2} √{a (1 - e^2)} cos i and the meteoroid orbit inclination i. Two meteoroid groups relate to long-period and short-period comets. One meteoroid group is related to asteroids. The relationship to the last, fourth group is a problematic one. Then, we construct models of radiant and velocity distributions for each group. The analytical model for the whole sporadic meteoroid complex is the sum of the ones for each group.

  18. Engineering Complex Tissues

    PubMed Central

    MIKOS, ANTONIOS G.; HERRING, SUSAN W.; OCHAREON, PANNEE; ELISSEEFF, JENNIFER; LU, HELEN H.; KANDEL, RITA; SCHOEN, FREDERICK J.; TONER, MEHMET; MOONEY, DAVID; ATALA, ANTHONY; VAN DYKE, MARK E.; KAPLAN, DAVID; VUNJAK-NOVAKOVIC, GORDANA

    2010-01-01

    This article summarizes the views expressed at the third session of the workshop “Tissue Engineering—The Next Generation,” which was devoted to the engineering of complex tissue structures. Antonios Mikos described the engineering of complex oral and craniofacial tissues as a “guided interplay” between biomaterial scaffolds, growth factors, and local cell populations toward the restoration of the original architecture and function of complex tissues. Susan Herring, reviewing osteogenesis and vasculogenesis, explained that the vascular arrangement precedes and dictates the architecture of the new bone, and proposed that engineering of osseous tissues might benefit from preconstruction of an appropriate vasculature. Jennifer Elisseeff explored the formation of complex tissue structures based on the example of stratified cartilage engineered using stem cells and hydrogels. Helen Lu discussed engineering of tissue interfaces, a problem critical for biological fixation of tendons and ligaments, and the development of a new generation of fixation devices. Rita Kandel discussed the challenges related to the re-creation of the cartilage-bone interface, in the context of tissue engineered joint repair. Frederick Schoen emphasized, in the context of heart valve engineering, the need for including the requirements derived from “adult biology” of tissue remodeling and establishing reliable early predictors of success or failure of tissue engineered implants. Mehmet Toner presented a review of biopreservation techniques and stressed that a new breakthrough in this field may be necessary to meet all the needs of tissue engineering. David Mooney described systems providing temporal and spatial regulation of growth factor availability, which may find utility in virtually all tissue engineering and regeneration applications, including directed in vitro and in vivo vascularization of tissues. Anthony Atala offered a clinician’s perspective for functional tissue

  19. Classification of Software Projects' Complexity

    NASA Astrophysics Data System (ADS)

    Fitsilis, P.; Kameas, A.; Anthopoulos, L.

    Software project complexity is a subject that has not received detailed attention. The purpose of this chapter is to present a systematic way for studying and modeling software project complexity. The proposed model is based on the widely known and accepted Project Management Body of Knowledge and it uses a typology for modeling complexity based on complexity of faith, fact, and interaction.

  20. Statistical Factors in Complexation Reactions.

    ERIC Educational Resources Information Center

    Chung, Chung-Sun

    1985-01-01

    Four cases which illustrate statistical factors in complexation reactions (where two of the reactants are monodentate ligands) are presented. Included are tables showing statistical factors for the reactions of: (1) square-planar complexes; (2) tetrahedral complexes; and (3) octahedral complexes. (JN)

  1. Complexity Leadership: A Theoretical Perspective

    ERIC Educational Resources Information Center

    Baltaci, Ali; Balci, Ali

    2017-01-01

    Complex systems are social networks composed of interactive employees interconnected through collaborative, dynamic ties such as shared goals, perspectives and needs. Complex systems are largely based on "the complex system theory". The complex system theory focuses mainly on finding out and developing strategies and behaviours that…

  2. Observability of complex systems

    PubMed Central

    Liu, Yang-Yu; Slotine, Jean-Jacques; Barabási, Albert-László

    2013-01-01

    A quantitative description of a complex system is inherently limited by our ability to estimate the system’s internal state from experimentally accessible outputs. Although the simultaneous measurement of all internal variables, like all metabolite concentrations in a cell, offers a complete description of a system’s state, in practice experimental access is limited to only a subset of variables, or sensors. A system is called observable if we can reconstruct the system’s complete internal state from its outputs. Here, we adopt a graphical approach derived from the dynamical laws that govern a system to determine the sensors that are necessary to reconstruct the full internal state of a complex system. We apply this approach to biochemical reaction systems, finding that the identified sensors are not only necessary but also sufficient for observability. The developed approach can also identify the optimal sensors for target or partial observability, helping us reconstruct selected state variables from appropriately chosen outputs, a prerequisite for optimal biomarker design. Given the fundamental role observability plays in complex systems, these results offer avenues to systematically explore the dynamics of a wide range of natural, technological and socioeconomic systems. PMID:23359701

  3. Manufacturing complexity analysis

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1977-01-01

    The analysis of the complexity of a typical system is presented. Starting with the subsystems of an example system, the step-by-step procedure for analysis of the complexity of an overall system is given. The learning curves for the various subsystems are determined as well as the concurrent numbers of relevant design parameters. Then trend curves are plotted for the learning curve slopes versus the various design-oriented parameters, e.g. number of parts versus slope of learning curve, or number of fasteners versus slope of learning curve, etc. Representative cuts are taken from each trend curve, and a figure-of-merit analysis is made for each of the subsystems. Based on these values, a characteristic curve is plotted which is indicative of the complexity of the particular subsystem. Each such characteristic curve is based on a universe of trend curve data taken from data points observed for the subsystem in question. Thus, a characteristic curve is developed for each of the subsystems in the overall system.

  4. Advanced complex trait analysis.

    PubMed

    Gray, A; Stewart, I; Tenesa, A

    2012-12-01

    The Genome-wide Complex Trait Analysis (GCTA) software package can quantify the contribution of genetic variation to phenotypic variation for complex traits. However, as those datasets of interest continue to increase in size, GCTA becomes increasingly computationally prohibitive. We present an adapted version, Advanced Complex Trait Analysis (ACTA), demonstrating dramatically improved performance. We restructure the genetic relationship matrix (GRM) estimation phase of the code and introduce the highly optimized parallel Basic Linear Algebra Subprograms (BLAS) library combined with manual parallelization and optimization. We introduce the Linear Algebra PACKage (LAPACK) library into the restricted maximum likelihood (REML) analysis stage. For a test case with 8999 individuals and 279,435 single nucleotide polymorphisms (SNPs), we reduce the total runtime, using a compute node with two multi-core Intel Nehalem CPUs, from ∼17 h to ∼11 min. The source code is fully available under the GNU Public License, along with Linux binaries. For more information see http://www.epcc.ed.ac.uk/software-products/acta. a.gray@ed.ac.uk Supplementary data are available at Bioinformatics online.

  5. Predictive Surface Complexation Modeling

    SciTech Connect

    Sverjensky, Dimitri A.

    2016-11-29

    Surface complexation plays an important role in the equilibria and kinetics of processes controlling the compositions of soilwaters and groundwaters, the fate of contaminants in groundwaters, and the subsurface storage of CO2 and nuclear waste. Over the last several decades, many dozens of individual experimental studies have addressed aspects of surface complexation that have contributed to an increased understanding of its role in natural systems. However, there has been no previous attempt to develop a model of surface complexation that can be used to link all the experimental studies in order to place them on a predictive basis. Overall, my research has successfully integrated the results of the work of many experimentalists published over several decades. For the first time in studies of the geochemistry of the mineral-water interface, a practical predictive capability for modeling has become available. The predictive correlations developed in my research now enable extrapolations of experimental studies to provide estimates of surface chemistry for systems not yet studied experimentally and for natural and anthropogenically perturbed systems.

  6. Coherence, Complexity and Creativity

    NASA Astrophysics Data System (ADS)

    Arecchi, Fortunato Tito

    We review the ideas and experiments that established the onset of laser coherence beyond a suitable threshold. That threshold is the first of a chain of bifurcations in a non linear dynamics, leading eventually to deterministic chaos in lasers. In particular, the so called HC behavior has striking analogies with the electrical activity of neurons. Based on these considerations, we develop a dynamical model of neuron synchronization leading to coherent global perceptions. Synchronization implies a transitory control of neuron chaos. Depending on the time duration of this control, a cognitive agent has different amounts of awareness. Combining this with a stream of external inputs, one can point at an optimal use of internal resources, that is called cognitive creativity. While coherence is associated with long range correlations, complexity arises whenever an array of coupled dynamical systems displays multiple paths of coherence. What is the relation among the three concepts in the title? While coherence is associated with long range correlations, complexity arises whenever an array of coupled dynamical systems displays multiple paths of coherence. Creativity corresponds to a free selection of a coherence path within a complex nest. As sketched above, it seems dynamically related to chaos control.

  7. The Emparassment of Complexity

    NASA Astrophysics Data System (ADS)

    Nowotny, Helga

    My vision of complexity sciences targets their potential to extend the range, precision, and depth in making predictions. While this has always been the ambition and yardstick for the physicalmathematical sciences, complexity sciences now allow to include society and social behavior - to some extent. There is agreement that society is a complex adaptive system, CAS, with a few peculiarities. Ignoring, downplaying, or naturalizing them, i.e. to take them as essential and given, carries the risk to end up with abstractions which are cutoff from the dynamics of societal contexts. One of the peculiarities of society as a CAS is that the models with which we try to make sense of the world are invented and constructed by us. It is humans who make observations and provide the assumptions on which models are based. Humans leave traces that are collected and processed to be transformed into data. Humans decide to which purpose they will be put and how they will be repurposed. Humans are object of research and subject. Coping with these peculiarities requires an inbuilt reflexivity. Practioners must perform a double act and do so repeatedly. They must engage in a focused way with their scientific work and equally distance themselves by critically reflecting their often tacit assumptions. A friend of mine, Yehuda Elkana, called this twotier thinking...

  8. Emergent Complex Network Geometry

    PubMed Central

    Wu, Zhihao; Menichetti, Giulia; Rahmede, Christoph; Bianconi, Ginestra

    2015-01-01

    Networks are mathematical structures that are universally used to describe a large variety of complex systems such as the brain or the Internet. Characterizing the geometrical properties of these networks has become increasingly relevant for routing problems, inference and data mining. In real growing networks, topological, structural and geometrical properties emerge spontaneously from their dynamical rules. Nevertheless we still miss a model in which networks develop an emergent complex geometry. Here we show that a single two parameter network model, the growing geometrical network, can generate complex network geometries with non-trivial distribution of curvatures, combining exponential growth and small-world properties with finite spectral dimensionality. In one limit, the non-equilibrium dynamical rules of these networks can generate scale-free networks with clustering and communities, in another limit planar random geometries with non-trivial modularity. Finally we find that these properties of the geometrical growing networks are present in a large set of real networks describing biological, social and technological systems. PMID:25985280

  9. Keynes, Hayek and Complexity

    NASA Astrophysics Data System (ADS)

    Ormerod, Paul

    In the spirit of the overall topic of the conference, in this paper I consider the extent to which economic theory includes elements of the complex systems approach. I am setting to one side here the developments over the past decade in applying complex systems analysis to economic problems. This is not because this recent work is not important. It most certainly is. But I want to argue that there is a very distinct tradition of what we would now describe as a complex systems approach in the works of two of the greatest economists of the 20th century. There is of course a dominant intellectual paradigm within economics, that known as `neo-classical'economics. This paradigm is by no means an empty box, and is undoubtedly useful in helping to understand how some aspects of the social and economic worlds work. But even in its heyday, neo-classical economics never succeeded by its empirical success in driving out completely other theoretical approaches, for its success was simply not sufficient to do so. Much more importantly, economics over the past twenty or thirty years has become in an increasing state of flux.

  10. The Stigma Complex

    PubMed Central

    Pescosolido, Bernice A.; Martin, Jack K.

    2016-01-01

    Since the beginning of the twenty-first century, research on stigma has continued. Building on conceptual and empirical work, the recent period clarifies new types of stigmas, expansion of measures, identification of new directions, and increasingly complex levels. Standard beliefs have been challenged, the relationship between stigma research and public debates reconsidered, and new scientific foundations for policy and programs suggested. We begin with a summary of the most recent Annual Review articles on stigma, which reminded sociologists of conceptual tools, informed them of developments from academic neighbors, and claimed findings from the early period of “resurgence.” Continued (even accelerated) progress has also revealed a central problem. Terms and measures are often used interchangeably, leading to confusion and decreasing accumulated knowledge. Drawing from this work but focusing on the past 14 years of stigma research (including mental illness, sexual orientation, HIV/AIDS, and race/ethnicity), we provide a theoretical architecture of concepts (e.g., prejudice, experienced/received discrimination), drawn together through a stigma process (i.e., stigmatization), based on four theoretical premises. Many characteristics of the mark (e.g., discredited, concealable) and variants (i.e., stigma types and targets) become the focus of increasingly specific and multidimensional definitions. Drawing from complex and systems science, we propose a stigma complex, a system of interrelated, heterogeneous parts bringing together insights across disciplines to provide a more realistic and complicated sense of the challenge facing research and change efforts. The Framework Integrating Normative Influences on Stigma (FINIS) offers a multilevel approach that can be tailored to stigmatized statuses. Finally, we outline challenges for the next phase of stigma research, with the goal of continuing scientific activity that enhances our understanding of stigma and builds

  11. Complex-Valued Autoencoders

    PubMed Central

    Baldi, Pierre; Lu, Zhiqin

    2012-01-01

    Autoencoders are unsupervised machine learning circuits, with typically one hidden layer, whose learning goal is to minimize an average distortion measure between inputs and outputs. Linear autoencoders correspond to the special case where only linear transformations between visible and hidden variables are used. While linear autoencoders can be defined over any field, only real-valued linear autoencoders have been studied so far. Here we study complex-valued linear autoencoders where the components of the training vectors and adjustable matrices are defined over the complex field with the L2 norm. We provide simpler and more general proofs that unify the real-valued and complex-valued cases, showing that in both cases the landscape of the error function is invariant under certain groups of transformations. The landscape has no local minima, a family of global minima associated with Principal Component Analysis, and many families of saddle points associated with orthogonal projections onto sub-space spanned by sub-optimal subsets of eigenvectors of the covariance matrix. The theory yields several iterative, convergent, learning algorithms, a clear understanding of the generalization properties of the trained autoencoders, and can equally be applied to the hetero-associative case when external targets are provided. Partial results on deep architecture as well as the differential geometry of autoencoders are also presented. The general framework described here is useful to classify autoencoders and identify general properties that ought to be investigated for each class, illuminating some of the connections between autoencoders, unsupervised learning, clustering, Hebbian learning, and information theory. PMID:22622264

  12. AMPK in Yeast: The SNF1 (Sucrose Non-fermenting 1) Protein Kinase Complex.

    PubMed

    Sanz, Pascual; Viana, Rosa; Garcia-Gimeno, Maria Adelaida

    2016-01-01

    In yeast, SNF1 protein kinase is the orthologue of mammalian AMPK complex. It is a trimeric complex composed of Snf1 protein kinase (orthologue of AMPKα catalytic subunit), Snf4 (orthologue of AMPKγ regulatory subunit), and a member of the Gal83/Sip1/Sip2 family of proteins (orthologues of AMPKβ subunit) that act as scaffolds and also regulate the subcellular localization of the complex. In this chapter, we review the recent literature on the characteristics of SNF1 complex subunits, the structure and regulation of the activity of the SNF1 complex, its role at the level of transcriptional regulation of relevant target genes and also at the level of posttranslational modification of targeted substrates. We also review the crosstalk of SNF1 complex activity with other key protein kinase pathways such as cAMP-PKA, TORC1, and PAS kinase.

  13. Proteins : paradigms of complexity /

    SciTech Connect

    Frauenfelder, Hans,

    2001-01-01

    Proteins are the working machines of living systems. Directed by the DNA, of the order of a few hundred building blocks, selected from twenty different amino acids, are covalently linked into a linear polypeptide chain. In the proper environment, the chain folds into the working protein, often a globule of linear dimensions of a few nanometers. The biologist considers proteins units from which living systems are built. Many physical scientists look at them as systems in which the laws of complexity can be studied better than anywhere else. Some of the results of such studies will be sketched.

  14. Drying of Complex Suspensions

    NASA Astrophysics Data System (ADS)

    Xu, Lei; Bergès, Alexis; Lu, Peter J.; Studart, André R.; Schofield, Andrew B.; Oki, Hidekazu; Davies, Simon; Weitz, David A.

    2010-03-01

    We investigate the 3D structure and drying dynamics of complex mixtures of emulsion droplets and colloidal particles, using confocal microscopy. Air invades and rapidly collapses large emulsion droplets, forcing their contents into the surrounding porous particle pack at a rate proportional to the square of the droplet radius. By contrast, small droplets do not collapse, but remain intact and are merely deformed. A simple model coupling the Laplace pressure to Darcy’s law correctly estimates both the threshold radius separating these two behaviors, and the rate of large-droplet evacuation. Finally, we use these systems to make novel hierarchical structures.

  15. Physics and complexity

    PubMed Central

    Sherrington, David

    2010-01-01

    This paper is concerned with complex macroscopic behaviour arising in many-body systems through the combinations of competitive interactions and disorder, even with simple ingredients at the microscopic level. It attempts to indicate and illustrate the richness that has arisen, in conceptual understanding, in methodology and in application, across a large range of scientific disciplines, together with a hint of some of the further opportunities that remain to be tapped. In doing so, it takes the perspective of physics and tries to show, albeit rather briefly, how physics has contributed and been stimulated. PMID:20123753

  16. Complex regional pain syndrome

    PubMed Central

    Sebastin, Sandeep J

    2011-01-01

    Complex regional pain syndrome (CRPS) previously known as reflex sympathetic dystrophy is a chronic neurological disorder involving the limbs characterized by disabling pain, swelling, vasomotor instability, sudomotor abnormality, and impairment of motor function. CRPS is not uncommon after hand surgery and may complicate post-operative care. There is no specific diagnostic test for CRPS and the diagnosis is based on history, clinical examination, and supportive laboratory findings. Recent modifications to diagnostic criteria have enabled clinicians to diagnose this disease more consistently. This review gives a synopsis of CRPS and discusses the diagnosis, pathophysiology, and treatment options based on the limited evidence in the literature. PMID:22022040

  17. Organization of complex networks

    NASA Astrophysics Data System (ADS)

    Kitsak, Maksim

    Many large complex systems can be successfully analyzed using the language of graphs and networks. Interactions between the objects in a network are treated as links connecting nodes. This approach to understanding the structure of networks is an important step toward understanding the way corresponding complex systems function. Using the tools of statistical physics, we analyze the structure of networks as they are found in complex systems such as the Internet, the World Wide Web, and numerous industrial and social networks. In the first chapter we apply the concept of self-similarity to the study of transport properties in complex networks. Self-similar or fractal networks, unlike non-fractal networks, exhibit similarity on a range of scales. We find that these fractal networks have transport properties that differ from those of non-fractal networks. In non-fractal networks, transport flows primarily through the hubs. In fractal networks, the self-similar structure requires any transport to also flow through nodes that have only a few connections. We also study, in models and in real networks, the crossover from fractal to non-fractal networks that occurs when a small number of random interactions are added by means of scaling techniques. In the second chapter we use k-core techniques to study dynamic processes in networks. The k-core of a network is the network's largest component that, within itself, exhibits all nodes with at least k connections. We use this k-core analysis to estimate the relative leadership positions of firms in the Life Science (LS) and Information and Communication Technology (ICT) sectors of industry. We study the differences in the k-core structure between the LS and the ICT sectors. We find that the lead segment (highest k-core) of the LS sector, unlike that of the ICT sector, is remarkably stable over time: once a particular firm enters the lead segment, it is likely to remain there for many years. In the third chapter we study how

  18. Complexity, contingency, and criticality.

    PubMed Central

    Bak, P; Paczuski, M

    1995-01-01

    Complexity originates from the tendency of large dynamical systems to organize themselves into a critical state, with avalanches or "punctuations" of all sizes. In the critical state, events which would otherwise be uncoupled become correlated. The apparent, historical contingency in many sciences, including geology, biology, and economics, finds a natural interpretation as a self-organized critical phenomenon. These ideas are discussed in the context of simple mathematical models of sandpiles and biological evolution. Insights are gained not only from numerical simulations but also from rigorous mathematical analysis. Images Fig. 3 Fig. 4 PMID:11607561

  19. Chalcogenide centred gold complexes.

    PubMed

    Gimeno, M Concepción; Laguna, Antonio

    2008-09-01

    Chalcogenide-centred gold complexes are an important class of compounds in which a central chalcogen is surrounded by several gold atoms or gold and other metals. They have special characteristics such as unusual geometries, electron deficiency and properties such as luminescence or non-linear optical properties. The best known species are the trinuclear [E(AuPR3)3]+, 'oxonium' type species, that have high synthetic applicability, not only in other chalcogen-centred species, but in many other organometallic derivatives. The aurophilic interactions play an important role in the stability, preference for a particular geometry and luminescence properties in this type of derivatives (critical review, 117 references).

  20. Macroevolution of complex retroviruses.

    PubMed

    Katzourakis, Aris; Gifford, Robert J; Tristem, Michael; Gilbert, M Thomas P; Pybus, Oliver G

    2009-09-18

    Retroviruses can leave a "fossil record" in their hosts' genomes in the form of endogenous retroviruses. Foamy viruses, complex retroviruses that infect mammals, have been notably absent from this record. We have found an endogenous foamy virus within the genomes of sloths and show that foamy viruses were infecting mammals more than 100 million years ago and codiverged with their hosts across an entire geological era. Our analysis highlights the role of evolutionary constraint in maintaining viral genome structure and indicates that accessory genes and mammalian mechanisms of innate immunity are the products of macroevolutionary conflict played out over a geological time scale.

  1. Linking social complexity and vocal complexity: a parid perspective

    PubMed Central

    Krams, Indrikis; Krama, Tatjana; Freeberg, Todd M.; Kullberg, Cecilia; Lucas, Jeffrey R.

    2012-01-01

    The Paridae family (chickadees, tits and titmice) is an interesting avian group in that species vary in important aspects of their social structure and many species have large and complex vocal repertoires. For this reason, parids represent an important set of species for testing the social complexity hypothesis for vocal communication—the notion that as groups increase in social complexity, there is a need for increased vocal complexity. Here, we describe the hypothesis and some of the early evidence that supported the hypothesis. Next, we review literature on social complexity and on vocal complexity in parids, and describe some of the studies that have made explicit tests of the social complexity hypothesis in one parid—Carolina chickadees, Poecile carolinensis. We conclude with a discussion, primarily from a parid perspective, of the benefits and costs of grouping and of physiological factors that might mediate the relationship between social complexity and changes in signalling behaviour. PMID:22641826

  2. Linking social complexity and vocal complexity: a parid perspective.

    PubMed

    Krams, Indrikis; Krama, Tatjana; Freeberg, Todd M; Kullberg, Cecilia; Lucas, Jeffrey R

    2012-07-05

    The Paridae family (chickadees, tits and titmice) is an interesting avian group in that species vary in important aspects of their social structure and many species have large and complex vocal repertoires. For this reason, parids represent an important set of species for testing the social complexity hypothesis for vocal communication--the notion that as groups increase in social complexity, there is a need for increased vocal complexity. Here, we describe the hypothesis and some of the early evidence that supported the hypothesis. Next, we review literature on social complexity and on vocal complexity in parids, and describe some of the studies that have made explicit tests of the social complexity hypothesis in one parid--Carolina chickadees, Poecile carolinensis. We conclude with a discussion, primarily from a parid perspective, of the benefits and costs of grouping and of physiological factors that might mediate the relationship between social complexity and changes in signalling behaviour.

  3. Method for preparing radiopharmaceutical complexes

    DOEpatents

    Jones, Alun G.; Davison, Alan; Abrams, Michael J.

    1989-05-02

    A method for preparing radiopharmaceutical complexes that are substantially free of the reaction materials used to produce the radiopharmaceutical complex is disclosed. The method involves admixing in a suitable first solvent in a container a target seeking ligand or salt or metal adduct thereof, a radionuclide label, and a reducing agent for said radionuclide, thereby forming said radiopharmaceutical complex; coating the interior walls of the container with said pharmaceutical complex; discarding the solvent containing by-products and unreacted starting reaction materials; and removing the radiopharmaceutical complex from said walls by dissolving it in a second solvent, thereby obtaining said radiopharmaceutical complex substantially free of by-products and unreacted starting materials.

  4. Polyhydride complexes for hydrogen storage

    SciTech Connect

    Jensen, C.M.

    1995-09-01

    Polyhydride metal complexes are being developed for application in hydrogen storage. Efforts have focused on developing complexes with improved available hydrogen weight percentages. We have explored the possibility that complexes containing aromatic hydrocarbon ligands could store hydrogen at both the metal center and in the ligands. We have synthesized novel indenyl hydride complexes and explored their reactivity with hydrogen. The reversible hydrogenation of [IrH{sub 3}(PPh{sub 3})({eta}{sup 5}-C{sub 10}H{sub 7})]{sup +} has been achieved. While attempting to prepare {eta}{sup 6}-tetrahydronaphthalene complexes, we discovered that certain polyhydride complexes catalyze both the hydrogenation and dehydrogenation of tetrahydronaphthalene.

  5. Tuberous sclerosis complex.

    PubMed

    Henske, Elizabeth P; Jóźwiak, Sergiusz; Kingswood, J Christopher; Sampson, Julian R; Thiele, Elizabeth A

    2016-05-26

    Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems and is caused by loss-of-function mutations in one of two genes: TSC1 or TSC2. The disorder can affect both adults and children. First described in depth by Bourneville in 1880, it is now estimated that nearly 2 million people are affected by the disease worldwide. The clinical features of TSC are distinctive and can vary widely between individuals, even within one family. Major features of the disease include tumours of the brain, skin, heart, lungs and kidneys, seizures and TSC-associated neuropsychiatric disorders, which can include autism spectrum disorder and cognitive disability. TSC1 (also known as hamartin) and TSC2 (also known as tuberin) form the TSC protein complex that acts as an inhibitor of the mechanistic target of rapamycin (mTOR) signalling pathway, which in turn plays a pivotal part in regulating cell growth, proliferation, autophagy and protein and lipid synthesis. Remarkable progress in basic and translational research, in addition to several randomized controlled trials worldwide, has led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas and pulmonary lymphangioleiomyomatosis, but further research is needed to establish full indications of therapeutic treatment. In this Primer, we review the state-of-the-art knowledge in the TSC field, including the molecular and cellular basis of the disease, medical management, major knowledge gaps and ongoing research towards a cure.

  6. Complex Semantic Networks

    NASA Astrophysics Data System (ADS)

    Teixeira, G. M.; Aguiar, M. S. F.; Carvalho, C. F.; Dantas, D. R.; Cunha, M. V.; Morais, J. H. M.; Pereira, H. B. B.; Miranda, J. G. V.

    Verbal language is a dynamic mental process. Ideas emerge by means of the selection of words from subjective and individual characteristics throughout the oral discourse. The goal of this work is to characterize the complex network of word associations that emerge from an oral discourse from a discourse topic. Because of that, concepts of associative incidence and fidelity have been elaborated and represented the probability of occurrence of pairs of words in the same sentence in the whole oral discourse. Semantic network of words associations were constructed, where the words are represented as nodes and the edges are created when the incidence-fidelity index between pairs of words exceeds a numerical limit (0.001). Twelve oral discourses were studied. The networks generated from these oral discourses present a typical behavior of complex networks and their indices were calculated and their topologies characterized. The indices of these networks obtained from each incidence-fidelity limit exhibit a critical value in which the semantic network has maximum conceptual information and minimum residual associations. Semantic networks generated by this incidence-fidelity limit depict a pattern of hierarchical classes that represent the different contexts used in the oral discourse.

  7. Complexity in language acquisition.

    PubMed

    Clark, Alexander; Lappin, Shalom

    2013-01-01

    Learning theory has frequently been applied to language acquisition, but discussion has largely focused on information theoretic problems-in particular on the absence of direct negative evidence. Such arguments typically neglect the probabilistic nature of cognition and learning in general. We argue first that these arguments, and analyses based on them, suffer from a major flaw: they systematically conflate the hypothesis class and the learnable concept class. As a result, they do not allow one to draw significant conclusions about the learner. Second, we claim that the real problem for language learning is the computational complexity of constructing a hypothesis from input data. Studying this problem allows for a more direct approach to the object of study--the language acquisition device-rather than the learnable class of languages, which is epiphenomenal and possibly hard to characterize. The learnability results informed by complexity studies are much more insightful. They strongly suggest that target grammars need to be objective, in the sense that the primitive elements of these grammars are based on objectively definable properties of the language itself. These considerations support the view that language acquisition proceeds primarily through data-driven learning of some form. Copyright © 2013 Cognitive Science Society, Inc.

  8. The authority of complexity.

    PubMed

    Stehr, N; Grundmann, R

    2001-06-01

    The assertion about the unique 'complexity' or the peculiarly intricate character of social phenomena has, at least within sociology, a long, venerable and virtually uncontested tradition. At the turn of the last century, classical social theorists, for example, Georg Simmel and Emile Durkheim, made prominent and repeated reference to this attribute of the subject matter of sociology and the degree to which it complicates, even inhibits the develop and application of social scientific knowledge. Our paper explores the origins, the basis and the consequences of this assertion and asks in particular whether the classic complexity assertion still deserves to be invoked in analyses that ask about the production and the utilization of social scientific knowledge in modern society. We present John Maynard Keynes' economic theory and its practical applications as an illustration. We conclude that the practical value of social scientific knowledge is not dependent on a faithful, in the sense of complete, representation of social reality. Instead, social scientific knowledge that wants to optimize its practicality has to attend and attach itself to elements of social situations that can be altered or are actionable.

  9. Tuberous sclerosis complex.

    PubMed

    Islam, Monica P; Roach, E Steve

    2015-01-01

    Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome that can affect the brain, skin, eyes, kidneys, heart, and lungs. TSC alters cellular proliferation and differentiation, resulting in hamartomas of various organs, tumor formation, and altered neuronal migration. The phenotype is highly variable. Most individuals have seizures, commonly including infantile spasms, and there is variable intellectual disability and autism. Neonates can present with cardiac failure due to intracardiac rhabdomyomas. The likelihood of renal angiomyolipomas increases with age, and renal disease is the most common cause of death in adults with TSC. Pulmonary involvement occurs predominantly in women and carries a high morbidity and mortality. TSC is inherited as an autosomal dominant trait, but spontaneous mutations are common. A mutation of either TSC1 on chromosome 9 or TSC2 on chromosome 16 leads to dysfunction of hamartin or tuberin, respectively. These two proteins form a functional complex that modulates the mammalian target of rapamycin (mTOR) pathway. Medications that inhibit mTOR are being used to treat TSC-related tumors, and current studies are investigating whether these agents could alleviate other TSC complications. Consensus statements guide identification and optimal management of many of the TSC-related complications at diagnosis and throughout the lifespan. A multidisciplinary approach is necessary for optimal management of individuals with TSC.

  10. Dislocations in complex materials.

    PubMed

    Chisholm, Matthew F; Kumar, Sharvan; Hazzledine, Peter

    2005-02-04

    Deformation of metals and alloys by dislocations gliding between well-separated slip planes is a well-understood process, but most crystal structures do not possess such simple geometric arrangements. Examples are the Laves phases, the most common class of intermetallic compounds and exist with ordered cubic, hexagonal, and rhombohedral structures. These compounds are usually brittle at low temperatures, and transformation from one structure to another is slow. On the basis of geometric and energetic considerations, a dislocation-based mechanism consisting of two shears in different directions on adjacent atomic planes has been used to explain both deformation and phase transformations in this class of materials. We report direct observations made by Z-contrast atomic resolution microscopy of stacking faults and dislocation cores in the Laves phase Cr2Hf. These results show that this complex dislocation scheme does indeed operate in this material. Knowledge gained of the dislocation core structure will enable improved understanding of deformation mechanisms and phase transformation kinetics in this and other complex structures.

  11. Complex master slave interferometry.

    PubMed

    Rivet, Sylvain; Maria, Michael; Bradu, Adrian; Feuchter, Thomas; Leick, Lasse; Podoleanu, Adrian

    2016-02-08

    A general theoretical model is developed to improve the novel Spectral Domain Interferometry method denoted as Master/Slave (MS) Interferometry. In this model, two functions, g and h are introduced to describe the modulation chirp of the channeled spectrum signal due to nonlinearities in the decoding process from wavenumber to time and due to dispersion in the interferometer. The utilization of these two functions brings two major improvements to previous implementations of the MS method. A first improvement consists in reducing the number of channeled spectra necessary to be collected at Master stage. In previous MSI implementation, the number of channeled spectra at the Master stage equated the number of depths where information was selected from at the Slave stage. The paper demonstrates that two experimental channeled spectra only acquired at Master stage suffice to produce A-scans from any number of resolved depths at the Slave stage. A second improvement is the utilization of complex signal processing. Previous MSI implementations discarded the phase. Complex processing of the electrical signal determined by the channeled spectrum allows phase processing that opens several novel avenues. A first consequence of such signal processing is reduction in the random component of the phase without affecting the axial resolution. In previous MSI implementations, phase instabilities were reduced by an average over the wavenumber that led to reduction in the axial resolution.

  12. Growth of Complex Organizations

    NASA Astrophysics Data System (ADS)

    Nunes Amaral, Luis A.

    2000-03-01

    We analyze a database comprising all publicly-traded US firms within the years 1974--93(M.H.R. Stanley et al.), Nature 379, 804 (1996); L.A.N. Amaral et al., J. Phys. (France) I 7, 621 (1997). We find (i) that the distribution of the annual growth rates ---for companies with approximately the same size S--- decays as an exponential, and (ii) that the standard deviation σ of these distributions scales as σ ~ S^-β. We introduce a dynamical model in which we assume that each firm has a complex internal structure comprising many subunits(L.A.N. Amaral et al.), Phys. Rev. Lett. 80, 1385 (1998). We study the case in which (i) each subunit grows in a multiplicative manner, and (ii) the interactions between the firms are mean field. We find agreement between our predictions and the empirical results for firms. We then analyze the fluctuations in the gross domestic product of 152 countries for the period 1950--92 and find a surprising agreement with the results for firm growth (Y. Lee et al.), Phys. Rev. Lett. 81, 3275 (1998). Finally, we analyze the fluctuations in the research output and research input of US universities and find sinilar scaling laws(V. Plerou et al.), Nature 400, 433 (1999). Our empirical results and model suggest that the growth of organizations with complex structure are governed by similar mechanisms.

  13. Complex attentional control settings.

    PubMed

    Parrott, Stacey E; Levinthal, Brian R; Franconeri, Steven L

    2010-12-01

    The visual system prioritizes information through a variety of mechanisms, including "attentional control settings" that specify features (e.g., colour) that are relevant to current goals. Recent work shows that these control settings may be more complex than previously thought, such that participants can monitor for independent features at different locations (Adamo, Pun, Pratt, & Ferber, 2008). However, this result leaves unclear whether these control settings affect early attentional selection or later target processing. We dissociated between these possibilities in two ways. In Experiment 1, participants were asked to determine whether a target object, which was preceded by an uninformative cue, matched one of two target templates (e.g., a blue vertical object or a green horizontal object). Participants monitored for independent features in the same location, but in different objects, which should reduce the effectiveness of the control setting if it is due to early attentional selection, but not if it is due to later target processing. In Experiment 2, we removed the ability of the cue to prime the target identity, which makes the opposite prediction. Together, the results suggest that complex attentional control settings primarily affect later target identity processing, and not early attentional selection.

  14. Not so Complex: Iteration in the Complex Plane

    ERIC Educational Resources Information Center

    O'Dell, Robin S.

    2014-01-01

    The simple process of iteration can produce complex and beautiful figures. In this article, Robin O'Dell presents a set of tasks requiring students to use the geometric interpretation of complex number multiplication to construct linear iteration rules. When the outputs are plotted in the complex plane, the graphs trace pleasing designs…

  15. Syntactic Complexity as an Aspect of Text Complexity

    ERIC Educational Resources Information Center

    Frantz, Roger S.; Starr, Laura E.; Bailey, Alison L.

    2015-01-01

    Students' ability to read complex texts is emphasized in the Common Core State Standards (CCSS) for English Language Arts and Literacy. The standards propose a three-part model for measuring text complexity. Although the model presents a robust means for determining text complexity based on a variety of features inherent to a text as well as…

  16. Not so Complex: Iteration in the Complex Plane

    ERIC Educational Resources Information Center

    O'Dell, Robin S.

    2014-01-01

    The simple process of iteration can produce complex and beautiful figures. In this article, Robin O'Dell presents a set of tasks requiring students to use the geometric interpretation of complex number multiplication to construct linear iteration rules. When the outputs are plotted in the complex plane, the graphs trace pleasing designs…

  17. Syntactic Complexity as an Aspect of Text Complexity

    ERIC Educational Resources Information Center

    Frantz, Roger S.; Starr, Laura E.; Bailey, Alison L.

    2015-01-01

    Students' ability to read complex texts is emphasized in the Common Core State Standards (CCSS) for English Language Arts and Literacy. The standards propose a three-part model for measuring text complexity. Although the model presents a robust means for determining text complexity based on a variety of features inherent to a text as well as…

  18. Nuclear Weapons Complex reconfiguration study

    SciTech Connect

    Not Available

    1991-01-01

    Shortly after assuming duties as Secretary of Energy, I reviewed the Nuclear Weapons Complex Modernization Report'' submitted to the Congress in January 1989 as required by the National Defense Authorization Act of 1988 and 1989. My review showed that several of the report's assumptions needed to be re-evaluated. During this eighteen-month review, dramatic world changes forced further reassessments of the future Nuclear Weapons Complex. These changes are reflected in the new report. The new report presents a plan to achieve a reconfigured complex, called Complex-21. Complex-21 would be smaller, less diverse, and less expensive to operated than the Complex of today. Complex-21 would be able to safely and reliability support nuclear deterrent stockpile objectives set forth by the President and funded by the Congress. It would be consistent with realities of the emerging international security environment and flexible enough to accommodate the likely range of deterrent contingencies. In addition, Complex-21 would be constructed and operated to comply with all applicable federal, state, and local laws, regulations, and orders. Achieving Complex-21 will require significant resources. This report provides and organized approach toward selecting the most appropriate configuration for Complex-21, satisfying environmental requirements, and minimizing costs. The alternative -- to continue to use piecemeal fixes to run an antiquated complex -- will be more expensive and provide a less reliable Nuclear Weapons Complex. As a consequence, implementation of the Complex-21 plan is considered necessary to ensure continued viability of our nuclear deterrent.

  19. Complexity in scalable computing.

    SciTech Connect

    Rouson, Damian W. I.

    2008-12-01

    The rich history of scalable computing research owes much to a rapid rise in computing platform scale in terms of size and speed. As platforms evolve, so must algorithms and the software expressions of those algorithms. Unbridled growth in scale inevitably leads to complexity. This special issue grapples with two facets of this complexity: scalable execution and scalable development. The former results from efficient programming of novel hardware with increasing numbers of processing units (e.g., cores, processors, threads or processes). The latter results from efficient development of robust, flexible software with increasing numbers of programming units (e.g., procedures, classes, components or developers). The progression in the above two parenthetical lists goes from the lowest levels of abstraction (hardware) to the highest (people). This issue's theme encompasses this entire spectrum. The lead author of each article resides in the Scalable Computing Research and Development Department at Sandia National Laboratories in Livermore, CA. Their co-authors hail from other parts of Sandia, other national laboratories and academia. Their research sponsors include several programs within the Department of Energy's Office of Advanced Scientific Computing Research and its National Nuclear Security Administration, along with Sandia's Laboratory Directed Research and Development program and the Office of Naval Research. The breadth of interests of these authors and their customers reflects in the breadth of applications this issue covers. This article demonstrates how to obtain scalable execution on the increasingly dominant high-performance computing platform: a Linux cluster with multicore chips. The authors describe how deep memory hierarchies necessitate reducing communication overhead by using threads to exploit shared register and cache memory. On a matrix-matrix multiplication problem, they achieve up to 96% parallel efficiency with a three-part strategy: intra

  20. Amphotericin B Lipid Complex Injection

    MedlinePlus

    Amphotericin B lipid complex injection is used to treat serious, possibly life-threatening fungal infections in people who did not respond ... to tolerate conventional amphotericin B therapy. Amphotericin B lipid complex injection is in a class of medications ...

  1. Complex pendulum biomass sensor

    SciTech Connect

    Hoskinson, Reed L.; Kenney, Kevin L.; Perrenoud, Ben C.

    2007-12-25

    A complex pendulum system biomass sensor having a plurality of pendulums. The plurality of pendulums allow the system to detect a biomass height and density. Each pendulum has an angular deflection sensor and a deflector at a unique height. The pendulums are passed through the biomass and readings from the angular deflection sensors are fed into a control system. The control system determines whether adjustment of machine settings is appropriate and either displays an output to the operator, or adjusts automatically adjusts the machine settings, such as the speed, at which the pendulums are passed through the biomass. In an alternate embodiment, an entanglement sensor is also passed through the biomass to determine the amount of biomass entanglement. This measure of entanglement is also fed into the control system.

  2. Understanding complex chiral plasmonics.

    PubMed

    Duan, Xiaoyang; Yue, Song; Liu, Na

    2015-11-07

    Chiral nanoplasmonics exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response within nanoscale metallic structures. Recently, a number of different approaches have been utilized to create chiral nanoplasmonic structures. However, particularly for tailoring nanooptical chiral sensing devices, the understanding of the resulting chiroptical response when coupling chiral and achiral structures together is crucial and has not been completely understood to date. Here, we present a thorough and step-by-step experimental study to understand the intriguing chiral-achiral coupling scheme. We set up a hybrid plasmonic system, which bears resemblance to the 'host-guest' system in supramolecular chemistry to analyze and explain the complex chiral response both at the chiral and achiral plasmonic resonances. We also provide an elegant and simple analytical model, which can describe, predict, and comprehend the chiroptical spectra in detail. Our study will shed light on designing well-controlled chiral-achiral coupling platforms for reliable chiral sensing.

  3. Complexity, Metastability and Nonextensivity

    NASA Astrophysics Data System (ADS)

    Beck, C.; Benedek, G.; Rapisarda, A.; Tsallis, C.

    Work and heat fluctuations in systems with deterministic and stochastic forces / E. G. D. Cohen and R. Van Zon -- Is the entropy S[symbol] extensive or nonextensive? / C. Tsallis -- Superstatistics: recent developments and applications / C. Beck -- Two stories outside Boltzmann-Gibbs statistics: Mori's Q-phase transitions and glassy dynamics at the onset of chaos / A. Robledo, F. Baldovin and E. Mayoral -- Time-averages and the heat theorem / A. Carati -- Fundamental formulae and numerical evidences for the central limit theorem in Tsallis statistics / H. Suyari -- Generalizing the Planck distribution / A. M. C. Soma and C. Tsallis -- The physical roots of complexity: renewal or modulation? / P. Grigolini -- Nonequivalent ensembles and metastability / H. Touchette and R. S. Ellis -- Statistical physics for cosmic structures / L. Pietronero and F. Sylos Labini -- Metastability and anomalous behavior in the HMF model: connections to nonextensive thermodynamics and glassy dynamics / A. Pluchino, A. Rapisarda and V. Latora -- Vlasov analysis of relaxation and meta-equilibrium / C. Anteneodo and R. O. Vallejos -- Weak chaos in large conservative systems - infinite-range coupled standard maps / L. G. Moyano, A. P. Majtey and C. Tsallis -- Deterministc aging / E. Barkai -- Edge of chaos of the classical kicked top map: sensitivity to initial conditions / S. M. Duarte Queirós and C. Tsallis -- What entropy at the edge of chaos? / M. Lissia, M. Coraddu and R. Tonelli -- Fractal growth of carbon schwarzites / G. Benedek ... [et al.] -- Clustering and interface propagation in interacting particle dynamics / A. Provata and V. K. Noussiou -- Resonant activation and noise enhanced stability in Josephson junctions / A. L. Pankratov and B. Spagnolo -- Symmetry breaking induced directed motions / C.-H. Chang and T. Y. Tsong -- General theory of Galilean-invariant entropic lattic Boltzmann models / B. M. Boghosian -- Unifying approach to the jamming transition in granular media and

  4. Complex Dark Matter

    ScienceCinema

    Lincoln, Don

    2016-07-12

    After a century of study, scientists have come to the realization that the ordinary matter made of atoms is a minority in the universe. In order to explain observations, it appears that there exists a new and undiscovered kind of matter, called dark matter, that is five times more prevalent than ordinary matter. The evidence for this new matter’s existence is very strong, but scientists know only a little about its nature. In today’s video, Fermilab’s Dr. Don Lincoln talks about an exciting and unconventional idea, specifically that dark matter might have a very complex set of structures and interactions. While this idea is entirely speculative, it is an interesting hypothesis and one that scientists are investigating.

  5. Complex Dark Matter

    SciTech Connect

    Lincoln, Don

    2015-04-16

    After a century of study, scientists have come to the realization that the ordinary matter made of atoms is a minority in the universe. In order to explain observations, it appears that there exists a new and undiscovered kind of matter, called dark matter, that is five times more prevalent than ordinary matter. The evidence for this new matter’s existence is very strong, but scientists know only a little about its nature. In today’s video, Fermilab’s Dr. Don Lincoln talks about an exciting and unconventional idea, specifically that dark matter might have a very complex set of structures and interactions. While this idea is entirely speculative, it is an interesting hypothesis and one that scientists are investigating.

  6. Recognizing complex patterns.

    PubMed

    Sinha, Pawan

    2002-11-01

    How the brain recognizes complex patterns in the environment is a central, but little understood question in neuroscience. The problem is of great significance for a host of applications such as biometric-based access control, autonomous robots and content-based information management. Although some headway in these directions has been made, the current artificial systems do not match the robustness and versatility of their biological counterparts. Here I examine recognition tasks drawn from two different sensory modalities--face recognition and speaker/speech recognition. The goal is to characterize the present state of artificial recognition technologies for these tasks, the influence of neuroscience on the design of these systems and the key challenges they face.

  7. The tuberous sclerosis complex

    PubMed Central

    Orlova, Ksenia A.; Crino, Peter B.

    2010-01-01

    Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that results from mutations in the TSC1 or TSC2 genes and is associated with hamartoma formation in multiple organ systems. The neurological manifestations of TSC are particularly challenging and include infantile spasms, intractable epilepsy, cognitive disabilities, and autism. Progress over the past 15 years has demonstrated that the TSC1 or TSC2 encoded proteins modulate cell function via the mTOR signaling cascade and serve as keystones in regulating cell growth and proliferation. The mTOR pathway provides an intersection for an intricate network of protein cascades that respond to cellular nutrition, energy levels, and growth-factor stimulation. In the brain, TSC1 and TSC2 have been implicated in cell body size, dendritic arborization, axonal outgrowth and targeting, neuronal migration, cortical lamination, and spine formation. Antagonism of the mTOR pathway with rapamycin and related compounds may provide new therapeutic options for TSC patients. PMID:20146692

  8. Complex regional pain syndrome

    PubMed Central

    Carr, Emily S.; De La Cerda, Ashley

    2016-01-01

    Complex regional pain syndrome (CRPS) is a neurologic disorder that often results in debilitating chronic pain, but the diagnosis may elude providers as it is one of exclusion. A history of trauma may be elucidated. We report a case of CRPS and review the clinical findings, appropriate workup, and treatment options for the patient. The patient we describe went through an extensive workup before receiving the correct diagnosis. Delay in diagnosis leads to prolonged suffering for the patient and, at times, unnecessary invasive debridement procedures. Raising awareness of this entity may help physicians make the correct diagnosis early, as well as initiate a collaborative effort between neurology, anesthesiology, and dermatology to provide the patient the most favorable outcome. PMID:27365892

  9. Managing Complex Medication Regimens.

    PubMed

    Harvath, Theresa A; Lindauer, Allison; Sexson, Kathryn

    2017-05-01

    : This article is the first in a series, Supporting Family Caregivers: No Longer Home Alone, published in collaboration with the AARP Public Policy Institute. Results of focus groups conducted as part of the AARP Public Policy Institute's No Longer Home Alone video project supported evidence that family caregivers aren't being given the information they need to manage the complex care regimens of their family members. This series of articles and accompanying videos aims to help nurses provide caregivers with the tools they need to manage their family member's medications. Each article explains the principles nurses should consider and reinforce with caregivers and is accompanied by a video for the caregiver to watch. The first video can be accessed at http://links.lww.com/AJN/A74.

  10. Evolution of Biological Complexity

    NASA Astrophysics Data System (ADS)

    Goldstein, Raymond E.

    It is a general rule of nature that larger organisms are more complex, at least as measured by the number of distinct types of cells present. This reflects the fitness advantage conferred by a division of labor among specialized cells over homogeneous totipotency. Yet, increasing size has both costs and benefits, and the search for understanding the driving forces behind the evolution of multicellularity is becoming a very active area of research. This article presents an overview of recent experimental and theoretical work aimed at understanding this biological problem from the perspective of physics. For a class of model organisms, the Volvocine green algae, an emerging hypothesis connects the transition from organisms with totipotent cells to those with terminal germ-soma differentiation to the competition between diffusion and fluid advection created by beating flagella. A number of challenging problems in fluid dynamics, nonlinear dynamics, and control theory emerge when one probes the workings of the simplest multicellular organisms.

  11. Divergences in holographic complexity

    NASA Astrophysics Data System (ADS)

    Reynolds, Alan; Ross, Simon F.

    2017-05-01

    We study the UV divergences in the action of the ‘Wheeler-de Witt patch’ in asymptotically AdS spacetimes, which has been conjectured to be dual to the computational complexity of the state of the dual field theory on a spatial slice of the boundary. We show that including a surface term in the action on the null boundaries which ensures invariance under coordinate transformations has the additional virtue of removing a stronger than expected divergence, making the leading divergence proportional to the proper volume of the boundary spatial slice. We compare the divergences in the action to divergences in the volume of a maximal spatial slice in the bulk, finding that the qualitative structure is the same, but subleading divergences have different relative coefficients in the two cases.

  12. Complex Tectonism on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Complex tectonism is evident in these images of Ganymede's surface. The solid state imaging camera on NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. The 80 kilometer (50 mile) wide lens-shaped feature in the center of the image is located at 32 degrees latitude and 188 degrees longitude along the border of a region of ancient dark terrain known as Marius Regio, and is near an area of younger bright terrain named Nippur Sulcus. The tectonism that created the structures in the bright terrain nearby has strongly affected the local dark terrain to form unusual structures such as the one shown here. The lens-like appearance of this feature is probably due to shearing of the surface, where areas have slid past each other and also rotated slightly. Note that in several places in these images, especially around the border of the lens-shaped feature, bright ridges appear to turn into dark grooves. Analysis of the geologic structures in areas like this are helping scientists to understand the complex tectonic history of Ganymede.

    North is to the top-left of the image, and the sun illuminates the surface from the southeast. The image covers an area about 63 kilometers (39 miles) by 120 kilometers (75 miles) across at a resolution of 188 meters (627 feet) per picture element. The images were taken on September 6, 1996 at a range of 18,522 kilometers (11,576 miles) by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  13. Complex Tectonism on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Complex tectonism is evident in these images of Ganymede's surface. The solid state imaging camera on NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. The 80 kilometer (50 mile) wide lens-shaped feature in the center of the image is located at 32 degrees latitude and 188 degrees longitude along the border of a region of ancient dark terrain known as Marius Regio, and is near an area of younger bright terrain named Nippur Sulcus. The tectonism that created the structures in the bright terrain nearby has strongly affected the local dark terrain to form unusual structures such as the one shown here. The lens-like appearance of this feature is probably due to shearing of the surface, where areas have slid past each other and also rotated slightly. Note that in several places in these images, especially around the border of the lens-shaped feature, bright ridges appear to turn into dark grooves. Analysis of the geologic structures in areas like this are helping scientists to understand the complex tectonic history of Ganymede.

    North is to the top-left of the image, and the sun illuminates the surface from the southeast. The image covers an area about 63 kilometers (39 miles) by 120 kilometers (75 miles) across at a resolution of 188 meters (627 feet) per picture element. The images were taken on September 6, 1996 at a range of 18,522 kilometers (11,576 miles) by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  14. The Complex Cepstrum - Revisited

    NASA Astrophysics Data System (ADS)

    Kemerait, R. C., Sr.

    2016-12-01

    Since this paper comes at the twilight of my career, it is appropriate to share my views on a subject very dear to my heart and to my long career. In 2004 "From Frequency to Quefrency: A History of the Cepstrum" was published in the IEEE Signal Processing magazine. There is no question that the authors, Alan V. Oppenheim and Ronald W. Schafer, were pioneers in this area of research, and this publication documents their involvement quite nicely. In parallel research also performed in the 1960's, Childers, et. al., renamed the original "Cepstrum" to the "Power Cepstrum" to avoid confusion with the principal topic of their research, that being the "Complex Cepstrum." The term "Power Cepstrum" has become widely used in the literature since that time. The Childers team, including Dr. Kemerait, published a summary of their work, as of that date, in the IEEE Proceedings of October 1977, and titled the article "The Cepstrum: A Guide to Processing." In the subsequent 40 years, Dr. Kemerait has continued to research cepstral techniques applied to many diverse problems; however, his primary research has been on estimating the depth of underground and underwater events. He has also applied these techniques to biomedical data: EEG, EKG, and Visua-evoked responses as well as on hydroacoustic data ; thereby, determining the "bubble pulse frequency", and the depths of the explosion and the ocean depth at the explosion point. He has also used cepstral techniques in the processing of ground penetrating radar, speech, machine diagnostics, and, throughout these years, seismic data. This paper emphasizes his recent improvements in processing primarily seismic and infrasound data associated with nuclear treaty monitoring. The emphasis is mainly on the recent improvements and the automation of the Complex Cepstrum process.

  15. The Ethical Complexity of Collaboration.

    ERIC Educational Resources Information Center

    Trzyna, Thomas; Batschelet, Margaret

    1990-01-01

    Argues that classroom collaboration is complex, perhaps more complex than collaboration in industry; students need to be trained in leadership and group dynamics and to be informed about the ethical complexity of their task; and instructors must make their expectations clear and state their standards for assessing a group's performance. (SR)

  16. Fragment-Based NMR Study of the Conformational Dynamics in the bHLH Transcription Factor Ascl1.

    PubMed

    Baronti, Lorenzo; Hošek, Tomáš; Gil-Caballero, Sergio; Raveh-Amit, Hadas; Calçada, Eduardo O; Ayala, Isabel; Dinnyés, András; Felli, Isabella C; Pierattelli, Roberta; Brutscher, Bernhard

    2017-04-11

    The Achaete-scute homolog 1 (Ascl1) protein regulates a large subset of genes that leads neuronal progenitor cells to distinctive differentiation pathways during human brain development. Although it is well known that Ascl1 binds DNA as a homo- or heterodimer via its basic helix-loop-helix (bHLH) motif, little is known about the conformational sampling properties of the DNA-free full-length protein, and in particular about the bHLH domain-flanking N- and C-terminal segments, which are predicted to be highly disordered in solution. The structural heterogeneity, low solubility, and high aggregation propensity of Ascl1 in aqueous buffer solutions make high-resolution studies of this protein a challenging task. Here, we have adopted a fragment-based strategy that allowed us to obtain high-quality NMR data providing, to our knowledge, the first comprehensive high-resolution information on the structural propensities and conformational dynamics of Ascl1. The emerging picture is that of an overall extended and highly dynamic polypeptide chain comprising three helical segments and lacking persistent long-range interactions. We also show that the C-terminal helix of the bHLH domain is involved in intermolecular interactions, even in the absence of DNA. Our results contribute to a better understanding of the mechanisms of action that govern the regulation of proneural transcription factors. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  17. Expression of a MyoD family member prefigures muscle pattern in Drosophila embryos.

    PubMed

    Michelson, A M; Abmayr, S M; Bate, M; Arias, A M; Maniatis, T

    1990-12-01

    We have isolated a Drosophila gene that is expressed in a temporal and spatial pattern during embryogenesis, strongly suggesting an important role for this gene in the early development of muscle. This gene, which we have named nautilus (nau), encodes basic and helix-loop-helix domains that display striking sequence similarity to those of the vertebrate myogenic regulatory gene family. nau transcripts are initially localized to segmentally repeated clusters of mesodermal cells, a pattern that is reminiscent of the expression of the achaete-scute genes in the Drosophila peripheral nervous system. These early nau-positive cells are detected just prior to the first morphological evidence of muscle cell fusion and occupy similar positions as the later-appearing muscle precursors. Subsequently, nau transcripts are present in at least a subset of growing muscle precursors and mature muscle fibers that exhibit distinct segmental differences. These observations establish nau as the earliest known marker of myogenesis in Drosophila and indicate that this gene may be a key determinant of pattern formation in the embryonic mesoderm.

  18. Phosphofructokinase-1 Negatively Regulates Neurogenesis from Neural Stem Cells.

    PubMed

    Zhang, Fengyun; Qian, Xiaodan; Qin, Cheng; Lin, Yuhui; Wu, Haiyin; Chang, Lei; Luo, Chunxia; Zhu, Dongya

    2016-06-01

    Phosphofructokinase-1 (PFK-1), a major regulatory glycolytic enzyme, has been implicated in the functions of astrocytes and neurons. Here, we report that PFK-1 negatively regulates neurogenesis from neural stem cells (NSCs) by targeting pro-neural transcriptional factors. Using in vitro assays, we found that PFK-1 knockdown enhanced, and PFK-1 overexpression inhibited the neuronal differentiation of NSCs, which was consistent with the findings from NSCs subjected to 5 h of hypoxia. Meanwhile, the neurogenesis induced by PFK-1 knockdown was attributed to the increased proliferation of neural progenitors and the commitment of NSCs to the neuronal lineage. Similarly, in vivo knockdown of PFK-1 also increased neurogenesis in the dentate gyrus of the hippocampus. Finally, we demonstrated that the neurogenesis mediated by PFK-1 was likely achieved by targeting mammalian achaete-scute homologue-1 (Mash 1), neuronal differentiation factor (NeuroD), and sex-determining region Y (SRY)-related HMG box 2 (Sox2). All together, our results reveal PFK-1 as an important regulator of neurogenesis.

  19. SDF-1/CXCR4 Signaling Maintains Stemness Signature in Mouse Neural Stem/Progenitor Cells

    PubMed Central

    Ling, Thai-Yen; Lin, Hsing-Yu; Liou, Jeffrey Tsai-Jui; Liu, Fei-Chih; Chen, I-Chun; Lee, Sue-Wei; Hsu, Yu

    2017-01-01

    SDF-1 and its primary receptor, CXCR4, are highly expressed in the embryonic central nervous system (CNS) and play a crucial role in brain architecture. Loss of SDF-1/CXCR4 signaling causes abnormal development of neural stem/progenitor cells (NSCs/NPCs) in the cerebellum, hippocampus, and cortex. However, the mechanism of SDF-1/CXCR4 axis in NSCs/NPCs regulation remains unknown. In this study, we found that elimination of SDF-1/CXCR4 transduction caused NSCs/NPCs to lose their stemness characteristics and to encounter neurogenic differentiation. Moreover, Notch and RE1 silencing transcription factor (REST) both play an essential role in NSCs/NPCs maintenance and neuronal differentiation and were dramatically downregulated following SDF-1/CXCR4 cascade inhibition. Finally, we demonstrated that the expression of achaete-scute homolog 1 (Ascl1), a proneural gene, and p27, an antiproliferative gene, were significantly increased after genetic elimination of SDF-1 alleles. Our results support that the loss of functional SDF-1/CXCR4 signaling pathway in NSCs/NPCs induces exit of cell cycle and promotes premature neural differentiation. PMID:28408934

  20. Ascl1 promotes tangential migration and confines migratory routes by induction of Ephb2 in the telencephalon

    PubMed Central

    Liu, Yuan-Hsuan; Tsai, Jin-Wu; Chen, Jia-Long; Yang, Wan-Shan; Chang, Pei-Ching; Cheng, Pei-Lin; Turner, David L.; Yanagawa, Yuchio; Wang, Tsu-Wei; Yu, Jenn-Yah

    2017-01-01

    During development, cortical interneurons generated from the ventral telencephalon migrate tangentially into the dorsal telencephalon. Although Achaete-scute family bHLH transcription factor 1 (Ascl1) plays important roles in the developing telencephalon, whether Ascl1 regulates tangential migration remains unclear. Here, we found that Ascl1 promoted tangential migration along the ventricular zone/subventricular zone (VZ/SVZ) and intermediate zone (IZ) of the dorsal telencephalon. Distal-less homeobox 2 (Dlx2) acted downstream of Ascl1 in promoting tangential migration along the VZ/SVZ but not IZ. We further identified Eph receptor B2 (Ephb2) as a direct target of Ascl1. Knockdown of EphB2 disrupted the separation of the VZ/SVZ and IZ migratory routes. Ephrin-A5, a ligand of EphB2, was sufficient to repel both Ascl1-expressing cells in vitro and tangentially migrating cortical interneurons in vivo. Together, our results demonstrate that Ascl1 induces expression of Dlx2 and Ephb2 to maintain distinct tangential migratory routes in the dorsal telencephalon. PMID:28276447

  1. The bHLH transcription factor Ascl1a is essential for the specification of the intestinal secretory cells and mediates Notch signaling in the zebrafish intestine.

    PubMed

    Flasse, Lydie C; Stern, David G; Pirson, Justine L; Manfroid, Isabelle; Peers, Bernard; Voz, Marianne L

    2013-04-15

    Notch signaling has a fundamental role in stem cell maintenance and in cell fate choice in the intestine of different species. Canonically, Notch signaling represses the expression of transcription factors of the achaete-scute like (ASCL) or atonal related protein (ARP) families. Identifying the ARP/ASCL genes expressed in the gastrointestinal tract is essential to build the regulatory cascade controlling the differentiation of gastrointestinal progenitors into the different intestinal cell types. The expression of the ARP/ASCL factors was analyzed in zebrafish to identify, among all the ARP/ASCL factors found in the zebrafish genome, those expressed in the gastrointestinal tract. ascl1a was found to be the earliest factor detected in the intestine. Loss-of-function analyses using the pia/ascl1a mutant, revealed that ascl1a is crucial for the differentiation of all secretory cells. Furthermore, we identify a battery of transcription factors expressed during secretory cell differentiation and downstream of ascl1a. Finally, we show that the repression of secretory cell fate by Notch signaling is mediated by the inhibition of ascl1a expression. In conclusion, this work identifies Ascl1a as a key regulator of the secretory cell lineage in the zebrafish intestine, playing the same role as Atoh1 in the mouse intestine. This highlights the diversity in the ARP/ASCL family members acting as cell fate determinants downstream from Notch signaling. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Immunohistochemical study of the neural development transcription factors (TTF1, ASCL1 and BRN2) in neuroendocrine prostate tumours.

    PubMed

    Rodríguez-Zarco, E; Vallejo-Benítez, A; Umbría-Jiménez, S; Pereira-Gallardo, S; Pabón-Carrasco, S; Azueta, A; González-Cámpora, R; Espinal, P S; García-Escudero, A

    2017-10-01

    Prostatic small-cell neuroendocrine carcinoma is an uncommon malignancy that constitutes 0.5-1% of all prostate malignancies. The median cancer-specific survival of patients with prostatic small-cell neuroendocrine carcinoma is 19 months, and 60.5% of the patients have metastatic disease. Neural development transcription factors are molecules involved in the organogenesis of the central nervous system and of neuroendocrine precursors of various tissues, including the suprarenal gland, thyroid glands, lungs and prostate. We present 3 cases of this uncommon condition, applying the new World Health Organisation criteria. We conducted studies through haematoxylin and eosin staining and analysed the expression of the neural development transcription factors achaete-scute homolog like 1, thyroid transcription factor 1 and the class III/IV POU transcription factors, as a new research line in the carcinogenesis of prostatic neuroendocrine tumours. In case 1, there was no TTF1 immunoexpression. Cases 2 and 3 had positive immunostaining for ASCL1, and Case 1 had negative immunostaining. BRN2 immunostaining was negative in case 1 and positive in cases 2 and 3. The World Health Organisation does not recognise any molecular or genetic marker with prognostic value. ASCL-1 is related to the NOTCH and WNT signalling pathways. ASCL-1, TTF1 and BRN2 could be used for early diagnosis and as prognostic factors and therapeutic targets. Copyright © 2017 AEU. All rights reserved.

  3. Reprogramming A375 cells to induced-resembled neuronal cells by structured overexpression of specific transcription genes

    PubMed Central

    Zhang, Hengzhu; Wei, Min; Jiang, Yangyang; Wang, Xiaodong; She, Lei; Yan, Zhengcun; Dong, Lun; Pang, Lujun; Wang, Xingdong

    2016-01-01

    Induced-resembled neuronal cells (irNCs) are generated by reprogramming human melanoma cells through the introduction of key transcription factors, providing novel concepts in the treatment of malignant tumor cells and making it possible to supply neural cells for laboratory use. In the present study, irNCs were derived from A375 cells by inducing the 'forced' overexpression of specific genes, including achaete-scute homolog 1 (Ascl1), neuronal differentiation factor 1 (Neurod1), myelin transcription factor 1 (Myt1), brain protein 2 (Brn2, also termed POU3F2) and human brain-derived neurotrophic factor (h-BDNF). irNCs induced from A375 cells express multiple neuronal markers and fire action potentials, exhibiting properties similar to those of motor neurons. The reprogramming procedure comprised reverse transcription-polymerase chain reaction and immunofluorescence staining; furthermore, electrophysiological profiling demonstrated the characteristics of the induced-resembled neurons. The present study obtained a novel type of human irNC from human melanoma, which secreted BDNF continuously, providing a model for neuron-like cells. Thus, irNCs offer promise in investigating various neural diseases by using neural-like cells derived directly from the patient of interest. PMID:27510459

  4. SDF-1/CXCR4 Signaling Maintains Stemness Signature in Mouse Neural Stem/Progenitor Cells.

    PubMed

    Ho, Shih-Yin; Ling, Thai-Yen; Lin, Hsing-Yu; Liou, Jeffrey Tsai-Jui; Liu, Fei-Chih; Chen, I-Chun; Lee, Sue-Wei; Hsu, Yu; Lai, Dar-Ming; Liou, Horng-Huei

    2017-01-01

    SDF-1 and its primary receptor, CXCR4, are highly expressed in the embryonic central nervous system (CNS) and play a crucial role in brain architecture. Loss of SDF-1/CXCR4 signaling causes abnormal development of neural stem/progenitor cells (NSCs/NPCs) in the cerebellum, hippocampus, and cortex. However, the mechanism of SDF-1/CXCR4 axis in NSCs/NPCs regulation remains unknown. In this study, we found that elimination of SDF-1/CXCR4 transduction caused NSCs/NPCs to lose their stemness characteristics and to encounter neurogenic differentiation. Moreover, Notch and RE1 silencing transcription factor (REST) both play an essential role in NSCs/NPCs maintenance and neuronal differentiation and were dramatically downregulated following SDF-1/CXCR4 cascade inhibition. Finally, we demonstrated that the expression of achaete-scute homolog 1 (Ascl1), a proneural gene, and p27, an antiproliferative gene, were significantly increased after genetic elimination of SDF-1 alleles. Our results support that the loss of functional SDF-1/CXCR4 signaling pathway in NSCs/NPCs induces exit of cell cycle and promotes premature neural differentiation.

  5. ASCL1 is a lineage oncogene providing therapeutic targets for high-grade neuroendocrine lung cancers.

    PubMed

    Augustyn, Alexander; Borromeo, Mark; Wang, Tao; Fujimoto, Junya; Shao, Chunli; Dospoy, Patrick D; Lee, Victoria; Tan, Christopher; Sullivan, James P; Larsen, Jill E; Girard, Luc; Behrens, Carmen; Wistuba, Ignacio I; Xie, Yang; Cobb, Melanie H; Gazdar, Adi F; Johnson, Jane E; Minna, John D

    2014-10-14

    Aggressive neuroendocrine lung cancers, including small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), represent an understudied tumor subset that accounts for approximately 40,000 new lung cancer cases per year in the United States. No targeted therapy exists for these tumors. We determined that achaete-scute homolog 1 (ASCL1), a transcription factor required for proper development of pulmonary neuroendocrine cells, is essential for the survival of a majority of lung cancers (both SCLC and NSCLC) with neuroendocrine features. By combining whole-genome microarray expression analysis performed on lung cancer cell lines with ChIP-Seq data designed to identify conserved transcriptional targets of ASCL1, we discovered an ASCL1 target 72-gene expression signature that (i) identifies neuroendocrine differentiation in NSCLC cell lines, (ii) is predictive of poor prognosis in resected NSCLC specimens from three datasets, and (iii) represents novel "druggable" targets. Among these druggable targets is B-cell CLL/lymphoma 2, which when pharmacologically inhibited stops ASCL1-dependent tumor growth in vitro and in vivo and represents a proof-of-principle ASCL1 downstream target gene. Analysis of downstream targets of ASCL1 represents an important advance in the development of targeted therapy for the neuroendocrine class of lung cancers, providing a significant step forward in the understanding and therapeutic targeting of the molecular vulnerabilities of neuroendocrine lung cancer.

  6. ASCL1 is a lineage oncogene providing therapeutic targets for high-grade neuroendocrine lung cancers

    PubMed Central

    Augustyn, Alexander; Borromeo, Mark; Wang, Tao; Fujimoto, Junya; Shao, Chunli; Dospoy, Patrick D.; Lee, Victoria; Tan, Christopher; Sullivan, James P.; Larsen, Jill E.; Girard, Luc; Behrens, Carmen; Wistuba, Ignacio I.; Xie, Yang; Cobb, Melanie H.; Gazdar, Adi F.; Johnson, Jane E.; Minna, John D.

    2014-01-01

    Aggressive neuroendocrine lung cancers, including small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), represent an understudied tumor subset that accounts for approximately 40,000 new lung cancer cases per year in the United States. No targeted therapy exists for these tumors. We determined that achaete-scute homolog 1 (ASCL1), a transcription factor required for proper development of pulmonary neuroendocrine cells, is essential for the survival of a majority of lung cancers (both SCLC and NSCLC) with neuroendocrine features. By combining whole-genome microarray expression analysis performed on lung cancer cell lines with ChIP-Seq data designed to identify conserved transcriptional targets of ASCL1, we discovered an ASCL1 target 72-gene expression signature that (i) identifies neuroendocrine differentiation in NSCLC cell lines, (ii) is predictive of poor prognosis in resected NSCLC specimens from three datasets, and (iii) represents novel “druggable” targets. Among these druggable targets is B-cell CLL/lymphoma 2, which when pharmacologically inhibited stops ASCL1-dependent tumor growth in vitro and in vivo and represents a proof-of-principle ASCL1 downstream target gene. Analysis of downstream targets of ASCL1 represents an important advance in the development of targeted therapy for the neuroendocrine class of lung cancers, providing a significant step forward in the understanding and therapeutic targeting of the molecular vulnerabilities of neuroendocrine lung cancer. PMID:25267614

  7. HEN1 and HEN2: a subgroup of basic helix-loop-helix genes that are coexpressed in a human neuroblastoma.

    PubMed Central

    Brown, L; Espinosa, R; Le Beau, M M; Siciliano, M J; Baer, R

    1992-01-01

    An important family of regulatory molecules is made up of proteins that possess the DNA-binding and dimerization motif known as the basic helix-loop-helix (bHLH) domain. The bHLH family includes subgroups of closely related proteins that share common functional properties and overlapping patterns of expression (e.g., the MyoD1 and achaete-scute subgroups). In this report we describe HEN1 and HEN2, mammalian genes that encode a distinct subgroup of bHLH proteins. The HEN1 gene was identified on the basis of cross-hybridization with TAL1, a known bHLH gene implicated in T-cell acute lymphoblastic leukemia. In situ fluorescence hybridization was used to localize the human HEN1 gene to chromosome band 1q22. HEN1 and HEN2 are coexpressed in the IMR-32 human neuroblastoma cell line, and they encode highly related proteins of 133 and 135 residues, respectively, that share 98% amino acid identity in their hHLH domains. These data imply that the bHLH protein subgroup encoded by HEN1 and HEN2 may serve important regulatory functions in the developing nervous system. Images PMID:1528853

  8. Silencing of the EPHB3 tumor-suppressor gene in human colorectal cancer through decommissioning of a transcriptional enhancer

    PubMed Central

    Jägle, Sabine; Rönsch, Kerstin; Timme, Sylvia; Andrlová, Hana; Bertrand, Miriam; Jäger, Marcel; Proske, Amelie; Schrempp, Monika; Yousaf, Afsheen; Michoel, Tom; Zeiser, Robert; Werner, Martin; Lassmann, Silke; Hecht, Andreas

    2014-01-01

    The protein tyrosine kinase Ephrin type-B receptor 3 (EPHB3) counteracts tumor-cell dissemination by regulating intercellular adhesion and repulsion and acts as tumor/invasion suppressor in colorectal cancer. This protective mechanism frequently collapses at the adenoma–carcinoma transition due to EPHB3 transcriptional silencing. Here, we identify a transcriptional enhancer at the EPHB3 gene that integrates input from the intestinal stem-cell regulator achaete-scute family basic helix-loop-helix transcription factor 2 (ASCL2), Wnt/β-catenin, MAP kinase, and Notch signaling. EPHB3 enhancer activity is highly variable in colorectal carcinoma cells and precisely reflects EPHB3 expression states, suggesting that enhancer dysfunction underlies EPHB3 silencing. Interestingly, low Notch activity parallels reduced EPHB3 expression in colorectal carcinoma cell lines and poorly differentiated tumor-tissue specimens. Restoring Notch activity reestablished enhancer function and EPHB3 expression. Although essential for intestinal stem-cell maintenance and adenoma formation, Notch activity seems dispensable in colorectal carcinomas. Notch activation even promoted growth arrest and apoptosis of colorectal carcinoma cells, attenuated their self-renewal capacity in vitro, and blocked tumor growth in vivo. Higher levels of Notch activity also correlated with longer disease-free survival of colorectal cancer patients. In summary, our results uncover enhancer decommissioning as a mechanism for transcriptional silencing of the EPHB3 tumor suppressor and argue for an antitumorigenic function of Notch signaling in advanced colorectal cancer. PMID:24707046

  9. Silencing of the EPHB3 tumor-suppressor gene in human colorectal cancer through decommissioning of a transcriptional enhancer.

    PubMed

    Jägle, Sabine; Rönsch, Kerstin; Timme, Sylvia; Andrlová, Hana; Bertrand, Miriam; Jäger, Marcel; Proske, Amelie; Schrempp, Monika; Yousaf, Afsheen; Michoel, Tom; Zeiser, Robert; Werner, Martin; Lassmann, Silke; Hecht, Andreas

    2014-04-01

    The protein tyrosine kinase Ephrin type-B receptor 3 (EPHB3) counteracts tumor-cell dissemination by regulating intercellular adhesion and repulsion and acts as tumor/invasion suppressor in colorectal cancer. This protective mechanism frequently collapses at the adenoma-carcinoma transition due to EPHB3 transcriptional silencing. Here, we identify a transcriptional enhancer at the EPHB3 gene that integrates input from the intestinal stem-cell regulator achaete-scute family basic helix-loop-helix transcription factor 2 (ASCL2), Wnt/β-catenin, MAP kinase, and Notch signaling. EPHB3 enhancer activity is highly variable in colorectal carcinoma cells and precisely reflects EPHB3 expression states, suggesting that enhancer dysfunction underlies EPHB3 silencing. Interestingly, low Notch activity parallels reduced EPHB3 expression in colorectal carcinoma cell lines and poorly differentiated tumor-tissue specimens. Restoring Notch activity reestablished enhancer function and EPHB3 expression. Although essential for intestinal stem-cell maintenance and adenoma formation, Notch activity seems dispensable in colorectal carcinomas. Notch activation even promoted growth arrest and apoptosis of colorectal carcinoma cells, attenuated their self-renewal capacity in vitro, and blocked tumor growth in vivo. Higher levels of Notch activity also correlated with longer disease-free survival of colorectal cancer patients. In summary, our results uncover enhancer decommissioning as a mechanism for transcriptional silencing of the EPHB3 tumor suppressor and argue for an antitumorigenic function of Notch signaling in advanced colorectal cancer.

  10. Neurotrophin-3 promotes the cholinergic differentiation of sympathetic neurons

    PubMed Central

    Brodski, Claude; Schnürch, Harald; Dechant, Georg

    2000-01-01

    Neurotrophins influence the epigenetic shaping of the vertebrate nervous system by regulating neuronal numbers during development and synaptic plasticity. Here we attempt to determine whether these growth factors can also regulate neurotransmitter plasticity. As a model system we used the selection between noradrenergic and cholinergic neurotransmission by paravertebral sympathetic neurons. Developing sympathetic neurons express the neurotrophin receptors TrkA and TrkC, two highly related receptor tyrosine kinases. Whereas the TrkA ligand nerve growth factor (NGF) has long been known to regulate both the survival and the expression of noradrenergic traits in sympathetic neurons, the role of TrkC and of its ligand neurotrophin-3 (NT3) has remained unclear. We found that TrkC expression in the avian sympathetic chain overlaps substantially with that of choline acetyltransferase. In sympathetic chain explants, transcripts of the cholinergic marker genes choline acetyltransferase and vasoactive intestinal polypeptide were strongly enriched in the presence of NT3 compared with NGF, whereas the noradrenergic markers tyrosine hydroxylase and norepinephrine transporter were reduced. The transcription factor chicken achaete scute homolog 1 was coexpressed with cholinergic markers. The effects of NT3 are reversed and antagonized by NGF. They are independent of neuronal survival and developmentally regulated. These results suggest a role for NT3 as a differentiation factor for cholinergic neurons and establish a link between neurotrophins and neurotransmitter plasticity. PMID:10931939

  11. ASCL1 reprograms mouse Müller glia into neurogenic retinal progenitors

    PubMed Central

    Pollak, Julia; Wilken, Matthew S.; Ueki, Yumi; Cox, Kristen E.; Sullivan, Jane M.; Taylor, Russell J.; Levine, Edward M.; Reh, Thomas A.

    2013-01-01

    Non-mammalian vertebrates have a robust ability to regenerate injured retinal neurons from Müller glia (MG) that activate the gene encoding the proneural factor Achaete-scute homolog 1 (Ascl1; also known as Mash1 in mammals) and de-differentiate into progenitor cells. By contrast, mammalian MG have a limited regenerative response and fail to upregulate Ascl1 after injury. To test whether ASCL1 could restore neurogenic potential to mammalian MG, we overexpressed ASCL1 in dissociated mouse MG cultures and intact retinal explants. ASCL1-infected MG upregulated retinal progenitor-specific genes and downregulated glial genes. Furthermore, ASCL1 remodeled the chromatin at its targets from a repressive to an active configuration. MG-derived progenitors differentiated into cells that exhibited neuronal morphologies, expressed retinal subtype-specific neuronal markers and displayed neuron-like physiological responses. These results indicate that a single transcription factor, ASCL1, can induce a neurogenic state in mature MG. PMID:23637330

  12. Embryonic development of the nervous system in the planarian Schmidtea polychroa.

    PubMed

    Monjo, Francisco; Romero, Rafael

    2015-01-15

    The development of a nervous system is a key innovation in the evolution of metazoans, which is illustrated by the presence of a common developmental toolkit for the formation of this organ system. Neurogenesis in the Spiralia, in particular the Platyhelminthes, is, however, poorly understood when compared with other animal groups. Here, we characterize embryonic neurogenesis in the freshwater flatworm Schmidtea polychroa and analyze the expression of soxB and a set of proneural bHLH genes, which are gene families with a well-established role in metazoan early neural development. We show that the nervous system is fully de novo assembled after the early embryo ingests the maternal nutrients. At early stages of neurogenesis, soxB1 genes are expressed in putative neural progenitor cells, whereas soxB2 and neural bHLH genes (achaete-scute, neuroD and beta3) are associated with late neurogenesis and the specification of neural subpopulations of the central and peripheral nervous system. Our findings are consistent with the role of proneural genes in other bilaterians, suggesting that the ancestral neural-specific gene regulatory network is conserved in triclads, despite exhibiting a divergent mode of development.

  13. High catalytic activity of heteropolynuclear cyanide complexes containing cobalt and platinum ions: visible-light driven water oxidation.

    PubMed

    Yamada, Yusuke; Oyama, Kohei; Gates, Rachel; Fukuzumi, Shunichi

    2015-05-04

    A near-stoichiometric amount of O2 was evolved as observed in the visible-light irradiation of an aqueous buffer (pH 8) containing [Ru(II) (2,2'-bipyridine)3 ] as a photosensitizer, Na2 S2 O8 as a sacrificial electron acceptor, and a heteropolynuclear cyanide complex as a water-oxidation catalyst. The heteropolynuclear cyanide complexes exhibited higher catalytic activity than a polynuclear cyanide complex containing only Co(III) or Pt(IV) ions as C-bound metal ions. The origin of the synergistic effect between Co and Pt ions is discussed in relation to electronic and local atomic structures of the complexes.

  14. Complexity and Diversity of Digraphs

    NASA Astrophysics Data System (ADS)

    Bertz, Steven H.; Pereira, Gil Z.; Zamfirescu, Christina M. D.

    There has been a great deal of ferment in `Complexity Science' in recent years, as chronicled in the proceedings of the New England Complex Systems Institute's International Conference on Complex Systems [Minai & Bar-Yam 2006, 2008] and those of the Santa Fe Institute [Nadel & Stein 1995, Cowan 1994]. We have been primarily focused on developing metrics of complexity relevant to chemistry, especially synthetic chemistry [Bertz 2003a-c]. Our approach involves abstracting a molecule or a plan for its synthesis as a graph and then using the tools of graph theory to characterize its complexity and diversity.

  15. Grammatical complexity of strange sets

    NASA Astrophysics Data System (ADS)

    Auerbach, Ditza; Procaccia, Itamar

    1990-06-01

    Chaotic dynamical systems can be organized around an underlying strange set, which is comprised of all the unstable periodic orbits. In this paper, we quantify the complexity of such an organization; this complexity addresses the difficulty of predicting the structure of the strange set from low-order data and is independent of the entropy and the algorithmic complexity. We refer to the new measure as the grammatical complexity. The notion is introduced, discussed, and illustrated in the context of simple dynamical systems. In addition, the grammatical complexity is generalized to include metric properties arising due to the nonuniform distribution of the invariant measure on the strange set.

  16. The Mycobacterium avium complex.

    PubMed Central

    Inderlied, C B; Kemper, C A; Bermudez, L E

    1993-01-01

    Mycobacterium avium complex (MAC) disease emerged early in the epidemic of AIDS as one of the common opportunistic infections afflicting human immunodeficiency virus-infected patients. However, only over the past few years has a consensus developed about its significance to the morbidity and mortality of AIDS. M. avium was well known to mycobacteriologists decades before AIDS, and the MAC was known to cause disease, albeit uncommon, in humans and animals. The early interest in the MAC provided a basis for an explosion of studies over the past 10 years largely in response to the role of the MAC in AIDS opportunistic infection. Molecular techniques have been applied to the epidemiology of MAC disease as well as to a better understanding of the genetics of antimicrobial resistance. The interaction of the MAC with the immune system is complex, and putative MAC virulence factors appear to have a direct effect on the components of cellular immunity, including the regulation of cytokine expression and function. There now is compelling evidence that disseminated MAC disease in humans contributes to both a decrease in the quality of life and survival. Disseminated disease most commonly develops late in the course of AIDS as the CD4 cells are depleted below a critical threshold, but new therapies for prophylaxis and treatment offer considerable promise. These new therapeutic modalities are likely to be useful in the treatment of other forms of MAC disease in patients without AIDS. The laboratory diagnosis of MAC disease has focused on the detection of mycobacteria in the blood and tissues, and although the existing methods are largely adequate, there is need for improvement. Indeed, the successful treatment of MAC disease clearly will require an early and rapid detection of the MAC in clinical specimens long before the establishment of the characteristic overwhelming infection of bone marrow, liver, spleen, and other tissue. Also, a standard method of susceptibility testing

  17. Understanding complex chiral plasmonics

    NASA Astrophysics Data System (ADS)

    Duan, Xiaoyang; Yue, Song; Liu, Na

    2015-10-01

    Chiral nanoplasmonics exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response within nanoscale metallic structures. Recently, a number of different approaches have been utilized to create chiral nanoplasmonic structures. However, particularly for tailoring nanooptical chiral sensing devices, the understanding of the resulting chiroptical response when coupling chiral and achiral structures together is crucial and has not been completely understood to date. Here, we present a thorough and step-by-step experimental study to understand the intriguing chiral-achiral coupling scheme. We set up a hybrid plasmonic system, which bears resemblance to the `host-guest' system in supramolecular chemistry to analyze and explain the complex chiral response both at the chiral and achiral plasmonic resonances. We also provide an elegant and simple analytical model, which can describe, predict, and comprehend the chiroptical spectra in detail. Our study will shed light on designing well-controlled chiral-achiral coupling platforms for reliable chiral sensing.Chiral nanoplasmonics exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response within nanoscale metallic structures. Recently, a number of different approaches have been utilized to create chiral nanoplasmonic structures. However, particularly for tailoring nanooptical chiral sensing devices, the understanding of the resulting chiroptical response when coupling chiral and achiral structures together is crucial and has not been completely understood to date. Here, we present a thorough and step-by-step experimental study to understand the intriguing chiral-achiral coupling scheme. We set up a hybrid plasmonic system, which bears resemblance to the `host-guest' system in supramolecular chemistry to analyze and explain the complex chiral response both at the chiral and achiral plasmonic resonances. We also provide an elegant

  18. Complexity of formation in holography

    NASA Astrophysics Data System (ADS)

    Chapman, Shira; Marrochio, Hugo; Myers, Robert C.

    2017-01-01

    It was recently conjectured that the quantum complexity of a holographic boundary state can be computed by evaluating the gravitational action on a bulk region known as the Wheeler-DeWitt patch. We apply this complexity=action duality to evaluate the `complexity of formation' [1, 2], i.e. the additional complexity arising in preparing the entangled thermofield double state with two copies of the boundary CFT compared to preparing the individual vacuum states of the two copies. We find that for boundary dimensions d > 2, the difference in the complexities grows linearly with the thermal entropy at high temperatures. For the special case d = 2, the complexity of formation is a fixed constant, independent of the temperature. We compare these results to those found using the complexity=volume duality.

  19. Complexity of vesicle microcirculation

    NASA Astrophysics Data System (ADS)

    Kaoui, B.; Tahiri, N.; Biben, T.; Ez-Zahraouy, H.; Benyoussef, A.; Biros, G.; Misbah, C.

    2011-10-01

    This study focuses numerically on dynamics in two dimensions of vesicles in microcirculation. The method used is based on boundary integral formulation. This study is inspired by the behavior of red blood cells (RBCs) in the microvasculature. Red RBCs carry oxygen from the lungs and deliver it through the microvasculature. The shape adopted by RBCs can affect blood flow and influence oxygen delivery. Our simulation using vesicles (a simple model for RBC) reveals unexpected complexity as compared to the case where a purely unbounded Poiseuille flow is considered [Kaoui, Biros, and Misbah, Phys. Rev. Lett.10.1103/PhysRevLett.103.188101 103, 188101 (2009)]. In sufficiently large channels (in the range of 100μm; the vesicle size and its reduced volume are taken in the range of those of a human RBC), such as arterioles, a slipperlike (asymmetric) shape prevails. A parachutelike (symmetric) shape is adopted in smaller channels (in the range of 20μm, as in venules), but this shape loses stability and again changes to a pronounced slipperlike morphology in channels having a size typical of capillaries (5-10 μm). Stiff membranes, mimicking malaria infection, for example, adopt a centered or off-centered snakelike locomotion instead (the denomination snaking is used for this regime). A general scenario of how and why vesicles adopt their morphologies and dynamics among several distinct possibilities is provided. This finding potentially points to nontrivial RBCs dynamics in the microvasculature.

  20. Information Complexity and Biology

    NASA Astrophysics Data System (ADS)

    Bagnoli, Franco; Bignone, Franco A.; Cecconi, Fabio; Politi, Antonio

    Kolmogorov contributed directly to Biology in essentially three problems: the analysis of population dynamics (Lotka-Volterra equations), the reaction-diffusion formulation of gene spreading (FKPP equation), and some discussions about Mendel's laws. However, the widely recognized importance of his contribution arises from his work on algorithmic complexity. In fact, the limited direct intervention in Biology reflects the generally slow growth of interest of mathematicians towards biological issues. From the early work of Vito Volterra on species competition, to the slow growth of dynamical systems theory, contributions to the study of matter and the physiology of the nervous system, the first 50-60 years have witnessed important contributions, but as scattered pieces apparently uncorrelated, and in branches often far away from Biology. Up to the 40' it is hard to see the initial loose build up of a convergence, for those theories that will become mainstream research by the end of the century, and connected by the study of biological systems per-se.

  1. Sociality influences cultural complexity

    PubMed Central

    Muthukrishna, Michael; Shulman, Ben W.; Vasilescu, Vlad; Henrich, Joseph

    2014-01-01

    Archaeological and ethnohistorical evidence suggests a link between a population's size and structure, and the diversity or sophistication of its toolkits or technologies. Addressing these patterns, several evolutionary models predict that both the size and social interconnectedness of populations can contribute to the complexity of its cultural repertoire. Some models also predict that a sudden loss of sociality or of population will result in subsequent losses of useful skills/technologies. Here, we test these predictions with two experiments that permit learners to access either one or five models (teachers). Experiment 1 demonstrates that naive participants who could observe five models, integrate this information and generate increasingly effective skills (using an image editing tool) over 10 laboratory generations, whereas those with access to only one model show no improvement. Experiment 2, which began with a generation of trained experts, shows how learners with access to only one model lose skills (in knot-tying) more rapidly than those with access to five models. In the final generation of both experiments, all participants with access to five models demonstrate superior skills to those with access to only one model. These results support theoretical predictions linking sociality to cumulative cultural evolution. PMID:24225461

  2. [Toxic complex from parrotfish].

    PubMed

    Chungue, E; Bagnis, R; Fusetani, N; Yasumoto, T

    1977-01-01

    Clinical and epidemiological observations suggested that a complex toxic molecule is involved in the parrotfish flesh (Scarus gibbus) poisoning from Gambier Islands. The fat soluble extract obtained from the muscles upon ciguatoxin preparation showed two toxic substances after fractionation by DEAE cellulose column chromatography. The major toxin is different from ciguatoxin judging by its chromatographic behaviour. The other is closely similar to (or identical with) ciguatoxin from the moray eel Gymnothorax javanicus. They were named SG1 for the new toxin and SG2 for the ciguatoxin like compound. Successive filtrations on Sephadex LH-20 of SG1 and SG2 gave respectively a lethality to mice of 0.03 microgram/g and 0.06 microgram/g. SG1, specifically occurs in the muscles of the parrotfish family (scaritoxin) while it is absent from other ciguateric fishes. According to that specificity and the lack of SG1 in S. gibbus liver and gut contents, the origin of scaritoxin is briefly discussed.

  3. Complex Sleep Apnea Syndrome

    PubMed Central

    Khan, Muhammad Talha; Franco, Rose Amy

    2014-01-01

    Complex sleep apnea is the term used to describe a form of sleep disordered breathing in which repeated central apneas (>5/hour) persist or emerge when obstructive events are extinguished with positive airway pressure (PAP) and for which there is not a clear cause for the central apneas such as narcotics or systolic heart failure. The driving forces in the pathophysiology are felt to be ventilator instability associated oscillation in PaCO2 arterial partial pressure of Carbon Dioxide, continuous cositive airway pressure (CPAP) related increased CO2 carbon dioxide elimination, and activation of airway and pulmonary stretch receptors triggering these central apneas. The prevalence ranges from 0.56% to 18% with no clear predictive characteristics as compared to simple obstructive sleep apnea. Prognosis is similar to obstructive sleep apnea. The central apnea component in most patients on followup using CPAP therap, has resolved. For those with continued central apneas on simple CPAP therapy, other treatment options include bilevel PAP, adaptive servoventilation, permissive flow limitation and/or drugs. PMID:24693440

  4. Sociality influences cultural complexity.

    PubMed

    Muthukrishna, Michael; Shulman, Ben W; Vasilescu, Vlad; Henrich, Joseph

    2014-01-07

    Archaeological and ethnohistorical evidence suggests a link between a population's size and structure, and the diversity or sophistication of its toolkits or technologies. Addressing these patterns, several evolutionary models predict that both the size and social interconnectedness of populations can contribute to the complexity of its cultural repertoire. Some models also predict that a sudden loss of sociality or of population will result in subsequent losses of useful skills/technologies. Here, we test these predictions with two experiments that permit learners to access either one or five models (teachers). Experiment 1 demonstrates that naive participants who could observe five models, integrate this information and generate increasingly effective skills (using an image editing tool) over 10 laboratory generations, whereas those with access to only one model show no improvement. Experiment 2, which began with a generation of trained experts, shows how learners with access to only one model lose skills (in knot-tying) more rapidly than those with access to five models. In the final generation of both experiments, all participants with access to five models demonstrate superior skills to those with access to only one model. These results support theoretical predictions linking sociality to cumulative cultural evolution.

  5. Fact Sheet: Range Complex

    NASA Technical Reports Server (NTRS)

    Cornelson, C.; Fretter, E.

    2004-01-01

    NASA Ames has a long tradition in leadership with the use of ballistic ranges and shock tubes for the purpose of studying the physics and phenomena associated with hypervelocity flight. Cutting-edge areas of research run the gamut from aerodynamics, to impact physics, to flow-field structure and chemistry. This legacy of testing began in the NACA era of the 1940's with the Supersonic Free Flight Tunnel, and evolved dramatically up through the late 1950s with the pioneering work in the Ames Hypersonic Ballistic Range. The tradition continued in the mid-60s with the commissioning of the three newest facilities: the Ames Vertical Gun Range (AVGR) in 1964, the Hypervelocity Free Flight Facility (HFFF) in 1965 and the Electric Arc Shock Tube (EAST) in 1966. Today the Range Complex continues to provide unique and critical testing in support of the Nation's programs for planetary geology and geophysics; exobiology; solar system origins; earth atmospheric entry, planetary entry, and aerobraking vehicles; and various configurations for supersonic and hypersonic aircraft.

  6. It is complicated! - misunderstanding the complexities of 'complex'.

    PubMed

    Sturmberg, Joachim P; Martin, Carmel M; Katerndahl, David A

    2017-04-01

    Terminology matters - as Lakoff emphasised, words and phrases evoke powerful images and frames of understanding. It is for that reason that we need to discern and use appropriately the term complex/complexity in the health science/professional/policy domain. Complex is the fashionable term used when in reality one means 'complicated', 'difficult to understand' or 'multiple simultaneous actions'. However, this is not what complex means. The Latin term means 'entwined/interwoven' - a structural characteristic describing systems. Complexity arises from the interactions between structurally connected entities - a functional characteristic of a system. The basis of scientific rigor is a clear understanding of a discipline's epistemology. Complexity refers to the emergence of outcomes from the interactions of a system's constituent components (and thus has nothing in common with the colloquial meaning of complicatedness). © 2016 John Wiley & Sons, Ltd.

  7. Complexity measurement based on information theory and kolmogorov complexity.

    PubMed

    Lui, Leong Ting; Terrazas, Germán; Zenil, Hector; Alexander, Cameron; Krasnogor, Natalio

    2015-01-01

    In the past decades many definitions of complexity have been proposed. Most of these definitions are based either on Shannon's information theory or on Kolmogorov complexity; these two are often compared, but very few studies integrate the two ideas. In this article we introduce a new measure of complexity that builds on both of these theories. As a demonstration of the concept, the technique is applied to elementary cellular automata and simulations of the self-organization of porphyrin molecules.

  8. Physical Complexity and Cognitive Evolution

    NASA Astrophysics Data System (ADS)

    Jedlicka, Peter

    Our intuition tells us that there is a general trend in the evolution of nature, a trend towards greater complexity. However, there are several definitions of complexity and hence it is difficult to argue for or against the validity of this intuition. Christoph Adami has recently introduced a novel measure called physical complexity that assigns low complexity to both ordered and random systems and high complexity to those in between. Physical complexity measures the amount of information that an organism stores in its genome about the environment in which it evolves. The theory of physical complexity predicts that evolution increases the amount of `knowledge' an organism accumulates about its niche. It might be fruitful to generalize Adami's concept of complexity to the entire evolution (including the evolution of man). Physical complexity fits nicely into the philosophical framework of cognitive biology which considers biological evolution as a progressing process of accumulation of knowledge (as a gradual increase of epistemic complexity). According to this paradigm, evolution is a cognitive `ratchet' that pushes the organisms unidirectionally towards higher complexity. Dynamic environment continually creates problems to be solved. To survive in the environment means to solve the problem, and the solution is an embodied knowledge. Cognitive biology (as well as the theory of physical complexity) uses the concepts of information and entropy and views the evolution from both the information-theoretical and thermodynamical perspective. Concerning humans as conscious beings, it seems necessary to postulate an emergence of a new kind of knowledge - a self-aware and self-referential knowledge. Appearence of selfreflection in evolution indicates that the human brain reached a new qualitative level in the epistemic complexity.

  9. What is a complex graph?

    NASA Astrophysics Data System (ADS)

    Kim, Jongkwang; Wilhelm, Thomas

    2008-04-01

    Many papers published in recent years show that real-world graphs G(n,m) ( n nodes, m edges) are more or less “complex” in the sense that different topological features deviate from random graphs. Here we narrow the definition of graph complexity and argue that a complex graph contains many different subgraphs. We present different measures that quantify this complexity, for instance C1e, the relative number of non-isomorphic one-edge-deleted subgraphs (i.e. DECK size). However, because these different subgraph measures are computationally demanding, we also study simpler complexity measures focussing on slightly different aspects of graph complexity. We consider heuristically defined “product measures”, the products of two quantities which are zero in the extreme cases of a path and clique, and “entropy measures” quantifying the diversity of different topological features. The previously defined network/graph complexity measures Medium Articulation and Offdiagonal complexity ( OdC) belong to these two classes. We study OdC measures in some detail and compare it with our new measures. For all measures, the most complex graph G has a medium number of edges, between the edge numbers of the minimum and the maximum connected graph n-1complexity measures are characterized with the help of different example graphs. For all measures the corresponding time complexity is given. Finally, we discuss the complexity of 33 real-world graphs of different biological, social and economic systems with the six computationally most simple measures (including OdC). The complexities of the real graphs are compared with average complexities of two different random graph versions: complete random graphs (just fixed n,m) and rewired graphs with fixed node degrees.

  10. Complex oxides: Intricate disorder

    DOE PAGES

    Uberuaga, Blas Pedro

    2016-02-29

    In this study, complex oxides such as pyrochlores have a myriad of potential technological applications, including as fast ion conductors and radiation-tolerant nuclear waste forms. They are also of interest for their catalytic and spin ice properties. Many of these functional properties are enabled by the atomic structure of the cation sublattices. Pyrochlores (A2B2O7) contain two different cations (A and B), typically a 3+ rare earth and a 4+ transition metal such as Hf, Zr, or Ti. The large variety of chemistries that can form pyrochlores leads to a rich space in which to search for exotic new materials. Furthermore,more » how cations order or disorder on their respective sublattices for a given chemical composition influences the functional properties of the oxide. For example, oxygen ionic conductivity is directly correlated with the level of cation disorder — the swapping of A and B cations1. Further, the resistance of these materials against amorphization has also been connected with the ability of the cations to disorder2, 3. These correlations between cation structure and functionality have spurred great interest in the structure of the cation sublattice under irradiation, with significant focus on the disordering mechanisms and disordered structure. Previous studies have found that, upon irradiation, pyrochlores often undergo an order-to-disorder transformation, in which the resulting structure is, from a diffraction point of view, indistinguishable from fluorite (AO2) (ref. 3). Shamblin et al. now reveal that the structure of disordered pyrochlore is more complicated than previously thought4.« less

  11. Complex oxides: Intricate disorder

    SciTech Connect

    Uberuaga, Blas Pedro

    2016-02-29

    In this study, complex oxides such as pyrochlores have a myriad of potential technological applications, including as fast ion conductors and radiation-tolerant nuclear waste forms. They are also of interest for their catalytic and spin ice properties. Many of these functional properties are enabled by the atomic structure of the cation sublattices. Pyrochlores (A2B2O7) contain two different cations (A and B), typically a 3+ rare earth and a 4+ transition metal such as Hf, Zr, or Ti. The large variety of chemistries that can form pyrochlores leads to a rich space in which to search for exotic new materials. Furthermore, how cations order or disorder on their respective sublattices for a given chemical composition influences the functional properties of the oxide. For example, oxygen ionic conductivity is directly correlated with the level of cation disorder — the swapping of A and B cations1. Further, the resistance of these materials against amorphization has also been connected with the ability of the cations to disorder2, 3. These correlations between cation structure and functionality have spurred great interest in the structure of the cation sublattice under irradiation, with significant focus on the disordering mechanisms and disordered structure. Previous studies have found that, upon irradiation, pyrochlores often undergo an order-to-disorder transformation, in which the resulting structure is, from a diffraction point of view, indistinguishable from fluorite (AO2) (ref. 3). Shamblin et al. now reveal that the structure of disordered pyrochlore is more complicated than previously thought4.

  12. Carney complex (CNC)

    PubMed Central

    Bertherat, Jérôme

    2006-01-01

    The Carney complex (CNC) is a dominantly inherited syndrome characterized by spotty skin pigmentation, endocrine overactivity and myxomas. Skin pigmentation anomalies include lentigines and blue naevi. The most common endocrine gland manifestations are acromegaly, thyroid and testicular tumors, and adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). PPNAD, a rare cause of Cushing's syndrome, is due to primary bilateral adrenal defect that can be also observed in some patients without other CNC manifestations or familial history of the disease. Myxomas can be observed in the heart, skin and breast. Cardiac myxomas can develop in any cardiac chamber and may be multiple. One of the putative CNC genes located on 17q22-24, (PRKAR1A), has been identified to encode the regulatory subunit (R1A) of protein kinase A. Heterozygous inactivating mutations of PRKAR1A were reported initially in 45 to 65 % of CNC index cases, and may be present in about 80 % of the CNC families presenting mainly with Cushing's syndrome. PRKAR1A is a key component of the cAMP signaling pathway that has been implicated in endocrine tumorigenesis and could, at least partly, function as a tumor suppressor gene. Genetic analysis should be proposed to all CNC index cases. Patients with CNC or with a genetic predisposition to CNC should have regular screening for manifestations of the disease. Clinical work-up for all the manifestations of CNC should be performed at least once a year in all patients and should start in infancy. Cardiac myxomas require surgical removal. Treatment of the other manifestations of CNC should be discussed and may include follow-up, surgery, or medical treatment depending on the location of the tumor, its size, the existence of clinical signs of tumor mass or hormonal excess, and the suspicion of malignancy. Bilateral adrenalectomy is the most common treatment for Cushing's syndrome due to PPNAD

  13. Spatiotemporal imaging of complexity

    PubMed Central

    Robinson, Stephen E.; Mandell, Arnold J.; Coppola, Richard

    2013-01-01

    What are the functional neuroimaging measurements required for more fully characterizing the events and locations of neocortical activity? A prime assumption has been that modulation of cortical activity will inevitably be reflected in changes in energy utilization (for the most part) changes of glucose and oxygen consumption. Are such a measures complete and sufficient? More direct measures of cortical electrophysiological activity show event or task-related modulation of amplitude or band-limited oscillatory power. Using magnetoencephalography (MEG), these measures have been shown to correlate well with energy utilization sensitive BOLD fMRI. In this paper, we explore the existence of state changes in electrophysiological cortical activity that can occur independently of changes in averaged amplitude, source power or indices of metabolic rates. In addition, we demonstrate that such state changes can be described by applying a new measure of complexity, rank vector entropy (RVE), to source waveform estimates from beamformer-processed MEG. RVE is a non-parametric symbolic dynamic informational entropy measure that accommodates the wide dynamic range of measured brain signals while resolving its temporal variations. By representing the measurements by their rank values, RVE overcomes the problem of defining embedding space partitions without resorting to signal compression. This renders RVE-independent of absolute signal amplitude. In addition, this approach is robust, being relatively free of tunable parameters. We present examples of task-free and task-dependent MEG demonstrating that RVE provides new information by uncovering hidden dynamical structure in the apparent turbulent (or chaotic) dynamics of spontaneous cortical activity. PMID:23355820

  14. Canine immune complex diseases.

    PubMed

    Plechner, A J

    1976-11-01

    Though not conclusive, our primary findings indicate that a feature common to many of our tumor and ICD patients is depressed cortisol production. Additionally, the response to ACTH adrenal cortex stimulation tests, at 2-hour intervals between rest and stimulation, have ranged from negative to substantially less than would be expected in normal subjects. Peripheral plasma cortisol values for dogs, at rest and 2 hours after ACTH stimulation, respectively, have been reported as 2-10 and 25-30 mug/dl, 3-8 and 7.5-18 mug/dl, and 1-12.5 and 9.5-22 mug/dl. For representative patients, our resting values have been 1.2-5.2 mug/dl, vs 1.2-7.6 mug after ACTH stimulation (Table 2). Altogether we have studied 42 cases in detail, and we feel that a post-ACTH level of 8.0 mug/dl or less is a conservative indication of adrenocortical insufficiency; all levels have been between 1 and 8 mug/dl. We believe these low cortisol levels indicate either a genetically-induced adrenal cortical insufficiency (evident at 2 months to 1 year of age) or an immune complex adrenal cortical suppression (occurring after 1 year of age in association with other immunodeficiency disorders). Our studies demonstrate a need for biphasic therapy. We have found it necessary to not only initiate cortisone acetate therapy to support the deficient adrenal cortical secretion, but also use other immunosuppressive drugs to control the ICD. If the target organ has been suppressed or destroyed, the need for supplementation is obvious. However, other immune-injury moieties must be suppressed also, eg, ANA, anti-IgG antibodies, etc.

  15. The hamstring muscle complex.

    PubMed

    van der Made, A D; Wieldraaijer, T; Kerkhoffs, G M; Kleipool, R P; Engebretsen, L; van Dijk, C N; Golanó, P

    2015-07-01

    The anatomical appearance of the hamstring muscle complex was studied to provide hypotheses for the hamstring injury pattern and to provide reference values of origin dimensions, muscle length, tendon length, musculotendinous junction (MTJ) length as well as width and length of a tendinous inscription in the semitendinosus muscle known as the raphe. Fifty-six hamstring muscle groups were dissected in prone position from 29 human cadaveric specimens with a median age of 71.5 (range 45-98). Data pertaining to origin dimensions, muscle length, tendon length, MTJ length and length as well as width of the raphe were collected. Besides these data, we also encountered interesting findings that might lead to a better understanding of the hamstring injury pattern. These include overlapping proximal and distal tendons of both the long head of the biceps femoris muscle and the semimembranosus muscle (SM), a twist in the proximal SM tendon and a tendinous inscription (raphe) in the semitendinosus muscle present in 96 % of specimens. No obvious hypothesis can be provided purely based on either muscle length, tendon length or MTJ length. However, it is possible that overlapping proximal and distal tendons as well as muscle architecture leading to a resultant force not in line with the tendon predispose to muscle injury, whereas the presence of a raphe might plays a role in protecting the muscle against gross injury. Apart from these architectural characteristics that may contribute to a better understanding of the hamstring injury pattern, the provided reference values complement current knowledge on surgically relevant hamstring anatomy. IV.

  16. Titan's chemical complexity

    NASA Astrophysics Data System (ADS)

    Vuitton, Veronique

    2012-04-01

    We review here our current knowledge of Titan's gas phase chemistry. We base our discussion on photochemical models as well as on laboratory experiments. We identify the lower mass positive [1,2] and negative [3] ions detected in the upper atmosphere and we show that their formation is a direct consequence of the presence of heavy neutrals. We demonstrate that the observed densities of CO, CO2 and H2O can be explained by a combination of exogenous O, and OH/H2O input [4]. We argue that benzene [5] and ammonia [6] are created in the upper atmosphere through complex chemical processes involving both neutral and ion chemistry. These species diffuse downward where they are at the origin of heavier aromatics and amines, respectively. Finally, we discuss the impact on hydrocarbon densities of recent theoretical calculations of the rate constants of association reactions [7]. [1] V. Vuitton, R. V. Yelle and V. G. Anicich, Astrophys. J., 647, L175 (2006). [2] V. Vuitton, R. V. Yelle and M. J. McEwan, Icarus, 191, 722 (2007). [3] V. Vuitton, P. Lavvas, R. V. Yelle, M. Galand, A. Wellbrock, G. R. Lewis, A. J. Coates and J.-E. Wahlund, Planet. Space Sci., 57, 1558 (2009). [4] S. M. Hörst, V. Vuitton, and R. V. Yelle, J. Geophys. Res., 113, E10006 (2008). [5] V. Vuitton, R. V. Yelle and J. Cui, J. Geophys. Res., 113, E05007 (2008). [6] R. V. Yelle, V. Vuitton, P. Lavvas, S. J. Klippenstein, M. A. Smith, S. M. Hörst and J. Cui, Faraday Discuss., 147, 31 (2010). [7] V. Vuitton, R. V. Yelle, S. J. Klippenstein and P. Lavvas, Astrophys. J., in press.

  17. Carney complex (CNC).

    PubMed

    Bertherat, Jérôme

    2006-06-06

    The Carney complex (CNC) is a dominantly inherited syndrome characterized by spotty skin pigmentation, endocrine overactivity and myxomas. Skin pigmentation anomalies include lentigines and blue naevi. The most common endocrine gland manifestations are acromegaly, thyroid and testicular tumors, and adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). PPNAD, a rare cause of Cushing's syndrome, is due to primary bilateral adrenal defect that can be also observed in some patients without other CNC manifestations or familial history of the disease. Myxomas can be observed in the heart, skin and breast. Cardiac myxomas can develop in any cardiac chamber and may be multiple. One of the putative CNC genes located on 17q22-24, (PRKAR1A), has been identified to encode the regulatory subunit (R1A) of protein kinase A. Heterozygous inactivating mutations of PRKAR1A were reported initially in 45 to 65% of CNC index cases, and may be present in about 80% of the CNC families presenting mainly with Cushing's syndrome. PRKAR1A is a key component of the cAMP signaling pathway that has been implicated in endocrine tumorigenesis and could, at least partly, function as a tumor suppressor gene. Genetic analysis should be proposed to all CNC index cases. Patients with CNC or with a genetic predisposition to CNC should have regular screening for manifestations of the disease. Clinical work-up for all the manifestations of CNC should be performed at least once a year in all patients and should start in infancy. Cardiac myxomas require surgical removal. Treatment of the other manifestations of CNC should be discussed and may include follow-up, surgery, or medical treatment depending on the location of the tumor, its size, the existence of clinical signs of tumor mass or hormonal excess, and the suspicion of malignancy. Bilateral adrenalectomy is the most common treatment for Cushing's syndrome due to PPNAD.

  18. Phonological Complexity and Language Learnability

    PubMed Central

    Gierut, Judith A.

    2008-01-01

    Purpose To extend formal models of language learnability to applications in clinical treatment of children with functional phonological delays. Method The focus of the narrative review is on phonological complexity. This follows from learnability theory, whereby complexity in the linguistic input to children has been shown to trigger language learning. Drawing from the literature, phonological complexity is defined from epistemic, ontological, and functional perspectives, with specific emphasis on the application of language universals in the selection of target sounds for treatment. Results The cascading effects of phonological complexity on children’s generalization learning are illustrated, and frequently asked questions about complexity in treatment are addressed. Conclusion The role of complexity in cognitive development is introduced to demonstrate the apparent robustness of effects. PMID:17329671

  19. Increasing complexity with quantum physics.

    PubMed

    Anders, Janet; Wiesner, Karoline

    2011-09-01

    We argue that complex systems science and the rules of quantum physics are intricately related. We discuss a range of quantum phenomena, such as cryptography, computation and quantum phases, and the rules responsible for their complexity. We identify correlations as a central concept connecting quantum information and complex systems science. We present two examples for the power of correlations: using quantum resources to simulate the correlations of a stochastic process and to implement a classically impossible computational task.

  20. Forecasting in Complex Systems

    NASA Astrophysics Data System (ADS)

    Rundle, J. B.; Holliday, J. R.; Graves, W. R.; Turcotte, D. L.; Donnellan, A.

    2014-12-01

    Complex nonlinear systems are typically characterized by many degrees of freedom, as well as interactions between the elements. Interesting examples can be found in the areas of earthquakes and finance. In these two systems, fat tails play an important role in the statistical dynamics. For earthquake systems, the Gutenberg-Richter magnitude-frequency is applicable, whereas for daily returns for the securities in the financial markets are known to be characterized by leptokurtotic statistics in which the tails are power law. Very large fluctuations are present in both systems. In earthquake systems, one has the example of great earthquakes such as the M9.1, March 11, 2011 Tohoku event. In financial systems, one has the example of the market crash of October 19, 1987. Both were largely unexpected events that severely impacted the earth and financial systems systemically. Other examples include the M9.3 Andaman earthquake of December 26, 2004, and the Great Recession which began with the fall of Lehman Brothers investment bank on September 12, 2013. Forecasting the occurrence of these damaging events has great societal importance. In recent years, national funding agencies in a variety of countries have emphasized the importance of societal relevance in research, and in particular, the goal of improved forecasting technology. Previous work has shown that both earthquakes and financial crashes can be described by a common Landau-Ginzburg-type free energy model. These metastable systems are characterized by fat tail statistics near the classical spinodal. Correlations in these systems can grow and recede, but do not imply causation, a common source of misunderstanding. In both systems, a common set of techniques can be used to compute the probabilities of future earthquakes or crashes. In this talk, we describe the basic phenomenology of these systems and emphasize their similarities and differences. We also consider the problem of forecast validation and verification

  1. Waves in complex systems

    NASA Astrophysics Data System (ADS)

    Xie, Hang

    The theme of this thesis is the study of wave phenomena in complex systems. In particular, the following three topics constitute the foci of my research. The first topic involves the generalization of an electronic transport mechanism commonly observed in disordered media, fluctuation induced tunneling conduction, by considering tunneling through not just insulating potential barriers, but also narrow conducting channels. Here the wave nature of the electron implies that a narrow conduction channel can act as an electronic waveguide, with a cutoff transverse dimension that is half the Fermi wavelength. My research involves the study of electronic transport through finite-length conducting channels with transverse dimensions below the cutoff. Such narrow conduction channel may be physically realized by chains of single conducting atoms, for example. At small voltage bias across the conduction channel, only tunneling transport is possible at zero temperature. But at finite temperatures some of the electrons with energies above the Fermi level can ballistically transport across the channel. By considering both tunneling and thermal activation mechanisms, with thermally-generated (random) voltage bias across the narrow channel, we obtained a temperature-dependent conductivity behavior that is in good agreement with the measured two-lead conductance of RuO2 and IrO2 nanowires. Furthermore, by considering high applied voltage across the nano conduction channels, our model predicts interesting electronic Fabry-Perot behavior whose experimental verification is presently underway. The second topic involves the study of the Hall effect in mesoscopic samples. In particular, we are interested in the possibility of enhancing the Hall effect by nano-patterning samples of 2D electron gas. Through numerical solution of the Schrodinger equation in the presence of a magnetic field, mesoscopic transport behavior is obtained for samples with given geometric patterns of the

  2. Complexity in de Sitter space

    NASA Astrophysics Data System (ADS)

    Reynolds, Alan P.; Ross, Simon F.

    2017-09-01

    We consider the holographic complexity conjectures for de-Sitter invariant states in a quantum field theory on de Sitter space, dual to asymptotically anti-de Sitter geometries with de Sitter boundaries. The bulk holographic duals include solutions with or without a horizon. If we compute the complexity from the spatial volume, we find results consistent with general expectations, but the conjectured bound on the growth rate is not saturated. If we compute complexity from the action of the Wheeler–de Witt patch, we find qualitative differences from the volume calculation, with states of smaller energy having larger complexity than those of larger energy, even though the latter have bulk horizons.

  3. Boron oxygen complexes in Si

    NASA Astrophysics Data System (ADS)

    Sanati, M.; Estreicher, S. K.

    2006-04-01

    The carrier lifetime in boron-doped Czochralski Si is strongly reduced by irradiation (space-based solar cells) or illumination (terrestrial cells). The culprits are believed to be boron-oxygen complexes. We use first-principles theory to predict the structure, electrical activity, and stability of complexes involving substitutional or interstitial B and interstitial O or oxygen dimers. Four complexes with comparable binding energies and thermodynamic gap levels are identified and their local vibrational modes predicted. Replacing B with Ga yields complexes with much smaller binding energies.

  4. Structural complexity of quantum networks

    SciTech Connect

    Siomau, Michael

    2016-06-10

    Quantum network is a set of nodes connected with channels, through which the nodes communicate photons and classical information. Classical structural complexity of a quantum network may be defined through its physical structure, i.e. mutual position of nodes and channels connecting them. We show here that the classical structural complexity of a quantum network does not restrict the structural complexity of entanglement graphs, which may be created in the quantum network with local operations and classical communication. We show, in particular, that 1D quantum network can simulate both simple entanglement graphs such as lattices and random graphs and complex small-world graphs.

  5. Technology and complexity: trouble brewing?

    PubMed

    Clancy, Thomas R

    2010-06-01

    As systems evolve over time, their natural tendency is to become increasingly more complex. Studies in the field of complex systems have generated new perspectives on management in social organizations such as hospitals. Much of this research appears as a natural extension of the cross-disciplinary field of systems theory. This is the 14th in a series of articles applying complex systems science to the traditional management concepts of planning, organizing, directing, coordinating, and controlling. This article focuses on new theories explaining growth in healthcare complexity, its effects on providers and patients, and solutions to manage it.

  6. Complex higher order derivative theories

    SciTech Connect

    Margalli, Carlos A.; Vergara, J. David

    2012-08-24

    In this work is considered a complex scalar field theory with higher order derivative terms and interactions. A procedure is developed to quantize consistently this system avoiding the presence of negative norm states. In order to achieve this goal the original real scalar high order field theory is extended to a complex space attaching a complex total derivative to the theory. Next, by imposing reality conditions the complex theory is mapped to a pair of interacting real scalar field theories without the presence of higher derivative terms.

  7. COMPLEX DIFFUSION ON IMAGE GRAPHS

    PubMed Central

    Seo, Dohyung; Vemuri, Baba C

    2009-01-01

    Complex diffusion was introduced in image processing literature as a means to achieve simultaneous denoising and enhancement of scalar valued images. In this paper, we present a novel geometric framework for achieving complex diffusion on color images expressed as image graphs. In this framework, we develop a new variational formulation for achieving complex diffusion. This formulation involves a modified harmonic map functional and is quite distinct from the Polyakov action described in earlier work by Sochen et al. Our formulation provides a framework for simultaneous (feature preserving) denoising and enhancement. We present results of comparison between the complex diffusion, and Beltrami flow all in the image graph framework. PMID:20490365

  8. The complexity of hierarchical systems

    NASA Astrophysics Data System (ADS)

    Ceccatto, H. A.; Huberman, B. A.

    1988-01-01

    We introduce a procedure for coarse graining a given hierarchical structure and show how it leads to an effective saturation of the complexity value with increasing number of lower levels. Secondly, we verify that this coarse grained measure has the property of isolating the most diverse trees as the ones with maximal complexity. As a corollary, we cast the dynamical measure of complexity of Bachas and Huberman in terms of purely static properties of trees representing ultradiffusion. We also discuss the differences between the coarse-grained measure of complexity and that provided by relaxation processes.

  9. New types of lanthanide complexes

    SciTech Connect

    Kahwa, I.A.K.

    1986-01-01

    Three new types of lanthanide (Ln) complexes, namely, the first examples of homodinuclear macrocyclic lanthanide complexes, novel binary and ternary gaseous polyatomic lanthanide oxides and new lanthanide oxalato complexes are described in chapters one, two and three respectively. The homodinuclear complexes are 2:2 condensation products of 2,6-diformyl-p-cresol and triethylenetetramine templated by Ln(NO/sub 3/)/sub 3/ and Ln(ClO/sub 4/)/sub 3/. The complexes are dimorphic, and are off-white (the more stable form) when they are obtained from dilute solutions and orange if they arise from more concentrated reactants. The complexes were characterized by elemental analysis, fast atom bombardment mass spectrometry (FAB MS), electronic absorption and IR spectroscopy, thermogravimetry along with preliminary spectroscopic studies using electron paramagnetic resonance, magnetic susceptibility and luminescence. The orange complexes exhibit more antiferromagnetic exchange interactions, low Ln/sup 3 +/magnetic moments and multi-exponential luminescence decay kinetics, whereas the off-white complexes show single exponential luminescence decay and free ion magnetic moments. At low temperatures and in presence of excess triethylenetetramine, solvated light lanthanide mononuclear complexes of a 1:1 acyclic Schiff base acetal were isolated and the structure of one of these was confirmed by single crystal x-ray diffraction crystallography.

  10. Quantitative assessment of increasing complexity

    NASA Astrophysics Data System (ADS)

    Csernai, L. P.; Spinnangr, S. F.; Velle, S.

    2017-05-01

    We study the build up of complexity on the example of 1 kg matter in different forms. We start with the simplest example of ideal gases, and then continue with more complex chemical, biological, life, social and technical structures. We assess the complexity of these systems quantitatively, based on their entropy. We present a method to attribute the same entropy to known physical systems and to complex organic molecules, up to a DNA molecule. The important steps in this program and the basic obstacles are discussed.

  11. Complexity leadership: a healthcare imperative.

    PubMed

    Weberg, Dan

    2012-01-01

    The healthcare system is plagued with increasing cost and poor quality outcomes. A major contributing factor for these issues is that outdated leadership practices, such as leader-centricity, linear thinking, and poor readiness for innovation, are being used in healthcare organizations. Complexity leadership theory provides a new framework with which healthcare leaders may practice leadership. Complexity leadership theory conceptualizes leadership as a continual process that stems from collaboration, complex systems thinking, and innovation mindsets. Compared to transactional and transformational leadership concepts, complexity leadership practices hold promise to improve cost and quality in health care. © 2012 Wiley Periodicals, Inc.

  12. Energy-Complexity Relations by Structural Complexity Methods

    NASA Astrophysics Data System (ADS)

    Ricca, Renzo L.

    2011-09-01

    In this paper we shall review some of the most recent developments and results on work on energy-complexity relations and, if time will allow it, we shall provide an analytical proof of eq. (3) below, a fundamental relation between energy and complexity established by numerical experiments.

  13. Complex Constructivism: A Theoretical Model of Complexity and Cognition

    ERIC Educational Resources Information Center

    Doolittle, Peter E.

    2014-01-01

    Education has long been driven by its metaphors for teaching and learning. These metaphors have influenced both educational research and educational practice. Complexity and constructivism are two theories that provide functional and robust metaphors. Complexity provides a metaphor for the structure of myriad phenomena, while constructivism…

  14. Sustainability, Complexity and Learning: Insights from Complex Systems Approaches

    ERIC Educational Resources Information Center

    Espinosa, A.; Porter, T.

    2011-01-01

    Purpose: The purpose of this research is to explore core contributions from two different approaches to complexity management in organisations aiming to improve their sustainability,: the Viable Systems Model (VSM), and the Complex Adaptive Systems (CAS). It is proposed to perform this by summarising the main insights each approach offers to…

  15. Sustainability, Complexity and Learning: Insights from Complex Systems Approaches

    ERIC Educational Resources Information Center

    Espinosa, A.; Porter, T.

    2011-01-01

    Purpose: The purpose of this research is to explore core contributions from two different approaches to complexity management in organisations aiming to improve their sustainability,: the Viable Systems Model (VSM), and the Complex Adaptive Systems (CAS). It is proposed to perform this by summarising the main insights each approach offers to…

  16. Societal Complexity and Familial Complexity: Evidence for the Curvilinear Hypothesis

    ERIC Educational Resources Information Center

    Blumberg, Rae Lesser; Winch, Robert F.

    1972-01-01

    The hypothesis is supported that the most extended, complex familial systems should be found among societies in an intermediate range of societal complexity, particularly among settled agricultural peoples. Among the simple hunting-gathering groups and in modern industrial states is found the nuclear family system: small, independent, nonextended…

  17. Competing Complexity Metrics and Adults' Production of Complex Sentences.

    ERIC Educational Resources Information Center

    Cheung, Hintat; Kemper, Susan

    1992-01-01

    Evaluation of the adequacy of 11 metrics for measuring linguistic complexity of language samples obtained from 60 to 90 year olds indicated that, although most of the metrics adequately accounted for age-group and individual differences in complexity, the amount and type of embedding proved to predict how easily sentences are understood and how…

  18. Tuberous sclerosis complex in autism.

    PubMed

    Guo, Xin; Tu, Wen-Jun; Shi, Xiao-Dong

    2012-09-01

    To study the prevalence rate of tuberous sclerosis complex in autistic disorder. We studied one cohort of children followed up since 2005 until 2009, with autistic disorder, to determine the incidence of tuberous sclerosis complex. We established an autistic disorder registry in 2005 at China Rehabilitation Research Center. During the 4-year period (2005-2009), we collected a database of 429 children (390 boys and 39 girls; male to female ratio 10:1) with autistic disorder and pervasive developmental disorders. We routinely examined all children with autistic disorder for any features of tuberous sclerosis complex by looking for neurocutaneous markers such as depigmented spots. In those with infantile spasm or epilepsy, the clinical features of tuberous sclerosis complex were monitored regularly during follow-up. Of these, five had tuberous sclerosis complex. Thus, the prevalence rate of tuberous sclerosis complex in autistic disorder is 1.17%. All of these children were mentally retarded with moderate to severe grades. Their IQ or developmental quotient was less than 70. The prevalence rate of tuberous sclerosis complex in autistic disorder was 1.17% in our region; autism spectrum disorder is a condition that might be associated with development of tuberous sclerosis complex.

  19. Teacher Knowledge: A Complex Tapestry

    ERIC Educational Resources Information Center

    Adoniou, Misty

    2015-01-01

    Teachers need to know a great deal, in many areas and in multiple ways. Teacher knowledge is a complex tapestry, and teachers must successfully weave the multiple threads. In this article, I present a conceptualisation of teacher knowledge that provides a framework for describing the complexity of teacher knowledge. The framework describes three…

  20. Syntactic Complexity and Cognitive Style.

    ERIC Educational Resources Information Center

    Kagan, Dona M.

    1980-01-01

    Describes two studies of which one analyzes syntactic complexity in writing samples by secondary and postsecondary students, while the other correlates the syntactic dimensions revealed by the former with measures of cognitive style. Correlations indicate an association between complexity and analytic cognitive style. (MES)

  1. COMPLEX MIXTURES AND GROUNDWATER QUALITY

    EPA Science Inventory

    Experience has shown that many soil and ground-water contamination problems involve complex mixtures of chemicals. his manuscript identifies and discusses, in a generic sense, some of the important processes which must be considered when dealing with complex mixtures in the subsu...

  2. Too Dumb for Complex Texts?

    ERIC Educational Resources Information Center

    Bauerlein, Mark

    2011-01-01

    High school students' lack of experience and practice with reading complex texts is a primary cause of their difficulties with college-level reading. Filling the syllabus with digital texts does little to address this deficiency. Complex texts demand three dispositions from readers: a willingness to probe works characterized by dense meanings, the…

  3. Phonological Complexity and Language Learnability

    ERIC Educational Resources Information Center

    Gierut, Judith A.

    2007-01-01

    Purpose: To extend formal models of language learnability to applications in clinical treatment of children with functional phonological delays. Method: The focus of the narrative review is on phonological complexity. This follows from learnability theory, whereby complexity in the linguistic input to children has been shown to trigger language…

  4. Classroom Management and Complex Instruction.

    ERIC Educational Resources Information Center

    Cohen, Elizabeth G.

    This paper illustrates how organizational theory can be usefully applied to issues of classroom management. A review of research findings on the relationship between the teacher's use of authority and the implementation and outcomes of "complex instruction" is offered. "Complex instruction" refers to instruction in which different groups carry out…

  5. A Simple Explanation of Complexation

    ERIC Educational Resources Information Center

    Elliott, J. Richard

    2010-01-01

    The topics of solution thermodynamics, activity coefficients, and complex formation are introduced through computational exercises and sample applications. The presentation is designed to be accessible to freshmen in a chemical engineering computations course. The MOSCED model is simplified to explain complex formation in terms of hydrogen…

  6. Teacher Knowledge: A Complex Tapestry

    ERIC Educational Resources Information Center

    Adoniou, Misty

    2015-01-01

    Teachers need to know a great deal, in many areas and in multiple ways. Teacher knowledge is a complex tapestry, and teachers must successfully weave the multiple threads. In this article, I present a conceptualisation of teacher knowledge that provides a framework for describing the complexity of teacher knowledge. The framework describes three…

  7. Improve Reading with Complex Texts

    ERIC Educational Resources Information Center

    Fisher, Douglas; Frey, Nancy

    2015-01-01

    The Common Core State Standards have cast a renewed light on reading instruction, presenting teachers with the new requirements to teach close reading of complex texts. Teachers and administrators should consider a number of essential features of close reading: They are short, complex texts; rich discussions based on worthy questions; revisiting…

  8. Complexity and Education: Vital Simultaneities

    ERIC Educational Resources Information Center

    Davis, Brent

    2008-01-01

    This article explores the place of complexity science within education and educational research. The discussion begins with the suggestion that educational research has a history of adopting interpretive frames from other domains with little adaptation. Complexity science is argued to compel a different sort of positioning, one that requires…

  9. Understanding and Teaching Complex Texts

    ERIC Educational Resources Information Center

    Fisher, Douglas; Frey, Nancy

    2014-01-01

    Teachers in today's classrooms struggle every day to design instructional interventions that would build students' reading skills and strategies in order to ensure their comprehension of complex texts. Text complexity can be determined in both qualitative and quantitative ways. In this article, the authors describe various innovative…

  10. Improve Reading with Complex Texts

    ERIC Educational Resources Information Center

    Fisher, Douglas; Frey, Nancy

    2015-01-01

    The Common Core State Standards have cast a renewed light on reading instruction, presenting teachers with the new requirements to teach close reading of complex texts. Teachers and administrators should consider a number of essential features of close reading: They are short, complex texts; rich discussions based on worthy questions; revisiting…

  11. Complexity and Education: Vital Simultaneities

    ERIC Educational Resources Information Center

    Davis, Brent

    2008-01-01

    This article explores the place of complexity science within education and educational research. The discussion begins with the suggestion that educational research has a history of adopting interpretive frames from other domains with little adaptation. Complexity science is argued to compel a different sort of positioning, one that requires…

  12. Complex Variables in Secondary Schools

    ERIC Educational Resources Information Center

    Dwyer, Jerry; Moskal, Barbara; Duke, Billy; Wilhelm, Jennifer

    2007-01-01

    This article describes the work of outreach mathematicians introducing the topic of complex variables to eighth and ninth grade students (13- to 15-year-olds) in the US. Complex variables is an area of mathematics that is not typically studied at secondary level. The authors developed seven lessons designed to stimulate students' interest in…

  13. Too Dumb for Complex Texts?

    ERIC Educational Resources Information Center

    Bauerlein, Mark

    2011-01-01

    High school students' lack of experience and practice with reading complex texts is a primary cause of their difficulties with college-level reading. Filling the syllabus with digital texts does little to address this deficiency. Complex texts demand three dispositions from readers: a willingness to probe works characterized by dense meanings, the…

  14. A Simple Explanation of Complexation

    ERIC Educational Resources Information Center

    Elliott, J. Richard

    2010-01-01

    The topics of solution thermodynamics, activity coefficients, and complex formation are introduced through computational exercises and sample applications. The presentation is designed to be accessible to freshmen in a chemical engineering computations course. The MOSCED model is simplified to explain complex formation in terms of hydrogen…

  15. Grammatical Complexity of Aphasic Speech.

    ERIC Educational Resources Information Center

    Kukkonen, Pirkko

    Spoken narratives as a genre usually show literary stylistic features. Written/literary registers are characterized by lexical density whereas spoken/colloquial genres are characterized by the complex combination of simple clauses into clause complexes. It has been observed that when aiming at informationally dense speech, people often hesitate…

  16. The Complexity of Language Learning

    ERIC Educational Resources Information Center

    Nelson, Charles

    2011-01-01

    This paper takes a complexity theory approach to looking at language learning, an approach that investigates how language learners adapt to and interact with people and their environment. Based on interviews with four graduate students, it shows how complexity theory can help us understand both the situatedness of language learning and also…

  17. The Algebra of Complex Numbers.

    ERIC Educational Resources Information Center

    LePage, Wilbur R.

    This programed text is an introduction to the algebra of complex numbers for engineering students, particularly because of its relevance to important problems of applications in electrical engineering. It is designed for a person who is well experienced with the algebra of real numbers and calculus, but who has no experience with complex number…

  18. The Evolution of Complex Life

    NASA Technical Reports Server (NTRS)

    Billingham, John

    1989-01-01

    In considering the probabilities that intelligent life might exist elsewhere in the Universe, it is important to ask questions about the factors governing the emergence of complex living organisms in the context of evolutionary biology, planetary environments and events in space. Two important problems arise. First, what can be learned about the general laws governing the evolution of complex life anywhere in space by studying its history on the Earth? Second, how is the evolution of complex life affected by events in space? To address these problems, a series of Science Workshops on the Evolution of Complex Life was held at the Ames Research Center. Included in this paper are highlights of those workshops, with particular emphasis on the first question, namely the evolution of complex extraterrestrial life.

  19. [Health: an adaptive complex system].

    PubMed

    Toro-Palacio, Luis Fernando; Ochoa-Jaramillo, Francisco Luis

    2012-02-01

    This article points out the enormous gap that exists between complex thinking of an intellectual nature currently present in our environment, and complex experimental thinking that has facilitated the scientific and technological advances that have radically changed the world. The article suggests that life, human beings, global society, and all that constitutes health be considered as adaptive complex systems. This idea, in turn, prioritizes the adoption of a different approach that seeks to expand understanding. When this rationale is recognized, the principal characteristics and emerging properties of health as an adaptive complex system are sustained, following a care and services delivery model. Finally, some pertinent questions from this perspective are put forward in terms of research, and a series of appraisals are expressed that will hopefully serve to help us understand all that we have become as individuals and as a species. The article proposes that the delivery of health care services be regarded as an adaptive complex system.

  20. The evolution of complex life.

    PubMed

    Billingham, J

    1989-01-01

    In considering the probabilities that intelligent life might exist elsewhere in the Universe, it is important to ask questions about the factors governing the emergence of complex living organisms in the context of evolutionary biology, planetary environments and events in space. Two important problems arise. First, what can be learned about the general laws governing the evolution of complex life anywhere in space by studying its history on the Earth? Second, how is the evolution of complex life affected by events in space? To address these problems, a series of Science Workshops on the Evolution of Complex Life was held at the Ames Research Center. Included in this paper are highlights of those workshops, with particular emphasis on the first question, namely the evolution of complex extraterrestrial life.

  1. Complex systems in metabolic engineering.

    PubMed

    Winkler, James D; Erickson, Keesha; Choudhury, Alaksh; Halweg-Edwards, Andrea L; Gill, Ryan T

    2015-12-01

    Metabolic engineers manipulate intricate biological networks to build efficient biological machines. The inherent complexity of this task, derived from the extensive and often unknown interconnectivity between and within these networks, often prevents researchers from achieving desired performance. Other fields have developed methods to tackle the issue of complexity for their unique subset of engineering problems, but to date, there has not been extensive and comprehensive examination of how metabolic engineers use existing tools to ameliorate this effect on their own research projects. In this review, we examine how complexity affects engineering at the protein, pathway, and genome levels within an organism, and the tools for handling these issues to achieve high-performing strain designs. Quantitative complexity metrics and their applications to metabolic engineering versus traditional engineering fields are also discussed. We conclude by predicting how metabolic engineering practices may advance in light of an explicit consideration of design complexity.

  2. Ternary complexes in analytical chemistry.

    PubMed

    Babko, A K

    1968-08-01

    Reactions between a complex AB and a third component C do not always proceed by a displacement mechanism governed by the energy difference of the chemical bonds A-B and A-C. The third component often becomes part of the complex, forming a mixed co-ordination sphere or ternary complex. The properties of this ternary complex ABC are not additive functions of the properties of AB and AC. Such reactions are important in many methods in analytical chemistry, particularly in photometric analysis, extractive separation, masking, etc. The general properties of the four basic types of ternary complex are reviewed and examples given. The four types comprise the systems (a) metal ion, electronegative ligand, organic base, (b) one metal ion, two different electronegative ligands, (c) ternary heteropoly acids, and (d) two different metal ions, one ligand.

  3. Complex Training: A Brief Review

    PubMed Central

    Ebben, William P.

    2002-01-01

    The effectiveness of plyometric training is well supported by research. Complex training has gained popularity as a training strategy combining weight training and plyometric training. Anecdotal reports recommend training in this fashion in order to improve muscular power and athletic performance. Recently, several studies have examined complex training. Despite the fact that questions remain about the potential effectiveness and implementation of this type of training, results of recent studies are useful in guiding practitioners in the development and implementation of complex training programs. In some cases, research suggests that complex training has an acute ergogenic effect on upper body power and the results of acute and chronic complex training include improved jumping performance. Improved performance may require three to four minutes rest between the weight training and plyometrics sets and the use of heavy weight training loads. PMID:24688269

  4. Intermittency in Complex Flows

    NASA Astrophysics Data System (ADS)

    Ben Mahjoub, Otman; Redondo, Jose M.

    2017-04-01

    Experimental results of the complex turbulent wake of a cilinder in 2D [1] and 3D flows [2] were used to investigate the scaling of structure functions, similar research was also performed on wave propagation and breaking in the Ocean [3], in the the stratified Atmosphere (ABL) [4] and in a 100large flume (UPC) for both regular and irregular waves, where long time series of waves propagating and generating breaking turbulence velocity rms and higher order measurements were taken in depth. [3,5] by means of a velocimeter SONTEK3-D. The probability distribution functions of the velocity differences and their non Gaussian distribution related to the energy spectrum indicate that irregularity is an important source of turbulence. From Kolmogorov's K41 and K61 intermittency correction: the p th-order longitudinal velocity structure function δul at scale l in the inertial range of three-dimensional fully developed turbulence is related by ⟨δup⟩ = ⟨(u(x+ l)- u(x))p⟩ ˜ ɛp0/3lp/3 l where ⟨...⟩ represents the spatial average over flow domain, with ɛ0 the mean energy dissipation per unit mass and l is the separation distance. The importance of the random nature of the energy dissipation led to the K62 theory of intermittency, but locality and non-homogeneity are key issues. p p/3 p/3 ξd ⟨δul⟩ ˜ ⟨ɛl ⟩l ˜ l and ξp = p 3 + τp/3 , where now ɛl is a fractal energy dissipation at scale l, τp/3 is the scaling of < ɛℓp/3 > and ξp is the scaling exponent of the velocity structure function of order p. Both in K41 and K62, the structure functions of third order related to skewness is ξ3 = 1. But this is not true either. We show that scaling exponents ξp do deviate from early studies that only investigated homogeneous turbulence, where a large inertial range dominates. The use of multi-fractal analysis and improvements on Structure function calculations on standard Enhanced mixing is an essential property of turbulence and efforts to alter and to

  5. [Genotyping of Cryptococcus neoformans/Cryptococcus gattii complex clinical isolates from Hospital "Dr. Julio C. Perrando", Resistencia city (Chaco, Argentina)].

    PubMed

    Cattana, Maria E; Tracogna, Maria F; Fernández, Mariana S; Carol Rey, Mariana C; Sosa, Maria A; Giusiano, Gustavo E

    2013-01-01

    Cryptococcosis is a fungal infection caused by yeast species of Cryptococcus genus, particularly Cryptococcus neoformans/Cryptococcus gattii species complex. The knowledge of the cryptococcosis casuistic in northeastern Argentina is scarce and there is no information about the molecular types circulating in this area. The aim of this study was to genotyping C. neoformans/C. gattii complex clinical isolates obtained at Hospital "Dr. Julio C. Perrando", Resistencia city (Chaco, Argentina), in order to determine species, variety and molecular type. During two years and one month 26 clinical isolates were studied. Using conventional and molecular methods one isolate was identified as C. gattii VGI type, and 25 isolates as C. neoformans var. grubii; 23 of these belonged to VNI type and two belonged to VNII type. This data is a contribution to the knowledge of cryptococcosis epidemiology in Argentina and the first report about C. neoformans/ C. gattii complex molecular types from clinical isolates in northeastern Argentina.

  6. Cancer complexity and radiation protection.

    PubMed

    Mossman, Kenneth L

    2014-07-01

    Management of radiological risks typically encountered in environmental and occupational settings is challenging because of uncertainties in the magnitude of the risks and the benefits of risk reduction. In practice, radiation dose instead of risk is measured. However, the relationship between dose and risk is not straightforward because cancer (the major health effect of concern at low doses) is a disease of complexity. Risks at small doses (defined as less than 100 mSv) can never be known exactly because of the inherent uncertainties in cancer as a complex disease. Tumors are complex because of the nonlinear interactions that occur among tumor cells and between the tumor and its local tissue environment. This commentary reviews evidence for cancer complexity and what complexity means for radiation protection. A complexity view of cancer does not mean we must abandon our current system of protection. What it does mean is that complexity requires new ways of thinking about control of cancer-the ideas that cancers can occur without cause, cancers behave unpredictably, and calculated cancer risks following small doses of radiation are highly uncertain.

  7. Solar active region magnetic complexity

    NASA Astrophysics Data System (ADS)

    Nikbakhsh, Shabnam; Tanskanen, Eija; Hackman, Thomas

    2017-04-01

    We have studied the Mount Wilson Classification of solar Active Regions (ARs) for the period from 1996 to 2015. Sunspots are visual indicators of ARs where the solar magnetic field is disturbed. Major manifestations of solar magnetic activity, such as solar flares and Coronal Mass Ejections (CMEs), are associated with solar ARs. There has been so many attempts to classify solar ARs based on their magnetic complexity as a measure of their acitivity. For this study we applied the Mount Wilson Classification which groups ARs in terms of their magnetic complexity from the least complex alpha to the most complex one beta-gamma-delta. We compared the magnetic complexity data to two sets of sunspot number: 1- International Sunspot Number (ISSN) 2- NOAA sunspot number We have been found that the number of more complex structures reach its maximum two years after solar maximum. We also compared the result to our identified geomagnetic storm list. The results showed the more complex ARs are responsible for the strongest geomagnetic storms.

  8. Kinetics of actinide complexation reactions

    SciTech Connect

    Nash, K.L.; Sullivan, J.C.

    1997-09-01

    Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions.

  9. The complexity of anatomical systems

    PubMed Central

    Grizzi, Fabio; Chiriva-Internati, Maurizio

    2005-01-01

    Background The conception of anatomical entities as a hierarchy of infinitely graduated forms and the increase in the number of observed anatomical sub-entities and structural variables has generated a growing complexity, thus highlighting new properties of organised biological matter. Results (1) Complexity is so pervasive in the anatomical world that it has come to be considered as a primary characteristic of anatomical systems. (2) Anatomical entities, when viewed at microscopic as well as macroscopic level of observation, show a different degree of complexity. (3) Complexity can reside in the structure of the anatomical system (having many diverse parts with varying interactions or an intricate architecture) or in its behaviour. Often complexity in structure and behaviour go together. (4) Complex systems admit many descriptions (ways of looking at the system) each of which is only partially true. Each way of looking at a complex system requires its own description, its own mode of analysis and its own breaking down of the system in different parts; (5) Almost all the anatomical entities display hierarchical forms: their component structures at different spatial scales or their process at different time scales are related to each other. Conclusion The need to find a new way of observing and measuring anatomical entities, and objectively quantifying their different structural changes, prompted us to investigate the non-Euclidean geometries and the theories of complexity, and to apply their concepts to human anatomy. This attempt has led us to reflect upon the complex significance of the shape of an observed anatomical entity. Its changes have been defined in relation to variations in its status: from a normal (i.e. natural) to a pathological or altered state introducing the concepts of kinematics and dynamics of anatomical forms, speed of their changes, and that of scale of their observation. PMID:16029490

  10. Quantum Tunneling and Complex Trajectories

    NASA Astrophysics Data System (ADS)

    Meynig, Max; Haggard, Hal

    2017-01-01

    In general, the semiclassical approximation of quantum mechanical tunneling fails to treat tunneling through barriers if real initial conditions and trajectories are used. By analytically continuing classical dynamics to the complex plane the problems encountered in the approximation can be resolved. While, the complex methods discussed here have been previously explored, no one has exhibited an analytically solvable case. The essential features of the complex method will be discussed in the context of a novel, analytically solvable problem. These methods could be useful in quantum gravity, with applications to the tunneling of spacetime geometries.

  11. [Carney's Complex: familial cardiac myxoma].

    PubMed

    Guerra, Miguel S; Santos, Nelson; Neves, Fátima; Carlos Mota, João; Miranda, José António; Vouga, Luis

    2006-01-01

    The Carney Complex is a very rare autosomal dominant disease including multiple neoplasia syndrome. This syndrome was initially described in 1985 under the rubric "...the complex of myxomas, spotty pigmentation, and endocrine overactivity". We present a case report of an old woman with Carney Complex who had the characteristic features of facial hirsutism and acromegalic facies, a large pigmented swelling over the face and a cardiac myxoma arising from the left atrium. We emphasize the need for periodic echocardiographic screening of patients and family members.

  12. The energetics of genome complexity.

    PubMed

    Lane, Nick; Martin, William

    2010-10-21

    All complex life is composed of eukaryotic (nucleated) cells. The eukaryotic cell arose from prokaryotes just once in four billion years, and otherwise prokaryotes show no tendency to evolve greater complexity. Why not? Prokaryotic genome size is constrained by bioenergetics. The endosymbiosis that gave rise to mitochondria restructured the distribution of DNA in relation to bioenergetic membranes, permitting a remarkable 200,000-fold expansion in the number of genes expressed. This vast leap in genomic capacity was strictly dependent on mitochondrial power, and prerequisite to eukaryote complexity: the key innovation en route to multicellular life.

  13. Complex Topographic Feature Ontology Patterns

    USGS Publications Warehouse

    Varanka, Dalia E.; Jerris, Thomas J.

    2015-01-01

    Semantic ontologies are examined as effective data models for the representation of complex topographic feature types. Complex feature types are viewed as integrated relations between basic features for a basic purpose. In the context of topographic science, such component assemblages are supported by resource systems and found on the local landscape. Ontologies are organized within six thematic modules of a domain ontology called Topography that includes within its sphere basic feature types, resource systems, and landscape types. Context is constructed not only as a spatial and temporal setting, but a setting also based on environmental processes. Types of spatial relations that exist between components include location, generative processes, and description. An example is offered in a complex feature type ‘mine.’ The identification and extraction of complex feature types are an area for future research.

  14. Complex bile duct injuries: management

    PubMed Central

    Ardiles, V.; Pekolj, J.

    2008-01-01

    Background. Laparoscopic cholecystectomy is the present treatment of choice for patients with gallbladder stones, despite its being associated with a higher incidence of biliary injuries compared with the open procedure. Injuries occurring during the laparoscopic approach seem to be more complex. A complex biliary injury is a disease that is difficult to diagnose and treat. We considered complex injuries: 1) injuries that involve the confluence; 2) injuries in which repair attempts have failed; 3) any bile duct injury associated with a vascular injury; 4) or any biliary injury in association with portal hypertension or secondary biliary cirrhosis. The present review is an evaluation of our experience in the treatment of these complex biliary injuries and an analysis of the international literature on the management of patients. PMID:18695753

  15. Mathematicians, Attributional Complexity, and Gender

    NASA Astrophysics Data System (ADS)

    Stalder, Daniel R.

    Given indirect indications in sex role and soda! psychology research that mathematical-deductive reasoning may negatively relate to social acuity, Study 1 investigated whether mathematicians were less attributionally complex than nonmathematicians. Study 1 administered the Attributional Complexity Scale, a measure of social acuity, to female and male faculty members and graduate students in four Midwestern schools. Atlrihutional complexity (AC) is the ability and motivation to give complex explanations for behavior. Study 1 found a significant interaction between field and gender. Only among women did mathematicians score lower on AC. In addition, an established gender difference in AC (that women score higher than men) was present only among nonmathematicians. Studies 2 and 3 offered some preliminary support for the possibility that it is generally female students who score tow on AC who aspire to he mathematicians and for the underlying view that female students' perceived similarity to mathematicians can influence their vocational choices.

  16. Complex Hydrides for Hydrogen Storage

    SciTech Connect

    Slattery, Darlene; Hampton, Michael

    2003-03-10

    This report describes research into the use of complex hydrides for hydrogen storage. The synthesis of a number of alanates, (AIH4) compounds, was investigated. Both wet chemical and mechano-chemical methods were studied.

  17. Making the Tent Function Complex

    ERIC Educational Resources Information Center

    Sprows, David J.

    2010-01-01

    This note can be used to illustrate to the student such concepts as periodicity in the complex plane. The basic construction makes use of the Tent function which requires only that the student have some working knowledge of binary arithmetic.

  18. Making the Tent Function Complex

    ERIC Educational Resources Information Center

    Sprows, David J.

    2010-01-01

    This note can be used to illustrate to the student such concepts as periodicity in the complex plane. The basic construction makes use of the Tent function which requires only that the student have some working knowledge of binary arithmetic.

  19. Synchronization in uncertain complex networks

    NASA Astrophysics Data System (ADS)

    Chen, Maoyin; Zhou, Donghua

    2006-03-01

    We consider the problem of synchronization in uncertain generic complex networks. For generic complex networks with unknown dynamics of nodes and unknown coupling functions including uniform and nonuniform inner couplings, some simple linear feedback controllers with updated strengths are designed using the well-known LaSalle invariance principle. The state of an uncertain generic complex network can synchronize an arbitrary assigned state of an isolated node of the network. The famous Lorenz system is stimulated as the nodes of the complex networks with different topologies. We found that the star coupled and scale-free networks with nonuniform inner couplings can be in the state of synchronization if only a fraction of nodes are controlled.

  20. Synchronization in uncertain complex networks.

    PubMed

    Chen, Maoyin; Zhou, Donghua

    2006-03-01

    We consider the problem of synchronization in uncertain generic complex networks. For generic complex networks with unknown dynamics of nodes and unknown coupling functions including uniform and nonuniform inner couplings, some simple linear feedback controllers with updated strengths are designed using the well-known LaSalle invariance principle. The state of an uncertain generic complex network can synchronize an arbitrary assigned state of an isolated node of the network. The famous Lorenz system is stimulated as the nodes of the complex networks with different topologies. We found that the star coupled and scale-free networks with nonuniform inner couplings can be in the state of synchronization if only a fraction of nodes are controlled.

  1. Bushveld Igneous Complex, South Africa

    NASA Image and Video Library

    2013-02-08

    The Bushveld Igneous Complex BIC is a large layered igneous intrusion within the earth crust, exposed at the edge of the Transvaal Basin in South Africa. Numerous mines, tailings piles, and leach ponds are shown in blue.

  2. SDO: Complex Mass of Plasma

    NASA Image and Video Library

    A small, but complex mass of solar material gyrated and spun about over the course of 40 hours above the surface of the sun on Sept. 1-3, 2015. It was stretched and pulled back and forth by powerfu...

  3. The future of complexity engineering

    NASA Astrophysics Data System (ADS)

    Frei, Regina; Di Marzo Serugendo, Giovanna

    2012-06-01

    Complexity Engineering encompasses a set of approaches to engineering systems which are typically composed of various interacting entities often exhibiting self-* behaviours and emergence. The engineer or designer uses methods that benefit from the findings of complexity science and often considerably differ from the classical engineering approach of "divide and conquer". This article provides an overview on some very interdisciplinary and innovative research areas and projects in the field of Complexity Engineering, including synthetic biology, chemistry, artificial life, self-healing materials and others. It then classifies the presented work according to five types of nature-inspired technology, namely: (1) using technology to understand nature, (2) nature-inspiration for technology, (3) using technology on natural systems, (4) using biotechnology methods in software engineering, and (5) using technology to model nature. Finally, future trends in Complexity Engineering are indicated and related risks are discussed.

  4. Unitarity and Complex Mass Fields

    NASA Astrophysics Data System (ADS)

    Bollini, C. G.; Oxman, L. E.

    We consider a field obeying a simple higher order equation with a real mass and two complex conjugate mass parameters. The evaluation of vacuum expectation values leads to the propagators, which are (resp.) a Feynman causal function and two complex conjugate Wheeler-Green functions (half retarded plus half advanced). By means of the computation of convolutions, we are able to show that the total self-energy has an absorptive part which is only due to the real mass. In this way it is shown that this diagram is compatible with unitarity and the elimination of free complex-mass asymptotic states from the set of external legs of the S-matrix. It is also shown that the complex masses act as regulators of ultraviolet divergences.

  5. [Adsorption Properties of Fluorine onto Fulvic Acid-Bentonite Complex].

    PubMed

    Fang, Dun; Tian, Hua-jing; Ye, Xin; He, Ci-li; Dan, You-meng; Wei, Shi-yong

    2016-03-15

    Fulvic Acid-Bentonite (FA-BENT) complex was prepared using coprecipitation method, and basic properties of the complex and sorption properties of fluorine at different environmental conditions were studied. XRD results showed that the d₀₀₁ spacing of FA- BENT complex had no obvious change compared with the raw bentonite, although the diffraction peak intensity of smectite in FA-BENT complex reduced, and indicated that FA mainly existed as a coating on the external surface of bentonite. Some functional groups (such as C==O, −OH, etc. ) of FA were observed in FA-BENT FTIR spectra, thus suggesting ligand exchange-surface complexation between FA and bentonite. Higher initial pH values of the reaction system were in favor of the adsorption of fluorine onto FA-BENT, while the equilibrium capacity decreased with the increase of pH at initial pH ≥ 4.50. The adsorption of fluorine onto FA-BENT was also affected by ionic strength, and the main reason might be the "polarity" effect. The adsorption of fluorine onto FA-BENT followed pseudo-second-order kinetic model and was controlled by chemical process ( R² = 0.999 2). Compared with the Freundlich model, Langmuir model was apparently of a higher goodness of fit (R² > 0.994 9) for absorption of fluorine onto FA-BENT. Thermodynamic parameters indicated that the adsorption process of fluorine was an spontaneously endothermic reaction, and was an entropy-driven process (ΔH 32.57 kJ · mol⁻¹, ΔS 112.31 J · (mol · K)⁻¹, ΔG −0.65- −1.76 kJ · mol⁻¹).

  6. Symbolic Dynamics and Grammatical Complexity

    NASA Astrophysics Data System (ADS)

    Hao, Bai-Lin; Zheng, Wei-Mou

    The following sections are included: * Formal Languages and Their Complexity * Formal Language * Chomsky Hierarchy of Grammatical Complexity * The L-System * Regular Language and Finite Automaton * Finite Automaton * Regular Language * Stefan Matrix as Transfer Function for Automaton * Beyond Regular Languages * Feigenbaum and Generalized Feigenbaum Limiting Sets * Even and Odd Fibonacci Sequences * Odd Maximal Primitive Prefixes and Kneading Map * Even Maximal Primitive Prefixes and Distinct Excluded Blocks * Summary of Results

  7. Complexity, action, and black holes

    SciTech Connect

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-04-18

    In an earlier paper "Complexity Equals Action" we conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the `Wheeler-DeWitt' patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.

  8. Thermochemical Radii of Complex Ions

    NASA Astrophysics Data System (ADS)

    Roobottom, Helen K.; Jenkins, H. Donald B.; Passmore, Jack; Glasser, Leslie

    1999-11-01

    Using rectilinear correlations of lattice energy with the inverse cubic root of the volume per molecule of complex salts of type MX (1:1), M2X (2:1), and MX2 (1:2) we have generated a comprehensive self-consistent tabulation of more than 400 thermochemical radii for complex ions. These radii can be used in the Kapustinskii equation to generate lattice energies and also as ion size parameters.

  9. Complex Hybrid Inflation and Baryogenesis

    SciTech Connect

    Delepine, David; Martinez, Carlos; Urena-Lopez, L. Arturo

    2007-04-20

    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated with the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vacuum expectation value of the waterfall field, which is well constrained by diverse cosmological observations.

  10. Complexity, action, and black holes

    NASA Astrophysics Data System (ADS)

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-04-01

    Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the "Wheeler-DeWitt" patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.

  11. Evolving Complexity, Cognition, and Consciousness

    NASA Astrophysics Data System (ADS)

    Liljenström, H.

    2012-12-01

    All through the history of the universe there is an apparent tendency for increasing complexity, with the organization of matter in evermore elaborate and interactive systems. The living world in general, and the human brain in particular, provides the highest complexity known. It seems obvious that all of this complexity must be the result of physical, chemical and biological evolution, but it was only with Darwin that we began to get a scientific understanding of biological evolution. Darwinian principles are guiding in our understanding of such complex systems as the nervous system, but also for the evolution of human society and technology. Living organisms have to survive in a complex and changing environment. This implies response and adaption to environmental events and changes at several time scales. The interaction with the environment depends on the present state of the organism, as well as on previous experiences stored in its molecular and cellular structures. At a longer time scale, organisms can adapt to slow environmental changes, by storing information in the genetic material carried over from generation to generation. This phylogenetic learning is complemented by ontogenetic learning, which is adaptation at a shorter time scale, occuring in non-genetic structures. The evolution of a nervous system is a major transition in biological evolution and allows for an increasing capacity for information storage and processing, increasing chances of survival. Such neural knowledge processing, cognition, shows the same principal features as nonneural adaptive processes. Similarly, consciousness might appear, to different degrees, at different stages in evolution. Both cognition and consciousness depends critically on the organization and complexity of the organism. In this presentation, I will briefly discuss general principles for evolution of complexity, focussing on the evolution of the nervous system, which provides organisms with ever increasing

  12. Quantum complexity and negative curvature

    NASA Astrophysics Data System (ADS)

    Brown, Adam R.; Susskind, Leonard; Zhao, Ying

    2017-02-01

    As time passes, once simple quantum states tend to become more complex. For strongly coupled k -local Hamiltonians, this growth of computational complexity has been conjectured to follow a distinctive and universal pattern. In this paper we show that the same pattern is exhibited by a much simpler system—classical geodesics on a compact two-dimensional geometry of uniform negative curvature. This striking parallel persists whether the system is allowed to evolve naturally or is perturbed from the outside.

  13. Complex numbers in quantum theory

    NASA Astrophysics Data System (ADS)

    Maynard, Glenn

    In 1927, Nobel prize winning physicist, E. Schrodinger, in correspondence with Ehrenfest, wrote the following about the new theory: "What is unpleasant here, and indeed directly to be objected to, is the use of complex numbers. Psi is surely fundamentally a real function." This seemingly simple issue remains unexplained almost ninety years later. In this dissertation I elucidate the physical and theoretical origins of the complex requirement. (Abstract shortened by ProQuest.).

  14. Complexity, action, and black holes

    SciTech Connect

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-04-18

    In an earlier paper "Complexity Equals Action" we conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the `Wheeler-DeWitt' patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.

  15. Goldstone Deep Space Communication Complex

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Three 34m (110 ft.) diameter Beam Waveguide antennas located at the Goldstone Deep Space Communications Complex, situated in the Mojave Desert in California. This is one of three complexes which comprise NASA's Deep Space Network (DSN). The DSN provides radio communications for all of NASA's interplanetary spacecraft and is also utilized for radio astronomy and radar observations of the solar system and the universe.

  16. Septin pairs, a complex choreography.

    PubMed

    Ewers, Helge

    2011-06-13

    Septins form a filamentous collar at the mother-bud neck in budding yeast. In cytokinesis, this collar splits into two rings and the septin complexes undergo a dramatic reorientation. Using fluorescence polarization microscopy, DeMay et al. (2011. J. Cell Biol. doi:10.1083/jcb.201012143) now demonstrate that septin complexes assemble as paired filaments in vivo and reveal new insights into septin organization during cytokinesis.

  17. STUDY OF METAL FLUORINE COMPLEXES.

    DTIC Science & Technology

    spectroscopy. These series consisted of fluorotitanate complexes of formula TiF4.2(donor) and TiF5.(donor)(-), where donor represents an organic molecule... fluorotitanate complexes. The temperature dependence of the TiF4.2D spectra was also studied. The low infrared spectra of some SnF4.2D and TiF4.2D were also obtained. (Author)

  18. Determinants of Hospital Casemix Complexity

    PubMed Central

    Becker, Edmund R.; Steinwald, Bruce

    1981-01-01

    Using the Commission on Professional and Hospital Activities' Resource Need Index as a measure of casemix complexity, this paper examines the relative contributions of teaching commitment and other hospital characteristics, hospital service and insurer distributions, and area characteristics to variations in casemix complexity. The empirical estimates indicate that all three types of independent variables have a substantial influence. These results are discussed in light of recent casemix research as well as current policy implications. PMID:6799430

  19. Mixed real/complex factorization

    SciTech Connect

    Lima, L.T.G. . Dept. of Electrical Engineering); Martines, N.; Pinto, H.J.C.P. . Centro de Pesquisas de Energia Electrica)

    1993-02-01

    This paper describes a mixed real/complex sparse matrix factorization and solution scheme applied to a large matrix problem. Large system eigenanalysis and frequency domain methods will directly benefit from the proposed scheme, which can reduce both memory and CPU time requirements when compared to conventional complex-only solutions. The application in hand is the small signal electromechanical stability analysis of large power systems. The savings obtained are significant considering the CPU intensive nature of these matrix problems.

  20. Conforming Morse-Smale Complexes

    SciTech Connect

    Gyulassy, Attila; Gunther, David; Levine, Joshua A.; Tierny, Julien; Pascucci, Valerio

    2014-08-11

    Morse-Smale (MS) complexes have been gaining popularity as a tool for feature-driven data analysis and visualization. However, the quality of their geometric embedding and the sole dependence on the input scalar field data can limit their applicability when expressing application-dependent features. In this paper we introduce a new combinatorial technique to compute an MS complex that conforms to both an input scalar field and an additional, prior segmentation of the domain. The segmentation constrains the MS complex computation guaranteeing that boundaries in the segmentation are captured as separatrices of the MS complex. We demonstrate the utility and versatility of our approach with two applications. First, we use streamline integration to determine numerically computed basins/mountains and use the resulting segmentation as an input to our algorithm. This strategy enables the incorporation of prior flow path knowledge, effectively resulting in an MS complex that is as geometrically accurate as the employed numerical integration. Our second use case is motivated by the observation that often the data itself does not explicitly contain features known to be present by a domain expert. We introduce edit operations for MS complexes so that a user can directly modify their features while maintaining all the advantages of a robust topology-based representation.

  1. Formulation of Complex Action Theory

    NASA Astrophysics Data System (ADS)

    Nagao, K.; Nielsen, H. B.

    2011-12-01

    We formulate a complex action theory which includes operators of coordinate and momentum hat{q} and hat{p} being replaced with non-hermitian operators hat{q}_{new} and hat{p}_{new}, and their eigenstates | q >_{new} and | p >_{new} with complex eigenvalues q and p. Introducing a philosophy of keeping the analyticity in path integration variables, we define a modified set of complex conjugate, real and imaginary parts, hermitian conjugates and bras, and explicitly construct hat{q}_{new}, hat{p}_{new}, |q >_{new} and |p >_{new} by formally squeezing coherent states. We also pose a theorem on the relation between functions on the phase space and the corresponding operators. Only in our formalism can we describe a complex action theory or a real action theory with complex saddle points in the tunneling effect etc. in terms of bras and kets in the functional integral. Furthermore, in a system with a non-hermitian diagonalizable bounded Hamiltonian, we show that the mechanism to obtain a hermitian Hamiltonian after a long time development proposed in our paper [Prog. Theor. Phys. 125 (2011), 633] works also in the complex coordinate formalism. If the hermitian Hamiltonian is given in a local form, a conserved probability current density can be constructed with two kinds of wave functions.

  2. The Ndc80 complex bridges two Dam1 complex rings

    PubMed Central

    Kim, Jae ook; Zelter, Alex; Umbreit, Neil T; Bollozos, Athena; Riffle, Michael; Johnson, Richard; MacCoss, Michael J; Asbury, Charles L; Davis, Trisha N

    2017-01-01

    Strong kinetochore-microtubule attachments are essential for faithful segregation of sister chromatids during mitosis. The Dam1 and Ndc80 complexes are the main microtubule binding components of the Saccharomyces cerevisiae kinetochore. Cooperation between these two complexes enhances kinetochore-microtubule coupling and is regulated by Aurora B kinase. We show that the Ndc80 complex can simultaneously bind and bridge across two Dam1 complex rings through a tripartite interaction, each component of which is regulated by Aurora B kinase. Mutations in any one of the Ndc80p interaction regions abrogates the Ndc80 complex’s ability to bind two Dam1 rings in vitro, and results in kinetochore biorientation and microtubule attachment defects in vivo. We also show that an extra-long Ndc80 complex, engineered to space the two Dam1 rings further apart, does not support growth. Taken together, our work suggests that each kinetochore in vivo contains two Dam1 rings and that proper spacing between the rings is vital. DOI: http://dx.doi.org/10.7554/eLife.21069.001 PMID:28191870

  3. "Computational Modeling of Actinide Complexes"

    SciTech Connect

    Balasubramanian, K

    2007-03-07

    We will present our recent studies on computational actinide chemistry of complexes which are not only interesting from the standpoint of actinide coordination chemistry but also of relevance to environmental management of high-level nuclear wastes. We will be discussing our recent collaborative efforts with Professor Heino Nitsche of LBNL whose research group has been actively carrying out experimental studies on these species. Computations of actinide complexes are also quintessential to our understanding of the complexes found in geochemical, biochemical environments and actinide chemistry relevant to advanced nuclear systems. In particular we have been studying uranyl, plutonyl, and Cm(III) complexes are in aqueous solution. These studies are made with a variety of relativistic methods such as coupled cluster methods, DFT, and complete active space multi-configuration self-consistent-field (CASSCF) followed by large-scale CI computations and relativistic CI (RCI) computations up to 60 million configurations. Our computational studies on actinide complexes were motivated by ongoing EXAFS studies of speciated complexes in geo and biochemical environments carried out by Prof Heino Nitsche's group at Berkeley, Dr. David Clark at Los Alamos and Dr. Gibson's work on small actinide molecules at ORNL. The hydrolysis reactions of urnayl, neputyl and plutonyl complexes have received considerable attention due to their geochemical and biochemical importance but the results of free energies in solution and the mechanism of deprotonation have been topic of considerable uncertainty. We have computed deprotonating and migration of one water molecule from the first solvation shell to the second shell in UO{sub 2}(H{sub 2}O){sub 5}{sup 2+}, UO{sub 2}(H{sub 2}O){sub 5}{sup 2+}NpO{sub 2}(H{sub 2}O){sub 6}{sup +}, and PuO{sub 2}(H{sub 2}O){sub 5}{sup 2+} complexes. Our computed Gibbs free energy(7.27 kcal/m) in solution for the first time agrees with the experiment (7.1 kcal

  4. Restricted Complexity Framework for Nonlinear Adaptive Control in Complex Systems

    SciTech Connect

    Williams, Rube B.

    2004-02-04

    Control law adaptation that includes implicit or explicit adaptive state estimation, can be a fundamental underpinning for the success of intelligent control in complex systems, particularly during subsystem failures, where vital system states and parameters can be impractical or impossible to measure directly. A practical algorithm is proposed for adaptive state filtering and control in nonlinear dynamic systems when the state equations are unknown or are too complex to model analytically. The state equations and inverse plant model are approximated by using neural networks. A framework for a neural network based nonlinear dynamic inversion control law is proposed, as an extrapolation of prior developed restricted complexity methodology used to formulate the adaptive state filter. Examples of adaptive filter performance are presented for an SSME simulation with high pressure turbine failure to support extrapolations to adaptive control problems.

  5. Restricted Complexity Framework for Nonlinear Adaptive Control in Complex Systems

    NASA Astrophysics Data System (ADS)

    Williams, Rube B.

    2004-02-01

    Control law adaptation that includes implicit or explicit adaptive state estimation, can be a fundamental underpinning for the success of intelligent control in complex systems, particularly during subsystem failures, where vital system states and parameters can be impractical or impossible to measure directly. A practical algorithm is proposed for adaptive state filtering and control in nonlinear dynamic systems when the state equations are unknown or are too complex to model analytically. The state equations and inverse plant model are approximated by using neural networks. A framework for a neural network based nonlinear dynamic inversion control law is proposed, as an extrapolation of prior developed restricted complexity methodology used to formulate the adaptive state filter. Examples of adaptive filter performance are presented for an SSME simulation with high pressure turbine failure to support extrapolations to adaptive control problems.

  6. Fluoroquinolone-Gyrase-DNA Complexes

    PubMed Central

    Mustaev, Arkady; Malik, Muhammad; Zhao, Xilin; Kurepina, Natalia; Luan, Gan; Oppegard, Lisa M.; Hiasa, Hiroshi; Marks, Kevin R.; Kerns, Robert J.; Berger, James M.; Drlica, Karl

    2014-01-01

    DNA gyrase and topoisomerase IV control bacterial DNA topology by breaking DNA, passing duplex DNA through the break, and then resealing the break. This process is subject to reversible corruption by fluoroquinolones, antibacterials that form drug-enzyme-DNA complexes in which the DNA is broken. The complexes, called cleaved complexes because of the presence of DNA breaks, have been crystallized and found to have the fluoroquinolone C-7 ring system facing the GyrB/ParE subunits. As expected from x-ray crystallography, a thiol-reactive, C-7-modified chloroacetyl derivative of ciprofloxacin (Cip-AcCl) formed cross-linked cleaved complexes with mutant GyrB-Cys466 gyrase as evidenced by resistance to reversal by both EDTA and thermal treatments. Surprisingly, cross-linking was also readily seen with complexes formed by mutant GyrA-G81C gyrase, thereby revealing a novel drug-gyrase interaction not observed in crystal structures. The cross-link between fluoroquinolone and GyrA-G81C gyrase correlated with exceptional bacteriostatic activity for Cip-AcCl with a quinolone-resistant GyrA-G81C variant of Escherichia coli and its Mycobacterium smegmatis equivalent (GyrA-G89C). Cip-AcCl-mediated, irreversible inhibition of DNA replication provided further evidence for a GyrA-drug cross-link. Collectively these data establish the existence of interactions between the fluoroquinolone C-7 ring and both GyrA and GyrB. Because the GyrA-Gly81 and GyrB-Glu466 residues are far apart (17 Å) in the crystal structure of cleaved complexes, two modes of quinolone binding must exist. The presence of two binding modes raises the possibility that multiple quinolone-enzyme-DNA complexes can form, a discovery that opens new avenues for exploring and exploiting relationships between drug structure and activity with type II DNA topoisomerases. PMID:24497635

  7. Complexity analysis of angiogenesis vasculature

    NASA Astrophysics Data System (ADS)

    Mahadevan, Vijay; Tyrell, James A.; Tong, Ricky T.; Brown, Edward B.; Jain, Rakesh K.; Roysam, Badrinath

    2005-04-01

    Tumor vasculature has a high degree of irregularity as compared to normal vasculature. The quantification of the morphometric complexity in tumor images can be useful in diagnosis. Also, it is desirable in several other medical applications to have an automated complexity analysis to aid in diagnosis and prognosis under treatment. e.g. in diabetic retinopathy and in arteriosclerosis. In addition, prior efforts at segmentation of the tumor vasculature using matched filtering, template matching and splines have been hampered by the irregularity of these vessels. We try to solve both problems by introducing a novel technique for vessel detection, followed by a tracing-independent complexity analysis based on a combination of ideas. First, the vessel cross-sectional profile is modeled using a continuous and everywhere differentiable family of super-Gaussian curves. This family generates rectangular profiles that can accurately localize the vessel boundaries in microvasculature images. Second, a robust non-linear regression algorithm based on M-estimators is used to estimate the parameters that optimally characterize the vessel"s shape. A framework for the quantitative analysis of the complexity of the vasculature based on the vessel detection is presented. A set of measures that quantify the complexity are proposed viz. Squared Error, Entropy-based and Minimum Description Length-based Shape Complexities. They are completely automatic and can deal with complexities of the entire vessel unlike existing tortuousity measures which deal only with vessel centerlines. The results are validated using carefully constructed phantom and real image data with ground truth information from an expert observer.

  8. Building a complex complex: Assembly of mitochondrial respiratory chain complex I.

    PubMed

    Formosa, Luke E; Dibley, Marris G; Stroud, David A; Ryan, Michael T

    2017-08-07

    Mitochondrial complex I is the primary entry point for electrons into the electron transport chain, required for the bulk of cellular ATP production via oxidative phosphorylation. Complex I consists of 45 subunits, which are encoded by both nuclear and mitochondrial DNA. Currently, at least 15 assembly factors are known to be required for the complete maturation of complex I. Mutations in the genes encoding subunits and assembly factors lead to complex I deficiency, which can manifest as mitochondrial disease. The current model of complex I assembly suggests that the enzyme is built by the association of a set of smaller intermediate modules containing specific conserved core subunits and additional accessory subunits. Each module must converge in a spatially and temporally orchestrated fashion to allow assembly of the mature holoenzyme to occur. This review outlines the current understanding of complex I biogenesis, with an emphasis on the assembly factors that facilitate the building of this architectural giant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Synthetic Investigations Featuring Amidometallic Complexes

    NASA Astrophysics Data System (ADS)

    Cummins, Christopher Colin

    Chapters 1-3 describe results illustrating a new technique for synthesizing nanoclusters of metal sulfide semiconductors within block copolymer microdomains. The sulfides of divalent Zn, Cd, and Pb were considered. Block copolymers were prepared using living ring-opening metathesis polymerization techniques based on well-defined initiators such as Mo(NAr)(CHR)(OR)_2 (Ar = 2,6-C_6H_3 -i-Pr_2; R = t-Bu). Certain amidometallic complexes were prepared that were polymerized in a living fashion permitting block copolymer synthesis; the block copolymers were converted to films through static casting and the domain-confined amidometallic complexes served as precursors to metal sulfides. In the course of this research a preparative route to light-sensitive pentamethylcyclopentadienyl cadmium complexes was uncovered. This led in turn to a nanocluster synthesis in which a precursor complex such as ZnPh_2 or CdAr_2 (Ar = 3,5-C_6H_3 (CF_3)_2) was attached to the desired block copolymer by a dative link. It was possible to synthesize ZnS and CdS within block copolymers displaying various morphologies using this versatile methodology. Chapters 4-9 describe transition metal chemistry stemming from the application of a novel tetradentate, tris(amido) ligand system: (RNCH_2CH _2)_3N (R = Me_3 Si, (N_3N); R = t-BuMe _2Si, (N_3N ^'); R = Et_3Si, (N_3N^*]). A terminal monohydride complex, HTi (N _3N), was investigated with respect to cyclometallation and ethylene insertion chemistry. A series of trigonal monopyramidal complexes M (N_3N) ^') (M = Ti, V, Cr, Mn, and Fe) was synthesized; the rare TMP coordination geometry has not previously been encountered for early transition metal complexes. The chemistry of V (N_3 N) was studied extensively; chalcogenide atom and imido group transfer to V (N_3N) are facile processes that lead to a formal two-electron oxidation of vanadium and give rise to a terminal vanadium -element multiple bond. Starting from Fe (N_3 N^') it was possible to

  10. Complex systems: physics beyond physics

    NASA Astrophysics Data System (ADS)

    Holovatch, Yurij; Kenna, Ralph; Thurner, Stefan

    2017-03-01

    Complex systems are characterised by specific time-dependent interactions among their many constituents. As a consequence they often manifest rich, non-trivial and unexpected behaviour. Examples arise both in the physical and non-physical worlds. The study of complex systems forms a new interdisciplinary research area that cuts across physics, biology, ecology, economics, sociology, and the humanities. In this paper we review the essence of complex systems from a physicists' point of view, and try to clarify what makes them conceptually different from systems that are traditionally studied in physics. Our goal is to demonstrate how the dynamics of such systems may be conceptualised in quantitative and predictive terms by extending notions from statistical physics and how they can often be captured in a framework of co-evolving multiplex network structures. We mention three areas of complex-systems science that are currently studied extensively, the science of cities, dynamics of societies, and the representation of texts as evolutionary objects. We discuss why these areas form complex systems in the above sense. We argue that there exists plenty of new ground for physicists to explore and that methodical and conceptual progress is needed most.

  11. Control principles of complex systems

    NASA Astrophysics Data System (ADS)

    Liu, Yang-Yu; Barabási, Albert-László

    2016-07-01

    A reflection of our ultimate understanding of a complex system is our ability to control its behavior. Typically, control has multiple prerequisites: it requires an accurate map of the network that governs the interactions between the system's components, a quantitative description of the dynamical laws that govern the temporal behavior of each component, and an ability to influence the state and temporal behavior of a selected subset of the components. With deep roots in dynamical systems and control theory, notions of control and controllability have taken a new life recently in the study of complex networks, inspiring several fundamental questions: What are the control principles of complex systems? How do networks organize themselves to balance control with functionality? To address these questions here recent advances on the controllability and the control of complex networks are reviewed, exploring the intricate interplay between the network topology and dynamical laws. The pertinent mathematical results are matched with empirical findings and applications. Uncovering the control principles of complex systems can help us explore and ultimately understand the fundamental laws that govern their behavior.

  12. Chemical complexity in galactic nuclei

    NASA Astrophysics Data System (ADS)

    Martin-Pintado, Jesus

    2007-12-01

    In recent years our knowledge of the chemical complexity in the nuclei of galaxies has dramatically changed. Recent observations of the nucleus of the Milky Way, of the starburst galaxy NGC253 and of the ultraluminous infrared galaxy (ULIRG) Arp220 have shown large abundance of complex organic molecules believed to be formed on grains. The Galactic center appears to be the largest repository of complex organic molecule like aldehydes and alcohols in the galaxy. We also measure large abundance of methanol in starburst galaxies and in ULIRGs suggesting that complex organic molecules are also efficiently produced in the central region of galaxies with strong star formation activity. From the systematic observational studies of molecular abundance in regions dominated by different heating processes like shocks, UV radiation, X-rays and cosmic rays in the center of the Milky Way, we are opening the possibility of using chemistry as a diagnostic tool to study the highly obscured regions of galactic centers. The templates found in the nucleus of the Milky Way will be used to establish the main mechanisms driving the heating and the chemistry of the molecular clouds in galaxies with different type of activity. The role of grain chemistry in the chemical complexity observed in the center of galaxies will be also briefly discussed.

  13. Complex fuzzy soft expert sets

    NASA Astrophysics Data System (ADS)

    Selvachandran, Ganeshsree; Hafeed, Nisren A.; Salleh, Abdul Razak

    2017-04-01

    Complex fuzzy sets and its accompanying theory although at its infancy, has proven to be superior to classical type-1 fuzzy sets, due its ability in representing time-periodic problem parameters and capturing the seasonality of the fuzziness that exists in the elements of a set. These are important characteristics that are pervasive in most real world problems. However, there are two major problems that are inherent in complex fuzzy sets: it lacks a sufficient parameterization tool and it does not have a mechanism to validate the values assigned to the membership functions of the elements in a set. To overcome these problems, we propose the notion of complex fuzzy soft expert sets which is a hybrid model of complex fuzzy sets and soft expert sets. This model incorporates the advantages of complex fuzzy sets and soft sets, besides having the added advantage of allowing the users to know the opinion of all the experts in a single model without the need for any additional cumbersome operations. As such, this model effectively improves the accuracy of representation of problem parameters that are periodic in nature, besides having a higher level of computational efficiency compared to similar models in literature.

  14. Cortical complexity in cetacean brains.

    PubMed

    Hof, Patrick R; Chanis, Rebecca; Marino, Lori

    2005-11-01

    Cetaceans (dolphins, whales, and porpoises) have a long, dramatically divergent evolutionary history compared with terrestrial mammals. Throughout their 55-60 million years of evolution, cetaceans acquired a compelling set of characteristics that include echolocation ability (in odontocetes), complex auditory and communicative capacities, and complex social organization. Moreover, although cetaceans have not shared a common ancestor with primates for over 90 million years, they possess a set of cognitive attributes that are strikingly convergent with those of many primates, including great apes and humans. In contrast, cetaceans have evolved a highly unusual combination of neurobiological features different from that of primates. As such, cetacean brains offer a critical opportunity to address questions about how complex behavior can be based on very different neuroanatomical and neurobiological evolutionary products. Cetacean brains and primate brains are arguably most meaningfully conceived as alternative evolutionary routes to neurobiological and cognitive complexity. In this article, we summarize data on brain size and hemisphere surface configuration in several cetacean species and present an overview of the cytoarchitectural complexity of the cerebral cortex of the bottlenose dolphin.

  15. Photolithographic Encoding of Metal Complexes.

    PubMed

    Lang, Christiane; Bestgen, Sebastian; Welle, Alexander; Müller, Rouven; Roesky, Peter W; Barner-Kowollik, Christopher

    2015-10-12

    A platform technology for the creation of spatially resolved surfaces encoded with a monolayer consisting of different metal complexes was developed. The concept entails the light-triggered activation of a self- assembled monolayer (SAM) of UV-labile anchors, that is, phenacylsulfides, and the subsequent cycloaddition of selected diene-functionalized metal complexes at defined areas on the surface. The synthesis and characterization of the metal complexes for the UV-light assisted anchoring on the surface and a detailed study of a short-chain oligomer model system in solution confirm the high efficiency of the photoreaction. The hybrid materials obtained by this concept can potentially be utilized for the design of highly valuable catalytic or (opto-)electronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Emergence: complexity pedagogy in action.

    PubMed

    Jonas-Simpson, Christine; Mitchell, Gail; Cross, Nadine

    2015-01-01

    Many educators are looking for new ways to engage students and each other in order to enrich curriculum and the teaching-learning process. We describe an example of how we enacted teaching-learning approaches through the insights of complexity thinking, an approach that supports the emergence of new possibilities for teaching-learning in the classroom and online. Our story begins with an occasion to meet with 10 nursing colleagues in a three-hour workshop using four activities that engaged learning about complexity thinking and pedagogy. Guiding concepts for the collaborative workshop were nonlinearity, distributed decision-making, divergent thinking, self-organization, emergence, and creative exploration. The workshop approach considered critical questions to spark our collective inquiry. We asked, "What is emergent learning?" and "How do we, as educators and learners, engage a community so that new learning surfaces?" We integrated the arts, creative play, and perturbations within a complexity approach.

  17. Articulation points in complex networks

    NASA Astrophysics Data System (ADS)

    Tian, Liang; Bashan, Amir; Shi, Da-Ning; Liu, Yang-Yu

    2017-01-01

    An articulation point in a network is a node whose removal disconnects the network. Those nodes play key roles in ensuring connectivity of many real-world networks, from infrastructure networks to protein interaction networks and terrorist communication networks. Despite their fundamental importance, a general framework of studying articulation points in complex networks is lacking. Here we develop analytical tools to study key issues pertinent to articulation points, such as the expected number of them and the network vulnerability against their removal, in an arbitrary complex network. We find that a greedy articulation point removal process provides us a different perspective on the organizational principles of complex networks. Moreover, this process results in a rich phase diagram with two fundamentally different types of percolation transitions. Our results shed light on the design of more resilient infrastructure networks and the effective destruction of terrorist communication networks.

  18. Graph distance for complex networks

    NASA Astrophysics Data System (ADS)

    Shimada, Yutaka; Hirata, Yoshito; Ikeguchi, Tohru; Aihara, Kazuyuki

    2016-10-01

    Networks are widely used as a tool for describing diverse real complex systems and have been successfully applied to many fields. The distance between networks is one of the most fundamental concepts for properly classifying real networks, detecting temporal changes in network structures, and effectively predicting their temporal evolution. However, this distance has rarely been discussed in the theory of complex networks. Here, we propose a graph distance between networks based on a Laplacian matrix that reflects the structural and dynamical properties of networked dynamical systems. Our results indicate that the Laplacian-based graph distance effectively quantifies the structural difference between complex networks. We further show that our approach successfully elucidates the temporal properties underlying temporal networks observed in the context of face-to-face human interactions.

  19. Complex Fluids and Hydraulic Fracturing.

    PubMed

    Barbati, Alexander C; Desroches, Jean; Robisson, Agathe; McKinley, Gareth H

    2016-06-07

    Nearly 70 years old, hydraulic fracturing is a core technique for stimulating hydrocarbon production in a majority of oil and gas reservoirs. Complex fluids are implemented in nearly every step of the fracturing process, most significantly to generate and sustain fractures and transport and distribute proppant particles during and following fluid injection. An extremely wide range of complex fluids are used: naturally occurring polysaccharide and synthetic polymer solutions, aqueous physical and chemical gels, organic gels, micellar surfactant solutions, emulsions, and foams. These fluids are loaded over a wide range of concentrations with particles of varying sizes and aspect ratios and are subjected to extreme mechanical and environmental conditions. We describe the settings of hydraulic fracturing (framed by geology), fracturing mechanics and physics, and the critical role that non-Newtonian fluid dynamics and complex fluids play in the hydraulic fracturing process.

  20. Manipulating complex light with metamaterials.

    PubMed

    Zeng, Jinwei; Wang, Xi; Sun, Jingbo; Pandey, Apra; Cartwright, Alexander N; Litchinitser, Natalia M

    2013-10-02

    Recent developments in the field of metamaterials have revealed unparalleled opportunities for "engineering" space for light propagation; opening a new paradigm in spin- and quantum-related phenomena in optical physics. Here we show that unique optical properties of metamaterials (MMs) open unlimited prospects to "engineer" light itself. We propose and demonstrate for the first time a novel way of complex light manipulation in few-mode optical fibers using optical MMs. Most importantly, these studies highlight how unique properties of MMs, namely the ability to manipulate both electric and magnetic field components of electromagnetic (EM) waves, open new degrees of freedom in engineering complex polarization states of light at will, while preserving its orbital angular momentum (OAM) state. These results lay the first steps in manipulating complex light in optical fibers, likely providing new opportunities for high capacity communication systems, quantum information, and on-chip signal processing.

  1. Complexity matching in dyadic conversation.

    PubMed

    Abney, Drew H; Paxton, Alexandra; Dale, Rick; Kello, Christopher T

    2014-12-01

    Recent studies of dyadic interaction have examined phenomena of synchronization, entrainment, alignment, and convergence. All these forms of behavioral matching have been hypothesized to play a supportive role in establishing coordination and common ground between interlocutors. In the present study, evidence is found for a new kind of coordination termed complexity matching. Temporal dynamics in conversational speech signals were analyzed through time series of acoustic onset events. Timing in periods of acoustic energy was found to exhibit behavioral matching that reflects complementary timing in turn-taking. In addition, acoustic onset times were found to exhibit power law clustering across a range of timescales, and these power law functions were found to exhibit complexity matching that is distinct from behavioral matching. Complexity matching is discussed in terms of interactive alignment and other theoretical principles that lead to new hypotheses about information exchange in dyadic conversation and interaction in general.

  2. Articulation points in complex networks

    PubMed Central

    Tian, Liang; Bashan, Amir; Shi, Da-Ning; Liu, Yang-Yu

    2017-01-01

    An articulation point in a network is a node whose removal disconnects the network. Those nodes play key roles in ensuring connectivity of many real-world networks, from infrastructure networks to protein interaction networks and terrorist communication networks. Despite their fundamental importance, a general framework of studying articulation points in complex networks is lacking. Here we develop analytical tools to study key issues pertinent to articulation points, such as the expected number of them and the network vulnerability against their removal, in an arbitrary complex network. We find that a greedy articulation point removal process provides us a different perspective on the organizational principles of complex networks. Moreover, this process results in a rich phase diagram with two fundamentally different types of percolation transitions. Our results shed light on the design of more resilient infrastructure networks and the effective destruction of terrorist communication networks. PMID:28139697

  3. Characterising Complex Enzyme Reaction Data

    PubMed Central

    Rahman, Syed Asad; Thornton, Janet M.

    2016-01-01

    The relationship between enzyme-catalysed reactions and the Enzyme Commission (EC) number, the widely accepted classification scheme used to characterise enzyme activity, is complex and with the rapid increase in our knowledge of the reactions catalysed by enzymes needs revisiting. We present a manual and computational analysis to investigate this complexity and found that almost one-third of all known EC numbers are linked to more than one reaction in the secondary reaction databases (e.g., KEGG). Although this complexity is often resolved by defining generic, alternative and partial reactions, we have also found individual EC numbers with more than one reaction catalysing different types of bond changes. This analysis adds a new dimension to our understanding of enzyme function and might be useful for the accurate annotation of the function of enzymes and to study the changes in enzyme function during evolution. PMID:26840640

  4. Exact controllability of complex networks

    PubMed Central

    Yuan, Zhengzhong; Zhao, Chen; Di, Zengru; Wang, Wen-Xu; Lai, Ying-Cheng

    2013-01-01

    Controlling complex networks is of paramount importance in science and engineering. Despite the recent development of structural controllability theory, we continue to lack a framework to control undirected complex networks, especially given link weights. Here we introduce an exact controllability paradigm based on the maximum multiplicity to identify the minimum set of driver nodes required to achieve full control of networks with arbitrary structures and link-weight distributions. The framework reproduces the structural controllability of directed networks characterized by structural matrices. We explore the controllability of a large number of real and model networks, finding that dense networks with identical weights are difficult to be controlled. An efficient and accurate tool is offered to assess the controllability of large sparse and dense networks. The exact controllability framework enables a comprehensive understanding of the impact of network properties on controllability, a fundamental problem towards our ultimate control of complex systems. PMID:24025746

  5. Graph distance for complex networks

    PubMed Central

    Shimada, Yutaka; Hirata, Yoshito; Ikeguchi, Tohru; Aihara, Kazuyuki

    2016-01-01

    Networks are widely used as a tool for describing diverse real complex systems and have been successfully applied to many fields. The distance between networks is one of the most fundamental concepts for properly classifying real networks, detecting temporal changes in network structures, and effectively predicting their temporal evolution. However, this distance has rarely been discussed in the theory of complex networks. Here, we propose a graph distance between networks based on a Laplacian matrix that reflects the structural and dynamical properties of networked dynamical systems. Our results indicate that the Laplacian-based graph distance effectively quantifies the structural difference between complex networks. We further show that our approach successfully elucidates the temporal properties underlying temporal networks observed in the context of face-to-face human interactions. PMID:27725690

  6. Multi-stage complex contagions

    NASA Astrophysics Data System (ADS)

    Melnik, Sergey; Ward, Jonathan A.; Gleeson, James P.; Porter, Mason A.

    2013-03-01

    The spread of ideas across a social network can be studied using complex contagion models, in which agents are activated by contact with multiple activated neighbors. The investigation of complex contagions can provide crucial insights into social influence and behavior-adoption cascades on networks. In this paper, we introduce a model of a multi-stage complex contagion on networks. Agents at different stages—which could, for example, represent differing levels of support for a social movement or differing levels of commitment to a certain product or idea—exert different amounts of influence on their neighbors. We demonstrate that the presence of even one additional stage introduces novel dynamical behavior, including interplay between multiple cascades, which cannot occur in single-stage contagion models. We find that cascades—and hence collective action—can be driven not only by high-stage influencers but also by low-stage influencers.

  7. Multi-stage complex contagions.

    PubMed

    Melnik, Sergey; Ward, Jonathan A; Gleeson, James P; Porter, Mason A

    2013-03-01

    The spread of ideas across a social network can be studied using complex contagion models, in which agents are activated by contact with multiple activated neighbors. The investigation of complex contagions can provide crucial insights into social influence and behavior-adoption cascades on networks. In this paper, we introduce a model of a multi-stage complex contagion on networks. Agents at different stages-which could, for example, represent differing levels of support for a social movement or differing levels of commitment to a certain product or idea-exert different amounts of influence on their neighbors. We demonstrate that the presence of even one additional stage introduces novel dynamical behavior, including interplay between multiple cascades, which cannot occur in single-stage contagion models. We find that cascades-and hence collective action-can be driven not only by high-stage influencers but also by low-stage influencers.

  8. Complex Autocatalysis in Simple Chemistries.

    PubMed

    Virgo, Nathaniel; Ikegami, Takashi; McGregor, Simon

    2016-01-01

    Life on Earth must originally have arisen from abiotic chemistry. Since the details of this chemistry are unknown, we wish to understand, in general, which types of chemistry can lead to complex, lifelike behavior. Here we show that even very simple chemistries in the thermodynamically reversible regime can self-organize to form complex autocatalytic cycles, with the catalytic effects emerging from the network structure. We demonstrate this with a very simple but thermodynamically reasonable artificial chemistry model. By suppressing the direct reaction from reactants to products, we obtain the simplest kind of autocatalytic cycle, resulting in exponential growth. When these simple first-order cycles are prevented from forming, the system achieves superexponential growth through more complex, higher-order autocatalytic cycles. This leads to nonlinear phenomena such as oscillations and bistability, the latter of which is of particular interest regarding the origins of life.

  9. Manipulating Complex Light with Metamaterials

    PubMed Central

    Zeng, Jinwei; Wang, Xi; Sun, Jingbo; Pandey, Apra; Cartwright, Alexander N.; Litchinitser, Natalia M.

    2013-01-01

    Recent developments in the field of metamaterials have revealed unparalleled opportunities for “engineering” space for light propagation; opening a new paradigm in spin- and quantum-related phenomena in optical physics. Here we show that unique optical properties of metamaterials (MMs) open unlimited prospects to “engineer” light itself. We propose and demonstrate for the first time a novel way of complex light manipulation in few-mode optical fibers using optical MMs. Most importantly, these studies highlight how unique properties of MMs, namely the ability to manipulate both electric and magnetic field components of electromagnetic (EM) waves, open new degrees of freedom in engineering complex polarization states of light at will, while preserving its orbital angular momentum (OAM) state. These results lay the first steps in manipulating complex light in optical fibers, likely providing new opportunities for high capacity communication systems, quantum information, and on-chip signal processing. PMID:24084836

  10. Hilbert complexes of nonlinear elasticity

    NASA Astrophysics Data System (ADS)

    Angoshtari, Arzhang; Yavari, Arash

    2016-12-01

    We introduce some Hilbert complexes involving second-order tensors on flat compact manifolds with boundary that describe the kinematics and the kinetics of motion in nonlinear elasticity. We then use the general framework of Hilbert complexes to write Hodge-type and Helmholtz-type orthogonal decompositions for second-order tensors. As some applications of these decompositions in nonlinear elasticity, we study the strain compatibility equations of linear and nonlinear elasticity in the presence of Dirichlet boundary conditions and the existence of stress functions on non-contractible bodies. As an application of these Hilbert complexes in computational mechanics, we briefly discuss the derivation of a new class of mixed finite element methods for nonlinear elasticity.

  11. The Ontologies of Complexity and Learning about Complex Systems

    ERIC Educational Resources Information Center

    Jacobson, Michael J.; Kapur, Manu; So, Hyo-Jeong; Lee, June

    2011-01-01

    This paper discusses a study of students learning core conceptual perspectives from recent scientific research on complexity using a hypermedia learning environment in which different types of scaffolding were provided. Three comparison groups used a hypermedia system with agent-based models and scaffolds for problem-based learning activities that…

  12. The Ontologies of Complexity and Learning about Complex Systems

    ERIC Educational Resources Information Center

    Jacobson, Michael J.; Kapur, Manu; So, Hyo-Jeong; Lee, June

    2011-01-01

    This paper discusses a study of students learning core conceptual perspectives from recent scientific research on complexity using a hypermedia learning environment in which different types of scaffolding were provided. Three comparison groups used a hypermedia system with agent-based models and scaffolds for problem-based learning activities that…

  13. Complex Educational Design: A Course Design Model Based on Complexity

    ERIC Educational Resources Information Center

    Freire, Maximina Maria

    2013-01-01

    Purpose: This article aims at presenting a conceptual framework which, theoretically grounded on complexity, provides the basis to conceive of online language courses that intend to respond to the needs of students and society. Design/methodology/approach: This paper is introduced by reflections on distance education and on the paradigmatic view…

  14. 1998 Complex Systems Summer School

    SciTech Connect

    1998-12-15

    For the past eleven years a group of institutes, centers, and universities throughout the country have sponsored a summer school in Santa Fe, New Mexico as part of an interdisciplinary effort to promote the understanding of complex systems. The goal of these summer schools is to provide graduate students, postdoctoral fellows and active research scientists with an introduction to the study of complex behavior in mathematical, physical, and living systems. The Center for Nonlinear Studies supported the eleventh in this series of highly successful schools in Santa Fe in June, 1998.

  15. Matrix Fourth-Complex Variables

    NASA Astrophysics Data System (ADS)

    Dimiev, Stancho; Marinov, Marin S.; Stoev, Peter

    2009-11-01

    In the paper we consider quasi-cyclic hyper-complex variables which are naturally related to the partial differential equations with complex variables. In fact, we develop a matrix 4×4 generalization of the classical bicomplex numbers [1], [2]. We recall that a matrix 2×2 isomorphic type treatment of the classical bicomplex numbers was developed in [3]. Here we develop a matrix 4×4 generalization of the bicomplex numbers including some improvement of the papers [3] and [4]. Let us remark that a deep generalization of the considered ideas was sketch in [5] before us.

  16. Holographic Complexity Equals Bulk Action?

    NASA Astrophysics Data System (ADS)

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-05-01

    We conjecture that the quantum complexity of a holographic state is dual to the action of a certain spacetime region that we call a Wheeler-DeWitt patch. We illustrate and test the conjecture in the context of neutral, charged, and rotating black holes in anti-de Sitter spacetime, as well as black holes perturbed with static shells and with shock waves. This conjecture evolved from a previous conjecture that complexity is dual to spatial volume, but appears to be a major improvement over the original. In light of our results, we discuss the hypothesis that black holes are the fastest computers in nature.

  17. Silver Complexes of Dihalogen Molecules.

    PubMed

    Malinowski, Przemysław J; Himmel, Daniel; Krossing, Ingo

    2016-08-01

    The perfluorohexane-soluble and donor-free silver compound Ag(A) (A=Al(OR(F) )4 ; R(F) =C(CF3 )3 ) prepared using a facile novel route has unprecedented capabilities to form unusual and weakly bound complexes. Here, we report on the three dihalogen-silver complexes Ag(Cl2 )A, Ag(Br2 )A, and Ag(I2 )A derived from the soluble silver compound Ag(A) (characterized by single-crystal/powder XRD, Raman spectra, and quantum-mechanical calculations). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Correlation dimension of complex networks.

    PubMed

    Lacasa, Lucas; Gómez-Gardeñes, Jesús

    2013-04-19

    We propose a new measure to characterize the dimension of complex networks based on the ergodic theory of dynamical systems. This measure is derived from the correlation sum of a trajectory generated by a random walker navigating the network, and extends the classical Grassberger-Procaccia algorithm to the context of complex networks. The method is validated with reliable results for both synthetic networks and real-world networks such as the world air-transportation network or urban networks, and provides a computationally fast way for estimating the dimensionality of networks which only relies on the local information provided by the walkers.

  19. Multiscale simulation of complex coacervates

    NASA Astrophysics Data System (ADS)

    Hoffmann, Kyle Q.; Whitmer, Jonathan K.; Qin, Jian; Priftis, Dimitris; Perry, Sarah; Leon, Lorraine; Kade, Matthew; Tirrell, Matthew; de Pablo, Juan J.

    2014-03-01

    Aqueous solutions of polymers having opposite charge can separate into a coacervate phase and a supernatant water phase.The conditions leading to such behavior, including chain lenght, ionization fraction, ionic strength, molecular structure, and temperature are poorly understood. Though thermodynamic models of this phase separation exist, they offer little descriptive power for the mechanism of complex coacervation, and the internal structure of the coacervate and precipitate phases. Here we use atomic-level and coarse-grained representations of polypeptides to study features of the phase diagram, scaling relations, and microstructure of complex coacervates, comparing results to experimental data and model calculations.

  20. Accessing complexity from genome information

    NASA Astrophysics Data System (ADS)

    Tenreiro Machado, J. A.

    2012-06-01

    This paper studies the information content of the chromosomes of 24 species. In a first phase, a scheme inspired in dynamical system state space representation is developed. For each chromosome the state space dynamical evolution is shed into a two dimensional chart. The plots are then analyzed and characterized in the perspective of fractal dimension. This information is integrated in two measures of the species' complexity addressing its average and variability. The results are in close accordance with phylogenetics pointing quantitative aspects of the species' genomic complexity.

  1. Combination therapeutics in complex diseases.

    PubMed

    He, Bing; Lu, Cheng; Zheng, Guang; He, Xiaojuan; Wang, Maolin; Chen, Gao; Zhang, Ge; Lu, Aiping

    2016-12-01

    The biological redundancies in molecular networks of complex diseases limit the efficacy of many single drug therapies. Combination therapeutics, as a common therapeutic method, involve pharmacological intervention using several drugs that interact with multiple targets in the molecular networks of diseases and may achieve better efficacy and/or less toxicity than monotherapy in practice. The development of combination therapeutics is complicated by several critical issues, including identifying multiple targets, targeting strategies and the drug combination. This review summarizes the current achievements in combination therapeutics, with a particular emphasis on the efforts to develop combination therapeutics for complex diseases.

  2. Synthesis of triamidoamine complexes of niobium

    SciTech Connect

    Freundlich, J.S.; Schrock, R.R.

    1996-12-04

    The authors report the chemical preparation of Nb[N{sub 3}N] complexes. The complexes were characterized by NMR and FT-IR spectroscopy, and X-ray diffraction. The structures of these complexes are presented.

  3. Workspace Program for Complex-Number Arithmetic

    NASA Technical Reports Server (NTRS)

    Patrick, M. C.; Howell, Leonard W., Jr.

    1986-01-01

    COMPLEX is workspace program designed to empower APL with complexnumber capabilities. Complex-variable methods provide analytical tools invaluable for applications in mathematics, science, and engineering. COMPLEX written in APL.

  4. Workspace Program for Complex-Number Arithmetic

    NASA Technical Reports Server (NTRS)

    Patrick, M. C.; Howell, Leonard W., Jr.

    1986-01-01

    COMPLEX is workspace program designed to empower APL with complexnumber capabilities. Complex-variable methods provide analytical tools invaluable for applications in mathematics, science, and engineering. COMPLEX written in APL.

  5. Complex Knowledge Mastery: Some Propositions.

    ERIC Educational Resources Information Center

    Keller, Joyce A.; Schallert, Diane L.

    The proposition that the mastery of complex tasks embodies several components was studied for 236 students in an undergraduate introductory financial accounting course. A new curriculum was developed for the course that included in-depth exposure to the actual financial statements of a company and the understanding of the structural relationships…

  6. Three-Dimensional Complex Variables

    NASA Technical Reports Server (NTRS)

    Martin, E. Dale

    1988-01-01

    Report presents new theory of analytic functions of three-dimensional complex variables. While three-dimensional system subject to more limitations and more difficult to use than the two-dimensional system, useful in analysis of three-dimensional fluid flows, electrostatic potentials, and other phenomena involving harmonic functions.

  7. Ruthenium complexes as antimicrobial agents.

    PubMed

    Li, Fangfei; Collins, J Grant; Keene, F Richard

    2015-04-21

    One of the major advances in medical science has been the development of antimicrobials; however, a consequence of their widespread use has been the emergence of drug-resistant populations of microorganisms. There is clearly a need for the development of new antimicrobials--but more importantly, there is the need for the development of new classes of antimicrobials, rather than drugs based upon analogues of known scaffolds. Due to the success of the platinum anticancer agents, there has been considerable interest in the development of therapeutic agents based upon other transition metals--and in particular ruthenium(II/III) complexes, due to their well known interaction with DNA. There have been many studies of the anticancer properties and cellular localisation of a range of ruthenium complexes in eukaryotic cells over the last decade. However, only very recently has there been significant interest in their antimicrobial properties. This review highlights the types of ruthenium complexes that have exhibited significant antimicrobial activity and discusses the relationship between chemical structure and biological processing--including site(s) of intracellular accumulation--of the ruthenium complexes in both bacterial and eukaryotic cells.

  8. Aromatic triamide-lanthanide complexes

    DOEpatents

    Raymond, Kenneth N; Petoud, Stephane; Xu, Jide

    2013-10-08

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  9. Cognitive Complexity and Interest Crystallization.

    ERIC Educational Resources Information Center

    Winer, Dov; Gati, Itamar

    1986-01-01

    Investigated the relationship between cognitive differentiation and vocational interest crystallization. Results indicated the relationships between measures of cognitive differentiation were generally low, and that interest crystallization was related to between-construct differentiation, but not to the other measures of cognitive complexity.…

  10. Capturing Complexity through Maturity Modelling

    ERIC Educational Resources Information Center

    Underwood, Jean; Dillon, Gayle

    2004-01-01

    The impact of information and communication technologies (ICT) on the process and products of education is difficult to assess for a number of reasons. In brief, education is a complex system of interrelationships, of checks and balances. This context is not a neutral backdrop on which teaching and learning are played out. Rather, it may help, or…

  11. Text Complexity and the CCSS

    ERIC Educational Resources Information Center

    Aspen Institute, 2012

    2012-01-01

    What is meant by text complexity is a measurement of how challenging a particular text is to read. There are a myriad of different ways of explaining what makes text challenging to read, from the sophistication of the vocabulary employed to the length of its sentences to even measurements of how the text as a whole coheres. Research shows that no…

  12. Biomechanics of complex shoulder instability.

    PubMed

    Degen, Ryan M; Giles, Joshua W; Thompson, Stephen R; Litchfield, Robert B; Athwal, George S

    2013-10-01

    Identification and treatment of the osseous lesions associated with complex shoulder instability remains challenging. Further biomechanical testing is required to delineate critical defect values and determine which treatments provide improved glenohumeral joint stability for the various defect sizes, while minimizing the associated complications.

  13. Lignocellulose hydrolysis by multienzyme complexes

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass is the most abundant renewable resource on the planet. Converting this material into a usable fuel is a multi-step process, the rate-limiting step being enzymatic hydrolysis of organic polymers into monomeric sugars. While the substrate can be complex and require a multitud...

  14. Hydrogen storage via polyhydride complexes

    SciTech Connect

    Jensen, C.M.

    1996-10-01

    Polyhydride metal complexes are being developed for application to hydrogen storage. Complexes have been found which catalyze the reversible hydrogenation of unsaturated hydrocarbons. This catalytic reaction could be the basis for a low temperature, hydrogen storage system with a available hydrogen density greater than 7 weight percent. The P-C-P pincer complexes, RhH{sub 2}(C{sub 6}H{sub 3}-2,6-(CH{sub 2}PBu{sup t}{sub 2}){sub 2}) and IrH{sub 2}(C{sub 6}H{sub 3}-2,6-(CH{sub 2}PBu{sup t}{sub 2}){sub 2}) have unprecedented, long term stability at elevated temperatures. The novel iridium complex catalyzes the transfer dehydrogenation of cycloctane to cyclooctene at the rate of 716 turnovers/h which is 2 orders of magnitude greater than that found for previously reported catalytic systems which do not require the sacrificial hydrogenation of a large excess of hydrogen acceptor.

  15. Challenges in complex systems science

    NASA Astrophysics Data System (ADS)

    San Miguel, M.; Johnson, J. H.; Kertesz, J.; Kaski, K.; Díaz-Guilera, A.; MacKay, R. S.; Loreto, V.; Érdi, P.; Helbing, D.

    2012-11-01

    FuturICT foundations are social science, complex systems science, and ICT. The main concerns and challenges in the science of complex systems in the context of FuturICT are laid out in this paper with special emphasis on the Complex Systems route to Social Sciences. This include complex systems having: many heterogeneous interacting parts; multiple scales; complicated transition laws; unexpected or unpredicted emergence; sensitive dependence on initial conditions; path-dependent dynamics; networked hierarchical connectivities; interaction of autonomous agents; self-organisation; non-equilibrium dynamics; combinatorial explosion; adaptivity to changing environments; co-evolving subsystems; ill-defined boundaries; and multilevel dynamics. In this context, science is seen as the process of abstracting the dynamics of systems from data. This presents many challenges including: data gathering by large-scale experiment, participatory sensing and social computation, managing huge distributed dynamic and heterogeneous databases; moving from data to dynamical models, going beyond correlations to cause-effect relationships, understanding the relationship between simple and comprehensive models with appropriate choices of variables, ensemble modeling and data assimilation, modeling systems of systems of systems with many levels between micro and macro; and formulating new approaches to prediction, forecasting, and risk, especially in systems that can reflect on and change their behaviour in response to predictions, and systems whose apparently predictable behaviour is disrupted by apparently unpredictable rare or extreme events. These challenges are part of the FuturICT agenda.

  16. Libraries Serving the CSIR Complex.

    ERIC Educational Resources Information Center

    Rajagopalan, T. S.; Ramaswami, K.

    A survey of the resources and services of the Council of Scientific and Industrial Research (CSIR) libraries was made so that the libraries in the complex could share the benefit of the experiences of each other. The report is based on questionnaire replies received from 31 CSIR Institutions and eight Co-operative Research Associations and relates…

  17. Complex Landscape Terms in Seri

    ERIC Educational Resources Information Center

    O'Meara, Carolyn; Bohnemeyer, Jurgen

    2008-01-01

    The nominal lexicon of Seri is characterized by a prevalence of analytical descriptive terms. We explore the consequences of this typological trait in the landscape domain. The complex landscape terms of Seri classify geographic entities in terms of their material make-up and spatial properties such as shape, orientation, and merological…

  18. Learning To Live with Complexity.

    ERIC Educational Resources Information Center

    Dosa, Marta

    Neither the design of information systems and networks nor the delivery of library services can claim true user centricity without an understanding of the multifaceted psychological environment of users and potential users. The complexity of the political process, social problems, challenges to scientific inquiry, entrepreneurship, and…

  19. Modeling wildfire incident complexity dynamics.

    PubMed

    Thompson, Matthew P

    2013-01-01

    Wildfire management in the United States and elsewhere is challenged by substantial uncertainty regarding the location and timing of fire events, the socioeconomic and ecological consequences of these events, and the costs of suppression. Escalating U.S. Forest Service suppression expenditures is of particular concern at a time of fiscal austerity as swelling fire management budgets lead to decreases for non-fire programs, and as the likelihood of disruptive within-season borrowing potentially increases. Thus there is a strong interest in better understanding factors influencing suppression decisions and in turn their influence on suppression costs. As a step in that direction, this paper presents a probabilistic analysis of geographic and temporal variation in incident management team response to wildfires. The specific focus is incident complexity dynamics through time for fires managed by the U.S. Forest Service. The modeling framework is based on the recognition that large wildfire management entails recurrent decisions across time in response to changing conditions, which can be represented as a stochastic dynamic system. Daily incident complexity dynamics are modeled according to a first-order Markov chain, with containment represented as an absorbing state. A statistically significant difference in complexity dynamics between Forest Service Regions is demonstrated. Incident complexity probability transition matrices and expected times until containment are presented at national and regional levels. Results of this analysis can help improve understanding of geographic variation in incident management and associated cost structures, and can be incorporated into future analyses examining the economic efficiency of wildfire management.

  20. Management of Complex Anal Fistulas

    PubMed Central

    Bubbers, Emily J.; Cologne, Kyle G.

    2016-01-01

    Complex anal fistulas require careful evaluation. Prior to any attempts at definitive repair, the anatomy must be well defined and the sepsis resolved. Several muscle-sparing approaches to anal fistula are appropriate, and are often catered to the patient based on their presentation and previous repairs. Emerging technologies show promise for fistula repair, but lack long-term data. PMID:26929751

  1. Leadership Learning for Complex Organizations

    ERIC Educational Resources Information Center

    Ng, F. S. David

    2015-01-01

    Many school leadership programs are set and delivered in specific modules or workshops in order to achieve a pre-determined set of competencies, knowledge, and skills. In addition, these programs are driven by the faculty member and the prescribed content. As Singapore schools become more complex in the roles and responsibilities to educate the…

  2. Leadership Learning for Complex Organizations

    ERIC Educational Resources Information Center

    Ng, F. S. David

    2015-01-01

    Many school leadership programs are set and delivered in specific modules or workshops in order to achieve a pre-determined set of competencies, knowledge, and skills. In addition, these programs are driven by the faculty member and the prescribed content. As Singapore schools become more complex in the roles and responsibilities to educate the…

  3. TASI Lectures on Complex Structures

    NASA Astrophysics Data System (ADS)

    Denef, Frederik

    2012-11-01

    These lecture notes give an introduction to a number of ideas and methods that have been useful in the study of complex systems ranging from spin glasses to D-branes on Calabi-Yau manifolds. Topics include the replica formalism, Parisi's solution of the Sherrington-Kirkpatrick model, overlap order parameters, supersymmetric quantum mechanics, D-brane landscapes and their black hole duals.

  4. Language Networks as Complex Systems

    ERIC Educational Resources Information Center

    Lee, Max Kueiming; Ou, Sheue-Jen

    2008-01-01

    Starting in the late eighties, with a growing discontent with analytical methods in science and the growing power of computers, researchers began to study complex systems such as living organisms, evolution of genes, biological systems, brain neural networks, epidemics, ecology, economy, social networks, etc. In the early nineties, the research…

  5. The Complexities of Domestic Violence

    ERIC Educational Resources Information Center

    Dutton, Donald G.

    2007-01-01

    Comments on the article by Robert Bornstein, "The complex relationship between dependency and domestic violence: Converging psychological factors and social forces." Although a more focused examination of the psychological factors involved in domestic violence is welcome, there are some factual errors in Bornstein's article that need attention and…

  6. Capturing Complexity through Maturity Modelling

    ERIC Educational Resources Information Center

    Underwood, Jean; Dillon, Gayle

    2004-01-01

    The impact of information and communication technologies (ICT) on the process and products of education is difficult to assess for a number of reasons. In brief, education is a complex system of interrelationships, of checks and balances. This context is not a neutral backdrop on which teaching and learning are played out. Rather, it may help, or…

  7. Complex Landscape Terms in Seri

    ERIC Educational Resources Information Center

    O'Meara, Carolyn; Bohnemeyer, Jurgen

    2008-01-01

    The nominal lexicon of Seri is characterized by a prevalence of analytical descriptive terms. We explore the consequences of this typological trait in the landscape domain. The complex landscape terms of Seri classify geographic entities in terms of their material make-up and spatial properties such as shape, orientation, and merological…

  8. Hybrid estimation of complex systems.

    PubMed

    Hofbaur, Michael W; Williams, Brian C

    2004-10-01

    Modern automated systems evolve both continuously and discretely, and hence require estimation techniques that go well beyond the capability of a typical Kalman Filter. Multiple model (MM) estimation schemes track these system evolutions by applying a bank of filters, one for each discrete system mode. Modern systems, however, are often composed of many interconnected components that exhibit rich behaviors, due to complex, system-wide interactions. Modeling these systems leads to complex stochastic hybrid models that capture the large number of operational and failure modes. This large number of modes makes a typical MM estimation approach infeasible for online estimation. This paper analyzes the shortcomings of MM estimation, and then introduces an alternative hybrid estimation scheme that can efficiently estimate complex systems with large number of modes. It utilizes search techniques from the toolkit of model-based reasoning in order to focus the estimation on the set of most likely modes, without missing symptoms that might be hidden amongst the system noise. In addition, we present a novel approach to hybrid estimation in the presence of unknown behavioral modes. This leads to an overall hybrid estimation scheme for complex systems that robustly copes with unforeseen situations in a degraded, but fail-safe manner.

  9. Biologically Inspired Phosphino Platinum Complexes

    SciTech Connect

    Jain, Avijita; Helm, Monte L.; Linehan, John C.; DuBois, Daniel L.; Shaw, Wendy J.

    2012-08-01

    Platinum complexes containing phosphino amino acid and amino acid ester ligands, built upon the PPhNR’2 platform, have been synthesized and characterized (PPhNR’2= [1,3-diaza]-5-phenyl phosphacyclohexane, R’=glycine or glycine ester). These complexes were characterized by 31P, 13C, 1H, 195Pt NMR spectroscopy and mass spectrometry. The X-ray crystal structure of one of the complexes, [PtCl2(PPhNGlyester 2)2], is also reported. These biologically inspired ligands have potential use in homogeneous catalysis, with special applications in chiral chemistry and water soluble chemistry. These complexes also provide a foundation upon which larger peptides can be attached, to allow the introduction of enzyme-like features onto small molecule catalysts. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  10. Porous Soil as Complex Network

    NASA Astrophysics Data System (ADS)

    Benito, R. M.; Santiago, A.; Cárdenas, J. P.; Tarquis, A. M.; Borondo, F.; Losada, J. C.

    2009-04-01

    We present a complex network model based on a heterogeneous preferential attachment scheme [1,2] to quantify the structure of porous soils [3]. Under this perspective pores are represented by nodes and the space for the flow of fluids between them are represented by links. Pore properties such as position and size are described by fixed states in a metric space, while an affinity function is introduced to bias the attachment probabilities of links according to these properties. We perform an analytical and numerical study of the degree distributions in the soil model and show that under reasonable conditions all the model variants yield a multiscaling behavior in the connectivity degrees, leaving a empirically testable signature of heterogeneity in the topology of pore networks. References [1] A. Santiago and R. M. Benito, "Emergence of multiscaling in heterogeneous complex networks". Int. J. Mod. Phys. C 18, 1591 (2007). [2] A. Santiago and R. M. Benito, "An extended formalism for preferential attachment in heterogeneous complex networks". Europhys. Lett. 82, 58004 (2008). [3] A. Santiago, R. M. Benito, J. P. Cárdenas, J. C. Losada, A. M. Tarquis and F. Borondo, "Multiscaling of porous soils as heterogeneous complex networks". Nonl. Proc. Geophys. 15, 1-10 (2008).

  11. DNA/chitosan electrostatic complex.

    PubMed

    Bravo-Anaya, Lourdes Mónica; Soltero, J F Armando; Rinaudo, Marguerite

    2016-07-01

    Up to now, chitosan and DNA have been investigated for gene delivery due to chitosan advantages. It is recognized that chitosan is a biocompatible and biodegradable non-viral vector that does not produce immunological reactions, contrary to viral vectors. Chitosan has also been used and studied for its ability to protect DNA against nuclease degradation and to transfect DNA into several kinds of cells. In this work, high molecular weight DNA is compacted with chitosan. DNA-chitosan complex stoichiometry, net charge, dimensions, conformation and thermal stability are determined and discussed. The influence of external salt and chitosan molecular weight on the stoichiometry is also discussed. The isoelectric point of the complexes was found to be directly related to the protonation degree of chitosan. It is clearly demonstrated that the net charge of DNA-chitosan complex can be expressed in terms of the ratio [NH3(+)]/[P(-)], showing that the electrostatic interactions between DNA and chitosan are the main phenomena taking place in the solution. Compaction of DNA long chain complexed with low molar mass chitosan gives nanoparticles with an average radius around 150nm. Stable nanoparticles are obtained for a partial neutralization of phosphate ionic sites (i.e.: [NH3(+)]/[P(-)] fraction between 0.35 and 0.80).

  12. Autism in Tuberous Sclerosis Complex.

    ERIC Educational Resources Information Center

    Gutierrez, Griselda C.; Smalley, Susan L.; Tanguay, Peter E.

    1998-01-01

    The frequency and clinical presentation of autism in 28 probands with tuberous sclerosis complex (TSC), an autosomal dominant disorder characterized by benign tissue growths and a high frequency of seizure disorders and mental retardation, was examined. Eight probands met criteria for autism. Implications for understanding the association of…

  13. Let's Piggyback and Forget Complexity.

    ERIC Educational Resources Information Center

    Duane, James E.

    The value of instructional television for universities and public school systems has often been swallowed up in the complexities of producing programs. Television can be better used in the classroom as an instructional resource, taking advantage of already produced programing that is available from sources such as the Public Broadcast Service.…

  14. The Complexities of Domestic Violence

    ERIC Educational Resources Information Center

    Dutton, Donald G.

    2007-01-01

    Comments on the article by Robert Bornstein, "The complex relationship between dependency and domestic violence: Converging psychological factors and social forces." Although a more focused examination of the psychological factors involved in domestic violence is welcome, there are some factual errors in Bornstein's article that need attention and…

  15. Information aspects of actomyosin complex.

    PubMed

    Matsuno, K; Honda, H

    1991-01-01

    Actomyosin complex as a representative case of cell motility exhibits an intricate interplay between the structure it maintains and the function it realizes. The correspondence between structure and function an actomyosin complex displays is a one-to-many type. Mechanochemical couplings underlying the energy transduction associated with the hydrolysis of ATP in the complex render the correspondence between the displacement of the medium and the force acting there a one-to-many type. Such a one-to-many correspondence between displacement and force makes the dynamic development informational in the sense that the prior indefiniteness turns into the posterior definiteness with the elapse of time. This characteristic exhibits sharp contrast to the time-honored one-to-one correspondence between displacement and force that is most common in mechanics, whether classical or quantal, in which no information is generated because of a forcible intrusion of exogenous detection of nonlocal character claiming an instantaneous bird's eye view of everything involved. Information generation is due intrinsically to the process of endogenous detection of local character, and the process has to be local because any physical signal propagates at a finite velocity. Actomyosin complex serves as a material example witnessing that detection of local character certainly generates information and leaves itself nonprogrammable.

  16. Autism in Tuberous Sclerosis Complex.

    ERIC Educational Resources Information Center

    Gutierrez, Griselda C.; Smalley, Susan L.; Tanguay, Peter E.

    1998-01-01

    The frequency and clinical presentation of autism in 28 probands with tuberous sclerosis complex (TSC), an autosomal dominant disorder characterized by benign tissue growths and a high frequency of seizure disorders and mental retardation, was examined. Eight probands met criteria for autism. Implications for understanding the association of…

  17. [Formylation of porphyrin platinum complexes].

    PubMed

    Rumiantseva, V D; Konovalenko, L I; Nagaeva, E A; Mironov, A F

    2005-01-01

    The formylation reaction of platinum complexes of beta-unsubstituted porphyrins was studied. The interaction of deuteroporphyrin IX derivatives with the Vilsmeyer reagent led to the selective formylation of their macrocycles in the beta position. The resulting formyl derivatives of the porphyrins are of interest for fluorescent immunoassay.

  18. Hierarchy Measure for Complex Networks

    PubMed Central

    Mones, Enys; Vicsek, Lilla; Vicsek, Tamás

    2012-01-01

    Nature, technology and society are full of complexity arising from the intricate web of the interactions among the units of the related systems (e.g., proteins, computers, people). Consequently, one of the most successful recent approaches to capturing the fundamental features of the structure and dynamics of complex systems has been the investigation of the networks associated with the above units (nodes) together with their relations (edges). Most complex systems have an inherently hierarchical organization and, correspondingly, the networks behind them also exhibit hierarchical features. Indeed, several papers have been devoted to describing this essential aspect of networks, however, without resulting in a widely accepted, converging concept concerning the quantitative characterization of the level of their hierarchy. Here we develop an approach and propose a quantity (measure) which is simple enough to be widely applicable, reveals a number of universal features of the organization of real-world networks and, as we demonstrate, is capable of capturing the essential features of the structure and the degree of hierarchy in a complex network. The measure we introduce is based on a generalization of the m-reach centrality, which we first extend to directed/partially directed graphs. Then, we define the global reaching centrality (GRC), which is the difference between the maximum and the average value of the generalized reach centralities over the network. We investigate the behavior of the GRC considering both a synthetic model with an adjustable level of hierarchy and real networks. Results for real networks show that our hierarchy measure is related to the controllability of the given system. We also propose a visualization procedure for large complex networks that can be used to obtain an overall qualitative picture about the nature of their hierarchical structure. PMID:22470477

  19. Hierarchy measure for complex networks.

    PubMed

    Mones, Enys; Vicsek, Lilla; Vicsek, Tamás

    2012-01-01

    Nature, technology and society are full of complexity arising from the intricate web of the interactions among the units of the related systems (e.g., proteins, computers, people). Consequently, one of the most successful recent approaches to capturing the fundamental features of the structure and dynamics of complex systems has been the investigation of the networks associated with the above units (nodes) together with their relations (edges). Most complex systems have an inherently hierarchical organization and, correspondingly, the networks behind them also exhibit hierarchical features. Indeed, several papers have been devoted to describing this essential aspect of networks, however, without resulting in a widely accepted, converging concept concerning the quantitative characterization of the level of their hierarchy. Here we develop an approach and propose a quantity (measure) which is simple enough to be widely applicable, reveals a number of universal features of the organization of real-world networks and, as we demonstrate, is capable of capturing the essential features of the structure and the degree of hierarchy in a complex network. The measure we introduce is based on a generalization of the m-reach centrality, which we first extend to directed/partially directed graphs. Then, we define the global reaching centrality (GRC), which is the difference between the maximum and the average value of the generalized reach centralities over the network. We investigate the behavior of the GRC considering both a synthetic model with an adjustable level of hierarchy and real networks. Results for real networks show that our hierarchy measure is related to the controllability of the given system. We also propose a visualization procedure for large complex networks that can be used to obtain an overall qualitative picture about the nature of their hierarchical structure.

  20. Neural Mechanisms Underlying Breathing Complexity

    PubMed Central

    Hess, Agathe; Yu, Lianchun; Klein, Isabelle; De Mazancourt, Marine; Jebrak, Gilles; Mal, Hervé; Brugière, Olivier; Fournier, Michel; Courbage, Maurice; Dauriat, Gaelle; Schouman-Clayes, Elisabeth; Clerici, Christine; Mangin, Laurence

    2013-01-01

    Breathing is maintained and controlled by a network of automatic neurons in the brainstem that generate respiratory rhythm and receive regulatory inputs. Breathing complexity therefore arises from respiratory central pattern generators modulated by peripheral and supra-spinal inputs. Very little is known on the brainstem neural substrates underlying breathing complexity in humans. We used both experimental and theoretical approaches to decipher these mechanisms in healthy humans and patients with chronic obstructive pulmonary disease (COPD). COPD is the most frequent chronic lung disease in the general population mainly due to tobacco smoke. In patients, airflow obstruction associated with hyperinflation and respiratory muscles weakness are key factors contributing to load-capacity imbalance and hence increased respiratory drive. Unexpectedly, we found that the patients breathed with a higher level of complexity during inspiration and expiration than controls. Using functional magnetic resonance imaging (fMRI), we scanned the brain of the participants to analyze the activity of two small regions involved in respiratory rhythmogenesis, the rostral ventro-lateral (VL) medulla (pre-Bötzinger complex) and the caudal VL pons (parafacial group). fMRI revealed in controls higher activity of the VL medulla suggesting active inspiration, while in patients higher activity of the VL pons suggesting active expiration. COPD patients reactivate the parafacial to sustain ventilation. These findings may be involved in the onset of respiratory failure when the neural network becomes overwhelmed by respiratory overload We show that central neural activity correlates with airflow complexity in healthy subjects and COPD patients, at rest and during inspiratory loading. We finally used a theoretical approach of respiratory rhythmogenesis that reproduces the kernel activity of neurons involved in the automatic breathing. The model reveals how a chaotic activity in neurons can

  1. Complex DNA structures and structures of DNA complexes

    SciTech Connect

    Chazin, W.J.; Carlstroem, G.; Shiow-Meei Chen; Miick, S.; Gomez-Paloma, L.; Smith, J.; Rydzewski, J.

    1994-12-01

    Complex DNA structures (for example, triplexes, quadruplexes, junctions) and DNA-ligand complexes are more difficult to study by NMR than standard DNA duplexes are because they have high molecular weights, show nonstandard or distorted local conformations, and exhibit large resonance linewidths and severe {sup 1}H spectral overlap. These systems also tend to have limited solubility and may require specialized solution conditions to maintain favorable spectral characteristics, which adds to the spectroscopic difficulties. Furthermore, with more atoms in the system, both assignment and structure calculation become more challenging. In this article, we focus on demonstrating the current status of NMR studies of such systems and the limitations to further progress; we also indicate in what ways isotopic enrichment can be useful.

  2. I. Redox chemistry of bimetallic fulvalene complexes II. Oligocyclopentadienyl complexes

    SciTech Connect

    Brown, David Stephen

    1993-11-01

    The electrochemistry of the heterobimetallic complexes (fulvalene)WFe(CO)5 (30) and (fulvalene)WRu(CO)5 (31) has been investigated. Compound 30 is reduced in two one-electron processes, and this behavior was exploited synthetically to prepare a tetranuclear dimer by selective metal reduction. Complex 31 displayed a distinction between the metals upon reoxidation of the dianion, allowing the formation of a dimer by selective metal anion oxidation. The redox behavior of 30 led to an investigation of the use of electrocatalysis to effect metal-specific ligand substitution. It was found that reduction of 30 with a catalytic amount of CpFe(C6Me6) (97) in the presence of excess P(OMe)3 or PMe5 led to the formation of the zwitterions (fulvalene)[W(CO)3-][Fe(CO)PR3+] (107, R = P(OMe)3; 108, R = PMe3). Compound 31 also displayed unique behavior with different reducing agents, as the monosubstituted zwitterion (fulvalene)[W(CO)3-][Ru(CO)2(PMe3+] was obtained when 97 was used while the disubstituted complex (fulvalene) [W(CO)3-] [Ru(CO)(PMe3)2+] was produced when Cp*Fe(C6Me6) was the catalyst. Potential synthetic routes to quatercyclopentadienyl complexes were also explored. Various attempts to couple heterobimetallic fulvalene compounds proved to be unsuccessful. 138 refs.

  3. Complex quantum network model of energy transfer in photosynthetic complexes.

    PubMed

    Ai, Bao-Quan; Zhu, Shi-Liang

    2012-12-01

    The quantum network model with real variables is usually used to describe the excitation energy transfer (EET) in the Fenna-Matthews-Olson (FMO) complexes. In this paper we add the quantum phase factors to the hopping terms and find that the quantum phase factors play an important role in the EET. The quantum phase factors allow us to consider the space structure of the pigments. It is found that phase coherence within the complexes would allow quantum interference to affect the dynamics of the EET. There exist some optimal phase regions where the transfer efficiency takes its maxima, which indicates that when the pigments are optimally spaced, the exciton can pass through the FMO with perfect efficiency. Moreover, the optimal phase regions almost do not change with the environments. In addition, we find that the phase factors are useful in the EET just in the case of multiple pathways. Therefore, we demonstrate that the quantum phases may bring the other two factors, the optimal space of the pigments and multiple pathways, together to contribute the EET in photosynthetic complexes with perfect efficiency.

  4. Is a "Complex" Task Really Complex? Validating the Assumption of Cognitive Task Complexity

    ERIC Educational Resources Information Center

    Sasayama, Shoko

    2016-01-01

    In research on task-based learning and teaching, it has traditionally been assumed that differing degrees of cognitive task complexity can be inferred through task design and/or observations of differing qualities in linguistic production elicited by second language (L2) communication tasks. Without validating this assumption, however, it is…

  5. Is a "Complex" Task Really Complex? Validating the Assumption of Cognitive Task Complexity

    ERIC Educational Resources Information Center

    Sasayama, Shoko

    2016-01-01

    In research on task-based learning and teaching, it has traditionally been assumed that differing degrees of cognitive task complexity can be inferred through task design and/or observations of differing qualities in linguistic production elicited by second language (L2) communication tasks. Without validating this assumption, however, it is…

  6. Physical approach to complex systems

    NASA Astrophysics Data System (ADS)

    Kwapień, Jarosław; Drożdż, Stanisław

    2012-06-01

    Typically, complex systems are natural or social systems which consist of a large number of nonlinearly interacting elements. These systems are open, they interchange information or mass with environment and constantly modify their internal structure and patterns of activity in the process of self-organization. As a result, they are flexible and easily adapt to variable external conditions. However, the most striking property of such systems is the existence of emergent phenomena which cannot be simply derived or predicted solely from the knowledge of the systems’ structure and the interactions among their individual elements. This property points to the holistic approaches which require giving parallel descriptions of the same system on different levels of its organization. There is strong evidence-consolidated also in the present review-that different, even apparently disparate complex systems can have astonishingly similar characteristics both in their structure and in their behaviour. One can thus expect the existence of some common, universal laws that govern their properties. Physics methodology proves helpful in addressing many of the related issues. In this review, we advocate some of the computational methods which in our opinion are especially fruitful in extracting information on selected-but at the same time most representative-complex systems like human brain, financial markets and natural language, from the time series representing the observables associated with these systems. The properties we focus on comprise the collective effects and their coexistence with noise, long-range interactions, the interplay between determinism and flexibility in evolution, scale invariance, criticality, multifractality and hierarchical structure. The methods described either originate from “hard” physics-like the random matrix theory-and then were transmitted to other fields of science via the field of complex systems research, or they originated elsewhere but

  7. Determination of Complex Microcalorimeter Parameters with Impedance Measurements

    NASA Technical Reports Server (NTRS)

    Saab, T.; Bandler, S. R.; Chervenak, J.; Figueroa-Feliciano, E.; Finkbeiner, F.; Iyomoto, N.; Kelley, R.; Kilbourne, C. A.; Lindeman, M. A.; Porter, F. S.; hide

    2005-01-01

    The proper understanding and modeling of a microcalorimeter s response requires the accurate knowledge of a handful of parameters, such as C, G, alpha, . . . . While a few of these, such 8s the normal state resistance and the total thermal conductance to the heat bath (G) are directly determined from the DC IV characteristics, some others, notoriously the heat capacity (C) and alpha, appear in degenerate combinations in most measurable quantities. The case of a complex microcalorimeter, i.e. one in which the absorber s heat capacity is connected by a finite thermal impedance to the sensor, and subsequently by another thermal impedance to the heat bath, results in an added ambiguity in the determination of the individual C's and G's. In general, the dependence of the microcalorimeter s complex impedance on these parameters varies with frequency. This variation allows us to determine the individual parameters by fitting the prediction of the microcalorimeter model to the impedance data. We describe in this paper our efforts at characterizing the Goddard X-ray microcalorimeters. Using the parameters determined with this method we them compare the pulse shape and noise spectra predicted by the microcalorimeter model to data taken with the same devices.

  8. Determination of Complex Microcalorimeter Parameters with Impedance Measurements

    NASA Technical Reports Server (NTRS)

    Saab, T.; Bandler, S. R.; Chervenak, J.; Figueroa-Feliciano, E.; Finkbeiner, F.; Iyomoto, N.; Kelley, R.; Kilbourne, C. A.; Lindeman, M. A.; Porter, F. S.; Sadleir, J.

    2005-01-01

    The proper understanding and modeling of a microcalorimeter s response requires the accurate knowledge of a handful of parameters, such as C, G, alpha, . . . . While a few of these, such 8s the normal state resistance and the total thermal conductance to the heat bath (G) are directly determined from the DC IV characteristics, some others, notoriously the heat capacity (C) and alpha, appear in degenerate combinations in most measurable quantities. The case of a complex microcalorimeter, i.e. one in which the absorber s heat capacity is connected by a finite thermal impedance to the sensor, and subsequently by another thermal impedance to the heat bath, results in an added ambiguity in the determination of the individual C's and G's. In general, the dependence of the microcalorimeter s complex impedance on these parameters varies with frequency. This variation allows us to determine the individual parameters by fitting the prediction of the microcalorimeter model to the impedance data. We describe in this paper our efforts at characterizing the Goddard X-ray microcalorimeters. Using the parameters determined with this method we them compare the pulse shape and noise spectra predicted by the microcalorimeter model to data taken with the same devices.

  9. Disorder in Complex Human System

    NASA Astrophysics Data System (ADS)

    Akdeniz, K. Gediz

    2011-11-01

    Since the world of human and whose life becomes more and more complex every day because of the digital technology and under the storm of knowledge (media, internet, governmental and non-governmental organizations, etc...) the simulation is rapidly growing in the social systems and in human behaviors. The formation of the body and mutual interactions are left to digital technological, communication mechanisms and coding the techno genetics of the body. Deconstruction begins everywhere. The linear simulation mechanism with modern realities are replaced by the disorder simulation of human behaviors with awareness realities. In this paper I would like to introduce simulation theory of "Disorder Sensitive Human Behaviors". I recently proposed this theory to critique the role of disorder human behaviors in social systems. In this theory the principle of realty is the chaotic awareness of the complexity of human systems inside of principle of modern thinking in Baudrillard's simulation theory. Proper examples will be also considered to investigate the theory.

  10. Imaging an Adapted Dentoalveolar Complex

    PubMed Central

    Herber, Ralf-Peter; Fong, Justine; Lucas, Seth A.; Ho, Sunita P.

    2012-01-01

    Adaptation of a rat dentoalveolar complex was illustrated using various imaging modalities. Micro-X-ray computed tomography for 3D modeling, combined with complementary techniques, including image processing, scanning electron microscopy, fluorochrome labeling, conventional histology (H&E, TRAP), and immunohistochemistry (RANKL, OPN) elucidated the dynamic nature of bone, the periodontal ligament-space, and cementum in the rat periodontium. Tomography and electron microscopy illustrated structural adaptation of calcified tissues at a higher resolution. Ongoing biomineralization was analyzed using fluorochrome labeling, and by evaluating attenuation profiles using virtual sections from 3D tomographies. Osteoclastic distribution as a function of anatomical location was illustrated by combining histology, immunohistochemistry, and tomography. While tomography and SEM provided past resorption-related events, future adaptive changes were deduced by identifying matrix biomolecules using immunohistochemistry. Thus, a dynamic picture of the dentoalveolar complex in rats was illustrated. PMID:22567314

  11. Note on subregion holographic complexity

    NASA Astrophysics Data System (ADS)

    Roy, Pratim; Sarkar, Tapobrata

    2017-07-01

    The volume inside a Ryu-Takayanagi surface has been conjectured to be related to the complexity of subregions of the boundary field theory. Here, we study the behavior of this volume analytically, when the entangling surface has a strip geometry. We perform systematic expansions in the low- and high-temperature regimes for AdS-Schwarzschild and RN-AdS black holes. In the latter regime, we point out spurious divergences that might occur due to the limitations of a near horizon expansion. A similar analysis is performed for extremal black holes and, at large charge, we find that there might be some new features of the volume as compared to the area. Finally, we numerically study a four-dimensional RN-AdS black hole in global AdS, the entangling surface being a sphere. We find that the holographic complexity captures essentially the same information as the entanglement entropy, as far as phase transitions are concerned.

  12. Methoxyethanol, Ethoxyethanol, and Spectral Complexity

    NASA Astrophysics Data System (ADS)

    Westerfield, J. H.; Riffe, Erika; Phillips, Maria; Johnson, Erika; Shipman, Steven

    2017-06-01

    Over the last few years, we have been working to improve the AUTOFIT programpand extend it to work on more complex spectra, especially spectra collected near room temperature. In this talk, we will discuss the problem of spectral complexity and the challenges it poses for moving to increasingly complicated systems. This will be highlighted by the cases of methoxyethanol, in which AUTOFIT was able to easily extract contributions from the ground state and four vibrationally excited states, and ethoxyethanol, in which AUTOFIT had difficulty identifying more than the ground vibrational state without the assistance of additional double resonance measurements. Seifert, N.A., Finneran, I.A., Perez, C., Zaleski, D.P., Neill, J.L., Steber, A.L., Suenram, R.D., Lesarri, A., Shipman, S.T., Pate, B.H., J. Mol. Spec. 312, 13-21 (2015)

  13. Computational complexity of Boolean functions

    NASA Astrophysics Data System (ADS)

    Korshunov, Aleksei D.

    2012-02-01

    Boolean functions are among the fundamental objects of discrete mathematics, especially in those of its subdisciplines which fall under mathematical logic and mathematical cybernetics. The language of Boolean functions is convenient for describing the operation of many discrete systems such as contact networks, Boolean circuits, branching programs, and some others. An important parameter of discrete systems of this kind is their complexity. This characteristic has been actively investigated starting from Shannon's works. There is a large body of scientific literature presenting many fundamental results. The purpose of this survey is to give an account of the main results over the last sixty years related to the complexity of computation (realization) of Boolean functions by contact networks, Boolean circuits, and Boolean circuits without branching. Bibliography: 165 titles.

  14. Griffiths phases on complex networks.

    PubMed

    Muñoz, Miguel A; Juhász, Róbert; Castellano, Claudio; Odor, Géza

    2010-09-17

    Quenched disorder is known to play a relevant role in dynamical processes and phase transitions. Its effects on the dynamics of complex networks have hardly been studied. Aimed at filling this gap, we analyze the contact process, i.e., the simplest propagation model, with quenched disorder on complex networks. We find Griffiths phases and other rare-region effects, leading rather generically to anomalously slow (algebraic, logarithmic, …) relaxation, on Erdos-Rényi networks. Similar effects are predicted to exist for other topologies with a finite percolation threshold. More surprisingly, we find that Griffiths phases can also emerge in the absence of quenched disorder, as a consequence of topological heterogeneity in networks with finite topological dimension. These results have a broad spectrum of implications for propagation phenomena and other dynamical processes on networks.

  15. Epistasis correlates to genomic complexity

    PubMed Central

    Sanjuán, Rafael; Elena, Santiago F.

    2006-01-01

    Whether systematic genetic interactions (epistasis) occur at the genomic scale remains a challenging topic in evolutionary biology. Epistasis should make a significant contribution to variation in complex traits and influence the evolution of genetic systems as sex, diploidy, dominance, or the contamination of genomes with deleterious mutations. We have collected data from widely different organisms and quantified epistasis in a common, per-generation scale. Simpler genomes, such as those of RNA viruses, display antagonistic epistasis (mutations have smaller effects together than expected); bacterial microorganisms do not apparently deviate from independent effects, whereas in multicellular eukaryotes, a transition toward synergistic epistasis occurs (mutations have larger effects together than expected). We propose that antagonistic epistasis might be a property of compact genomes with few nonpleiotropic biological functions, whereas in complex genomes, synergism might emerge from mutational robustness. PMID:16983079

  16. Computational complexity in electronic structure.

    PubMed

    Whitfield, James Daniel; Love, Peter John; Aspuru-Guzik, Alán

    2013-01-14

    In quantum chemistry, the price paid by all known efficient model chemistries is either the truncation of the Hilbert space or uncontrolled approximations. Theoretical computer science suggests that these restrictions are not mere shortcomings of the algorithm designers and programmers but could stem from the inherent difficulty of simulating quantum systems. Extensions of computer science and information processing exploiting quantum mechanics has led to new ways of understanding the ultimate limitations of computational power. Interestingly, this perspective helps us understand widely used model chemistries in a new light. In this article, the fundamentals of computational complexity will be reviewed and motivated from the vantage point of chemistry. Then recent results from the computational complexity literature regarding common model chemistries including Hartree-Fock and density functional theory are discussed.

  17. Decameric uracil complexes around Li+.

    PubMed

    Zins, Emilie-Laure; Pepe, Claude; Schröder, Detlef

    2010-07-01

    Electrospray ionization (ESI) in combination with mass spectrometry (MS) experiments were carried out to study decameric uracil complexes cationized with Li(+) ion. A previous study has shown that, under specific experimental conditions, a particularly intense peak of the decamer U(10)Li(+) is formed, which was referred to as an indication for so-called 'magic number' cluster. In order to gain more insight on the structure of this decameric complex, here, we report experimental studies concerning the kinetics of the fragmentation. In accordance with the new experimental data, structural models were constructed and fully optimized using ab initio and density functional theory quantum chemistry calculations. The theoretical study allowed us to propose a stable gas-phase structure which is compatible with all experimental findings. 2010 John Wiley & Sons, Ltd.

  18. Chaos and complexity by design

    NASA Astrophysics Data System (ADS)

    Roberts, Daniel A.; Yoshida, Beni

    2017-04-01

    We study the relationship between quantum chaos and pseudorandomness by developing probes of unitary design. A natural probe of randomness is the "frame poten-tial," which is minimized by unitary k-designs and measures the 2-norm distance between the Haar random unitary ensemble and another ensemble. A natural probe of quantum chaos is out-of-time-order (OTO) four-point correlation functions. We show that the norm squared of a generalization of out-of-time-order 2 k-point correlators is proportional to the kth frame potential, providing a quantitative connection between chaos and pseudorandomness. Additionally, we prove that these 2 k-point correlators for Pauli operators completely determine the k-fold channel of an ensemble of unitary operators. Finally, we use a counting argument to obtain a lower bound on the quantum circuit complexity in terms of the frame potential. This provides a direct link between chaos, complexity, and randomness.

  19. Reactive immunization on complex networks

    NASA Astrophysics Data System (ADS)

    Alfinito, Eleonora; Beccaria, Matteo; Fachechi, Alberto; Macorini, Guido

    2017-01-01

    Epidemic spreading on complex networks depends on the topological structure as well as on the dynamical properties of the infection itself. Generally speaking, highly connected individuals play the role of hubs and are crucial to channel information across the network. On the other hand, static topological quantities measuring the connectivity structure are independent of the dynamical mechanisms of the infection. A natural question is therefore how to improve the topological analysis by some kind of dynamical information that may be extracted from the ongoing infection itself. In this spirit, we propose a novel vaccination scheme that exploits information from the details of the infection pattern at the moment when the vaccination strategy is applied. Numerical simulations of the infection process show that the proposed immunization strategy is effective and robust on a wide class of complex networks.

  20. Leptogenesis in Complex Hybrid Inflation

    SciTech Connect

    Martinez-Prieto, Carlos

    2008-12-04

    We study the transference of an initial leptonic charge contained in a complex scalar field (waterfall field) at the end of the inflation to the leptons of the standard model and then convert this leptonic charge in baryonic charge by sphaleron process. The proposal is that this is done trough the decay of the complex scalar field particles into the the right-handed neutrino which in turn decays into the left-handed lepton doublet and the Higgs field of the standard model. It must be analyzed in what environment the transference is done. We propose that the inflaton (the dominant energy density of the universe) decay into ultrarelativistic fermions before the waterfall field particles decay in the right handed-neutrino, leaving a thermalized bath where the transference of the leptonic asymmetry can be achieved.