WorldWideScience

Sample records for non-mammalian model organisms

  1. Mottled Mice and Non-Mammalian Models of Menkes Disease.

    Science.gov (United States)

    Lenartowicz, Małgorzata; Krzeptowski, Wojciech; Lipiński, Paweł; Grzmil, Paweł; Starzyński, Rafał; Pierzchała, Olga; Møller, Lisbeth Birk

    2015-01-01

    Menkes disease is a multi-systemic copper metabolism disorder caused by mutations in the X-linked ATP7A gene and characterized by progressive neurodegeneration and severe connective tissue defects. The ATP7A protein is a copper (Cu)-transporting ATPase expressed in all tissues and plays a critical role in the maintenance of copper homeostasis in cells of the whole body. ATP7A participates in copper absorption in the small intestine and in copper transport to the central nervous system (CNS) across the blood-brain-barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). Cu is essential for synaptogenesis and axonal development. In cells, ATP7A participates in the incorporation of copper into Cu-dependent enzymes during the course of its maturation in the secretory pathway. There is a high degree of homology (>80%) between the human ATP7A and murine Atp7a genes. Mice with mutations in the Atp7a gene, called mottled mutants, are well-established and excellent models of Menkes disease. Mottled mutants closely recapitulate the Menkes phenotype and are invaluable for studying Cu-metabolism. They provide useful models for exploring and testing new forms of therapy in Menkes disease. Recently, non-mammalian models of Menkes disease, Drosophila melanogaster and Danio rerio mutants were used in experiments which would be technically difficult to carry out in mammals.

  2. Mottled mice and non-mammalian models of Menkes disease

    Directory of Open Access Journals (Sweden)

    malgorzata elenartowicz

    2015-12-01

    Full Text Available Menkes disease is a multi-systemic copper metabolism disorder caused by mutations in the X-linked ATP7A gene and characterised by progressive neurodegeneration and severe connective tissue defects. The ATP7A protein is a Copper (Cu-transporting ATPase expressed in all tissues and plays a critical role in the maintenance of copper homeostasis in cells of the whole body. ATP7A participates in copper absorption in the small intestine and in copper transport to the CNS across the blood-brain-barrier and blood–cerebrospinal fluid- barrier. Cu is essential for synaptogenesis and axonal development. In cells, ATP7A participates in the incorporation of copper into Cu-dependent enzymes during the course of its maturation in the secretory pathway. There is a high degree of homology (>80% between the human ATP7A and murine Atp7a genes. Mice with mutations in the Atp7a gene, called mottled mutants, are well-established and excellent models of Menkes disease. Mottled mutants closely recapitulate the Menkes phenotype and are invaluable for studying Cu-metabolism. They provide useful models for exploring and testing new forms of therapy in Menkes disease. Recently, non-mammalian models of Menkes disease, Drosophila melanogaster and Danio rerio mutants were used in experiments which would be technically difficult to carry out in mammals.

  3. Non-Mammalian Vertebrates: Distinct Models to Assess the Role of Ion Gradients in Energy Expenditure.

    Science.gov (United States)

    Geisler, Caroline E; Kentch, Kyle P; Renquist, Benjamin J

    2017-01-01

    Animals store metabolic energy as electrochemical gradients. At least 50% of mammalian energy is expended to maintain electrochemical gradients across the inner mitochondrial membrane (H(+)), the sarcoplasmic reticulum (Ca(++)), and the plasma membrane (Na(+)/K(+)). The potential energy of these gradients can be used to perform work (e.g., transport molecules, stimulate contraction, and release hormones) or can be released as heat. Because ectothermic species adapt their body temperature to the environment, they are not constrained by energetic demands that are required to maintain a constant body temperature. In fact, ectothermic species expend seven to eight times less energy than similarly sized homeotherms. Accordingly, ectotherms adopt low metabolic rates to survive cold, hypoxia, and extreme bouts of fasting that would result in energy wasting, lactic acidosis and apoptosis, or starvation in homeotherms, respectively. Ectotherms have also evolved unique applications of ion gradients to allow for localized endothermy. Endothermic avian species, which lack brown adipose tissue, have been integral in assessing the role of H(+) and Ca(++) cycling in skeletal muscle thermogenesis. Accordingly, the diversity of non-mammalian vertebrate species allows them to serve as unique models to better understand the role of ion gradients in heat production, metabolic flux, and adaptation to stressors, including obesity, starvation, cold, and hypoxia.

  4. Non-mammalian models reveal the role of alternative ligands for thyroid hormone receptors.

    Science.gov (United States)

    Orozco, Aurea; Lazcano, Iván; Hernández-Puga, Gabriela; Olvera, Aurora

    2017-03-04

    Thyroid hormones, or THs, are well-known regulators of a wide range of biological processes that occur throughout the lifespan of all vertebrates. THs act through genomic mechanisms mediated by thyroid hormone receptors (TRs). The main product of the thyroid gland is thyroxine or T4, which can be further transformed by different biochemical pathways to produce at least 15 active or inactive molecules. T3, a product of T4 outer-ring deiodination, has been recognized as the main bioactive TH. However, growing evidence has shown that other TH derivatives are able to bind to, and/or activate TRs, to induce thyromimetic effects. The compiled data in this review points to at least two of these TR alternative ligands: TRIAC and T2. Taking this into account, non-mammalian models have proven to be advantageous to explore new TH derivatives with potential novel actions, prompting a re-evaluation of the role and mechanism of action of TR alternative ligands that were previously believed to be inactive. The functional implications of these ligands across different vertebrates may require us to reconsider current established notions of thyroid physiology. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Japanese medaka: a non-mammalian vertebrate model for studying sex and age-related bone metabolism in vivo.

    Directory of Open Access Journals (Sweden)

    Admane H Shanthanagouda

    Full Text Available BACKGROUND: In human, a reduction in estrogen has been proposed as one of the key contributing factors for postmenopausal osteoporosis. Rodents are conventional models for studying postmenopausal osteoporosis, but the major limitation is that ovariectomy is needed to mimic the estrogen decline after menopause. Interestingly, in medaka fish (Oryzias latipes, we observed a natural drop in plasma estrogen profile in females during aging and abnormal spinal curvature was apparent in old fish, which are similar to postmenopausal women. It is hypothesized that estrogen associated disorders in bone metabolism might be predicted and prevented by estrogen supplement in aging O. latipes, which could be corresponding to postmenopausal osteoporosis in women. PRINCIPAL FINDINGS: In O. latipes, plasma estrogen was peaked at 8 months old and significantly declined after 10, 11 and 22 months in females. Spinal bone mineral density (BMD and micro-architecture by microCT measurement progressively decreased and deteriorated from 8 to 10, 12 and 14 months old, which was more apparent in females than the male counterparts. After 10 months old, O. latipes were supplemented with 17α-ethinylestradiol (EE2, a potent estrogen mimic at 6 and 60 ng/mg fish weight/day for 4 weeks, both reduction in spinal BMD and deterioration in bone micro-architecture were significantly prevented. The estrogenic effect of EE2 in O. latipes was confirmed by significant up-regulation of four key estrogen responsive genes in the liver. In general, bone histomorphometric analyses indicated significantly lowered osteoblasts and osteoclasts numbers and surfaces on vertebrae of EE2-fed medaka. SIGNIFICANCE: We demonstrate osteoporosis development associated with natural drop in estrogen level during aging in female medaka, which could be attenuated by estrogen treatment. This small size fish is a unique alternative non-mammalian vertebrate model for studying estrogen-related molecular

  6. Mottled Mice and Non-Mammalian Models of Menkes Disease

    OpenAIRE

    malgorzata elenartowicz; Wojciech eKrzeptowski; Paweł eLipinski; Pawel eGrzmil; Rafał eStarzyński; Olga ePierzchała; Lisbeth Birk eMøller

    2015-01-01

    Menkes disease is a multi-systemic copper metabolism disorder caused by mutations in the X-linked ATP7A gene and characterized by progressive neurodegeneration and severe connective tissue defects. The ATP7A protein is a copper (Cu)-transporting ATPase expressed in all tissues and plays a critical role in the maintenance of copper homeostasis in cells of the whole body. ATP7A participates in copper absorption in the small intestine and in copper transport to the central nervous system (CNS) a...

  7. Mottled Mice and Non-Mammalian Models of Menkes Disease

    DEFF Research Database (Denmark)

    Lenartowicz, Małgorzata; Krzeptowski, Wojciech; Lipiński, Paweł

    2015-01-01

    role in the maintenance of copper homeostasis in cells of the whole body. ATP7A participates in copper absorption in the small intestine and in copper transport to the central nervous system (CNS) across the blood-brain-barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). Cu is essential...... for synaptogenesis and axonal development. In cells, ATP7A participates in the incorporation of copper into Cu-dependent enzymes during the course of its maturation in the secretory pathway. There is a high degree of homology (>80%) between the human ATP7A and murine Atp7a genes. Mice with mutations in the Atp7a......Menkes disease is a multi-systemic copper metabolism disorder caused by mutations in the X-linked ATP7A gene and characterized by progressive neurodegeneration and severe connective tissue defects. The ATP7A protein is a copper (Cu)-transporting ATPase expressed in all tissues and plays a critical...

  8. Plasticizer endocrine disruption: Highlighting developmental and reproductive effects in mammals and non-mammalian aquatic species.

    Science.gov (United States)

    Mathieu-Denoncourt, Justine; Wallace, Sarah J; de Solla, Shane R; Langlois, Valerie S

    2015-08-01

    Due to their versatility, robustness, and low production costs, plastics are used in a wide variety of applications. Plasticizers are mixed with polymers to increase flexibility of plastics. However, plasticizers are not covalently bound to plastics, and thus leach from products into the environment. Several studies have reported that two common plasticizers, bisphenol A (BPA) and phthalates, induce adverse health effects in vertebrates; however few studies have addressed their toxicity to non-mammalian species. The aim of this review is to compare the effects of plasticizers in animals, with a focus on aquatic species. In summary, we identified three main chains of events that occur in animals exposed to BPA and phthalates. Firstly, plasticizers affect development by altering both the thyroid hormone and growth hormone axes. Secondly, these chemicals interfere with reproduction by decreasing cholesterol transport through the mitochondrial membrane, leading to reduced steroidogenesis. Lastly, exposure to plasticizers leads to the activation of peroxisome proliferator-activated receptors, the increase of fatty acid oxidation, and the reduction in the ability to cope with the augmented oxidative stress leading to reproductive organ malformations, reproductive defects, and decreased fertility. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Evolutionary patterns of RNA-based duplication in non-mammalian chordates.

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    Ming Chen

    Full Text Available The role of RNA-based duplication, or retroposition, in the evolution of new gene functions in mammals, plants, and Drosophila has been widely reported. However, little is known about RNA-based duplication in non-mammalian chordates. In this study, we screened ten non-mammalian chordate genomes for retrocopies and investigated their evolutionary patterns. We identified numerous retrocopies in these species. Examination of the age distribution of these retrocopies revealed no burst of young retrocopies in ancient chordate species. Upon comparing these non-mammalian chordate species to the mammalian species, we observed that a larger fraction of the non-mammalian retrocopies was under strong evolutionary constraints than mammalian retrocopies are, as evidenced by signals of purifying selection and expression profiles. For the Western clawed frog, Medaka, and Sea squirt, many retrogenes have evolved gonad and brain expression patterns, similar to what was observed in human. Testing of retrogene movement in the Medaka genome, where the nascent sex chrosomes have been well assembled, did not reveal any significant gene movement. Taken together, our analyses demonstrate that RNA-based duplication generates many functional genes and can make a significant contribution to the evolution of non-mammalian genomes.

  10. Regulatory peptides and control of food intake in non-mammalian vertebrates.

    Science.gov (United States)

    Jensen, J

    2001-03-01

    The current view of the control of food intake involves a central feeding system in the hypothalamus receiving input from peripheral systems. The presence of food in the gut stimulates the release of several regulatory peptides that control gut motility and secretion. Some of these peptides also act as feedback satiety signals, responsible for termination of a meal. Among the regulatory peptides suggested as peripheral satiety signals are cholecystokinin and gastrin releasing peptide. A more long-term peripheral regulation of food intake has also been postulated and leptin has been suggested as a regulator of food intake. Several regulatory peptides mediate orexigenic or anorexigenic effects in the central feeding system. Neuropeptide Y and galanin both act centrally and stimulate the intake of food, while corticotropin releasing factor reduces food intake. At present, most information about the regulation of food intake is gained from mammalian studies and these findings are used as a base for a discussion on the current knowledge of how regulatory peptides control appetite in non-mammalian vertebrates.

  11. Myriocin significantly increases the mortality of a non-mammalian model host during Candida pathogenesis.

    Directory of Open Access Journals (Sweden)

    Nadja Rodrigues de Melo

    Full Text Available Candida albicans is a major human pathogen whose treatment is challenging due to antifungal drug toxicity, drug resistance and paucity of antifungal agents available. Myrocin (MYR inhibits sphingosine synthesis, a precursor of sphingolipids, an important cell membrane and signaling molecule component. MYR also has dual immune suppressive and antifungal properties, potentially modulating mammalian immunity and simultaneously reducing fungal infection risk. Wax moth (Galleria mellonella larvae, alternatives to mice, were used to establish if MYR suppressed insect immunity and increased survival of C. albicans-infected insects. MYR effects were studied in vivo and in vitro, and compared alone and combined with those of approved antifungal drugs, fluconazole (FLC and amphotericin B (AMPH. Insect immune defenses failed to inhibit C. albicans with high mortalities. In insects pretreated with the drug followed by C. albicans inoculation, MYR+C. albicans significantly increased mortality to 93% from 67% with C. albicans alone 48 h post-infection whilst AMPH+C. albicans and FLC+C. albicans only showed 26% and 0% mortalities, respectively. MYR combinations with other antifungal drugs in vivo also enhanced larval mortalities, contrasting the synergistic antifungal effect of the MYR+AMPH combination in vitro. MYR treatment influenced immunity and stress management gene expression during C. albicans pathogenesis, modulating transcripts putatively associated with signal transduction/regulation of cytokines, I-kappaB kinase/NF-kappaB cascade, G-protein coupled receptor and inflammation. In contrast, all stress management gene expression was down-regulated in FLC and AMPH pretreated C. albicans-infected insects. Results are discussed with their implications for clinical use of MYR to treat sphingolipid-associated disorders.

  12. Teaching biology with model organisms

    Science.gov (United States)

    Keeley, Dolores A.

    The purpose of this study is to identify and use model organisms that represent each of the kingdoms biologists use to classify organisms, while experiencing the process of science through guided inquiry. The model organisms will be the basis for studying the four high school life science core ideas as identified by the Next Generation Science Standards (NGSS): LS1-From molecules to organisms, LS2-Ecosystems, LS3- Heredity, and LS4- Biological Evolution. NGSS also have identified four categories of science and engineering practices which include developing and using models and planning and carrying out investigations. The living organisms will be utilized to increase student interest and knowledge within the discipline of Biology. Pre-test and posttest analysis utilizing student t-test analysis supported the hypothesis. This study shows increased student learning as a result of using living organisms as models for classification and working in an inquiry-based learning environment.

  13. TGTG, G clustering and other signals near non-mammalian vertebrate mRNA 3' termini: some implications.

    Science.gov (United States)

    Nussinov, R

    1986-06-01

    Analysis of non-mammalian vertebrate DNA sequences in the 500 nucleotides preceding and 200 nucleotides following mRNA 3' termini yields some distinct signals. In addition to the well known AATAAA sequence, TGTG recurs very frequently further downstream. GGGG, TGGG, GGAG and GAGG are frequent in this region too. It is suggested that unlike the AATAAA mRNA cleavage/processing signal, the other signals noted above are signals on the DNA, i.e. they are signals for mRNA termination. An asymmetric distribution of some complementary sequences, e.g. TGTG vs. CACA, GGGG vs. CCCC, on the same DNA strand is noted as well. A few other signals are also observed.

  14. IDENTIFICATION AND CHARACTERIZATION OF DOPAMINE D4 RECEPTOR (DRD4 GENE SEQUENCE WITHIN AND AMONG NON MAMMALIAN SPECIES

    Directory of Open Access Journals (Sweden)

    Shikha Khandelwal

    2013-08-01

    Full Text Available A number of polymorphic tandem repeats in human dopamine D4 receptor (DRD4 have been identified in the exons, including a 12-bp repeat in the first exon and a 48-bp repeat in exon III located in the third cytoplasmic loop. However, to determine whether the tandem repeats is specific to humans or not, we have identified and characterized dopamine receptor D4 (DRD4 Exon III tandem repeats in public available nucleotide sequences from 13 different non mammalian species. We found that the tandem repeat was composed of 21-bp modules in sequences from the Mycobacterium smegmatis str. MC2 155, Salinibacter ruber DSM 13855, Danio rerio, Parus major, Corvus macrorhynchos, and Coturnix japonica. A tandem repeat consisting of 30-bp modules was identified in sequence from Melopsittacus undulates while in the Phalacrocorax capillatus and Numida meleagris we identified tandem repeats composed of 3-bp modules. Tandem repeats could not be identified in sequences from Carassius auratus, Phasianus colchicus and Gallus gallus. To understand the evolutionary history of the Exon I region of DRD4—which in humans contains a polymorphic 12bp tandem duplication, a polymorphic 13bp deletion, and other rare variants—we examined the homologous exon in these different species. There was a low degree of similarity between the sequences of bacterial species and those from members of the piscean and avian and with human sequence. We identified transmembrane domain of DRD4 gene and signature of G-protein coupled receptors in the amino acid sequences. The number of transmembrane segments varied pronouncedly between species from 0 to 7 and signature of G-protein coupled receptors was found only in piscean species and was also identified in one avian species (parus major. These findings suggest that an association between Drd4 gene polymorphisms and animal personality variation predates the divergence of the non mammalian and mammalian lineages. Furthermore, the analysis of

  15. The autonomic nervous system and chromaffin tissue: neuroendocrine regulation of catecholamine secretion in non-mammalian vertebrates.

    Science.gov (United States)

    Perry, Steve F; Capaldo, Anna

    2011-11-16

    If severe enough, periods of acute stress in animals may be associated with the release of catecholamine hormones (noradrenaline and adrenaline) into the circulation; a response termed the acute humoral adrenergic stress response. The release of catecholamines from the sites of storage, the chromaffin cells, is under neuroendocrine control, the complexity of which appears to increase through phylogeny. In the agnathans, the earliest branching vertebrates, the chromaffin cells which are localized predominantly within the heart, lack neuronal innervation and thus catecholamine secretion in these animals is initiated solely by humoral mechanisms. In the more advanced teleost fish, the chromaffin cells are largely confined to the walls of the posterior cardinal vein at the level of the head kidney where they are intermingled with the steroidogenic interrenal cells. Catecholamine secretion from teleost chromaffin cells is regulated by a host of cholinergic and non-cholinergic pathways that ensure sufficient redundancy and flexibility in the secretion process to permit synchronized responses to a myriad of stressors. The complexity of catecholamine secretion control mechanisms continues through the amphibians, reptiles and birds although neural (cholinergic) regulation may become increasingly important in birds. Discrete adrenal glands are present in the non-mammalian tetrapods but unlike in mammals, there is no clear division of a steroidogenic cortex and a chromaffin cell enriched medulla. However, in all groups, there is an obvious intermingling of chromaffin and steroiodogenic cells. The association of the two cell types may be particularly important in the amphibians and birds because like in mammals, the enzyme catalysing the methylation of noradrenaline to adrenaline, PNMT, is under the control of the steroid cortisol.

  16. Model Organisms Fact Sheet: Using Model Organisms to Study Health and Disease

    Science.gov (United States)

    ... Model Organisms to Study Health and Disease Using Model Organisms to Study Health and Disease Tagline (Optional) ... and treating disease in humans. What is a model? The word model has many meanings, but in ...

  17. Organization customer behavior: Elected models

    Directory of Open Access Journals (Sweden)

    Maričić Branko

    2008-01-01

    Full Text Available Paper is dealing with business-to-business marketing issues with particular attention to some of models oriented to explain differences relative to FMCG marketing. Author describe the core principles of selected models including their basic features. In this paper some of models are in focus - Window and Webster-Window model as well as Sheets model, Nielsen model and Multivariation tools.

  18. Dynamics models of soil organic carbon

    Institute of Scientific and Technical Information of China (English)

    YANGLi-xia; PANJian-jun

    2003-01-01

    As the largest pool of terrestrial organic carbon, soils interact strongly with atmosphere composition, climate, and land change. Soil organic carbon dynamics in ecosystem plays a great role in global carbon cycle and global change. With development of mathematical models that simulate changes in soil organic carbon, there have been considerable advances in understanding soil organic carbon dynamics. This paper mainly reviewed the composition of soil organic matter and its influenced factors, and recommended some soil organic matter models worldwide. Based on the analyses of the developed results at home and abroad, it is suggested that future soil organic matter models should be developed toward based-process models, and not always empirical ones. The models are able to reveal their interaction between soil carbon systems, climate and land cover by technique and methods of GIS (Geographical Information System) and RS (Remote Sensing). These models should be developed at a global scale, in dynamically describing the spatial and temporal changes of soil organic matter cycle. Meanwhile, the further researches on models should be strengthen for providing theory basis and foundation in making policy of green house gas emission in China.

  19. Project-matrix models of marketing organization

    Directory of Open Access Journals (Sweden)

    Gutić Dragutin

    2009-01-01

    Full Text Available Unlike theory and practice of corporation organization, in marketing organization numerous forms and contents at its disposal are not reached until this day. It can be well estimated that marketing organization today in most of our companies and in almost all its parts, noticeably gets behind corporation organization. Marketing managers have always been occupied by basic, narrow marketing activities as: sales growth, market analysis, market growth and market share, marketing research, introduction of new products, modification of products, promotion, distribution etc. They rarely found it necessary to focus a bit more to different aspects of marketing management, for example: marketing planning and marketing control, marketing organization and leading. This paper deals with aspects of project - matrix marketing organization management. Two-dimensional and more-dimensional models are presented. Among two-dimensional, these models are analyzed: Market management/products management model; Products management/management of product lifecycle phases on market model; Customers management/marketing functions management model; Demand management/marketing functions management model; Market positions management/marketing functions management model. .

  20. Cardiac Electromechanical Models: From Cell to Organ

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    Natalia A Trayanova

    2011-08-01

    Full Text Available The heart is a multiphysics and multiscale system that has driven the development of the most sophisticated mathematical models at the frontiers of computation physiology and medicine. This review focuses on electromechanical (EM models of the heart from the molecular level of myofilaments to anatomical models of the organ. Because of the coupling in terms of function and emergent behaviors at each level of biological hierarchy, separation of behaviors at a given scale is difficult. Here, a separation is drawn at the cell level so that the first half addresses subcellular/single cell models and the second half addresses organ models. At the subcelluar level, myofilament models represent actin-myosin interaction and Ca-based activation. Myofilament models and their refinements represent an overview of the development in the field. The discussion of specific models emphasizes the roles of cooperative mechanisms and sarcomere length dependence of contraction force, considered the cellular basis of the Frank-Starling law. A model of electrophysiology and Ca handling can be coupled to a myofilament model to produce an EM cell model, and representative examples are summarized to provide an overview of the progression of field. The second half of the review covers organ-level models that require solution of the electrical component as a reaction-diffusion system and the mechanical component, in which active tension generated by the myocytes produces deformation of the organ as described by the equations of continuum mechanics. As outlined in the review, different organ-level models have chosen to use different ionic and myofilament models depending on the specific application; this choice has been largely dictated by compromises between model complexity and computational tractability. The review also addresses application areas of EM models such as cardiac resynchronization therapy and the role of mechano-electric coupling in arrhythmias and

  1. The Zebrafish Model Organism Database (ZFIN)

    Data.gov (United States)

    U.S. Department of Health & Human Services — ZFIN serves as the zebrafish model organism database. It aims to: a) be the community database resource for the laboratory use of zebrafish, b) develop and support...

  2. Modeling Virtual Organization Architecture with the Virtual Organization Breeding Methodology

    Science.gov (United States)

    Paszkiewicz, Zbigniew; Picard, Willy

    While Enterprise Architecture Modeling (EAM) methodologies become more and more popular, an EAM methodology tailored to the needs of virtual organizations (VO) is still to be developed. Among the most popular EAM methodologies, TOGAF has been chosen as the basis for a new EAM methodology taking into account characteristics of VOs presented in this paper. In this new methodology, referred as Virtual Organization Breeding Methodology (VOBM), concepts developed within the ECOLEAD project, e.g. the concept of Virtual Breeding Environment (VBE) or the VO creation schema, serve as fundamental elements for development of VOBM. VOBM is a generic methodology that should be adapted to a given VBE. VOBM defines the structure of VBE and VO architectures in a service-oriented environment, as well as an architecture development method for virtual organizations (ADM4VO). Finally, a preliminary set of tools and methods for VOBM is given in this paper.

  3. Modeling Virtual Organization Architecture with the Virtual Organization Breeding Methodology

    CERN Document Server

    Paszkiewicz, Zbigniew

    2011-01-01

    While Enterprise Architecture Modeling (EAM) methodologies become more and more popular, an EAM methodology tailored to the needs of virtual organizations (VO) is still to be developed. Among the most popular EAM methodologies, TOGAF has been chosen as the basis for a new EAM methodology taking into account characteristics of VOs presented in this paper. In this new methodology, referred as Virtual Organization Breeding Methodology (VOBM), concepts developed within the ECOLEAD project, e.g. the concept of Virtual Breeding Environment (VBE) or the VO creation schema, serve as fundamental elements for development of VOBM. VOBM is a generic methodology that should be adapted to a given VBE. VOBM defines the structure of VBE and VO architectures in a service-oriented environment, as well as an architecture development method for virtual organizations (ADM4VO). Finally, a preliminary set of tools and methods for VOBM is given in this paper.

  4. Modeling personnel turnover in the parametric organization

    Science.gov (United States)

    Dean, Edwin B.

    1991-01-01

    A model is developed for simulating the dynamics of a newly formed organization, credible during all phases of organizational development. The model development process is broken down into the activities of determining the tasks required for parametric cost analysis (PCA), determining the skills required for each PCA task, determining the skills available in the applicant marketplace, determining the structure of the model, implementing the model, and testing it. The model, parameterized by the likelihood of job function transition, has demonstrated by the capability to represent the transition of personnel across functional boundaries within a parametric organization using a linear dynamical system, and the ability to predict required staffing profiles to meet functional needs at the desired time. The model can be extended by revisions of the state and transition structure to provide refinements in functional definition for the parametric and extended organization.

  5. Complex Systems and Self-organization Modelling

    CERN Document Server

    Bertelle, Cyrille; Kadri-Dahmani, Hakima

    2009-01-01

    The concern of this book is the use of emergent computing and self-organization modelling within various applications of complex systems. The authors focus their attention both on the innovative concepts and implementations in order to model self-organizations, but also on the relevant applicative domains in which they can be used efficiently. This book is the outcome of a workshop meeting within ESM 2006 (Eurosis), held in Toulouse, France in October 2006.

  6. Condensing Organic Aerosols in a Microphysical Model

    Science.gov (United States)

    Gao, Y.; Tsigaridis, K.; Bauer, S.

    2015-12-01

    The condensation of organic aerosols is represented in a newly developed box-model scheme, where its effect on the growth and composition of particles are examined. We implemented the volatility-basis set (VBS) framework into the aerosol mixing state resolving microphysical scheme Multiconfiguration Aerosol TRacker of mIXing state (MATRIX). This new scheme is unique and advances the representation of organic aerosols in models in that, contrary to the traditional treatment of organic aerosols as non-volatile in most climate models and in the original version of MATRIX, this new scheme treats them as semi-volatile. Such treatment is important because low-volatility organics contribute significantly to the growth of particles. The new scheme includes several classes of semi-volatile organic compounds from the VBS framework that can partition among aerosol populations in MATRIX, thus representing the growth of particles via condensation of low volatility organic vapors. Results from test cases representing Mexico City and a Finish forrest condistions show good representation of the time evolutions of concentration for VBS species in the gas phase and in the condensed particulate phase. Emitted semi-volatile primary organic aerosols evaporate almost completely in the high volatile range, and they condense more efficiently in the low volatility range.

  7. Putting "Organizations" into an Organization Theory Course: A Hybrid CAO Model for Teaching Organization Theory

    Science.gov (United States)

    Hannah, David R.; Venkatachary, Ranga

    2010-01-01

    In this article, the authors present a retrospective analysis of an instructor's multiyear redesign of a course on organization theory into what is called a hybrid Classroom-as-Organization model. It is suggested that this new course design served to apprentice students to function in quasi-real organizational structures. The authors further argue…

  8. Web Resources for Model Organism Studies

    Institute of Scientific and Technical Information of China (English)

    Bixia Tang; Yanqing Wang; Junwei Zhu; Wenming Zhao

    2015-01-01

    An ever-growing number of resources on model organisms have emerged with the continued development of sequencing technologies. In this paper, we review 13 databases of model organisms, most of which are reported by the National Institutes of Health of the United States (NIH; http://www.nih.gov/science/models/). We provide a brief description for each database, as well as detail its data source and types, functions, tools, and availability of access. In addition, we also provide a quality assessment about these databases. Significantly, the organism databases instituted in the early 1990s––such as the Mouse Genome Database (MGD), Saccharomyces Genome Database (SGD), and FlyBase––have developed into what are now comprehensive, core authority resources. Furthermore, all of the databases mentioned here update continually according to user feedback and with advancing technologies.

  9. Mathematical Modeling Social Responsibility for Dynamic Organizations

    Directory of Open Access Journals (Sweden)

    Farzaneh Chavoshbashi

    2012-03-01

    Full Text Available Dynamic organizations as accountable organizations, for transparency and accountability to its stakeholders to stakeholders for their toward performance there should express their commitment to social responsibility are through their values and ensure that this commitment throughout the organization are now and thus will have a social responsibility for their mutual benefit, so there is more and more coherent in their ethical approach takes advantage and the community and stakeholders and the organization will have better performance and strengths. Because of interest in social responsibility, in this paper dynamic model is presented for Corporate Social Responsibility of Bionic organization. Model presented a new model is inspired by chaos theory and natural systems theory based on bifurcation in creation to be all natural systems, realizing the value of responsibility as one of the fundamental values of social and institutional development that the relationship between business and work environment in the global market economy and range will be specified. First Social Responsibility factors identified, then experts and scholars determine the weight of the components and technical coefficient for modeling and paired comparison has been done using MATLAB mathematical Software.

  10. Polymer models of chromosome (re)organization

    Science.gov (United States)

    Mirny, Leonid

    Chromosome Conformation Capture technique (Hi-C) provides comprehensive information about frequencies of spatial interactions between genomic loci. Inferring 3D organization of chromosomes from these data is a challenging biophysical problem. We develop a top-down approach to biophysical modeling of chromosomes. Starting with a minimal set of biologically motivated interactions we build ensembles of polymer conformations that can reproduce major features observed in Hi-C experiments. I will present our work on modeling organization of human metaphase and interphase chromosomes. Our works suggests that active processes of loop extrusion can be a universal mechanism responsible for formation of domains in interphase and chromosome compaction in metaphase.

  11. Microtechnology-Based Multi-Organ Models

    Directory of Open Access Journals (Sweden)

    Seung Hwan Lee

    2017-05-01

    Full Text Available Drugs affect the human body through absorption, distribution, metabolism, and elimination (ADME processes. Due to their importance, the ADME processes need to be studied to determine the efficacy and side effects of drugs. Various in vitro model systems have been developed and used to realize the ADME processes. However, conventional model systems have failed to simulate the ADME processes because they are different from in vivo, which has resulted in a high attrition rate of drugs and a decrease in the productivity of new drug development. Recently, a microtechnology-based in vitro system called “organ-on-a-chip” has been gaining attention, with more realistic cell behavior and physiological reactions, capable of better simulating the in vivo environment. Furthermore, multi-organ-on-a-chip models that can provide information on the interaction between the organs have been developed. The ultimate goal is the development of a “body-on-a-chip”, which can act as a whole body model. In this review, we introduce and summarize the current progress in the development of multi-organ models as a foundation for the development of body-on-a-chip.

  12. Microtechnology-Based Multi-Organ Models.

    Science.gov (United States)

    Lee, Seung Hwan; Sung, Jong Hwan

    2017-05-21

    Drugs affect the human body through absorption, distribution, metabolism, and elimination (ADME) processes. Due to their importance, the ADME processes need to be studied to determine the efficacy and side effects of drugs. Various in vitro model systems have been developed and used to realize the ADME processes. However, conventional model systems have failed to simulate the ADME processes because they are different from in vivo, which has resulted in a high attrition rate of drugs and a decrease in the productivity of new drug development. Recently, a microtechnology-based in vitro system called "organ-on-a-chip" has been gaining attention, with more realistic cell behavior and physiological reactions, capable of better simulating the in vivo environment. Furthermore, multi-organ-on-a-chip models that can provide information on the interaction between the organs have been developed. The ultimate goal is the development of a "body-on-a-chip", which can act as a whole body model. In this review, we introduce and summarize the current progress in the development of multi-organ models as a foundation for the development of body-on-a-chip.

  13. New Federated Collaborative Networked Organization Model (FCNOM

    Directory of Open Access Journals (Sweden)

    Morcous M. Yassa

    2012-01-01

    Full Text Available Formation of Collaborative Networked Organization (CNO usually comes upon expected business opportunities and needs huge of negotiation during its lifecycle, especially to increase the Dynamic Virtual Organization (DVO configuration automation. Decision makers need more comprehensive information about CNO system to support their decisions. Unfortunately, there is no single formal modeling, tool, approach or any comprehensive methodology that covers all perspectives. In spite of there are some approaches to model CNO have been existed, these approaches model the CNO either with respect to the technology, or business without considering organizational behavior, federation modeling, and external environments. The aim of this paper is to propose an integrated framework that combines the existed modeling perspectives, as well as, proposes new ones. Also, it provides clear CNO boundaries. By using this approach the view of CNO environment becomes clear and unified. Also, it minimizes the negotiations within CNO components during its life cycle, supports DVO configuration automation, as well as, helps decision making for DVO, and achieves harmonization between CNO partners. The proposed FCNOM utilizes CommonKADS methodology organization model for describing CNO components. Insurance Collaborative Network has been used as an example to proof the proposed FCNOM model.

  14. Organic production in a dynamic CGE model

    DEFF Research Database (Denmark)

    Jacobsen, Lars Bo

    2004-01-01

    Concerns about the impact of modern agriculture on the environment have in recent years led to an interest in supporting the development of organic farming. In addition to environmental benefits, the aim is to encourage the provision of other “multifunctional” properties of organic farming...... such as rural amenities and rural development that are spillover benefit additional to the supply of food. In this paper we further develop an existing dynamic general equilibrium model of the Danish economy to specifically incorporate organic farming. In the model and input-output data each primary...... to illustrate the working of our theory by constructing a long term forecast for the development of the Danish economy. Moreover we simulate the effect of the recent agreed 2003 reform of the common agricultural policy....

  15. Safety Cultural Competency Modeling in Nuclear Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sa Kil; Oh, Yeon Ju; Luo, Meiling; Lee, Yong Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The nuclear safety cultural competency model should be supplemented through a bottom-up approach such as behavioral event interview. The developed model, however, is meaningful for determining what should be dealt for enhancing safety cultural competency of nuclear organizations. The more details of the developing process, results, and applications will be introduced later. Organizational culture include safety culture in terms of its organizational characteristics.

  16. Expanding on Successful Concepts, Models, and Organization

    Science.gov (United States)

    If the goal of the AEP framework was to replace existing exposure models or databases for organizing exposure data with a concept, we would share Dr. von Göetz concerns. Instead, the outcome we promote is broader use of an organizational framework for exposure science. The f...

  17. Emergent organization in a model market

    Science.gov (United States)

    Yadav, Avinash Chand; Manchanda, Kaustubh; Ramaswamy, Ramakrishna

    2017-09-01

    We study the collective behaviour of interacting agents in a simple model of market economics that was originally introduced by Nørrelykke and Bak. A general theoretical framework for interacting traders on an arbitrary network is presented, with the interaction consisting of buying (namely consumption) and selling (namely production) of commodities. Extremal dynamics is introduced by having the agent with least profit in the market readjust prices, causing the market to self-organize. In addition to examining this model market on regular lattices in two-dimensions, we also study the cases of random complex networks both with and without community structures. Fluctuations in an activity signal exhibit properties that are characteristic of avalanches observed in models of self-organized criticality, and these can be described by power-law distributions when the system is in the critical state.

  18. Emergent organization in a model market

    CERN Document Server

    Yadav, Avinash Chand; Ramaswamy, Ramakrishna

    2016-01-01

    We study the collective behavior of interacting agents in a simple model of market economics originally introduced by N{\\o}rrelykke and Bak. A general theoretical framework for interacting traders on an arbitrary network is presented, with the interaction consisting of buying (namely, consumption) and selling (namely, production) of commodities. Extremal dynamics is introduced by having the agent with least profit in the market readjust prices, causing the market to self--organize. We study this model market on regular lattices in two--dimension as well as on random complex networks; in the critical state fluctuations in an activity signal exhibit properties that are characteristic of avalanches observed in models of self-organized criticality, and these can be described by power--law distributions.

  19. Self-organized model of cascade spreading

    Science.gov (United States)

    Gualdi, S.; Medo, M.; Zhang, Y.-C.

    2011-01-01

    We study simultaneous price drops of real stocks and show that for high drop thresholds they follow a power-law distribution. To reproduce these collective downturns, we propose a minimal self-organized model of cascade spreading based on a probabilistic response of the system elements to stress conditions. This model is solvable using the theory of branching processes and the mean-field approximation. For a wide range of parameters, the system is in a critical state and displays a power-law cascade-size distribution similar to the empirically observed one. We further generalize the model to reproduce volatility clustering and other observed properties of real stocks.

  20. Recursive self-organizing network models.

    Science.gov (United States)

    Hammer, Barbara; Micheli, Alessio; Sperduti, Alessandro; Strickert, Marc

    2004-01-01

    Self-organizing models constitute valuable tools for data visualization, clustering, and data mining. Here, we focus on extensions of basic vector-based models by recursive computation in such a way that sequential and tree-structured data can be processed directly. The aim of this article is to give a unified review of important models recently proposed in literature, to investigate fundamental mathematical properties of these models, and to compare the approaches by experiments. We first review several models proposed in literature from a unifying perspective, thereby making use of an underlying general framework which also includes supervised recurrent and recursive models as special cases. We shortly discuss how the models can be related to different neuron lattices. Then, we investigate theoretical properties of the models in detail: we explicitly formalize how structures are internally stored in different context models and which similarity measures are induced by the recursive mapping onto the structures. We assess the representational capabilities of the models, and we shortly discuss the issues of topology preservation and noise tolerance. The models are compared in an experiment with time series data. Finally, we add an experiment for one context model for tree-structured data to demonstrate the capability to process complex structures.

  1. Modeling plasmonic efficiency enhancement in organic photovoltaics.

    Science.gov (United States)

    Taff, Y; Apter, B; Katz, E A; Efron, U

    2015-09-10

    Efficiency enhancement of bulk heterojunction (BHJ) organic solar cells by means of the plasmonic effect is investigated by using finite-difference time-domain (FDTD) optical simulations combined with analytical modeling of exciton dissociation and charge transport efficiencies. The proposed method provides an improved analysis of the cell performance compared to previous FDTD studies. The results of the simulations predict an 11.8% increase in the cell's short circuit current with the use of Ag nano-hexagons.

  2. Self-organized model of cascade spreading

    CERN Document Server

    Gualdi, Stanislao; Zhang, Yi-Cheng

    2010-01-01

    We study simultaneous price drops of real stocks and show that for high drop thresholds they follow a power-law distribution. To reproduce these collective downturns, we propose a self-organized model of cascade spreading based on a probabilistic response of the system's elements to stress conditions. This model is solvable using the theory of branching processes and the mean-field approximation and displays a power-law cascade-size distribution-similar to the empirically observed one-over a wide range of parameters.

  3. MODEL ORGANISMS USED IN MOLECULAR BIOLOGY OR MEDICAL RESEARCH

    OpenAIRE

    Pandey Govind

    2011-01-01

    A model organism is a non-human species that is studied to understand specific biological phenomena with the expectation that investigations made in the organism model will provide insight into the workings of other organisms. The model organisms are widely used to explore potential causes and treatments for human as well as animal diseases when experiments on animals or humans would be unfeasible or considered less ethical. Studying model organisms may be informative, but care must be taken ...

  4. Expanding on Successful Concepts, Models, and Organization

    Energy Technology Data Exchange (ETDEWEB)

    Teeguarden, Justin G.; Tan, Yu-Mei; Edwards, Stephen W.; Leonard, Jeremy A.; Anderson, Kim A.; Corley, Richard A.; Kile, Molly L.; L. Massey Simonich, Staci; Stone, David; Tanguay, Robert L.; Waters, Katrina M.; Harper, Stacey L.; Williams, David E.

    2016-09-06

    In her letter to the editor1 regarding our recent Feature Article “Completing the Link between Exposure Science and Toxicology for Improved Environmental Health Decision Making: The Aggregate Exposure Pathway Framework” 2, Dr. von Göetz expressed several concerns about terminology, and the perception that we propose the replacement of successful approaches and models for exposure assessment with a concept. We are glad to have the opportunity to address these issues here. If the goal of the AEP framework was to replace existing exposure models or databases for organizing exposure data with a concept, we would share Dr. von Göetz concerns. Instead, the outcome we promote is broader use of an organizational framework for exposure science. The framework would support improved generation, organization, and interpretation of data as well as modeling and prediction, not replacement of models. The field of toxicology has seen the benefits of wide use of one or more organizational frameworks (e.g., mode and mechanism of action, adverse outcome pathway). These frameworks influence how experiments are designed, data are collected, curated, stored and interpreted and ultimately how data are used in risk assessment. Exposure science is poised to similarly benefit from broader use of a parallel organizational framework, which Dr. von Göetz correctly points out, is currently used in the exposure modeling community. In our view, the concepts used so effectively in the exposure modeling community, expanded upon in the AEP framework, could see wider adoption by the field as a whole. The value of such a framework was recognized by the National Academy of Sciences.3 Replacement of models, databases, or any application with the AEP framework was not proposed in our article. The positive role broader more consistent use of such a framework might have in enabling and advancing “general activities such as data acquisition, organization…,” and exposure modeling was discussed

  5. Modeling disordered morphologies in organic semiconductors.

    Science.gov (United States)

    Neumann, Tobias; Danilov, Denis; Lennartz, Christian; Wenzel, Wolfgang

    2013-12-05

    Organic thin film devices are investigated for many diverse applications, including light emitting diodes, organic photovoltaic and organic field effect transistors. Modeling of their properties on the basis of their detailed molecular structure requires generation of representative morphologies, many of which are amorphous. Because time-scales for the formation of the molecular structure are slow, we have developed a linear-scaling single molecule deposition protocol which generates morphologies by simulation of vapor deposition of molecular films. We have applied this protocol to systems comprising argon, buckminsterfullerene, N,N-Di(naphthalene-1-yl)-N,N'-diphenyl-benzidine, mer-tris(8-hydroxy-quinoline)aluminum(III), and phenyl-C61-butyric acid methyl ester, with and without postdeposition relaxation of the individually deposited molecules. The proposed single molecule deposition protocol leads to formation of highly ordered morphologies in argon and buckminsterfullerene systems when postdeposition relaxation is used to locally anneal the configuration in the vicinity of the newly deposited molecule. The other systems formed disordered amorphous morphologies and the postdeposition local relaxation step has only a small effect on the characteristics of the disordered morphology in comparison to the materials forming crystals.

  6. Virtuous organization: A structural equation modeling approach

    Directory of Open Access Journals (Sweden)

    Majid Zamahani

    2013-02-01

    Full Text Available For years, the idea of virtue was unfavorable among researchers and virtues were traditionally considered as culture-specific, relativistic and they were supposed to be associated with social conservatism, religious or moral dogmatism, and scientific irrelevance. Virtue and virtuousness have been recently considered seriously among organizational researchers. The proposed study of this paper examines the relationships between leadership, organizational culture, human resource, structure and processes, care for community and virtuous organization. Structural equation modeling is employed to investigate the effects of each variable on other components. The data used in this study consists of questionnaire responses from employees in Payam e Noor University in Yazd province. A total of 250 questionnaires were sent out and a total of 211 valid responses were received. Our results have revealed that all the five variables have positive and significant impacts on virtuous organization. Among the five variables, organizational culture has the most direct impact (0.80 and human resource has the most total impact (0.844 on virtuous organization.

  7. Organic acid modeling and model validation: Workshop summary. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T.J.; Eilers, J.M.

    1992-08-14

    A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E&S Environmental Chemistry, Inc. The purpose of this workshop was to initiate research efforts on the entitled ``Incorporation of an organic acid representation into MAGIC (Model of Acidification of Groundwater in Catchments) and testing of the revised model using Independent data sources.`` The workshop was attended by a team of internationally-recognized experts in the fields of surface water acid-bass chemistry, organic acids, and watershed modeling. The rationale for the proposed research is based on the recent comparison between MAGIC model hindcasts and paleolimnological inferences of historical acidification for a set of 33 statistically-selected Adirondack lakes. Agreement between diatom-inferred and MAGIC-hindcast lakewater chemistry in the earlier research had been less than satisfactory. Based on preliminary analyses, it was concluded that incorporation of a reasonable organic acid representation into the version of MAGIC used for hindcasting was the logical next step toward improving model agreement.

  8. Organic acid modeling and model validation: Workshop summary

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T.J.; Eilers, J.M.

    1992-08-14

    A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E S Environmental Chemistry, Inc. The purpose of this workshop was to initiate research efforts on the entitled Incorporation of an organic acid representation into MAGIC (Model of Acidification of Groundwater in Catchments) and testing of the revised model using Independent data sources.'' The workshop was attended by a team of internationally-recognized experts in the fields of surface water acid-bass chemistry, organic acids, and watershed modeling. The rationale for the proposed research is based on the recent comparison between MAGIC model hindcasts and paleolimnological inferences of historical acidification for a set of 33 statistically-selected Adirondack lakes. Agreement between diatom-inferred and MAGIC-hindcast lakewater chemistry in the earlier research had been less than satisfactory. Based on preliminary analyses, it was concluded that incorporation of a reasonable organic acid representation into the version of MAGIC used for hindcasting was the logical next step toward improving model agreement.

  9. Modeling charge transport in organic photovoltaic materials.

    Science.gov (United States)

    Nelson, Jenny; Kwiatkowski, Joe J; Kirkpatrick, James; Frost, Jarvist M

    2009-11-17

    The performance of an organic photovoltaic cell depends critically on the mobility of charge carriers within the constituent molecular semiconductor materials. However, a complex combination of phenomena that span a range of length and time scales control charge transport in disordered organic semiconductors. As a result, it is difficult to rationalize charge transport properties in terms of material parameters. Until now, efforts to improve charge mobilities in molecular semiconductors have proceeded largely by trial and error rather than through systematic design. However, recent developments have enabled the first predictive simulation studies of charge transport in disordered organic semiconductors. This Account describes a set of computational methods, specifically molecular modeling methods, to simulate molecular packing, quantum chemical calculations of charge transfer rates, and Monte Carlo simulations of charge transport. Using case studies, we show how this combination of methods can reproduce experimental mobilities with few or no fitting parameters. Although currently applied to material systems of high symmetry or well-defined structure, further developments of this approach could address more complex systems such anisotropic or multicomponent solids and conjugated polymers. Even with an approximate treatment of packing disorder, these computational methods simulate experimental mobilities within an order of magnitude at high electric fields. We can both reproduce the relative values of electron and hole mobility in a conjugated small molecule and rationalize those values based on the symmetry of frontier orbitals. Using fully atomistic molecular dynamics simulations of molecular packing, we can quantitatively replicate vertical charge transport along stacks of discotic liquid crystals which vary only in the structure of their side chains. We can reproduce the trends in mobility with molecular weight for self-organizing polymers using a cheap, coarse

  10. A new atmospheric aerosol phase equilibrium model (UHAERO: organic systems

    Directory of Open Access Journals (Sweden)

    N. R. Amundson

    2007-09-01

    Full Text Available In atmospheric aerosols, water and volatile inorganic and organic species are distributed between the gas and aerosol phases in accordance with thermodynamic equilibrium. Within an atmospheric particle, liquid and solid phases can exist at equilibrium. Models exist for computation of phase equilibria for inorganic/water mixtures typical of atmospheric aerosols; when organic species are present, the phase equilibrium problem is complicated by organic/water interactions as well as the potentially large number of organic species. We present here an extension of the UHAERO inorganic thermodynamic model (Amundson et al., 2006c to organic/water systems. Phase diagrams for a number of model organic/water systems characteristic of both primary and secondary organic aerosols are computed. Also calculated are inorganic/organic/water phase diagrams that show the effect of organics on inorganic deliquescence behavior. The effect of the choice of activity coefficient model for organics on the computed phase equilibria is explored.

  11. A new atmospheric aerosol phase equilibrium model (UHAERO: organic systems

    Directory of Open Access Journals (Sweden)

    N. R. Amundson

    2007-06-01

    Full Text Available In atmospheric aerosols, water and volatile inorganic and organic species are distributed between the gas and aerosol phases in accordance with thermodynamic equilibrium. Within an atmospheric particle, liquid and solid phases can exist at equilibrium. Models exist for computation of phase equilibria for inorganic/water mixtures typical of atmospheric aerosols; when organic species are present, the phase equilibrium problem is complicated by organic/water interactions as well as the potentially large number of organic species. We present here an extension of the UHAERO inorganic thermodynamic model (Amundson et al., 2006c to organic/water systems. Phase diagrams for a number of model organic/water systems characteristic of both primary and secondary organic aerosols are computed. Also calculated are inorganic/organic/water phase diagrams that show the effect of organics on inorganic deliquescence behavior. The effect of the choice of activity coefficient model for organics on the computed phase equilibria is explored.

  12. Model for Railway Infrastructure Management Organization

    Directory of Open Access Journals (Sweden)

    Gordan Stojić

    2012-03-01

    Full Text Available The provision of appropriate quality rail services has an important role in terms of railway infrastructure: quality of infrastructure maintenance, regulation of railway traffic, line capacity, speed, safety, train station organization, the allowable lines load and other infrastructure parameters.The analysis of experiences in transforming the railway systems points to the conclusion that there is no unique solution in terms of choice for institutional rail infrastructure management modes, although more than nineteen years have passed from the beginning of the implementation of the Directive 91/440/EEC. Depending on the approach to the process of restructuring the national railway company, adopted regulations and caution in its implementation, the existence or absence of a clearly defined transport strategy, the willingness to liberalize the transport market, there are several different ways for institutional management of railway infrastructure.A hybrid model for selection of modes of institutional rail infrastructure management was developed based on the theory of artificial intelligence, theory of fuzzy sets and theory of multicriteria optimization.KEY WORDSmanagement, railway infrastructure, organizational structure, hybrid model

  13. Knowledge Management Model on Educational Organization

    Directory of Open Access Journals (Sweden)

    Elsina Ferdinandus

    2015-12-01

    Key Words: model, knowledge management, educational organizations Abstrak: Penelitian ini bertujuan mendeskripsikan proses knowledge management yang dilakukan pada SMA Negeri 1 Pulau-pulau Aru dan SMA Yos Sudarso Dobo di Kabupaten Kepulauan Aru. Penelitian ini menggunakan jenis penelitian kualitatif dengan rancangan studi multi kasus. Data dikumpulkan dengan teknik observasi, wawancara mendalam dan dokumentasi kemudian dianalisis dengan teknik analisis data kasus individu dan analisis data lintas kasus. Temuan penelitian ini menggambarkan (1 guru-guru sudah melakukan transformasi pengetahuan explicit to tacit dengan baik ketika melakukan persiapan pembelajaran, transformasi pengetahuan tacit to explicit belum dilakukan dengan baik, dan transformasi pengetahuan tacit to tacit sudah dilakukan dengan baik; (2  sosialisasi dilakukan dengan baik, namun belum maksimal; (3  kepala sekolah SMA Negeri 1 Pulau-pulau Aru lebih demokratis dan kepala sekolah SMA Yos Sudarso Dobo lebih paternalistis; (4 peningkatan berupa upaya memasukan pengetahuan dari luar sekolah sudah dilakukan oleh kedua sekolah; dan (5  proses knowledge capture di kedua sekolah sudah berjalan dengan baik. Kata kunci: model, knowledge management, organisasi pendidikan

  14. COMPUTER MODEL FOR ORGANIC FERTILIZER EVALUATION

    Directory of Open Access Journals (Sweden)

    Zdenko Lončarić

    2009-12-01

    Full Text Available Evaluation of manures, composts and growing media quality should include enough properties to enable an optimal use from productivity and environmental points of view. The aim of this paper is to describe basic structure of organic fertilizer (and growing media evaluation model to present the model example by comparison of different manures as well as example of using plant growth experiment for calculating impact of pH and EC of growing media on lettuce plant growth. The basic structure of the model includes selection of quality indicators, interpretations of indicators value, and integration of interpreted values into new indexes. The first step includes data input and selection of available data as a basic or additional indicators depending on possible use as fertilizer or growing media. The second part of the model uses inputs for calculation of derived quality indicators. The third step integrates values into three new indexes: fertilizer, growing media, and environmental index. All three indexes are calculated on the basis of three different groups of indicators: basic value indicators, additional value indicators and limiting factors. The possible range of indexes values is 0-10, where range 0-3 means low, 3-7 medium and 7-10 high quality. Comparing fresh and composted manures, higher fertilizer and environmental indexes were determined for composted manures, and the highest fertilizer index was determined for composted pig manure (9.6 whereas the lowest for fresh cattle manure (3.2. Composted manures had high environmental index (6.0-10 for conventional agriculture, but some had no value (environmental index = 0 for organic agriculture because of too high zinc, copper or cadmium concentrations. Growing media indexes were determined according to their impact on lettuce growth. Growing media with different pH and EC resulted in very significant impacts on height, dry matter mass and leaf area of lettuce seedlings. The highest lettuce

  15. Formal Modelling of Goals in Organizations

    NARCIS (Netherlands)

    Popova, Viara; Sharpanskykh, Alexei

    2008-01-01

    Each organization exists or is created for the achievement of one or more goals. To ensure continued success, the organization should monitor its performance with respect to the formulated goals. In practice the performance of an organization is often evaluated by estimating its performance indicato

  16. The Time Is Right to Focus on Model Organism Metabolomes

    Directory of Open Access Journals (Sweden)

    Arthur S. Edison

    2016-02-01

    Full Text Available Model organisms are an essential component of biological and biomedical research that can be used to study specific biological processes. These organisms are in part selected for facile experimental study. However, just as importantly, intensive study of a small number of model organisms yields important synergies as discoveries in one area of science for a given organism shed light on biological processes in other areas, even for other organisms. Furthermore, the extensive knowledge bases compiled for each model organism enable systems-level understandings of these species, which enhance the overall biological and biomedical knowledge for all organisms, including humans. Building upon extensive genomics research, we argue that the time is now right to focus intensively on model organism metabolomes. We propose a grand challenge for metabolomics studies of model organisms: to identify and map all metabolites onto metabolic pathways, to develop quantitative metabolic models for model organisms, and to relate organism metabolic pathways within the context of evolutionary metabolomics, i.e., phylometabolomics. These efforts should focus on a series of established model organisms in microbial, animal and plant research.

  17. The Time Is Right to Focus on Model Organism Metabolomes

    Science.gov (United States)

    Edison, Arthur S.; Hall, Robert D.; Junot, Christophe; Karp, Peter D.; Kurland, Irwin J.; Mistrik, Robert; Reed, Laura K.; Saito, Kazuki; Salek, Reza M.; Steinbeck, Christoph; Sumner, Lloyd W.; Viant, Mark R.

    2016-01-01

    Model organisms are an essential component of biological and biomedical research that can be used to study specific biological processes. These organisms are in part selected for facile experimental study. However, just as importantly, intensive study of a small number of model organisms yields important synergies as discoveries in one area of science for a given organism shed light on biological processes in other areas, even for other organisms. Furthermore, the extensive knowledge bases compiled for each model organism enable systems-level understandings of these species, which enhance the overall biological and biomedical knowledge for all organisms, including humans. Building upon extensive genomics research, we argue that the time is now right to focus intensively on model organism metabolomes. We propose a grand challenge for metabolomics studies of model organisms: to identify and map all metabolites onto metabolic pathways, to develop quantitative metabolic models for model organisms, and to relate organism metabolic pathways within the context of evolutionary metabolomics, i.e., phylometabolomics. These efforts should focus on a series of established model organisms in microbial, animal and plant research. PMID:26891337

  18. The Time Is Right to Focus on Model Organism Metabolomes

    NARCIS (Netherlands)

    Edison, Arthur; Hall, Robert; Junot, Christophe; Karp, Peter; Kurland, Irwin; Mistrik, Robert; Reed, Laura; Saito, Kazuki; Salek, Reza; Steinbeck, Christoph; Sumner, Lloyd; Viant, Mark

    2016-01-01

    Model organisms are an essential component of biological and biomedical research that can be used to study specific biological processes. These organisms are in part selected for facile experimental study. However, just as importantly, intensive study of a small number of model organisms yields

  19. The Time Is Right to Focus on Model Organism Metabolomes.

    Science.gov (United States)

    Edison, Arthur S; Hall, Robert D; Junot, Christophe; Karp, Peter D; Kurland, Irwin J; Mistrik, Robert; Reed, Laura K; Saito, Kazuki; Salek, Reza M; Steinbeck, Christoph; Sumner, Lloyd W; Viant, Mark R

    2016-02-15

    Model organisms are an essential component of biological and biomedical research that can be used to study specific biological processes. These organisms are in part selected for facile experimental study. However, just as importantly, intensive study of a small number of model organisms yields important synergies as discoveries in one area of science for a given organism shed light on biological processes in other areas, even for other organisms. Furthermore, the extensive knowledge bases compiled for each model organism enable systems-level understandings of these species, which enhance the overall biological and biomedical knowledge for all organisms, including humans. Building upon extensive genomics research, we argue that the time is now right to focus intensively on model organism metabolomes. We propose a grand challenge for metabolomics studies of model organisms: to identify and map all metabolites onto metabolic pathways, to develop quantitative metabolic models for model organisms, and to relate organism metabolic pathways within the context of evolutionary metabolomics, i.e., phylometabolomics. These efforts should focus on a series of established model organisms in microbial, animal and plant research.

  20. Self-Organized Criticality in a Random Network Model

    OpenAIRE

    Nirei, Makoto

    1998-01-01

    A new model of self-organized criticality is defined by incorporating a random network model in order to explain endogenous complex fluctuations of economic aggregates. The model can feature many globally interactive systems such as economies or societies.

  1. Study of Self-Organization Model of Multiple Mobile Robot

    OpenAIRE

    Li Shu-qin; Ceng Xian-yi; Xia De-shen

    2006-01-01

    A good organization model of multiple mobile robot should be able to improve the efficiency of the system, reduce the complication of robot interactions, and detract the difficulty of computation. From the sociology aspect of topology, structure and organization, this paper studies the multiple mobile robot organization formation and running mechanism in the dynamic, complicated and unknown environment. It presents and describes in detail a Hierarchical- Web Recursive Organization Model (HWRO...

  2. A Topological Model for C2 Organizations

    Science.gov (United States)

    2011-06-01

    functions of the organization, and the capabilities of its members, as these sets somehow efine the boundaries of organizational performance and the...and functions of the organization, and the capabilities of its members, as these sets somehow efine the boundaries of organizational performance and

  3. 3D Bioprinting of Tissue/Organ Models.

    Science.gov (United States)

    Pati, Falguni; Gantelius, Jesper; Svahn, Helene Andersson

    2016-04-04

    In vitro tissue/organ models are useful platforms that can facilitate systematic, repetitive, and quantitative investigations of drugs/chemicals. The primary objective when developing tissue/organ models is to reproduce physiologically relevant functions that typically require complex culture systems. Bioprinting offers exciting prospects for constructing 3D tissue/organ models, as it enables the reproducible, automated production of complex living tissues. Bioprinted tissues/organs may prove useful for screening novel compounds or predicting toxicity, as the spatial and chemical complexity inherent to native tissues/organs can be recreated. In this Review, we highlight the importance of developing 3D in vitro tissue/organ models by 3D bioprinting techniques, characterization of these models for evaluating their resemblance to native tissue, and their application in the prioritization of lead candidates, toxicity testing, and as disease/tumor models.

  4. using stereochemistry models in teaching organic compounds ...

    African Journals Online (AJOL)

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    (ii) provide the students with basic knowledge in chemical concepts and ... ethanol, ethan-l-ol and ethyl alcohol in some textbooks and they are the same. ... Considering class level, what is the performance of the students in naming organic.

  5. A Modeling Exercise for the Organic Classroom

    Science.gov (United States)

    Whitlock, Christine R.

    2010-01-01

    An in-class molecular modeling exercise is described. Groups of students are given molecular models to investigate and questions about the models to answer. This exercise is a quick and effective way to review nomenclature, stereochemistry, and conformational analysis.

  6. Self-Organizing Map Models of Language Acquisition

    Directory of Open Access Journals (Sweden)

    Ping eLi

    2013-11-01

    Full Text Available Connectionist models have had a profound impact on theories of language. While most early models were inspired by the classic PDP architecture, recent models of language have explored various other types of models, including self-organizing models for language acquisition. In this paper we aim at providing a review of the latter type of models, and highlight a number of simulation experiments that we have conducted based on these models. We show that self-organizing connectionist models can provide significant insights into long-standing debates in both monolingual and bilingual language development.

  7. MODELING OF MANAGEMENT PROCESSES IN AN ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Stefan Iovan

    2016-05-01

    Full Text Available When driving any major change within an organization, strategy and execution are intrinsic to a project’s success. Nevertheless, closing the gap between strategy and execution remains a challenge for many organizations [1]. Companies tend to focus more on execution than strategy for quick results, instead of taking the time needed to understand the parts that make up the whole, so the right execution plan can be put in place to deliver the best outcomes. A large part of this understands that business operations don’t fit neatly within the traditional organizational hierarchy. Business processes are often messy, collaborative efforts that cross teams, departments and systems, making them difficult to manage within a hierarchical structure [2]. Business process management (BPM fills this gap by redefining an organization according to its end-to-end processes, so opportunities for improvement can be identified and processes streamlined for growth, revenue and transformation. This white paper provides guidelines on what to consider when using business process applications to solve your BPM initiatives, and the unique capabilities software systems provides that can help ensure both your project’s success and the success of your organization as a whole. majority of medium and small businesses, big companies and even some guvermental organizations [2].

  8. MARTINI Model for Physisorption of Organic Molecules on Graphite

    NARCIS (Netherlands)

    Gobbo, Cristian; Beurroies, Isabelle; de Ridder, David; Eelkema, Rienk; Marrink, Siewert J.; De Feyter, Steven; van Esch, Jan H.; de Vries, Alex H.

    2013-01-01

    An extension to the MARTINI coarse-grained model is presented to describe the adsorption of organic molecules on graphite surfaces. The model allows the study of the dynamics of the preferential adsorption of long-chain organic molecules from solvent and the formation of ordered structures on the su

  9. Yeast and filamentous fungi as model organisms in microbody research

    NARCIS (Netherlands)

    Klei, Ida J. van der; Veenhuis, Marten

    2006-01-01

    Yeast and filamentous fungi are important model organisms in microbody research. The value of these organisms as models for higher eukaryotes is underscored by the observation that the principles of various aspects of microbody biology are strongly conserved from lower to higher eukaryotes. This has

  10. The initiative on Model Organism Proteomes (iMOP) Session

    DEFF Research Database (Denmark)

    Schrimpf, Sabine P; Mering, Christian von; Bendixen, Emøke

    2012-01-01

    iMOP – the Initiative on Model Organism Proteomes – was accepted as a new HUPO initiative at the Ninth HUPO meeting in Sydney in 2010. A goal of iMOP is to integrate research groups working on a great diversity of species into a model organism community. At the Tenth HUPO meeting in Geneva...

  11. Modeling the Explicit Chemistry of Anthropogenic and Biogenic Organic Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Madronich, Sasha [Univ. Corporation for Atmospheric Research, Boulder, CO (United States)

    2015-12-09

    The atmospheric burden of Secondary Organic Aerosols (SOA) remains one of the most important yet uncertain aspects of the radiative forcing of climate. This grant focused on improving our quantitative understanding of SOA formation and evolution, by developing, applying, and improving a highly detailed model of atmospheric organic chemistry, the Generation of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) model. Eleven (11) publications have resulted from this grant.

  12. Saccharomyces cerevisiae as a model organism: a comparative study.

    Directory of Open Access Journals (Sweden)

    Hiren Karathia

    Full Text Available BACKGROUND: Model organisms are used for research because they provide a framework on which to develop and optimize methods that facilitate and standardize analysis. Such organisms should be representative of the living beings for which they are to serve as proxy. However, in practice, a model organism is often selected ad hoc, and without considering its representativeness, because a systematic and rational method to include this consideration in the selection process is still lacking. METHODOLOGY/PRINCIPAL FINDINGS: In this work we propose such a method and apply it in a pilot study of strengths and limitations of Saccharomyces cerevisiae as a model organism. The method relies on the functional classification of proteins into different biological pathways and processes and on full proteome comparisons between the putative model organism and other organisms for which we would like to extrapolate results. Here we compare S. cerevisiae to 704 other organisms from various phyla. For each organism, our results identify the pathways and processes for which S. cerevisiae is predicted to be a good model to extrapolate from. We find that animals in general and Homo sapiens in particular are some of the non-fungal organisms for which S. cerevisiae is likely to be a good model in which to study a significant fraction of common biological processes. We validate our approach by correctly predicting which organisms are phenotypically more distant from S. cerevisiae with respect to several different biological processes. CONCLUSIONS/SIGNIFICANCE: The method we propose could be used to choose appropriate substitute model organisms for the study of biological processes in other species that are harder to study. For example, one could identify appropriate models to study either pathologies in humans or specific biological processes in species with a long development time, such as plants.

  13. MODEL OF LEARNING ORGANIZATION IN BROADCASTING ORGANIZATION OF ISLAMIC REPUBLIC OF IRAN

    Directory of Open Access Journals (Sweden)

    Reza Najafbagy

    2010-11-01

    Full Text Available This article tries to present a model of learning organization for Iran Broadcasting Organization which is under the management of the spiritual leader of Iran. The study is based on characteristics of Peter Senge’s original learning organization namely, personal stery, mental models, shared vision, team learning and systems thinking. The methodology was a survey research employed questionnaire among sample employees and managers of the Organization.Findings showed that the Organization is fairly far from an ffective learning organization.Moreover, it seems that employees’ performance in team learning and changes in mental models are more satisfactory than managers. Regarding other characteristics of learning organizations, there are similarities in learning attempts by employees and managers. The rganization lacks organizational vision, and consequently there is no shared vision in the Organization. It also is in need of organizational culture. As a kind of state-owned organization, there s no need of financial support which affect the need for learning organization. It also does not face the threat of sustainabilitybecause there is no competitive organization.Findings also show that IBO need a fundamental change in its rganizational learning process. In this context, the general idea is to unfreeze the mindset of leadership of IBO and creating a visionand organizational culture based on learning and staff development. Then gradually through incremental effective change and continual organizational learning process in dividual, team and organization levels engage in development and reinforcement of skills of personal mastery, mental models, shared vision, team learning and systems thinking, should lead IBO to learning organization.

  14. Integrated modelling of two xenobiotic organic compounds

    DEFF Research Database (Denmark)

    Lindblom, Erik Ulfson; Gernaey, K.V.; Henze, Mogens

    2006-01-01

    compounds, is carried out. Sorption and specific biological degradation processes are integrated with standardised water process models to model the fate of both compounds. Simulated mass flows of the two compounds during one dry weather day and one wet weather day are compared for realistic influent flow...... rate and concentration profiles. The wet weather day induces resuspension of stored sediments, which increases the pollutant load on the downstream system. The potential of the model to elucidate important phenomena related to origin and fate of the model compounds is demonstrated....

  15. Evolutionary Model to Traditional Culture and Program Organization

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-xiao; JIN Wei-xing; YANG De-qin

    2006-01-01

    To study the relationship between the evolutions of Chinese Traditional Culture (CTC) and program organization, an outline of the CTC is generalized by reviewing literature, and which is also compartmentalized into two aspects according to economic philosophy views: traditional philosophy aspect and value judgment. Based on three dimensions, which are the philosophy aspect (P), program organization model (P), and value judgment from economic philosophy views (V), and this evolution sequence, the CTC's influence on the program organization model in the evolution is discussed; then the cultural spatial evolution model for program organization based on the three dimensions (PPV) is constructed. From analyzing the plane matrix of P-P and empirical investigating on the organizational model of construction enterprises, it is found that the ancient Chinese government organizational model still has prevailing influence on the modern program organizational model in China.

  16. Mathematical models of cell self-organization

    Directory of Open Access Journals (Sweden)

    Benoît Perthame

    2011-04-01

    More recently nonlinear hyperbolic and kinetic models also have been used to describe the phenomena at a smaller scale. We explain here some motivations for ‘microscopic’ descriptions, the mathematical difficulties arising in their analysis and how kinetic models can help in understanding the unity of these descriptions.

  17. Exploring Organic Mechanistic Puzzles with Molecular Modeling

    Science.gov (United States)

    Horowitz, Gail; Schwartz, Gary

    2004-01-01

    The molecular modeling was used to reinforce more general skills such as deducing and drawing reaction mechanisms, analyzing reaction kinetics and thermodynamics and drawing reaction coordinate energy diagrams. This modeling was done through the design of mechanistic puzzles, involving reactions not familiar to the students.

  18. [Models of the organization of neonatal screening].

    Science.gov (United States)

    Cassio, A; Piazzi, S; Colli, C; Balsamo, A; Bozza, D; Salardi, S; Sprovieri, G; Cacciari, E

    1994-01-01

    The authors evaluate the different organizational strategies of a congenital hypothyroidism screening program. Positive and negative aspects of laboratory screening tests (TSH only, T4-supplemental TSH, TSH and T4), organization strategies (centralization or decentralization), recall and first follow-up criteria are examined. The authors consider that the necessity for an early diagnostic confirmation can be associated with a precise etiologic diagnosis and an evaluation of the prenatal severity of congenital hypothyroidism factors. Some European and North-American experiences are compared with the activity of a regional Italian screening center.

  19. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey; Harden, Jennifer; Maher, Kate

    2014-08-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  20. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey R.; Harden, Jennifer W.; Maher, Kate

    2014-01-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  1. Comparing risk attitudes of organic and non-organic farmers with a Bayesian random coefficient model

    NARCIS (Netherlands)

    Gardebroek, C.

    2006-01-01

    Organic farming is usually considered to be more risky than conventional farming, but the risk aversion of organic farmers compared with that of conventional farmers has not been studied. Using a non-structural approach to risk estimation, a Bayesian random coefficient model is used to obtain indivi

  2. MODEL ORGANISMS USED IN MOLECULAR BIOLOGY OR MEDICAL RESEARCH

    Directory of Open Access Journals (Sweden)

    Pandey Govind

    2011-11-01

    Full Text Available A model organism is a non-human species that is studied to understand specific biological phenomena with the expectation that investigations made in the organism model will provide insight into the workings of other organisms. The model organisms are widely used to explore potential causes and treatments for human as well as animal diseases when experiments on animals or humans would be unfeasible or considered less ethical. Studying model organisms may be informative, but care must be taken when generalizing from one organism to another. Often, model organisms are chosen on the basis that they are amenable to experimental manipulation. When researchers look for an organism to use in their studies, they look for several traits. Among these are size, generation time, accessibility, manipulation, genetics, conservation of mechanisms and potential economic benefit. As comparative molecular biology has become more common, some researchers have sought model organisms from a wider assortment of lineages on the tree of life. There are many model organisms, such as viruses (e.g., Phage lambda virus, Tobacco mosaic virus, etc., bacteria (e.g., Bacillus subtilis, Escherichia coli, Pseudomonas fluorescens, Vibrio fischeri, etc., algae (e.g., Chlamydomonas reinhardtii, Emiliania huxleyi, etc., molds (e.g., Aspergillus nidulans, Neurospora crassa, etc., yeasts (e.g., Saccharomyces cerevisiae, Ustilago maydis, etc., higher plants (e.g., Arabidopsis thaliana, Lemna gibba, Lotus japonicus, Nicotiana tabaccum, Oryza sativa, Physcomitrella patens, Zea mays, etc. and animals (e.g., Caenorhabditis elegans, guinea pig, hamster, mouse, rat, cat, chicken, dog, frog, Hydra, Drosophila melanogaster fruit fly, fish, etc..

  3. Daphnia as an Emerging Epigenetic Model Organism

    Directory of Open Access Journals (Sweden)

    Kami D. M. Harris

    2012-01-01

    Full Text Available Daphnia offer a variety of benefits for the study of epigenetics. Daphnia’s parthenogenetic life cycle allows the study of epigenetic effects in the absence of confounding genetic differences. Sex determination and sexual reproduction are epigenetically determined as are several other well-studied alternate phenotypes that arise in response to environmental stressors. Additionally, there is a large body of ecological literature available, recently complemented by the genome sequence of one species and transgenic technology. DNA methylation has been shown to be altered in response to toxicants and heavy metals, although investigation of other epigenetic mechanisms is only beginning. More thorough studies on DNA methylation as well as investigation of histone modifications and RNAi in sex determination and predator-induced defenses using this ecologically and evolutionarily important organism will contribute to our understanding of epigenetics.

  4. MODELLING CONSUMERS' DEMAND FOR ORGANIC FOOD PRODUCTS: THE SWEDISH EXPERIENCE

    OpenAIRE

    Manuchehr Irandoust

    2016-01-01

    This paper attempts to examine a few factors characterizing consumer preferences and behavior towards organic food products in the south of Sweden using a proportional odds model which captures the natural ordering of dependent variables and any inherent nonlinearities. The findings show that consumer's choice for organic food depends on perceived benefits of organic food (environment, health, and quality) and consumer's perception and attitudes towards labelling system, message framing, and ...

  5. Organic production in a dynamic CGE model

    DEFF Research Database (Denmark)

    Jacobsen, Lars Bo

    2004-01-01

    accumulation relationship for land, and an explicit modeling of the rate of stock accumulation (i.e., of land investment). We assume that land is industry specific, with land rentals adjusting to ensure that land supply equals land demand for each industry. Once the decision has been made to transform land...

  6. Nematodes: Model Organisms in High School Biology

    Science.gov (United States)

    Bliss, TJ; Anderson, Margery; Dillman, Adler; Yourick, Debra; Jett, Marti; Adams, Byron J.; Russell, RevaBeth

    2007-01-01

    In a collaborative effort between university researchers and high school science teachers, an inquiry-based laboratory module was designed using two species of insecticidal nematodes to help students apply scientific inquiry and elements of thoughtful experimental design. The learning experience and model are described in this article. (Contains 4…

  7. Representational Translation with Concrete Models in Organic Chemistry

    Science.gov (United States)

    Stull, Andrew T.; Hegarty, Mary; Dixon, Bonnie; Stieff, Mike

    2012-01-01

    In representation-rich domains such as organic chemistry, students must be facile and accurate when translating between different 2D representations, such as diagrams. We hypothesized that translating between organic chemistry diagrams would be more accurate when concrete models were used because difficult mental processes could be augmented by…

  8. Investigating ecological speciation in non-model organisms

    DEFF Research Database (Denmark)

    Foote, Andrew David

    2012-01-01

    Background: Studies of ecological speciation tend to focus on a few model biological systems. In contrast, few studies on non-model organisms have been able to infer ecological speciation as the underlying mechanism of evolutionary divergence. Questions: What are the pitfalls in studying ecological...... speciation in non-model organisms that lead to this bias? What alternative approaches might redress the balance? Organism: Genetically differentiated types of the killer whale (Orcinus orca) exhibiting differences in prey preference, habitat use, morphology, and behaviour. Methods: Review of the literature...... variation underlie reproductive isolation between sympatric killer whale types. Perhaps ecological speciation has occurred, but it is hard to prove. We will probably face this outcome whenever we wish to address non-model organisms – species in which it is not easy to apply experimental approaches...

  9. Self-organizing map models of language acquisition

    Science.gov (United States)

    Li, Ping; Zhao, Xiaowei

    2013-01-01

    Connectionist models have had a profound impact on theories of language. While most early models were inspired by the classic parallel distributed processing architecture, recent models of language have explored various other types of models, including self-organizing models for language acquisition. In this paper, we aim at providing a review of the latter type of models, and highlight a number of simulation experiments that we have conducted based on these models. We show that self-organizing connectionist models can provide significant insights into long-standing debates in both monolingual and bilingual language development. We suggest future directions in which these models can be extended, to better connect with behavioral and neural data, and to make clear predictions in testing relevant psycholinguistic theories. PMID:24312061

  10. Self-organizing map models of language acquisition.

    Science.gov (United States)

    Li, Ping; Zhao, Xiaowei

    2013-11-19

    Connectionist models have had a profound impact on theories of language. While most early models were inspired by the classic parallel distributed processing architecture, recent models of language have explored various other types of models, including self-organizing models for language acquisition. In this paper, we aim at providing a review of the latter type of models, and highlight a number of simulation experiments that we have conducted based on these models. We show that self-organizing connectionist models can provide significant insights into long-standing debates in both monolingual and bilingual language development. We suggest future directions in which these models can be extended, to better connect with behavioral and neural data, and to make clear predictions in testing relevant psycholinguistic theories.

  11. Labour Quality Model for Organic Farming Food Chains

    OpenAIRE

    Gassner, B.; Freyer, B.; Leitner, H.

    2008-01-01

    The debate on labour quality in science is controversial as well as in the organic agriculture community. Therefore, we reviewed literature on different labour quality models and definitions, and had key informant interviews on labour quality issues with stakeholders in a regional oriented organic agriculture bread food chain. We developed a labour quality model with nine quality categories and discussed linkages to labour satisfaction, ethical values and IFOAM principles.

  12. Kineic Modelling of Degradation of Organic Compounds in Soils

    Institute of Scientific and Technical Information of China (English)

    WANGZONGSHENG; ZHANGSHUIMING; 等

    1997-01-01

    A set of equations in suggested to describe the kinetics of degradation of organic ompounds applied to soils ad the kinetics of growth of the inolved microorganisms:-dx/dt=jx+kxm dm/dt=-fm+gxm where x is the concentration of organic compound at time t,m is the numer of microorganisms capable of degrading the organic compound at time t,while j,k,f and g are positive constants,This model can satisfactorily be used to explain the degradation curve of organic compounds and the growth curve of the involved microorganisms.

  13. BUSINESS PROCESS MODELLING FOR PROJECTS COSTS MANAGEMENT IN AN ORGANIZATION

    Directory of Open Access Journals (Sweden)

    PĂTRAŞCU AURELIA

    2014-05-01

    Full Text Available Using Information Technologies in organizations represents an evident progress for company, money economy, time economy and generates value for the organization. In this paper the author proposes to model the business processes for an organization that manages projects costs, because modelling is an important part of any software development process. Using software for projects costs management is essential because it allows the management of all operations according to the established parameters, the management of the projects groups, as well as the management of the projects and subprojects, at different complexity levels.

  14. Mathematical model for cyclodextrin alteration of bioavailability of organic pollutants.

    Science.gov (United States)

    Liu, Huihui; Cai, Xiyun; Chen, Jingwen

    2013-06-04

    While many cyclodextrin-based applications have been developed to assess or enhance bioavailability of organic pollutants, the choice of cyclodextrin (CD) is largely empirical, with little consideration of pollutant diversity and environmental matrix effects. This study aimed at developing a mathematical model for quantifying CD alteration of bioavailability of organic pollutants. Cyclodextrin appears to have multiple effects, together contributing to its bioavailability-enhancing property. Cyclodextrin is adsorbed onto the adsorbent matrix to different extents. The adsorbed CD is capable of sequestrating organic pollutants, highlighting the role of a pseudophase similar to solid environmental matrix. Aqueous CD can reduce adsorption of organic pollutants via inclusion complexation. The two effects cancel each other to a certain degree, which determines the levels of organic pollutants dissolved (comprising freely dissolved and CD-included forms). Additionally, the CD-included form is nearly identical in biological activity to the free form. A mathematical model of one variable (i.e., CD concentration) was derived to quantify effects of CD on the bioavailability of organic pollutants. Model analysis indicates that alteration of bioavailability of organic pollutants by CD depends on both CD (type and level) and environmental matrix. The selection of CD type and amendment level for a given application may be predicted by the model.

  15. A survey of financial planning models for health care organizations.

    Science.gov (United States)

    Coleman, J R; Kaminsky, F C; McGee, F

    1978-01-01

    This paper describes "what if?" financial planning models developed for health care administrators and financial managers to study and evaluate the economic impact of changes in a health care organization's charge structure, operating policies, reimbursement plans, and services and resources. Models for inpatient and outpatient care systems are presented. The models are described in terms of input, output, and application. An assessment of the state of the art of financial planning and prospects for the future of what if?models are given.

  16. Drosophila melanogaster as a model organism to study nanotoxicity.

    Science.gov (United States)

    Ong, Cynthia; Yung, Lin-Yue Lanry; Cai, Yu; Bay, Boon-Huat; Baeg, Gyeong-Hun

    2015-05-01

    Drosophila melanogaster has been used as an in vivo model organism for the study of genetics and development since 100 years ago. Recently, the fruit fly Drosophila was also developed as an in vivo model organism for toxicology studies, in particular, the field of nanotoxicity. The incorporation of nanomaterials into consumer and biomedical products is a cause for concern as nanomaterials are often associated with toxicity in many in vitro studies. In vivo animal studies of the toxicity of nanomaterials with rodents and other mammals are, however, limited due to high operational cost and ethical objections. Hence, Drosophila, a genetically tractable organism with distinct developmental stages and short life cycle, serves as an ideal organism to study nanomaterial-mediated toxicity. This review discusses the basic biology of Drosophila, the toxicity of nanomaterials, as well as how the Drosophila model can be used to study the toxicity of various types of nanomaterials.

  17. Phytoremediation and its models for organic contaminated soils

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Soil pollution has been attracting considerable public attentions over the last decades. Sorts of traditional physiochemical methods have been used to remove the organic pollutants from soils. However, the enormous costs and low efficiencies associated with these remediation technologies limit their availabilities. Phytoremediation is an emerging technology that uses plants to cleanup pollutants in soils. As overwhelmingly positive results have been shown, phytoremediation is a most economical and effective remediation technique for organic contaminated soils. In this paper phytoremediation and its models for organic contaminated soils is overviewed. The mechanisms of phytoremediation mainly include the direct plant uptake of organic pollutants, degradation by plant-derived degradative enzymes, and stimulated biodegradation in plant rhizosphere. Phytoremediation efficiency is tightly related to physicochemical properties of organic pollutants, environmental characteristics, and plant types. It is no doubt that soil amendments such as surfactants change the solubilities and availabilities of organic pollutants in soils. However, little information is available about effects of soil amendments on phytoremediation efficiencies. Phytoremediation models have been developed to simulate and predict the environmental behavior of organic pollutants, and progress of models is illustrated. In many ways phytoremediation is still in its initial stage, and recommendations for the future research on phytoremediation are presented.

  18. Modeling secondary organic aerosol formation through cloud processing of organic compounds

    Directory of Open Access Journals (Sweden)

    J. Chen

    2007-06-01

    Full Text Available Interest in the potential formation of secondary organic aerosol (SOA through reactions of organic compounds in condensed aqueous phases is growing. In this study, the potential formation of SOA from irreversible aqueous-phase reactions of organic species in clouds was investigated. A new proposed aqueous-phase chemistry mechanism (AqChem is coupled with the existing gas-phase Caltech Atmospheric Chemistry Mechanism (CACM and the Model to Predict the Multiphase Partitioning of Organics (MPMPO that simulate SOA formation. AqChem treats irreversible organic reactions that lead mainly to the formation of carboxylic acids, which are usually less volatile than the corresponding aldehydic compounds. Zero-dimensional model simulations were performed for tropospheric conditions with clouds present for three consecutive hours per day. Zero-dimensional model simulations show that 48-h averaged SOA formation are increased by 27% for a rural scenario with strong monoterpene emissions and 7% for an urban scenario with strong emissions of aromatic compounds, respectively, when irreversible organic reactions in clouds are considered. AqChem was also incorporated into the Community Multiscale Air Quality Model (CMAQ version 4.4 with CACM/MPMPO and applied to a previously studied photochemical episode (3–4 August 2004 focusing on the eastern United States. The CMAQ study indicates that the maximum contribution of SOA formation from irreversible reactions of organics in clouds is 0.28 μg m−3 for 24-h average concentrations and 0.60 μg m−3 for one-hour average concentrations at certain locations. On average, domain-wide surface SOA predictions for the episode are increased by 8.6% when irreversible, in-cloud processing of organics is considered.

  19. A Workforce Design Model: Providing Energy to Organizations in Transition

    Science.gov (United States)

    Halm, Barry J.

    2011-01-01

    The purpose of this qualitative study was to examine the change in performance realized by a professional services organization, which resulted in the Life Giving Workforce Design (LGWD) model through a grounded theory research design. This study produced a workforce design model characterized as an organizational blueprint that provides virtuous…

  20. Simple model of self-organized biological evolution

    Science.gov (United States)

    de Boer, Jan; Derrida, Bernard; Flyvbjerg, Henrik; Jackson, Andrew D.; Wettig, Tilo

    1994-08-01

    We give an exact solution of a recently proposed self-organized critical model of biological evolution. We show that the model has a power law distribution of durations of coevolutionary ``avalanches'' with a mean field exponent 3/2. We also calculate analytically the finite size effects which cut off this power law at times of the order of the system size.

  1. Modeling organic compounds in the estuarine and coastal environment

    NARCIS (Netherlands)

    R.W.P.M. Laane; D. van de Meent; P. de Voogt; J. Parsons; J. Hendriks; J. van Gils

    2011-01-01

    This chapter describes the historical development and present applications of water-quality models for organic chemical compounds (e.g., polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)). Various types of water-quality models are described, varying in the amount of compar

  2. Fruit tree model for uptake of organic compounds from soil

    DEFF Research Database (Denmark)

    Trapp, Stefan; Rasmussen, D.; Samsoe-Petersen, L.

    2003-01-01

    soils, regressions or models are in use, which were not intended to be used for tree fruits. A simple model for uptake of neutral organic contaminants into fruits is developed. It considers xylem and phloem transport to fruits through the stem. The mass balance is solved for the steady...

  3. Towards an Intelligent Project Based Organization Business Model

    Directory of Open Access Journals (Sweden)

    Alami Marrouni Oussama

    2013-01-01

    Full Text Available Global economy is undergoing a recession phase that had made competition tougher and imposed new business framework. Businesses have to shift from the classical management approaches to an Intelligent Project Based Organization (IPBO model that provides flexibility and agility. IPBO model is intended to reinforce the proven advantages of Project Based Organization (PBO by the use of suitable Enterprise Intelligence (EI Systems. The goal of this paper is to propose an IPBO model that combines benefits of PBO and EI and helps overcoming their pitfalls

  4. Xanthusbase: adapting wikipedia principles to a model organism database.

    Science.gov (United States)

    Arshinoff, Bradley I; Suen, Garret; Just, Eric M; Merchant, Sohel M; Kibbe, Warren A; Chisholm, Rex L; Welch, Roy D

    2007-01-01

    xanthusBase (http://www.xanthusbase.org) is the official model organism database (MOD) for the social bacterium Myxococcus xanthus. In many respects, M.xanthus represents the pioneer model organism (MO) for studying the genetic, biochemical, and mechanistic basis of prokaryotic multicellularity, a topic that has garnered considerable attention due to the significance of biofilms in both basic and applied microbiology research. To facilitate its utility, the design of xanthusBase incorporates open-source software, leveraging the cumulative experience made available through the Generic Model Organism Database (GMOD) project, MediaWiki (http://www.mediawiki.org), and dictyBase (http://www.dictybase.org), to create a MOD that is both highly useful and easily navigable. In addition, we have incorporated a unique Wikipedia-style curation model which exploits the internet's inherent interactivity, thus enabling M.xanthus and other myxobacterial researchers to contribute directly toward the ongoing genome annotation.

  5. An Ising model for metal-organic frameworks

    Science.gov (United States)

    Höft, Nicolas; Horbach, Jürgen; Martín-Mayor, Victor; Seoane, Beatriz

    2017-08-01

    We present a three-dimensional Ising model where lines of equal spins are frozen such that they form an ordered framework structure. The frame spins impose an external field on the rest of the spins (active spins). We demonstrate that this "porous Ising model" can be seen as a minimal model for condensation transitions of gas molecules in metal-organic frameworks. Using Monte Carlo simulation techniques, we compare the phase behavior of a porous Ising model with that of a particle-based model for the condensation of methane (CH4) in the isoreticular metal-organic framework IRMOF-16. For both models, we find a line of first-order phase transitions that end in a critical point. We show that the critical behavior in both cases belongs to the 3D Ising universality class, in contrast to other phase transitions in confinement such as capillary condensation.

  6. The expanding epigenetic landscape of non-model organisms.

    Science.gov (United States)

    Bonasio, Roberto

    2015-01-01

    Epigenetics studies the emergence of different phenotypes from a single genotype. Although these processes are essential to cellular differentiation and transcriptional memory, they are also widely used in all branches of the tree of life by organisms that require plastic but stable adaptation to their physical and social environment. Because of the inherent flexibility of epigenetic regulation, a variety of biological phenomena can be traced back to evolutionary adaptations of few conserved molecular pathways that converge on chromatin. For these reasons chromatin biology and epigenetic research have a rich history of chasing discoveries in a variety of model organisms, including yeast, flies, plants and humans. Many more fascinating examples of epigenetic plasticity lie outside the realm of model organisms and have so far been only sporadically investigated at a molecular level; however, recent progress on sequencing technology and genome editing tools have begun to blur the lines between model and non-model organisms, opening numerous new avenues for investigation. Here, I review examples of epigenetic phenomena in non-model organisms that have emerged as potential experimental systems, including social insects, fish and flatworms, and are becoming accessible to molecular approaches.

  7. Regional Persistent Organic Pollutants' Environmental Impact Assessment and Control Model

    Directory of Open Access Journals (Sweden)

    Jurgis Staniskis

    2008-10-01

    Full Text Available The sources of formation, environmental distribution and fate of persistent organic pollutants (POPs are increasingly seen as topics to be addressed and solved at the global scale. Therefore, there are already two international agreements concerning persistent organic pollutants: the Protocol of 1998 to the 1979 Convention on the Long-Range Transboundary Air Pollution on Persistent Organic Pollutants (Aarhus Protocol; and the Stockholm Convention on Persistent Organic Pollutants. For the assessment of environmental pollution of POPs, for the risk assessment, for the evaluation of new pollutants as potential candidates to be included in the POPs list of the Stokholmo or/and Aarhus Protocol, a set of different models are developed or under development. Multimedia models help describe and understand environmental processes leading to global contamination through POPs and actual risk to the environment and human health. However, there is a lack of the tools based on a systematic and integrated approach to POPs management difficulties in the region.

  8. Quantitative model studies for interfaces in organic electronic devices

    Science.gov (United States)

    Gottfried, J. Michael

    2016-11-01

    In organic light-emitting diodes and similar devices, organic semiconductors are typically contacted by metal electrodes. Because the resulting metal/organic interfaces have a large impact on the performance of these devices, their quantitative understanding is indispensable for the further rational development of organic electronics. A study by Kröger et al (2016 New J. Phys. 18 113022) of an important single-crystal based model interface provides detailed insight into its geometric and electronic structure and delivers valuable benchmark data for computational studies. In view of the differences between typical surface-science model systems and real devices, a ‘materials gap’ is identified that needs to be addressed by future research to make the knowledge obtained from fundamental studies even more beneficial for real-world applications.

  9. MODELLING CONSUMERS' DEMAND FOR ORGANIC FOOD PRODUCTS: THE SWEDISH EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Manuchehr Irandoust

    2016-07-01

    Full Text Available This paper attempts to examine a few factors characterizing consumer preferences and behavior towards organic food products in the south of Sweden using a proportional odds model which captures the natural ordering of dependent variables and any inherent nonlinearities. The findings show that consumer's choice for organic food depends on perceived benefits of organic food (environment, health, and quality and consumer's perception and attitudes towards labelling system, message framing, and local origin. In addition, high willingness to pay and income level will increase the probability to buy organic food, while the cultural differences and socio-demographic characteristics have no effect on consumer behaviour and attitudes towards organic food products. Policy implications are offered.

  10. Lotka-Volterra competition models for sessile organisms.

    Science.gov (United States)

    Spencer, Matthew; Tanner, Jason E

    2008-04-01

    Markov models are widely used to describe the dynamics of communities of sessile organisms, because they are easily fitted to field data and provide a rich set of analytical tools. In typical ecological applications, at any point in time, each point in space is in one of a finite set of states (e.g., species, empty space). The models aim to describe the probabilities of transitions between states. In most Markov models for communities, these transition probabilities are assumed to be independent of state abundances. This assumption is often suspected to be false and is rarely justified explicitly. Here, we start with simple assumptions about the interactions among sessile organisms and derive a model in which transition probabilities depend on the abundance of destination states. This model is formulated in continuous time and is equivalent to a Lotka-Volterra competition model. We fit this model and a variety of alternatives in which transition probabilities do not depend on state abundances to a long-term coral reef data set. The Lotka-Volterra model describes the data much better than all models we consider other than a saturated model (a model with a separate parameter for each transition at each time interval, which by definition fits the data perfectly). Our approach provides a basis for further development of stochastic models of sessile communities, and many of the methods we use are relevant to other types of community. We discuss possible extensions to spatially explicit models.

  11. Modeling nanostructure-enhanced light trapping in organic solar cells

    DEFF Research Database (Denmark)

    Adam, Jost

    A promising approach for improving the power conversion efficiencies of organic solar cells (OSCs) is by incorporating nanostructures in their thin film architecture to improve the light absorption in the device’s active polymer layers. Here, we present a modelling framework for the prediction....... Diffraction by fractal metallic supergratings. Optics Express, 15(24), 15628–15636 (2007) [3] Goszczak, A. J. et al. Nanoscale Aluminum dimples for light trapping in organic thin films (submitted)...

  12. Modelling the formation of organic particles in the atmosphere

    Science.gov (United States)

    Anttila, T.; Kerminen, V.-M.; Kulmala, M.; Laaksonen, A.; O'Dowd, C.

    2003-12-01

    A modelling study investigating the formation of organic particles from inorganic, thermodynamically stable clusters was carried out. A recently-developed theory, the so-called nano-Köhler theory, which describes a thermodynamic equilibrium between a nanometer-size cluster, water and water-soluble organic compound, was implemented in a dynamical model along with a treatment of the appropriate aerosol and gas-phase processes. The obtained results suggest that both gaseous sulphuric acid and organic vapours contribute to organic particle formation. The initial growth of freshly-nucleated clusters having a diameter around 1 nm is driven by condensation of gaseous sulphuric acid and by a lesser extent cluster self-coagulation. After the clusters have reached sizes of around 2 nm in diameter, low-volatile organic vapours start to condense spontaneously into the clusters, thereby accelerating their growth to detectable sizes. A shortage of gaseous sulphuric acid or organic vapours limit, or suppress altogether, the particle formation, since freshly-nucleated clusters are rapidly coagulated away by pre-existing particles. The obtained modelling results were applied to explaining the observed seasonal cycle in the number of aerosol formation events in a continental forest site.

  13. Precisely parameterized experimental and computational models of tissue organization.

    Science.gov (United States)

    Molitoris, Jared M; Paliwal, Saurabh; Sekar, Rajesh B; Blake, Robert; Park, JinSeok; Trayanova, Natalia A; Tung, Leslie; Levchenko, Andre

    2016-02-01

    Patterns of cellular organization in diverse tissues frequently display a complex geometry and topology tightly related to the tissue function. Progressive disorganization of tissue morphology can lead to pathologic remodeling, necessitating the development of experimental and theoretical methods of analysis of the tolerance of normal tissue function to structural alterations. A systematic way to investigate the relationship of diverse cell organization to tissue function is to engineer two-dimensional cell monolayers replicating key aspects of the in vivo tissue architecture. However, it is still not clear how this can be accomplished on a tissue level scale in a parameterized fashion, allowing for a mathematically precise definition of the model tissue organization and properties down to a cellular scale with a parameter dependent gradual change in model tissue organization. Here, we describe and use a method of designing precisely parameterized, geometrically complex patterns that are then used to control cell alignment and communication of model tissues. We demonstrate direct application of this method to guiding the growth of cardiac cell cultures and developing mathematical models of cell function that correspond to the underlying experimental patterns. Several anisotropic patterned cultures spanning a broad range of multicellular organization, mimicking the cardiac tissue organization of different regions of the heart, were found to be similar to each other and to isotropic cell monolayers in terms of local cell-cell interactions, reflected in similar confluency, morphology and connexin-43 expression. However, in agreement with the model predictions, different anisotropic patterns of cell organization, paralleling in vivo alterations of cardiac tissue morphology, resulted in variable and novel functional responses with important implications for the initiation and maintenance of cardiac arrhythmias. We conclude that variations of tissue geometry and topology

  14. Modeling of Spatially Correlated Energetic Disorder in Organic Semiconductors.

    Science.gov (United States)

    Kordt, Pascal; Andrienko, Denis

    2016-01-12

    Mesoscale modeling of organic semiconductors relies on solving an appropriately parametrized master equation. Essential ingredients of the parametrization are site energies (driving forces), which enter the charge transfer rate between pairs of neighboring molecules. Site energies are often Gaussian-distributed and are spatially correlated. Here, we propose an algorithm that generates these energies with a given Gaussian distribution and spatial correlation function. The method is tested on an amorphous organic semiconductor, DPBIC, illustrating that the accurate description of correlations is essential for the quantitative modeling of charge transport in amorphous mesophases.

  15. Biobanking of a Marine Invertebrate Model Organism: The Sea Urchin

    Directory of Open Access Journals (Sweden)

    Estefania Paredes

    2016-01-01

    Full Text Available The sea urchin has long been used as an invertebrate model organism in developmental biology, membrane transport and sperm oocyte interactions, and for the assessment of marine pollution. This review explores the effects of cryopreservation and biobanking in the biology and development of sea urchins, all the way from germaplasm through to juveniles. This review will provide an integral view of the process and all that is known so far about the biology of cryopreserved sea urchins, as well as provide an insight on the applications of the biobanking of these model organisms.

  16. The effect of hair bundle shape on hair bundle hydrodynamics of non-mammalian inner ear hair cells for the full frequency range.

    Science.gov (United States)

    Shatz, Lisa F

    2004-09-01

    The effect of the size and the shape of the hair bundle of a hair cell in the inner ear of non-mammals on its motion for the full range of frequencies is determined thereby extending the results of a previous analysis of hair bundle motion for high and low frequencies [Hear Res. 141 (2000) 39-50]. A hemispheroid is used to represent the hair bundle because it can represent a full range of shapes, from thin, pencil-like shapes to wide, flat, disk-like shapes. Boundary element methods are used to approximate the solution for the hydrodynamics. For physiologically relevant parameters, an excellent match is obtained between the model's predictions and measurements of hair bundle motion in the free-standing region of the basilar papilla of the alligator lizard [Aranyosi, Measuring sound-induced motions of the alligator lizard cochlea. Massachusetts Institute of Technology, PhD Thesis, 2002]. Neither in the model's predictions nor in experimental measurements is sharp tuning observed. The model predicted the low frequency region of neural tuning curves for the alligator lizard and bobtail lizard, but could not predict the sharp tuning or the high frequency region. An element that represents an active mechanism is added to the hair bundle model to predict neural tuning curves, which are sharply tuned, and an excellent match is obtained for all the characteristics of neural tuning curves for the alligator lizard, and for the low and high frequency regions for the bobtail lizard. The model does not predict well the sharp tuning of the shorter hair bundles of the bobtail lizard, possibly because it does not represent tectorial sallets.

  17. Workshop meeting report Organs-on-Chips: human disease models.

    Science.gov (United States)

    van de Stolpe, Anja; den Toonder, Jaap

    2013-09-21

    The concept of "Organs-on-Chips" has recently evolved and has been described as 3D (mini-) organs or tissues consisting of multiple and different cell types interacting with each other under closely controlled conditions, grown in a microfluidic chip, and mimicking the complex structures and cellular interactions in and between different cell types and organs in vivo, enabling the real time monitoring of cellular processes. In combination with the emerging iPSC (induced pluripotent stem cell) field this development offers unprecedented opportunities to develop human in vitro models for healthy and diseased organ tissues, enabling the investigation of fundamental mechanisms in disease development, drug toxicity screening, drug target discovery and drug development, and the replacement of animal testing. Capturing the genetic background of the iPSC donor in the organ or disease model carries the promise to move towards "in vitro clinical trials", reducing costs for drug development and furthering the concept of personalized medicine and companion diagnostics. During the Lorentz workshop (Leiden, September 2012) an international multidisciplinary group of experts discussed the current state of the art, available and emerging technologies, applications and how to proceed in the field. Organ-on-a-chip platform technologies are expected to revolutionize cell biology in general and drug development in particular.

  18. Stochastic models for plant microtubule self-organization and structure.

    Science.gov (United States)

    Eren, Ezgi C; Dixit, Ram; Gautam, Natarajan

    2015-12-01

    One of the key enablers of shape and growth in plant cells is the cortical microtubule (CMT) system, which is a polymer array that forms an appropriately-structured scaffolding in each cell. Plant biologists have shown that stochastic dynamics and simple rules of interactions between CMTs can lead to a coaligned CMT array structure. However, the mechanisms and conditions that cause CMT arrays to become organized are not well understood. It is prohibitively time-consuming to use actual plants to study the effect of various genetic mutations and environmental conditions on CMT self-organization. In fact, even computer simulations with multiple replications are not fast enough due to the spatio-temporal complexity of the system. To redress this shortcoming, we develop analytical models and methods for expeditiously computing CMT system metrics that are related to self-organization and array structure. In particular, we formulate a mean-field model to derive sufficient conditions for the organization to occur. We show that growth-prone dynamics itself is sufficient to lead to organization in presence of interactions in the system. In addition, for such systems, we develop predictive methods for estimation of system metrics such as expected average length and number of CMTs over time, using a stochastic fluid-flow model, transient analysis, and approximation algorithms tailored to our problem. We illustrate the effectiveness of our approach through numerical test instances and discuss biological insights.

  19. Implementing Marine Organic Aerosols Into the GEOS-Chem Model

    Science.gov (United States)

    Johnson, Matthew S.

    2015-01-01

    Marine-sourced organic aerosols (MOA) have been shown to play an important role in tropospheric chemistry by impacting surface mass, cloud condensation nuclei, and ice nuclei concentrations over remote marine and coastal regions. In this work, an online marine primary organic aerosol emission parameterization, designed to be used for both global and regional models, was implemented into the GEOS-Chem model. The implemented emission scheme improved the large under-prediction of organic aerosol concentrations in clean marine regions (normalized mean bias decreases from -79% when using the default settings to -12% when marine organic aerosols are added). Model predictions were also in good agreement (correlation coefficient of 0.62 and normalized mean bias of -36%) with hourly surface concentrations of MOA observed during the summertime at an inland site near Paris, France. Our study shows that MOA have weaker coastal-to-inland concentration gradients than sea-salt aerosols, leading to several inland European cities having > 10% of their surface submicron organic aerosol mass concentration with a marine source. The addition of MOA tracers to GEOS-Chem enabled us to identify the regions with large contributions of freshly-emitted or aged aerosol having distinct physicochemical properties, potentially indicating optimal locations for future field studies.

  20. Self-organized Criticality Model for Ocean Internal Waves

    Institute of Scientific and Technical Information of China (English)

    WANG Gang; LIN Min; QIAO Fang-Li; HOU Yi-Jun

    2009-01-01

    In this paper, we present a simple spring-block model for ocean internal waves based on the self-organized criticality (SOC). The oscillations of the water blocks in the model display power-law behavior with an exponent of-2 in the frequency domain, which is similar to the current and sea water temperature spectra in the actual ocean and the universal Garrett and Munk deep ocean internal wave model [Geophysical Fluid Dynamics 2 (1972) 225; J. Geophys. Res. 80 (1975) 291]. The influence of the ratio of the driving force to the spring coefficient to SOC behaviors in the model is also discussed.

  1. Financial market model based on self-organized percolation

    Institute of Scientific and Technical Information of China (English)

    YANG Chunxia; WANG Jie; ZHOU Tao; LIU Jun; XU Min; ZHOU Peiling; WANG Binghong

    2005-01-01

    Starting with the self-organized evolution of the trader group's structure, a parsimonious percolation model for stock market is established, which can be considered as a kind of betterment of the Cont-Bouchaud model. The return distribution of the present model obeys Lévy form in the center and displays fat-tail property, in accord with the stylized facts observed in real-life financial time series. Furthermore, this model reveals the power-law relationship between the peak value of the probability distribution and the time scales, in agreement with the empirical studies on the Hang Seng Index.

  2. Green Algae as Model Organisms for Biological Fluid Dynamics.

    Science.gov (United States)

    Goldstein, Raymond E

    2015-01-01

    In the past decade the volvocine green algae, spanning from the unicellular Chlamydomonas to multicellular Volvox, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 μm to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.

  3. There Is No Simple Model of the Plasma Membrane Organization

    Science.gov (United States)

    Bernardino de la Serna, Jorge; Schütz, Gerhard J.; Eggeling, Christian; Cebecauer, Marek

    2016-01-01

    Ever since technologies enabled the characterization of eukaryotic plasma membranes, heterogeneities in the distributions of its constituents were observed. Over the years this led to the proposal of various models describing the plasma membrane organization such as lipid shells, picket-and-fences, lipid rafts, or protein islands, as addressed in numerous publications and reviews. Instead of emphasizing on one model we in this review give a brief overview over current models and highlight how current experimental work in one or the other way do not support the existence of a single overarching model. Instead, we highlight the vast variety of membrane properties and components, their influences and impacts. We believe that highlighting such controversial discoveries will stimulate unbiased research on plasma membrane organization and functionality, leading to a better understanding of this essential cellular structure. PMID:27747212

  4. Review of existing terrestrial bioaccumulation models and terrestrial bioaccumulation modeling needs for organic chemicals

    Science.gov (United States)

    Protocols for terrestrial bioaccumulation assessments are far less-developed than for aquatic systems. This manuscript reviews modeling approaches that can be used to assess the terrestrial bioaccumulation potential of commercial organic chemicals. Models exist for plant, inver...

  5. A dynamical phyllotaxis model to determine floral organ number.

    Directory of Open Access Journals (Sweden)

    Miho S Kitazawa

    2015-05-01

    Full Text Available How organisms determine particular organ numbers is a fundamental key to the development of precise body structures; however, the developmental mechanisms underlying organ-number determination are unclear. In many eudicot plants, the primordia of sepals and petals (the floral organs first arise sequentially at the edge of a circular, undifferentiated region called the floral meristem, and later transition into a concentric arrangement called a whorl, which includes four or five organs. The properties controlling the transition to whorls comprising particular numbers of organs is little explored. We propose a development-based model of floral organ-number determination, improving upon earlier models of plant phyllotaxis that assumed two developmental processes: the sequential initiation of primordia in the least crowded space around the meristem and the constant growth of the tip of the stem. By introducing mutual repulsion among primordia into the growth process, we numerically and analytically show that the whorled arrangement emerges spontaneously from the sequential initiation of primordia. Moreover, by allowing the strength of the inhibition exerted by each primordium to decrease as the primordium ages, we show that pentamerous whorls, in which the angular and radial positions of the primordia are consistent with those observed in sepal and petal primordia in Silene coeli-rosa, Caryophyllaceae, become the dominant arrangement. The organ number within the outmost whorl, corresponding to the sepals, takes a value of four or five in a much wider parameter space than that in which it takes a value of six or seven. These results suggest that mutual repulsion among primordia during growth and a temporal decrease in the strength of the inhibition during initiation are required for the development of the tetramerous and pentamerous whorls common in eudicots.

  6. Modeling organic matter stabilization during windrow composting of livestock effluents.

    Science.gov (United States)

    Oudart, D; Paul, E; Robin, P; Paillat, J M

    2012-01-01

    Composting is a complex bioprocess, requiring a lot of empirical experiments to optimize the process. A dynamical mathematical model for the biodegradation of the organic matter during the composting process has been developed. The initial organic matter expressed by chemical oxygen demand (COD) is decomposed into rapidly and slowly degraded compartments and an inert one. The biodegradable COD is hydrolysed and consumed by microorganisms and produces metabolic water and carbon dioxide. This model links a biochemical characterization of the organic matter by Van Soest fractionating with COD. The comparison of experimental and simulation results for carbon dioxide emission, dry matter and carbon content balance showed good correlation. The initial sizes of the biodegradable COD compartments are explained by the soluble, hemicellulose-like and lignin fraction. Their sizes influence the amplitude of the carbon dioxide emission peak. The initial biomass is a sensitive variable too, influencing the time at which the emission peak occurs.

  7. Simple model of self-organized biological evolution

    Energy Technology Data Exchange (ETDEWEB)

    de Boer, J.; Derrida, B.; Flyvbjerg, H.; Jackson, A.D.; Wettig, T. (Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States) The Isaac Newton Institute for Mathematical Sciences, 20 Clarkson Road, Cambridge, CB4 0EH (United Kingdom) Laboratoire de Physique Statistique, Ecole Normale Superieure, 24 rue Lhomond, F-75005 Paris (France) Service de Physique Theorique, Centre de Etudes Nucleaires de Saclay, F-91191, Gif-Sur-Yvette (France) CONNECT, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark))

    1994-08-08

    We give an exact solution of a recently proposed self-organized critical model of biological evolution. We show that the model has a power law distribution of durations of coevolutionary avalanches'' with a mean field exponent 3/2. We also calculate analytically the finite size effects which cut off this power law at times of the order of the system size.

  8. BeetleBase: the model organism database for Tribolium castaneum

    OpenAIRE

    Wang, Liangjiang; Wang, Suzhi; Li, Yonghua; Paradesi, Martin S. R.; Brown, Susan J

    2006-01-01

    BeetleBase () is an integrated resource for the Tribolium research community. The red flour beetle (Tribolium castaneum) is an important model organism for genetics, developmental biology, toxicology and comparative genomics, the genome of which has recently been sequenced. BeetleBase is constructed to integrate the genomic sequence data with information about genes, mutants, genetic markers, expressed sequence tags and publications. BeetleBase uses the Chado data model and software component...

  9. A two-site bipolaron model for organic magnetoresistance

    Science.gov (United States)

    Wagemans, W.; Bloom, F. L.; Bobbert, P. A.; Wohlgenannt, M.; Koopmans, B.

    2008-04-01

    The recently proposed bipolaron model for large "organic magnetoresistance" (OMAR) at room temperature is extended to an analytically solvable two-site scheme. It is shown that even this extremely simplified approach reproduces some of the key features of OMAR, viz., the possibility to have both positive and negative magnetoresistance, as well as its universal line shapes. Specific behavior and limiting cases are discussed. Extensions of the model, to guide future experiments and numerical Monte Carlo studies, are suggested.

  10. Validation and Scenario Analysis of a Soil Organic Carbon Model

    Institute of Scientific and Technical Information of China (English)

    HUANG Yao; LIU Shi-liang; SHEN Qi-rong; ZONG Liang-gang; JIANG Ding-an; HUANG Hong-guang

    2002-01-01

    A model developed by the authors was validated against independent data sets. The data sets were obtained from field experiments of crop residue decomposition and a 7-year soil improvement in Yixing City, Jiangsu Province. Model validation indicated that soil organic carbon dynamics can be simulated from the weather variables of temperature, sunlight and precipitation, soil clay content and bulk density, grain yield of previous crops, qualities and quantities of the added organic matter. Model simulation in general agreed with the measurements. The comparison between computed and measured resulted in correlation coefficient γ2 values of 0.9291 * * * (n = 48) and 0. 6431 * * (n = 65) for the two experiments, respectively. Model prediction under three scenarios of no additional organic matter input, with an annual incorporation of rice and wheat straw at rates of 6.75t/ha and 9.0t/ha suggested that the soil organic carbon in Wanshi Township of Yixing City would be from an initial value of 7.85g/kg in 1983 to 6.30g/kg, 11.42g/kg and 13g/kg in 2014, respectively. Consequently, total nitrogen content of the soil was predicted to be respectively 0.49g/kg,0.89g/kg and 1.01g/kg under the three scenarios.

  11. Waste Reduction Model (WARM) Resources for Small Businesses and Organizations

    Science.gov (United States)

    This page provides a brief overview of how EPA’s Waste Reduction Model (WARM) can be used by small businesses and organizations. The page includes a brief summary of uses of WARM for the audience and links to other resources.

  12. An Integrated Model for Effective Knowledge Management in Chinese Organizations

    Science.gov (United States)

    An, Xiaomi; Deng, Hepu; Wang, Yiwen; Chao, Lemen

    2013-01-01

    Purpose: The purpose of this paper is to provide organizations in the Chinese cultural context with a conceptual model for an integrated adoption of existing knowledge management (KM) methods and to improve the effectiveness of their KM activities. Design/methodology/approaches: A comparative analysis is conducted between China and the western…

  13. Promoting Representational Competence with Molecular Models in Organic Chemistry

    Science.gov (United States)

    Stull, Andrew T.; Gainer, Morgan; Padalkar, Shamin; Hegarty, Mary

    2016-01-01

    Mastering the many different diagrammatic representations of molecules used in organic chemistry is challenging for students. This article summarizes recent research showing that manipulating 3-D molecular models can facilitate the understanding and use of these representations. Results indicate that students are more successful in translating…

  14. Editorial: Plant organ abscission: from models to crops

    Science.gov (United States)

    The shedding of plant organs is a highly coordinated process essential for both vegetative and reproductive development (Addicott, 1982; Sexton and Roberts, 1982; Roberts et al., 2002; Leslie et al., 2007; Roberts and Gonzalez-Carranza, 2007; Estornell et al., 2013). Research with model plants, name...

  15. A Process Model for the Comprehension of Organic Chemistry Notation

    Science.gov (United States)

    Havanki, Katherine L.

    2012-01-01

    This dissertation examines the cognitive processes individuals use when reading organic chemistry equations and factors that affect these processes, namely, visual complexity of chemical equations and participant characteristics (expertise, spatial ability, and working memory capacity). A six stage process model for the comprehension of organic…

  16. SOMPROF: A vertically explicit soil organic matter model

    NARCIS (Netherlands)

    Braakhekke, M.C.; Beer, M.; Hoosbeek, M.R.; Kruijt, B.; Kabat, P.

    2011-01-01

    Most current soil organic matter (SOM) models represent the soil as a bulk without specification of the vertical distribution of SOM in the soil profile. However, the vertical SOM profile may be of great importance for soil carbon cycling, both on short (hours to years) time scale, due to

  17. Promoting Representational Competence with Molecular Models in Organic Chemistry

    Science.gov (United States)

    Stull, Andrew T.; Gainer, Morgan; Padalkar, Shamin; Hegarty, Mary

    2016-01-01

    Mastering the many different diagrammatic representations of molecules used in organic chemistry is challenging for students. This article summarizes recent research showing that manipulating 3-D molecular models can facilitate the understanding and use of these representations. Results indicate that students are more successful in translating…

  18. Supramolecular organization of functional organic materials in the bulk and at organic/organic interfaces: a modeling and computer simulation approach.

    Science.gov (United States)

    Muccioli, Luca; D'Avino, Gabriele; Berardi, Roberto; Orlandi, Silvia; Pizzirusso, Antonio; Ricci, Matteo; Roscioni, Otello Maria; Zannoni, Claudio

    2014-01-01

    The molecular organization of functional organic materials is one of the research areas where the combination of theoretical modeling and experimental determinations is most fruitful. Here we present a brief summary of the simulation approaches used to investigate the inner structure of organic materials with semiconducting behavior, paying special attention to applications in organic photovoltaics and clarifying the often obscure jargon hindering the access of newcomers to the literature of the field. Special attention is paid to the choice of the computational "engine" (Monte Carlo or Molecular Dynamics) used to generate equilibrium configurations of the molecular system under investigation and, more importantly, to the choice of the chemical details in describing the molecular interactions. Recent literature dealing with the simulation of organic semiconductors is critically reviewed in order of increasing complexity of the system studied, from low molecular weight molecules to semiflexible polymers, including the challenging problem of determining the morphology of heterojunctions between two different materials.

  19. Modeling secondary organic aerosol formation through cloud processing of organic compounds

    Directory of Open Access Journals (Sweden)

    J. Chen

    2007-10-01

    Full Text Available Interest in the potential formation of secondary organic aerosol (SOA through reactions of organic compounds in condensed aqueous phases is growing. In this study, the potential formation of SOA from irreversible aqueous-phase reactions of organic species in clouds was investigated. A new proposed aqueous-phase chemistry mechanism (AqChem is coupled with the existing gas-phase Caltech Atmospheric Chemistry Mechanism (CACM and the Model to Predict the Multiphase Partitioning of Organics (MPMPO that simulate SOA formation. AqChem treats irreversible organic reactions that lead mainly to the formation of carboxylic acids, which are usually less volatile than the corresponding aldehydic compounds. Zero-dimensional model simulations were performed for tropospheric conditions with clouds present for three consecutive hours per day. Zero-dimensional model simulations show that 48-h average SOA formation is increased by 27% for a rural scenario with strong monoterpene emissions and 7% for an urban scenario with strong emissions of aromatic compounds, respectively, when irreversible organic reactions in clouds are considered. AqChem was also incorporated into the Community Multiscale Air Quality Model (CMAQ version 4.4 with CACM/MPMPO and applied to a previously studied photochemical episode (3–4 August 2004 focusing on the eastern United States. The CMAQ study indicates that the maximum contribution of SOA formation from irreversible reactions of organics in clouds is 0.28 μg m−3 for 24-h average concentrations and 0.60 μg m−3 for one-hour average concentrations at certain locations. On average, domain-wide surface SOA predictions for the episode are increased by 9% when irreversible, in-cloud processing of organics is considered. Because aldehydes of carbon number greater than four are assumed to convert fully to the corresponding carboxylic acids upon reaction with OH in cloud droplets and this assumption may overestimate

  20. The evolution of farnesoid X, vitamin D, and pregnane X receptors: insights from the green-spotted pufferfish (Tetraodon nigriviridis and other non-mammalian species

    Directory of Open Access Journals (Sweden)

    Kullman Seth W

    2011-02-01

    Full Text Available Abstract Background The farnesoid X receptor (FXR, pregnane X receptor (PXR, and vitamin D receptor (VDR are three closely related nuclear hormone receptors in the NR1H and 1I subfamilies that share the property of being activated by bile salts. Bile salts vary significantly in structure across vertebrate species, suggesting that receptors binding these molecules may show adaptive evolutionary changes in response. We have previously shown that FXRs from the sea lamprey (Petromyzon marinus and zebrafish (Danio rerio are activated by planar bile alcohols found in these two species. In this report, we characterize FXR, PXR, and VDR from the green-spotted pufferfish (Tetraodon nigriviridis, an actinopterygian fish that unlike the zebrafish has a bile salt profile similar to humans. We utilize homology modelling, docking, and pharmacophore studies to understand the structural features of the Tetraodon receptors. Results Tetraodon FXR has a ligand selectivity profile very similar to human FXR, with strong activation by the synthetic ligand GW4064 and by the primary bile acid chenodeoxycholic acid. Homology modelling and docking studies suggest a ligand-binding pocket architecture more similar to human and rat FXRs than to lamprey or zebrafish FXRs. Tetraodon PXR was activated by a variety of bile acids and steroids, although not by the larger synthetic ligands that activate human PXR such as rifampicin. Homology modelling predicts a larger ligand-binding cavity than zebrafish PXR. We also demonstrate that VDRs from the pufferfish and Japanese medaka were activated by small secondary bile acids such as lithocholic acid, whereas the African clawed frog VDR was not. Conclusions Our studies provide further evidence of the relationship between both FXR, PXR, and VDR ligand selectivity and cross-species variation in bile salt profiles. Zebrafish and green-spotted pufferfish provide a clear contrast in having markedly different primary bile salt profiles

  1. Sustainable Organic Farming For Environmental Health A Social Development Model

    Directory of Open Access Journals (Sweden)

    Ijun Rijwan Susanto

    2015-05-01

    Full Text Available ABSTRACT In this study the researcher attempted 1 to understand the basic features of organic farming in The Paguyuban Pasundans Cianjur 2 to describe and understand how the stakeholders were are able to internalize the challenges of organic farming on their lived experiences in the community 3 to describe and understand how the stakeholders were are able to internalize and applied the values of benefits of organic farming in support of environmental health on their lived experiences in the community 4 The purpose was to describe and understand how the stakeholders who are able to articulate their ideas regarding the model of sustainable organic farming 5 The Policy Recommendation for Organic Farming. The researcher employed triangulation thorough finding that provides breadth and depth to an investigation offering researchers a more accurate picture of the phenomenon. In the implementation of triangulation researchers conducted several interviews to get saturation. After completion of the interview results are written compiled and shown to the participants to check every statement by every participant. In addition researchers also checked the relevant documents and direct observation in the field The participants of this study were the stakeholders namely 1 The leader of Paguyuban Pasundans Organic Farmer Cianjur PPOFC 2 Members of Paguyuban Pasundans Organic FarmersCianjur 3 Leader of NGO 4 Government officials of agriculture 5 Business of organic food 6 and Consumer of organic food. Generally the findings of the study revealed the following 1 PPOFC began to see the reality as the impact of modern agriculture showed in fertility problems due to contaminated soil by residues of agricultural chemicals such as chemical fertilizers and chemical pesticides. So he wants to restore the soil fertility through environmentally friendly of farming practices 2 the challenges of organic farming on their lived experiences in the community farmers did not

  2. Global Modeling of the Oceanic Source of Organic Aerosols

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    Stelios Myriokefalitakis

    2010-01-01

    Full Text Available The global marine organic aerosol budget is investigated by a 3-dimensional chemistry-transport model considering recently proposed parameterisations of the primary marine organic aerosol (POA and secondary organic aerosol (SOA formation from the oxidation of marine volatile organic compounds. MODIS and SeaWiFS satellite data of Chlorophyll-a and ECMWF solar incoming radiation, wind speed, and temperature are driving the oceanic emissions in the model. Based on the adopted parameterisations, the SOA and the submicron POA marine sources are evaluated at about 5 Tg yr−1 (∼1.5 Tg C yr−1 and 7 to 8 Tg yr−1 (∼4 Tg C yr−1, respectively. The computed marine SOA originates from the dimethylsulfide oxidation (∼78%, the potentially formed dialkyl amine salts (∼21%, and marine hydrocarbon oxidation (∼0.1%. Comparison of calculations with observations indicates an additional marine source of soluble organic carbon that could be partially encountered by marine POA chemical ageing.

  3. Accounting for microbial habitats in modeling soil organic matter dynamics

    Science.gov (United States)

    Chenu, Claire; Garnier, Patricia; Nunan, Naoise; Pot, Valérie; Raynaud, Xavier; Vieublé, Laure; Otten, Wilfred; Falconer, Ruth; Monga, Olivier

    2017-04-01

    The extreme heterogeneity of soils constituents, architecture and inhabitants at the microscopic scale is increasingly recognized. Microbial communities exist and are active in a complex 3-D physical framework of mineral and organic particles defining pores of various sizes, more or less inter-connected. This results in a frequent spatial disconnection between soil carbon, energy sources and the decomposer organisms and a variety of microhabitats that are more or less suitable for microbial growth and activity. However, current biogeochemical models account for C dynamics at the macroscale (cm, m) and consider time- and spatially averaged relationships between microbial activity and soil characteristics. Different modelling approaches have intended to account for this microscale heterogeneity, based either on considering aggregates as surrogates for microbial habitats, or pores. Innovative modelling approaches are based on an explicit representation of soil structure at the fine scale, i.e. at µm to mm scales: pore architecture and their saturation with water, localization of organic resources and of microorganisms. Three recent models are presented here, that describe the heterotrophic activity of either bacteria or fungi and are based upon different strategies to represent the complex soil pore system (Mosaic, LBios and µFun). These models allow to hierarchize factors of microbial activity in soil's heterogeneous architecture. Present limits of these approaches and challenges are presented, regarding the extensive information required on soils at the microscale and to up-scale microbial functioning from the pore to the core scale.

  4. Model Based Fuzzy Expert System for Measuring Organization Knowledge Management

    Directory of Open Access Journals (Sweden)

    Houshang Taghizadeh

    2012-02-01

    Full Text Available This paper presents a model based on fuzzy set theory for determining the score of knowledge management in organization. The introduced model has five stages. In the first stage, input and output variable of model are characterized by available theories. Inputs are as follows: knowledge acquisition, knowledge storage, knowledge creation, knowledge sharing and knowledge transfer. The output is as follow score of knowledge management in organization. In the second stage, the input and output are converted into fuzzy numbers after classification. Inference rules are explained in the third stage. In the fourth stage, defuzzification is performed, and in the fifth stage, the devised system is tested. The test result shows that the presented model has high validity. Ultimately, by using the designed model, the score of knowledge management for Tabriz Kar machinery industry was calculated. The statistical population consists of 50 members of this organization. All the population has been studied. A questionnaire was devised, and its validity and reliability were confirmed. The result indicated that the score of knowledge management in Tabriz Kar machinery industry with the membership rank of 0.924 was at an average level and with the membership rank of 0.076 was at a high

  5. Modeling organic nitrogen conversions in activated sludge bioreactors.

    Science.gov (United States)

    Makinia, Jacek; Pagilla, Krishna; Czerwionka, Krzysztof; Stensel, H David

    2011-01-01

    For biological nutrient removal (BNR) systems designed to maximize nitrogen removal, the effluent total nitrogen (TN) concentration may range from 2.0 to 4.0 g N/m(3) with about 25-50% in the form of organic nitrogen (ON). In this study, current approaches to modeling organic N conversions (separate processes vs. constant contents of organic fractions) were compared. A new conceptual model of ON conversions was developed and combined with Activated Sludge Model No. 2d (ASM2d). The model addresses a new insight into the processes of ammonification, biomass decay and hydrolysis of particulate and colloidal ON (PON and CON, respectively). Three major ON fractions incorporated are defined as dissolved (DON) (model parameter set, the behaviors of both inorganic N forms (NH4-N, NOX-N) and ON forms (DON, CON) in the batch experiments were predicted. The challenges to accurately simulate and predict effluent ON levels from BNR systems are due to analytical methods of direct ON measurement (replacing TKN) and lack of large enough database (in-process measurements, dynamic variations of the ON concentrations) which can be used to determine parameter value ranges.

  6. THE MODEL OF EXTERNSHIP ORGANIZATION FOR FUTURE TEACHERS: QUALIMETRIC APPROACH

    Directory of Open Access Journals (Sweden)

    Taisiya A. Isaeva

    2015-01-01

    Full Text Available The aim of the paper is to present author’s model for bachelors – future teachers of vocational training. The model is been worked out from the standpoint of qualimetric approach and provides a pedagogical training.Methods. The process is based on the literature analysis of externship organization for students in higher education and includes the SWOT-analysis techniques in pedagogical training. The method of group expert evaluation is the main method of pedagogical qualimetry. Structural components of professional pedagogical competency of students-future teachers are defined. It allows us to determine a development level and criterion of estimation on mastering programme «Vocational training (branch-wise».Results. This article interprets the concept «pedagogical training»; its basic organization principles during students’ practice are stated. The methods of expert group formation are presented: self-assessment and personal data.Scientific novelty. The externship organization model for future teachers is developed. This model is based on pedagogical training, using qualimetric approach and the SWOT-analysis techniques. Proposed criterion-assessment procedures are managed to determine the developing levels of professional and pedagogical competency.Practical significance. The model is introduced into pedagogical training of educational process of Kalashnikov’s Izhevsk State Technical University, and can be used in other similar educational establishments.

  7. Self-organizing model of motor cortical activities during drawing

    Science.gov (United States)

    Lin, Siming H.; Si, Jennie; Schwartz, Andrew B.

    1996-05-01

    The population vector algorithm has been developed to combine the simultaneous direction- related activities of a population of motor cortical neurons to predict the trajectory of the arm movement. In our study, we consider a self-organizing model of a neural representation of the arm trajectory based on neuronal discharge rates. Self-organizing feature mapping (SOFM) is used to select the optimal set of weights in the model to determine the contribution of individual neuron to the overall movement. The correspondence between the movement directions and the discharge patterns of the motor cortical neurons is established in the output map. The topology preserving property of the SOFM is used to analyze real recorded data of a behavior monkey. The data used in this analysis were taken while the monkey was drawing spirals and doing the center out movement. Using such a statistical model, the monkey's arm moving directions could be well predicted based on the motor cortex neuronal firing information.

  8. Rotation in turbulence of aquatic organisms modeled as particles

    Science.gov (United States)

    Variano, Evan; Byron, Margaret; Bellani, Gabriele

    2012-11-01

    We investigate which length and time scales are relevant for determining the rotation of aquatic organisms and their gametes. We are interested in parameter space beyond the Stokes regime, and also the effect of particle shape on rotation. We report experimental measurements that use custom-manufactured particles to model aquatic organisms, which are designed with the necessary optical properties so that we can measure their rotation, simultaneously with the vorticity statistics of the surrounding fluid. Lagrangian timeseries of particles' angular velocity allows investigation of rotational diffusion.

  9. Modeling stable isotope and organic carbon in hillslope stormflow

    Science.gov (United States)

    Dusek, Jaromir; Vogel, Tomas; Dohnal, Michal; Marx, Anne; Jankovec, Jakub; Sanda, Martin; Votrubova, Jana; Barth, Johannes A. C.; Cislerova, Milena

    2016-04-01

    Reliable prediction of water movement and fluxes of dissolved substances (such as stable isotopes and organic carbon) at both the hillslope and the catchment scales remains a challenge due to complex boundary conditions and soil spatial heterogeneity. In addition, microbially mediated transformations of dissolved organic carbon (DOC) are known to affect balance of DOC in soils, hence the transformations need to be included in a conceptual model of a DOC transport. So far, only few studies utilized stable isotope information in modeling and even fewer linked dissolved carbon fluxes to mixing and/or transport models. In this study, stormflow dynamics of oxygen-18 isotope and dissolved organic carbon was analyzed using a physically based modeling approach. One-dimensional dual-continuum vertical flow and transport model, based on Richards and advection-dispersion equations, was used to simulate the subsurface transport processes in a forest soil during several observed rainfall-runoff episodes. The transport of heat in the soil profile was described by conduction-advection equation. Water flow and transport of solutes and heat were assumed to take place in two mutually communicating porous domains, the soil matrix and the network of preferential pathways. The rate of microbial transformations of DOC was assumed to depend on soil water content and soil temperature. Oxygen-18 and dissolved organic carbon concentrations were observed in soil pore water, hillslope stormflow (collected in the experimental hillslope trench), and stream discharge (at the catchment outlet). The modeling was used to analyze the transformation of input solute signals into output hillslope signals observed in the trench stormflow. Signatures of oxygen-18 isotope in hillslope stormflow as well as isotope concentration in soil pore water were predicted reasonably well. Due to complex nature of microbial transformations, prediction of DOC rate and transport was associated with a high uncertainty.

  10. Experimentation and modeling of organic photocontamination on lithographic optics

    Science.gov (United States)

    Kunz, Roderick R.; Liberman, Vladimir; Downs, Deanna K.

    2000-07-01

    Photodeposition of organic films on transparent substrates irradiated in the presence of trace levels of hydrocarbons has been experimentally investigated and a model is presented that describes the film growth behavior. The efficacy of a given organic precursor at forming a deposit is proportional to the product of its surface coverage and by its photon absorption cross section. These measurement are important in predicting the transmission characteristics of lithographic optics operating at 157-, 193-, and 248-nm wavelength. For example, a lens element irradiated continuously for one year in the presence of 1 part per billion of t-butyl benzene would exhibit a transmission of approximately 87 percent at 193 nm. The effects of oxygen- containing ambients are also documented, and methods for elimination and/or prevention of organic contamination are suggested.

  11. Organic livestock production systems as a model of sustainability development

    Directory of Open Access Journals (Sweden)

    Mariano Pauselli

    2010-01-01

    Full Text Available Organic farming and livestock production offer effective means of satisfying consumer demand for healthy and safe foods and reducing the environmental pressure of agricultural production. In Mediterranean areas organic livestock production could be considered a feasible systems to improve rural development in unfavourable areas and to maintain rural landscape. Constrains, like pasture availability during the year, determine the evolution of different strategies in livestock rearing to improve or maintain net income of population. Moreover the evaluation of the sustainability using a holistic approach using assessment criteria like Life Cycle Assessment (LCA and Emergy Assessment could be considered models to evaluate organic and conventional livestock production sustainability and at the same time new research fields.

  12. IT Business Value Model for Information Intensive Organizations

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Gastaud Maçada

    2012-01-01

    Full Text Available Many studies have highlighted the capacity Information Technology (IT has for generating value for organizations. Investments in IT made by organizations have increased each year. Therefore, the purpose of the present study is to analyze the IT Business Value for Information Intensive Organizations (IIO - e.g. banks, insurance companies and securities brokers. The research method consisted of a survey that used and combined the models from Weill and Broadbent (1998 and Gregor, Martin, Fernandez, Stern and Vitale (2006. Data was gathered using an adapted instrument containing 5 dimensions (Strategic, Informational, Transactional, Transformational and Infra-structure with 27 items. The instrument was refined by employing statistical techniques such as Exploratory and Confirmatory Factorial Analysis through Structural Equations (first and second order Model Measurement. The final model is composed of four factors related to IT Business Value: Strategic, Informational, Transactional and Transformational, arranged in 15 items. The dimension Infra-structure was excluded during the model refinement process because it was discovered during interviews that managers were unable to perceive it as a distinct dimension of IT Business Value.

  13. Modeling self-organizing traffic lights with elementary cellular automata

    CERN Document Server

    Gershenson, Carlos

    2009-01-01

    There have been several highway traffic models proposed based on cellular automata. The simplest one is elementary cellular automaton rule 184. We extend this model to city traffic with cellular automata coupled at intersections using only rules 184, 252, and 136. The simplicity of the model offers a clear understanding of the main properties of city traffic and its phase transitions. We use the proposed model to compare two methods for coordinating traffic lights: a green-wave method that tries to optimize phases according to expected flows and a self-organizing method that adapts to the current traffic conditions. The self-organizing method delivers considerable improvements over the green-wave method. For low densities, the self-organizing method promotes the formation and coordination of platoons that flow freely in four directions, i.e. with a maximum velocity and no stops. For medium densities, the method allows a constant usage of the intersections, exploiting their maximum flux capacity. For high dens...

  14. Nonequilibrium drift-diffusion model for organic semiconductor devices

    Science.gov (United States)

    Felekidis, Nikolaos; Melianas, Armantas; Kemerink, Martijn

    2016-07-01

    Two prevailing formalisms are currently used to model charge transport in organic semiconductor devices. Drift-diffusion calculations, on the one hand, are time effective but assume local thermodynamic equilibrium, which is not always realistic. Kinetic Monte Carlo models, on the other hand, do not require this assumption but are computationally expensive. Here, we present a nonequilibrium drift-diffusion model that bridges this gap by fusing the established multiple trap and release formalism with the drift-diffusion transport equation. For a prototypical photovoltaic system the model is shown to quantitatively describe, with a single set of parameters, experiments probing (1) temperature-dependent steady-state charge transport—space-charge limited currents, and (2) time-resolved charge transport and relaxation of nonequilibrated photocreated charges. Moreover, the outputs of the developed kinetic drift-diffusion model are an order of magnitude, or more, faster to compute and in good agreement with kinetic Monte Carlo calculations.

  15. Modeling regional secondary organic aerosol using the Master Chemical Mechanism

    Science.gov (United States)

    Li, Jingyi; Cleveland, Meredith; Ziemba, Luke D.; Griffin, Robert J.; Barsanti, Kelley C.; Pankow, James F.; Ying, Qi

    2015-02-01

    A modified near-explicit Master Chemical Mechanism (MCM, version 3.2) with 5727 species and 16,930 reactions and an equilibrium partitioning module was incorporated into the Community Air Quality Model (CMAQ) to predict the regional concentrations of secondary organic aerosol (SOA) from volatile organic compounds (VOCs) in the eastern United States (US). In addition to the semi-volatile SOA from equilibrium partitioning, reactive surface uptake processes were used to simulate SOA formation due to isoprene epoxydiol, glyoxal and methylglyoxal. The CMAQ-MCM-SOA model was applied to simulate SOA formation during a two-week episode from August 28 to September 7, 2006. The southeastern US has the highest SOA, with a maximum episode-averaged concentration of ∼12 μg m-3. Primary organic aerosol (POA) and SOA concentrations predicted by CMAQ-MCM-SOA agree well with AMS-derived hydrocarbon-like organic aerosol (HOA) and oxygenated organic aerosol (OOA) urban concentrations at the Moody Tower at the University of Houston. Predicted molecular properties of SOA (O/C, H/C, N/C and OM/OC ratios) at the site are similar to those reported in other urban areas, and O/C values agree with measured O/C at the same site. Isoprene epoxydiol is predicted to be the largest contributor to total SOA concentration in the southeast US, followed by methylglyoxal and glyoxal. The semi-volatile SOA components are dominated by products from β-caryophyllene oxidation, but the major species and their concentrations are sensitive to errors in saturation vapor pressure estimation. A uniform decrease of saturation vapor pressure by a factor of 100 for all condensable compounds can lead to a 150% increase in total SOA. A sensitivity simulation with UNIFAC-calculated activity coefficients (ignoring phase separation and water molecule partitioning into the organic phase) led to a 10% change in the predicted semi-volatile SOA concentrations.

  16. Model Establishment for Simulating Soil Organic Carbon Dynamics

    Institute of Scientific and Technical Information of China (English)

    HUANG Yao; LIU Shi-liang; SHEN Qi-rong; ZONG Liang-gang

    2002-01-01

    Assuming that decomposition of organic matter in soils follows the first-order kinetics reaction,a computer model was developed to simulate soil organic matter dynamics. Organic matter in soils is divided up into two parts that include incorporated organic carbon from crop residues or other organic fertilizer and soil intrinsic carbon. The incorporated organic carbon was assumed to consist of two components, labile-C and resistant-C. The model was represented by a differential equation of dCi/dt = Ki× fT × fw × fs × Ci ( i = l,r, S ) and an integral equation of Cit = Cio × EXP ( Ki X fT X fw X fs X t ). Effect of soil parameters of temperature, moisture and texture on the decomposition was functioned by the fT, fw and fs, respectively.Data from laboratory incubation experiments were used to determine the first-order decay rate Ki and the fraction of labile-C of crop residues by employing a nonlinear method. The values of K for the components of labile-C and resistant-C and the soil intrinsic carbon were evaluated to be 0. 025,0. 080 × 10-2 and 0. 065 ×10-3d-1, respectively. The labile-C fraction of wheat straw, wheat roots, rice straw and rice roots were0.50, 0.25, 0.40 and 0.20, respectively. These values are related to the initial residue carbon-to-nitrogen ratio ( C/N) and lignin content.

  17. Mobility dependent recombination models for organic solar cells

    Science.gov (United States)

    Wagenpfahl, Alexander

    2017-09-01

    Modern solar cell technologies are driven by the effort to enhance power conversion efficiencies. A main mechanism limiting power conversion efficiencies is charge carrier recombination which is a direct function of the encounter probability of both recombination partners. In inorganic solar cells with rather high charge carrier mobilities, charge carrier recombination is often dominated by energetic states which subsequently trap both recombination partners for recombination. Free charge carriers move fast enough for Coulomb attraction to be irrelevant for the encounter probability. Thus, charge carrier recombination is independent of charge carrier mobilities. In organic semiconductors charge carrier mobilities are much lower. Therefore, electrons and holes have more time react to mutual Coulomb-forces. This results in the strong charge carrier mobility dependencies of the observed charge carrier recombination rates. In 1903 Paul Langevin published a fundamental model to describe the recombination of ions in gas-phase or aqueous solutions, known today as Langevin recombination. During the last decades this model was used to interpret and model recombination in organic semiconductors. However, certain experiments especially with bulk-heterojunction solar cells reveal much lower recombination rates than predicted by Langevin. In search of an explanation, many material and device properties such as morphology and energetic properties have been examined in order to extend the validity of the Langevin model. A key argument for most of these extended models is, that electron and hole must find each other at a mutual spatial location. This encounter may be limited for instance by trapping of charges in trap states, by selective electrodes separating electrons and holes, or simply by the morphology of the involved semiconductors, making it impossible for electrons and holes to recombine at high rates. In this review, we discuss the development of mobility limited

  18. Model evaluation of marine primary organic aerosol emission schemes

    Directory of Open Access Journals (Sweden)

    B. Gantt

    2012-09-01

    Full Text Available In this study, several marine primary organic aerosol (POA emission schemes have been evaluated using the GEOS-Chem chemical transport model in order to provide guidance for their implementation in air quality and climate models. These emission schemes, based on varying dependencies of chlorophyll a concentration ([chl a] and 10 m wind speed (U10, have large differences in their magnitude, spatial distribution, and seasonality. Model comparison with weekly and monthly mean values of the organic aerosol mass concentration at two coastal sites shows that the source function exclusively related to [chl a] does a better job replicating surface observations. Sensitivity simulations in which the negative U10 and positive [chl a] dependence of the organic mass fraction of sea spray aerosol are enhanced show improved prediction of the seasonality of the marine POA concentrations. A top-down estimate of submicron marine POA emissions based on the parameterization that compares best to the observed weekly and monthly mean values of marine organic aerosol surface concentrations has a global average emission rate of 6.3 Tg yr−1. Evaluation of existing marine POA source functions against a case study during which marine POA contributed the major fraction of submicron aerosol mass shows that none of the existing parameterizations are able to reproduce the hourly-averaged observations. Our calculations suggest that in order to capture episodic events and short-term variability in submicron marine POA concentration over the ocean, new source functions need to be developed that are grounded in the physical processes unique to the organic fraction of sea spray aerosol.

  19. Model evaluation of marine primary organic aerosol emission schemes

    Science.gov (United States)

    Gantt, B.; Johnson, M. S.; Meskhidze, N.; Sciare, J.; Ovadnevaite, J.; Ceburnis, D.; O'Dowd, C. D.

    2012-09-01

    In this study, several marine primary organic aerosol (POA) emission schemes have been evaluated using the GEOS-Chem chemical transport model in order to provide guidance for their implementation in air quality and climate models. These emission schemes, based on varying dependencies of chlorophyll a concentration ([chl a]) and 10 m wind speed (U10), have large differences in their magnitude, spatial distribution, and seasonality. Model comparison with weekly and monthly mean values of the organic aerosol mass concentration at two coastal sites shows that the source function exclusively related to [chl a] does a better job replicating surface observations. Sensitivity simulations in which the negative U10 and positive [chl a] dependence of the organic mass fraction of sea spray aerosol are enhanced show improved prediction of the seasonality of the marine POA concentrations. A top-down estimate of submicron marine POA emissions based on the parameterization that compares best to the observed weekly and monthly mean values of marine organic aerosol surface concentrations has a global average emission rate of 6.3 Tg yr-1. Evaluation of existing marine POA source functions against a case study during which marine POA contributed the major fraction of submicron aerosol mass shows that none of the existing parameterizations are able to reproduce the hourly-averaged observations. Our calculations suggest that in order to capture episodic events and short-term variability in submicron marine POA concentration over the ocean, new source functions need to be developed that are grounded in the physical processes unique to the organic fraction of sea spray aerosol.

  20. Dissecting genetic and environmental mutation signatures with model organisms.

    Science.gov (United States)

    Segovia, Romulo; Tam, Annie S; Stirling, Peter C

    2015-08-01

    Deep sequencing has impacted on cancer research by enabling routine sequencing of genomes and exomes to identify genetic changes associated with carcinogenesis. Researchers can now use the frequency, type, and context of all mutations in tumor genomes to extract mutation signatures that reflect the driving mutational processes. Identifying mutation signatures, however, may not immediately suggest a mechanism. Consequently, several recent studies have employed deep sequencing of model organisms exposed to discrete genetic or environmental perturbations. These studies exploit the simpler genomes and availability of powerful genetic tools in model organisms to analyze mutation signatures under controlled conditions, forging mechanistic links between mutational processes and signatures. We discuss the power of this approach and suggest that many such studies may be on the horizon.

  1. Semantic network based component organization model for program mining

    Institute of Scientific and Technical Information of China (English)

    王斌; 张尧学; 陈松乔

    2003-01-01

    Based on the definition of component ontology, an effective component classification mechanism and a facet named component relationship are proposed. Then an application domain oriented, hierarchical component organization model is established. At last a hierarchical component semantic network (HCSN) described by ontology interchange language(OIL) is presented and then its function is described. Using HCSN and cooperating with other components retrieving algorithms based on component description, other components information and their assembly or composite modes related to the key component can be found. Based on HCSN, component directory library is catalogued and a prototype system is constructed. The prototype system proves that component library organization based on this model gives guarantee to the reliability of component assembly during program mining.

  2. Cube Kohonen self-organizing map (CKSOM) model with new equations in organizing unstructured data.

    Science.gov (United States)

    Lim, Seng Poh; Haron, Habibollah

    2013-09-01

    Surface reconstruction by using 3-D data is used to represent the surface of an object and perform important tasks. The type of data used is important and can be described as either structured or unstructured. For unstructured data, there is no connectivity information between data points. As a result, incorrect shapes will be obtained during the imaging process. Therefore, the data should be reorganized by finding the correct topology so that the correct shape can be obtained. Previous studies have shown that the Kohonen self-organizing map (KSOM) could be used to solve data organizing problems. However, 2-D Kohonen maps are limited because they are unable to cover the whole surface of closed 3-D surface data. Furthermore, the neurons inside the 3-D KSOM structure should be removed in order to create a correct wireframe model. This is because only the outside neurons are used to represent the surface of an object. The aim of this paper is to use KSOM to organize unstructured data for closed surfaces. KSOM isused in this paper by testing its ability to organize medical image data because KSOM is mostly used in constructing engineering field data. Enhancements are added to the model by introducing class number and the index vector, and new equations are created. Various grid sizes and maximum iterations are tested in the experiments. Based on the results, the number of redundancies is found to be directly proportional to the grid size. When we increase the maximum iterations, the surface of the image becomes smoother. An area formula is used and manual calculations are performed to validate the results. This model is implemented and images are created using Dev C++ and GNUPlot.

  3. Mechanical models for the self-organization of tubular patterns.

    Science.gov (United States)

    Guo, Chin-Lin

    2013-01-01

    Organogenesis, such as long tubule self-organization, requires long-range coordination of cell mechanics to arrange cell positions and to remodel the extracellular matrix. While the current mainstream in the field of tissue morphogenesis focuses primarily on genetics and chemical signaling, the influence of cell mechanics on the programming of patterning cues in tissue morphogenesis has not been adequately addressed. Here, we review experimental evidence and propose quantitative mechanical models by which cells can create tubular patterns.

  4. Spatial self-organization in hybrid models of multicellular adhesion

    Science.gov (United States)

    Bonforti, Adriano; Duran-Nebreda, Salva; Montañez, Raúl; Solé, Ricard

    2016-10-01

    Spatial self-organization emerges in distributed systems exhibiting local interactions when nonlinearities and the appropriate propagation of signals are at work. These kinds of phenomena can be modeled with different frameworks, typically cellular automata or reaction-diffusion systems. A different class of dynamical processes involves the correlated movement of agents over space, which can be mediated through chemotactic movement or minimization of cell-cell interaction energy. A classic example of the latter is given by the formation of spatially segregated assemblies when cells display differential adhesion. Here, we consider a new class of dynamical models, involving cell adhesion among two stochastically exchangeable cell states as a minimal model capable of exhibiting well-defined, ordered spatial patterns. Our results suggest that a whole space of pattern-forming rules is hosted by the combination of physical differential adhesion and the value of probabilities modulating cell phenotypic switching, showing that Turing-like patterns can be obtained without resorting to reaction-diffusion processes. If the model is expanded allowing cells to proliferate and die in an environment where diffusible nutrient and toxic waste are at play, different phases are observed, characterized by regularly spaced patterns. The analysis of the parameter space reveals that certain phases reach higher population levels than other modes of organization. A detailed exploration of the mean-field theory is also presented. Finally, we let populations of cells with different adhesion matrices compete for reproduction, showing that, in our model, structural organization can improve the fitness of a given cell population. The implications of these results for ecological and evolutionary models of pattern formation and the emergence of multicellularity are outlined.

  5. Numerical model of multilayer organic light-emitting devices

    Institute of Scientific and Technical Information of China (English)

    Hu Yue; Rao Hai-Bo

    2009-01-01

    A numerical model of multilayer organic light-emitting devices is presented in this article.This model is based on the drift-diffusion equations which include charge injection,transport,space charge effects,trapping,heterojunction interface and recombination process.The device structure in the simulation is ITO/CuPc(20 nm)/NPD(40 nm)/Alq3(60 nm)/LiF/Al.There are two heterojunctions which should be dealt with in the simulation.The Ⅰ-Ⅴ characteristics,carrier distribution and recombination rate of a device are calculated.The simulation results and measured data are in good agreement.

  6. Conceptual hierarchical modeling to describe wetland plant community organization

    Science.gov (United States)

    Little, A.M.; Guntenspergen, G.R.; Allen, T.F.H.

    2010-01-01

    Using multivariate analysis, we created a hierarchical modeling process that describes how differently-scaled environmental factors interact to affect wetland-scale plant community organization in a system of small, isolated wetlands on Mount Desert Island, Maine. We followed the procedure: 1) delineate wetland groups using cluster analysis, 2) identify differently scaled environmental gradients using non-metric multidimensional scaling, 3) order gradient hierarchical levels according to spatiotem-poral scale of fluctuation, and 4) assemble hierarchical model using group relationships with ordination axes and post-hoc tests of environmental differences. Using this process, we determined 1) large wetland size and poor surface water chemistry led to the development of shrub fen wetland vegetation, 2) Sphagnum and water chemistry differences affected fen vs. marsh / sedge meadows status within small wetlands, and 3) small-scale hydrologic differences explained transitions between forested vs. non-forested and marsh vs. sedge meadow vegetation. This hierarchical modeling process can help explain how upper level contextual processes constrain biotic community response to lower-level environmental changes. It creates models with more nuanced spatiotemporal complexity than classification and regression tree procedures. Using this process, wetland scientists will be able to generate more generalizable theories of plant community organization, and useful management models. ?? Society of Wetland Scientists 2009.

  7. Self-organized Collaboration Network Model Based on Module Emerging

    Science.gov (United States)

    Yang, Hongyong; Lu, Lan; Liu, Qiming

    Recently, the studies of the complex network have gone deep into many scientific fields, such as computer science, physics, mathematics, sociology, etc. These researches enrich the realization for complex network, and increase understands for the new characteristic of complex network. Based on the evolvement characteristic of the author collaboration in the scientific thesis, a self-organized network model of the scientific cooperation network is presented by module emerging. By applying the theoretical analysis, it is shown that this network model is a scale-free network, and the strength degree distribution and the module degree distribution of the network nodes have the same power law. In order to make sure the validity of the theoretical analysis for the network model, we create the computer simulation and demonstration collaboration network. By analyzing the data of the network, the results of the demonstration network and the computer simulation are consistent with that of the theoretical analysis of the model.

  8. Modelling nitrous oxide emissions from organic soils in Europe

    Science.gov (United States)

    Leppelt, Thomas; Dechow, Rene; Gebbert, Sören; Freibauer, Annette

    2013-04-01

    The greenhouse gas emission potential of peatland ecosystems are mandatory for a complete annual emission budget in Europe. The GHG-Europe project aims to improve the modelling capabilities for greenhouse gases, e.g., nitrous oxide. The heterogeneous and event driven fluxes of nitrous oxide are challenging to model on European scale, especially regarding the upscaling purpose and certain parameter estimations. Due to these challenges adequate techniques are needed to create a robust empirical model. Therefore a literature study of nitrous oxide fluxes from organic soils has been carried out. This database contains flux data from boreal and temperate climate zones and covers the different land use categories: cropland, grassland, forest, natural and peat extraction sites. Especially managed crop- and grassland sites feature high emission potential. Generally nitrous oxide emissions increases significantly with deep drainage and intensive application of nitrogen fertilisation. Whereas natural peatland sites with a near surface groundwater table can act as nitrous oxide sink. An empirical fuzzy logic model has been applied to predict annual nitrous oxide emissions from organic soils. The calibration results in two separate models with best model performances for bogs and fens, respectively. The derived parameter combinations of these models contain mean groundwater table, nitrogen fertilisation, annual precipitation, air temperature, carbon content and pH value. Influences of the calibrated parameters on nitrous oxide fluxes are verified by several studies in literature. The extrapolation potential has been tested by an implemented cross validation. Furthermore the parameter ranges of the calibrated models are compared to occurring values on European scale. This avoid unknown systematic errors for the regionalisation purpose. Additionally a sensitivity analysis specify the model behaviour for each alternating parameter. The upscaling process for European peatland

  9. Modelling erosion and its interaction with soil organic carbon.

    Science.gov (United States)

    Oyesiku-Blakemore, Joseph; Verrot, Lucile; Geris, Josie; Zhang, Ganlin; Peng, Xinhua; Hallett, Paul; Smith, Jo

    2017-04-01

    Water driven soil erosion removes and relocates a significant quantity of soil organic carbon. In China the quantity of carbon removed from the soil through water erosion has been reported to be 180+/-80 Mt y-1 (Yue et al., 2011). Being able to effectively model the movement of such a large quantity of carbon is important for the assessment of soil quality and carbon storage in the region and further afield. A large selection of erosion models are available and much work has been done on evaluating the performance of these in developed countries (Merritt et al., 2006). Fewer studies have evaluated the application of these models on soils in developing countries. Here we evaluate and compare the performance of two of these models, WEPP (Laflen et al., 1997) and RUSLE (Renard et al., 1991), for simulations of soil erosion and deposition at the slope scale on a Chinese Red Soil under cultivation using measurements taken at the site. We also describe work to dynamically couple the movement of carbon presented in WEPP to a model of soil organic matter and nutrient turnover, ECOSSE (Smith et al., 2010). This aims to improve simulations of both erosion and carbon cycling by using the simulated rates of erosion to alter the distribution of soil carbon, the depth of soil and the clay content across the slopes, changing the simulated rate of carbon turnover. This, in turn, affects the soil carbon available to be eroded in the next timestep, so improving estimates of carbon erosion. We compare the simulations of this coupled modelling approach with those of the unaltered ECOSSE and WEPP models to determine the importance of coupling erosion and turnover models on the simulation of carbon losses at catchment scale.

  10. Spatiotemporal Organization of Spin-Coated Supported Model Membranes

    Science.gov (United States)

    Simonsen, Adam Cohen

    All cells of living organisms are separated from their surroundings and organized internally by means of flexible lipid membranes. In fact, there is consensus that the minimal requirements for self-replicating life processes include the following three features: (1) information carriers (DNA, RNA), (2) a metabolic system, and (3) encapsulation in a container structure [1]. Therefore, encapsulation can be regarded as an essential part of life itself. In nature, membranes are highly diverse interfacial structures that compartmentalize cells [2]. While prokaryotic cells only have an outer plasma membrane and a less-well-developed internal membrane structure, eukaryotic cells have a number of internal membranes associated with the organelles and the nucleus. Many of these membrane structures, including the plasma membrane, are complex layered systems, but with the basic structure of a lipid bilayer. Biomembranes contain hundreds of different lipid species in addition to embedded or peripherally associated membrane proteins and connections to scaffolds such as the cytoskeleton. In vitro, lipid bilayers are spontaneously self-organized structures formed by a large group of amphiphilic lipid molecules in aqueous suspensions. Bilayer formation is driven by the entropic properties of the hydrogen bond network in water in combination with the amphiphilic nature of the lipids. The molecular shapes of the lipid constituents play a crucial role in bilayer formation, and only lipids with approximately cylindrical shapes are able to form extended bilayers. The bilayer structure of biomembranes was discovered by Gorter and Grendel in 1925 [3] using monolayer studies of lipid extracts from red blood cells. Later, a number of conceptual models were developed to rationalize the organization of lipids and proteins in biological membranes. One of the most celebrated is the fluid-mosaic model by Singer and Nicolson (1972) [4]. According to this model, the lipid bilayer component of

  11. Incorporating microbial ecology into the metabolic modelling of polyphosphate accumulating organisms and glycogen accumulating organisms.

    Science.gov (United States)

    Oehmen, A; Carvalho, G; Lopez-Vazquez, C M; van Loosdrecht, M C M; Reis, M A M

    2010-09-01

    In the enhanced biological phosphorus removal (EBPR) process, the competition between polyphosphate accumulating organisms (PAO) and glycogen accumulating organisms (GAO) has been studied intensively in recent years by both microbiologists and engineers, due to its important effects on phosphorus removal performance and efficiency. This study addresses the impact of microbial ecology on assessing the PAO-GAO competition through metabolic modelling, focussing on reviewing recent developments, discussion of how the results from molecular studies can impact the way we model the process, and offering perspectives for future research opportunities based on unanswered questions concerning PAO and GAO metabolism. Indeed, numerous findings that are seemingly contradictory could in fact be explained by the metabolic behaviour of different sub-groups of PAOs and/or GAOs exposed to different environmental and operational conditions. Some examples include the glycolysis pathway (i.e. Embden-Meyerhof-Parnas (EMP) vs. Entner-Doudoroff (ED)), denitrification capacity, anaerobic tricarboxylic acid (TCA) cycle activity and PAOs' ability to adjust their metabolism to e.g. a GAO-like metabolism. Metabolic modelling may further yield far-reaching influences on practical applications as well, and serves as a bridge between molecular/biochemical research studies and the optimisation of wastewater treatment plant operation. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. MIANN models in medicinal, physical and organic chemistry.

    Science.gov (United States)

    González-Díaz, Humberto; Arrasate, Sonia; Sotomayor, Nuria; Lete, Esther; Munteanu, Cristian R; Pazos, Alejandro; Besada-Porto, Lina; Ruso, Juan M

    2013-01-01

    Reducing costs in terms of time, animal sacrifice, and material resources with computational methods has become a promising goal in Medicinal, Biological, Physical and Organic Chemistry. There are many computational techniques that can be used in this sense. In any case, almost all these methods focus on few fundamental aspects including: type (1) methods to quantify the molecular structure, type (2) methods to link the structure with the biological activity, and others. In particular, MARCH-INSIDE (MI), acronym for Markov Chain Invariants for Networks Simulation and Design, is a well-known method for QSAR analysis useful in step (1). In addition, the bio-inspired Artificial-Intelligence (AI) algorithms called Artificial Neural Networks (ANNs) are among the most powerful type (2) methods. We can combine MI with ANNs in order to seek QSAR models, a strategy which is called herein MIANN (MI & ANN models). One of the first applications of the MIANN strategy was in the development of new QSAR models for drug discovery. MIANN strategy has been expanded to the QSAR study of proteins, protein-drug interactions, and protein-protein interaction networks. In this paper, we review for the first time many interesting aspects of the MIANN strategy including theoretical basis, implementation in web servers, and examples of applications in Medicinal and Biological chemistry. We also report new applications of the MIANN strategy in Medicinal chemistry and the first examples in Physical and Organic Chemistry, as well. In so doing, we developed new MIANN models for several self-assembly physicochemical properties of surfactants and large reaction networks in organic synthesis. In some of the new examples we also present experimental results which were not published up to date.

  13. Modeling uptake of hydrophobic organic contaminants into polyethylene passive samplers.

    Science.gov (United States)

    Thompson, Jay M; Hsieh, Ching-Hong; Luthy, Richard G

    2015-02-17

    Single-phase passive samplers are gaining acceptance as a method to measure hydrophobic organic contaminant (HOC) concentration in water. Although the relationship between the HOC concentration in water and passive sampler is linear at equilibrium, mass transfer models are needed for nonequilibrium conditions. We report measurements of organochlorine pesticide diffusion and partition coefficients with respect to polyethylene (PE), and present a Fickian approach to modeling HOC uptake by PE in aqueous systems. The model is an analytic solution to Fick's second law applied through an aqueous diffusive boundary layer and a polyethylene layer. Comparisons of the model with existing methods indicate agreement at appropriate boundary conditions. Laboratory release experiments on the organochlorine pesticides DDT, DDE, DDD, and chlordane in well-mixed slurries support the model's applicability to aqueous systems. In general, the advantage of the model is its application in the cases of well-agitated systems, low values of polyethylene-water partioning coefficients, thick polyethylene relative to the boundary layer thickness, and/or short exposure times. Another significant advantage is the ability to estimate, or at least bound, the needed exposure time to reach a desired CPE without empirical model inputs. A further finding of this work is that polyethylene diffusivity does not vary by transport direction through the sampler thickness.

  14. OBJECT ORIENTED MODELLING, A MODELLING METHOD OF AN ECONOMIC ORGANIZATION ACTIVITY

    Directory of Open Access Journals (Sweden)

    TĂNĂSESCU ANA

    2014-05-01

    Full Text Available Now, most economic organizations use different information systems types in order to facilitate their activity. There are different methodologies, methods and techniques that can be used to design information systems. In this paper, I propose to present the advantages of using the object oriented modelling at the information system design of an economic organization. Thus, I have modelled the activity of a photo studio, using Visual Paradigm for UML as a modelling tool. For this purpose, I have identified the use cases for the analyzed system and I have presented the use case diagram. I have, also, realized the system static and dynamic modelling, through the most known UML diagrams.

  15. Multiscale Modeling and Simulation of Organic Solar Cells

    CERN Document Server

    de Falco, Carlo; Sacco, Riccardo; Verri, Maurizio

    2012-01-01

    In this article, we continue our mathematical study of organic solar cells (OSCs) and propose a two-scale (micro- and macro-scale) model of heterojunction OSCs with interface geometries characterized by an arbitrarily complex morphology. The microscale model consists of a system of partial and ordinary differential equations in an heterogeneous domain, that provides a full description of excitation/transport phenomena occurring in the bulk regions and dissociation/recombination processes occurring in a thin material slab across the interface. The macroscale model is obtained by a micro-to-macro scale transition that consists of averaging the mass balance equations in the normal direction across the interface thickness, giving rise to nonlinear transmission conditions that are parametrized by the interfacial width. These conditions account in a lumped manner for the volumetric dissociation/recombination phenomena occurring in the thin slab and depend locally on the electric field magnitude and orientation. Usi...

  16. Controlling self-organized criticality in sandpile models

    CERN Document Server

    Cajueiro, Daniel O

    2013-01-01

    We introduce an external control to reduce the size of avalanches in some sandpile models exhibiting self organized criticality. This rather intuitive approach seems to be missing in the vast literature on such systems. The control action, which amounts to triggering avalanches in sites that are near to be come critical, reduces the probability of very large events, so that energy dissipation occurs most locally. The control is applied to a directed Abelian sandpile model driven by both uncorrelated and correlated deposition. The latter is essential to design an efficient and simple control heuristic, but has only small influence in the uncontrolled avalanche probability distribution. The proposed control seeks a tradeoff between control cost and large event risk. Preliminary results hint that the proposed control works also for an undirected sandpile model.

  17. Genome Editing and Its Applications in Model Organisms

    Directory of Open Access Journals (Sweden)

    Dongyuan Ma

    2015-12-01

    Full Text Available Technological advances are important for innovative biological research. Development of molecular tools for DNA manipulation, such as zinc finger nucleases (ZFNs, transcription activator-like effector nucleases (TALENs, and the clustered regularly-interspaced short palindromic repeat (CRISPR/CRISPR-associated (Cas, has revolutionized genome editing. These approaches can be used to develop potential therapeutic strategies to effectively treat heritable diseases. In the last few years, substantial progress has been made in CRISPR/Cas technology, including technical improvements and wide application in many model systems. This review describes recent advancements in genome editing with a particular focus on CRISPR/Cas, covering the underlying principles, technological optimization, and its application in zebrafish and other model organisms, disease modeling, and gene therapy used for personalized medicine.

  18. Intelligent Model for Measuring Organization Maturity in E-Business

    Directory of Open Access Journals (Sweden)

    Sadra Ahmadi

    2009-07-01

    Full Text Available E-Business is one of the most fascinating areas of information Technology. Managers should seek out means for making decision towards optimizing resource development in this area in order to control their expense and capital allocations at a higher, strategic level. To do this, manager must first identify their level of e-business development and plan to improve the status quo by identifying factors contributing to the growth in this approach. The present paper aims to construct and develop intelligent models for determining the organization status quo and management decision-making towards improving the situation using fuzzy [logic] tools. Thus for modeling these factors and their impact, the contributing factors in development of e-business approaches were identified by literature survey. These were later categorized using Delphi Method. Furthermore the FCM model was used to graphically illustrate the causal relationships among factors, including the mode and means of their mutual impact.

  19. Self-organized criticality model for brain plasticity.

    Science.gov (United States)

    de Arcangelis, Lucilla; Perrone-Capano, Carla; Herrmann, Hans J

    2006-01-20

    Networks of living neurons exhibit an avalanche mode of activity, experimentally found in organotypic cultures. Here we present a model that is based on self-organized criticality and takes into account brain plasticity, which is able to reproduce the spectrum of electroencephalograms (EEG). The model consists of an electrical network with threshold firing and activity-dependent synapse strengths. The system exhibits an avalanche activity in a power-law distribution. The analysis of the power spectra of the electrical signal reproduces very robustly the power-law behavior with the exponent 0.8, experimentally measured in EEG spectra. The same value of the exponent is found on small-world lattices and for leaky neurons, indicating that universality holds for a wide class of brain models.

  20. Genome Editing and Its Applications in Model Organisms.

    Science.gov (United States)

    Ma, Dongyuan; Liu, Feng

    2015-12-01

    Technological advances are important for innovative biological research. Development of molecular tools for DNA manipulation, such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and the clustered regularly-interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas), has revolutionized genome editing. These approaches can be used to develop potential therapeutic strategies to effectively treat heritable diseases. In the last few years, substantial progress has been made in CRISPR/Cas technology, including technical improvements and wide application in many model systems. This review describes recent advancements in genome editing with a particular focus on CRISPR/Cas, covering the underlying principles, technological optimization, and its application in zebrafish and other model organisms, disease modeling, and gene therapy used for personalized medicine.

  1. Model for Triplet State Engineering in Organic Light Emitting Diodes

    CERN Document Server

    Prodhan, Suryoday; Ramasesha, S

    2014-01-01

    Engineering the position of the lowest triplet state (T1) relative to the first excited singlet state (S1) is of great importance in improving the efficiencies of organic light emitting diodes and organic photovoltaic cells. We have carried out model exact calculations of substituted polyene chains to understand the factors that affect the energy gap between S1 and T1. The factors studied are backbone dimerisation, different donor-acceptor substitutions and twisted geometry. The largest system studied is an eighteen carbon polyene which spans a Hilbert space of about 991 million. We show that for reverse intersystem crossing (RISC) process, the best system involves substituting all carbon sites on one half of the polyene with donors and the other half with acceptors.

  2. Table of 3D organ model IDs and organ names (IS-A Tree) - BodyParts3D | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available List Contact us BodyParts3D Table of 3D organ model IDs and organ names (IS-A Tree) Data detail Data name Table of 3D organ model...ontents List of downloadable 3D organ models in a tab-delimited text file format, describing the correspondence between 3D organ mode...| Contact Us Table of 3D organ model IDs and organ names (IS-A Tree) - BodyParts3D | LSDB Archive ...

  3. Developing an Enzyme Mediated Soil Organic Carbon Decomposition Model

    Science.gov (United States)

    Mayes, M. A.; Post, W. M.; Wang, G.; Jagadamma, S.; Steinweg, J. M.; Schadt, C. W.

    2012-12-01

    We developed the Microbial-ENzyme-mediated Decomposition (MEND) model in order to mechanistically model the decomposition of soil organic carbon (C). This presentation is an overview of the concept and development of the model and of the design of complementary lab-scale experiments. The model divides soil C into five pools of particulate, mineral-associated, dissolved, microbial, and enzyme organic C (Wang et al. 2012). There are three input types - cellulose, lignin, and dissolved C. Decomposition is mediated via microbial extracellular enzymes using the Michaelis-Menten equation, resulting in the production of a common pool of dissolved organic C. Parameters for the Michaelis-Menten equation are obtained through a literature review (Wang and Post, 2012a). The dissolved C is taken up by microbial biomass and proportioned according to microbial maintenance and growth, which were recalculated according to Wang and Post (2012b). The model allows dissolved C to undergo adsorption and desorption reactions with the mineral-associated C, which was also parameterized based upon a literature review and complementary laboratory experiments. In the lab, four 14C-labeled substrates (cellulose, fatty acid, glucose, and lignin-like) were incubated with either the particulate C pool, the mineral-associated C pool, or to bulk soils. The rate of decomposition was measured via the production of 14CO2 over time, along with incorporation into microbial biomass, production of dissolved C, and estimation of sorbed C. We performed steady-state and dynamic simulations and sensitivity analyses under temperature increases of 1-5°C for a period of 100 y. Simulations indicated an initial decrease in soil organic C consisting of both cellulose and lignin pools. Over longer time intervals (> 6 y), however, a shrinking microbial population, a concomitant decrease in enzyme production, and a decrease in microbial carbon use efficiency together decreased CO2 production and resulted in greater

  4. Thermodynamic Modeling of Organic-Inorganic Aerosols with the Group-Contribution Model AIOMFAC

    Science.gov (United States)

    Zuend, A.; Marcolli, C.; Luo, B. P.; Peter, T.

    2009-04-01

    Liquid aerosol particles are - from a physicochemical viewpoint - mixtures of inorganic salts, acids, water and a large variety of organic compounds (Rogge et al., 1993; Zhang et al., 2007). Molecular interactions between these aerosol components lead to deviations from ideal thermodynamic behavior. Strong non-ideality between organics and dissolved ions may influence the aerosol phases at equilibrium by means of liquid-liquid phase separations into a mainly polar (aqueous) and a less polar (organic) phase. A number of activity models exists to successfully describe the thermodynamic equilibrium of aqueous electrolyte solutions. However, the large number of different, often multi-functional, organic compounds in mixed organic-inorganic particles is a challenging problem for the development of thermodynamic models. The group-contribution concept as introduced in the UNIFAC model by Fredenslund et al. (1975), is a practical method to handle this difficulty and to add a certain predictability for unknown organic substances. We present the group-contribution model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients), which explicitly accounts for molecular interactions between solution constituents, both organic and inorganic, to calculate activities, chemical potentials and the total Gibbs energy of mixed systems (Zuend et al., 2008). This model enables the computation of vapor-liquid (VLE), liquid-liquid (LLE) and solid-liquid (SLE) equilibria within one framework. Focusing on atmospheric applications we considered eight different cations, five anions and a wide range of alcohols/polyols as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are very well represented up to high ionic strength. We show that the semi-empirical middle-range parametrization of direct organic-inorganic interactions in alcohol-water-salt solutions enables accurate computations of vapor-liquid and liquid

  5. Contemporary model of language organization: an overview for neurosurgeons.

    Science.gov (United States)

    Chang, Edward F; Raygor, Kunal P; Berger, Mitchel S

    2015-02-01

    Classic models of language organization posited that separate motor and sensory language foci existed in the inferior frontal gyrus (Broca's area) and superior temporal gyrus (Wernicke's area), respectively, and that connections between these sites (arcuate fasciculus) allowed for auditory-motor interaction. These theories have predominated for more than a century, but advances in neuroimaging and stimulation mapping have provided a more detailed description of the functional neuroanatomy of language. New insights have shaped modern network-based models of speech processing composed of parallel and interconnected streams involving both cortical and subcortical areas. Recent models emphasize processing in "dorsal" and "ventral" pathways, mediating phonological and semantic processing, respectively. Phonological processing occurs along a dorsal pathway, from the posterosuperior temporal to the inferior frontal cortices. On the other hand, semantic information is carried in a ventral pathway that runs from the temporal pole to the basal occipitotemporal cortex, with anterior connections. Functional MRI has poor positive predictive value in determining critical language sites and should only be used as an adjunct for preoperative planning. Cortical and subcortical mapping should be used to define functional resection boundaries in eloquent areas and remains the clinical gold standard. In tracing the historical advancements in our understanding of speech processing, the authors hope to not only provide practicing neurosurgeons with additional information that will aid in surgical planning and prevent postoperative morbidity, but also underscore the fact that neurosurgeons are in a unique position to further advance our understanding of the anatomy and functional organization of language.

  6. Performance Evaluation Based on EFQM Excellence Model in Sport Organizations

    Directory of Open Access Journals (Sweden)

    Rasoul Faraji

    2012-06-01

    Full Text Available The present study aims to evaluate the performance of physical education (P.E. general office of Tehran province through model of European Foundation for Quality Management (EFQM. Questionnaire approach was used in this study. Therefore validity of the 50-item EFQM questionnaire verified by the experts and the reliability also calculated in a pilot study (α=0.928. 95 questionnaires distributed between subjects (N=n and 80 questionnaires returned and concluded in the statistical analysis. From nine EFQM criteria, the highest scores were gained in key performance results (37.62% and the lowest gained in people results (27.94%. Totally, this organization achieved 337.11 pointes out of a total of 1000. Additionally, there was a strong relationship (r=0.827, p=0.001 between enablers and results (P<0.05. Based on scores gained in the criteria, improving measures in all criteria is essential for this organization, especially in the people criterion from enablers and people results criterion from results domain. Furthermore, it is believed that the physical education area is one of the best fields for application of the excellence model towards the performance excellence and gaining better results and hence, it seems that the model has a high potential in responding to problems commonly seen in sport sector.

  7. Modeling of secondary organic aerosol yields from laboratory chamber data

    Directory of Open Access Journals (Sweden)

    M. N. Chan

    2009-04-01

    Full Text Available A product-specific model for secondary organic aerosol (SOA formation and composition based on equilibrium gas-particle partitioning is evaluated. The model is applied to represent laboratory data on the ozonolysis of α-pinene under dry, dark, and low-NOx conditions in the presence of ammonium sulfate seed aerosol. Using five major identified products, the model is fit to the chamber data. From the optimal fitting, SOA oxygen-to-carbon (O/C and hydrogen-to-carbon (H/C ratios are modeled. The discrepancy between measured H/C ratios and those based on the oxidation products used in the model fitting suggests the potential importance of particle-phase reactions. Data fitting is also carried out using the volatility basis set, wherein oxidation products are parsed into volatility bins. The product-specific model is best used for an SOA precursor for which a substantial fraction of the aerosol-phase oxidation products has been identified.

  8. A Revised Iranian Model of Organ Donation as an Answer to the Current Organ Shortage Crisis.

    Science.gov (United States)

    Hamidian Jahromi, Alireza; Fry-Revere, Sigrid; Bastani, Bahar

    2015-09-01

    Kidney transplantation has become the treatment of choice for patients with end-stage renal disease. Six decades of success in the field of transplantation have made it possible to save thousands of lives every year. Unfortunately, in recent years success has been overshadowed by an ever-growing shortage of organs. In the United States, there are currently more than 100 000 patients waiting for kidneys. However, the supply of kidneys (combined cadaveric and live donations) has stagnated around 17 000 per year. The ever-widening gap between demand and supply has resulted in an illegal black market and unethical transplant tourism of global proportions. While we believe there is much room to improve the Iranian model of regulated incentivized live kidney donation, with some significant revisions, the Iranian Model could serve as an example for how other countries could make significant strides to lessening their own organ shortage crises.

  9. Modeling the role of microplastics in Bioaccumulation of organic chemicals to marine aquatic organisms. Critical Review

    NARCIS (Netherlands)

    Koelmans, A.A.

    2015-01-01

    It has been shown that ingestion of microplastics may increase bioaccumulation of organic chemicals by aquatic organisms. This paper critically reviews the literature on the effects of plastic ingestion on the bioaccumulation of organic chemicals, emphasizing quantitative approaches and mechanistic

  10. Modeling the adsorption of weak organic acids on goethite: the ligand and charge distribution model

    NARCIS (Netherlands)

    Filius, J.D.

    2001-01-01

    A detailed study is presented in which the CD-MUSIC modeling approach is used in a new modeling approach that can describe the binding of large organic molecules by metal (hydr)oxides taking the full speciation of the adsorbed molecule into account. Batch equilibration experiments were performed usi

  11. Generic Modelling of Faecal Indicator Organism Concentrations in the UK

    Directory of Open Access Journals (Sweden)

    Carl M. Stapleton

    2011-06-01

    Full Text Available To meet European Water Framework Directive requirements, data are needed on faecal indicator organism (FIO concentrations in rivers to enable the more heavily polluted to be targeted for remedial action. Due to the paucity of FIO data for the UK, especially under high-flow hydrograph event conditions, there is an urgent need by the policy community for generic models that can accurately predict FIO concentrations, thus informing integrated catchment management programmes. This paper reports the development of regression models to predict base- and high-flow faecal coliform (FC and enterococci (EN concentrations for 153 monitoring points across 14 UK catchments, using land cover, population (human and livestock density and other variables that may affect FIO source strength, transport and die-off. Statistically significant models were developed for both FC and EN, with greater explained variance achieved in the high-flow models. Both land cover and, in particular, population variables are significant predictors of FIO concentrations, with r2 maxima for EN of 0.571 and 0.624, respectively. It is argued that the resulting models can be applied, with confidence, to other UK catchments, both to predict FIO concentrations in unmonitored watercourses and evaluate the likely impact of different land use/stocking level and human population change scenarios.

  12. Modeling financial markets by self-organized criticality

    Science.gov (United States)

    Biondo, Alessio Emanuele; Pluchino, Alessandro; Rapisarda, Andrea

    2015-10-01

    We present a financial market model, characterized by self-organized criticality, that is able to generate endogenously a realistic price dynamics and to reproduce well-known stylized facts. We consider a community of heterogeneous traders, composed by chartists and fundamentalists, and focus on the role of informative pressure on market participants, showing how the spreading of information, based on a realistic imitative behavior, drives contagion and causes market fragility. In this model imitation is not intended as a change in the agent's group of origin, but is referred only to the price formation process. We introduce in the community also a variable number of random traders in order to study their possible beneficial role in stabilizing the market, as found in other studies. Finally, we also suggest some counterintuitive policy strategies able to dampen fluctuations by means of a partial reduction of information.

  13. Modeling financial markets by self-organized criticality.

    Science.gov (United States)

    Biondo, Alessio Emanuele; Pluchino, Alessandro; Rapisarda, Andrea

    2015-10-01

    We present a financial market model, characterized by self-organized criticality, that is able to generate endogenously a realistic price dynamics and to reproduce well-known stylized facts. We consider a community of heterogeneous traders, composed by chartists and fundamentalists, and focus on the role of informative pressure on market participants, showing how the spreading of information, based on a realistic imitative behavior, drives contagion and causes market fragility. In this model imitation is not intended as a change in the agent's group of origin, but is referred only to the price formation process. We introduce in the community also a variable number of random traders in order to study their possible beneficial role in stabilizing the market, as found in other studies. Finally, we also suggest some counterintuitive policy strategies able to dampen fluctuations by means of a partial reduction of information.

  14. Modelling Financial Markets by Self-Organized Criticality

    CERN Document Server

    Biondo, A E; Rapisarda, A

    2015-01-01

    We present a financial market model, characterized by self-organized criticality, that is able to generate endogenously a realistic price dynamics and to reproduce well-known stylized facts. We consider a community of heterogeneous traders, composed by chartists and fundamentalists, and focus on the role of informative pressure on market participants, showing how the spreading of information, based on a realistic imitative behavior, drives contagion and causes market fragility. In this model imitation is not intended as a change in the agent's group of origin, but is referred only to the price formation process. We introduce in the community also a variable number of random traders in order to study their possible beneficial role in stabilizing the market, as found in other studies. Finally we also suggest some counterintuitive policy strategies able to dampen fluctuations by means of a partial reduction of information.

  15. Partitioning of Nanoparticles into Organic Phases and Model Cells

    Energy Technology Data Exchange (ETDEWEB)

    Posner, J.D.; Westerhoff, P.; Hou, W-C.

    2011-08-25

    There is a recognized need to understand and predict the fate, transport and bioavailability of engineered nanoparticles (ENPs) in aquatic and soil ecosystems. Recent research focuses on either collection of empirical data (e.g., removal of a specific NP through water or soil matrices under variable experimental conditions) or precise NP characterization (e.g. size, degree of aggregation, morphology, zeta potential, purity, surface chemistry, and stability). However, it is almost impossible to transition from these precise measurements to models suitable to assess the NP behavior in the environment with complex and heterogeneous matrices. For decades, the USEPA has developed and applies basic partitioning parameters (e.g., octanol-water partition coefficients) and models (e.g., EPI Suite, ECOSAR) to predict the environmental fate, bioavailability, and toxicity of organic pollutants (e.g., pesticides, hydrocarbons, etc.). In this project we have investigated the hypothesis that NP partition coefficients between water and organic phases (octanol or lipid bilayer) is highly dependent on their physiochemical properties, aggregation, and presence of natural constituents in aquatic environments (salts, natural organic matter), which may impact their partitioning into biological matrices (bioaccumulation) and human exposure (bioavailability) as well as the eventual usage in modeling the fate and bioavailability of ENPs. In this report, we use the terminology "partitioning" to operationally define the fraction of ENPs distributed among different phases. The mechanisms leading to this partitioning probably involve both chemical force interactions (hydrophobic association, hydrogen bonding, ligand exchange, etc.) and physical forces that bring the ENPs in close contact with the phase interfaces (diffusion, electrostatic interactions, mixing turbulence, etc.). Our work focuses on partitioning, but also provides insight into the relative behavior of ENPs as either "more like

  16. Partitioning of Nanoparticles into Organic Phases and Model Cells

    Energy Technology Data Exchange (ETDEWEB)

    Posner, J.D.; Westerhoff, P.; Hou, W-C.

    2011-08-25

    There is a recognized need to understand and predict the fate, transport and bioavailability of engineered nanoparticles (ENPs) in aquatic and soil ecosystems. Recent research focuses on either collection of empirical data (e.g., removal of a specific NP through water or soil matrices under variable experimental conditions) or precise NP characterization (e.g. size, degree of aggregation, morphology, zeta potential, purity, surface chemistry, and stability). However, it is almost impossible to transition from these precise measurements to models suitable to assess the NP behavior in the environment with complex and heterogeneous matrices. For decades, the USEPA has developed and applies basic partitioning parameters (e.g., octanol-water partition coefficients) and models (e.g., EPI Suite, ECOSAR) to predict the environmental fate, bioavailability, and toxicity of organic pollutants (e.g., pesticides, hydrocarbons, etc.). In this project we have investigated the hypothesis that NP partition coefficients between water and organic phases (octanol or lipid bilayer) is highly dependent on their physiochemical properties, aggregation, and presence of natural constituents in aquatic environments (salts, natural organic matter), which may impact their partitioning into biological matrices (bioaccumulation) and human exposure (bioavailability) as well as the eventual usage in modeling the fate and bioavailability of ENPs. In this report, we use the terminology "partitioning" to operationally define the fraction of ENPs distributed among different phases. The mechanisms leading to this partitioning probably involve both chemical force interactions (hydrophobic association, hydrogen bonding, ligand exchange, etc.) and physical forces that bring the ENPs in close contact with the phase interfaces (diffusion, electrostatic interactions, mixing turbulence, etc.). Our work focuses on partitioning, but also provides insight into the relative behavior of ENPs as either "more like

  17. Correlated earthquakes in a self-organized model

    Directory of Open Access Journals (Sweden)

    M. Baiesi

    2009-03-01

    Full Text Available Motivated by the fact that empirical time series of earthquakes exhibit long-range correlations in space and time and the Gutenberg-Richter distribution of magnitudes, we propose a simple fault model that can account for these types of scale-invariance. It is an avalanching process that displays power-laws in the event sizes, in the epicenter distances as well as in the waiting-time distributions, and also aftershock rates obeying a generalized Omori law. We thus confirm that there is a relation between temporal and spatial clustering of the activity in this kind of models. The fluctuating boundaries of possible slipping areas show that the size of the largest possible earthquake is not always maximal, and the average correlation length is a fraction of the system size. This suggests that there is a concrete alternative to the extreme interpretation of self-organized criticality as a process in which every small event can cascade to an arbitrary large one: the new picture includes fluctuating domains of coherent stress field as part of the global self-organization. Moreover, this picture can be more easily compared with other scenarios discussing fluctuating correlations lengths in seismicity.

  18. Terrestrial and marine perspectives on modeling organic matter degradation pathways.

    Science.gov (United States)

    Burd, Adrian B; Frey, Serita; Cabre, Anna; Ito, Takamitsu; Levine, Naomi M; Lønborg, Christian; Long, Matthew; Mauritz, Marguerite; Thomas, R Quinn; Stephens, Brandon M; Vanwalleghem, Tom; Zeng, Ning

    2016-01-01

    Organic matter (OM) plays a major role in both terrestrial and oceanic biogeochemical cycles. The amount of carbon stored in these systems is far greater than that of carbon dioxide (CO2 ) in the atmosphere, and annual fluxes of CO2 from these pools to the atmosphere exceed those from fossil fuel combustion. Understanding the processes that determine the fate of detrital material is important for predicting the effects that climate change will have on feedbacks to the global carbon cycle. However, Earth System Models (ESMs) typically utilize very simple formulations of processes affecting the mineralization and storage of detrital OM. Recent changes in our view of the nature of this material and the factors controlling its transformation have yet to find their way into models. In this review, we highlight the current understanding of the role and cycling of detrital OM in terrestrial and marine systems and examine how this pool of material is represented in ESMs. We include a discussion of the different mineralization pathways available as organic matter moves from soils, through inland waters to coastal systems and ultimately into open ocean environments. We argue that there is strong commonality between aspects of OM transformation in both terrestrial and marine systems and that our respective scientific communities would benefit from closer collaboration.

  19. Modeling organic micro pollutant degradation kinetics during sewage sludge composting.

    Science.gov (United States)

    Sadef, Yumna; Poulsen, Tjalfe Gorm; Bester, Kai

    2014-11-01

    Degradation of 13 different organic micro-pollutants in sewage sludge during aerobic composting at 5 different temperatures over a 52 day period was investigated. Adequacy of two kinetic models: a single first order, and a dual first order expression (using an early (first 7 days) and a late-time (last 45 days) degradation coefficient), for describing micro-pollutant degradation, and kinetic constant dependency on composting temperature were evaluated. The results showed that both models provide relatively good descriptions of the degradation process, with the dual first order model being most accurate. The single first order degradation coefficient was 0.025 d(-1) on average across all compounds and temperatures. At early times, degradation was about three times faster than at later times. Average values of the early and late time degradation coefficients for the dual first order model were 0.066 d(-1) and 0.022 d(-1), respectively. On average 30% of the initial micro-pollutant mass present in the compost was degraded rapidly during the early stages of the composting process. Single first order and late time dual first order kinetic constants were strongly dependent on composting temperature with maximum values at temperatures of 35-65°C. In contrast the early time degradation coefficients were relatively independent of composting temperature.

  20. Mathematical modeling of wastewater-derived biodegradable dissolved organic nitrogen.

    Science.gov (United States)

    Simsek, Halis

    2016-11-01

    Wastewater-derived dissolved organic nitrogen (DON) typically constitutes the majority of total dissolved nitrogen (TDN) discharged to surface waters from advanced wastewater treatment plants (WWTPs). When considering the stringent regulations on nitrogen discharge limits in sensitive receiving waters, DON becomes problematic and needs to be reduced. Biodegradable DON (BDON) is a portion of DON that is biologically degradable by bacteria when the optimum environmental conditions are met. BDON in a two-stage trickling filter WWTP was estimated using artificial intelligence techniques, such as adaptive neuro-fuzzy inference systems, multilayer perceptron, radial basis neural networks (RBNN), and generalized regression neural networks. Nitrite, nitrate, ammonium, TDN, and DON data were used as input neurons. Wastewater samples were collected from four different locations in the plant. Model performances were evaluated using root mean square error, mean absolute error, mean bias error, and coefficient of determination statistics. Modeling results showed that the R(2) values were higher than 0.85 in all four models for all wastewater samples, except only R(2) in the final effluent sample for RBNN modeling was low (0.52). Overall, it was found that all four computing techniques could be employed successfully to predict BDON.

  1. Priming and substrate quality interactions in soil organic matter models

    Directory of Open Access Journals (Sweden)

    T. Wutzler

    2012-12-01

    Full Text Available Interactions between different qualities of soil organic matter (SOM affecting their turnover are rarely represented in models. In this study we propose three mathematical strategies at different levels of abstraction for representing those interactions. Implementing these strategies into the Introductory Carbon Balance Model (ICBM and applying them to several scenarios of litter input show that the different levels of abstraction are applicable on different time scales. We present a simple one-parameter equation of substrate limitation applicable at decadal time scale that is straightforward to implement into other models of SOM dynamics. We show how substrate quality interactions can explain priming effects, acceleration of turnover times in FACE experiments, and the slowdown of decomposition in long-term bare fallow experiments as an effect of energy limitation of microbial biomass. The mechanisms of those interactions need to be further scrutinized empirically for a more complete understanding. Overall, substrate quality interactions offer a valuable way of understanding and quantitatively modelling SOM dynamics.

  2. Modeling organic aerosols during MILAGRO: importance of biogenic secondary organic aerosols

    Directory of Open Access Journals (Sweden)

    A. Hodzic

    2009-09-01

    Full Text Available The meso-scale chemistry-transport model CHIMERE is used to assess our understanding of major sources and formation processes leading to a fairly large amount of organic aerosols – OA, including primary OA (POA and secondary OA (SOA – observed in Mexico City during the MILAGRO field project (March 2006. Chemical analyses of submicron aerosols from aerosol mass spectrometers (AMS indicate that organic particles found in the Mexico City basin contain a large fraction of oxygenated organic species (OOA which have strong correspondence with SOA, and that their production actively continues downwind of the city. The SOA formation is modeled here by the one-step oxidation of anthropogenic (i.e. aromatics, alkanes, biogenic (i.e. monoterpenes and isoprene, and biomass-burning SOA precursors and their partitioning into both organic and aqueous phases. Conservative assumptions are made for uncertain parameters to maximize the amount of SOA produced by the model. The near-surface model evaluation shows that predicted OA correlates reasonably well with measurements during the campaign, however it remains a factor of 2 lower than the measured total OA. Fairly good agreement is found between predicted and observed POA within the city suggesting that anthropogenic and biomass burning emissions are reasonably captured. Consistent with previous studies in Mexico City, large discrepancies are encountered for SOA, with a factor of 2–10 model underestimate. When only anthropogenic SOA precursors were considered, the model was able to reproduce within a factor of two the sharp increase in OOA concentrations during the late morning at both urban and near-urban locations but the discrepancy increases rapidly later in the day, consistent with previous results, and is especially obvious when the column-integrated SOA mass is considered instead of the surface concentration. The increase in the missing SOA mass in the afternoon coincides with the sharp drop in POA

  3. Modeling biogenic and anthropogenic secondary organic aerosol in China

    Science.gov (United States)

    Hu, Jianlin; Wang, Peng; Ying, Qi; Zhang, Hongliang; Chen, Jianjun; Ge, Xinlei; Li, Xinghua; Jiang, Jingkun; Wang, Shuxiao; Zhang, Jie; Zhao, Yu; Zhang, Yingyi

    2017-01-01

    A revised Community Multi-scale Air Quality (CMAQ) model with updated secondary organic aerosol (SOA) yields and a more detailed description of SOA formation from isoprene oxidation was applied to study the spatial and temporal distribution of SOA in China in the entire year of 2013. Predicted organic carbon (OC), elemental carbon and volatile organic compounds agreed favorably with observations at several urban areas, although the high OC concentrations in wintertime in Beijing were under-predicted. Predicted summer SOA was generally higher (10-15 µg m-3) due to large contributions of isoprene (country average, 61 %), although the relative importance varies in different regions. Winter SOA was slightly lower and was mostly due to emissions of alkane and aromatic compounds (51 %). Contributions of monoterpene SOA was relatively constant (8-10 %). Overall, biogenic SOA accounted for approximately 75 % of total SOA in summer, 50-60 % in autumn and spring, and 24 % in winter. The Sichuan Basin had the highest predicted SOA concentrations in the country in all seasons, with hourly concentrations up to 50 µg m-3. Approximately half of the SOA in all seasons was due to the traditional equilibrium partitioning of semivolatile components followed by oligomerization, while the remaining SOA was mainly due to reactive surface uptake of isoprene epoxide (5-14 %), glyoxal (14-25 %) and methylglyoxal (23-28 %). Sensitivity analyses showed that formation of SOA from biogenic emissions was significantly enhanced due to anthropogenic emissions. Removing all anthropogenic emissions while keeping the biogenic emissions unchanged led to total SOA concentrations of less than 1 µg m-3, which suggests that manmade emissions facilitated biogenic SOA formation and controlling anthropogenic emissions would result in reduction of both anthropogenic and biogenic SOA.

  4. Nephrology around Europe: organization models and management strategies: Spain.

    Science.gov (United States)

    de Francisco, Angel L M; Piñera, Celestino

    2011-01-01

    The main aim of this report is to present a picture of the current organization of nephrology in Spain. The Spanish health system offers almost universal coverage, a wide variety of services and a high-quality network of hospitals and primary care centers. Spain has a specialized health care training system that is highly developed, highly regulated, with the capacity to provide high-quality training in 54 different specialties. Nephrology is basically a hospital-based specialty. There are no private dialysis patients in Spain. Hemodialysis centers are 40% public, 15% private and 45% run by companies. The National Health System covers 95% of the population, and there is no cost to patients for treatment of renal disease (dialysis and transplant). We observed a clear decrease of nephrology in residents' election rankings, with position 29 out of 47 specialties in 2007. Some of the reasons for this are the complexity of the subject, no clear information at the university, reduction of professional posts and a very good public service with minimal private practice. In Spain, a model of organization for transplantation was adopted based on a decentralized transplant coordinating network. For cadaveric donors, it compares favorably with rates in other Western countries. Living donor transplantation is very low in Spain--just 10% of total renal transplantation activity. New programs due to financial constraints need to include reduced dialysis costs, greater cost-effectiveness of prescriptions, better handling of ethical issues related to the need for using a clinical score of chronic kidney disease patients to make decisions about conservative or renal replacement therapy and an action plan for improvement of organ donation and transplantation. Recovery of skills (acute kidney injury, biopsies, vascular access, etc.), research and advances in autonomous activities (imaging, surgical and medical vascular training, etc.) are some of the future educational paths needed in

  5. Modeling evolutionary dynamics of epigenetic mutations in hierarchically organized tumors.

    Directory of Open Access Journals (Sweden)

    Andrea Sottoriva

    2011-05-01

    Full Text Available The cancer stem cell (CSC concept is a highly debated topic in cancer research. While experimental evidence in favor of the cancer stem cell theory is apparently abundant, the results are often criticized as being difficult to interpret. An important reason for this is that most experimental data that support this model rely on transplantation studies. In this study we use a novel cellular Potts model to elucidate the dynamics of established malignancies that are driven by a small subset of CSCs. Our results demonstrate that epigenetic mutations that occur during mitosis display highly altered dynamics in CSC-driven malignancies compared to a classical, non-hierarchical model of growth. In particular, the heterogeneity observed in CSC-driven tumors is considerably higher. We speculate that this feature could be used in combination with epigenetic (methylation sequencing studies of human malignancies to prove or refute the CSC hypothesis in established tumors without the need for transplantation. Moreover our tumor growth simulations indicate that CSC-driven tumors display evolutionary features that can be considered beneficial during tumor progression. Besides an increased heterogeneity they also exhibit properties that allow the escape of clones from local fitness peaks. This leads to more aggressive phenotypes in the long run and makes the neoplasm more adaptable to stringent selective forces such as cancer treatment. Indeed when therapy is applied the clone landscape of the regrown tumor is more aggressive with respect to the primary tumor, whereas the classical model demonstrated similar patterns before and after therapy. Understanding these often counter-intuitive fundamental properties of (non-hierarchically organized malignancies is a crucial step in validating the CSC concept as well as providing insight into the therapeutical consequences of this model.

  6. Spectrophotometry and organic matter on Iapetus. 1: Composition models

    Science.gov (United States)

    Wilson, Peter D.; Sagan, Carl

    1995-01-01

    Iapetus shows a greater hemispheric albedo asymmetry than any other body in the solar system. Hapke scattering theory and optical constants measured in the laboratory are used to identify possible compositions for the dark material on the leading hemisphere of Iapetus. The materials considered are poly-HCN, kerogen, Murchison organic residue, Titan tholin, ice tholin, and water ice. Three-component mixtures of these materials are modeled in intraparticle mixture of 25% poly-HCN, 10% Murchison residue, and 65% water ice is found to best fit the spectrum, albedo, and phase behavior of the dark material. The Murchison residue and/or water ice can be replaced by kerogen and ice tholin, respectively, and still produce very good fits. Areal and particle mixtures of poly-HCN, Titan tholin, and either ice tholin or Murchison residue are also possible models. Poly-HCN is a necessary component in almost all good models. The presence of poly-HCN can be further tested by high-resolution observations near 4.5 micrometers.

  7. In Vivo RNAi-Based Screens: Studies in Model Organisms

    Directory of Open Access Journals (Sweden)

    Miki Yamamoto-Hino

    2013-11-01

    Full Text Available RNA interference (RNAi is a technique widely used for gene silencing in organisms and cultured cells, and depends on sequence homology between double-stranded RNA (dsRNA and target mRNA molecules. Numerous cell-based genome-wide screens have successfully identified novel genes involved in various biological processes, including signal transduction, cell viability/death, and cell morphology. However, cell-based screens cannot address cellular processes such as development, behavior, and immunity. Drosophila and Caenorhabditis elegans are two model organisms whose whole bodies and individual body parts have been subjected to RNAi-based genome-wide screening. Moreover, Drosophila RNAi allows the manipulation of gene function in a spatiotemporal manner when it is implemented using the Gal4/UAS system. Using this inducible RNAi technique, various large-scale screens have been performed in Drosophila, demonstrating that the method is straightforward and valuable. However, accumulated results reveal that the results of RNAi-based screens have relatively high levels of error, such as false positives and negatives. Here, we review in vivo RNAi screens in Drosophila and the methods that could be used to remove ambiguity from screening results.

  8. Multiscale modelling of charge transport in organic electronic materials

    Science.gov (United States)

    Nelson, Jenny

    2010-03-01

    Charge transport in disordered organic semiconductors is controlled by a complex combination of phenomena that span a range of length and time scales. As a result, it is difficult to rationalize charge transport properties in terms of material parameters. Until now, efforts to improve charge mobilities in molecular semiconductors have proceeded largely by trial and error rather than through systematic design. However, recent developments have enabled the first predictive simulation studies of charge transport in disordered organic semiconductors. In this presentation we will show how a set of computational methods, namely molecular modelling methods to simulate molecular packing, quantum chemical calculations of charge transfer rates, and Monte Carlo simulations of charge transport can be used to reproduce experimental charge mobilities with few or no fitting parameters. Using case studies, we will show how such simulations can explain the relative values of electron and hole mobility and the effects of grain size, side chains and polymer molecular weight on charge mobility. Although currently applied to material systems of relatively high symmetry or well defined structure, this approach can be developed to address more complex systems such as multicomponent solids and conjugated polymers.

  9. EcoCyc: fusing model organism databases with systems biology.

    Science.gov (United States)

    Keseler, Ingrid M; Mackie, Amanda; Peralta-Gil, Martin; Santos-Zavaleta, Alberto; Gama-Castro, Socorro; Bonavides-Martínez, César; Fulcher, Carol; Huerta, Araceli M; Kothari, Anamika; Krummenacker, Markus; Latendresse, Mario; Muñiz-Rascado, Luis; Ong, Quang; Paley, Suzanne; Schröder, Imke; Shearer, Alexander G; Subhraveti, Pallavi; Travers, Mike; Weerasinghe, Deepika; Weiss, Verena; Collado-Vides, Julio; Gunsalus, Robert P; Paulsen, Ian; Karp, Peter D

    2013-01-01

    EcoCyc (http://EcoCyc.org) is a model organism database built on the genome sequence of Escherichia coli K-12 MG1655. Expert manual curation of the functions of individual E. coli gene products in EcoCyc has been based on information found in the experimental literature for E. coli K-12-derived strains. Updates to EcoCyc content continue to improve the comprehensive picture of E. coli biology. The utility of EcoCyc is enhanced by new tools available on the EcoCyc web site, and the development of EcoCyc as a teaching tool is increasing the impact of the knowledge collected in EcoCyc.

  10. A self-organized critical model for evolution

    Energy Technology Data Exchange (ETDEWEB)

    Flyvbjerg, H.; Bak, P.; Jensen, M.H.; Sneppen, K.

    1996-01-01

    A simple mathematical model of biological macroevolution is presented. It describes an ecology of adapting, interacting species. Species evolve to maximize their individual fitness in their environment. The environment of any given species is affected by other evolving species; hence it is not constant in time. The ecology evolves to a ``self-organized critical`` state where periods of stasis alternate with avalanches of causally connected evolutionary changes. This characteristic intermittent behaviour of natural history, known as ``punctuated equilibrium,`` thus finds a theoretical explanation as a selforganized critical phenomenon. In particular, large bursts of apparently simultaneous evolutionary activity require no external cause. They occur as the less frequent result of the very same dynamics that governs the more frequent small-scale evolutionary activity. Our results are compared with data from the fossil record collected by J. Sepkoski, Jr., and others.

  11. Modeling nanostructure-enhanced light trapping in organic solar cells

    DEFF Research Database (Denmark)

    Adam, Jost

    A promising approach for improving the power conversion efficiencies of organic solar cells (OSCs) is by incorporating nanostructures in their thin film architecture to improve the light absorption in the device’s active polymer layers. Here, we present a modelling framework for the prediction...... of optical and plasmonic field enhancement by nanostructures in (or close to) the active layers and electrodes in OSCs. We incorporate finite-difference time-domain (FDTD) calculations alongside semi- analytical approaches, as the rigorous coupled-wave analysis (RCWA) and mode-coupling theory. Our simulation......-compatible method for non-periodic electrode structuring by pores of controlled dimensions, formed through anodic oxidation of sputter-deposited high-purity aluminium films [3]. [1] Kluge, C., et al. Multi-periodic nanostructures for photon control. Optics Express, 22 (S5), A1363. (2014) [2] Skigin, D., et al...

  12. Corporate Social Responsibility And Islamic Business Organizations: A Proposed Model

    Directory of Open Access Journals (Sweden)

    Rusnah Muhamad

    2008-01-01

    Full Text Available The issue of corporate social responsibility (CSR has been of growing concern among business communities in recent years. Various corporate leaders maintain that business is considered to contribute fully to the society if it is effi cient, profi table and socially responsible. Islam is considered as addin (a way of life, thus, providing comprehensive guidelines in every aspects of the believers’ life. It is the aim of this paper to propose an Islamic model of corporate social responsibility based on human relationships with the God (hablun min’Allah; with other fellow human being (hablun min’an-nas and with the environment.Keywords : Corporate Social Responsibility, Islamic Business Organization

  13. Azolla - A Model Organism for Plant Genomic Studies

    Institute of Scientific and Technical Information of China (English)

    Yin-Long Qiu; Jun Yu

    2003-01-01

    The aquatic ferns of the genus Azolla are nitrogen-fixing plants that have great potentials in agricultural production and environmental conservation. Azolla in many aspects is qualified to serve as a model organism for genomic studies because of its importance in agriculture, its unique position in plant evolution, its symbiotic relationship with the N2-fixing cyanobacterium, Anabaena azollae, and its moderate-sized genome. The goals of this genome project are not only to understand the biology of the Azolla genome to promote its applications in biological research and agriculture practice but also to gain critical insights about evolution of plant genomes. Together with the strategic and technical improvement as well as cost reduction of DNA sequencing, the deciphering of their genetic code is imminent.

  14. Azolla—A Model Organism for Plant Genomic Studies

    Institute of Scientific and Technical Information of China (English)

    Yin-LongQiu; JunYu

    2003-01-01

    The aquatic ferns of the genus Azolla are nitrogen-fixing plants that have great potentials in agricultural production and environmental conservation.Azolla in many aspects is qualified to serve as a model organism for genomic studies because of its importance in agriculture,its unique position in plant evolution,its symbiotic relationship with the N2-fixing cyanobacterium,Anabaena azollae,and its moderate-sized genome.The goals of this genome project are not only to understand the biology of the Azolla genome to promote its applications in biological research and agriculture practice but also to gain critical insights about evolution of plant genomes.Together with the strategic and technical improvement as well as cost reduction of DNA sequencing,the deciphering of their genetic code is imminent.

  15. Giant plasma membrane vesicles: models for understanding membrane organization.

    Science.gov (United States)

    Levental, Kandice R; Levental, Ilya

    2015-01-01

    The organization of eukaryotic membranes into functional domains continues to fascinate and puzzle cell biologists and biophysicists. The lipid raft hypothesis proposes that collective lipid interactions compartmentalize the membrane into coexisting liquid domains that are central to membrane physiology. This hypothesis has proven controversial because such structures cannot be directly visualized in live cells by light microscopy. The recent observations of liquid-liquid phase separation in biological membranes are an important validation of the raft hypothesis and enable application of the experimental toolbox of membrane physics to a biologically complex phase-separated membrane. This review addresses the role of giant plasma membrane vesicles (GPMVs) in refining the raft hypothesis and expands on the application of GPMVs as an experimental model to answer some of key outstanding problems in membrane biology. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Self-organized criticality in a computer network model

    Science.gov (United States)

    Yuan; Ren; Shan

    2000-02-01

    We study the collective behavior of computer network nodes by using a cellular automaton model. The results show that when the load of network is constant, the throughputs and buffer contents of nodes are power-law distributed in both space and time. Also the feature of 1/f noise appears in the power spectrum of the change of the number of nodes that bear a fixed part of the system load. It can be seen as yet another example of self-organized criticality. Power-law decay in the distribution of buffer contents implies that heavy network congestion occurs with small probability. The temporal power-law distribution for throughput might be a reasonable explanation for the observed self-similarity in computer network traffic.

  17. Comparing and modelling land use organization in cities

    Science.gov (United States)

    Lenormand, Maxime; Picornell, Miguel; Cantú-Ros, Oliva G.; Louail, Thomas; Herranz, Ricardo; Barthelemy, Marc; Frías-Martínez, Enrique; San Miguel, Maxi; Ramasco, José J.

    2015-01-01

    The advent of geolocated information and communication technologies opens the possibility of exploring how people use space in cities, bringing an important new tool for urban scientists and planners, especially for regions where data are scarce or not available. Here we apply a functional network approach to determine land use patterns from mobile phone records. The versatility of the method allows us to run a systematic comparison between Spanish cities of various sizes. The method detects four major land use types that correspond to different temporal patterns. The proportion of these types, their spatial organization and scaling show a strong similarity between all cities that breaks down at a very local scale, where land use mixing is specific to each urban area. Finally, we introduce a model inspired by Schelling's segregation, able to explain and reproduce these results with simple interaction rules between different land uses. PMID:27019730

  18. Comparing and modeling land use organization in cities

    CERN Document Server

    Lenormand, Maxime; Cantú-Ros, Oliva G; Louail, Thomas; Herranz, Ricardo; Barthelemy, Marc; Frías-Martínez, Enrique; Miguel, Maxi San; Ramasco, José J

    2015-01-01

    The advent of geolocated ICT technologies opens the possibility of exploring how people use space in cities, bringing an important new tool for urban scientists and planners, especially for regions where data is scarce or not available. Here we apply a functional network approach to determine land use patterns from mobile phone records. The versatility of the method allows us to run a systematic comparison between Spanish cities of various sizes. The method detects four major land use types that correspond to different temporal patterns. The proportion of these types, their spatial organization and scaling show a strong similarity between all cities that breaks down at a very local scale, where land use mixing is specific to each urban area. Finally, we introduce a model inspired by Schelling's segregation, able to explain and reproduce these results with simple interaction rules between different land uses.

  19. The contribution of lower vertebrate animal models in human reproduction research.

    Science.gov (United States)

    Chianese, Rosanna; Chioccarelli, Teresa; Cacciola, Giovanna; Ciaramella, Vincenza; Fasano, Silvia; Pierantoni, Riccardo; Meccariello, Rosaria; Cobellis, Gilda

    2011-03-01

    Many advances have been carried out on the estrogens, GnRH and endocannabinoid system that have impact in the reproductive field. Indeed, estrogens, the generally accepted female hormones, have performed an unsuspected role in male sexual functions thanks to studies on non-mammalian vertebrates. Similarly, these animal models have provided important contributions to the identification of several GnRH ligand and receptor variants and their possible involvement in sexual behavior and gonadal function regulation. Moreover, the use of non-mammalian animal models has contributed to a better comprehension about the endocannabinoid system action in several mammalian reproductive events. We wish to highlight here how non-mammalian vertebrate animal model research contributes to advancements with implications on human health as well as providing a phylogenetic perspective on the evolution of reproductive systems in vertebrates.

  20. CONCEPTUAL MODEL OF MARKETING STRATEGIC PLANNING SPECIFIC TO PUBLIC ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Ionescu Florin Tudor

    2012-12-01

    Full Text Available In public services, the political component of the marketing environment has a major importance, as all decisions adopted within central administration influence both the objectives and measures implemented by units of local government and other public service providers. Any discontinuity in the activity of such entities might result in neglecting the real needs of citizens and slowing the reform process in the public sector. Therefore, all initiatives of public organizations must have a unitary goal and integrate harmoniously within a single process. A tool from the management-marketing literature that both contributes to this purpose and leads to an increased customer satisfaction and organizational performance is strategic marketing planning. This paper presents, firstly, requirements and particularities of this process in the public sector, focusing on the need for bottom-up planning, meaning from the functional levels of public service organizations, to the corporate level, where strategic decisions are taken. To achieve this goal, there should be included in the planning process the clients and other audiences, which can provide useful information about the services they want, the quality or the accessibility thereof, and news about the services they need in the future. There are also mentioned the factors that can influence the quality of strategic marketing planning in public services domain: the importance of marketing within the organization, marketing knowledge of employees in marketing departments and/or of management personnel, the efficiency of activities within the organization, and the manager’s marketing vision. In the final part of the paper there are presented the stages of the conceptual model of strategic marketing planning in public services field: (1 accepting the idea of bottom-up planning, (2 avoid or eliminate discrepancies between measures taken at high levels and executions carried out at operational

  1. ORGANIZING SCENARIO VARIABLES BY APPLYING THE INTERPRETATIVE STRUCTURAL MODELING (ISM

    Directory of Open Access Journals (Sweden)

    Daniel Estima de Carvalho

    2009-10-01

    Full Text Available The scenario building method is a thought mode - taken to effect in an optimized, strategic manner - based on trends and uncertain events, concerning a large variety of potential results that may impact the future of an organization.In this study, the objective is to contribute towards a possible improvement in Godet and Schoemaker´s scenario preparation methods, by employing the Interpretative Structural Modeling (ISM as a tool for the analysis of variables.Given this is an exploratory theme, bibliographical research with tool definition and analysis, examples extraction from literature and a comparison exercise of referred methods, were undertaken.It was verified that ISM may substitute or complement the original tools for the analysis of variables of scenarios per Godet and Schoemaker’s methods, given the fact that it enables an in-depth analysis of relations between variables in a shorter period of time, facilitating both structuring and construction of possible scenarios.Key-words: Strategy. Future studies. Interpretative Structural Modeling.

  2. Self-Organization of Aging in a Modified Penna Model

    Science.gov (United States)

    Kim, Gi Ok; Shim, Sugie

    The Penna model for biological aging is modified so that the fertility of each individual is determined by means of the number of activated mutations at that time. A new concept of "good" mutation, which makes an individual to mature enough to reproduce, is introduced. It is assumed that each individual can reproduce only during adulthood, which is determined by the number of activated mutations. The results of Monte Carlo calculations using the modified model show that the ranges of the reproductive age are broadened as time goes by, thus showing self-organization in the biological aging to the direction of the maximum self-conservation. In addition, the population, the survival rate, and the average life span were calculated and analyzed by changing the number of new mutations at birth. It is observed that the higher is the considered number of new mutations at birth, the shorter is the obtained average life span. The mortality functions are also calculated and they showed the exponential increase in adulthood, satisfying the Gompertz law.

  3. Development of an analytical model for organic-fluid fouling

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, C.B.; Watkinson, A.P.

    1994-10-01

    The research goal of this project is to determine ways to effectively mitigate fouling in organic fluids: hydrocarbons and derived fluids. The fouling research focuses on the development of methodology for determining threshold conditions for fouling. Initially, fluid containing chemicals known to produce foulant is analyzed; subsequently, fouling of industrial fluids is investigated. The fouling model developed for determining the effects of physical parameters is the subject of this report. The fouling model is developed on the premise that the chemical reaction for generation of precursor can take place in the bulk fluid, in the thermal-boundary layer, or at the fluid/wall interface, depending upon the interactive effects of fluid dynamics, heat and mass transfer, and the controlling chemical reaction. In the analysis, the experimental data are examined for fouling deposition of polyperoxide produced by autoxidation of indene in kerosene. The effects of fluid and wall temperatures for two flow geometries are analyzed. The results show that the relative effects of physical parameters on the fouling rate differ for the three fouling mechanisms. Therefore, to apply the closed-flow-loop data to industrial conditions, the controlling mechanism must be identified.

  4. A Study of Some Leading Organ Transplant Models in Health Care Systems

    Directory of Open Access Journals (Sweden)

    Yasin Uzuntarla

    2016-04-01

    Full Text Available The most effective treatment method for patients with organ failure is an organ transplant. Although numerous patients are waiting to get organ transplants, the inadequacy in the supply of organs has become a chronic health problem around the whole world. Countries have made various regulations in their health systems that increase the supply of organs and, as a result, various organ transplantation models have been established. Organ transplantation models applied in Spain, the USA, the European Union, Iran, and Turkey have been examined in this study.

  5. KICS: A Model of Motivational Leadership in Organizations

    Directory of Open Access Journals (Sweden)

    John N. N. Ugoani

    2015-09-01

    Full Text Available This pure research gave birth to a Model of Motivational Leadership – KICS: which embraces knowledge, intelligence, collaboration and synergy. It is a synergistic  proposition based on the theory of emotional intelligence as the index of competencies needed for effective leadership. It opened with a general discussion on traditional models of leadership, then the roles of knowledge, intelligence, collaboration and synergy as they relate to motivational leadership. Issues of emotional intelligence clusters and synthesis of the model’s elements were discussed, emphasizing how KICS-based motivational leadership skills can be developed and sustained. Motivational leadership entails exciting people’s imaginations and inspiring them to move in a desired direction. It takes more than simple power to motivate and lead in organizations. Realizing that unity and cohesiveness are built from personal bonds, the best leaders ensure to deepen their rapport with employees and colleagues which enhances organizational performance. This pure research argues that the synergy of related emotional intelligence competencies can lead to motivational leadership behaviour. Knowledge is critical to leadership because there are different types of leadership and different situations require different kinds of knowledge, and the person possessing the knowledge demanded by a certain situation in most cases, tends to become the best leader. A knowledgeable person is one who is trained to consider his actions to undertake them deliberately, in a disciplined manner. Added to this ability is the intelligence to endure in a chosen course in the face of distraction, confusion and difficulty, all combined in producing a motivational leader. Knowledge tends to be procedural in nature and to operate outside of focal awareness. It also reflects the structure of the situation more closely than it does in the structure of formal disciplinary knowledge. The survey research design

  6. Review of existing terrestrial bioaccumulation models and terrestrial bioaccumulation modeling needs for organic chemicals.

    Science.gov (United States)

    Gobas, Frank A P C; Burkhard, Lawrence P; Doucette, William J; Sappington, Keith G; Verbruggen, Eric M J; Hope, Bruce K; Bonnell, Mark A; Arnot, Jon A; Tarazona, Jose V

    2016-01-01

    Protocols for terrestrial bioaccumulation assessments are far less-developed than for aquatic systems. This article reviews modeling approaches that can be used to assess the terrestrial bioaccumulation potential of commercial organic chemicals. Models exist for plant, invertebrate, mammal, and avian species and for entire terrestrial food webs, including some that consider spatial factors. Limitations and gaps in terrestrial bioaccumulation modeling include the lack of QSARs for biotransformation and dietary assimilation efficiencies for terrestrial species; the lack of models and QSARs for important terrestrial species such as insects, amphibians and reptiles; the lack of standardized testing protocols for plants with limited development of plant models; and the limited chemical domain of existing bioaccumulation models and QSARs (e.g., primarily applicable to nonionic organic chemicals). There is an urgent need for high-quality field data sets for validating models and assessing their performance. There is a need to improve coordination among laboratory, field, and modeling efforts on bioaccumulative substances in order to improve the state of the science for challenging substances.

  7. 3D modeling of organic haze in Pluto's atmosphere

    Science.gov (United States)

    Bertrand, Tanguy; Forget, François

    2017-05-01

    The New Horizons spacecraft, which flew by Pluto on July 14, 2015, revealed the presence of haze in Pluto's atmosphere that were formed by CH4/N2 photochemistry at high altitudes in Pluto's atmosphere, as on Titan and Triton. In order to help the analysis of the observations and further investigate the formation of organic haze and its evolution at global scales, we have implemented a simple parameterization of the formation of organic haze in our Pluto General Circulation Model. The production of haze in our model is based on the different steps of aerosol formation as understood on Titan and Triton: photolysis of CH4 in the upper atmosphere by Lyman-α UV radiation, production of various gaseous species, and conversion into solid particles through accumulation and aggregation processes. The simulations use properties of aerosols similar to those observed in the detached haze layer on Titan. We compared two reference simulations ran with a particle radius of 50 nm: with, and without South Pole N2 condensation. We discuss the impact of the particle radius and the lifetime of the precursors on the haze distribution. We simulate CH4 photolysis and the haze formation up to 600 km above the surface. Results show that CH4 photolysis in Pluto's atmosphere in 2015 occurred mostly in the sunlit summer hemisphere with a peak at an altitude of 250 km, though the interplanetary source of Lyman-α flux can induce some photolysis even in the Winter hemisphere. We obtained an extensive haze up to altitudes comparable with the observations, and with non-negligible densities up to 500 km altitude. In both reference simulations, the haze density is not strongly impacted by the meridional circulation. With No South Pole N2 condensation, the maximum nadir opacity and haze extent is obtained at the North Pole. With South Pole N2 condensation, the descending parcel of air above the South Pole leads to a latitudinally more homogeneous haze density with a slight density peak at the South

  8. Towards Increased Relevance: Context-Adapted Models of the Learning Organization

    Science.gov (United States)

    Örtenblad, Anders

    2015-01-01

    Purpose: The purposes of this paper are to take a closer look at the relevance of the idea of the learning organization for organizations in different generalized organizational contexts; to open up for the existence of multiple, context-adapted models of the learning organization; and to suggest a number of such models.…

  9. Towards Increased Relevance: Context-Adapted Models of the Learning Organization

    Science.gov (United States)

    Örtenblad, Anders

    2015-01-01

    Purpose: The purposes of this paper are to take a closer look at the relevance of the idea of the learning organization for organizations in different generalized organizational contexts; to open up for the existence of multiple, context-adapted models of the learning organization; and to suggest a number of such models.…

  10. Evaluation of approaches focused on modelling of organic carbon stocks using the RothC model

    Science.gov (United States)

    Koco, Štefan; Skalský, Rastislav; Makovníková, Jarmila; Tarasovičová, Zuzana; Barančíková, Gabriela

    2014-05-01

    The aim of current efforts in the European area is the protection of soil organic matter, which is included in all relevant documents related to the protection of soil. The use of modelling of organic carbon stocks for anticipated climate change, respectively for land management can significantly help in short and long-term forecasting of the state of soil organic matter. RothC model can be applied in the time period of several years to centuries and has been tested in long-term experiments within a large range of soil types and climatic conditions in Europe. For the initialization of the RothC model, knowledge about the carbon pool sizes is essential. Pool size characterization can be obtained from equilibrium model runs, but this approach is time consuming and tedious, especially for larger scale simulations. Due to this complexity we search for new possibilities how to simplify and accelerate this process. The paper presents a comparison of two approaches for SOC stocks modelling in the same area. The modelling has been carried out on the basis of unique input of land use, management and soil data for each simulation unit separately. We modeled 1617 simulation units of 1x1 km grid on the territory of agroclimatic region Žitný ostrov in the southwest of Slovakia. The first approach represents the creation of groups of simulation units based on the evaluation of results for simulation unit with similar input values. The groups were created after the testing and validation of modelling results for individual simulation units with results of modelling the average values of inputs for the whole group. Tests of equilibrium model for interval in the range 5 t.ha-1 from initial SOC stock showed minimal differences in results comparing with result for average value of whole interval. Management inputs data from plant residues and farmyard manure for modelling of carbon turnover were also the same for more simulation units. Combining these groups (intervals of initial

  11. Development and evaluation of a new sorption model for organic cations in soil: contributions from organic matter and clay minerals.

    Science.gov (United States)

    Droge, Steven T J; Goss, Kai-Uwe

    2013-12-17

    This study evaluates a newly proposed cation-exchange model that defines the sorption of organic cations to soil as a summed contribution of sorption to organic matter (OM) and sorption to phyllosilicate clay minerals. Sorption to OM is normalized to the fraction organic carbon (fOC), and sorption to clay is normalized to the estimated cation-exchange capacity attributed to clay minerals (CECCLAY). Sorption affinity is specified to a fixed medium composition, with correction factors for other electrolyte concentrations. The model applies measured sorption coefficients to one reference OM material and one clay mineral. If measured values are absent, then empirical relationships are available on the basis of molecular volume and amine type in combination with corrective increments for specific polar moieties. The model is tested using new sorption data generated at pH 6 for two Eurosoils, one enriched in clay and the other, OM, using 29 strong bases (pKa > 8). Using experimental data on reference materials for all tested compounds, model predictions for the two soils differed on average by only -0.1 ± 0.4 log units from measured sorption affinities. Within the chemical applicability domain, the model can also be applied successfully to various reported soil sorption data for organic cations. Particularly for clayish soils, the model shows that sorption of organic cations to clay minerals accounts for more than 90% of the overall affinity.

  12. Vienna Soil-Organic-Matter Modeler--Generating condensed-phase models of humic substances.

    Science.gov (United States)

    Sündermann, Axel; Solc, Roland; Tunega, Daniel; Haberhauer, Georg; Gerzabek, Martin H; Oostenbrink, Chris

    2015-11-01

    Humic substances are ubiquitous in the environment and have manifold functions. While their composition is well known, information on the chemical structure and three-dimensional conformation is scarce. Here we describe the Vienna Soil-Organic-Matter Modeler, which is an online tool to generate condensed phase computer models of humic substances (http://somm.boku.ac.at). Many different models can be created that reflect the diversity in composition and conformations of the constituting molecules. To exemplify the modeler, 18 different models are generated based on two experimentally determined compositions, to explicitly study the effect of varying e.g. the amount of water molecules in the models or the pH. Molecular dynamics simulations were performed on the models, which were subsequently analyzed in terms of structure, interactions and dynamics, linking macroscopic observables to the microscopic composition of the systems. We are convinced that this new tool opens the way for a wide range of in silico studies on soil organic matter.

  13. Modeling adsorption and reactions of organic molecules at metal surfaces.

    Science.gov (United States)

    Liu, Wei; Tkatchenko, Alexandre; Scheffler, Matthias

    2014-11-18

    CONSPECTUS: The understanding of adsorption and reactions of (large) organic molecules at metal surfaces plays an increasingly important role in modern surface science and technology. Such hybrid inorganic/organic systems (HIOS) are relevant for many applications in catalysis, light-emitting diodes, single-molecule junctions, molecular sensors and switches, and photovoltaics. Obviously, the predictive modeling and understanding of the structure and stability of such hybrid systems is an essential prerequisite for tuning their electronic properties and functions. At present, density-functional theory (DFT) is the most promising approach to study the structure, stability, and electronic properties of complex systems, because it can be applied to both molecules and solids comprising thousands of atoms. However, state-of-the-art approximations to DFT do not provide a consistent and reliable description for HIOS, which is largely due to two issues: (i) the self-interaction of the electrons with themselves arising from the Hartree term of the total energy that is not fully compensated in approximate exchange-correlation functionals, and (ii) the lack of long-range part of the ubiquitous van der Waals (vdW) interactions. The self-interaction errors sometimes lead to incorrect description of charge transfer and electronic level alignment in HIOS, although for molecules adsorbed on metals these effects will often cancel out in total energy differences. Regarding vdW interactions, several promising vdW-inclusive DFT-based methods have been recently demonstrated to yield remarkable accuracy for intermolecular interactions in the gas phase. However, the majority of these approaches neglect the nonlocal collective electron response in the vdW energy tail, an effect that is particularly strong in condensed phases and at interfaces between different materials. Here we show that the recently developed DFT+vdW(surf) method that accurately accounts for the collective electronic

  14. The prisoner as model organism: malaria research at Stateville Penitentiary

    Science.gov (United States)

    Comfort, Nathaniel

    2009-01-01

    In a military-sponsored research project begun during the Second World War, inmates of the Stateville Penitentiary in Illinois were infected with malaria and treated with experimental drugs that sometimes had vicious side effects. They were made into reservoirs for the disease and they provided a food supply for the mosquito cultures. They acted as secretaries and technicians, recording data on one another, administering malarious mosquito bites and experimental drugs to one another, and helping decide who was admitted to the project and who became eligible for early parole as a result of his participation. Thus, the prisoners were not simply research subjects; they were deeply constitutive of the research project. Because a prisoner’s time on the project was counted as part of his sentence, and because serving on the project could shorten one’s sentence, the project must be seen as simultaneously serving the functions of research and punishment. Michel Foucault wrote about such ‘mixed mechanisms’ in his Discipline and punish. His shining example of such a ‘transparent’ and subtle style of punishment was the panopticon, Jeremy Bentham’s architectural invention of prison cellblocks arrayed around a central guard tower. Stateville prison was designed on Bentham’s model; Foucault featured it in his own discussion. This paper, then, explores the power relations in this highly idiosyncratic experimental system, in which the various roles of model organism, reagent, and technician are all occupied by sentient beings who move among them fluidly. This, I argue, created an environment in the Stateville hospital wing more panoptic than that in the cellblocks. Research and punishment were completely interpenetrating, and mutually reinforcing. PMID:19720327

  15. The prisoner as model organism: malaria research at Stateville Penitentiary.

    Science.gov (United States)

    Comfort, Nathaniel

    2009-09-01

    In a military-sponsored research project begun during the Second World War, inmates of the Stateville Penitentiary in Illinois were infected with malaria and treated with experimental drugs that sometimes had vicious side effects. They were made into reservoirs for the disease and they provided a food supply for the mosquito cultures. They acted as secretaries and technicians, recording data on one another, administering malarious mosquito bites and experimental drugs to one another, and helping decide who was admitted to the project and who became eligible for early parole as a result of his participation. Thus, the prisoners were not simply research subjects; they were deeply constitutive of the research project. Because a prisoner's time on the project was counted as part of his sentence, and because serving on the project could shorten one's sentence, the project must be seen as simultaneously serving the functions of research and punishment. Michel Foucault wrote about such 'mixed mechanisms' in his Discipline and punish. His shining example of such a 'transparent' and subtle style of punishment was the panopticon, Jeremy Bentham's architectural invention of prison cellblocks arrayed around a central guard tower. Stateville prison was designed on Bentham's model; Foucault featured it in his own discussion. This paper, then, explores the power relations in this highly idiosyncratic experimental system, in which the various roles of model organism, reagent, and technician are all occupied by sentient beings who move among them fluidly. This, I argue, created an environment in the Stateville hospital wing more panoptic than that in the cellblocks. Research and punishment were completely interpenetrating, and mutually reinforcing.

  16. Modelling and Optimization of Organization of Workplaces in a Foundry

    Directory of Open Access Journals (Sweden)

    Kukla S.

    2016-09-01

    Full Text Available The paper presents a practical example of improvement of foundry production systems in terms of post-finishing of nodular iron castings produced in the conditions of bulk production for automotive industry. The attention was paid to high labour-intensive efforts, which are difficult to be subjected to mechanization and automation. The times of actions related to grinding processing of castings in three grinding positions connected with a belt conveyor were estimated with the use of a time study method. A bottleneck as well as limiting factors were specified in a system. A number of improvements were proposed, aimed at improving work organization on the castings post-finishing line. An analysis of work ergonomics at the workplace was made in order to eliminate unnecessary and onerous for the employee actions. A model of production system using the Arena software, on which a simulation experiment was conducted, was drawn up in order to visualize the analysed phenomena. The effects of the project were shown on graphs comparing times, costs, work ergonomics and overall efficiency of production equipment indicator.

  17. [Epidemiological intelligence as a model of organization in health].

    Science.gov (United States)

    Rodrigues-Júnior, Antonio Luiz

    2012-03-01

    The concept of epidemiological intelligence, as a construction of information societies, goes beyond monitoring a list of diseases and the ability to elicit rapid responses. The concept should consider the complexity of the definition of epidemiology in the identification of this object of study without being limited to a set of actions in a single government sector. The activities of epidemiological intelligence include risk assessment, strategies for prevention and protection, subsystems of information, crisis management rooms, geographical analysis, etc. This concept contributes to the understanding of policies in health, in multisectorial and geopolitical dimensions, as regards the organization of services around public health emergencies, primary healthcare, as well as disasters. The activities of epidemiological intelligence should not be restricted to scientific research, but the researchers must beware of threats to public health. Lalonde's model enabled consideration of epidemiological intelligence as a way to restructure policies and share resources by creating communities of intelligence, whose purpose is primarily to deal with public health emergencies and disasters.

  18. Modelling Competences for Partner Selection in Service-Oriented Virtual Organization Breeding Environments

    CERN Document Server

    Paszkiewicz, Zbigniew

    2011-01-01

    In the context of globalization and dynamic markets, collaboration among organizations is a condition sine qua non for organizations, especially small and medium enterprises, to remain competitive. Virtual organizations have been proposed as an organizational structure adapted to collaboration among organizations. The concept of Virtual Organization Breeding Environment (VOBE) has been proposed as a means to support the creation and operation of virtual organizations. With the rise of the service-oriented architecture (SOA), the concept of service-oriented VOBE (SOVOBE) has been proposed as a VOBE systematically organized around the concept of services. In the context of SOVOBEs, novel competence models supporting both service orientation and collaboration among organizations have to be developed to support efficiently partner selection, a key aspect of VO creation. In this paper, such a competence model is presented. Our competence model consists of a competence description model, a competence verification m...

  19. Dissecting Ubiquitin Folding Using the Self-Organized Polymer Model.

    Science.gov (United States)

    Reddy, Govardhan; Thirumalai, D

    2015-08-27

    Folding of Ubiquitin (Ub), a functionally important protein found in eukaryotic organisms, is investigated at low and neutral pH at different temperatures using simulations of the coarse-grained self-organized-polymer model with side chains (SOP-SC). The melting temperatures (Tm's), identified with the peaks in the heat capacity curves, decrease as pH decreases, in qualitative agreement with experiments. The calculated radius of gyration, showing dramatic variations with pH, is in excellent agreement with scattering experiments. At Tm, Ub folds in a two-state manner at low and neutral pH. Clustering analysis of the conformations sampled in equilibrium folding trajectories at Tm, with multiple transitions between the folded and unfolded states, shows a network of metastable states connecting the native and unfolded states. At low and neutral pH, Ub folds with high probability through a preferred set of conformations resulting in a pH-dependent dominant folding pathway. Folding kinetics reveal that Ub assembly at low pH occurs by multiple pathways involving a combination of nucleation-collapse and diffusion collision mechanism. The mechanism by which Ub folds is dictated by the stability of the key secondary structural elements responsible for establishing long-range contacts and collapse of Ub. Nucleation collapse mechanism holds if the stability of these elements are marginal, as would be the case at elevated temperatures. If the lifetimes associated with these structured microdomains are on the order of hundreds of microseconds, then Ub folding follows the diffusion-collision mechanism with intermediates, many of which coincide with those found in equilibrium. Folding at neutral pH is a sequential process with a populated intermediate resembling that sampled at equilibrium. The transition state structures, obtained using a Pfold analysis, are homogeneous and globular with most of the secondary and tertiary structures being native-like. Many of our findings for

  20. Models,Characteristics and Upgrade of Rural Tourism Industrial Organizations in Beijing Suburbs

    Institute of Scientific and Technical Information of China (English)

    Hongli; GENG

    2013-01-01

    This paper firstly introduces theoretical basis of researches on industrial organizations of rural tourism.It sums up major models of industrial organizations of rural tourism in Beijing suburbs.Then,it presents benefits and major problems of different models,sums up characteristics of development of rural tourism industrial organizations in Beijing suburbs.Finally,it comes up with recommendations for upgrade and development of rural tourism industrial organizations in Beijing suburbs.

  1. Modelling the subgenual organ of the honeybee, Apis mellifera

    DEFF Research Database (Denmark)

    Storm, Jesper; Kilpinen, Ole

    1998-01-01

    In a recent study on the honeybee (Apis mellifera), the subgenual organ was observed moving inside the leg during sinusoidal vibrations of the leg (Kilpinen and Storm 1997). The subgenual organ of the honeybee is suspended in a haemolymph channel in the tibia of each leg. When the leg accelerates...

  2. Improving Organizations by Replacing the "Mechanical" Model with the "Organic" one

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available Organizations are currently viewed as artificial structures. However, in our opinion, organizations seem to match a biological structure much better. This paper explores this new approach with some interesting conclusions and results: organizations aim at perpetual exis-tence and continuous adaptation. We advance the ideas of organizational "instincts", organizational pathology and organizational optimization using genetic algorithms. In competitive markets, organizations are in a natural selection process, which actually is part of a natural genetic algorithm. This process may be simulated in an artificial multidisciplinary optimization environment, based on minimizing a Total Costs and Risks objective function. Unlike the gradient optimization methods, the genetic algorithms may be applied to such problems with thousands of degrees of freedom. This opens the way to the organizational structure optimization through genetic algorithms.

  3. Participatory plant breeding and organic agriculture: A synergistic model for organic variety development in the United States

    Directory of Open Access Journals (Sweden)

    Adrienne C. Shelton

    2016-12-01

    Full Text Available Abstract Organic farmers require improved varieties that have been adapted to their unique soils, nutrient inputs, management practices, and pest pressures. One way to develop adapted varieties is to situate breeding programs in the environment of intended use, such as directly on organic farms, and in collaboration with organic farmers. This model is a form of participatory plant breeding, and was originally created in order to meet the needs of under-served, small-scale farmers in developing countries. A robust body of literature supports the quantitative genetic selection theory of participatory plant breeding, and helps to explain its increasing prevalence among organic breeding projects in the United States. The history of the organic farming movement in the United States highlights the cultural relevance of engaging organic farmers in the breeding process, complementing the biological rationale for participatory plant breeding. In addition, limited private investment in organic plant breeding encourages the involvement of plant breeders at public institutions. This paper synthesizes the biological, cultural, and economic justifications for utilizing participatory plant breeding as an appropriate methodology for organic cultivar development.

  4. Design of control adaptability system model for TV media organization structure

    Institute of Scientific and Technical Information of China (English)

    WANG Dong-dong; WANG Ya-lin; MA Tao

    2008-01-01

    To resolve the control adaptability problem of TV media in complex competitive environment, a con-trol system model of TV media organization structure was designed. Based on the designed system model for TV media organization structure, the relations among the main factors of the system constitution, missions, organi-zing decision entity, and carrying bodies were analyzed. By means of applying multi-objective decision method and complex control system theory, and combining the integration model of TV media organization structure, the basic model was concluded and the corresponding parameters were designed. The current organization process of TV media is analyzed by this model, which comes to the adaptability appearance with different parameters. The results indicate that the model can estimate current TV media organization structure for the chain appearance of communications and the correlation between platforms and policy-making agencies.

  5. 76 FR 29249 - Medicare Program; Pioneer Accountable Care Organization Model: Request for Applications

    Science.gov (United States)

    2011-05-20

    ... participate in the Pioneer Accountable Care Organization Model for a period beginning in 2011 and ending...://innovations.cms.gov/areas-of-focus/seamless-and-coordinated-care-models/pioneer-aco . Application Submission... Accountable Care Organization Model or the application process. SUPPLEMENTARY INFORMATION: I. Background...

  6. 76 FR 34712 - Medicare Program; Pioneer Accountable Care Organization Model; Extension of the Submission...

    Science.gov (United States)

    2011-06-14

    ...: This notice extends the deadlines for the submission of the Pioneer Accountable Care Organization Model...-coordinated-care-models/pioneer-aco . Application Submission Deadline: Applications must be postmarked on or before August 19, 2011. The Pioneer Accountable Care Organization Model ] Application is available...

  7. Stage-structured matrix models for organisms with non-geometric development times

    Science.gov (United States)

    Andrew Birt; Richard M. Feldman; David M. Cairns; Robert N. Coulson; Maria Tchakerian; Weimin Xi; James M. Guldin

    2009-01-01

    Matrix models have been used to model population growth of organisms for many decades. They are popular because of both their conceptual simplicity and their computational efficiency. For some types of organisms they are relatively accurate in predicting population growth; however, for others the matrix approach does not adequately model...

  8. Current developments in soil organic matter modeling and the expansion of model applications: a review

    Science.gov (United States)

    Campbell, Eleanor E.; Paustian, Keith

    2015-12-01

    Soil organic matter (SOM) is an important natural resource. It is fundamental to soil and ecosystem functions across a wide range of scales, from site-specific soil fertility and water holding capacity to global biogeochemical cycling. It is also a highly complex material that is sensitive to direct and indirect human impacts. In SOM research, simulation models play an important role by providing a mathematical framework to integrate, examine, and test the understanding of SOM dynamics. Simulation models of SOM are also increasingly used in more ‘applied’ settings to evaluate human impacts on ecosystem function, and to manage SOM for greenhouse gas mitigation, improved soil health, and sustainable use as a natural resource. Within this context, there is a need to maintain a robust connection between scientific developments in SOM modeling approaches and SOM model applications. This need forms the basis of this review. In this review we first provide an overview of SOM modeling, focusing on SOM theory, data-model integration, and model development as evidenced by a quantitative review of SOM literature. Second, we present the landscape of SOM model applications, focusing on examples in climate change policy. We conclude by discussing five areas of recent developments in SOM modeling including: (1) microbial roles in SOM stabilization; (2) modeling SOM saturation kinetics; (3) temperature controls on decomposition; (4) SOM dynamics in deep soil layers; and (5) SOM representation in earth system models. Our aim is to comprehensively connect SOM model development to its applications, revealing knowledge gaps in need of focused interdisciplinary attention and exposing pitfalls that, if avoided, can lead to best use of SOM models to support policy initiatives and sustainable land management solutions.

  9. A 360° Vision for Virtual Organizations Characterization and Modelling: Two Intentional Level Aspects

    Science.gov (United States)

    Priego-Roche, Luz-María; Rieu, Dominique; Front, Agnès

    Nowadays, organizations aiming to be successful in an increasingly competitive market tend to group together into virtual organizations. Designing the information system (IS) of such virtual organizations on the basis of the IS of those participating is a real challenge. The IS of a virtual organization plays an important role in the collaboration and cooperation of the participants organizations and in reaching the common goal. This article proposes criteria allowing virtual organizations to be identified and classified at an intentional level, as well as the information necessary for designing the organizations’ IS. Instantiation of criteria for a specific virtual organization and its participants, will allow simple graphical models to be generated in a modelling tool. The models will be used as bases for the IS design at organizational and operational levels. The approach is illustrated by the example of the virtual organization UGRT (a regional stockbreeders union in Tabasco, Mexico).

  10. Modelling organic crystal structures using distributed multipole and polarizability-based model intermolecular potentials.

    Science.gov (United States)

    Price, Sarah L; Leslie, Maurice; Welch, Gareth W A; Habgood, Matthew; Price, Louise S; Karamertzanis, Panagiotis G; Day, Graeme M

    2010-08-14

    Crystal structure prediction for organic molecules requires both the fast assessment of thousands to millions of crystal structures and the greatest possible accuracy in their relative energies. We describe a crystal lattice simulation program, DMACRYS, emphasizing the features that make it suitable for use in crystal structure prediction for pharmaceutical molecules using accurate anisotropic atom-atom model intermolecular potentials based on the theory of intermolecular forces. DMACRYS can optimize the lattice energy of a crystal, calculate the second derivative properties, and reduce the symmetry of the spacegroup to move away from a transition state. The calculated terahertz frequency k = 0 rigid-body lattice modes and elastic tensor can be used to estimate free energies. The program uses a distributed multipole electrostatic model (Q, t = 00,...,44s) for the electrostatic fields, and can use anisotropic atom-atom repulsion models, damped isotropic dispersion up to R(-10), as well as a range of empirically fitted isotropic exp-6 atom-atom models with different definitions of atomic types. A new feature is that an accurate model for the induction energy contribution to the lattice energy has been implemented that uses atomic anisotropic dipole polarizability models (alpha, t = (10,10)...(11c,11s)) to evaluate the changes in the molecular charge density induced by the electrostatic field within the crystal. It is demonstrated, using the four polymorphs of the pharmaceutical carbamazepine C(15)H(12)N(2)O, that whilst reproducing crystal structures is relatively easy, calculating the polymorphic energy differences to the accuracy of a few kJ mol(-1) required for applications is very demanding of assumptions made in the modelling. Thus DMACRYS enables the comparison of both known and hypothetical crystal structures as an aid to the development of pharmaceuticals and other speciality organic materials, and provides a tool to develop the modelling of the

  11. Organic chemistry in the atmosphere. [laboratory modeling of Titan atmosphere

    Science.gov (United States)

    Sagan, C.

    1974-01-01

    The existence of an at least moderately complex organic chemistry on Titan is stipulated based on clear evidence of methane, and at least presumptive evidence of hydrogen in its atmosphere. The ratio of methane to hydrogen is the highest of any atmosphere in the solar system. Irradiation of hydrogen/methane mixtures produces aromatic and aliphatic hydrocarbons. A very reasonable hypothesis assumes that the red cloud cover of Titan is made of organic chemicals. Two-carbon hydrocarbons experimentally produced from irradiated mixtures of methane, ammonia, water, and hydrogen bear out the possible organic chemistry of the Titanian environment.

  12. PROCESS DOCUMENTATION: A MODEL FOR KNOWLEDGE MANAGEMENT IN ORGANIZATIONS.

    Science.gov (United States)

    Haddadpoor, Asefeh; Taheri, Behjat; Nasri, Mehran; Heydari, Kamal; Bahrami, Gholamreza

    2015-10-01

    Continuous and interconnected processes are a chain of activities that turn the inputs of an organization to its outputs and help achieve partial and overall goals of the organization. These activates are carried out by two types of knowledge in the organization called explicit and implicit knowledge. Among these, implicit knowledge is the knowledge that controls a major part of the activities of an organization, controls these activities internally and will not be transferred to the process owners unless they are present during the organization's work. Therefore the goal of this study is identification of implicit knowledge and its integration with explicit knowledge in order to improve human resources management, physical resource management, information resource management, training of new employees and other activities of Isfahan University of Medical Science. The project for documentation of activities in department of health of Isfahan University of Medical Science was carried out in several stages. First the main processes and related sub processes were identified and categorized with the help of planning expert. The categorization was carried out from smaller processes to larger ones. In this stage the experts of each process wrote down all their daily activities and organized them into general categories based on logical and physical relations between different activities. Then each activity was assigned a specific code. The computer software was designed after understanding the different parts of the processes, including main and sup processes, and categorization, which will be explained in the following sections. The findings of this study showed that documentation of activities can help expose implicit knowledge because all of inputs and outputs of a process along with the length, location, tools and different stages of the process, exchanged information, storage location of the information and information flow can be identified using proper

  13. Public attitudes to financial incentive models for organs

    DEFF Research Database (Denmark)

    Hoeyer, Klaus; Schicktanz, Silke; Deleuran, Ida

    2013-01-01

    Waiting lists for organs have stimulated interest in the use of financial incentives for organ donation (FIs), but the literature does not contain an adequate overview of studies of public attitudes toward this mode of procurement. We conducted a literature review of international peer......-reviewed research published between 2002 and 2012 on how members of the public position themselves toward FIs. We identified and analyzed 23 studies using MEDLINE, PsycINFO, Sociological Abstracts and cross-reference search. The search included whole organs, donation, quantitative and empirical qualitative social...... scientific studies on, public attitudes (excluding professionals and medical students). The review reveals a broad divergence of public opinions on financial incentives. However, quantitative studies showed a low overall level of acceptance of payment for organs in living donation (LD); only a slightly...

  14. Modeling the neurodynamic organizations and interactions of teams.

    Science.gov (United States)

    Stevens, Ronald H; Galloway, Trysha L

    2016-01-01

    Across-brain neurodynamic organizations arise when teams perform coordinated tasks. We describe a symbolic electroencephalographic (EEG) approach that identifies when team neurodynamic organizations occur and demonstrate its utility with scientific problem solving and submarine navigation tasks. Each second, neurodynamic symbols (NS) were created showing the 1-40 Hz EEG power spectral densities for each team member. These data streams contained a performance history of the team's across-brain neurodynamic organizations. The degree of neurodynamic organization was calculated each second from a moving window average of the Shannon entropy over the task. Decreased NS entropy (i.e., greater neurodynamic organization) was prominent in the ~16 Hz EEG bins during problem solving, while during submarine navigation, the maximum NS entropy decreases were ~10 Hz and were associated with establishing the ship's location. Decreased NS entropy also occurred in the 20-40 Hz bins of both teams and was associated with uncertainty or stress. The highest mutual information levels, calculated from the EEG values of team dyads, were associated with decreased NS entropy, suggesting a link between these two measures. These studies show entropy and mutual information mapping of symbolic EEG data streams from teams can be useful for identifying organized across-brain team activation patterns.

  15. An evaluation of the applicability of the EPA Organic Leachate Model to leaching of solvent and non-solvent wastes

    OpenAIRE

    Bosserman, Carolyn Whitney

    1989-01-01

    The author evaluated the applicability of the Environmental Protection Agency's Organic Leachate Model to wastes containing organic solvents and other organic compounds ("non-solvents"), and determined that the model tends to overestimate the leaching of organic solvents and other organic compounds. Furthermore, when evaluated for its ability to predict leaching of organic compounds, the model was found to predict the leaching of organic solvent compounds with some accuracy, with a correlatio...

  16. On the Implications of aerosol liquid water and phase separation for modeled organic aerosol mass

    Science.gov (United States)

    Current chemical transport models assume that organic aerosol (OA)-forming compounds partition mostly to a water-poor, organic-rich phase in accordance with their vapor pressures. However, in the southeast United States, a significant fraction of ambient organic compounds are wat...

  17. A depositional model for organic-rich Duvernay Formation mudstones

    Science.gov (United States)

    Knapp, Levi J.; McMillan, Julia M.; Harris, Nicholas B.

    2017-01-01

    The Upper Devonian Duvernay Formation of western Canada is an organic-rich shale formation now targeted as a hydrocarbon reservoir. We present a detailed sedimentological analysis of the Duvernay Formation in order to better understand organic-rich mudstone depositional processes and conditions and to characterize the vertical and lateral heterogeneity of mudstone lithofacies that affect petrophysical and geomechanical rock properties. Organic-rich mudstone facies of the Duvernay Formation were deposited in a dynamic depositional environment by a variety of sediment transport mechanisms, including suspension settling, turbidity currents, and bottom water currents in variably oxygenated bottom waters. Suspension settling dominated in distal relatively deep areas of the basin, but evidence for weak turbidity currents and bottom water currents was observed in the form of graded beds and thin grain-supported siltstone laminae. Organic enrichment primarily occurred in distal areas as a result of bottom water anoxia and low depositional rates of inorganic sediment. In deep water locations near platform margins, alternating silty-sandy contourite beds and organic-rich mudstone beds are present, the former interpreted to have been deposited and reworked by bottom water currents flowing parallel to slope. In shallower, more oxygenated settings, mudstone lithologies vary from calcareous to argillaceous. These sediments were deposited from suspension settling, turbidity currents, and bottom water currents, although primary sedimentary structures are often obscured by extensive bioturbation. Locally, organic enrichment in dysoxic rather than anoxic bottom waters was driven by a slightly increased sedimentation rate and possibly also by aggregation of sedimentary particles in the water column due to interaction between organic matter and clay minerals. Large variations observed in sediment composition, from siliceous to calcareous to argillaceous, reflect multiple biogenic

  18. Application of several activity coefficient models to water-organic-electrolyte aerosols of atmospheric interest

    Directory of Open Access Journals (Sweden)

    T. Raatikainen

    2005-01-01

    Full Text Available In this work, existing and modified activity coefficient models are examined in order to assess their capabilities to describe the properties of aqueous solution droplets relevant in the atmosphere. Five different water-organic-electrolyte activity coefficient models were first selected from the literature. Only one of these models included organics and electrolytes which are common in atmospheric aerosol particles. In the other models, organic species were solvents such as alcohols, and important atmospheric ions like NH4+ could be missing. The predictions of these models were compared to experimental activity and solubility data in aqueous single electrolyte solutions with 31 different electrolytes. Based on the deviations from experimental data and on the capabilities of the models, four predictive models were selected for fitting of new parameters for binary and ternary solutions of common atmospheric electrolytes and organics. New electrolytes (H+, NH4+, Na+, Cl-, NO3- and SO42- and organics (dicarboxylic and some hydroxy acids were added and some modifications were made to the models if it was found useful. All new and most of the existing parameters were fitted to experimental single electrolyte data as well as data for aqueous organics and aqueous organic-electrolyte solutions. Unfortunately, there are very few data available for organic activities in binary solutions and for organic and electrolyte activities in aqueous organic-electrolyte solutions. This reduces model capabilities in predicting solubilities. After the parameters were fitted, deviations from measurement data were calculated for all fitted models, and for different data types. These deviations and the calculated property values were compared with those from other non-electrolyte and organic-electrolyte models found in the literature. Finally, hygroscopic growth factors were calculated for four 100 nm organic-electrolyte particles and these predictions were compared to

  19. Comparison of activity coefficient models for atmospheric aerosols containing mixtures of electrolytes, organics, and water

    Science.gov (United States)

    Tong, Chinghang; Clegg, Simon L.; Seinfeld, John H.

    Atmospheric aerosols generally comprise a mixture of electrolytes, organic compounds, and water. Determining the gas-particle distribution of volatile compounds, including water, requires equilibrium or mass transfer calculations, at the heart of which are models for the activity coefficients of the particle-phase components. We evaluate here the performance of four recent activity coefficient models developed for electrolyte/organic/water mixtures typical of atmospheric aerosols. Two of the models, the CSB model [Clegg, S.L., Seinfeld, J.H., Brimblecombe, P., 2001. Thermodynamic modelling of aqueous aerosols containing electrolytes and dissolved organic compounds. Journal of Aerosol Science 32, 713-738] and the aerosol diameter dependent equilibrium model (ADDEM) [Topping, D.O., McFiggans, G.B., Coe, H., 2005. A curved multi-component aerosol hygroscopicity model framework: part 2—including organic compounds. Atmospheric Chemistry and Physics 5, 1223-1242] treat ion-water and organic-water interactions but do not include ion-organic interactions; these can be referred to as "decoupled" models. The other two models, reparameterized Ming and Russell model 2005 [Raatikainen, T., Laaksonen, A., 2005. Application of several activity coefficient models to water-organic-electrolyte aerosols of atmospheric interest. Atmospheric Chemistry and Physics 5, 2475-2495] and X-UNIFAC.3 [Erdakos, G.B., Change, E.I., Pandow, J.F., Seinfeld, J.H., 2006. Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water—Part 3: Organic compounds, water, and ionic constituents by consideration of short-, mid-, and long-range effects using X-UNIFAC.3. Atmospheric Environment 40, 6437-6452], include ion-organic interactions; these are referred to as "coupled" models. We address the question—Does the inclusion of a treatment of ion-organic interactions substantially improve the performance of the coupled models over

  20. Models of Micro-Organisms: Children's Knowledge and Understanding of Micro-Organisms from 7 to 14 Years Old

    Science.gov (United States)

    Byrne, Jenny

    2011-01-01

    This paper describes the expressed models that children aged 7, 11, and 14 years have about micro-organisms and microbial activity. These were elicited using a variety of data collection techniques that complemented each other, resulting in a rich dataset, and provided information about the level of knowledge and progression of ideas across the…

  1. Health biomarkers in a rat model after intake of organically grown carrots

    DEFF Research Database (Denmark)

    Melballe Jensen, Maja; Jørgensen, Henry; Halekoh, Ulrich

    2012-01-01

    BACKGROUND:Organic foodis perceived as beingofbetter quality andhealthier than conventional foods although the scientific research on organic foodstuffs is highly contradictory. The aim of the present study was to investigate if intake of carrots from four different cultivation systems grown in two...... consecutive years would influence various biomarkers of health in a rat model. All rats were fed a diet with 40% carrot content. The carrots were grown under conventional (C), ‘minimalistic’ organic (O1), organic (O2), or ‘very’ organic cultivation systems (O3). A control group (CO) being fed standard rat...... as a framework for further studies of health in relation to organic foodstuff....

  2. 76 FR 33306 - Medicare Program; Pioneer Accountable Care Organization Model, Request for Applications; Correction

    Science.gov (United States)

    2011-06-08

    ... Care Organization Model: Request for Applications.'' FOR FURTHER INFORMATION CONTACT: Maria Alexander... http://innovations.cms.gov/areas-of-focus/seamless-and-coordinated-care-models/pioneer-aco... HUMAN SERVICES Centers for Medicare & Medicaid Services Medicare Program; Pioneer Accountable...

  3. Importance of global aerosol modeling including secondary organic aerosol formed from monoterpene

    OpenAIRE

    Goto, Daisuke; Takemura, Toshihiko; Nakajima, Teruyuki

    2008-01-01

    A global three-dimensional aerosol transport-radiation model, coupled to an atmospheric general circulation model (AGCM), has been extended to improve the model process for organic aerosols, particularly secondary organic aerosols (SOA), and to estimate SOA contributions to direct and indirect radiative effects. Because the SOA formation process is complicated and unknown, the results in different model simulations include large differences. In this work, we simulate SOA production assuming v...

  4. Fair Trade Organizations and Social Enterprise. Social Innovation through Hybrid Organization Models

    OpenAIRE

    Huybrechts, Benjamin

    2012-01-01

    For several decades, Fair Trade Social Enterprises (FTSEs) have set up partnerships with producer groups in the South and distributed the latter’s products through different types of channels in the North. However, while pioneers in the early years were relatively homogeneous (nonprofit organizations relying on voluntary work and selling through “worldshops”), organizational diversity has tremendously increased in recent times, including other types of legal forms, architectures, and governan...

  5. Keeping the Faith: A Model of Cultural Transmission in Formal Organizations.

    Science.gov (United States)

    Harrison, J. Richard; Carroll, Glenn R.

    1991-01-01

    Develops a cultural transmission model with the following variables: worker entry and exit rate, organization growth rate, recruiting selectivity, socialization intensity, and the rate that socialization decays if not reinforced. A computer simulation of the model found that cultural systems in organizations are highly robust and reach equilibrium…

  6. From Learning Object to Learning Cell: A Resource Organization Model for Ubiquitous Learning

    Science.gov (United States)

    Yu, Shengquan; Yang, Xianmin; Cheng, Gang; Wang, Minjuan

    2015-01-01

    This paper presents a new model for organizing learning resources: Learning Cell. This model is open, evolving, cohesive, social, and context-aware. By introducing a time dimension into the organization of learning resources, Learning Cell supports the dynamic evolution of learning resources while they are being used. In addition, by introducing a…

  7. The Family FIRO Model: A Modest Proposal for Organizing Family Treatment.

    Science.gov (United States)

    Doherty, William J.; Colangelo, Nicholas

    1984-01-01

    Presents a model for organizing family issues and family treatment. Schutz's Fundamental Interpersonal Relations Orientation (FIRO) model is offered as a framework for organizing family issues into inclusion, control, and affection categories, constituting a logical hierarchy of core issues to be dealt with in treating multiproblem families. (JAC)

  8. Plastic as a Carrier of POPs to Aquatic Organisms: A Model Analysis

    NARCIS (Netherlands)

    Koelmans, A.A.; Besseling, E.; Wegner, A.; Foekema, E.M.

    2013-01-01

    It has been hypothesized that persistent organic pollutants (POPs) in microplastic may pose a risk to aquatic organisms. Here we develop and analyze a conceptual model that simulates the effects of plastic on bioaccumulation of POPs. The model accounts for dilution of exposure concentration by sorpt

  9. Modelling the fate of oxidisable organic contaminants in groundwater

    DEFF Research Database (Denmark)

    Barry, D.A.; Prommer, H.; Miller, C.T.

    2002-01-01

    Subsurface contamination by organic chemicals is a pervasive environmental problem, susceptible to remediation by natural or enhanced attenuation approaches or more highly engineered methods such as pump-and-treat, amongst others. Such remediation approaches, along with risk assessment or the pre...

  10. Modeling emissions of volatile organic compounds from silage

    Science.gov (United States)

    Photochemical smog is a major air pollution problem and a significant cause of premature death in the U.S. Smog forms in the presence of volatile organic compounds (VOCs), which are emitted primarily from industry and motor vehicles in the U.S. However, dairy farms may be an important source in so...

  11. Mitochondrial damage and ageing using skin as a model organ.

    Science.gov (United States)

    Hudson, Laura; Bowman, Amy; Rashdan, Eyman; Birch-Machin, Mark A

    2016-11-01

    Ageing describes the progressive functional decline of an organism over time, leading to an increase in susceptibility to age-related diseases and eventually to death, and it is a phenomenon observed across a wide range of organisms. Despite a vast repertoire of ageing studies performed over the past century, the exact causes of ageing remain unknown. For over 50 years it has been speculated that mitochondria play a key role in the ageing process, due mainly to correlative data showing an increase in mitochondrial dysfunction, mitochondrial DNA (mtDNA) damage, and reactive oxygen species (ROS) with age. However, the exact role of the mitochondria in the ageing process remains unknown. The skin is often used to study human ageing, due to its easy accessibility, and the observation that the ageing process is able to be accelerated in this organ via environmental insults, such as ultra violet radiation (UVR). This provides a useful tool to investigate the mechanisms regulating ageing and, in particular, the role of the mitochondria. Observations from dermatological and photoageing studies can provide useful insights into chronological ageing of the skin and other organs such as the brain and liver. Moreover, a wide range of diseases are associated with ageing; therefore, understanding the cause of the ageing process as well as regulatory mechanisms involved could provide potentially advantageous therapeutic targets for the prevention or treatment of such diseases. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Modelling Organic Surfaces with Self-Assembled Monolayers

    Science.gov (United States)

    1989-05-01

    reactive organic liquids. Fluorinated thiols form monolayers that are more water and oil-repellent than Teflon. The hydrophobicity and oleophobicity of...and are both hydrophobic and oleophobic . The surface of a monolayer containing an approximately equal mixture of the two components 13 resembles a

  13. Modeling the Current and Future Roles of Particulate Organic Nitrates in the Southeastern United States.

    Science.gov (United States)

    Pye, Havala O T; Luecken, Deborah J; Xu, Lu; Boyd, Christopher M; Ng, Nga L; Baker, Kirk R; Ayres, Benjamin R; Bash, Jesse O; Baumann, Karsten; Carter, William P L; Edgerton, Eric; Fry, Juliane L; Hutzell, William T; Schwede, Donna B; Shepson, Paul B

    2015-12-15

    Organic nitrates are an important aerosol constituent in locations where biogenic hydrocarbon emissions mix with anthropogenic NOx sources. While regional and global chemical transport models may include a representation of organic aerosol from monoterpene reactions with nitrate radicals (the primary source of particle-phase organic nitrates in the Southeast United States), secondary organic aerosol (SOA) models can underestimate yields. Furthermore, SOA parametrizations do not explicitly take into account organic nitrate compounds produced in the gas phase. In this work, we developed a coupled gas and aerosol system to describe the formation and subsequent aerosol-phase partitioning of organic nitrates from isoprene and monoterpenes with a focus on the Southeast United States. The concentrations of organic aerosol and gas-phase organic nitrates were improved when particulate organic nitrates were assumed to undergo rapid (τ = 3 h) pseudohydrolysis resulting in nitric acid and nonvolatile secondary organic aerosol. In addition, up to 60% of less oxidized-oxygenated organic aerosol (LO-OOA) could be accounted for via organic nitrate mediated chemistry during the Southern Oxidants and Aerosol Study (SOAS). A 25% reduction in nitrogen oxide (NO + NO2) emissions was predicted to cause a 9% reduction in organic aerosol for June 2013 SOAS conditions at Centreville, Alabama.

  14. Modelling the cloud condensation nucleus activity of organic acids

    Directory of Open Access Journals (Sweden)

    Z. Varga

    2007-04-01

    Full Text Available In this study vapour pressure osmometry was used to determine water activity in solutions of organic acids. The surface tension of the solutions was also monitored in parallel and then Köhler curves were calculated for nine organic acids (oxalic, malonic, succinic, glutaric, adipic acid, maleic acid, malic acid, citric acid and pinonic acid. Surface tension depression is negligible for most of the organic acids in dilute (≤1 w/w% solutions. Therefore, these compounds affect the supersaturation only in the beginning phase of droplet formation but not necessarily at the critical size. An exception is cis-pinonic acid which remarkably depress surface tension also in dilute (0.1 w/w% solution and hence at the critical point. The surface tension of organic acid solutions is influenced by the solubility of the compound, the length of the carbon chain and also by the polar functional groups present in the molecule. Similarly to surface tension solubility plays an important role also in water activity: compounds with higher solubility (e.g. malonic, maleic, and glutaric acid reduce water activity significantly in the early phase of droplet formation while less soluble acids (e.g. succinic and adipic acid are saturated in small droplets and the solution starts diluting only in bigger droplets. As a consequence, compounds with lower solubility have a minor effect on water activity in the early phase of droplet formation. To deduce the total effect Köhler curves were calculated and critical supersaturations were determined for the organic acids using measured surface tension and water activity. It was found that critical supersaturation grew with growing carbon number. Oxalic acid had the lowest critical supersaturation in the size range studied and it was comparable to the activation of ammonium sulfate. The Sc values obtained in this study were compared to data from CCNC measurements. In most cases good agreement was found.

  15. Designing an Effective Female Leadership Model in Governmental Organizations

    Directory of Open Access Journals (Sweden)

    Nosratollah MALEKI

    2011-10-01

    Full Text Available Since leadership is a critical factor for improving organizational performance, failure or success of an organization highly depends on the efficiency of leadership at all levels. Scholars elaborated that leadership is the ability of influencing one's attitudes, aptitudes and beliefs, in the way that it will lead to meet organizational objectives. The main purpose of this study is to consider two domains of efficient leadership and women’s leadership style, in order to determine and elaborate the dimensions of the new concept of “Women’s Efficient Leadership”. We intend to describe the characteristics of women’s efficient leadership in state organizations in Iran by means of offering a logical pattern, in order to be able to propose a favorable pattern, leading to increased efficiency in governmental organizations of the country. Innovation of this study can be divided into two parts: one is theoretical contribution and developing the knowledge of efficient leadership as well as women’s leadership style, and the second one is scientific contribution and proposing a pattern for women’s efficient leadership in state organizations, using compound approach. The outcomes of this study show that women’s efficient leadership in state organizations consists of 7 subjects, 17 dimensions, and 85 components, which represent various characteristics in different periods of time. The thesis that women’s efficient leadership has an evolving nature was approved and that it consists of a combination of factors such as capability of team making, having vision, cognitive and psychological capabilities, able to bring continuous improvement of organizational performance, mentoring and making effective relations. In this study, the influence of mentioned factors on women’s efficient leadership has been investigated by means of questionnaires and has been approved.

  16. Speciation of volatile organic compound emissions for regional air quality modeling of particulate matter and ozone

    Science.gov (United States)

    Makar, P. A.; Moran, M. D.; Scholtz, M. T.; Taylor, A.

    2003-01-01

    A new classification scheme for the speciation of organic compound emissions for use in air quality models is described. The scheme uses 81 organic compound classes to preserve both net gas-phase reactivity and particulate matter (PM) formation potential. Chemical structure, vapor pressure, hydroxyl radical (OH) reactivity, freezing point/boiling point, and solubility data were used to create the 81 compound classes. Volatile, semivolatile, and nonvolatile organic compounds are included. The new classification scheme has been used in conjunction with the Canadian Emissions Processing System (CEPS) to process 1990 gas-phase and particle-phase organic compound emissions data for summer and winter conditions for a domain covering much of eastern North America. A simple postprocessing model was used to analyze the speciated organic emissions in terms of both gas-phase reactivity and potential to form organic PM. Previously unresolved compound classes that may have a significant impact on ozone formation include biogenic high-reactivity esters and internal C6-8 alkene-alcohols and anthropogenic ethanol and propanol. Organic radical production associated with anthropogenic organic compound emissions may be 1 or more orders of magnitude more important than biogenic-associated production in northern United States and Canadian cities, and a factor of 3 more important in southern U.S. cities. Previously unresolved organic compound classes such as low vapour pressure PAHs, anthropogenic diacids, dialkyl phthalates, and high carbon number alkanes may have a significant impact on organic particle formation. Primary organic particles (poorly characterized in national emissions databases) dominate total organic particle concentrations, followed by secondary formation and primary gas-particle partitioning. The influence of the assumed initial aerosol water concentration on subsequent thermodynamic calculations suggests that hydrophobic and hydrophilic compounds may form external

  17. Democracy versus Dictatorship in Self-Organized Models of Financial Markets

    CERN Document Server

    D'Hulst, R

    1999-01-01

    Models to mimic the transmission of information in financial markets are introduced. As an attempt to generate the demand process, we distinguish between dictatorship associations, where groups of agents rely on one of them to make decision, and democratic associations, where each agent takes part in the group decision. In the dictatorship model, agents segregate into two distinct populations, while the democratic model is driven towards a critical state where groups of agents of all sizes exist. Hence, both models display a level of organization, but only the democratic model is self-organized. We show that the dictatorship model generates less volatile markets than the democratic model.

  18. Explicit modeling of organic chemistry and secondary organic aerosol partitioning for Mexico City and its outflow plume

    Energy Technology Data Exchange (ETDEWEB)

    Lee-Taylor, J.; Madronich, Sasha; Aumont, B.; Baker, A.; Camredon, M.; Hodzic, Alma; Tyndall, G. S.; Apel, Eric; Zaveri, Rahul A.

    2011-12-21

    The evolution of organic aerosols (OA) in Mexico City and its outflow is investigated with the nearly explicit gas phase photochemistry model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere), wherein precursor hydrocarbons are oxidized to numerous intermediate species for which vapor pressures are computed and used to determine gas/particle partitioning in a chemical box model. Precursor emissions included observed C3-10 alkanes, alkenes, and light aromatics, as well as larger n-alkanes (up to C25) not directly observed but estimated by scaling to particulate emissions according to their volatility. Conditions were selected for comparison with observations made in March 2006 (MILAGRO). The model successfully reproduces the magnitude and diurnal shape for both primary (POA) and secondary (SOA) organic aerosols, with POA peaking in the early morning at 15-20 ug m-3, and SOA peaking at 10-15 μg m-3 during mid-day. The majority (> 75%) of the model SOA stems from the large n-alkanes, with the remainder mostly from the light aromatics. Simulated OA elemental composition reproduces observed H/C and O/C ratios reasonably well, although modeled ratios develop more slowly than observations suggest. SOA chemical composition is initially dominated by *- hydroxy ketones and nitrates from the large alkanes, with contributions from peroxy acyl nitrates and, at later times when NOx is lower, organic hydroperoxides. The simulated plume-integrated OA mass continues to increase for several days downwind despite dilution-induced particle evaporation, since oxidation chemistry leading to SOA formation remains strong. In this model, the plume SOA burden several days downwind exceeds that leaving the city by a factor of >3. These results suggest significant regional radiative impacts of SOA.

  19. Explicit modeling of organic chemistry and secondary organic aerosol partitioning for Mexico City and its outflow plume

    Directory of Open Access Journals (Sweden)

    J. Lee-Taylor

    2011-06-01

    Full Text Available The evolution of organic aerosols (OA in Mexico City and its outflow is investigated with the nearly explicit gas phase photochemistry model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere, wherein precursor hydrocarbons are oxidized to numerous intermediate species for which vapor pressures are computed and used to determine gas/particle partitioning in a chemical box model. Precursor emissions included observed C3–10 alkanes, alkenes, and light aromatics, as well as larger n-alkanes (up to C25 not directly observed but estimated by scaling to particulate emissions according to their volatility. Conditions were selected for comparison with observations made in March 2006 (MILAGRO. The model successfully reproduces the magnitude and diurnal shape for both primary (POA and secondary (SOA organic aerosols, with POA peaking in the early morning at 15–20 μg m−3, and SOA peaking at 10–15 μg m−3 during mid-day. The majority (≥75 % of the model SOA stems from the large n-alkanes, with the remainder mostly from the light aromatics. Simulated OA elemental composition reproduces observed H/C and O/C ratios reasonably well, although modeled ratios develop more slowly than observations suggest. SOA chemical composition is initially dominated by δ-hydroxy ketones and nitrates from the large alkanes, with contributions from peroxy acyl nitrates and, at later times when NOx is lower, organic hydroperoxides. The simulated plume-integrated OA mass continues to increase for several days downwind despite dilution-induced particle evaporation, since oxidation chemistry leading to SOA formation remains strong. In this model, the plume SOA burden several days downwind exceeds that leaving the city by a factor of >3. These results suggest significant regional radiative impacts of SOA.

  20. Self-organized Critical Model Based on Complex Brain Networks with Hierarchical Organization

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying-Yue; ZHANG Gui-Qing; YANG Qiu-Ying; CHEN Tian-Lun

    2008-01-01

    The dynamical behavior in the cortical brain network of macaque is studied by modelling each cortical area with a subnetwork of interacting excitable neurons.We find that the avalanche of our model on different levels exhibits power-law.Furthermore the power-law exponent of the distribution and the average avalanche Size are affected by the topology of the network.

  1. Modelling the fate of organic micropollutants in stormwater ponds

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Eriksson, Eva; Ledin, Anna;

    2011-01-01

    substance inherent properties to calculate MP fate but differ in their ability to represent the small physical scale and high temporal variability of stormwater treatment systems. Therefore the three models generate different results. A Global Sensitivity Analysis (GSA) highlighted that settling....../resuspension of particulate matter was themost sensitive process for the dynamic model. The uncertainty of the estimated MP fluxes can be reduced by calibrating the dynamic model against total suspended solids data. This reduction in uncertainty was more significant for the substances with strong tendency to sorb, i...... models. The fate of four different MP in a stormwater retention pond was simulated by applying two steady-state multimedia fate models (EPI Suite and SimpleBox) commonly applied in chemical risk assessment and a dynamic multimedia fate model (Stormwater Treatment Unit Model for Micro Pollutants — STUMP...

  2. Modeling of multiphase transport of multicomponent organic contaminants and heat in the subsurface: Numerical model formulation

    Science.gov (United States)

    Adenekan, A. E.; Patzek, T. W.; Pruess, K.

    1993-11-01

    A numerical compositional simulator (Multiphase Multicomponent Nonisothermal Organics Transport Simulator (M2NOTS)) has been developed for modeling transient, three-dimensional, nonisothermal, and multiphase transport of multicomponent organic contaminants in the subsurface. The governing equations include (1) advection of all three phases in response to pressure, capillary, and gravity forces; (2) interphase mass transfer that allows every component to partition into each phase present; (3) diffusion; and (4) transport of sensible and latent heat energy. Two other features distinguish M2NOTS from other simulators reported in the groundwater literature: (1) the simulator allows for any number of chemical components and every component is allowed to partition into all fluid phases present, and (2) each phase is allowed to completely disappear from, or appear in, any region of the domain during a simulation. These features are required to model realistic field problems involving transport of mixtures of nonaqueous phase liquid contaminants, and to quantify performance of existing and emerging remediation methods such as vacuum extraction and steam injection.

  3. Neotropical electric fishes (Gymnotiformes as model organisms for bioassays

    Directory of Open Access Journals (Sweden)

    Milena Ferreira

    2015-04-01

    Full Text Available Electric fishes (Gymnotiformes inhabit Central and South America and form a relatively large group with more than 200 species. Besides a taxonomic challenge due to their still unresolved systematic, wide distribution and the variety of habitats they occupy, these fishes have been intensively studied due to their peculiar use of bioelectricity for electrolocation and communication. Conventional analysis of cells, tissues and organs have been complemented with the studies on the electric organ discharges of these fishes. This review compiles the results of 13 bioassays developed during the last 50 years, which used the quickness, low costs and functionality of the bioelectric data collection of Gymnotiformes to evaluate the effects of environmental contaminants and neuroactive drugs.

  4. Neotropical electric fishes (Gymnotiformes) as model organisms for bioassays

    Institute of Scientific and Technical Information of China (English)

    Milena Ferreira; Isac Silva de Jesus; Eliana Feldberg; JoséAntônioAlves-Gomes

    2015-01-01

    Electric fishes (Gymnotiformes) inhabit Central and South America and form a relatively large group with more than 200 species. Besides a taxonomic challenge due to their still unresolved systematic, wide distribution and the variety of habitats they occupy, these fishes have been intensively studied due to their peculiar use of bioelectricity for electrolocation and communication. Conventional analysis of cells, tissues and organs have been complemented with the studies on the electric organ discharges of these fishes. This review compiles the results of 13 bioassays developed during the last 50 years, which used the quickness, low costs and functionality of the bioelectric data collection of Gymnotiformes to evaluate the effects of environmental contaminants and neuroactive drugs.

  5. Organizations

    DEFF Research Database (Denmark)

    Hatch, Mary Jo

    Most of us recognize that organizations are everywhere. You meet them on every street corner in the form of families and shops, study in them, work for them, buy from them, pay taxes to them. But have you given much thought to where they came from, what they are today, and what they might become...... in the future? How and why do they have so much influence over us, and what influences them? How do they contribute to and detract from the meaningfulness of lives, and how might we improve them so they better serve our needs and desires? This Very Short Introductions addresses all of these questions...

  6. [Emission model of volatile organic compounds from materials used indoors].

    Science.gov (United States)

    Han, K

    1998-11-30

    Various materials, such as wall-paper, floor-wax, paint, multicolor wall-coat, air freshener and mothball were experimented in a simulated test chamber under constant selected temperature, humidity and air exchange rate. The relation between the total VOCs concentration and time was regressed by four emission models and the surface emission rate was calculated. The regressed results indicated the similarity among four emission models for the liquid materials with volatile-solvent such as paint and multicolor wall-coat. But for low volatile solid materials, such as wall-paper, floor-wax, mothball, the sink model and the empirical model were better than the dilution model and vapor pressure model. Only for air freshener, it was improper to the total VOCs concentration as a parameter.

  7. Modeling the release of organic contaminants during compost decomposition in soil.

    Science.gov (United States)

    Geng, Chunnu; Haudin, Claire-Sophie; Zhang, Yuan; Lashermes, Gwenaëlle; Houot, Sabine; Garnier, Patricia

    2015-01-01

    Composts, incorporated in soils as amendments, may release organic contaminants during their decomposition. COP-Soil is presented here as a new model to simulate the interaction between organic contaminants and compost, using one module for organic matter and one for organic pollutants, with these modules being linked by several assumptions. Published results of laboratory soil incubations using labeled carbon pollutants from compost were used to test the model for one polycyclic aromatic hydrocarbon (PAH), two surfactants and one herbicide. Several simulation scenarios were tested using (i) the organic pollutant module either alone or coupled to the organic matter module, (ii) various methods to estimate the adsorption coefficients (Kd) of contaminants on organic matter and (iii) different degrading biomasses. The simulations were improved if the organic pollutant module was coupled with the organic matter module. Multiple linear regression model for Kd as a function of organic matter quality yielded the most accurate simulation results. The inclusion of specific biomass in the model made it possible to successfully predict the PAH mineralization.

  8. CONCEPTUAL MODEL OF MARKETING STRATEGIC PLANNING SPECIFIC TO PUBLIC ORGANIZATIONS

    OpenAIRE

    Ionescu Florin Tudor; Barbu Andreea Mihaela

    2012-01-01

    In public services, the political component of the marketing environment has a major importance, as all decisions adopted within central administration influence both the objectives and measures implemented by units of local government and other public service providers. Any discontinuity in the activity of such entities might result in neglecting the real needs of citizens and slowing the reform process in the public sector. Therefore, all initiatives of public organizations must have a unit...

  9. Organisms modeling: The question of radial basis function networks

    Directory of Open Access Journals (Sweden)

    Muzy Alexandre

    2014-01-01

    Full Text Available There exists usually a gap between bio-inspired computational techniques and what biologists can do with these techniques in their current researches. Although biology is the root of system-theory and artifical neural networks, computer scientists are tempted to build their own systems independently of biological issues. This publication is a first-step re-evalution of an usual machine learning technique (radial basis funtion(RBF networks in the context of systems and biological reactive organisms.

  10. Ames Culture Chamber System: Enabling Model Organism Research Aboard the international Space Station

    Science.gov (United States)

    Steele, Marianne

    2014-01-01

    Understanding the genetic, physiological, and behavioral effects of spaceflight on living organisms and elucidating the molecular mechanisms that underlie these effects are high priorities for NASA. Certain organisms, known as model organisms, are widely studied to help researchers better understand how all biological systems function. Small model organisms such as nem-atodes, slime mold, bacteria, green algae, yeast, and moss can be used to study the effects of micro- and reduced gravity at both the cellular and systems level over multiple generations. Many model organisms have sequenced genomes and published data sets on their transcriptomes and proteomes that enable scientific investigations of the molecular mechanisms underlying the adaptations of these organisms to space flight.

  11. Protochordate amphioxus is an emerging model organism for comparative immunology

    Institute of Scientific and Technical Information of China (English)

    Shicui Zhang; Yujun Liang; Guangdong Jia; Zhimeng Zhuang

    2009-01-01

    Protochordate amphioxus is an extant invertebrate regarded quite recently as a basal chordate. It has a vertebrate-like body plan including a circulation system with an organization similar to that of vertebrates. However, amphioxus is less complex than vertebrates for having a genome uncomplicated by extensive genomic duplication, and lacking lymphoid organs and free circulating blood cells.Recent studies on immunity have demonstrated the presence in amphioxus of both the constituent elements of key molecules involved in adaptive immunity such as proto-major histocompatibility complex (proto-MHC), V region-containing chitin-binding protein (VCBP)and V and C domain-bearing protein (VCP), and the complement system operating via the alternative and lectin pathways resembling those seen in vertebrates. In addition, the acute phase response profile in amphioxus has been shown to be similar to that observed in vertebrates. These findings together with the relative structural and genomic simplicity make amphioxus an ideal organism for gaining insights into the origin and evolution of the vertebrate immune system, especially adaptive immunity, and the composition and mech-anisms of the vertebrate innate immunity.

  12. Dynamic root uptake model for neutral lipophilic organics

    DEFF Research Database (Denmark)

    Trapp, Stefan

    2002-01-01

    and output to stem with the transpiration stream plus first-order metabolism and dilution by exponential growth. For chemicals with low or intermediate lipophilicity (log Kow , 2), there was no relevant difference between dynamic model and equilibrium approach. For lipophilic compounds, the dynamic model...... approach. Very lipophilic compounds (e.g., DDT) diffuse very slowly into plant tissue, so they are likely to remain in the peel of root vegetables. In addition, a dynamic (steady-state) flux model for uptake with transpiration water into thick roots is presented. The model considers input from soil...

  13. Modeling the surface tension of complex, reactive organic-inorganic mixtures

    Science.gov (United States)

    Schwier, A. N.; Viglione, G. A.; Li, Z.; McNeill, V. Faye

    2013-11-01

    Atmospheric aerosols can contain thousands of organic compounds which impact aerosol surface tension, affecting aerosol properties such as heterogeneous reactivity, ice nucleation, and cloud droplet formation. We present new experimental data for the surface tension of complex, reactive organic-inorganic aqueous mixtures mimicking tropospheric aerosols. Each solution contained 2-6 organic compounds, including methylglyoxal, glyoxal, formaldehyde, acetaldehyde, oxalic acid, succinic acid, leucine, alanine, glycine, and serine, with and without ammonium sulfate. We test two semi-empirical surface tension models and find that most reactive, complex, aqueous organic mixtures which do not contain salt are well described by a weighted Szyszkowski-Langmuir (S-L) model which was first presented by Henning et al. (2005). Two approaches for modeling the effects of salt were tested: (1) the Tuckermann approach (an extension of the Henning model with an additional explicit salt term), and (2) a new implicit method proposed here which employs experimental surface tension data obtained for each organic species in the presence of salt used with the Henning model. We recommend the use of method (2) for surface tension modeling of aerosol systems because the Henning model (using data obtained from organic-inorganic systems) and Tuckermann approach provide similar modeling results and goodness-of-fit (χ2) values, yet the Henning model is a simpler and more physical approach to modeling the effects of salt, requiring less empirically determined parameters.

  14. Modeling the surface tension of complex, reactive organic-inorganic mixtures

    Directory of Open Access Journals (Sweden)

    A. N. Schwier

    2013-01-01

    Full Text Available Atmospheric aerosols can contain thousands of organic compounds which impact aerosol surface tension, affecting aerosol properties such as cloud condensation nuclei (CCN ability. We present new experimental data for the surface tension of complex, reactive organic-inorganic aqueous mixtures mimicking tropospheric aerosols. Each solution contained 2–6 organic compounds, including methylglyoxal, glyoxal, formaldehyde, acetaldehyde, oxalic acid, succinic acid, leucine, alanine, glycine, and serine, with and without ammonium sulfate. We test two surface tension models and find that most reactive, complex, aqueous organic mixtures which do not contain salt are well-described by a weighted Szyszkowski–Langmuir (S–L model which was first presented by Henning et al. (2005. Two approaches for modeling the effects of salt were tested: (1 the Tuckermann approach (an extension of the Henning model with an additional explicit salt term, and (2 a new implicit method proposed here which employs experimental surface tension data obtained for each organic species in the presence of salt used with the Henning model. We recommend the use of method (2 for surface tension modeling because the Henning model (using data obtained from organic-inorganic systems and Tuckermann approach provide similar modeling fits and goodness of fit (χ2 values, yet the Henning model is a simpler and more physical approach to modeling the effects of salt, requiring less empirically determined parameters.

  15. Molecular Dynamics Modeling of Tethered Organics in Confined Spaces

    Energy Technology Data Exchange (ETDEWEB)

    Waksburg, Avi [Monash University, Australia; Nguyen, M [Monash University, Australia; Chaffe, Alan [Monash University, Australia; Kidder, Michelle [ORNL; Buchanan III, A C [ORNL; Britt, Phillip F [ORNL

    2011-01-01

    A computational method for constructing and evaluating the dynamic behaviour of functionalised hexagonal mesoporous silica (HMS) MCM-41 models is reported. HMS with three pore diameters (1.7, 2.2 and 2.9 nm) were prepared, and, from these, two series of derivative structures were constructed - one with 1,3-diphenylpropyl (DPP) tethers and the other with smaller dimethylsilyl (DMS) tethers attached to the mesopores internal surfaces. Comparison with experimental data shows that simulation results correctly predict the maximum tether density that can be achieved for each tether and each pore diameter. For the smaller pore models, the extent of DPP functionalisation that can be achieved is limited by the available pore volume. However, for the larger pore model, the extent of functionalisation is limited by access to potentially reactive sites on the pore surface. The dynamic behaviour of the models was investigated over a range of temperatures (240-648 K). At lower temperatures (< 400 K), the mobility of DPP tethers in the 2.9 nm model is actually less than that observed in either the 2.2 nm model or the 1.7 nm model due to the extensive non-bonded interactions that are able to develop between tethers and the silica surface at this diameter. At higher temperatures, the free ends of these tethers break away from the surface, extend further into the pore space and the DPP mobility in the 2.9 nm model is higher than in the smaller pore systems.

  16. Modeling cadmium in the feed chain and cattle organs

    NARCIS (Netherlands)

    Fels-Klerx, van der H.J.; Romkens, P.F.A.M.; Franz, E.; Raamsdonk, van L.W.D.

    2011-01-01

    The objectives of this study were to estimate cadmium contamination levels in different scenarios related to soil characteristics and assumptions regarding cadmium accumulation in the animal tissues, using quantitative supply chain modeling. The model takes into account soil cadmium levels, soil pH,

  17. Modeling cadmium in the feed chain and cattle organs

    NARCIS (Netherlands)

    Fels-Klerx, van der H.J.; Romkens, P.F.A.M.; Franz, E.; Raamsdonk, van L.W.D.

    2011-01-01

    The objectives of this study were to estimate cadmium contamination levels in different scenarios related to soil characteristics and assumptions regarding cadmium accumulation in the animal tissues, using quantitative supply chain modeling. The model takes into account soil cadmium levels, soil pH,

  18. Drosophila melanogaster as a Model Organism of Brain Diseases

    Directory of Open Access Journals (Sweden)

    Werner Paulus

    2009-02-01

    Full Text Available Drosophila melanogaster has been utilized to model human brain diseases. In most of these invertebrate transgenic models, some aspects of human disease are reproduced. Although investigation of rodent models has been of significant impact, invertebrate models offer a wide variety of experimental tools that can potentially address some of the outstanding questions underlying neurological disease. This review considers what has been gleaned from invertebrate models of neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, metabolic diseases such as Leigh disease, Niemann-Pick disease and ceroid lipofuscinoses, tumor syndromes such as neurofibromatosis and tuberous sclerosis, epilepsy as well as CNS injury. It is to be expected that genetic tools in Drosophila will reveal new pathways and interactions, which hopefully will result in molecular based therapy approaches.

  19. Incorporating sorption/desorption of organic pollutants into river water quality model

    Institute of Scientific and Technical Information of China (English)

    LOU Bao-feng; ZHU Li-zhong; YANG Kun

    2004-01-01

    Preliminary research was conducted about how to incorporate sorption/desorption of organic pollutants with suspended solids and sediments into single-chemical and one-dimensional water quality model of Jinghang Canal.Sedimentation-resuspension coefficient k3 was deduced; characteristics of organic pollutants, concentrations and components of suspended solids/sediments and hydrological and hydraulic conditions were integrated into k3 and further into river water quality model; impact of sorption/desorption of organic pollutants with suspended solids and sediments on prediction function of the model was discussed. Results demonstrated that this impact is pronounced for organic pollutants with relatively large Koc and Kow, especially when they are also conservative and foc of river suspended solids/sediments is high, and that incorporation of sorption/ desorption of organic pollutants into river water quality model can improve its prediction accuracy.

  20. EXTERNALITIES AND THE SIX FACETS MODEL OF TECHNOLOGY MANAGEMENT: GENETICALLY MODIFIED ORGANISMS IN AGRIBUSINESS

    OpenAIRE

    STEPHEN R. LUXMORE; CLYDE EIRÍKUR HULL

    2010-01-01

    The Six Facets Model of technology management has previously only been applied to process innovation at the firm and the industry level. In this article, the model is applied to product innovation for the first time. In the context of genetically-modified organisms in the agribusiness industry, we examine radical product innovation through the Six Facets Model. We propose, based on the history of genetically-modified organisms in agribusiness, that when applied to product innovation the Six F...

  1. Modeling of iodine radiation chemistry in the presence of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Taghipour, Fariborz; Evans, Greg J. E-mail: evansg@chem-eng.toronto.edu

    2002-06-01

    A kinetic-based model was developed that simulates the radiation chemistry of iodine in the presence of organic compounds. The model's mechanistic description of iodine chemistry and generic semi-mechanistic reactions for various classes of organics, provided a reasonable representation of experimental results. The majority of the model and experimental results of iodine volatilization rates were in agreement within an order of magnitude.

  2. Self-Organizing Maps for Fast LES Combustion Modeling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Tremendous advances have been made in the development of large and accurate detailed reaction chemistry models for hydrocarbon fuels. Comparable progress has also...

  3. Soil Organic Matter Mapping by Decision Tree Modeling

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bin; ZHANG Xing-Gang; WANG Fan; WANG Ren-Chao

    2005-01-01

    Based on a case study of Longyou County, Zhejiang Province, the decision tree, a data mining method, was used to analyze the relationships between soil organic matter (SOM) and other environmental and satellite sensing spatial data.The decision tree associated SOM content with some extensive easily observable landscape attributes, such as landform,geology, land use, and remote sensing images, thus transforming the SOM-related information into a clear, quantitative,landscape factor-associated regular system. This system could be used to predict continuous SOM spatial distribution.By analyzing factors such as elevation, geological unit, soil type, land use, remotely sensed data, upslope contributing area, slope, aspect, planform curvature, and profile curvature, the decision tree could predict distribution of soil organic matter levels. Among these factors, elevation, land use, aspect, soil type, the first principle component of bitemporal Landsat TM, and upslope contributing area were considered the most important variables for predicting SOM. Results of the prediction between SOM content and landscape types sorted by the decision tree showed a close relationship with an accuracy of 81.1%.

  4. Presenting a comprehensive market oriented model and evaluating its impact on organization performance

    Directory of Open Access Journals (Sweden)

    Mohammad Taqi Amini

    2013-08-01

    Full Text Available Like other innovative strategies, companies have paid more attention to market oriented strategies in recent years. This has been focused by organizations for improved effectiveness and the organization performance accelerated a lot in business competition. In responding to this fact, organizations are trying to formulate many of the issues familiar to large organizations, which have involved with market oriented strategy planning. This paper reviews key elements in market-oriented strategy planning with regard to competitiveness and performance in large organizations and outlines a comprehensive model for strategy planning in profit organizations. These elements include environment, top management, organization structure and market oriented strategy. Professional question of this study has a particularly important role in formulating relations of this model. These elements are well positioned to evaluate the impact of market-oriented strategy planning on organizations and their expected impacts on organization performance. A well-organized questionnaire to help organizations with their planning is proposed in this survey. Based on the proposed questionnaire, data obtained from Tehran food industry experts and analyzed by using SEM method. Results accepted eight hypotheses and rejected one.

  5. Retention modeling in combined pH/organic solvent gradient reversed-phase HPLC.

    Science.gov (United States)

    Zisi, Ch; Fasoula, S; Nikitas, P; Pappa-Louisi, A

    2013-07-07

    An approach for retention modeling of double pH/organic solvent gradient data easily generated by automatically mixing two mobile phases with different pH and organic content according to a linear pump program is proposed. This approach is based on retention models arising from the evaluation of the retention data of a set of 17 OPA derivatives of amino acids obtained in 27 combined pH/organic solvent gradient runs performed between fixed initial pH/organic modifier values but different final ones and for different gradient duration. The derived general model is a ninth parameter equation easily manageable through a linear least-squares fitting but it requires eighteen initial pH/organic modifier gradient experiments for a satisfactory retention prediction in various double gradients of the same kind with those used in the fitting procedure. Two simplified versions of the general model, which were parameterized based on six only initial pH/organic modifier gradients, were also proposed, when one of the final double gradient conditions, pH or organic content was kept constant. The full and the simplified models allowed us to predict the experimental retention data in simultaneous pH/organic solvent double gradient mode very satisfactorily without the solution of the fundamental equation of gradient elution.

  6. Modeling the effects of organic nitrogen uptake by plants on the carbon cycling of boreal ecosystems

    Directory of Open Access Journals (Sweden)

    Q. Zhu

    2013-08-01

    Full Text Available Boreal forest and tundra are the major ecosystems in the northern high latitudes in which a large amount of carbon is stored. These ecosystems are nitrogen-limited due to slow mineralization rate of the soil organic nitrogen. Recently, abundant field studies have found that organic nitrogen is another important nitrogen supply for boreal ecosystems. In this study, we incorporated a mechanism that allowed boreal plants to uptake small molecular amino acids into a process-based biogeochemical model, the Terrestrial Ecosystem Model (TEM, to evaluate the impact of organic nitrogen uptake on ecosystem carbon cycling. The new version of the model was evaluated at both boreal forest and tundra sites. We found that the modeled organic nitrogen uptake accounted for 36–87% of total nitrogen uptake by plants in tundra ecosystems and 26–50% for boreal forests, suggesting that tundra ecosystem might have more relied on the organic form of nitrogen than boreal forests. The simulated monthly gross ecosystem production (GPP and net ecosystem production (NEP tended to be larger with the new version of the model since the plant uptake of organic nitrogen alleviated the soil nitrogen limitation especially during the growing season. The sensitivity study indicated that the most important factors controlling the plant uptake of organic nitrogen were the maximum root uptake rate (Imax and the radius of the root (r0 in our model. The model uncertainty due to uncertain parameters associated with organic nitrogen uptake at tundra ecosystem was larger than at boreal forest ecosystems. This study suggests that considering the organic nitrogen uptake by plants is important to boreal ecosystem carbon modeling.

  7. Study of elastic-plastic damage model of cement consolidated soil with high organic content

    Institute of Scientific and Technical Information of China (English)

    CHEN Huie; WANG Qing; CAI Keyi

    2009-01-01

    On the basis of elastic-plastic damage model of cement consolidated soil, the authors took organic contents into reasonable damage variable evolution equation in order to seek relation between the organic contents and parameters in the equation, and established the elastic-plastic damage model of cement consolidated soil considering organic contents. The results show that the parameters change correspondingly with difference of the organic contents. The higher the organic contents are, the less the valves of the parameters such as elastic modulus (E), material parameters (K, n) and damage evolution parameter (ε) become, but the larger strain damage threshold value (εd) of the sample is. Meanwhile, the calculation results obtained from established model are compared with the test data in the condition of common indoors test, which is testified with reliability.

  8. Role of Corporate Culture in Model of Logic Levels of Organization

    Directory of Open Access Journals (Sweden)

    Mariya А. Aleksandrova

    2012-05-01

    Full Text Available The article deals with the level of corporate culture in a model of logic levels of the organization. The modern organization is influenced by the external factors, and therefore it should have the ability to form and accumulate potential for corporate culture in order to ensure a timely response to the external environment and effectively manage the operation and development of numerous elements and subsystems of the organization.

  9. Study on the Organization Model of Wagon Flows in Railway Terminal

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Railway terminal is an important part of railway network. Transport organization of railway terminal is the key of the railway transport organization. Moreover, the organization of transport work is based on the organization of wagon flows in the railway terminal. Because of the great amounts of equipment and a large number of train operations, the study on railway terminal transport organization is mostly focused on a marshalling station in railway terminal or a part of it. Systematic study taking railway terminal as a whole is very few. In this paper, the organization of wagon flows in a railway terminal is analyzed and a wagon flow model in a railway terminal is established. The main principles of organization of local trains are also presented.

  10. Electromagnetic Model Reliably Predicts Radar Scattering Characteristics of Airborne Organisms

    Science.gov (United States)

    Mirkovic, Djordje; Stepanian, Phillip M.; Kelly, Jeffrey F.; Chilson, Phillip B.

    2016-10-01

    The radar scattering characteristics of aerial animals are typically obtained from controlled laboratory measurements of a freshly harvested specimen. These measurements are tedious to perform, difficult to replicate, and typically yield only a small subset of the full azimuthal, elevational, and polarimetric radio scattering data. As an alternative, biological applications of radar often assume that the radar cross sections of flying animals are isotropic, since sophisticated computer models are required to estimate the 3D scattering properties of objects having complex shapes. Using the method of moments implemented in the WIPL-D software package, we show for the first time that such electromagnetic modeling techniques (typically applied to man-made objects) can accurately predict organismal radio scattering characteristics from an anatomical model: here the Brazilian free-tailed bat (Tadarida brasiliensis). The simulated scattering properties of the bat agree with controlled measurements and radar observations made during a field study of bats in flight. This numerical technique can produce the full angular set of quantitative polarimetric scattering characteristics, while eliminating many practical difficulties associated with physical measurements. Such a modeling framework can be applied for bird, bat, and insect species, and will help drive a shift in radar biology from a largely qualitative and phenomenological science toward quantitative estimation of animal densities and taxonomic identification.

  11. Modeling equilibrium adsorption of organic micropollutants onto activated carbon

    KAUST Repository

    De Ridder, David J.

    2010-05-01

    Solute hydrophobicity, polarizability, aromaticity and the presence of H-bond donor/acceptor groups have been identified as important solute properties that affect the adsorption on activated carbon. However, the adsorption mechanisms related to these properties occur in parallel, and their respective dominance depends on the solute properties as well as carbon characteristics. In this paper, a model based on multivariate linear regression is described that was developed to predict equilibrium carbon loading on a specific activated carbon (F400) for solutes reflecting a wide range of solute properties. In order to improve prediction accuracy, groups (bins) of solutes with similar solute properties were defined and solute removals were predicted for each bin separately. With these individual linear models, coefficients of determination (R2) values ranging from 0.61 to 0.84 were obtained. With the mechanistic approach used in developing this predictive model, a strong relation with adsorption mechanisms is established, improving the interpretation and, ultimately, acceptance of the model. © 2010 Elsevier Ltd.

  12. Modeling emissions of volatile organic compounds from silage storages and feed lanes

    Science.gov (United States)

    An initial volatile organic compound (VOC) emission model for silage sources, developed using experimental data from previous studies, was incorporated into the Integrated Farm System Model (IFSM), a whole-farm simulation model used to assess the performance, environmental impacts, and economics of ...

  13. An Introduction to Topic Modeling as an Unsupervised Machine Learning Way to Organize Text Information

    Science.gov (United States)

    Snyder, Robin M.

    2015-01-01

    The field of topic modeling has become increasingly important over the past few years. Topic modeling is an unsupervised machine learning way to organize text (or image or DNA, etc.) information such that related pieces of text can be identified. This paper/session will present/discuss the current state of topic modeling, why it is important, and…

  14. A Modified Earthquake Model of Self-Organized Criticality on Small World Networks

    Institute of Scientific and Technical Information of China (English)

    LIN Min; ZHAO Xiao-Wei; CHEN Tian-Lun

    2004-01-01

    A modified Olami Feder-Christensen model of self-organized criticality on a square lattice with the properties of small world networks has been studied.We find that our model displays power-law behavior and the exponent τ of the model depends on φ,the density of long-range connections in our network.

  15. Teaching Diversified Organic Crop Production Using the Community Supported Agriculture Farming System Model

    Science.gov (United States)

    Falk, Constance L.; Pao, Pauline; Cramer, Christopher S.

    2005-01-01

    An organic garden operated as a community supported agriculture (CSA) venture on the New Mexico State University (NMSU) main campus was begun in January 2002. Students enroll in an organic vegetable production class during spring and fall semesters to help manage and work on the project. The CSA model of farming involves the sale of shares to…

  16. Modelling energy level alignment at organic interfaces and density functional theory

    DEFF Research Database (Denmark)

    Flores, F.; Ortega, J.; Vazquez, Patricia

    2009-01-01

    A review of our theoretical understanding of the band alignment at organic interfaces is presented with particular emphasis on the metal/organic (MO) case. The unified IDIS (induced density of interface states) and the ICT (integer charge transfer) models are reviewed and shown to describe qualit...

  17. The model selection in the process of teambuilding for the management of the organization

    Directory of Open Access Journals (Sweden)

    Sergey Petrov

    2010-10-01

    Full Text Available Improving competitiveness of organizations necessary for their success in a market economy is no longer possible only due to material resources. This implies need for qualitatively new approach to human capital. The author reviews approaches to team building and suggests team management model based on situations-cases in which the organized one way or another team reaches goal.

  18. The control structure of team-based organizations : A diagnostic model for empowerment

    NARCIS (Netherlands)

    Kuipers, Benjamin; de Witte, M.C.

    2005-01-01

    This article describes a diagnostic model for empowerment in team-based organizations that portrays four dimensions of the organization's control structure: the level of routine, the nature of expertise, the level of dependence and the line of command. The combined positions of the set of job

  19. For the Arts To Have Meaning...A Model of Adult Education in Performing Arts Organizations.

    Science.gov (United States)

    Kitinoja, L.; Heimlich, J. E.

    A model of adult education appears to function in the outreach programs of three Columbus (Ohio) performing arts organizations. The first tier represents the arts organization's board of trustees, and the second represents the internal administration of the company. Two administrative bodies are arbitrarily labelled as education and marketing,…

  20. Risk management in organic coffee supply chains : testing the usefulness of critical risk models

    NARCIS (Netherlands)

    Brusselaers, J.F.; Benninga, J.; Hennen, W.H.G.J.

    2011-01-01

    This report documents the findings of the analysis of the supply chain of organic coffee from Uganda to the Netherlands using a Chain Risk Model (CRM). The CRM considers contamination of organic coffee with chemicals as a threat for the supply chain, and analyses the consequences of contamination in

  1. The control structure of team-based organizations : A diagnostic model for empowerment

    NARCIS (Netherlands)

    Kuipers, Benjamin; de Witte, M.C.

    2005-01-01

    This article describes a diagnostic model for empowerment in team-based organizations that portrays four dimensions of the organization's control structure: the level of routine, the nature of expertise, the level of dependence and the line of command. The combined positions of the set of job regula

  2. Teaching Diversified Organic Crop Production Using the Community Supported Agriculture Farming System Model

    Science.gov (United States)

    Falk, Constance L.; Pao, Pauline; Cramer, Christopher S.

    2005-01-01

    An organic garden operated as a community supported agriculture (CSA) venture on the New Mexico State University (NMSU) main campus was begun in January 2002. Students enroll in an organic vegetable production class during spring and fall semesters to help manage and work on the project. The CSA model of farming involves the sale of shares to…

  3. [Structural models of simple sense organs by the example of first metazoans].

    Science.gov (United States)

    Aronova, M Z

    2009-01-01

    Basic variants of the evolutional program for formation of simple sensor system--structural models of gravitation receptor, organ of vision, chemoreceptor organ as well as of the nervous system at early stages of the metazoan phylogenesis--are considered from results of our own morphofunctional studies and literature data.

  4. Modelling soil organic carbon in Danish agricultural soils suggests low potential for future carbon sequestration

    DEFF Research Database (Denmark)

    Taghizadeh-Toosi, Arezoo; Olesen, Jørgen Eivind

    2016-01-01

    Soil organic carbon (SOC) is in active exchange with the atmosphere. The amount of organic carbon (OC) input into the soil and SOC turnover rate are important for predicting the carbon (C) sequestration potential of soils subject to changes in land-use and climate. The C-TOOL model was developed...

  5. Computational Modeling of Cultural Dimensions in Adversary Organizations

    Science.gov (United States)

    2010-01-01

    sons of soil” and contraband- financed civil war types last longer than other types (coups/popular revolutions, anti-colonial wars, and wars in...University of California Press. [122] Cioffi-Revilla, C., and M. I. Midlarsky. 2004. Highest-magnitude warfare: Power laws, scaling, and fractals in the...Terrorism: An Agent-Based Approach.” Chaos, Solitons & Fractals 20. 1 (April 2004): 63-68. [176] Levis, A. H. “Executable Models of Decision

  6. Environmental modelling of use of treated organic waste on agricultural land

    DEFF Research Database (Denmark)

    Hansen, Trine Lund; Christensen, Thomas Højlund; Schmidt, S.

    2006-01-01

    . THE IFEU PROJECT, ORWARE and EASEWASTE are life cycle assessment (LCA) models containing more detailed land application modules. A case study estimating the environmental impacts from land application of 1 ton of composted source sorted organic household waste was performed to compare the results from......Modelling of environmental impacts from the application of treated organic municipal solid waste (MSW) in agriculture differs widely between different models for environmental assessment of waste systems. In this comparative study five models were examined concerning quantification and impact...... assessment of environmental effects from land application of treated organic MSW: DST (Decision Support Tool, USA), IWM (Integrated Waste Management, UK), THE IFEU PROJECT (Germany), ORWARE (ORganic WAste REsearch, Sweden) and EASEWASTE (Environmental Assessment of Solid Waste Systems and Technologies...

  7. Effects of Some Neurobiological Factors in a Self-organized Critical Model Based on Neural Networks

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Ming; ZHANG Ying-Yue; CHEN Tian-Lun

    2005-01-01

    Based on an integrate-and-fire mechanism, we investigate the effect of changing the efficacy of the synapse,the transmitting time-delayed, and the relative refractoryperiod on the self-organized criticality in our neural network model.

  8. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    Science.gov (United States)

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  9. Organic-matter maturation and petroleum generation model in the Yinggehai and Qiongdongnan basins

    Institute of Scientific and Technical Information of China (English)

    郝芳; 李思田; 孙永传; 张启明

    1996-01-01

    The enhancement of organic-matter maturation and petroleum generation by the migration and accumulation of active hydrothermal fluids in the high thermal-gradient, strongly overpressured environments in the Yinggehai and Qiongdongnan basins is systematically demonstrated by combination of geological, geochemical analysis and basin modeling. The retardation of organic-matter thermal evolution by abnormal pore-pressure is recognized, its manifestation and dynamic mechanism are illustrated, and chemical kinetic modeling of the pressure retardation is carried out. On this basis, the model of organic-matter thermal evolution and petroleum generation in high thermal-gradient, strongly overpressured environments is summarized. A correct understanding of the effects of active hydrothermal fluids and abnormal pore-fluid pressures on organic-matter thermal evolution is of great theoretical and practical significance for thermal history analysis, basin modeling and petroleum resource evaluation.

  10. Lessons Learned About Organic Aerosol Formation in the Southeast U.S. Using Observations and Modeling

    Science.gov (United States)

    Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA). In this work, modeling of isoprene SOA via heterogeneous uptake is explored and compared to observations from the Southern Oxidant and Aerosol Study (SOAS).

  11. Tardigrades as a Potential Model Organism in Space Research

    Science.gov (United States)

    Jönsson, K. Ingemar

    2007-10-01

    Exposure of living organisms to open space requires a high level of tolerance to desiccation, cold, and radiation. Among animals, only anhydrobiotic species can fulfill these requirements. The invertebrate phylum Tardigrada includes many anhydrobiotic species, which are adapted to survive in very dry or cold environmental conditions. As a likely by-product of the adaptations for desiccation and freezing, tardigrades also show a very high tolerance to a number of other, unnatural conditions, including exposure to ionizing radiation. This makes tardigrades an interesting candidate for experimental exposure to open space. This paper reviews the tolerances that make tardigrades suitable for astrobiological studies and the reported radiation tolerance in other anhydrobiotic animals. Several studies have shown that tardigrades can survive γ-irradiation well above 1 kilogray, and desiccated and hydrated (active) tardigrades respond similarly to irradiation. Thus, tolerance is not restricted to the dry anhydrobiotic state, and I discuss the possible involvement of an efficient, but yet undocumented, mechanism for DNA repair. Other anhydrobiotic animals (Artemia, Polypedium), when dessicated, show a higher tolerance to γ-irradiation than hydrated animals, possibly due to the presence of high levels of the protective disaccharide trehalose in the dry state. Tardigrades and other anhydrobiotic animals provide a unique opportunity to study the effects of space exposure on metabolically inactive but vital metazoans.

  12. Modeling the World Health Organization Disability Assessment Schedule II using non-parametric item response models.

    Science.gov (United States)

    Galindo-Garre, Francisca; Hidalgo, María Dolores; Guilera, Georgina; Pino, Oscar; Rojo, J Emilio; Gómez-Benito, Juana

    2015-03-01

    The World Health Organization Disability Assessment Schedule II (WHO-DAS II) is a multidimensional instrument developed for measuring disability. It comprises six domains (getting around, self-care, getting along with others, life activities and participation in society). The main purpose of this paper is the evaluation of the psychometric properties for each domain of the WHO-DAS II with parametric and non-parametric Item Response Theory (IRT) models. A secondary objective is to assess whether the WHO-DAS II items within each domain form a hierarchy of invariantly ordered severity indicators of disability. A sample of 352 patients with a schizophrenia spectrum disorder is used in this study. The 36 items WHO-DAS II was administered during the consultation. Partial Credit and Mokken scale models are used to study the psychometric properties of the questionnaire. The psychometric properties of the WHO-DAS II scale are satisfactory for all the domains. However, we identify a few items that do not discriminate satisfactorily between different levels of disability and cannot be invariantly ordered in the scale. In conclusion the WHO-DAS II can be used to assess overall disability in patients with schizophrenia, but some domains are too general to assess functionality in these patients because they contain items that are not applicable to this pathology.

  13. Processes and modeling of hydrolysis of particulate organic matter in aerobic wastewater tratment - A review

    DEFF Research Database (Denmark)

    Morgenroth, Eberhard Friedrich; Kommedal, Roald; Harremoës, Poul

    2002-01-01

    Carbon cycling and the availability of organic carbon for nutrient removal processes are in most wastewater treatment systems restricted by the rate of hydrolysis of slowly biodegradable (particulate) organic matter. To date, the mechanisms of hydrolysis are not well understood for complex...... substrates and mixed populations. Most mathematical models use a simple one-step process to describe hydrolysis. In this article, mechanisms of hydrolysis and mathematical models to describe these processes in wastewater treatment processes are reviewed. Experimental techniques to determine mechanisms...

  14. Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells

    OpenAIRE

    2016-01-01

    A physics-based explicit mathematical model for the external voltage-dependent forward dark current in bulk heterojunction (BHJ) organic solar cells is developed by considering Shockley-Read-Hall (SRH) recombination and solving the continuity equations for both electrons and holes. An analytical model for the external voltage-dependent photocurrent in BHJ organic solar cells is also proposed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (...

  15. Characterization of an organic acid analog model in Adirondack, New York, surface waters

    Science.gov (United States)

    Fakhraei, H.; Driscoll, C. T.

    2013-12-01

    Natural waters include a variety of organic matter that differs in composition and functional groups. Dissolved organic matter is important but difficult to characterize acidic and metal binding (e.g., Al) functional groups in chemical equilibrium models. In this study data from Adirondack Lake Survey were used to calibrate an organic acid analog model in order to quantify the influence of organic acids on surface water chemistry. The study sites in the Adirondack region of New York have diverse levels of dissolved organic carbon (DOC), used as a surrogate for organic acids. DOC in 55 Adirondack surface waters varies from 180 μmol C/l (in Little Echo Pond) to 1263 μmol C/l (in Sunday Pond). To reduce the variability inherited in the large raw data set, suite of mean observations was constructed by grouping and averaging measured data into pH intervals of 0.05 pH units from pH 4.15 to 7.3. A chemical equilibrium model, which includes major solutes in natural waters, was linked to an optimization algorithm (genetic algorithm) to calibrate a triprotic organic analog model which includes proton and aluminum binding by adjusting the dissociation constants and site density of DOC. The object of fitting procedure was to simultaneously minimize the discrepancy between observed and simulated pH, acid neutralizing capacity (ANC), organic monomeric aluminum and inorganic monomeric aluminum. A sensitivity analysis on calibrated values indicate that the speciation of the modeled solutes are most responsive to the dissociation constant of AlOrg= Al3+ + Org3- reaction (Org3- represents organic anion), the site density of DOC and the second H+ dissociation constant of the triprotic organic analog (i.e. H2Org- = 2H+ + Org3- reaction).

  16. [Solute transport modeling application in groundwater organic contaminant source identification].

    Science.gov (United States)

    Wang, Shu-Fang; Wang, Li-Ya; Wang, Xiao-Hong; Lin, Pei; Liu, Jiu-Rong; Xin, Bao-Dong; He, Guo-Ping

    2012-03-01

    Investigation and numerical simulation, based on RT3D (reactive transport in 3-dimensions)were used to identify the source of tetrachloroethylene (PCE) and trichloroethylene (TCE) in the groundwater of a city in the north of China and reverse the input intensity. Multiple regressions were applied to analyze the influenced factors of input intensity of PCE and TCE using Stepwise function in Matlab. The results indicate that the factories and industries are the source of the PCE and TCE in groundwater. Natural attenuation was identified and the natural attenuation rates are 93.15%, 61.70% and 61.00% for PCE, and 70.05%, 73.66% and 63.66% for TCE in 173 days. The 4 source points identified by the simulation have released 0.910 6 kg PCE and 95.693 8 kg TCE during the simulation period. The regression analysis results indicate that local precipitation and the thickness of vadose zone are the main factors influencing organic solution transporting from surface to groundwater. The PCE and TCE concentration are found to be 0 and 5 mg x kg(-1) from surface to 35 cm in vadose zone. All above results suggest that PCE and TCE in groundwater are from the source in the surface. Natural attenuation occurred when PCE and TCE transporting from the surface to groundwater, and the rest was transported to groundwater through vadose zone. Local precipitation was one of the critical factors influencing the transportation of PCE and TCE to aquifer through sand, pebble and gravel of the Quaternary.

  17. A Unifying Organ Model of Pancreatic Insulin Secretion.

    Directory of Open Access Journals (Sweden)

    Andrea De Gaetano

    Full Text Available The secretion of insulin by the pancreas has been the object of much attention over the past several decades. Insulin is known to be secreted by pancreatic β-cells in response to hyperglycemia: its blood concentrations however exhibit both high-frequency (period approx. 10 minutes and low-frequency oscillations (period approx. 1.5 hours. Furthermore, characteristic insulin secretory response to challenge maneuvers have been described, such as frequency entrainment upon sinusoidal glycemic stimulation; substantial insulin peaks following minimal glucose administration; progressively strengthened insulin secretion response after repeated administration of the same amount of glucose; insulin and glucose characteristic curves after Intra-Venous administration of glucose boli in healthy and pre-diabetic subjects as well as in Type 2 Diabetes Mellitus. Previous modeling of β-cell physiology has been mainly directed to the intracellular chain of events giving rise to single-cell or cell-cluster hormone release oscillations, but the large size, long period and complex morphology of the diverse responses to whole-body glucose stimuli has not yet been coherently explained. Starting with the seminal work of Grodsky it was hypothesized that the population of pancreatic β-cells, possibly functionally aggregated in islets of Langerhans, could be viewed as a set of independent, similar, but not identical controllers (firing units with distributed functional parameters. The present work shows how a single model based on a population of independent islet controllers can reproduce very closely a diverse array of actually observed experimental results, with the same set of working parameters. The model's success in reproducing a diverse array of experiments implies that, in order to understand the macroscopic behaviour of the endocrine pancreas in regulating glycemia, there is no need to hypothesize intrapancreatic pacemakers, influences between different

  18. CONVERGENCE TO PROCESS ORGANIZATION BY MODEL OF PROCESS MATURITY

    Directory of Open Access Journals (Sweden)

    Blaženka Piuković Babičković

    2015-06-01

    Full Text Available With modern business process orientation binds primarily, process of thinking and process organizational structure. Although the business processes are increasingly a matter of writing and speaking, it is a major problem among the business world, especially in countries in transition, where it has been found that there is a lack of understanding of the concept of business process management. The aim of this paper is to give a specific contribution to overcoming the identified problem, by pointing out the significance of the concept of business process management, as well as the representation of the model for review of process maturity and tools that are recommended for use in process management.

  19. Self-organized Criticality in a Model Based on Neural Network

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiao-Wei; CHEN Tian-Lun

    2001-01-01

    Based on the LISSOM neural network model, we introduce a model to investigate self-organized criticality in the activity of neural populations. The influence of connection (synapse) between neurons has been adequately considered in this model. It is found to exhibit self-organized criticality (SOC) behavior under appropriate conditions.``We also find that the learning process has promotive influence on emergence of SOC behavior. In addition, we analyze the influence of various factors of the model on the SOC behavior, which is characterized by the power-law behavior of the avalanche size distribution.``

  20. Predicting the lifetime of organic vapor cartridges exposed to volatile organic compound mixtures using a partial differential equations model.

    Science.gov (United States)

    Vuong, François; Chauveau, Romain; Grevillot, Georges; Marsteau, Stéphanie; Silvente, Eric; Vallieres, Cécile

    2016-09-01

    In this study, equilibria, breakthrough curves, and breakthrough times were predicted for three binary mixtures of four volatile organic compounds (VOCs) using a model based on partial differential equations of dynamic adsorption coupling a mass balance, a simple Linear Driving Force (LDF) hypothesis to describe the kinetics, and the well-known Extended-Langmuir (EL) equilibrium model. The model aims to predict with a limited complexity, the BTCs of respirator cartridges exposed to binary vapor mixtures from equilibria and kinetics data obtained from single component. In the model, multicomponent mass transfer was simplified to use only single dynamic adsorption data. The EL expression used in this study predicted equilibria with relatively good accuracy for acetone/ethanol and ethanol/cyclohexane mixtures, but the prediction of cyclohexane uptake when mixed with heptane is less satisfactory. The BTCs given by the model were compared to experimental BTCs to determine the accuracy of the model and the impact of the approximation on mass transfer coefficients. From BTCs, breakthrough times at 10% of the exposure concentration t10% were determined. All t10% were predicted within 20% of the experimental values, and 63% of the breakthrough times were predicted within a 10% error. This study demonstrated that a simple mass balance combined with kinetic approximations is sufficient to predict lifetime for respirator cartridges exposed to VOC mixtures. It also showed that a commonly adopted approach to describe multicomponent adsorption based on volatility of VOC rather than adsorption equilibrium greatly overestimated the breakthrough times.

  1. Scaling of organ subunits in adult mammals and birds: a model.

    Science.gov (United States)

    Prothero, J

    1996-02-01

    Members of one class of organs--including kidney and lung--consist chiefly of repeating units, or subunits, similar in size and shape. Across species, both the number and size of repeating units may increase with increasing organ size. A simple model is proposed, relating the scaling of unit-size and unit-number to that of organ volume. The model makes three structural assumptions, the crucial one, biologically speaking, being that the numerical density of repeating units scales as does organ surface-to-volume ratio. Data were collected from the literature bearing on the number, diameter, total surface area and total volume of such repeating units (i.e., alveoli, air capillaries, renal tubules and glomeruli), for avian and mammalian lung and for mammalian kidney, each as a function of organ size. These data, after log-log transformation, were submitted to standard linear least squares regression analysis. The resultant slopes for nine different regression lines are in good agreement with the model predictions. This finding suggests, surprisingly, that organ scale-up, at least for selected organs, expressed in terms of repeating units, as a function of organ volume, in mammals and birds, and conceivably in other phyla, may be based on a small number of elementary structural principles.

  2. Modeling of the fast organic emissions from a wood-finishing product—Floor wax

    Science.gov (United States)

    Chang, John C. S.; Guo, Zhishi

    Environmental chamber and full-scale residential house tests were conducted to evaluate the fast organic emissions from a wood-finishing product—floor wax. For the environmental chamber tests, a very small amount of (wax was applied to an aluminum plate. It was found that the chamber exit organic concentrations can be estimated by a model with an initial condition of instant organic emissions. The model was applied to the house data to interpret the octane and nonane emissions. Significant sink effects were found in the house that prolonged the elevated octane and nonane concentrations for more than 2 days.

  3. Enhancing Information Systems Security in Educational Organizations in KSA through proposing security model

    Directory of Open Access Journals (Sweden)

    Hussain A.H. Awad

    2011-09-01

    Full Text Available It is well known that technology utilization is not restricted for one sector than the other anymore, Educational organizations share many parts of their information systems with commercial organizations. In this paper we will try to identify the main characteristics of information systems in educational organizations, then we will propose a model of two parts to enhance the information systems security, the first part of the model will handle the policy and laws of the information system, the second part will provide a technical approach on how to audit and subsequently maintain the security of information system.

  4. A model for gyrotactic pattern formation of motile micro-organisms in turbulence

    CERN Document Server

    Gustavsson, K; Jonsson, P R; Mehlig, B

    2015-01-01

    Recent studies show that the dynamics of motile organisms subject to gravitational torques in turbulence gives rise to patchiness. Spherical motile organisms gather in down-welling regions of the turbulent flow. We determine how shape affects preferential sampling and small-scale spatial clustering (determining local encounter rates) by analysing a statistical model in two and three spatial dimensions. By recursively refining approximations for the paths the organisms take through the flow we determine analytically how preferential sampling and small-scale clustering in the model depend upon the dimensionless parameters of the problem. We show that singularities ("caustics") occur in the dynamics and discuss how these singularities affect spatial patterns.

  5. A CONSOLIDATED MODEL OF ANALYSIS OF THE RELATIONS BETWEEN POLITICS AND MANAGEMENT WITHIN PUBLIC ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Catalina Maria GEORGESCU

    2011-01-01

    Full Text Available An interdisciplinary approach which combines the theoretical, empirical andconceptual dimensions, the present study tries to offer a new workperspective on the assessment and modeling of the relation between themanagement of public organizations and the political environment. Thetheoretical research was centered on reviewing the literature on the relationbetween the management of public organizations and the politicalenvironment. The empirical research was materialized by modeling with theregression technique of several aspects integrated to the relations betweenthe management of human resources within public organizations in theeducation field and the external political environment.

  6. Laos Organization Name Using Cascaded Model Based on SVM and CRF

    Directory of Open Access Journals (Sweden)

    Duan Shaopeng

    2017-01-01

    Full Text Available According to the characteristics of Laos organization name, this paper proposes a two layer model based on conditional random field (CRF and support vector machine (SVM for Laos organization name recognition. A layer of model uses CRF to recognition simple organization name, and the result is used to support the decision of the second level. Based on the driving method, the second layer uses SVM and CRF to recognition the complicated organization name. Finally, the results of the two levels are combined, And by a subsequent treatment to correct results of low confidence recognition. The results show that this approach based on SVM and CRF is efficient in recognizing organization name through open test for real linguistics, and the recalling rate achieve 80. 83%and the precision rate achieves 82. 75%.

  7. From cradle to grave: high-throughput studies of aging in model organisms.

    Science.gov (United States)

    Spivey, Eric C; Finkelstein, Ilya J

    2014-07-01

    Aging-the progressive decline of biological functions-is a universal fact of life. Decades of intense research in unicellular and metazoan model organisms have highlighted that aging manifests at all levels of biological organization - from the decline of individual cells, to tissue and organism degeneration. To better understand the aging process, we must first aim to integrate quantitative biological understanding on the systems and cellular levels. A second key challenge is to then understand the many heterogeneous outcomes that may result in aging cells, and to connect cellular aging to organism-wide degeneration. Addressing these challenges requires the development of high-throughput aging and longevity assays. In this review, we highlight the emergence of high-throughput aging approaches in the most commonly used model organisms. We conclude with a discussion of the critical questions that can be addressed with these new methods.

  8. Modeling secondary organic aerosol in an urban area: application to Paris, France

    Directory of Open Access Journals (Sweden)

    F. Couvidat

    2013-01-01

    Full Text Available A secondary organic aerosol (SOA model, H2O (Hydrophilic/Hydrophobic Organic, is evaluated over the Paris area. This model treats the formation of SOA with two kinds of surrogate species: hydrophilic species (which condense preferentially on an aqueous phase and hydrophobic species (which condense only on an organic phase. These surrogates species are formed from the oxidation in the atmosphere of volatile organic compounds (VOC by radicals (HO and NO3 and ozone. These VOC are either biogenic (isoprene, monoterpenes and sesquiterpenes or anthropogenic (mainly aromatic compounds. This model includes the formation of aerosols from different precursors (biogenic precursors, aromatics, and semi-volatile organic compounds (SVOC from traffic. The H2O aerosol model was incorporated into the Polyphemus air quality modeling platform and applied to the Paris area and evaluated by comparison to measurements performed during the Megapoli campaign in July 2009.

    The comparison to measurements in the suburbs and in the city center of Paris shows that the model gives satisfactory results for both elemental carbon (EC and organic carbon (OC. However, the model gives a peak of OC concentrations in the morning due to high emissions from traffic, which does not appear in measurements. Uncertainties in the modeled temperature, which can affect the gas-particle partitioning, in the partitioning of primary SVOC or underestimation of primary organic aerosol (POA evaporation by the model could explain the differences between model and measurements. Moreover, using a theoretical mechanism for the oxidation of primary SVOC and intermediate volatility organic compounds (IVOC, POA concentrations were found to be likely overestimated by models due to the use of simple partitioning constants (which do not take into account the affinity of a compound with the liquid aerosol solution or due to the assumption that the organic aerosol

  9. Modeling secondary organic aerosol in an urban area: application to Paris, France

    Directory of Open Access Journals (Sweden)

    F. Couvidat

    2012-09-01

    Full Text Available A secondary organic aerosol (SOA model, H2O (Hydrophilic/Hydrophobic Organic, is evaluated over the Paris area. This model treats the formation of SOA with two kinds of surrogate species: hydrophilic species (which condense preferentially on an aqueous phase and hydrophobic species (which condense only on an organic phase. These surrogates species are formed from the oxidation in the atmosphere of volatile organic compounds (VOC by radicals (HO and NO3 and ozone. These VOC are either biogenic (isoprene, monoterpenes and sesquiterpenes or anthropogenic (mainly aromatic compounds. This model includes the formation of aerosols from different precursors (biogenic precursors, aromatics, and semi-volatile organic compounds (SVOC from traffic. The H2O aerosol model was incorporated into the Polyphemus air quality modeling platform and applied to the Paris area and evaluated by comparison to measurements performed during the Megapoli campaign in July 2009.

    The comparison to measurements in the suburbs and in the city center of Paris shows that the model gives satisfactory results for both elemental carbon (EC and organic carbon (OC. However, the model gives a peak of OC concentrations in the morning due to high emissions from traffic, which does not appear in measurements. Uncertainties in the modeled temperature, which can affect the gas-particle partitioning, in the partitioning of primary SVOC or underestimation of primary organic aerosol (POA evaporation by the model could explain the differences between model and measurements. Moreover, using a theoretical mechanism for the oxidation of primary SVOC and intermediate volatility organic compounds (IVOC, POA concentrations were found to be likely overestimated by models due to the use of simple partitioning constants (which do not take into account the affinity of a compound with the liquid aerosol solution or due to the assumption that the organic aerosol

  10. [Modeling research about bioremediation of organic pollutants in soil-water-microbes system].

    Science.gov (United States)

    Liu, L; Cui, G; Xia, Z

    2001-03-01

    A new Theory, organic pollutant sequestration inside soil particles, was applied in the research in order to explain the persistence of residual chemicals in remediation sites. Based on this theory, a mathematical model which simulates organic pollutant bioremediation process in soil-water-microbes system was developed. In the model, diffusion is represented by Fick's second law, reversible sorption-desorption by a linear isotherm, irreversible sequestration by a pseudo-first order kinetics, and biodegradation by Monod kinetics. Model results match successfully with experimental data. Model simulations are performed in the study. It is noteworthy that the mathematical model will be useful in quantitatively predicting the time and degradation extend of organic pollutant in remediation sites.

  11. A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

    Science.gov (United States)

    Zuend, A.; Marcolli, C.; Luo, B. P.; Peter, T.

    2008-08-01

    Tropospheric aerosols contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behaviour. By means of activity coefficients, non-ideal behaviour can be taken into account. We present here a thermodynamic model named AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) that is able to calculate activity coefficients covering inorganic, organic, and organic-inorganic interactions in aqueous solutions over a wide concentration range. This model is based on the activity coefficient model LIFAC by Yan et al. (1999) that we modified and reparametrised to better describe atmospherically relevant conditions and mixture compositions. Focusing on atmospheric applications we considered H+, Li+, Na+, K+, NH+4, Mg2+, Ca2+, Cl-, Br-, NO-3, HSO-4, and SO2-4 as cations and anions and a wide range of alcohols/polyols composed of the functional groups CHn and OH as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are well represented up to high ionic strength. Most notably, a semi-empirical middle-range parametrisation of direct organic-inorganic interactions in alcohol+water+salt solutions strongly improves the agreement between experimental and modelled activity coefficients. At room temperature, this novel thermodynamic model offers the possibility to compute equilibrium relative humidities, gas/particle partitioning and liquid-liquid phase separations with high accuracy. In further studies, other organic functional groups will be introduced. The model framework is not restricted to specific ions or organic compounds and is therefore also applicable for other research topics.

  12. A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2008-08-01

    Full Text Available Tropospheric aerosols contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behaviour. By means of activity coefficients, non-ideal behaviour can be taken into account. We present here a thermodynamic model named AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients that is able to calculate activity coefficients covering inorganic, organic, and organic-inorganic interactions in aqueous solutions over a wide concentration range. This model is based on the activity coefficient model LIFAC by Yan et al. (1999 that we modified and reparametrised to better describe atmospherically relevant conditions and mixture compositions. Focusing on atmospheric applications we considered H+, Li+, Na+, K+, NH+4, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO2−4 as cations and anions and a wide range of alcohols/polyols composed of the functional groups CHn and OH as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are well represented up to high ionic strength. Most notably, a semi-empirical middle-range parametrisation of direct organic-inorganic interactions in alcohol+water+salt solutions strongly improves the agreement between experimental and modelled activity coefficients. At room temperature, this novel thermodynamic model offers the possibility to compute equilibrium relative humidities, gas/particle partitioning and liquid-liquid phase separations with high accuracy. In further studies, other organic functional groups will be introduced. The model framework is not restricted to specific ions or organic compounds and is therefore also

  13. Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions

    Science.gov (United States)

    Jathar, Shantanu H.; Woody, Matthew; Pye, Havala O. T.; Baker, Kirk R.; Robinson, Allen L.

    2017-03-01

    Gasoline- and diesel-fueled engines are ubiquitous sources of air pollution in urban environments. They emit both primary particulate matter and precursor gases that react to form secondary particulate matter in the atmosphere. In this work, we updated the organic aerosol module and organic emissions inventory of a three-dimensional chemical transport model, the Community Multiscale Air Quality Model (CMAQ), using recent, experimentally derived inputs and parameterizations for mobile sources. The updated model included a revised volatile organic compound (VOC) speciation for mobile sources and secondary organic aerosol (SOA) formation from unspeciated intermediate volatility organic compounds (IVOCs). The updated model was used to simulate air quality in southern California during May and June 2010, when the California Research at the Nexus of Air Quality and Climate Change (CalNex) study was conducted. Compared to the Traditional version of CMAQ, which is commonly used for regulatory applications, the updated model did not significantly alter the predicted organic aerosol (OA) mass concentrations but did substantially improve predictions of OA sources and composition (e.g., POA-SOA split), as well as ambient IVOC concentrations. The updated model, despite substantial differences in emissions and chemistry, performed similar to a recently released research version of CMAQ (Woody et al., 2016) that did not include the updated VOC and IVOC emissions and SOA data. Mobile sources were predicted to contribute 30-40 % of the OA in southern California (half of which was SOA), making mobile sources the single largest source contributor to OA in southern California. The remainder of the OA was attributed to non-mobile anthropogenic sources (e.g., cooking, biomass burning) with biogenic sources contributing to less than 5 % to the total OA. Gasoline sources were predicted to contribute about 13 times more OA than diesel sources; this difference was driven by differences in

  14. Evaluating a model of anaerobic digestion of organic wastes through system identification

    Energy Technology Data Exchange (ETDEWEB)

    Anex, R.P.; Kiely, G.

    1999-07-01

    Anaerobic digestion of the organic fraction of municipal solid waste (MSW), on its own or co-digested with primary sewage sludge (PSS), produces high quality biogas, suitable as renewable energy. Parameter estimation and evaluation of a two-stage mathematical model of the anaerobic co-digestion of the organic fraction of MSW and PSS are described. Measured data are from a bench scale laboratory experiment using a continuously stirred tank reactor and operated at 36 C for 115 days. The two-stage model simulates acidogenesis and methanogenesis, including ammonia inhibition. Model parameters are estimated using an output error, Levenberg-Marquardt (LM) algorithm. Sensitivity of the estimated parameter values and the model outputs to non-estimated model parameters and measurement errors are evaluated. The estimated mathematical model successfully predicts the performance of the anaerobic reactor. Sensitivity results provide guidance for improving the model structure and experimental procedures.

  15. Kinetic modelling of nitrogen and organics removal in vertical and horizontal flow wetlands.

    Science.gov (United States)

    Saeed, Tanveer; Sun, Guangzhi

    2011-05-01

    This paper provides a comparative evaluation of the kinetic models that were developed to describe the biodegradation of nitrogen and organics removal in wetland systems. Reaction kinetics that were considered in the model development included first order kinetics, Monod and multiple Monod kinetics; these kinetics were combined with continuous-stirred tank reactor (CSTR) or plug flow pattern to produce equations to link inlet and outlet concentrations of each key pollutants across a single wetland. Using three statistical parameters, a critical evaluation of five potential models was made for vertical and horizontal flow wetlands. The results recommended the models that were developed based on Monod models, for predicting the removal of nitrogen and organics in a vertical and horizontal flow wetland system. No clear correlation was observed between influent BOD/COD values and kinetic coefficients of BOD(5) in VF and HF wetlands, illustrating that the removal of biodegradable organics was insensitive to the nature of organic matter. Higher effluent COD/TN values coincided with greater denitrification kinetic coefficients, signifying the dependency of denitrification on the availability of COD in VF wetland systems. In contrast, the trend was opposite in HF wetlands, indicating that availability of NO(3)-N was the main limiting step for nitrogen removal. Overall, the results suggested the possible application of the developed alternative predictive models, for understanding the complex biodegradation routes of nitrogen and organics removal in VF and HF wetland systems.

  16. Parametrization of organic nitrogen mineralization models in soil treated with swine raising wastewater

    Directory of Open Access Journals (Sweden)

    Demétrius David da Silva

    2010-08-01

    Full Text Available Little is known about the mineralization dynamic of organic nitrogen contained in swine manure, so models need to be adjusted for its prediction. The objective of the present study was to parameterize and assess models of organic nitrogen mineralization in soil treated with swine raising wastewater (SRW at different temperatures and water contents. Samples of 57.3 cm3 of dystrophic Red-Yellow Latosol were mixed with SRW at the application dose of 400 kg ha-1 nitrogen, placed in plastic cups and incubated at four different temperatures (15, 20, 25 and 35°C and water contents corresponding to tensions of 10, 30, 200 and 1500 kPa. Samples were removed from the incubated soil after 3, 6, 12, 24, 48 and 96 days to quantify the ammonium and nitrate concentrations. The parameters of the soil organic nitrogen mineralization models were determined from the organic nitrogen mineralization values obtained over the different incubation periods. The value of the potentially mineralizable nitrogen (N0 in soil with application of SRW was superior that of the soil without application of SRW. The mineralization constant (k in soil with application of SRW was always superior that of the soil without application of SRW. There was a tendency for the simple exponential model to underestimate the values of the mineralized nitrogen concentration. In most of the situations the potential model was more efficient than the simple exponential model to predict the mineralization of the organic nitrogen.

  17. Homeotic Genes and the ABCDE Model for Floral Organ Formation in Wheat

    Directory of Open Access Journals (Sweden)

    Koji Murai

    2013-06-01

    Full Text Available Floral organ formation has been the subject of intensive study for over 20 years, particularly in the model dicot species Arabidopsis thaliana. These studies have led to the establishment of a general model for the development of floral organs in higher plants, the so-called ABCDE model, in which floral whorl-specific combinations of class A, B, C, D, or E genes specify floral organ identity. In Arabidopsis, class A, B, C, D, E genes encode MADS-box transcription factors except for the class A gene APETALA2. Mutation of these genes induces floral organ homeosis. In this review, I focus on the roles of these homeotic genes in bread wheat (Triticum aestivum, particularly with respect to the ABCDE model. Pistillody, the homeotic transformation of stamens into pistil-like structures, occurs in cytoplasmic substitution (alloplasmic wheat lines that have the cytoplasm of the related wild species Aegilops crassa. This phenomenon is a valuable tool for analysis of the wheat ABCDE model. Using an alloplasmic line, the wheat ortholog of DROOPING LEAF (TaDL, a member of the YABBY gene family, has been shown to regulate pistil specification. Here, I describe the current understanding of the ABCDE model for floral organ formation in wheat.

  18. MATRIX-VBS Condensing Organic Aerosols in an Aerosol Microphysics Model

    Science.gov (United States)

    Gao, Chloe Y.; Tsigaridis, Konstas; Bauer, Susanne E.

    2015-01-01

    The condensation of organic aerosols is represented in a newly developed box-model scheme, where its effect on the growth and composition of particles are examined. We implemented the volatility-basis set (VBS) framework into the aerosol mixing state resolving microphysical scheme Multiconfiguration Aerosol TRacker of mIXing state (MATRIX). This new scheme is unique and advances the representation of organic aerosols in models in that, contrary to the traditional treatment of organic aerosols as non-volatile in most climate models and in the original version of MATRIX, this new scheme treats them as semi-volatile. Such treatment is important because low-volatility organics contribute significantly to the growth of particles. The new scheme includes several classes of semi-volatile organic compounds from the VBS framework that can partition among aerosol populations in MATRIX, thus representing the growth of particles via condensation of low volatility organic vapors. Results from test cases representing Mexico City and a Finish forrest condistions show good representation of the time evolutions of concentration for VBS species in the gas phase and in the condensed particulate phase. Emitted semi-volatile primary organic aerosols evaporate almost completely in the high volatile range, and they condense more efficiently in the low volatility range.

  19. Analisis Tingkat Motivasi Siswa Dalam Pembelajaran IPA Model Advance Organizer Berbasis Proyek

    Directory of Open Access Journals (Sweden)

    Tasiwan -

    2014-04-01

    Full Text Available atur kemajuan (advance organizer berbasis proyek. Sampel penelitian dipilih secara acak. Pada kelas  eksperimen diterapkan model pembelajaran advance organizer berbasis proyek sedangkan pada kelas kontrol diterapkan pembelajaran langsung (direct instruction tanpa advance organizer. Sebelum pembelajaran di kelas, siswa eksperimen dikelompokkan menjadi 8 kelompok yang terdiri atas 4 – 5 siswa. Setiap kelompok ditugaskan untuk merealisasikan proyek bel listrik, rangkaian arus seri – paralel, dan tuas. Produk proyek digunakan dalam pembelajaran dikelas sebagai advance organizer. Data diperoleh melalui observasi partisipatif, penilaian produk, peta konsep, laporan eksperimen, dan angket. Instrumen motivasi menggunakan skala motivasi ARCS. Hasil penelitian menunjukkan bahwa kelas eksperimen memiliki tingkat motivasi lebih baik dalam aspek perhatian, relevansi, kepercayaan diri, dan kepuasan pembelajaran dengan rata – rata tingkat motivasi sebesar 77,20, sedangkan tanpa advance organizer berbasis proyek sebesar 71,10. Disarankan siswa diberikan kemandirian penuh dalam proyek. This study was conducted to analyze the level of student motivation in learning science through models of advance organizer  based project . Samples were selected at random . In the experimental class advance organizer applied learning model based on a class project while learning control direct instruction without advance organizer . Prior learning in the classroom , students are grouped into 8 experimental groups consisting of 4-5 students . Each group was assigned a project to realize an electric bell , the circuit current series - parallel , and lever . Products used in a learning class project as advance organizer . The data obtained through participant observation , assessment product , concept maps , experimental reports , and questionnaires . Motivation instrument using ARCS motivation scale . Results showed that the experimental class had better motivation level

  20. Improved AIOMFAC model parameterisation of the temperature dependence of activity coefficients for aqueous organic mixtures

    Directory of Open Access Journals (Sweden)

    G. Ganbavale

    2014-06-01

    Full Text Available This study presents a new, improved parameterisation of the temperature dependence of activity coefficients in the AIOMFAC (Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients model applicable for aqueous as well as water-free organic solutions. For electrolyte-free organic and organic–water mixtures the AIOMFAC model uses a group-contribution approach based on UNIFAC (UNIversal quasi-chemical Functional-group Activity Coefficients. This group-contribution approach explicitly accounts for interactions among organic functional groups and between organic functional groups and water. The previous AIOMFAC version uses a simple parameterisation of the temperature dependence of activity coefficients, aimed to be applicable in the temperature range from ~275 to ~400 K. With the goal to improve the description of a wide variety of organic compounds found in atmospheric aerosols, we extend the AIOMFAC parameterisation for the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon to atmospherically relevant low temperatures with the introduction of a new temperature dependence parameterisation. The improved temperature dependence parameterisation is derived from classical thermodynamic theory by describing effects from changes in molar enthalpy and heat capacity of a multicomponent system. Thermodynamic equilibrium data of aqueous organic and water-free organic mixtures from the literature are carefully assessed and complemented with new measurements to establish a comprehensive database, covering a wide temperature range (~190 to ~440 K for many of the functional group combinations considered. Different experimental data types and their processing for the estimation of AIOMFAC model parameters are discussed. The new AIOMFAC parameterisation for the temperature dependence of activity coefficients from low to high temperatures shows an overall improvement of

  1. Sorption of organic compounds to activated carbons. Evaluation of isotherm models

    NARCIS (Netherlands)

    Pikaar, I.; Koelmans, A.A.; Noort, van P.C.M.

    2006-01-01

    Sorption to 'hard carbon' (black carbon, coal, kerogen) in soils and sediments is of major importance for risk assessment of organic pollutants. We argue that activated carbon (AC) may be considered a model sorbent for hard carbon. Here, we evaluate six sorption models on a literature dataset for so

  2. Strategy and the Learning Organization: A Maturity Model for the Formation of Strategy

    Science.gov (United States)

    Kenny, John

    2006-01-01

    Purpose: To develop a theoretical model for strategic change that links learning in an organization to the strategic process. Design/methodology/approach: The model was developed from a review of literature covering a range of areas including: management, strategic planning, psychology of learning and organizational learning. The process of…

  3. Advancing the flatworm Macrostomum lignano as a versatile model organism for stem cell research

    NARCIS (Netherlands)

    Demircan, T.D.

    2013-01-01

    Flatworms are a classical model for regeneration and stem cell research due to their astonishing regeneration capacity facilitated by pluripotent stem cells called neoblasts. M. lignano has several important experimental properties that make it a convenient model organism: the transparency of the an

  4. Using NLP meta, Milton, metaphor models, for improving the activity of the organization

    Directory of Open Access Journals (Sweden)

    Cornel Marian IOSIF

    2010-12-01

    Full Text Available The objective of this paper is the improving of the three methods from the neuro- linguistic programming – metaphor, Milton model and the meta-model, so by using this in daily activities by an organization to improve the activities witch, are performed and to have a more efficient allocation of the available resources.

  5. Using a knowledge elicitation method to specify the business model of a human factors organization

    NARCIS (Netherlands)

    Schraagen, J.M.C.; Ven, J. van de; Hoffman, R.R.; Moon, B.M.

    2009-01-01

    Concept Mapping was used to structure knowledge elicitation interviews with a group of human factors specialists whose goal was to describe the business model of their Department. This novel use of cognitive task analysis to describe the business model of a human factors organization resulted in a n

  6. A Performance Enhanced Interactive Learning Workshop Model as a Supplement for Organic Chemistry Instruction

    Science.gov (United States)

    Phillips, Karen E. S.; Grose-Fifer, Jilliam

    2011-01-01

    In this study, the authors describe a Performance Enhanced Interactive Learning (PEIL) workshop model as a supplement for organic chemistry instruction. This workshop model differs from many others in that it includes public presentations by students and other whole-class-discussion components that have not been thoroughly investigated in the…

  7. A Performance Enhanced Interactive Learning Workshop Model as a Supplement for Organic Chemistry Instruction

    Science.gov (United States)

    Phillips, Karen E. S.; Grose-Fifer, Jilliam

    2011-01-01

    In this study, the authors describe a Performance Enhanced Interactive Learning (PEIL) workshop model as a supplement for organic chemistry instruction. This workshop model differs from many others in that it includes public presentations by students and other whole-class-discussion components that have not been thoroughly investigated in the…

  8. Using a knowledge elicitation method to specify the business model of a human factors organization

    NARCIS (Netherlands)

    Schraagen, J.M.C.; Ven, J. van de; Hoffman, R.R.; Moon, B.M.

    2009-01-01

    Concept Mapping was used to structure knowledge elicitation interviews with a group of human factors specialists whose goal was to describe the business model of their Department. This novel use of cognitive task analysis to describe the business model of a human factors organization resulted in a n

  9. Using a knowledge elicitation method to specify the business model of a human factors organization.

    NARCIS (Netherlands)

    Schraagen, Johannes Martinus Cornelis; van de Ven, Josine; Hoffman, Robert R.; Moon, Brian M.

    2009-01-01

    Concept Mapping was used to structure knowledge elicitation interviews with a group of human factors specialists whose goal was to describe the business model of their Department. This novel use of cognitive task analysis to describe the business model of a human factors organization resulted in a n

  10. Activating Global Operating Models: The bridge from organization design to performance

    Directory of Open Access Journals (Sweden)

    Amy Kates

    2015-07-01

    Full Text Available This article introduces the concept of activation and discusses its use in the implementation of global operating models by large multinational companies. We argue that five particular activators help set in motion the complex strategies and organizations required by global operating models.

  11. Modelling uptake into roots and subsequent translocation of neutral and ionisable organic compounds

    DEFF Research Database (Denmark)

    Trapp, Stefan

    2000-01-01

    A study on uptake of neutral and dissociating organic compounds from soil solution into roots, and their subsequent translocation, was undertaken using model simulations. The model approach combines the processes of lipophilic sorption, electrochemical interactions, ion trap, advection in xylem a...

  12. A review of animal models used to evaluate potential allergenicity of genetically modified organisms (GMOs)

    DEFF Research Database (Denmark)

    Marsteller, Nathan; Bøgh, Katrine Lindholm; Goodman, Richard E.

    2017-01-01

    Food safety regulators request prediction of allergenicity for newly expressed proteins in genetically modified (GM) crops and in novel foods. Some have suggested using animal models to assess potential allergenicity. A variety of animal models have been used in research to evaluate sensitisation...... of genetically modified organisms (GMOs)....

  13. Computational modeling of luminous bacteria self-organization on the cylindrical container side surface

    Directory of Open Access Journals (Sweden)

    Žilvinas Ledas

    2013-09-01

    Full Text Available This paper deals with the computational modeling of the pattern formation of luminous bacteria. Two bacterial self-organization models are investigated – Keller-Segel diffusion-advection-reaction type equations and the model with additional oxygen equation. These models were applied for the modeling of fluid cultures of lux-gene engineered Escherichia coli in the cylindrical container as seen from the side in 2 dimensions and in quasi-1 dimension along the top three phase contact line. The spatiotemporal patterns were simulated by using the finite difference technique. By applying these models the influence of the cylindrical container depth on the pattern formation was investigated.

  14. A simple model for the distribution and fate of organic chemicals in a landfill: MOCLA

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Christensen, Thomas Højlund

    2001-01-01

    of degradation and transformation in the landfill. Local equilibrium is assumed for the distribution of the chemicals in the landfill as expressed by Henry’s Law for the leachate-gas interface, and by the linear partition coefficient based on the waste solid organic carbon content for the waste......A simple mathematical model (MOCLA: Model for Organic Chemicals in Landfills) is presented, describing the distribution of organic chemicals between leachate, gas and solid waste. The model also predicts the fate of the chemicals in terms of emissions with leachate and landfill gas and in terms......-leachate interface. Degradation of the chemicals is expressed as a first order reaction. Annual specific leachate and gas generation data in combination with data on landfill area and volume allow for prediction of main emission routes. Model simulations involving two landfill scenarios for a number of chemicals...

  15. Synthetic Optimization Model and Algorithm for Railway Freight Center Station Location and Wagon Flow Organization Problem

    Directory of Open Access Journals (Sweden)

    Xing-cai Liu

    2014-01-01

    Full Text Available The railway freight center stations location and wagon flow organization in railway transport are interconnected, and each of them is complicated in a large-scale rail network. In this paper, a two-stage method is proposed to optimize railway freight center stations location and wagon flow organization together. The location model is present with the objective to minimize the operation cost and fixed construction cost. Then, the second model of wagon flow organization is proposed to decide the optimal train service between different freight center stations. The location of the stations is the output of the first model. A heuristic algorithm that combined tabu search (TS with adaptive clonal selection algorithm (ACSA is proposed to solve those two models. The numerical results show the proposed solution method is effective.

  16. Position-specific isotope modeling of organic micropollutants transformation through different reaction pathways

    DEFF Research Database (Denmark)

    Jin, Biao; Rolle, Massimo

    2016-01-01

    The degradation of organic micropollutants occurs via different reaction pathways. Compound specific isotope analysis is a valuable tool to identify such degradation pathways in different environmental systems. We propose a mechanism-based modeling approach that provides a quantitative framework...... to simultaneously evaluate concentration as well as bulk and position-specific multi-element isotope evolution during the transformation of organic micropollutants. The model explicitly simulates position-specific isotopologues for those atoms that experience isotope effects and, thereby, provides a mechanistic...... description of isotope fractionation occurring at different molecular positions. To demonstrate specific features of the modeling approach, we simulated the degradation of three selected organic micropollutants: dichlorobenzamide (BAM), isoproturon (IPU) and diclofenac (DCF). The model accurately reproduces...

  17. Model of sustainable utilization of organic solids waste in Cundinamarca, Colombia

    Directory of Open Access Journals (Sweden)

    Solanyi Castañeda Torres

    2017-05-01

    Full Text Available Introduction: This article considers a proposal of a model of use of organic solids waste for the department of Cundinamarca, which responds to the need for a tool to support decision-making for the planning and management of organic solids waste. Objective: To perform an approximation of a conceptual technical and mathematician optimization model to support decision-making in order to minimize environmental impacts. Materials and methods: A descriptive study was applied due to the fact that some fundamental characteristics of the studied homogeneous phenomenon are presented and it is also considered to be quasi experimental. The calculation of the model for plants of the department is based on three axes (environmental, economic and social, that are present in the general equation of optimization. Results: A model of harnessing organic solids waste in the techniques of biological treatment of composting aerobic and worm cultivation is obtained, optimizing the system with the emissions savings of greenhouse gases spread into the atmosphere, and in the reduction of the overall cost of final disposal of organic solids waste in sanitary landfill. Based on the economic principle of utility that determines the environmental feasibility and sustainability in the plants of harnessing organic solids waste to the department, organic fertilizers such as compost and humus capture carbon and nitrogen that reduce the tons of CO2.

  18. Integrated model for predicting the fate of organics in waste-water treatment plants

    Energy Technology Data Exchange (ETDEWEB)

    Govind, R.; Lai, L.; Dobbs, R.

    1991-01-01

    An integrated Fate Model has been developed for predicting the fate of organics in a wastewater treatment plant. The Fate Model has been validated using experimental data from a pilot-scale facility. The biodegradation kinetic constants for some compounds in the Fate Model were estimated using the group contribution approach. The Fate Model has been compared with other existing models in the literature. Potential applications of the Fate Model include assessment of volatile organic compound (VOC) emissions from a wastewater treatment plant, evaluate pretreatment requirements prior to discharge to the sewer system, predict concentrations of toxic compounds on sludges, and provide a general framework for estimating the removal of toxic compounds during activated sludge treatment.

  19. VOML: A Framework for Modelling Virtual Organizations and Virtual Breeding Environment

    Directory of Open Access Journals (Sweden)

    Noor Jahan Rajper

    2015-07-01

    Full Text Available This paper presents the VOML (Virtual Organization Modelling Language framework. VOML is a formal approach for specifying VOs (Virtual Organizations and their VBEs (Virtual Breeding Environments.The VOML framework allows domain users to model a system in terms of their domain terminology and from that domain specific model IT community can derive a complete operational model closer to underlying execution environment. The framework is a collection of three sub-languages, each covering different aspects which are considered paramount at a particular level of VO representation. We present VOML and its underlying methodological approach in detail and demonstrate how to model VOs. Our focus will be on the methodological approach that VOML supports and on the language primitives that VOML offers for modelling VOs.

  20. Prediction of the thermal decomposition of organic peroxides by validated QSPR models

    Energy Technology Data Exchange (ETDEWEB)

    Prana, Vinca [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Rotureau, Patricia, E-mail: patricia.rotureau@ineris.fr [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Fayet, Guillaume [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); André, David; Hub, Serge [ARKEMA, rue Henri Moissan, BP63, Pierre Benite 69493 (France); Vicot, Patricia [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Rao, Li [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Adamo, Carlo [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Institut Universitaire de France, 103 Boulevard Saint Michel, Paris F-75005 (France)

    2014-07-15

    Highlights: • QSPR models were developed for thermal stability of organic peroxides. • Two accurate MLR models were exhibited based on quantum chemical descriptors. • Performances were evaluated by a series of internal and external validations. • The new QSPR models satisfied all OCDE principles of validation for regulatory use. - Abstract: Organic peroxides are unstable chemicals which can easily decompose and may lead to explosion. Such a process can be characterized by physico-chemical parameters such as heat and temperature of decomposition, whose determination is crucial to manage related hazards. These thermal stability properties are also required within many regulatory frameworks related to chemicals in order to assess their hazardous properties. In this work, new quantitative structure–property relationships (QSPR) models were developed to predict accurately the thermal stability of organic peroxides from their molecular structure respecting the OECD guidelines for regulatory acceptability of QSPRs. Based on the acquisition of 38 reference experimental data using DSC (differential scanning calorimetry) apparatus in homogenous experimental conditions, multi-linear models were derived for the prediction of the decomposition heat and the onset temperature using different types of molecular descriptors. Models were tested by internal and external validation tests and their applicability domains were defined and analyzed. Being rigorously validated, they presented the best performances in terms of fitting, robustness and predictive power and the descriptors used in these models were linked to the peroxide bond whose breaking represents the main decomposition mechanism of organic peroxides.

  1. Description of adsorption of hydrophobic organic compounds on sediment using multi-component adsorption model

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A chemical sequential separation procedure for sediment bas been developed for the adsorptive investigation of hydrophobic organic compounds(HOCs) including four fractions: carbonate, hydrous metallic oxide(ferric oxide, manganese oxide and alumina), clay and organic matter. Adsorption isotherms of these hydrophobic solute probes, such as hexachloroethane, lindane and 1,2,4,5-tetrachlorobenzene were measured for model sorbents, model and natural sediment, and the latter of which was pretreated with the simplified sequential separation method. The linear and Langmuir models are applied to correlate the experimental data of humic substance and other model sorbents respectively. Multi-component Adsorptive Model (MCAM) was used to simulate adsorption isotherms of model and natural sediment. The results reveal that( 1 ) the separation efficiencies of carbonate, organic matter, ferric oxide, manganese oxide and alumina are 98. 1 % , 72.5% ,82.6%, 93.5% and 83.3%, respectively; (2) except for removing metallic oxide, the external structure of sediment is not changed greatly after separation; (3) the MCAM correlates the data of adsorption isotherm rather well with the maximal relative deviations of 9.76 % , 6.78 %and 9.53% for hexachloroethane, lindane and 1,2,4,5-tetrachlorobenaze in model sediment, respectively. The MCAM can clearly give expression to the different adsorptive mechanisms for HOCs in organic and inorganic matter, though the experimental data in each component are not very accurate due to the sequential separation efficiency.

  2. Development and assessment of quantitative structureactivity relationship models for bioconcentration factors of organic pollutants

    Institute of Scientific and Technical Information of China (English)

    QIN Hong; CHEN JingWen; WANG Ying; WANG Bin; LI XueHua; LI Fei; WANG YaNan

    2009-01-01

    Bioconcentration factors (BCFs) are of great importance for ecological risk assessment of organic chemicals. In this study, a quantitative structure-activity relationship (QSAR) model for fish BCFs of 8 groups of compounds was developed employing partial least squares (PLS) regression, based on lin-ear solvation energy relationship (LSER) theory and theoretical molecular structural descriptors. The guidelines for development and validation of QSAR models proposed by the Organization for Economic Co-operation and Development (OECD) were followed. The model results show that the main factors governing IogBCF are Connolly molecular area (CMA), average molecular polarizability (α) and mo-lecular weight (Mw). Thus molecular size plays a critical role in affecting the bioconcentration of organic pollutants in fish. For the established model, the multiple correlation coefficient square (R2Y)2=0.868, the root mean square error (RMSE)=0.553 log units, and the leave-many-out cross-validated Q2CUM=0.860, indicating its good goodness-of-fit and robustness. The model predictivity was evaluated by external validation, with the external explained variance (Q2EXT)=0.755 and RMSE=0.647 log units. Moreover, the applicability domain of the developed model was assessed and visualized by the Williams plot. The developed QSAR model can be used to predict fish logBCF for organic chemicals within the application domain.

  3. Construction and Evaluation of the Theoretical Model of Citrus Cooperative Organization

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the general overview of cooperative economic organizations of citrus industry at home and abroad,theoretical model of the modernization,industrialization and marketization of Citrus Cooperative Organization is established.After selecting the indices,such as the scale of production,the scale of management,the rate of encouraged farmers,and the market competitiveness,quantitative evaluation index system for modernization,industrialization and marketization is established.Then,Citrus Cooperative Organization is divided into three stages,such as primary stage,intermediate stage and senior stage.After evaluating the modernization,industrialization and marketization of citrus industry in the United States,Spain and South Africa,it is pointed out that the Citrus Cooperative Organization in China at present is at the primary stage.Finally,policy direction of the development of Citrus Cooperative Organization in China is pointed out.

  4. Prediction of soil sorption coefficients using model molecular structures for organic matter and the quantum mechanical COSMO-SAC model.

    Science.gov (United States)

    Phillips, Kathy L; Di Toro, Dominic M; Sandler, Stanley I

    2011-02-01

    The soil sorption coefficient, K(OC), is an important property affecting the environmental fate of organic molecules. Difficulties associated with measuring K(OC) have led to many attempts to predict this property, but most rely on empirical descriptors for the soil phase determined from correlations with measured K(OC) data, and are thereby limited by the data quality and diversity. A new method is presented to predict K(OC) for nonionic organic compounds that requires only molecular structures. No calibration is performed. Using model humic acid (HA) and fulvic acid (FA) molecular structures from the literature, the soil organic matter is modeled as an organic solvent composed of HA or FA molecules. K(OC) is predicted as an organic solvent-water partition coefficient using the quantum mechanics-based model COSMO-SAC. The log K(OC) values for a set of 440 diverse, environmentally relevant chemicals are predicted with a root-mean-square error of 0.84-1.08, depending on which model HA or FA is used.

  5. Inhomogeneous and Self-Organized Temperature in Schelling-Ising Model

    Science.gov (United States)

    Müller, Katharina; Schulze, Christian; Stauffer, Dietrich

    The Schelling model of 1971 is a complicated version of a square-lattice Ising model at zero temperature, to explain urban segregation, based on the neighbor preferences of the residents, without external reasons. Various versions between Ising and Schelling models give about the same results. Inhomogeneous "temperatures" T do not change the results much, while a feedback between segregation and T leads to a self-organization of an average T.

  6. Modeling and simulating command and control for organizations under extreme situations

    CERN Document Server

    Moon, Il-Chul; Kim, Tag Gon

    2013-01-01

    Commanding and controlling organizations in extreme situations is a challenging task in military, intelligence, and disaster management. Such command and control must be quick, effective, and considerate when dealing with the changing, complex, and risky conditions of the situation. To enable optimal command and control under extremes, robust structures and efficient operations are required of organizations. This work discusses how to design and conduct virtual experiments on resilient organizational structures and operational practices using modeling and simulation. The work illustrates key a

  7. MATRIX-VBS: implementing an evolving organic aerosol volatility in an aerosol microphysics model

    OpenAIRE

    Gao, Chloe Y.; Tsigaridis, Kostas; Bauer, Susanne E.

    2016-01-01

    We have implemented an existing aerosol microphysics scheme into a box model framework and extended it to represent gas-particle partitioning and chemical ageing of semi-volatile organic aerosols. We then applied this new research tool to investigate the effects of semi-volatile organic species on the growth, composition and mixing state of aerosol particles in case studies representing several different environments. The volatility-basis set (VBS) framework is implemented into the aerosol mi...

  8. Do organic surface films on sea salt aerosols influence atmospheric chemistry? ─ a model study

    Directory of Open Access Journals (Sweden)

    R. von Glasow

    2007-11-01

    Full Text Available Organic material from the ocean's surface can be incorporated into sea salt aerosol particles often producing a surface film on the aerosol. Such an organic coating can reduce the mass transfer between the gas phase and the aerosol phase influencing sea salt chemistry in the marine atmosphere. To investigate these effects and their importance for the marine boundary layer (MBL we used the one-dimensional numerical model MISTRA. We considered the uncertainties regarding the magnitude of uptake reduction, the concentrations of organic compounds in sea salt aerosols and the oxidation rate of the organics to analyse the possible influence of organic surfactants on gas and liquid phase chemistry with a special focus on halogen chemistry. By assuming destruction rates for the organic coating based on laboratory measurements we get a rapid destruction of the organic monolayer within the first meters of the MBL. Larger organic initial concentrations lead to a longer lifetime of the coating but lead also to an unrealistically strong decrease of O3 concentrations as the organic film is destroyed by reaction with O3. The lifetime of the film is increased by assuming smaller reactive uptake coefficients for O3 or by assuming that a part of the organic surfactants react with OH. With regard to tropospheric chemistry we found that gas phase concentrations for chlorine and bromine species decreased due to the decreased mass transfer between gas phase and aerosol phase. Aqueous phase chlorine concentrations also decreased but aqueous phase bromine concentrations increased. Differences for gas phase concentrations are in general smaller than for liquid phase concentrations. The effect on gas phase NO2 or NO is very small (reduction less than 5% whereas liquid phase NO2 concentrations increased in some cases by nearly 100%. We list suggestions for further laboratory studies which are needed for improved model studies.

  9. Maximizing Return on Investment (ROI of Enterprise Resource Planning Systems (ERP for Nonprofit Organizations: Proposed Model

    Directory of Open Access Journals (Sweden)

    Hussain A.H. Awad

    2013-08-01

    Full Text Available ERP are the core business application for many companies; and it’s very apparent that organization spending on those systems is in a continuous rise, on the other hand this also raised the issue of how can ERP systems pay those spending; and when that investment can reach ROI point. In this study the researcher will attempt to propose a model that contains guide line phases for nonprofit organizations in order to speed up the stage in which ERP system can reach ROI, the researcher opted for universities since they are one of the main nonprofit organizations that employ ERP in their processes.

  10. Challenges in modelling dissolved organic matter dynamics in agricultural soil using DAISY

    DEFF Research Database (Denmark)

    Gjettermann, Birgitte; Styczen, Merete; Hansen, Hans Christian Bruun

    2008-01-01

    Because dissolved organic matter (DOM) plays an important role is terrestrial C-, N- and P-balances and transport of these three components to aquatic environments, there is a need to include it in models. This paper presents the concept of the newly developed DOM modules implemented in the DAISY...... pedotransfer functions taking into account the soil content of organic matter, Al and Fe oxides. The turnover of several organic matter pools including one DOM pool are described by first-order kinetics. The DOM module was tested at field scale for three soil treatments applied after cultivating grass...

  11. N-gram analysis of 970 microbial organisms reveals presence of biological language models

    Directory of Open Access Journals (Sweden)

    Ganapathiraju Madhavi K

    2011-01-01

    Full Text Available Abstract Background It has been suggested previously that genome and proteome sequences show characteristics typical of natural-language texts such as "signature-style" word usage indicative of authors or topics, and that the algorithms originally developed for natural language processing may therefore be applied to genome sequences to draw biologically relevant conclusions. Following this approach of 'biological language modeling', statistical n-gram analysis has been applied for comparative analysis of whole proteome sequences of 44 organisms. It has been shown that a few particular amino acid n-grams are found in abundance in one organism but occurring very rarely in other organisms, thereby serving as genome signatures. At that time proteomes of only 44 organisms were available, thereby limiting the generalization of this hypothesis. Today nearly 1,000 genome sequences and corresponding translated sequences are available, making it feasible to test the existence of biological language models over the evolutionary tree. Results We studied whole proteome sequences of 970 microbial organisms using n-gram frequencies and cross-perplexity employing the Biological Language Modeling Toolkit and Patternix Revelio toolkit. Genus-specific signatures were observed even in a simple unigram distribution. By taking statistical n-gram model of one organism as reference and computing cross-perplexity of all other microbial proteomes with it, cross-perplexity was found to be predictive of branch distance of the phylogenetic tree. For example, a 4-gram model from proteome of Shigellae flexneri 2a, which belongs to the Gammaproteobacteria class showed a self-perplexity of 15.34 while the cross-perplexity of other organisms was in the range of 15.59 to 29.5 and was proportional to their branching distance in the evolutionary tree from S. flexneri. The organisms of this genus, which happen to be pathotypes of E.coli, also have the closest perplexity values with

  12. Strategic planning models in public and non-profit sport organizations

    Directory of Open Access Journals (Sweden)

    ELENA THEAKOU

    2007-01-01

    Full Text Available Strategic planning is widely used by organisations, as itis an integral part of strategy. The present study tackles thetopic of strategic planning as it is developed by public andnon-profit organizations and provides an extensive review ofliterature in the area of the development and role of strategic planning within strategic management and the way it is adopted by public and non-profit organizations. For the purposes of this paper, five models of strategic planning have been discussed with the belief that they describe better the models that can be approached and developed by public and non-profit organizations in the area of sport. This article aims at partly contributing to the theoretical discussion concerning the ability of organizations to integrate and deploy strategic planning. For this study we examined a non-profitsport organization in British Columbia, Canada. The authorspropose that public and non-profit sport organizations shoulddevelop their own model of strategic planning, which mayhelp them to think and act strategically.

  13. Evaluating mountain goat dairy systems for conversion to the organic model, using a multicriteria method.

    Science.gov (United States)

    Mena, Y; Nahed, J; Ruiz, F A; Sánchez-Muñoz, J B; Ruiz-Rojas, J L; Castel, J M

    2012-04-01

    Organic farming conserves natural resources, promotes biodiversity, guarantees animal welfare and obtains healthy products from raw materials through natural processes. In order to evaluate possibilities of increasing organic animal production, this study proposes a farm-scale multicriteria method for assessing the conversion of dairy goat systems to the organic model. In addition, a case study in the Northern Sierra of Seville, southern Spain, is analysed. A consensus of expert opinions and a field survey are used to validate a list of potential indicators and issues for assessing the conversion, which consider not only the European Community regulations for organic livestock farming, but also agroecological principles. As a result, the method includes 56 variables integrated in nine indicators: Nutritional management, Sustainable pasture management, Soil fertility and contamination, Weed and pest control, Disease prevention, Breeds and reproduction, Animal welfare, Food safety and Marketing and management. The nine indicators are finally integrated in a global index named OLPI (Organic Livestock Proximity Index). Application of the method to a case study with 24 goat farms reveals an OLPI value of 46.5% for dairy goat farms located in mountain areas of southern Spain. The aspects that differ most from the agroecological model include soil management, animal nutrition and product marketing. Results of the case study indicate that the proposed method is easy to implement and is useful for quantifying the approximation of conventional farms to an organic model.

  14. Pu-239 organ specific dosimetric model applied to non-human biota

    Science.gov (United States)

    Kaspar, Matthew Jason

    There are few locations throughout the world, like the Maralinga nuclear test site located in south western Australia, where sufficient plutonium contaminate concentration levels exist that they can be utilized for studies of the long-term radionuclide accumulation in non-human biota. The information obtained will be useful for the potential human users of the site while also keeping with international efforts to better understand doses to non-human biota. In particular, this study focuses primarily on a rabbit sample set collected from the population located within the site. Our approach is intended to employ the same dose and dose rate methods selected by the International Commission on Radiological Protection and adapted by the scientific community for similar research questions. These models rely on a series of simplifying assumptions on biota and their geometry; in particular; organisms are treated as spherical and ellipsoidal representations displaying the animal mass and volume. These simplifications assume homogeneity of all animal tissues. In collaborative efforts between Colorado State University and the Australian Nuclear Science and Technology Organisation (ANSTO), we are expanding current knowledge on radionuclide accumulation in specific organs causing organ-specific dose rates, such as Pu-239 accumulating in bone, liver, and lungs. Organ-specific dose models have been developed for humans; however, little has been developed for the dose assessment to biota, in particular rabbits. This study will determine if it is scientifically valid to use standard software, in particular ERICA Tool, as a means to determine organ-specific dosimetry due to Pu-239 accumulation in organs. ERICA Tool is normally applied to whole organisms as a means to determine radiological risk to whole ecosystems. We will focus on the aquatic model within ERICA Tool, as animal organs, like aquatic organisms, can be assumed to lie within an infinite uniform medium. This model would

  15. Sorption of toxic organic compounds on wastewater solids: Mechanism and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L.; Govind, R.; Dobbs, R.A.

    1992-01-01

    Sorption of toxic organic compounds on wastewater solids is an important process in conventional biological wastewater treatment systems. The extent of accumulation of toxic organic compounds by sorption onto wastewater solids not only affects the efficiency of the treatment system, but also impacts the management of wastewater solids. The study is an attempt to propose a mechanism for understanding the sorption phenomenon and to develop a model for sorption on wastewater solids based on the proposed mechanism. It was postulated that sorption was a combination of two processes: adsorption and partitioning. A sorption model was developed for both single component and multicomponent systems. The model was tested using single component experimental isotherm data of eight toxic organic compounds.

  16. Tilt aftereffects in a self-organizing model of the primary visual cortex.

    Science.gov (United States)

    Bednar, J A; Miikkulainen, R

    2000-07-01

    RF-LISSOM, a self-organizing model of laterally connected orientation maps in the primary visual cortex, was used to study the psychological phenomenon known as the tilt aftereffect. The same self-organizing processes that are responsible for the long-term development of the map are shown to result in tilt aftereffects over short timescales in the adult. The model permits simultaneous observation of large numbers of neurons and connections, making it possible to relate high-level phenomena to low-level events, which is difficult to do experimentally. The results give detailed computational support for the long-standing conjecture that the direct tilt aftereffect arises from adaptive lateral interactions between feature detectors. They also make a new prediction that the indirect effect results from the normalization of synaptic efficacies during this process. The model thus provides a unified computational explanation of self-organization and both the direct and indirect tilt aftereffect in the primary visual cortex.

  17. MODELING THE PROCESS OF ASSIMILATION AND OPERATIONALIZATION OF THE CONCEPT OF MARKETING BY ROMANIAN LOCAL ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Luminita Zait

    2015-07-01

    Full Text Available This paper proposes a model that wants to offer some pertinent answers about the process of assimilation and operationalization of the marketing concept in the practice of local organizations in Romania. Considering the reality of organizational practice in Romania, which revealed a lack of consistency in the approach of assimilation and operationalization of the marketing concept, the model tries to capture a range of factors that determine and explain this phenomenon. Reality shows that many Romanian organizations either do not perceive the need and importance of marketing in their activity or assimilate and develop a priori, actions carried out by transnational companies that do not meet the particular context of the Romanian market and / or of internal environment. The model attempts to capture the peculiarities of the process of assimilation and operationalization of the concept of marketing in local organizations and describe the characteristics of each identified organizational structures.

  18. Wave model and self-organization theory of C-space: application in the ergonomics and design

    OpenAIRE

    Kovalev, Y. N.; National Aviation University, Ukraine

    2012-01-01

    Axiomatic wave model and self-organization theory of s– spaceand their application for modeling and optimization of human–machine systems and person–dwelling–environment systems are considered. Axiomatic wave model and self-organization theory of s– spaceand their application for modeling and optimization of human–machine systems and person–dwelling–environment systems are considered.

  19. Partitioning of Organic Ions to Muscle Protein: Experimental Data, Modeling, and Implications for in Vivo Distribution of Organic Ions.

    Science.gov (United States)

    Henneberger, Luise; Goss, Kai-Uwe; Endo, Satoshi

    2016-07-05

    The in vivo partitioning behavior of ionogenic organic chemicals (IOCs) is of paramount importance for their toxicokinetics and bioaccumulation. Among other proteins, structural proteins including muscle proteins could be an important sorption phase for IOCs, because of their high quantity in the human and other animals' body and their polar nature. Binding data for IOCs to structural proteins are, however, severely limited. Therefore, in this study muscle protein-water partition coefficients (KMP/w) of 51 systematically selected organic anions and cations were determined experimentally. A comparison of the measured KMP/w with bovine serum albumin (BSA)-water partition coefficients showed that anionic chemicals sorb more strongly to BSA than to muscle protein (by up to 3.5 orders of magnitude), while cations sorb similarly to both proteins. Sorption isotherms of selected IOCs to muscle protein are linear (i.e., KMP/w is concentration independent), and KMP/w is only marginally influenced by pH value and salt concentration. Using the obtained data set of KMP/w a polyparameter linear free energy relationship (PP-LFER) model was established. The derived equation fits the data well (R(2) = 0.89, RMSE = 0.29). Finally, it was demonstrated that the in vitro measured KMP/w values of this study have the potential to be used to evaluate tissue-plasma partitioning of IOCs in vivo.

  20. Optimising the anaerobic co-digestion of urban organic waste using dynamic bioconversion mathematical modelling.

    Science.gov (United States)

    Fitamo, T; Boldrin, A; Dorini, G; Boe, K; Angelidaki, I; Scheutz, C

    2016-12-01

    Mathematical anaerobic bioconversion models are often used as a convenient way to simulate the conversion of organic materials to biogas. The aim of the study was to apply a mathematical model for simulating the anaerobic co-digestion of various types of urban organic waste, in order to develop strategies for controlling and optimising the co-digestion process. The model parameters were maintained in the same way as the original dynamic bioconversion model, albeit with minor adjustments, to simulate the co-digestion of food and garden waste with mixed sludge from a wastewater treatment plant in a continuously stirred tank reactor. The model's outputs were validated with experimental results obtained in thermophilic conditions, with mixed sludge as a single substrate and urban organic waste as a co-substrate at hydraulic retention times of 30, 20, 15 and 10 days. The predicted performance parameter (methane productivity and yield) and operational parameter (concentration of ammonia and volatile fatty acid) values were reasonable and displayed good correlation and accuracy. The model was later applied to identify optimal scenarios for an urban organic waste co-digestion process. The simulation scenario analysis demonstrated that increasing the amount of mixed sludge in the co-substrate had a marginal effect on the reactor performance. In contrast, increasing the amount of food waste and garden waste resulted in improved performance.

  1. MI-QSAR models for prediction of corneal permeability of organic compounds

    Institute of Scientific and Technical Information of China (English)

    Cheng CHEN; Jie YANG

    2006-01-01

    Aim: To derive a theoretical model for the prediction of corneal permeability of miscellaneous organic compounds in drug design. Methods: A training set of 28structurally diverse compounds was used to build up the membrane-interaction quantitative structure-activity relationship (MI-QSAR) models. Intermolecular and intramolecular solute descriptors were computed using molecular mechanics,molecular dynamics simulations and quantum chemistry. The QSAR models were optimized using multidimensional linear regression fitting and a stepwise method.A test set of 8 compounds was evaluated using the models as part of a validation process. Results: Significant MI-QSAR models (R=0.976, S=0.1301, F=70.957) of corneal permeability of organic compounds were constructed. Corneal permeability was found to depend upon the sum of net atomic charges of hydrogen atoms attached to the heteroatoms (N, O), the sum of the absolute values of the net atomic charges of oxygen and nitrogen atoms, the principal moment of inertia (X),the Connolly accessible area and the conformational flexibility of the solute-membrane complex. Conclusion: The MI-QSAR models indicated that the corneal permeability of organic molecules was not only influenced by the organic solutes themselves, but also related to the properties of the solute-membrane complex,that is, the interactions of the molecule with the phospholipid-rich regions of cellular membranes.

  2. Modeling the multiday evolution and aging of secondary organic aerosol during MILAGRO 2006.

    Science.gov (United States)

    Dzepina, Katja; Cappa, Christopher D; Volkamer, Rainer M; Madronich, Sasha; Decarlo, Peter F; Zaveri, Rahul A; Jimenez, Jose L

    2011-04-15

    In this study, we apply several recently proposed models to the evolution of secondary organic aerosols (SOA) and organic gases advected from downtown Mexico City at an altitude of ∼3.5 km during three days of aging, in a way that is directly comparable to simulations in regional and global models. We constrain the model with and compare its results to available observations. The model SOA formed from oxidation of volatile organic compounds (V-SOA) when using a non-aging SOA parameterization cannot explain the observed SOA concentrations in aged pollution, despite the increasing importance of the low-NO(x) channel. However, when using an aging SOA parameterization, V-SOA alone is similar to the regional aircraft observations, highlighting the wide diversity in current V-SOA formulations. When the SOA formed from oxidation of semivolatile and intermediate volatility organic vapors (SI-SOA) is computed following Robinson et al. (2007) the model matches the observed SOA mass, but its O/C is ∼2× too low. With the parameterization of Grieshop et al. (2009), the total SOA mass is ∼2× too high, but O/C and volatility are closer to the observations. Heating or dilution cause the evaporation of a substantial fraction of the model SOA; this fraction is reduced by aging although differently for heating vs dilution. Lifting of the airmass to the free-troposphere during dry convection substantially increases SOA by condensation of semivolatile vapors; this effect is reduced by aging.

  3. Predictive model of blood-brain barrier penetration of organic compounds

    Institute of Scientific and Technical Information of China (English)

    Xiao-lei MA; Cheng CHEN; Jie YANG

    2005-01-01

    Aim: To build up a theoretical model of organic compounds for the prediction of the activity of small molecules through the blood-brain barrier (BBB) in drug design. Methods: A training set of 37 structurally diverse compounds was used to construct quantitative structure-activity relationship (QSAR) models. Intermolecular and intramolecular solute descriptors were calculated using molecular mechanics, molecular dynamics simulations, quantum chemistry and so on. The QSAR models were optimized using multidimensional linear regression fitting and stepwise method. A test set of 8 compounds was evaluated using the models as part of a validation process. Results: Significant QSAR models (R=0.955, s=0.232) of the BBB penetration of organic compounds were constructed. BBB penetrationwas found to depend upon the polar surface area, the octanol/water partition coefficient, Balaban Index, the strength of a small molecule to combine with the membrane-water complex, and the changeability of the structure of a solute-membrane-water complex. Conclusion: The QSAR models indicate that the distribution of organic molecules through BBB is not only influenced by organic solutes themselves, but also relates to the properties of the solute-membrane-water complex, that is, interactions of the molecule with the phospholipid-rich regions of cellular membranes.

  4. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

    Science.gov (United States)

    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  5. PENERAPAN MODEL PEMBELAJARAN ADVANCE ORGANIZER BERVISI SETS TERHADAP PENINGKATAN PENGUASAAN KONSEP KIMIA

    Directory of Open Access Journals (Sweden)

    Ilam Pratitis

    2015-11-01

    Full Text Available This study aims to determine the effect of the application of learning model with advance organizer envisions SETS to increase mastery of chemistry concepts in the high school in Semarang on buffer solution material. The design used in this research is the design of the control group non equivalent. Sampling was conducted with a purposive sampling technique, and obtained a XI 6 science grade as experimental class and class XI 5 science grade as control class. Data collection method used is the method of documentation, testing, observation, and questionnaires. The results showed that the average cognitive achievement of experimental class was 84, while the control class was 82. The result of data analysis showed that the effect of the application of learning model with advance organizer envisions SETS was able to increase the mastery of chemical concepts of 4%, with a correlation rate of 0.2. Based on the results, it can be concluded that the learning model with advance organizer envisions SETS had positive effect of increasing mastery of the concept of chemistry on buffer solution material. The advice given is learning model with organizer envisions SETS should also be applied to other chemistry materials. This is of course accompanied by a change in order to suit the needs of its effect on learning outcomes in the form of concept mastery of chemistry to be more increased.Keywords: Advance Organizer, Buffer Solution, Concept Mastery, SETS

  6. Multi-Organ Contribution to the Metabolic Plasma Profile Using Hierarchical Modelling.

    Directory of Open Access Journals (Sweden)

    Frida Torell

    Full Text Available Hierarchical modelling was applied in order to identify the organs that contribute to the levels of metabolites in plasma. Plasma and organ samples from gut, kidney, liver, muscle and pancreas were obtained from mice. The samples were analysed using gas chromatography time-of-flight mass spectrometry (GC TOF-MS at the Swedish Metabolomics centre, Umeå University, Sweden. The multivariate analysis was performed by means of principal component analysis (PCA and orthogonal projections to latent structures (OPLS. The main goal of this study was to investigate how each organ contributes to the metabolic plasma profile. This was performed using hierarchical modelling. Each organ was found to have a unique metabolic profile. The hierarchical modelling showed that the gut, kidney and liver demonstrated the greatest contribution to the metabolic pattern of plasma. For example, we found that metabolites were absorbed in the gut and transported to the plasma. The kidneys excrete branched chain amino acids (BCAAs and fatty acids are transported in the plasma to the muscles and liver. Lactic acid was also found to be transported from the pancreas to plasma. The results indicated that hierarchical modelling can be utilized to identify the organ contribution of unknown metabolites to the metabolic profile of plasma.

  7. A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2008-03-01

    Full Text Available Tropospheric aerosols contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behaviour. By means of activity coefficients, non-ideal behaviour can be taken into account. We present here a thermodynamic model named AIOMFAC (Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients that is able to calculate activity coefficients covering inorganic, organic, and organic–inorganic interactions in aqueous solutions over a wide concentration range. This model is based on the activity coefficient model LIFAC by Yan et al. (1999 that we modified and reparametrised to better describe atmospherically relevant conditions and mixture compositions. Focusing on atmospheric applications we considered H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO42− as cations and anions and a wide range of alcohols/polyols composed of the functional groups CHn and OH as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are well represented up to high ionic strength. Most notably, a semi-empirical middle-range parametrisation of direct organic–inorganic interactions in alcohol + water + salt solutions strongly improves the agreement between experimental and modelled activity coefficients. At room temperature, this novel thermodynamic model offers the possibility to compute equilibrium relative humidities, gas/particle partitioning and liquid–liquid phase separations with high accuracy. In further studies, other organic functional groups will be introduced. The model framework is not restricted to specific ions or organic compounds and is therefore

  8. Organization of pattern information in the pattern based software development: A POMSDP model

    Institute of Scientific and Technical Information of China (English)

    TANG Yong; LIU Ri-guang; WANG Yan

    2008-01-01

    Focused on the lack of proper organization for patterns in the development of pattern based software, a POMSDP model with layered tree structure for organizing patterns during the process of development was put forward. The model and its interrelated concepts were strictly defined and introduced by applying the theory of set, symbolic logic and pattern, which ensures the correctness, maturity and expansibility of the model. The expansibility of the model was discussed mainly. The basic realization and the application in the automatic que-ry system were presented. Based on the existing software development methods, the POMSDP model resolves the problem of chaos in the application of patterns, strengthens the controllability of the system, and facilitates the improvement, maintenance, expansion, and especially the reengineering of the software system.

  9. Estimation of Separation of Electrolytes and Organic Compounds by Nanofiltration Membranes Using an Irreversible Thermodynamic Model

    Institute of Scientific and Technical Information of China (English)

    PallabGhosh

    2003-01-01

    Nanofiltration separation has become a popular technique for removing large organic molecules and inorganic substances from water. It is achieved by a combination of three mechanisms: electrostatic repulsion,sieving and diffusion. In the present work, a model based on irreversible thermodynamics is extended and used to estimate rejection of inorganic salts and organic substances. Binary systems are modeled, where the feed contains an ion that is much less permeable to the membrane as compared with the other ion. The two model parameters are estimated by fitting the model to the experimental data. Variation of these parameters with the composition of the feed is described by an empirical correlation. This work attempts to describe transport through the nanofiltration membranes bv a simple model.

  10. Modeling the Free Carrier Recombination Kinetics in PTB7:PCBM Organic Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Oosterhout, Stefan D.; Ferguson, Andrew J.; Larson, Bryon W.; Olson, Dana C.; Kopidakis, Nikos

    2016-11-03

    Currently the exact recombination mechanism of free carriers in organic photovoltaic (OPV) devices is poorly understood. Often a reduced Langevin model is used to describe the decay behavior of electrons and holes. Here we propose a novel, simple kinetic model that accurately describes the decay behavior of free carriers in the PTB7:PCBM organic photovoltaic blend. This model needs to only take into account free and trapped holes in the polymer, and free electrons in the fullerene, to accurately describe the recombination behavior of free carriers as measured by time-resolved microwave conductivity (TRMC). The model is consistent for different PTB7:PCBM blend ratios and spans a light intensity range of over 3 orders of magnitude. The model demonstrates that dark carriers exist in the polymer and interact with photoinduced charge carriers, and that the trapping and detrapping rates of the holes are of high importance to the overall carrier lifetime.

  11. Effects of Interactive Function Forms and Refractoryperiod in a Self-Organized Critical Model Based on Neural Networks

    Institute of Scientific and Technical Information of China (English)

    ZHOULi-Ming; CHENTian-Lun

    2004-01-01

    Based on the standard self-organizing map neural network model and an integrate-and-fire mechanism, we investigate the effect of the nonlinear interactive function on the self-organized criticality in our model. Based on the sewe also investigate the effect of the refractoryperiod on the self-organized criticality of the system.

  12. Effects of Interactive Function Forms and Refractoryperiod in a Self-Organized Critical Model Based on Neural Networks

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Ming; CHEN Tian-Lun

    2004-01-01

    Based on the standard self-organizing map neural network model and an integrate-and-tire mechanism, we investigate the effect of the nonlinear interactive function on the self-organized criticality in our model. Based on these we also investigate the effect of the refractoryperiod on the self-organized criticality of the system.

  13. A secondary organic aerosol formation model considering successive oxidation aging and kinetic condensation of organic compounds: global scale implications

    Directory of Open Access Journals (Sweden)

    F. Yu

    2011-02-01

    Full Text Available The widely used two-product secondary organic aerosol (SOA formation model has been extended in this study to consider the volatility changes of secondary organic gases (SOG arising from the aging process as well as the kinetic condensation of low volatile SOG (LV-SOG. In addition to semi-volatile SOG (SV-SOG with saturation vapor pressure at 290 K (C*290 in the range of ~3 ppt–3 ppb and medium-volatile SOG (MV-SOG with C*290 in the range of ~0.3–300 ppb, we add a third component representing LV-SOG with C*290 below ~3 ppt and design a scheme to transfer MV-SOG to SV-SOG and SV-SOG to LV-SOG associated with oxidation aging. This extended SOA formation model has been implemented in a global aerosol model (GEOS-Chem and the co-condensation of H2SO4 and LV-SOG on pre-existing particles is explicitly simulated. We show that, over many parts of the continents, LV-SOG concentrations are generally a factor of ~2–20 higher than those of H2SO4 and the kinetic condensation of LV-SOG significantly enhances particle growth rates. Comparisons of the simulated and observed evolution of particle size distributions at a boreal forest site (Hyytiälä, Finland clearly show that LV-SOG condensation is critical in order to bring the simulations closer to the observations. With the new SOA formation scheme, annual mean SOA mass increases by a factor of 2–10 in many parts of the boundary layer and reaches above 0.5 μg m−3 in most parts of the main continents, improving the agreement with aerosol mass spectrometer (AMS SOA measurements. While the new scheme generally decreases the concentration of condensation nuclei larger than 10 nm by 3–30% in the lower boundary layer as a result of enhanced surface area and reduced nucleation rates, it substantially increases the concentration of cloud condensation nuclei at a

  14. A self-organizing power system stabilizer using Fuzzy Auto-Regressive Moving Average (FARMA) model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.M.; Moon, U.C. [Seoul National Univ. (Korea, Republic of). Electrical Engineering Dept.; Lee, K.Y. [Pennsylvania State Univ., University Park, PA (United States). Electrical Engineering Dept.

    1996-06-01

    This paper presents a self-organizing power system stabilizer (SOPSS) which use the Fuzzy Auto-Regressive Moving Average (FARMA) model. The control rules and the membership functions of the proposed logic controller are generated automatically without using any plant model. The generated rules are stored in the fuzzy rule space and updated on-line by a self-organizing procedure. To show the effectiveness of the proposed controller, comparison with a conventional controller for one-machine infinite-bus system is presented.

  15. Microscopic modeling of magnetic-field effects on charge transport in organic semiconductors

    Science.gov (United States)

    Schellekens, A. J.; Wagemans, W.; Kersten, S. P.; Bobbert, P. A.; Koopmans, B.

    2011-08-01

    The stochastic Liouville equation is applied to the field of organic magnetoresistance to perform detailed microscopic calculations on the different proposed models. By adapting this equation, the influence of a magnetic field on the current in bipolaron, electron-hole pair, and triplet models is calculated. The simplicity and wide applicability of the stochastic Liouville equation makes it a powerful tool for interpreting experimental results on magnetoresistance measurements in organic semiconductors. New insights are gained on the influence of hopping rates and disorder on the magnetoresistance.

  16. Modeling the Self-organized Critical Behavior of the Plasma Sheet Reconnection Dynamics

    Science.gov (United States)

    Klimas, Alex; Uritsky, Vadim; Baker, Daniel

    2006-01-01

    Analyses of Polar UVI auroral image data reviewed in our other presentation at this meeting (V. Uritsky, A. Klimas) show that bright night-side high-latitude UV emissions exhibit so many of the key properties of systems in self-organized criticality (SOC) that an alternate interpretation has become virtually impossible. It is now necessary to find and model the source of this behavior. We note that the most common models of self-organized criticality are numerical sandpiles. These are, at root, models that govern the transport of some quantity from a region where it is loaded to another where it is unloaded. Transport is enabled by the excitation of a local threshold instability; it is intermittent and bursty, and it exhibits a number of scale-free statistical properties. Searching for a system in the magnetosphere that is analogous and that, in addition, is known to produce auroral signatures, we focus on the reconnection dynamics of the plasma sheet. In our previous work, a driven reconnection model has been constructed and has been under study. The transport of electromagnetic (primarily magnetic) energy carried by the Poynting flux into the reconnection region of the model has been examined. All of the analysis techniques, and more, that have been applied to the auroral image data have also been applied to this Poynting flux. Here, we report new results showing that this model also exhibits so many of the key properties of systems in self-organized criticality that an alternate interpretation is implausible. Further, we find a strong correlation between these key properties of the model and those of the auroral UV emissions. We suggest that, in general, the driven reconnection model is an important step toward a realistic plasma physical model of self-organized criticality and we conclude, more specifically, that it is also a step in the right direction toward modeling the multiscale reconnection dynamics of the magnetotail.

  17. Modeling the Self-organized Critical Behavior of Earth's Plasma Sheet Reconnection Dynamics

    Science.gov (United States)

    Klimas, Alexander J.

    2006-01-01

    Analyses of Polar UVI auroral image data show that bright night-side high-latitude W emissions exhibit so many of the key properties of systems in self-organized criticality that an alternate interpretation has become virtually impossible. These analyses will be reviewed. It is now necessary to find and model the source of this behavior. We note that the most common models of self-organized criticality are numerical sandpiles. These are, at root, models that govern the transport of some quantity from a region where it is loaded to another where it is unloaded. Transport is enabled by the excitation of a local threshold instability; it is intermittent and bursty, and it exhibits a number of scale-free statistical properties. Searching for a system in the magnetosphere that is analogous and that, in addition, is known to produce auroral signatures, we focus on the reconnection dynamics of the magnetotail plasma sheet. In our previous work, a driven reconnection model has been constructed and has been under study. The transport of electromagnetic (primarily magnetic) energy carried by the Poynting flux into the reconnection region of the model has been examined. All of the analysis techniques (and more) that have been applied to the auroral image data have also been applied to this Poynting flux. New results will be presented showing that this model also exhibits so many of the key properties of systems in self-organized criticality that an alternate interpretation is implausible. A strong correlation between these key properties of the model and those of the auroral UV emissions will be demonstrated. We suggest that, in general, the driven reconnection model is an important step toward a realistic plasma physical model of self-organized criticality and we conclude, more specifically, that it is also a step in the right direction toward modeling the multiscale reconnection dynamics of the magnetotail.

  18. Mathematical model of organic substrate degradation in solid waste windrow composting.

    Science.gov (United States)

    Seng, Bunrith; Kristanti, Risky Ayu; Hadibarata, Tony; Hirayama, Kimiaki; Katayama-Hirayama, Keiko; Kaneko, Hidehiro

    2016-01-01

    Organic solid waste composting is a complex process that involves many coupled physical, chemical and biological mechanisms. To understand this complexity and to ease in planning, design and management of the composting plant, mathematical model for simulation is usually applied. The aim of this paper is to develop a mathematical model of organic substrate degradation and its performance evaluation in solid waste windrow composting system. The present model is a biomass-dependent model, considering biological growth processes under the limitation of moisture, oxygen and substrate contents, and temperature. The main output of this model is substrate content which was divided into two categories: slowly and rapidly degradable substrates. To validate the model, it was applied to a laboratory scale windrow composting of a mixture of wood chips and dog food. The wastes were filled into a cylindrical reactor of 6 cm diameter and 1 m height. The simulation program was run for 3 weeks with 1 s stepwise. The simulated results were in reasonably good agreement with the experimental results. The MC and temperature of model simulation were found to be matched with those of experiment, but limited for rapidly degradable substrates. Under anaerobic zone, the degradation of rapidly degradable substrate needs to be incorporated into the model to achieve full simulation of a long period static pile composting. This model is a useful tool to estimate the changes of substrate content during composting period, and acts as a basic model for further development of a sophisticated model.

  19. Predicting the acute neurotoxicity of diverse organic solvents using probabilistic neural networks based QSTR modeling approaches.

    Science.gov (United States)

    Basant, Nikita; Gupta, Shikha; Singh, Kunwar P

    2016-03-01

    Organic solvents are widely used chemicals and the neurotoxic properties of some are well established. In this study, we established nonlinear qualitative and quantitative structure-toxicity relationship (STR) models for predicting neurotoxic classes and neurotoxicity of structurally diverse solvents in rodent test species following OECD guideline principles for model development. Probabilistic neural network (PNN) based qualitative and generalized regression neural network (GRNN) based quantitative STR models were constructed using neurotoxicity data from rat and mouse studies. Further, interspecies correlation based quantitative activity-activity relationship (QAAR) and global QSTR models were also developed using the combined data set of both rodent species for predicting the neurotoxicity of solvents. The constructed models were validated through deriving several statistical coefficients for the test data and the prediction and generalization abilities of these models were evaluated. The qualitative STR models (rat and mouse) yielded classification accuracies of 92.86% in the test data sets, whereas, the quantitative STRs yielded correlation (R(2)) of >0.93 between the measured and model predicted toxicity values in both the test data (rat and mouse). The prediction accuracies of the QAAR (R(2) 0.859) and global STR (R(2) 0.945) models were comparable to those of the independent local STR models. The results suggest the ability of the developed QSTR models to reliably predict binary neurotoxicity classes and the endpoint neurotoxicities of the structurally diverse organic solvents.

  20. Species sensitivity distribution for chlorpyrifos to aquatic organisms: Model choice and sample size.

    Science.gov (United States)

    Zhao, Jinsong; Chen, Boyu

    2016-03-01

    Species sensitivity distribution (SSD) is a widely used model that extrapolates the ecological risk to ecosystem levels from the ecotoxicity of a chemical to individual organisms. However, model choice and sample size significantly affect the development of the SSD model and the estimation of hazardous concentrations at the 5th centile (HC5). To interpret their effects, the SSD model for chlorpyrifos, a widely used organophosphate pesticide, to aquatic organisms is presented with emphases on model choice and sample size. Three subsets of median effective concentration (EC50) with different sample sizes were obtained from ECOTOX and used to build SSD models based on parametric distribution (normal, logistic, and triangle distribution) and nonparametric bootstrap. The SSD models based on the triangle distribution are superior to the normal and logistic distributions according to several goodness-of-fit techniques. Among all parametric SSD models, the one with the largest sample size based on the triangle distribution gives the most strict HC5 with 0.141μmolL(-1). The HC5 derived from the nonparametric bootstrap is 0.159μmol L(-1). The minimum sample size required to build a stable SSD model is 11 based on parametric distribution and 23 based on nonparametric bootstrap. The study suggests that model choice and sample size are important sources of uncertainty for application of the SSD model. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. In silico model for predicting soil organic carbon normalized sorption coefficient (K(OC)) of organic chemicals.

    Science.gov (United States)

    Wang, Ya; Chen, Jingwen; Yang, Xianhai; Lyakurwa, Felichesmi; Li, Xuehua; Qiao, Xianliang

    2015-01-01

    As a kind of in silico method, the methodology of quantitative structure-activity relationship (QSAR) has been shown to be an efficient way to predict soil organic carbon normalized sorption coefficients (KOC) values. In the present study, a total of 824 logKOC values were used to develop and validate a QSAR model for predicting KOC values. The model statistics parameters, adjusted determination coefficient (R(2)adj) of 0.854, the root mean square error (RMSE) of 0.472, the leave-one-out cross-validation squared correlation coefficient (Q(2)LOO) of 0.850, the external validation coefficient Q(2)ext of 0.761 and the RMSEext of 0.558 were obtained, which indicate satisfactory goodness of fit, robustness and predictive ability. The squared Moriguchi octanol-water partition coefficient (MLOGP2) explained 66.5% of the logKOC variance. The applicability domain of the current model has been extended to emerging pollutants like polybrominated diphenyl ethers, perfluorochemicals and heterocyclic toxins. The developed model can be used to predict the compounds with various functional groups including C=C, -C≡C-, -OH, -O-, -CHO, C=O, -C=O(O), -COOH, -C6H5, -NO2, -NH2, -NH-, N-, -N-N-, -NH-C(O)-NH-, -O-C(O)-NH2, -C(O)-NH2, -X(F, Cl, Br, I), -S-, -SH, -S(O)2-, -OS(O)2-, -NH-S(O)2-, (SR)2PH(OR)2 and Si. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Modelling carbon overconsumption and the formation of extracellular particulate organic carbon

    Science.gov (United States)

    Schartau, M.; Engel, A.; Schröter, J.; Thoms, S.; Völker, C.; Wolf-Gladrow, D.

    2007-07-01

    During phytoplankton growth a fraction of dissolved inorganic carbon (DIC) assimilated by phytoplankton is exuded in the form of dissolved organic carbon (DOC), which can be transformed into extracellular particulate organic carbon (POC). A major fraction of extracellular POC is associated with carbon of transparent exopolymer particles (TEP; carbon content = TEPC) that form from dissolved polysaccharides (PCHO). The exudation of PCHO is linked to an excessive uptake of DIC that is not directly quantifiable from utilisation of dissolved inorganic nitrogen (DIN), called carbon overconsumption. Given these conditions, the concept of assuming a constant stoichiometric carbon-to-nitrogen (C:N) ratio for estimating new production of POC from DIN uptake becomes inappropriate. Here, a model of carbon overconsumption is analysed, combining phytoplankton growth with TEPC formation. The model describes two modes of carbon overconsumption. The first mode is associated with DOC exudation during phytoplankton biomass accumulation. The second mode is decoupled from algal growth, but leads to a continuous rise in POC while particulate organic nitrogen (PON) remains constant. While including PCHO coagulation, the model goes beyond a purely physiological explanation of building up carbon rich particulate organic matter (POM). The model is validated against observations from a mesocosm study. Maximum likelihood estimates of model parameters, such as nitrogen- and carbon loss rates of phytoplankton, are determined. The optimisation yields results with higher rates for carbon exudation than for the loss of organic nitrogen. It also suggests that the PCHO fraction of exuded DOC was 63±20% during the mesocosm experiment. Optimal estimates are obtained for coagulation kernels for PCHO transformation into TEPC. Model state estimates are consistent with observations, where 30% of the POC increase was attributed to TEPC formation. The proposed model is of low complexity and is applicable

  3. Modelling carbon overconsumption and the formation of extracellular particulate organic carbon

    Directory of Open Access Journals (Sweden)

    M. Schartau

    2007-01-01

    Full Text Available During phytoplankton growth a fraction of dissolved inorganic carbon (DIC assimilated by phytoplankton is exuded in the form of dissolved organic carbon (DOC, which can be transformed into extracellular particulate organic carbon (POC. A major fraction of extracellular POC is associated with carbon of transparent exopolymer particles (TEP; carbon content = TEPC that form from dissolved polysaccharides (PCHO. The exudation of PCHO is linked to an excessive uptake of DIC that is not directly quantifiable from utilisation of dissolved inorganic nitrogen (DIN, called carbon overconsumption. Given these conditions, the concept of assuming a constant stoichiometric carbon-to-nitrogen (C:N ratio for estimating new production of POC from DIN uptake becomes inappropriate. Here, a model of carbon overconsumption is analysed, combining phytoplankton growth with TEPC formation. The model describes two modes of carbon overconsumption. The first mode is associated with DOC exudation during phytoplankton biomass accumulation. The second mode is decoupled from algal growth, but leads to a continuous rise in POC while particulate organic nitrogen (PON remains constant. While including PCHO coagulation, the model goes beyond a purely physiological explanation of building up carbon rich particulate organic matter (POM. The model is validated against observations from a mesocosm study. Maximum likelihood estimates of model parameters, such as nitrogen- and carbon loss rates of phytoplankton, are determined. The optimisation yields results with higher rates for carbon exudation than for the loss of organic nitrogen. It also suggests that the PCHO fraction of exuded DOC was 63±20% during the mesocosm experiment. Optimal estimates are obtained for coagulation kernels for PCHO transformation into TEPC. Model state estimates are consistent with observations, where 30% of the POC increase was attributed to TEPC formation. The proposed model is of low complexity and is

  4. Modelling carbon overconsumption and the formation of extracellular particulate organic carbon

    Directory of Open Access Journals (Sweden)

    C. Völker

    2007-07-01

    Full Text Available During phytoplankton growth a fraction of dissolved inorganic carbon (DIC assimilated by phytoplankton is exuded in the form of dissolved organic carbon (DOC, which can be transformed into extracellular particulate organic carbon (POC. A major fraction of extracellular POC is associated with carbon of transparent exopolymer particles (TEP; carbon content = TEPC that form from dissolved polysaccharides (PCHO. The exudation of PCHO is linked to an excessive uptake of DIC that is not directly quantifiable from utilisation of dissolved inorganic nitrogen (DIN, called carbon overconsumption. Given these conditions, the concept of assuming a constant stoichiometric carbon-to-nitrogen (C:N ratio for estimating new production of POC from DIN uptake becomes inappropriate. Here, a model of carbon overconsumption is analysed, combining phytoplankton growth with TEPC formation. The model describes two modes of carbon overconsumption. The first mode is associated with DOC exudation during phytoplankton biomass accumulation. The second mode is decoupled from algal growth, but leads to a continuous rise in POC while particulate organic nitrogen (PON remains constant. While including PCHO coagulation, the model goes beyond a purely physiological explanation of building up carbon rich particulate organic matter (POM. The model is validated against observations from a mesocosm study. Maximum likelihood estimates of model parameters, such as nitrogen- and carbon loss rates of phytoplankton, are determined. The optimisation yields results with higher rates for carbon exudation than for the loss of organic nitrogen. It also suggests that the PCHO fraction of exuded DOC was 63±20% during the mesocosm experiment. Optimal estimates are obtained for coagulation kernels for PCHO transformation into TEPC. Model state estimates are consistent with observations, where 30% of the POC increase was attributed to TEPC formation. The proposed model is of low complexity and is

  5. Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Mesbahus Saleheen

    2016-05-01

    Full Text Available A physics-based explicit mathematical model for the external voltage-dependent forward dark current in bulk heterojunction (BHJ organic solar cells is developed by considering Shockley-Read-Hall (SRH recombination and solving the continuity equations for both electrons and holes. An analytical model for the external voltage-dependent photocurrent in BHJ organic solar cells is also proposed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs, carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun’s model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The overall net current is calculated considering the actual solar spectrum. The mathematical models are verified by comparing the model calculations with various published experimental results. We analyze the effects of the contact properties, blend compositions, charge carrier transport properties (carrier mobility and lifetime, and cell design on the current-voltage characteristics. The power conversion efficiency of BHJ organic solar cells mostly depends on electron transport properties of the acceptor layer. The results of this paper indicate that improvement of charge carrier transport (both mobility and lifetime and dissociation of bound EHPs in organic blend are critically important to increase the power conversion efficiency of the BHJ solar cells.

  6. Similarity-based search of model organism, disease and drug effect phenotypes

    KAUST Repository

    Hoehndorf, Robert

    2015-02-19

    Background: Semantic similarity measures over phenotype ontologies have been demonstrated to provide a powerful approach for the analysis of model organism phenotypes, the discovery of animal models of human disease, novel pathways, gene functions, druggable therapeutic targets, and determination of pathogenicity. Results: We have developed PhenomeNET 2, a system that enables similarity-based searches over a large repository of phenotypes in real-time. It can be used to identify strains of model organisms that are phenotypically similar to human patients, diseases that are phenotypically similar to model organism phenotypes, or drug effect profiles that are similar to the phenotypes observed in a patient or model organism. PhenomeNET 2 is available at http://aber-owl.net/phenomenet. Conclusions: Phenotype-similarity searches can provide a powerful tool for the discovery and investigation of molecular mechanisms underlying an observed phenotypic manifestation. PhenomeNET 2 facilitates user-defined similarity searches and allows researchers to analyze their data within a large repository of human, mouse and rat phenotypes.

  7. a Quadtree Organization Construction and Scheduling Method for Urban 3d Model Based on Weight

    Science.gov (United States)

    Yao, C.; Peng, G.; Song, Y.; Duan, M.

    2017-09-01

    The increasement of Urban 3D model precision and data quantity puts forward higher requirements for real-time rendering of digital city model. Improving the organization, management and scheduling of 3D model data in 3D digital city can improve the rendering effect and efficiency. This paper takes the complexity of urban models into account, proposes a Quadtree construction and scheduling rendering method for Urban 3D model based on weight. Divide Urban 3D model into different rendering weights according to certain rules, perform Quadtree construction and schedule rendering according to different rendering weights. Also proposed an algorithm for extracting bounding box extraction based on model drawing primitives to generate LOD model automatically. Using the algorithm proposed in this paper, developed a 3D urban planning&management software, the practice has showed the algorithm is efficient and feasible, the render frame rate of big scene and small scene are both stable at around 25 frames.

  8. Snpdat: Easy and rapid annotation of results from de novo snp discovery projects for model and non-model organisms

    Directory of Open Access Journals (Sweden)

    Doran Anthony G

    2013-02-01

    Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs are the most abundant genetic variant found in vertebrates and invertebrates. SNP discovery has become a highly automated, robust and relatively inexpensive process allowing the identification of many thousands of mutations for model and non-model organisms. Annotating large numbers of SNPs can be a difficult and complex process. Many tools available are optimised for use with organisms densely sampled for SNPs, such as humans. There are currently few tools available that are species non-specific or support non-model organism data. Results Here we present SNPdat, a high throughput analysis tool that can provide a comprehensive annotation of both novel and known SNPs for any organism with a draft sequence and annotation. Using a dataset of 4,566 SNPs identified in cattle using high-throughput DNA sequencing we demonstrate the annotations performed and the statistics that can be generated by SNPdat. Conclusions SNPdat provides users with a simple tool for annotation of genomes that are either not supported by other tools or have a small number of annotated SNPs available. SNPdat can also be used to analyse datasets from organisms which are densely sampled for SNPs. As a command line tool it can easily be incorporated into existing SNP discovery pipelines and fills a niche for analyses involving non-model organisms that are not supported by many available SNP annotation tools. SNPdat will be of great interest to scientists involved in SNP discovery and analysis projects, particularly those with limited bioinformatics experience.

  9. New insights into the organic carbon export in the Mediterranean Sea from 3-D modeling

    Directory of Open Access Journals (Sweden)

    A. Guyennon

    2015-04-01

    Full Text Available The Mediterranean Sea is one of the most oligotrophic regions of the oceans, and nutrients have been shown to limit both phytoplankton and bacterial activities. This has direct implications on the stock of dissolved organic carbon (DOC, whose high variability has already been well-documented even if measurements are still sparse and are associated with important uncertainties. We here propose a Mediterranean Basin-scale view of the export of organic carbon, under its dissolved and particulate forms. For this purpose, we have used a coupled model combining a mechanistic biogeochemical model (Eco3M-MED and a high-resolution (eddy-resolving hydrodynamic simulation (NEMO-MED12. This is the first Basin-scale application of the biogeochemical model Eco3M-MED and is shown to reproduce the main spatial and seasonal biogeochemical characteristics of the Mediterranean Sea. Model estimations of carbon export are of the same order of magnitude as estimations from in situ observations, and their respective spatial patterns are consistent with each other. As for surface chlorophyll, nutrient concentrations, and productivity, strong differences between the Western and Eastern Basins are evidenced by the model for organic carbon export, with only 39% of organic carbon (particulate and dissolved export taking place in the Western Basin. The major result is that except for the Alboran Sea, dissolved organic carbon (DOC contribution to organic carbon export is higher than that of particulate (POC in the whole Basin, especially in the Eastern Basin. This paper also investigates the seasonality of DOC and POC exports as well as the differences in the processes involved in DOC and POC exports.

  10. Evolution of circadian organization in vertebrates

    Directory of Open Access Journals (Sweden)

    M. Menaker

    1997-03-01

    Full Text Available Circadian organization means the way in which the entire circadian system above the cellular level is put together physically and the principles and rules that determine the interactions among its component parts which produce overt rhythms of physiology and behavior. Understanding this organization and its evolution is of practical importance as well as of basic interest. The first major problem that we face is the difficulty of making sense of the apparently great diversity that we observe in circadian organization of diverse vertebrates. Some of this diversity falls neatly into place along phylogenetic lines leading to firm generalizations: i in all vertebrates there is a "circadian axis" consisting of the retinas, the pineal gland and the suprachiasmatic nucleus (SCN, ii in many non-mammalian vertebrates of all classes (but not in any mammals the pineal gland is both a photoreceptor and a circadian oscillator, and iii in all non-mammalian vertebrates (but not in any mammals there are extraretinal (and extrapineal circadian photoreceptors. An interesting explanation of some of these facts, especially the differences between mammals and other vertebrates, can be constructed on the assumption that early in their evolution mammals passed through a "nocturnal bottleneck". On the other hand, a good deal of the diversity among the circadian systems of vertebrates does not fall neatly into place along phylogenetic lines. In the present review we will consider how we might better understand such "phylogenetically incoherent" diversity and what sorts of new information may help to further our understanding of the evolution of circadian organization in vertebrates

  11. Ethical models in bioethics: theory and application in organ allocation policies.

    Science.gov (United States)

    Petrini, C

    2010-12-01

    Policies for allocating organs to people awaiting a transplant constitute a major ethical challenge. First and foremost, they demand balance between the principles of beneficence and justice, but many other ethically relevant principles are also involved: autonomy, responsibility, equity, efficiency, utility, therapeutic outcome, medical urgency, and so forth. Various organ allocation models can be developed based on the hierarchical importance assigned to a given principle over the others, but none of the principles should be completely disregarded. An ethically acceptable organ allocation policy must therefore be in conformity, to a certain extent, with the requirements of all the principles. Many models for organ allocation can be derived. The utilitarian model aims to maximize benefits, which can be of various types on a social or individual level, such as the number of lives saved, prognosis, and so forth. The prioritarian model favours the neediest or those who suffer most. The egalitarian model privileges equity and justice, suggesting that all people should have an equal opportunity (casual allocation) or priority should be given to those who have been waiting longer. The personalist model focuses on each individual patient, attempting to mesh together all the various aspects affecting the person: therapeutic needs (urgency), fairness, clinical outcomes, respect for persons. In the individualistic model the main element is free choice and the system of opting-in is privileged. Contrary to the individualistic model, the communitarian model identities in the community the fundamental elements for the legitimacy of choices: therefore, the system of opting-out is privileged. This article does not aim at suggesting practical solutions. Rather, it furnishes to decision makers an overview on the possible ethical approach to this matter.

  12. Allometric scaling and cell ratios in multi-organ in vitro models of human metabolism

    Directory of Open Access Journals (Sweden)

    Nadia eUcciferri

    2014-12-01

    Full Text Available Intelligent in vitro models able to recapitulate the physiological interactions between tissues in the body have enormous potential as they enable detailed studies on specific two-way or higher order tissue communication. These models are the first step towards building an integrated picture of systemic metabolism and signalling in physiological or pathological conditions. However the rational design of in vitro models of cell-cell or cell-tissue interaction is difficult as quite often cell culture experiments are driven by the device used, rather than by design considerations. Indeed very little research has been carried out on in vitro models of metabolism connecting different cell or tissue types in a physiologically and metabolically relevant manner. Here we analyse the physiologic relationship between cells, cell metabolism and exchange in the human body using allometric rules, downscaling them to an organ-on-a plate device. In particular, in order to establish appropriate cell ratios in the system in a rational manner, two different allometric scaling models (Cell Number Scaling Model, CNSM, and Metabolic and Surface Scaling model, MSSM are proposed and applied to a two compartment model of hepatic-vascular metabolic cross-talk. The theoretical scaling studies illustrate that the design and hence relevance of multi-organ models is principally determined by experimental constraints. Two experimentally feasible model configurations are then implemented in a multi-compartment organ-on-a plate device. An analysis of the metabolic response of the two configurations demonstrates that their glucose and lipid balance is quite different, with only one of the two models recapitulating physiological-like homeostasis. In conclusion, not only do cross-talk and physical stimuli play an important role in in vitro models, but the numeric relationship between cells is also crucial to recreate in vitro interactions which can be extrapolated to the in vivo

  13. Global distribution and climate forcing of marine organic aerosol – Part 1: Model improvements and evaluation

    Directory of Open Access Journals (Sweden)

    N. Meskhidze

    2011-07-01

    Full Text Available Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR's Community Atmosphere Model (CAM5 with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7. Emissions of marine primary organic aerosols (POA, phytoplankton-produced isoprene- and monoterpenes-derived secondary organic aerosols (SOA and methane sulfonate (MS are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr−1, for the Gantt et al. (2011 and Vignati et al. (2010 emission parameterizations, respectively. Marine sources of SOA and particulate MS (containing both sulfur and carbon atoms contribute an additional 0.2 and 5.1 Tg yr−1, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ng m−3, with values up to 400 ng m−3 over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM with POA concentrations from the two emission parameterizations shows that both Gantt et al. (2011 and Vignati et al. (2010 formulations are able to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011 parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN. The largest increases (up to 20 % in CCN (at a supersaturation (S of 0.2 % number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming marine organics are internally-mixed with sea-salt provides

  14. Global distribution and climate forcing of marine organic aerosol - Part 1: Model improvements and evaluation

    Science.gov (United States)

    Meskhidze, N.; Xu, J.; Gantt, B.; Zhang, Y.; Nenes, A.; Ghan, S. J.; Liu, X.; Easter, R.; Zaveri, R.

    2011-07-01

    Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR)'s Community Atmosphere Model (CAM5) with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7). Emissions of marine primary organic aerosols (POA), phytoplankton-produced isoprene- and monoterpenes-derived secondary organic aerosols (SOA) and methane sulfonate (MS-) are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr-1, for the Gantt et al. (2011) and Vignati et al. (2010) emission parameterizations, respectively. Marine sources of SOA and particulate MS- (containing both sulfur and carbon atoms) contribute an additional 0.2 and 5.1 Tg yr-1, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ng m-3, with values up to 400 ng m-3 over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM) with POA concentrations from the two emission parameterizations shows that both Gantt et al. (2011) and Vignati et al. (2010) formulations are able to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011) parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN). The largest increases (up to 20 %) in CCN (at a supersaturation (S) of 0.2 %) number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming marine organics are internally-mixed with sea-salt provides diverse results with increase and decrease in the concentration of CCN over different parts of

  15. Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation

    Science.gov (United States)

    Meskhidze, N.; Xu, J.; Gantt, B.; Zhang, Y.; Nenes, A.; Ghan, S. J.; Liu, X.; Easter, R.; Zaveri, R.

    2011-11-01

    Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR)'s Community Atmosphere Model (CAM5) with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7). Emissions of marine primary organic aerosols (POA), phytoplankton-produced isoprene- and monoterpenes-derived secondary organic aerosols (SOA) and methane sulfonate (MS-) are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr-1, for the Gantt et al. (2011) and Vignati et al. (2010) emission parameterizations, respectively. Marine sources of SOA and particulate MS- (containing both sulfur and carbon atoms) contribute an additional 0.2 and 5.1 Tg yr-1, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ng m-3, with values up to 400 ng m-3 over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM) with POA concentrations from the two emission parameterizations shows that despite revealed discrepancies (often more than a factor of 2), both Gantt et al. (2011) and Vignati et al. (2010) formulations are able to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011) parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN). The largest increases (up to 20%) in CCN (at a supersaturation (S) of 0.2%) number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming marine organics are internally-mixed with sea-salt provides diverse results with increases

  16. Can government be self-organized? A mathematical model of the collective social organization of ancient Teotihuacan, central Mexico.

    Directory of Open Access Journals (Sweden)

    Tom Froese

    Full Text Available Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city's origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city's hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city's eventual disintegration.

  17. Can Government Be Self-Organized? A Mathematical Model of the Collective Social Organization of Ancient Teotihuacan, Central Mexico

    Science.gov (United States)

    Froese, Tom; Gershenson, Carlos; Manzanilla, Linda R.

    2014-01-01

    Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city’s origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city’s hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city’s eventual disintegration. PMID:25303308

  18. Can government be self-organized? A mathematical model of the collective social organization of ancient Teotihuacan, central Mexico.

    Science.gov (United States)

    Froese, Tom; Gershenson, Carlos; Manzanilla, Linda R

    2014-01-01

    Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city's origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city's hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city's eventual disintegration.

  19. A self-organized internal models architecture for coding sensory-motor schemes

    Directory of Open Access Journals (Sweden)

    Esaú eEscobar Juárez

    2016-04-01

    Full Text Available Cognitive robotics research draws inspiration from theories and models on cognition, as conceived by neuroscience or cognitive psychology, to investigate biologically plausible computational models in artificial agents. In this field, the theoretical framework of Grounded Cognition provides epistemological and methodological grounds for the computational modeling of cognition. It has been stressed in the literature that textit{simulation}, textit{prediction}, and textit{multi-modal integration} are key aspects of cognition and that computational architectures capable of putting them into play in a biologically plausible way are a necessity.Research in this direction has brought extensive empirical evidencesuggesting that textit{Internal Models} are suitable mechanisms forsensory-motor integration. However, current Internal Models architectures show several drawbacks, mainly due to the lack of a unified substrate allowing for a true sensory-motor integration space, enabling flexible and scalable ways to model cognition under the embodiment hypothesis constraints.We propose the Self-Organized Internal ModelsArchitecture (SOIMA, a computational cognitive architecture coded by means of a network of self-organized maps, implementing coupled internal models that allow modeling multi-modal sensory-motor schemes. Our approach addresses integrally the issues of current implementations of Internal Models.We discuss the design and features of the architecture, and provide empirical results on a humanoid robot that demonstrate the benefits and potentialities of the SOIMA concept for studying cognition in artificial agents.

  20. Self-organized Criticality in an Earthquake Model on Random Network

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A simplified Olami-Feder-Christensen model on a random network has been studied. We propose a new toppling rule - when there is an unstable site toppling, the energy of the site is redistributed to its nearest neighbors randomly not averagely. The simulation results indicate that the model displays self-organized criticality when the system is conservative, and the avalanche size probability distribution of the system obeys finite size scaling. When the system is nonconservative, the model does not display scaling behavior. Simulation results of our model with different nearest neighbors q is also compared, which indicates that the spatialtopology does not alter the critical behavior of the system.

  1. Effects of Interactive Function Forms in a Self-Organized Critical Model Based on Neural Networks

    Institute of Scientific and Technical Information of China (English)

    ZHAOXiao-Wei; ZHOULi-Ming; CHENTian-Lun

    2003-01-01

    Based on the standard self-organizing map neural network model and an integrate-and-fire mechanism, we introduce a kind of coupled map lattice system to investigate scale-invariance behavior in the activity of model neural populations. We let the parameter β, which together with α represents the interactive strength between neurons, have different function forms, and we find the function forms and their parameters are very important to our model''s avalanche dynamical behaviors, especially to the emergence of different avalanche behaviors in different areas of our system.

  2. Explicit modeling of volatile organic compounds partitioning in the atmospheric aqueous phase

    Directory of Open Access Journals (Sweden)

    C. Mouchel-Vallon

    2012-09-01

    Full Text Available The gas phase oxidation of organic species is a multigenerational process involving a large number of secondary compounds. Most secondary organic species are water-soluble multifunctional oxygenated molecules. The fully explicit chemical mechanism GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere is used to describe the oxidation of organics in the gas phase and their mass transfer to the aqueous phase. The oxidation of three hydrocarbons of atmospheric interest (isoprene, octane and α-pinene is investigated for various NOx conditions. The simulated oxidative trajectories are examined in a new two dimensional space defined by the mean oxidation state and the solubility. The amount of dissolved organic matter was found to be very low (<2% under a water content typical of deliquescent aerosols. For cloud water content, 50% (isoprene oxidation to 70% (octane oxidation of the carbon atoms are found in the aqueous phase after the removal of the parent hydrocarbons for low NOx conditions. For high NOx conditions, this ratio is only 5% in the isoprene oxidation case, but remains large for α-pinene and octane oxidation cases (40% and 60%, respectively. Although the model does not yet include chemical reactions in the aqueous phase, much of this dissolved organic matter should be processed in cloud drops and modify both oxidation rates and the speciation of organic species.

  3. Multiobjective Optimization Model for Pricing and Seat Allocation Problem in Non Profit Performing Arts Organization

    DEFF Research Database (Denmark)

    Baldin, Andrea; Bille, Trine; Ellero, Andrea

    The implementation of Revenue Management (RM) techniques in non profit performing arts organizations presents new challenges compared to other sectors, such as transportion or hospitality industries, in which these techniques are more consolidated. Indeed, performing arts organizations are charac......The implementation of Revenue Management (RM) techniques in non profit performing arts organizations presents new challenges compared to other sectors, such as transportion or hospitality industries, in which these techniques are more consolidated. Indeed, performing arts organizations...... is to incentive the customers to discriminate among themselves according to their reservation price, offering a schedule of different prices corresponding to different seats in the venue. In this context, price and allocation of the theatre seating area are decision variables that allow theatre managers to manage...... of heterogeneity among customer categories in both choice and demand. The proposed model is validated with booking data referring to the Royal Danish Theatre during the period 2010-2015....

  4. Impact of Fluorescent Lighting on Oxidation of Model Wine Solutions Containing Organic Acids and Iron.

    Science.gov (United States)

    Grant-Preece, Paris; Barril, Celia; Schmidtke, Leigh M; Clark, Andrew C

    2017-03-22

    Previous studies have provided evidence that light exposure can increase oxygen consumption in wine and that the photodegradation of iron(III) tartrate could contribute to this process. In the present study, model wine solutions containing iron(III) and various organic acids, either alone or combined, were stored in sealed clear glass wine bottles and exposed to light from fluorescent lamps. Dissolved oxygen was monitored, and afterward the organic acid degradation products were determined and the capacity of the solutions to bind sulfur dioxide, the main wine preservative, was assessed. In the dark controls, little or no dissolved oxygen was consumed and the organic acids were stable. In the irradiated solutions, dissolved oxygen was consumed at a rate that was dependent on the specific organic acid present, and the latter were oxidized to various carbonyl compounds. For the solutions containing tartaric acid, malic acid, and/or citric acid, irradiation increased their sulfur dioxide-binding capacity.

  5. CONTRIBUTIONS TO THE DEVELOPMENT OF A MODEL OF ECO TECHNOLOGIC ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Dan DOBROTĂ

    2012-05-01

    Full Text Available The paper present a series of contributions to the development of a model of eco technologic organization. Managers of various organizations generally recognized the need for change, as a way to cope with competitive pressures, but many do not understand how the change should be implemented. The key to success is to integrate employees, their roles and responsibilities within the organization in a structure of processes. A process-based approach and starting with the declaration of vision and mission, analyzing critical success factors and identifying the basic processes, it is the most effective way of employment of staff in the process of change In these conditions paper addresses notions of implementation of the change in the industrial organizations: organizational change process, consequences of ignoring the change, internal and external factors of change, actions needing change

  6. Modeling organic aerosols in a megacity: potential contribution of semi-volatile and intermediate volatility primary organic compounds to secondary organic aerosol formation

    Directory of Open Access Journals (Sweden)

    A. Hodzic

    2010-06-01

    Full Text Available It has been established that observed local and regional levels of secondary organic aerosols (SOA in polluted areas cannot be explained by the oxidation and partitioning of anthropogenic and biogenic VOC precursors, at least using current mechanisms and parameterizations. In this study, the 3-D regional air quality model CHIMERE is applied to estimate the potential contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic precursors (S/IVOC in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to include explicitly the volatility distribution of primary organic aerosols (POA, their gas-particle partitioning and the gas-phase oxidation of the vapors. Two recently proposed parameterizations, those of Robinson et al. (2007 ("ROB" and Grieshop et al. (2009 ("GRI" are compared and evaluated against surface and aircraft measurements. The 3-D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS data, and for the first time also with oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (2–4 times with respect to the previously published base case without S/IVOCs (Hodzic et al., 2009, both within and downwind of the city leading to much reduced discrepancies with the total OA measurements. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The predicted production from anthropogenic and biomass burning S/IVOC represents 40–60% of the total measured SOA at the surface during the day and is somewhat larger than that from commonly measured aromatic VOCs, especially at the T1 site at the edge of the city. The SOA production from the continued multi-generation S/IVOC oxidation products continues actively

  7. Modeling the Thermodynamics of Mixed Organic-Inorganic Aerosols to Predict Water Activities and Phase Equilibria

    Science.gov (United States)

    Zuend, A.; Marcolli, C.; Luo, B.; Peter, T.

    2008-12-01

    Tropospheric aerosol particles contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behavior. While the thermodynamics of aqueous inorganic systems at atmospheric temperatures are well established, little is known about the physicochemistry of mixed organic-inorganic particles. Salting-out and salting-in effects result from organic-inorganic interactions and are used to improve industrial separation processes. In the atmosphere, they may influence the aerosol phases. Liquid-liquid phase separations into a mainly polar (aqueous) and a less polar organic phase may considerably influence the gas/particle partitioning of semi-volatile substances compared to a single phase estimation. Moreover, the phases present in the aerosol define the reaction medium for heterogeneous and multiphase chemistry occurring in aerosol particles. A correct description of these phases is needed when gas- or cloud-phase reaction schemes are adapted to aerosols. Non-ideal thermodynamic behavior in mixtures is usually described by an expression for the excess Gibbs energy. We present the group-contribution model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients), which explicitly accounts for molecular interactions between solution constituents, both organic and inorganic, to calculate activities, chemical potentials and the total Gibbs energy of mixed systems. This model allows to compute vapor-liquid (VLE), liquid-liquid (LLE) and solid-liquid (SLE) equilibria within one framework. Focusing on atmospheric applications we considered eight different cations, five anions and a wide range of alcohols/polyols as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are very well represented up to high ionic strength. We show that the semiempirical middle

  8. Isotherm-Based Thermodynamic Models for Solute Activities of Organic Acids with Consideration of Partial Dissociation.

    Science.gov (United States)

    Nandy, Lucy; Ohm, Peter B; Dutcher, Cari S

    2016-06-23

    Organic acids make up a significant fraction of the organic mass in atmospheric aerosol particles. The calculation of gas-liquid-solid equilibrium partitioning of the organic acid is therefore critical for accurate determination of atmospheric aerosol physicochemical properties and processes such as new particle formation and activation to cloud condensation nuclei. Previously, an adsorption isotherm-based statistical thermodynamic model was developed for capturing solute concentration-activity relationships for multicomponent aqueous solutions over the entire concentration range (Dutcher et al. J. Phys. Chem. C/A 2011, 2012, 2013), with model parameters for energies of adsorption successfully related to dipole-dipole electrostatic forces in solute-solvent and solvent-solvent interactions for both electrolytes and organics (Ohm et al. J. Phys. Chem. A 2015). However, careful attention is needed for weakly dissociating semivolatile organic acids. Dicarboxylic acids, such as malonic acid and glutaric acid are treated here as a mixture of nondissociated organic solute (HA) and dissociated solute (H(+) + A(-)). It was found that the apparent dissociation was greater than that predicted by known dissociation constants alone, emphasizing the effect of dissociation on osmotic and activity coefficient predictions. To avoid additional parametrization from the mixture approach, an expression was used to relate the Debye-Hückel hard-core collision diameter to the adjustable solute-solvent intermolecular distance. An improved reference state treatment for electrolyte-organic aqueous mixtures, such as that observed here with partial dissociation, has also been proposed. This work results in predictive correlations for estimation of organic acid and water activities for which there is little or no activity data.

  9. Optimum web environment model for e-marketing of religious organizations in the Republic of Croatia

    Directory of Open Access Journals (Sweden)

    Stojanka Dukić

    2013-12-01

    Full Text Available Although religious organizations are essentially conservative, they are not immune to the changes brought on by the information and communication technology. Thus, one can conclude that all religious organizations, be they more liberal or conservative in their position towards change, use information and communication technology, i.e. the communication channel that it creates, more or less successfully. In fact, a religious organization, as any other organization, can choose between a range of communication channels created by the global network system, i.e. the Internet. The web is probably the most widely used and most popular communication channel available to Internet users. However, the web is not only a communication channel; it has developed into a virtual space, which evolved from being a means of presentation into a global social network. Web environment building is often left to the professionals such as web designers and developers of web sites that focus their attention on the appearance and functionality of web sites, but do not address the mission and goals of the religious organization for which the web system has been developed. In particular, the importance of marketing approach is disregarded, i.e. the necessity to meet the needs of the faithful, who are users of religious organization ‘services’. To create a web environment for religious organizations with optimal form and content, especially in the Republic of Croatia, one must address the task using a systematic or a model approach. For this reason, a study was conducted and a model of optimal web environment for e-marketing of religious organizations in the Republic of Croatia was developed

  10. Agent based model of effects of task allocation strategies in flat organizations

    Science.gov (United States)

    Sobkowicz, Pawel

    2016-09-01

    A common practice in many organizations is to pile the work on the best performers. It is easy to implement by the management and, despite the apparent injustice, appears to be working in many situations. In our work we present a simple agent based model, constructed to simulate this practice and to analyze conditions under which the overall efficiency of the organization (for example measured by the backlog of unresolved issues) breaks down, due to the cumulative effect of the individual overloads. The model confirms that the strategy mentioned above is, indeed, rational: it leads to better global results than an alternative one, using equal workload distribution among all workers. The presented analyses focus on the behavior of the organizations close to the limit of the maximum total throughput and provide results for the growth of the unprocessed backlog in several situations, as well as suggestions related to avoiding such buildup.

  11. Modeling of organic light emitting diodes: from molecular to device properties (Conference Presentation)

    Science.gov (United States)

    Andrienko, Denis; Kordt, Pascal; May, Falk; Badinski, Alexander; Lennartz, Christian

    2016-09-01

    We will review the progress in modeling of charge transport in disordered organic semiconductors on various length-scales, from atomistic to macroscopic. This includes evaluation of charge transfer rates from first principles, parametrization of coarse-grained lattice and off-lattice models, and solving the master and drift-diffusion equations. Special attention is paid to linking the length-scales and improving the efficiency of the methods. All techniques will be illustrated on an amorphous organic semiconductor, DPBIC, a hole conductor and electron blocker used in state of the art organic light emitting diodes (OLEDs). The outlined multiscale scheme can be used to predict OLED properties without fitting parameters, starting from chemical structures of compounds.

  12. A fractal model for nuclear organization: current evidence and biological implications.

    Science.gov (United States)

    Bancaud, Aurélien; Lavelle, Christophe; Huet, Sébastien; Ellenberg, Jan

    2012-10-01

    Chromatin is a multiscale structure on which transcription, replication, recombination and repair of the genome occur. To fully understand any of these processes at the molecular level under physiological conditions, a clear picture of the polymorphic and dynamic organization of chromatin in the eukaryotic nucleus is required. Recent studies indicate that a fractal model of chromatin architecture is consistent with both the reaction-diffusion properties of chromatin interacting proteins and with structural data on chromatin interminglement. In this study, we provide a critical overview of the experimental evidence that support a fractal organization of chromatin. On this basis, we discuss the functional implications of a fractal chromatin model for biological processes and propose future experiments to probe chromatin organization further that should allow to strongly support or invalidate the fractal hypothesis.

  13. A scale-bridging modeling approach for anisotropic organic molecules at patterned semiconductor surfaces

    OpenAIRE

    Kleppmann, Nicola; Klapp, Sabine H. L.

    2014-01-01

    Hybrid systems consisting of organic molecules at inorganic semiconductor surfaces are gaining increasing importance as thin film devices for optoelectronics. The efficiency of such devices strongly depends on the collective behavior of the adsorbed molecules. In the present paper we propose a novel, coarse-grained model addressing the condensed phases of a representative hybrid system, that is, para-sexiphenyl (6P) at zinc-oxide (ZnO). Within our model, intermolecular interactions are repre-...

  14. Overcoming the organization-practice barrier in sports injury prevention: A nonhierarchical organizational model.

    Science.gov (United States)

    Dahlström, Ö; Jacobsson, J; Timpka, T

    2015-08-01

    The organization of sports at the national level has seldom been included in scientific discussions of sports injury prevention. The aim of this study was to develop a model for organization of sports that supports prevention of overuse injuries. The quality function deployment technique was applied in seminars over a two-season period to develop a national organizational structure for athletics in Sweden that facilitates prevention of overuse injuries. Three central features of the resulting model for organization of sports at the national level are (a) diminishment of the organizational hierarchy: participatory safety policy design is introduced through annual meetings where actors from different sectors of the sporting community discuss training, injury prevention, and sports safety policy; (b) introduction of a safety surveillance system: a ubiquitous system for routine collection of injury and illness data; and (c) an open forum for discussion of safety issues: maintenance of a safety forum for participants from different sectors of the sport. A nonhierarchical model for organization of sports at the national level - facilitated by modern information technology - adapted for the prevention of overuse injuries has been developed. Further research is warranted to evaluate the new organizational model in prospective effectiveness studies.

  15. Inverse modeling of the biodegradation of emerging organic contaminants in the soil-plant system

    DEFF Research Database (Denmark)

    Hurtado, Carlos; Trapp, Stefan; Bayona, Josep M.

    2016-01-01

    experimental data on the uptake of emerging organic contaminants into lettuce derived in a greenhouse experiment. Measured soil, root and leaf concentrations from four contaminants were selected within the applicability domain of a steady-state two-compartment standard plant uptake model: bisphenol A (BPA...

  16. A theoretical model to address organizational human conflict and disruptive behavior in health care organizations.

    Science.gov (United States)

    Piper, Llewellyn E

    2006-01-01

    This article proposes a theoretical model for leaders to use to address organizational human conflict and disruptive behavior in health care organizations. Leadership is needed to improve interpersonal relationships within the workforce. A workforce with a culture of internal conflict will be unable to achieve its full potential to delivery quality patient care.

  17. [Application of zebrafish model organism in the research of Chinese materia medica].

    Science.gov (United States)

    Chen, Lei; Liu, Yi; Liang, Sheng-Wang

    2012-04-01

    Zebrafish has become an important model organism in many fields of biomedical studies and been increasingly used in Chinese materia medica studies in recent years. This article summarized the achievements and prospect for zebrafish as a pharmacological and toxicological tool in the study and development of Chinese materia medica.

  18. MODELING THE MARKETING COMPONENT OF THE INNOVATIVE CAPACITY OF ORGANIZATIONS ON THE BASIS OF STATISTICAL RESEARCH

    Directory of Open Access Journals (Sweden)

    Anna A. Aletdinova

    2015-01-01

    Full Text Available The article considers the General scheme of the modeling process of marketing theinnovation pillar, is an attempt to summarize and systematize approaches tomodel building innovative capacity of organizations on the basis of the marketingconcept, the methods used to allocate.

  19. Photoelectron spectroscopy and modeling of interface properties related to organic photovoltaic cells

    NARCIS (Netherlands)

    Fahlman, Mats; Sehati, Parisa; Osikowicz, Wojciech; Braun, Slawomir; Jong, de Michel P.; Brocks, Geert

    2013-01-01

    In this short review, we will give examples on how photoelectron spectroscopy (PES) assisted by models on interface energetics can be used to study properties important to bulk heterojunction type organic photovoltaic devices focusing on the well-known bulk heterojunction blend of poly(3-hexylthioph

  20. Exploring the Structure and Task Dynamics of Terrorist Organizations Using Agent Based Modeling

    Science.gov (United States)

    2008-12-01

    policy or position of the Department of Defense or the U.S. Government. 12a. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release...Terrorist Networks, Agent Based Modeling, 2004 Madrid Attacks, Backcasting , Computational Organization Simulation 16. PRICE CODE 17. SECURITY...be understood in order to apply effective policies and practices to safeguard citizens, assets, and interests. For decades, terrorist cells have

  1. AN EMBRYONIC CHICK PANCREAS ORGAN CULTURE MODEL: CHARACTERIZATION AND NEURAL CONTROL OF EXOCRINE RELEASE

    Science.gov (United States)

    An embryonic chick (Gallus domesticus) whole-organ pancreas culture system was developed for use as an in vitro model to study cholinergic regulation of exocrine pancreatic function. The culture system was examined for characteristic exocrine function and viability by measuring e...

  2. Entropy in the Bak-Sneppen Model for Self-Organized Criticality

    Institute of Scientific and Technical Information of China (English)

    杨纯斌

    2003-01-01

    The distributions of fitness on the sites of one- and two-dimensional lattices are studied for the nearest-neighbour Bak-Sneppen model on self-organized criticality. The distributions show complicated behaviour showing that the system is far from equilibrium. By introducing the "energy" of a site, the entropy flow from the system to its environment is investigated.

  3. AN EMBRYONIC CHICK PANCREAS ORGAN CULTURE MODEL: CHARACTERIZATION AND NEURAL CONTROL OF EXOCRINE RELEASE

    Science.gov (United States)

    An embryonic chick (Gallus domesticus) whole-organ pancreas culture system was developed for use as an in vitro model to study cholinergic regulation of exocrine pancreatic function. The culture system was examined for characteristic exocrine function and viability by measuring e...

  4. Bacteria, Yeast, Worms, and Flies: Exploiting Simple Model Organisms to Investigate Human Mitochondrial Diseases

    Science.gov (United States)

    Rea, Shane L.; Graham, Brett H.; Nakamaru-Ogiso, Eiko; Kar, Adwitiya; Falk, Marni J.

    2010-01-01

    The extensive conservation of mitochondrial structure, composition, and function across evolution offers a unique opportunity to expand our understanding of human mitochondrial biology and disease. By investigating the biology of much simpler model organisms, it is often possible to answer questions that are unreachable at the clinical level.…

  5. Draft Genome Sequence of the Model Naphthalene-Utilizing Organism Pseudomonas putida OUS82

    DEFF Research Database (Denmark)

    Tay, Martin; Roizman, Dan; Cohen, Yehuda

    2014-01-01

    Pseudomonas putida OUS82 was isolated from petrol- and oil-contaminated soil in 1992, and ever since, it has been used as a model organism to study the microbial assimilation of naphthalene and phenanthrene. Here, we report the 6.7-Mb draft genome sequence of P. putida OUS82 and analyze its featu...

  6. Youth Purpose through the Lens of the Theory of Organizing Models of Thinking

    Science.gov (United States)

    Arantes, Valeria; Araujo, Ulisses; Pinheiro, Viviane; Moreno Marimon, Montserrat; Sastre, Genoveva

    2017-01-01

    Purpose represents a unique opportunity for identifying and analyzing the complexity of human reasoning, considering that its constitution brings together cognitive, affective and social elements. In this article, we use the Theory of Organizing Models of Thinking (OMT), an epistemological and methodological approach based on developmental…

  7. Investigating inbreeding depression for heat stress tolerance in the model organism Drosophila melanogaster

    DEFF Research Database (Denmark)

    Pedersen, Kamilla Sofie; Pedersen, Louise Dybdahl; Sørensen, Anders Christian

    2012-01-01

    -year university students and discuss learning outcomes of the exercise as an example of inquiry-based science teaching. We use the model organism Drosophila melanogaster to test the ability of inbred and control (non-inbred) females to survive heat stress exposure. Flies were anaesthetised and collected...

  8. Bacteria, Yeast, Worms, and Flies: Exploiting Simple Model Organisms to Investigate Human Mitochondrial Diseases

    Science.gov (United States)

    Rea, Shane L.; Graham, Brett H.; Nakamaru-Ogiso, Eiko; Kar, Adwitiya; Falk, Marni J.

    2010-01-01

    The extensive conservation of mitochondrial structure, composition, and function across evolution offers a unique opportunity to expand our understanding of human mitochondrial biology and disease. By investigating the biology of much simpler model organisms, it is often possible to answer questions that are unreachable at the clinical level.…

  9. Animal model of non-bacterial multiple organ dysfunction syndrome in the elderly

    Institute of Scientific and Technical Information of China (English)

    Qinglei ZHU; Shiwen WANG; Jie YANG; Tong YIN; Xiaoshun QIAN; Qiao XUE; Bin XU

    2004-01-01

    Objective To establish a model of multiple organ dysfunction syndrome in the elderly (MODSE) by intraperitoneal injection of different doses of zymosan, and to compare the multiple organ dysfunction syndrome (MODS) in adult and in the elderly rats. Methods Adult and senile rats, injected with different doses of zymosan intraperitoneally were examined for the changes in the function and morphology of the vital organs, including heart, liver, brain, lungs, and kidneys using blood gas and biochemistry analysis and histopathological examination methods. Results Compared with the normal controls of the adult and the elderly rats, the blood gas and blood biochemistry changed in different degrees in the different dosed zymosan groups. Pathological changes were also found in the vital organs including lungs, heart, liver, brain, kidneys, erc in the experimental groups. Under the same concentrations of zymosan, the reductions in respiratory, cardiac and renal functions in the senile groups were much more severe than those in the corresponding adult group. In the similar degree of model duplication, the senile rats had the tendency to die later than the adult rats. Conclusions Zymosan can be used in both elderly and adult rats to induce MODS model, and the best dosage for MODSE was 0.Sg/kg injected peritoneally. The model would hopefully be used in the study of mechanisms and the therapeutics on MODSE.

  10. Emergence of the chicken as a model organism: implications for agriculture and biology.

    Science.gov (United States)

    Burt, D W

    2007-07-01

    Many of the features of the chicken make it an ideal model organism for phylogenetics and embryology, along with applications in agriculture and medicine. The availability of new tools such as whole genome gene expression arrays and single nucleotide polymorphism panels, coupled with the genome sequence, will enhance this position. These advances are reviewed and their implications are discussed.

  11. Faculty Organization Policy System as an Illustration of Easton's "Dynamic Response Model of a Political System."

    Science.gov (United States)

    Ebersole, Jay F.

    This paper is an exercise in the study of David Easton's "dynamic response model of a political system," as found in "A Systems Analysis of Political Life." After a brief review of the theory, the development of a local "Reduction in Force" policy is described as an example of faculty organization policy influence on…

  12. Coupling Molecular Modeling to the Traditional "IR-ID" Exercise in the Introductory Organic Chemistry Laboratory

    Science.gov (United States)

    Stokes-Huby, Heather; Vitale, Dale E.

    2007-01-01

    This exercise integrates the infrared unknown identification ("IR-ID") experiment common to most organic laboratory syllabi with computer molecular modeling. In this modification students are still required to identify unknown compounds from their IR spectra, but must additionally match some of the absorptions with computed frequencies they…

  13. A Model of Sustainability for Professional Organizations: Using a Learning Management System to Offer Continuing Education

    Science.gov (United States)

    Sparrow, Gregory S.

    2017-01-01

    Professional membership organizations have long maintained their exposure and revenue stream through a variety of traditional avenues, most notably memberships, sponsored conferences, and professional journals. The synergy of this three-tiered model has depended on a certain enhanced status derived from membership benefits and proprietary…

  14. A Model of Institutional Creative Change for Assessing Universities as Learning Organizations

    Science.gov (United States)

    Sternberg, Robert J.

    2015-01-01

    Universities, like students, differ in their ability to learn and to recreate themselves. In this article, I present a 3-part model of institutional creative change for assessing universities as learning organizations that can move creatively into the future. The first part, prerequisites, deals with actual ability to change creatively and belief…

  15. What Happens when Representations Fail to Represent? Graduate Students' Mental Models of Organic Chemistry Diagrams

    Science.gov (United States)

    Strickland, Amanda M.; Kraft, Adam; Bhattacharyya, Gautam

    2010-01-01

    As part of our investigations into the development of representational competence, we report results from a study in which we elicited sixteen graduate students' expressed mental models of commonly-used terms for describing organic reactions--functional group, nucleophile/electrophile, acid/base--and for diagrams of transformations and their…

  16. Modelling the light absorption properties of particulate matter forming organic particles suspended in seawater. Part 2. Modelling results

    Directory of Open Access Journals (Sweden)

    Bogdan Woźniak

    2005-12-01

    Full Text Available Model spectra of mass-specific absorption coefficients a*OM(λ were established for 26 naturally occurring organic substances or their possible mixtures, capable of forming particulate organic matter (POM in the sea. An algorithm was constructed, and the set of spectra of a*OM(λ was used to determine the spectra of the imaginary part of the complex refractive index n'p(λ characteristic of different physical types and chemical classes of POM commonly occurring in sea water. The variability in the spectra and absolute values of n'p for the various model classes and types of POM was shown to range over many orders of magnitude. This implies that modelling the optical properties of sea water requires a multi-component approach that takes account of the numerous living and non-living fractions of POM, each of which has a different value of n'p.

  17. A mass transfer model for predicting emission of the volatile organic compounds in wet building materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tao; JIA Li

    2008-01-01

    A new mass transfer model is developped to predict the volatile organic compounds (VOCs) from fresh wet building materials. The dry section of wet materials during the process of VOC emission from wet building materials is considered in this new model, differing from the mass transfer-based models in other literatures. The mechanism of effect of saturated vapor pressure on the surface of wet building materials in the process of VOC emission is discussed. The concentration of total volatile organic compounds (TVOC) in the building materials gradually decreases as the emission of VOCs begins, and the vapor pressure of VOCs on the surface of wet building materials decreases in the case of newly wet building materials. To ensure the partial pressure of VOCs on the surface of wet building materials to be saturated vapor pressure, the interface of gas-wet layer is lowered, and a dry layer of no-volatile gases in the material is formed. Compared with the results obtained by VB model, CFD model and the ex-periment data, the results obtained by the present model agree well with the results obtained by CFD model and the experiment data. The present model is more accurate in predicting emission of VOC from wet building materials than VB model.

  18. Organ explant culture of neonatal rat ventricles: a new model to study gene and cell therapy.

    Directory of Open Access Journals (Sweden)

    A Dénise den Haan

    Full Text Available Testing cardiac gene and cell therapies in vitro requires a tissue substrate that survives for several days in culture while maintaining its physiological properties. The purpose of this study was to test whether culture of intact cardiac tissue of neonatal rat ventricles (organ explant culture may be used as a model to study gene and cell therapy. We compared (immuno histology and electrophysiology of organ explant cultures to both freshly isolated neonatal rat ventricular tissue and monolayers. (Immuno histologic studies showed that organ explant cultures retained their fiber orientation, and that expression patterns of α-actinin, connexin-43, and α-smooth muscle actin did not change during culture. Intracellular voltage recordings showed that spontaneous beating was rare in organ explant cultures (20% and freshly isolated tissue (17%, but common (82% in monolayers. Accordingly, resting membrane potential was -83.9±4.4 mV in organ explant cultures, -80.5±3.5 mV in freshly isolated tissue, and -60.9±4.3 mV in monolayers. Conduction velocity, measured by optical mapping, was 18.2±1.0 cm/s in organ explant cultures, 18.0±1.2 cm/s in freshly isolated tissue, and 24.3±0.7 cm/s in monolayers. We found no differences in action potential duration (APD between organ explant cultures and freshly isolated tissue, while APD of monolayers was prolonged (APD at 70% repolarization 88.8±7.8, 79.1±2.9, and 134.0±4.5 ms, respectively. Organ explant cultures and freshly isolated tissue could be paced up to frequencies within the normal range for neonatal rat (CL 150 ms, while monolayers could not. Successful lentiviral (LV transduction was shown via Egfp gene transfer. Co-culture of organ explant cultures with spontaneously beating cardiomyocytes increased the occurrence of spontaneous beating activity of organ explant cultures to 86%. We conclude that organ explant cultures of neonatal rat ventricle are structurally and electrophysiologically similar

  19. Role of the lung in the progression of multiple organ dysfunction syndrome in ageing rat model

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-ping; ZHU Qing-lei; XUE Qiao; LI Yang; QIAN Xiao-shun; WANG Zhong-liang; WANG Shi-wen

    2012-01-01

    Background Multiple organ dysfunction syndrome in the elderly (MODSE) is a problem with high mortality in the critical care of elderly patients.The pathogenesis of MODSE remains elusive.This study aimed to establish rat models of MODSE and to investigate the pathogenetic mechanism responsible for the development of MODSE in the rat models.Methods Twenty-four-month old rats (elderly) received intravenous injection of lipopolysaccharide (LPS) to induce rat model of MODSE.In the model,we observed the physical responses,biochemical indices changes,histopathological features of vital organs,including lung,liver,heart,and kidney.We also investigated the sequence of individual organ dysfunction and changes of proinflammatory factors.Three-month-old rats.serving as young rat controls,received parallel procedures.Besides,normal saline injection was also performed on elderly and young control rats.Results All rats displayed different degree of physical response after LPS injection,preceded by deterioration of respiratory status.At 6 hours,lung injury was observed,which started eariier than other organ injury that was observed in about 24 hours.Furthermore,all vital organ injury was more severe in elderiy rats than in young rats at the same time points.After LPS injection,pulmonary alveolar macrophages apoptosis rate increased obviously,and was more significant in elderly rats ((43.4±8.4)%) than in young rats ((24.2±3.0)%).LPS injection also enhanced tumor necrosis factor α (TNF-α) concentration significantly in these organs.Its peak concentration appeared at 6 hours in lung tissue and at 24 hours in other organs after LPS injection.TNF-α level was higher in elderly rats than in young rats at the same time points.The increase was most significant in lung tissue.After intravenous administration of LPS.toll-like receptor 4(TLR4) expression in lung tissue was upregulated markedly,and peaked at 6 hours.In contrast,upregulation of TLR4expression in liver peaked at 24

  20. Modeling SOAaq Formation: Explicit Organic Chemistry in Cloud Droplets with CMAQ

    Science.gov (United States)

    Carlton, A. G.; Sareen, N.; Fahey, K.; Hutzell, W. T.

    2013-12-01

    Aqueous multiphase chemistry in the atmosphere has a substantial impact on climate and can lead to air quality changes that adversely impact human health and the environment. The chemistry is complex because of the variety of compounds present in the atmosphere and the phase transitions associated with multiphase reactions. These reactions can lead to the formation of secondary organic aerosols (SOAAQ) in the atmosphere. When included, current photochemical models typically use a simple parameterization to describe SOAAQ formation. Here, we discuss the implementation of explicit aqueous SOA chemistry in a box model of the CMAQ 5.0.1 aqueous phase chemistry mechanism using the Kinetic PreProcessor (KPP). The expanded chemistry model includes reactions of glyoxal, methylglyoxal, and glycolaldehyde as precursors to form SOAAQ and is based on the mechanism from Lim et. al. 2010. The current aqueous phase chemistry module in CMAQ uses a forward Euler method to solve the system of oxidation equations, estimating the pH with a bisection method assuming electroneutrality, and multiphase processes are solved sequentially. This is not robust for systems with large dynamic range (e.g., multiphase systems), and inhibits expansion of the aqueous phase chemical mechanism to adequately incorporate the growing body of literature that describes multiphase organic chemistry. The KPP solver allows for all processes to be solved simultaneously and facilitates expansion of the current mechanism. Addition of explicit organic reactions and H2O2 photolysis in the KPP box model results in increased mass of organic aerosol and more realistic predictions. For particulate matter focused air quality management strategies to be effective, it is important that models move away from the yield-based approach currently used and expand to include more explicit organic chemistry.

  1. Lessons from model organisms: phenotypic robustness and missing heritability in complex disease.

    Directory of Open Access Journals (Sweden)

    Christine Queitsch

    Full Text Available Genetically tractable model organisms from phages to mice have taught us invaluable lessons about fundamental biological processes and disease-causing mutations. Owing to technological and computational advances, human biology and the causes of human diseases have become accessible as never before. Progress in identifying genetic determinants for human diseases has been most remarkable for Mendelian traits. In contrast, identifying genetic determinants for complex diseases such as diabetes, cancer, and cardiovascular and neurological diseases has remained challenging, despite the fact that these diseases cluster in families. Hundreds of variants associated with complex diseases have been found in genome-wide association studies (GWAS, yet most of these variants explain only a modest amount of the observed heritability, a phenomenon known as "missing heritability." The missing heritability has been attributed to many factors, mainly inadequacies in genotyping and phenotyping. We argue that lessons learned about complex traits in model organisms offer an alternative explanation for missing heritability in humans. In diverse model organisms, phenotypic robustness differs among individuals, and those with decreased robustness show increased penetrance of mutations and express previously cryptic genetic variation. We propose that phenotypic robustness also differs among humans and that individuals with lower robustness will be more responsive to genetic and environmental perturbations and hence susceptible to disease. Phenotypic robustness is a quantitative trait that can be accurately measured in model organisms, but not as yet in humans. We propose feasible approaches to measure robustness in large human populations, proof-of-principle experiments for robustness markers in model organisms, and a new GWAS design that takes differences in robustness into account.

  2. A 3-D mathematical model to identify organ-specific risks in rats during thermal stress.

    Science.gov (United States)

    Rakesh, Vineet; Stallings, Jonathan D; Helwig, Bryan G; Leon, Lisa R; Jackson, David A; Reifman, Jaques

    2013-12-01

    Early prediction of the adverse outcomes associated with heat stress is critical for effective management and mitigation of injury, which may sometimes lead to extreme undesirable clinical conditions, such as multiorgan dysfunction syndrome and death. Here, we developed a computational model to predict the spatiotemporal temperature distribution in a rat exposed to heat stress in an attempt to understand the correlation between heat load and differential organ dysfunction. The model includes a three-dimensional representation of the rat anatomy obtained from medical imaging and incorporates the key mechanisms of heat transfer during thermoregulation. We formulated a novel approach to estimate blood temperature by accounting for blood mixing from the different organs and to estimate the effects of the circadian rhythm in body temperature by considering day-night variations in metabolic heat generation and blood perfusion. We validated the model using in vivo core temperature measurements in control and heat-stressed rats and other published experimental data. The model predictions were within 1 SD of the measured data. The liver demonstrated the greatest susceptibility to heat stress, with the maximum temperature reaching 2°C higher than the measured core temperature and 95% of its volume exceeding the targeted experimental core temperature. Other organs also attained temperatures greater than the core temperature, illustrating the need to monitor multiple organs during heat stress. The model facilitates the identification of organ-specific risks during heat stress and has the potential to aid in the development of improved clinical strategies for thermal-injury prevention and management.

  3. Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations

    Science.gov (United States)

    Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

    1996-08-01

    An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road dust, tire wear, brake lining dust, meat cooking operations, industrial oil-fired boilers, roofing tar pots, natural gas combustion in residential homes, cigarette smoke, fireplaces burning oak and pine wood, and plant leaf abrasion products. These primary fine particle source emissions were supplied to a computer-based model that simulates atmospheric transport, dispersion, and dry deposition based on the time series of hourly wind observations and mixing depths. Monthly average fine particle organic compound concentrations that would prevail if the primary organic aerosol were transported without chemical reaction were computed for more than 100 organic compounds within an 80 km × 80 km modeling area centered over Los Angeles. The monthly average compound concentrations predicted by the transport model were compared to atmospheric measurements made at monitoring sites within the study area during 1982. The predicted seasonal variation and absolute values of the concentrations of the more stable compounds are found to be in reasonable agreement with the ambient observations. While model predictions for the higher molecular weight polycyclic aromatic hydrocarbons (PAH) are in agreement with ambient observations, lower molecular weight PAH show much higher predicted than measured atmospheric concentrations in the particle phase, indicating atmospheric decay by chemical reactions or evaporation from the particle phase. The atmospheric concentrations of dicarboxylic acids and aromatic polycarboxylic acids greatly exceed the contributions that

  4. Modeling the elution of organic chemicals from a melting homogeneous snow pack.

    Science.gov (United States)

    Meyer, Torsten; Wania, Frank

    2011-06-01

    Organic chemicals are often released in peak concentrations from melting snow packs. A simple, mechanistic snowmelt model was developed to simulate and predict the elution of organic substances from melting, homogeneous snow, as influenced by chemical properties and snow pack characteristics. The model calculates stepwise the chemical transport along with the melt water flow in a multi-layered snow pack, based on chemical equilibrium partitioning between the individual bulk snow phases. The model succeeds in reproducing the elution behavior of several organic contaminants observed in previously conducted cold room experiments. The model aided in identifying four different types of enrichment of organic substances during snowmelt. Water soluble substances experience peak releases early during a melt period (type 1), whereas chemicals that strongly sorb to particulate matter (PM) or snow grain surfaces elute at the end of melting (type 2). Substances that are somewhat water soluble and at the same time have a high affinity for snow grain surfaces may exhibit increasing concentrations in the melt water (type 3). Finally, elution sequences involving peak loads both at the beginning and the end of melting are simulated for chemicals that are partially dissolved in the aqueous melt water phase and partially sorbed to PM (type 4). The extent of type 1 enrichment mainly depends on the snow depth, whereby deeper snow generates more pronounced concentration peaks. PM influences the elution behavior of organic chemicals strongly because of the very large natural variability in the type and amount of particles present in snow. Urban and road-side snow rich in PM can generate type 2 concentration peaks at the end of the melt period for even relatively water soluble substances. From a clean, melting snow pack typical for remote regions, even fairly hydrophobic chemicals can be released in type 1 mode while being almost completely dissolved in the aqueous melt water phase. The

  5. Modelling day-time concentrations of biogenic volatile organic compounds in a boreal forest canopy

    Directory of Open Access Journals (Sweden)

    H. K. Lappalainen

    2010-08-01

    Full Text Available Three different models for day-time atmospheric methanol, acetaldehyde, acetone, isoprene and monoterpene concentrations were developed using measurements above a boreal forest stand in Southern Finland in 2006–2007 and tested against an independent dataset from the same forest measured in summer 2008. The models were based on the exponential relationship between air temperature and the concentration of biogenic volatile organic compounds (BVOC. Our first model for BVOC concentrations was a simple exponential function of air temperature (T-model. The T-model could explain 27–66% of the variation of all the compounds, but it failed to catch the extremely high concentration peaks observed in summer. To improve the temperature model we developed two other models. The second model, a Temperature-State of Development- model (T-S model, included two explaining variables: air temperature and the seasonal photosynthetic efficiency. This model performed slightly better compared to the T-model for both datasets and increased the fraction of variation explained to 29–69%, but it still could not explain the high concentration peaks. To explain those we modified the T-S model to include environmental triggers that could increase the concentrations momentarily. The triggers that improved the model most were high photosynthetically active photon flux density (PPDF compared to the seasonally available radiation and high ozone concentration. The Trigger model described the peak concentrations somewhat better than T or T-S model, thus the level of explanation was improved and was 30–71%. This study shows the importance to include seasonal variations in photosynthetic efficiency when modeling BVOC concentrations and presents the idea of a trigger model for explaining high peak concentrations of BVOCs. Our study suggests that when developing a trigger type modelfurther the model and the triggers should be more compounds-specific.

  6. Organic complexation of rare earth elements in natural waters: Evaluating model calculations from ultrafiltration data

    Science.gov (United States)

    Pourret, Olivier; Davranche, Mélanie; Gruau, Gérard; Dia, Aline

    2007-06-01

    The Stockholm Humic Model (SHM) and Humic Ion-Binding Models V and VI were compared for their ability to predict the role of dissolved organic matter (DOM) in the speciation of rare earth elements (REE) in natural waters. Unlike Models V and VI, SHM is part of a speciation code that also allows us to consider dissolution/precipitation, sorption/desorption and oxidation/reduction reactions. In this context, it is particularly interesting to test the performance of SHM. The REE specific equilibrium constants required by the speciation models were estimated using linear free-energy relationships (LFER) between the first hydrolysis constants and the stability constants for REE complexation with lactic and acetic acid. Three datasets were used for the purpose of comparison: (i) World Average River Water (Dissolved Organic Carbon (DOC) = 5 mg L -1), previously investigated using Model V, was reinvestigated using SHM and Model VI; (ii) two natural organic-rich waters (DOC = 18-24 mg L -1), whose REE speciation has already been determined with both Model V and ultrafiltration studies, were also reinvestigated using SHM and Model VI; finally, (iii) new ultrafiltration experiments were carried out on samples of circumneutral-pH (pH 6.2-7.1), organic-rich (DOC = 7-20 mg L -1) groundwaters from the Kervidy-Naizin and Petit-Hermitage catchments, western France. The results were then compared with speciation predictions provided by Model VI and SHM, successively. When applied to World Average River Water, both Model VI and SHM yield comparable results, confirming the earlier finding that a large fraction of the dissolved REE in rivers occurs as organic complexes This implies that the two models are equally valid for calculating REE speciation in low-DOC waters at circumneutral-pH. The two models also successfully reproduced ultrafiltration results obtained for DOC-rich acidic groundwaters and river waters. By contrast, the two models yielded different results when compared to

  7. A fugacity based multimedia environmental fate model of organic contaminants in Massachusetts Bay

    Energy Technology Data Exchange (ETDEWEB)

    Keys, D.; Shea, D. [North Carolina State Univ., Raleigh, NC (United States)

    1995-12-31

    A new sewage outfall is being constructed in Massachusetts Bay as part of the pollution abatement program in Boston Harbor. Previous models of potential environmental impact from the new sewage outfall in Massachusetts Bay have either relied upon hydrodynamic transport models that assume conservative behavior of the contaminants or on non-quantitative conceptual models of non-conservative behavior. The authors have found that a more quantitative mass balance model is necessary to better predict contaminant exposure resulting from effluent discharge through the new outfall. Hence, the authors have developed a time-variant, multimedia environmental model of organic contaminants in the air, water, and sediment phases of Massachusetts Bay. This model is based on the fugacity approach developed by Donald Mackay and is a level 4 unsteady-state model that includes flows through the system. Advection, reaction, and intermedia transport processes are incorporated into the model as first order rate processes and parameters for the model include environmental parameters, physical-chemical properties, contaminant loading estimates from major sources, and transport parameters. The model was applied to several organic contaminants found in Massachusetts Bay water and sediment: naphthalene, benzo(a)pyrene, fluoranthene, dieldrin, 4,4{prime}-DDT, and the polychlorinated biphenyl C16(153). Model output includes a steady-state bay-wide average of water and sediment concentrations, relative distribution of mass after one month at steady state, time to reach steady-state, and residence times. The calculated steady-state concentrations were compared to recent observed values. In addition, sensitivity analysis of the model was performed to indicate which model parameters are most sensitive to perturbation.

  8. Testing the Utility of a Modified Organ Donation Model among African American Adults

    Science.gov (United States)

    Robinson, Dana H. Z.; Perryman, Jennie P.; Thompson, Nancy J.; Amaral, Sandra; Jacob Arriola, Kimberly R.

    2011-01-01

    African Americans are overrepresented on the organ transplant waiting list because they are disproportionately impacted by certain health conditions that potentially warrant a life-saving transplant. While the African American need for transplantation is considerably high, organ and tissue donation rates are comparatively low, resulting in African Americans spending more than twice the amount of time on the national transplant waiting list as compared to people of other racial/ethnic backgrounds. There are a multitude of factors that contribute to the reluctance expressed by African Americans with respect to organ donation. This study proposes the use of an adaptation of the Organ Donation Model to explore the ways in which knowledge, trust in the donation/allocation process, and religious beliefs impact African American donation decision making. Bivariate and path analyses demonstrated that alignment with religious beliefs was the greatest driving factor with respect to attitudes towards donation; attitudes were significantly associated with donation intentions; and knowledge is directly associated with intentions to serve as a potential deceased organ donor. The significance of these variables speaks to the importance of their inclusion in a model that focuses on the African American population and offers new direction for more effective donation education efforts. PMID:21698439

  9. A computationally-efficient secondary organic aerosol module for three-dimensional air quality models

    Science.gov (United States)

    Liu, P.; Zhang, Y.

    2008-07-01

    Accurately simulating secondary organic aerosols (SOA) in three-dimensional (3-D) air quality models is challenging due to the complexity of the physics and chemistry involved and the high computational demand required. A computationally-efficient yet accurate SOA module is necessary in 3-D applications for long-term simulations and real-time air quality forecasting. A coupled gas and aerosol box model (i.e., 0-D CMAQ-MADRID 2) is used to optimize relevant processes in order to develop such a SOA module. Solving the partitioning equations for condensable volatile organic compounds (VOCs) and calculating their activity coefficients in the multicomponent mixtures are identified to be the most computationally-expensive processes. The two processes can be speeded up by relaxing the error tolerance levels and reducing the maximum number of iterations of the numerical solver for the partitioning equations for organic species; conditionally activating organic-inorganic interactions; and parameterizing the calculation of activity coefficients for organic mixtures in the hydrophilic module. The optimal speed-up method can reduce the total CPU cost by up to a factor of 31.4 from benchmark under the rural conditions with 2 ppb isoprene and by factors of 10 71 under various test conditions with 2 10 ppb isoprene and >40% relative humidity while maintaining ±15% deviation. These speed-up methods are applicable to other SOA modules that are based on partitioning theories.

  10. Improved AIOMFAC model parameterisation of the temperature dependence of activity coefficients for aqueous organic mixtures

    Science.gov (United States)

    Ganbavale, G.; Zuend, A.; Marcolli, C.; Peter, T.

    2015-01-01

    This study presents a new, improved parameterisation of the temperature dependence of activity coefficients in the AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) model applicable for aqueous as well as water-free organic solutions. For electrolyte-free organic and organic-water mixtures the AIOMFAC model uses a group-contribution approach based on UNIFAC (UNIversal quasi-chemical Functional-group Activity Coefficients). This group-contribution approach explicitly accounts for interactions among organic functional groups and between organic functional groups and water. The previous AIOMFAC version uses a simple parameterisation of the temperature dependence of activity coefficients, aimed to be applicable in the temperature range from ~ 275 to ~ 400 K. With the goal to improve the description of a wide variety of organic compounds found in atmospheric aerosols, we extend the AIOMFAC parameterisation for the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon to atmospherically relevant low temperatures. To this end we introduce a new parameterisation for the temperature dependence. The improved temperature dependence parameterisation is derived from classical thermodynamic theory by describing effects from changes in molar enthalpy and heat capacity of a multi-component system. Thermodynamic equilibrium data of aqueous organic and water-free organic mixtures from the literature are carefully assessed and complemented with new measurements to establish a comprehensive database, covering a wide temperature range (~ 190 to ~ 440 K) for many of the functional group combinations considered. Different experimental data types and their processing for the estimation of AIOMFAC model parameters are discussed. The new AIOMFAC parameterisation for the temperature dependence of activity coefficients from low to high temperatures shows an overall improvement of 28% in

  11. Regional modelling of nitrate leaching from Swiss organic and conventional cropping systems under climate change

    Science.gov (United States)

    Calitri, Francesca; Necpalova, Magdalena; Lee, Juhwan; Zaccone, Claudio; Spiess, Ernst; Herrera, Juan; Six, Johan

    2016-04-01

    Organic cropping systems have been promoted as a sustainable alternative to minimize the environmental impacts of conventional practices. Relatively little is known about the potential to reduce NO3-N leaching through the large-scale adoption of organic practices. Moreover, the potential to mitigate NO3-N leaching and thus the N pollution under future climate change through organic farming remain unknown and highly uncertain. Here, we compared regional NO3-N leaching from organic and conventional cropping systems in Switzerland using a terrestrial biogeochemical process-based model DayCent. The objectives of this study are 1) to calibrate and evaluate the model for NO3-N leaching measured under various management practices from three experiments at two sites in Switzerland; 2) to estimate regional NO3-N leaching patterns and their spatial uncertainty in conventional and organic cropping systems (with and without cover crops) for future climate change scenario A1B; 3) to explore the sensitivity of NO3-N leaching to changes in soil and climate variables; and 4) to assess the nitrogen use efficiency for conventional and organic cropping systems with and without cover crops under climate change. The data for model calibration/evaluation were derived from field experiments conducted in Liebefeld (canton Bern) and Eschikon (canton Zürich). These experiments evaluated effects of various cover crops and N fertilizer inputs on NO3-N leaching. The preliminary results suggest that the model was able to explain 50 to 83% of the inter-annual variability in the measured soil drainage (RMSE from 12.32 to 16.89 cm y-1). The annual NO3-N leaching was also simulated satisfactory (RMSE = 3.94 to 6.38 g N m-2 y-1), although the model had difficulty to reproduce the inter-annual variability in the NO3-N leaching losses correctly (R2 = 0.11 to 0.35). Future climate datasets (2010-2099) from the 10 regional climate models (RCM) were used in the simulations. Regional NO3-N leaching

  12. Spatiotemporal modeling of soil organic carbon stocks across a subtropical region.

    Science.gov (United States)

    Ross, Christopher Wade; Grunwald, Sabine; Myers, David Brenton

    2013-09-01

    Given the significance and complex nature of soil organic carbon in the context of the global carbon cycle, the need exists for more accurate and economically feasible means of soil organic carbon analysis and its underlying spatial variation at regional scale. The overarching goal of this study was to assess both the spatial and temporal variability of soil organic carbon within a subtropical region of Florida, USA. Specifically, the objectives were to: i) quantify regional soil organic carbon stocks for historical and current conditions and ii) determine whether the soils have acted as a net sink or a net source for atmospheric carbon-dioxide over an approximate 40 year time period. To achieve these objectives, geostatistical interpolation models were used in conjunction with "historical" and "current" datasets to predict soil organic carbon stocks for the upper 20 cm soil profile of the study area. Soil organic carbon estimates derived from the models ranged from 102 to 108 Tg for historical conditions and 211 to 320 Tg for current conditions, indicating that soils in the study area have acted as a net sink for atmospheric carbon over the last 40 years. A paired resampling of historical sites supported the geostatistical estimates, and resulted in an average increase of 0.8 g carbon m(-2) yr(-1) across all collocated samples. Accurately assessing the spatial and temporal state of soil organic carbon at regional scale is critical to further our understanding of global carbon stocks and provide a baseline so that the effects sustainable land use policy can be evaluated.

  13. Modeling the influence of alkane molecular structure on secondary organic aerosol formation.

    Science.gov (United States)

    Aumont, Bernard; Camredon, Marie; Mouchel-Vallon, Camille; La, Stéphanie; Ouzebidour, Farida; Valorso, Richard; Lee-Taylor, Julia; Madronich, Sasha

    2013-01-01

    Secondary Organic Aerosols (SOA) production and ageing is a multigenerational oxidation process involving the formation of successive organic compounds with higher oxidation degree and lower vapor pressure. Intermediate Volatility Organic Compounds (IVOC) emitted to the atmosphere are expected to be a substantial source of SOA. These emitted IVOC constitute a complex mixture including linear, branched and cyclic alkanes. The explicit gas-phase oxidation mechanisms are here generated for various linear and branched C10-C22 alkanes using the GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) and SOA formation is investigated for various homologous series. Simulation results show that both the size and the branching of the carbon skeleton are dominant factors driving the SOA yield. However, branching appears to be of secondary importance for the particle oxidation state and composition. The effect of alkane molecular structure on SOA yields appears to be consistent with recent laboratory observations. The simulated SOA composition shows, however, an unexpected major contribution from multifunctional organic nitrates. Most SOA contributors simulated for the oxidation of the various homologous series are far too reduced to be categorized as highly oxygenated organic aerosols (OOA). On a carbon basis, the OOA yields never exceeded 10% regardless of carbon chain length, molecular structure or ageing time. This version of the model appears clearly unable to explain a large production of OOA from alkane precursors.

  14. Mammal-Like Organization of the Avian Midbrain Central Gray and a Reappraisal of the Intercollicular Nucleus

    Science.gov (United States)

    Kingsbury, Marcy A.; Kelly, Aubrey M.; Schrock, Sara E.; Goodson, James L.

    2011-01-01

    In mammals, rostrocaudal columns of the midbrain periaqueductal gray (PAG) regulate diverse behavioral and physiological functions, including sexual and fight-or-flight behavior, but homologous columns have not been identified in non-mammalian species. In contrast to mammals, in which the PAG lies ventral to the superior colliculus and surrounds the cerebral aqueduct, birds exhibit a hypertrophied tectum that is displaced laterally, and thus the midbrain central gray (CG) extends mediolaterally rather than dorsoventrally as in mammals. We therefore hypothesized that the avian CG is organized much like a folded open PAG. To address this hypothesis, we conducted immunohistochemical comparisons of the midbrains of mice and finches, as well as Fos studies of aggressive dominance, subordinance, non-social defense and sexual behavior in territorial and gregarious finch species. We obtained excellent support for our predictions based on the folded open model of the PAG and further showed that birds possess functional and anatomical zones that form longitudinal columns similar to those in mammals. However, distinguishing characteristics of the dorsal/dorsolateral PAG, such as a dense peptidergic innervation, a longitudinal column of neuronal nitric oxide synthase neurons, and aggression-induced Fos responses, do not lie within the classical avian CG, but in the laterally adjacent intercollicular nucleus (ICo), suggesting that much of the ICo is homologous to the dorsal PAG. PMID:21694758

  15. Mammal-like organization of the avian midbrain central gray and a reappraisal of the intercollicular nucleus.

    Directory of Open Access Journals (Sweden)

    Marcy A Kingsbury

    Full Text Available In mammals, rostrocaudal columns of the midbrain periaqueductal gray (PAG regulate diverse behavioral and physiological functions, including sexual and fight-or-flight behavior, but homologous columns have not been identified in non-mammalian species. In contrast to mammals, in which the PAG lies ventral to the superior colliculus and surrounds the cerebral aqueduct, birds exhibit a hypertrophied tectum that is displaced laterally, and thus the midbrain central gray (CG extends mediolaterally rather than dorsoventrally as in mammals. We therefore hypothesized that the avian CG is organized much like a folded open PAG. To address this hypothesis, we conducted immunohistochemical comparisons of the midbrains of mice and finches, as well as Fos studies of aggressive dominance, subordinance, non-social defense and sexual behavior in territorial and gregarious finch species. We obtained excellent support for our predictions based on the folded open model of the PAG and further showed that birds possess functional and anatomical zones that form longitudinal columns similar to those in mammals. However, distinguishing characteristics of the dorsal/dorsolateral PAG, such as a dense peptidergic innervation, a longitudinal column of neuronal nitric oxide synthase neurons, and aggression-induced Fos responses, do not lie within the classical avian CG, but in the laterally adjacent intercollicular nucleus (ICo, suggesting that much of the ICo is homologous to the dorsal PAG.

  16. Position-specific isotope modeling of organic micropollutants transformation through different reaction pathways.

    Science.gov (United States)

    Jin, Biao; Rolle, Massimo

    2016-03-01

    The degradation of organic micropollutants occurs via different reaction pathways. Compound specific isotope analysis is a valuable tool to identify such degradation pathways in different environmental systems. We propose a mechanism-based modeling approach that provides a quantitative framework to simultaneously evaluate concentration as well as bulk and position-specific multi-element isotope evolution during the transformation of organic micropollutants. The model explicitly simulates position-specific isotopologues for those atoms that experience isotope effects and, thereby, provides a mechanistic description of isotope fractionation occurring at different molecular positions. To demonstrate specific features of the modeling approach, we simulated the degradation of three selected organic micropollutants: dichlorobenzamide (BAM), isoproturon (IPU) and diclofenac (DCF). The model accurately reproduces the multi-element isotope data observed in previous experimental studies. Furthermore, it precisely captures the dual element isotope trends characteristic of different reaction pathways as well as their range of variation consistent with observed bulk isotope fractionation. It was also possible to directly validate the model capability to predict the evolution of position-specific isotope ratios with available experimental data. Therefore, the approach is useful both for a mechanism-based evaluation of experimental results and as a tool to explore transformation pathways in scenarios for which position-specific isotope data are not yet available.

  17. The relevance of different trust models for representation in patient organizations: conceptual considerations.

    Science.gov (United States)

    Gerhards, Helene; Jongsma, Karin; Schicktanz, Silke

    2017-07-11

    Trust within organizations is important for ensuring members' acceptance of the organization's activities and to expand their scope of action. Remarkably, Patient Organizations (POs) that often both function as a forum for self-help and represent patients on the health-political level, have been understudied in this respect. This paper analyzes the relation between trust and representation in POs. We distinguish between two models of representation originating from political theory: the trustee and delegate model and between two types of trust: horizontal and vertical trust. Our theoretical approach is illustrated with an analysis of 13 interviews with representatives of German POs. We have found that the delegate model requires horizontal trust and the trustee model vertical trust. Both models: horizontal/delegate and vertical/trustee exist within single POs. The representation process within POs demands a balancing act between inclusion of affected persons and strategically aggregating a clear-cut political claim. Trust plays in that process of coming from individual wishes to collective and political standpoints a major role both in terms of horizontal as well as vertical trust. Horizontal trust serves the communication between affected members, and vertical trust allows representatives to be decisive.

  18. Dosimetric treatment course simulation based on a statistical model of deformable organ motion.

    Science.gov (United States)

    Söhn, M; Sobotta, B; Alber, M

    2012-06-21

    We present a method of modeling dosimetric consequences of organ deformation and correlated motion of adjacent organ structures in radiotherapy. Based on a few organ geometry samples and the respective deformation fields as determined by deformable registration, principal component analysis (PCA) is used to create a low-dimensional parametric statistical organ deformation model (Söhn et al 2005 Phys. Med. Biol. 50 5893-908). PCA determines the most important geometric variability in terms of eigenmodes, which represent 3D vector fields of correlated organ deformations around the mean geometry. Weighted sums of a few dominating eigenmodes can be used to simulate synthetic geometries, which are statistically meaningful inter- and extrapolations of the input geometries, and predict their probability of occurrence. We present the use of PCA as a versatile treatment simulation tool, which allows comprehensive dosimetric assessment of the detrimental effects that deformable geometric uncertainties can have on a planned dose distribution. For this, a set of random synthetic geometries is generated by a PCA model for each simulated treatment course, and the dose of a given treatment plan is accumulated in the moving tissue elements via dose warping. This enables the calculation of average voxel doses, local dose variability, dose-volume histogram uncertainties, marginal as well as joint probability distributions of organ equivalent uniform doses and thus of TCP and NTCP, and other dosimetric and biologic endpoints. The method is applied to the example of deformable motion of prostate/bladder/rectum in prostate IMRT. Applications include dosimetric assessment of the adequacy of margin recipes, adaptation schemes, etc, as well as prospective 'virtual' evaluation of the possible benefits of new radiotherapy schemes.

  19. Modeling of organic pollutant destruction in a stirred-tank reactor by ozonation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Destruction of organic contaminants in water by ozonation is a gas-liquid process which involves ozone mass transfer and fast irreversible chemical reactions. Ozonation reactor design and process optimizing require the modeling of the gas-liquid interactions within the reactor. In this paper a theoretical model combining the fluid dynamic and reaction kineticparameters is proposed for predicting the destruction rates of organic pollutants in a semi-batch stirred-tank reactor by ozonation. A simple expression for the enhancement factor as ourprevious work (Cheng, 2000) has been applied to evaluate the chemical mass transfer coefficient in ozone absorption.2,4-dichlorophenol (2,4-DCP) and 2,6-DCP or their mixture are chosen as the model compounds for simulating, and the predicted DCP oundation item: The National Natural Science Foundation of China (No. 20006006) ncentrations are compared with some measured data.

  20. Optical modeling of sunlight by using partially coherent sources in organic solar cells.

    Science.gov (United States)

    Alaibakhsh, Hamzeh; Darvish, Ghafar

    2016-03-01

    We investigate the effects of coherent and partially coherent sources in optical modeling of organic solar cells. Two different organic solar cells are investigated: one without substrate and the other with a millimeter-sized glass substrate. The coherent light absorption is calculated with rigorous coupled-wave analysis. The result of this method is convolved with a distribution function to calculate the partially coherent light absorption. We propose a new formulation to accurately model sunlight as a set of partially coherent sources. In the structure with glass substrate, the accurate sunlight modeling results in the elimination of coherent effects in the thick substrate, but the coherency in other layers is not affected. Using partially coherent sources instead of coherent sources for simulations with sunlight results in a smoother absorption spectrum, but the change in the absorption efficiency is negligible.