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Sample records for alternative host matrix

  1. A two-matrix alternative

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří

    2013-01-01

    Roč. 26, 15 December (2013), s. 836-841. ISSN 1537-9582 Institutional support: RVO:67985807 Keywords : two-matrix alternative * solution * algorithm Subject RIV: BA - General Math ematics Impact factor: 0.514, year: 2013 http://www. math .technion.ac.il/iic/ela/ela-articles/articles/vol26_pp836-841.pdf

  2. Insects as alternative hosts for phytopathogenic bacteria.

    Science.gov (United States)

    Nadarasah, Geetanchaly; Stavrinides, John

    2011-05-01

    Phytopathogens have evolved specialized pathogenicity determinants that enable them to colonize their specific plant hosts and cause disease, but their intimate associations with plants also predispose them to frequent encounters with herbivorous insects, providing these phytopathogens with ample opportunity to colonize and eventually evolve alternative associations with insects. Decades of research have revealed that these associations have resulted in the formation of bacterial-vector relationships, in which the insect mediates dissemination of the plant pathogen. Emerging research, however, has highlighted the ability of plant pathogenic bacteria to use insects as alternative hosts, exploiting them as they would their primary plant host. The identification of specific bacterial genetic determinants that mediate the interaction between bacterium and insect suggests that these interactions are not incidental, but have likely arisen following the repeated association of microorganisms with particular insects over evolutionary time. This review will address the biology and ecology of phytopathogenic bacteria that interact with insects, including the traditional role of insects as vectors, as well as the newly emerging paradigm of insects serving as alternative primary hosts. Also discussed is one case where an insect serves as both host and vector, which may represent a transitionary stage in the evolution of insect-phytopathogen associations. PMID:21251027

  3. Survival of Colletotrichum acutatum on alternative hosts

    OpenAIRE

    Parikka, Päivi; Lemmetty, Anne

    2009-01-01

    To detect possibilities for weeds to transfer the pathogen from infected plants to a second crop, the susceptibility of some alternate hosts was studied. Altogether 18 annual and perennial weed species common on strawberry fields were inoculated in greenhouse with spore suspension of C. acutatum.

  4. An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms. 1998 annual progress report

    International Nuclear Information System (INIS)

    'Certain high level wastes (HLW) in the US contain components such as phosphates, heavy metals, and halides which make them poorly suited for disposal in borosilicate glasses. Iron phosphate glasses appear to be a technically feasible alternative to borosilicate glasses for vitrifying these HLWs. The iron phosphate glasses mentioned above and their nuclear wasteforms are relatively new, so little is known about their atomic structure, redox equilibria, structure-property relationships, and crystallization products and characteristics. The objective of this research is to gain such information for the binary iron-phosphate glasses as well as iron phosphate wasteforms so that a comprehensive scientific assessment can be made of their usefulness in nuclear waste disposal. This report summarizes the work undertaken and completed in the first 20 months of a three year project. Approximately 250 samples, binary iron phosphate glasses and iron phosphate glasses containing one or two common nuclear waste components such as UO2 , Na2O, Bi2O3 , Cs2O, SrO, and MoO3, have been prepared. Weight loss has been used to measure the chemical durability and the redox equilibria between Fe(II) and Fe(III) has been investigated using Moessbauer spectroscopy. The atomic structure has been investigated using a variety of techniques including Mossbauer, Raman, X-ray absorption (XAS), and X-ray photoelectron (XPS) spectroscopies and neutron/high energy X-ray scattering. Glass forming and crystallization characteristics have been investigated using differential thermal analysis (DTA). In addition, information necessary for glass manufacturing such as suitable refractories and Joule heating parameters also have been obtained.'

  5. FUETAP concrete - an alternative radioactive waste host

    International Nuclear Information System (INIS)

    These tailored autoclaved concretes (FUETAP concentrates) offer a number of advantages as hosts for a wide variety of radioactive wastes. They are formed at low temperatures and pressures (1000C and 0.1 MPa) from readily available raw materials and require no new processing technology. The extreme latitude in concrete formulations ensures the acceptance of the gamut of waste materials. The leachability of nuclides from the resulting ceramic-like concretes is quite low with essentially no prospect of pressure build-up from long-term self-irradiation in the final storage containers. The solids are thermally stable up to at least 9000C. Additional studies are in progress to verify that FUETAP concretes are acceptable alternative waste hosts for defense, TRU, and commercial high-level radioactive waste. (orig.)

  6. Dentin matrix degradation by host Matrix Metalloproteinases: inhibition and clinical perspectives towards regeneration.

    OpenAIRE

    CatherineChaussain; leotjaderhane; AnneGeorge; SuzanneMenashi

    2013-01-01

    Bacterial enzymes have long been considered solely accountable for the degradation of the dentin matrix during the carious process. However, the emerging literature suggests that host-derived enzymes, and in particular the matrix metalloproteinases (MMPs) contained in dentin and saliva can play a major role in this process by their ability to degrade the dentin matrix from within. These findings are important since they open new therapeutic options for caries prevention and treatment. The pos...

  7. Host Matrix Modulation by Tumor Exosomes Promotes Motility and Invasiveness

    Directory of Open Access Journals (Sweden)

    Wei Mu

    2013-08-01

    Full Text Available Exosomes are important intercellular communicators, where tumor exosomes (TEX severely influence hematopoiesis and premetastatic organ cells. With the extracellular matrix (ECM being an essential constituent of non-transformed tissues and tumors, we asked whether exosomes from a metastatic rat tumor also affect the organization of the ECM and whether this has consequences on host and tumor cell motility. TEX bind to individual components of the ECM, the preferential partner depending on the exosomes' adhesion molecule profile such that high CD44 expression is accompanied by hyaluronic acid binding and high α6β4 expression by laminin (LN 332 binding, which findings were confirmed by antibody blocking. TEX can bind to the tumor matrix already during exosome delivery but also come in contact with distinct organ matrices. Being rich in proteases, TEX modulate the ECM as demonstrated for degradation of collagens, LNs, and fibronectin. Matrix degradation by TEX has severe consequences on tumor and host cell adhesion, motility, and invasiveness. By ECM degradation, TEX also promote host cell proliferation and apoptosis resistance. Taken together, the host tissue ECM modulation by TEX is an important factor in the cross talk between a tumor and the host including premetastatic niche preparation and the recruitment of hematopoietic cells. Reorganization of the ECM by exosomes likely also contributes to organogenesis, physiological and pathologic angiogenesis, wound healing, and clotting after vessel disruption.

  8. Alternating proximal gradient method for nonnegative matrix factorization

    CERN Document Server

    Xu, Yangyang

    2011-01-01

    Nonnegative matrix factorization has been widely applied in face recognition, text mining, as well as spectral analysis. This paper proposes an alternating proximal gradient method for solving this problem. With a uniformly positive lower bound assumption on the iterates, any limit point can be proved to satisfy the first-order optimality conditions. A Nesterov-type extrapolation technique is then applied to accelerate the algorithm. Though this technique is at first used for convex program, it turns out to work very well for the non-convex nonnegative matrix factorization problem. Extensive numerical experiments illustrate the efficiency of the alternating proximal gradient method and the accleration technique. Especially for real data tests, the accelerated method reveals high superiority to state-of-the-art algorithms in speed with comparable solution qualities.

  9. The Role of Host-derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

    OpenAIRE

    Zhang, Shan-chuan; Kern, Matthias

    2009-01-01

    Dentin matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which migh...

  10. Anorthite glass: a potential host matrix for 90Sr pencil

    International Nuclear Information System (INIS)

    With rising global concerns over health hazards, environmental pollution and possible malicious applications of radioactive materials, there is an increasing consciousness among public and Governmental agencies for its better control, accounting and security. Investigations carried out by International Atomic Energy Agency and other monitoring bodies reveal that among various radioactive materials, the easily dispersible ones are high activity sealed sources (generally called radioactive pencils) used for various peaceful applications. Ideally, these sealed sources should be safely secured within specialized facilities, but in practice, it is not always done. Hence, there is a need to take an extra precautionary measure to ensure that the matrices currently used for hosting the radionuclides within sealed sources are durable enough under harsh service conditions and situations arising due to possible mishaps (accidents, misplaced, stolen etc). Among the variety of useful radionuclides, 90Sr is one which is regularly used to (i) combat bone cancer, (ii) destroy unwanted tissue on the surface of eye/skin, (iii) light up/provide energy to remotely accessible areas etc. However, due to its (i) toxicity, (ii) mobility, (iii) easy incorporation within human body, (iv) considerable half-life (∼ 29 years), (v) emission of beta (β-) particles along with high energy gamma ( γ)-rays, and (vi) retention of significant toxicity within sources even after service life, release of 90Sr poses a serious threat to the biosphere. Hence, there is a need to ensure that existing 90Sr host matrices are capable of withstanding all sorts of adversity that may arise during service and under storage/disposal

  11. An Alternating Direction Algorithm for Matrix Completion with Nonnegative Factors

    OpenAIRE

    Xu, Yangyang; Yin, Wotao; Wen, Zaiwen; Zhang, Yin

    2011-01-01

    This paper introduces an algorithm for the nonnegative matrix factorization-and-completion problem, which aims to find nonnegative low-rank matrices X and Y so that the product XY approximates a nonnegative data matrix M whose elements are partially known (to a certain accuracy). This problem aggregates two existing problems: (i) nonnegative matrix factorization where all entries of M are given, and (ii) low-rank matrix completion where nonnegativity is not required. By taking the advantages ...

  12. The multitrace matrix model: An alternative to Connes NCG and IKKT model

    CERN Document Server

    Ydri, Badis

    2016-01-01

    We present a new multitrace matrix model, which is a generalization of the real quartic one matrix model, exhibiting dynamical emergence of a fuzzy two-sphere and its non-commutative gauge theory. This provides a novel and a much simpler alternative to Connes non-commutative geometry and to the IKKT matrix model for emergent geometry in two dimensions.

  13. Alternative mechanisms of increased eggshell hardness of avian brood parasites relative to host species.

    Science.gov (United States)

    Igic, Branislav; Braganza, Kim; Hyland, Margaret M; Silyn-Roberts, Heather; Cassey, Phillip; Grim, Tomas; Rutila, Jarkko; Moskát, Csaba; Hauber, Mark E

    2011-11-01

    Obligate brood parasitic birds lay their eggs in nests of other species and parasite eggs typically have evolved greater structural strength relative to host eggs. Increased mechanical strength of the parasite eggshell is an adaptation that can interfere with puncture ejection behaviours of discriminating hosts. We investigated whether hardness of eggshells is related to differences between physical and chemical traits from three different races of the parasitic common cuckoo Cuculus canorus, and their respective hosts. Using tools developed for materials science, we discovered a novel correlate of increased strength of parasite eggs: the common cuckoo's egg exhibits a greater microhardness, especially in the inner region of the shell matrix, relative to its host and sympatric non-host species. We then tested predictions of four potential mechanisms of shell strength: (i) increased relative thickness overall, (ii) greater proportion of the structurally harder shell layers, (iii) higher concentration of inorganic components in the shell matrix, and (iv) elevated deposition of a high density compound, MgCO(3), in the shell matrix. We confirmed support only for hypothesis (i). Eggshell characteristics did not differ between parasite eggs sampled from different host nests in distant geographical sites, suggesting an evolutionarily shared microstructural mechanism of stronger parasite eggshells across diverse host-races of brood parasitic cuckoos. PMID:21561966

  14. Tick control: trapping, biocontrol, host management and other alternative strategies

    Science.gov (United States)

    Ginsberg, Howard S.

    2014-01-01

    Biology of Ticks is the most comprehensive work on tick biology and tick-borne diseases. This second edition is a multi-authored work, featuring the research and analyses of renowned experts across the globe. Spanning two volumes, the book examines the systematics, biology, structure, ecological adaptations, evolution, genomics and the molecular processes that underpin the growth, development and survival of these important disease-transmitting parasites. Also discussed is the remarkable array of diseases transmitted (or caused) by ticks, as well as modern methods for their control. This book should serve as a modern reference for students, scientists, physicians, veterinarians and other specialists. Volume I covers the biology of the tick and features chapters on tick systematics, tick life cycles, external and internal anatomy, and others dedicated to specific organ systems, specifically, the tick integument, mouthparts and digestive system, salivary glands, waste removal, salivary glands, respiratory system, circulatory system and hemolymph, fat body, the nervous and sensory systems and reproductive systems. Volume II includes chapters on the ecology of non-nidicolous and nidicolous ticks, genetics and genomics (including the genome of the Lyme disease vector Ixodes scapularis) and immunity, including host immune responses to tick feeding and tick-host interactions, as well as the tick's innate immune system that prevents and/or controls microbial infections. Six chapters cover in depth the many diseases caused by the major tick-borne pathogens, including tick-borne protozoa, viruses, rickettsiae of all types, other types of bacteria (e.g., the Lyme disease agent) and diseases related to tick paralytic agents and toxins. The remaining chapters are devoted to tick control using vaccines, acaricides, repellents, biocontrol, and, finally, techniques for breeding ticks in order to develop tick colonies for scientific study.

  15. Thermophysical processes initiated by inert-matrix-hosted nanoparticles heated by laser pulses of different durations

    Science.gov (United States)

    Kalenskii, A. V.; Zvekov, A. A.; Nikitin, A. P.; Aduev, B. P.

    2016-03-01

    In the present study, a model for the heating of inert-matrix-hosted metal nanoparticles with laser radiation taking into account the melting processes is examined. The calculations were performed using the characteristics of gold and pentaerythritol tetranitrate materials. The kinetic dependences of the temperature and molten-layer thickness on nanoparticle surface were calculated. The main non-dimensional governing parameters of the model were identified. An expression for the maximum thickness of molten layer was obtained. The results can be used in predicting the stability of nonlinear-optics devices with hosted gold nanoparticles, in raising the efficiency of hyperthermia cancer therapy, and in optimizing the optical detonators.

  16. Matrix Model for Choosing Green Marketing Sustainable Strategic Alternatives

    Directory of Open Access Journals (Sweden)

    Cătălina Sitnikov

    2015-08-01

    Full Text Available Green marketing examines the symbiotic role played by marketing in ensuring sustainable business, exploring issues concerning the environment and the way strategic decisions can influence it. At present, the environmental issues concern more and more the competitive approach any organization can implement. Based on this approach, organizations can gain competitive advantage by managing environmental variables and by developing and implementing green marketing strategies. Considering the importance and impact of green marketing, by using theoretical concepts and defining a set of research directions, the paper and the research conducted were focused on creating a matrix model for choosing the optimal green marketing strategy, oriented towards competitive advantage. The model is based on the correlation that can be established among the generic strategies of competitive advantage, the variables of extended marketing mix (7Ps and the green marketing strategy matrix. There are also analyzed the implications that may be generated within a company by the adoption of a green marketing strategy and its role in promoting the environmental benefits of products.

  17. Experimental transmission of a microsporidian pathogen from mosquitoes to an alternate copepod host.

    OpenAIRE

    Andreadis, T G

    1985-01-01

    Meiospores of a microsporidian parasite Amblyospora sp. (Protozoa: Microspora) from larval Aedes cantator mosquitoes were directly infectious to an alternate copepod host, Acanthocyclops vernalis (Arthropoda: Crustacea). Infections ranged from 6.7% to 60.0% in laboratory tests when meiospores and copepods were maintained together for 10-30 days in filtered water from the breeding site or in a balanced salt solution. Pathogen development takes place within host adipose tissue and is fatal to t...

  18. Host-Parasite Interaction: Parasite-Derived and -Induced Proteases That Degrade Human Extracellular Matrix

    Directory of Open Access Journals (Sweden)

    Carolina Piña-Vázquez

    2012-01-01

    Full Text Available Parasitic protozoa are among the most important pathogens worldwide. Diseases such as malaria, leishmaniasis, amoebiasis, giardiasis, trichomoniasis, and trypanosomiasis affect millions of people. Humans are constantly threatened by infections caused by these pathogens. Parasites engage a plethora of surface and secreted molecules to attach to and enter mammalian cells. The secretion of lytic enzymes by parasites into host organs mediates critical interactions because of the invasion and destruction of interstitial tissues, enabling parasite migration to other sites within the hosts. Extracellular matrix is a complex, cross-linked structure that holds cells together in an organized assembly and that forms the basement membrane lining (basal lamina. The extracellular matrix represents a major barrier to parasites. Therefore, the evolution of mechanisms for connective-tissue degradation may be of great importance for parasite survival. Recent advances have been achieved in our understanding of the biochemistry and molecular biology of proteases from parasitic protozoa. The focus of this paper is to discuss the role of protozoan parasitic proteases in the degradation of host ECM proteins and the participation of these molecules as virulence factors. We divide the paper into two sections, extracellular and intracellular protozoa.

  19. Search for alternate hosts of the coconut Cape Saint Paul Wilt Disease pathogen

    Directory of Open Access Journals (Sweden)

    Yankey Egya Ndede

    2009-03-01

    Full Text Available Lethal Yellowing disease locally called Cape Saint Paul wilt disease (CSPWD is the bane of the coconut industry in Ghana and is caused by a phytoplasma. In Ghana, there are areas where the disease has re-infected re-plantings long after decimating all the palms in the area. This brings to the fore the possibility of alternate hosts in the spread of the disease because the pathogen is an obligate parasite. In this work, a number of plants were screened for their host status to the CSPWD pathogen. The presence of phytoplasmas in these plants was tested by polymerase chain reaction analysis using universal phytoplasma primers P1/P7 and CSPWD-specific primers G813/GAKSR. Although Desmodium adscendens tested positive to the CSPWD-specific primers, cloning and sequencing did not confirm it as an alternate host. The identification of alternate hosts will help us to evolve sound control strategies against the spread of the disease.

  20. An alternative S-matrix for N = 6 Chern-Simons theory?

    International Nuclear Information System (INIS)

    We have recently proposed an S-matrix for the planar limit of the N = 6 superconformal Chern-Simons theory of Aharony, Bergman, Jafferis and Maldacena which leads to the all-loop Bethe ansatz equations conjectured by Gromov and Vieira. An unusual feature of this proposal is that the scattering of A and B particles is reflectionless. We consider here an alternative S-matrix, for which A-B scattering is not reflectionless. We argue that this S-matrix does not lead to the Bethe ansatz equations which are consistent with perturbative computations.

  1. Modelling the effect of an alternative host population on the spread of citrus Huanglongbing

    Science.gov (United States)

    d'A. Vilamiu, Raphael G.; Ternes, Sonia; Laranjeira, Francisco F.; de C. Santos, Tâmara T.

    2013-10-01

    The objective of this work was to model the spread of citrus Huanglongbing (HLB) considering the presence of a population of alternative hosts (Murraya paniculata). We developed a compartmental deterministic mathematical model for representing the dynamics of HLB disease in a citrus orchard, including delays in the latency and incubation phases of the disease in the plants and a delay period on the nymphal stage of Diaphorina citri, the insect vector of HLB in Brazil. The results of numerical simulations indicate that alternative hosts should not play a crucial role on HLB dynamics considering a typical scenario for the Recôncavo Baiano region in Brazil . Also, the current policy of removing symptomatic plants every three months should not be expected to significantly hinder HLB spread.

  2. Jackknife resampling technique on mocks: an alternative method for covariance matrix estimation

    CERN Document Server

    Escoffier, S; Tilquin, A; Pisani, A; Aguichine, A; de la Torre, S; Ealet, A; Gillard, W; Jullo, E

    2016-01-01

    We present a fast and robust alternative method to compute covariance matrix in case of cosmology studies. Our method is based on the jackknife resampling applied on simulation mock catalogues. Using a set of 600 BOSS DR11 mock catalogues as a reference, we find that the jackknife technique gives a similar galaxy clustering covariance matrix estimate by requiring a smaller number of mocks. A comparison of convergence rates show that $\\sim$7 times fewer simulations are needed to get a similar accuracy on variance. We expect this technique to be applied in any analysis where the number of available N-body simulations is low.

  3. Testing constancy of the error covariance matrix in vector models against parametric alternatives using a spectral decomposition

    OpenAIRE

    Yang, Yukai

    2014-01-01

    I consider multivariate (vector) time series models in which the error covariance matrix may be time-varying. I derive a test of constancy of the error covariance matrix against the alternative that the covariance matrix changes over time. Idesign a new family of Lagrange-multiplier tests against the alternative hypothesis that the innovations are time-varying according to several parametric specifications. I investigate the size and power properties of these tests and find that the test with...

  4. An emission model as an alternative to o-d matrix in urban goods transport modelling

    OpenAIRE

    González-Feliu, Jesús; Cedillo-Campo, Miguel Gastón; García-Alcaraz, Jorge Luis

    2014-01-01

    This paper presents an alternative method to O-D matrix for estimating road occupancy of urban goods movement (UGM). The originality of the model arises on three elements. The first is that the modelling unit is the delivery operation, with all the elements that are associated to it. The second is that it follows an inductive approach, starting from a rich database, to define different generation functions without a priori applying a defined mathematical framework. The third is that the model...

  5. Host Alternation of Chikungunya Virus Increases Fitness while Restricting Population Diversity and Adaptability to Novel Selective Pressures

    OpenAIRE

    Coffey, L. L.; Vignuzzi, M.

    2011-01-01

    The mechanisms by which RNA arboviruses, including chikungunya virus (CHIKV), evolve and maintain the ability to infect vertebrate and invertebrate hosts are poorly understood. To understand how host specificity shapes arbovirus populations, we studied CHIKV populations passaged alternately between invertebrate and vertebrate cells (invertebrate ↔ vertebrate) to simulate natural alternation and contrasted the results with those for populations that were artificially released from cycling by p...

  6. Remineralization of demineralized bone matrix (DBM) via alternating solution immersion (ASI).

    Science.gov (United States)

    Soicher, Matthew A; Christiansen, Blaine A; Stover, Susan M; Leach, J Kent; Fyhrie, David P

    2013-10-01

    In order to achieve successful clinical outcomes, biomaterials used for bone grafts must possess a number of traits including biocompatibility and osteoconductivity. These materials must also demonstrate appropriate mechanical stability to withstand handling as well as support potentially significant stresses at the implant site. Synthetic and natural polymer scaffolds used for bone tissue engineering (BTE) often lack necessary mechanical properties. Our goal was to internally mineralize natural collagenous matrix, thereby increasing mechanical properties of the material to useful levels. Published methods for intrafibrillar collagen mineralization were applied to clinically relevant-sized constructs but did not successfully deposit mineral in the interior of the constructs. To address this limitation, we developed a new technique for the remineralization of demineralized bone matrix (DBM) based on alternating solution immersion, or ASI. Mineral was removed from equine bone specimens, leaving behind a demineralized bone matrix (DBM). This matrix provides a framework for the nucleation and growth of a replacement mineral phase. Plain film radiography and microcomputed tomography (microCT) indicated accumulation of mineral within the DBM, and mechanical testing (3 point bending and compression) revealed a significant increase in stiffness between the DBM and the remineralized bone matrix (RBM). We believe this remineralization process will be useful in the preparation of stiff and strong allografts for clinical application. PMID:23759125

  7. Testing Local Host Adaptation and Phenotypic Plasticity in a Herbivore When Alternative Related Host Plants Occur Sympatrically

    OpenAIRE

    Ruiz-Montoya, Lorena; Núñez-Farfán, Juan

    2013-01-01

    Host race formation in phytophagous insects can be an early stage of adaptive speciation. However, the evolution of phenotypic plasticity in host use is another possible outcome. Using a reciprocal transplant experiment we tested the hypothesis of local adaptation in the aphid Brevicoryne brassicae. Aphid genotypes derived from two sympatric host plants, Brassica oleracea and B. campestris, were assessed in order to measure the extent of phenotypic plasticity in morphological and life history...

  8. Testing local host adaptation and phenotypic plasticity in a herbivore when alternative related host plants occur sympatrically.

    Directory of Open Access Journals (Sweden)

    Lorena Ruiz-Montoya

    Full Text Available Host race formation in phytophagous insects can be an early stage of adaptive speciation. However, the evolution of phenotypic plasticity in host use is another possible outcome. Using a reciprocal transplant experiment we tested the hypothesis of local adaptation in the aphid Brevicoryne brassicae. Aphid genotypes derived from two sympatric host plants, Brassica oleracea and B. campestris, were assessed in order to measure the extent of phenotypic plasticity in morphological and life history traits in relation to the host plants. We obtained an index of phenotypic plasticity for each genotype. Morphological variation of aphids was summarized by principal components analysis. Significant effects of recipient host on morphological variation and life history traits (establishment, age at first reproduction, number of nymphs, and intrinsic growth rate were detected. We did not detected genotype × host plant interaction; in general the genotypes developed better on B. campestris, independent of the host plant species from which they were collected. Therefore, there was no evidence to suggest local adaptation. Regarding plasticity, significant differences among genotypes in the index of plasticity were detected. Furthermore, significant selection on PC1 (general aphid body size on B. campestris, and on PC1 and PC2 (body length relative to body size on B. oleracea was detected. The elevation of the reaction norm of PC1 and the slope of the reaction norm for PC2 (i.e., plasticity were under directional selection. Thus, host plant species constitute distinct selective environments for B. brassicae. Aphid genotypes expressed different phenotypes in response to the host plant with low or nil fitness costs. Phenotypic plasticity and gene flow limits natural selection for host specialization promoting the maintenance of genetic variation in host exploitation.

  9. Host-Mediated Bioactivation of Pyrazinamide: Implications for Efficacy, Resistance, and Therapeutic Alternatives

    Science.gov (United States)

    Via, Laura E.; Savic, Rada; Weiner, Danielle M.; Zimmerman, Matthew D.; Prideaux, Brendan; Irwin, Scott M.; Lyon, Eddie; O’Brien, Paul; Gopal, Pooja; Eum, Seokyong; Lee, Myungsun; Lanoix, Jean-Philippe; Dutta, Noton K.; Shim, TaeSun; Cho, Jeong Su; Kim, Wooshik; Karakousis, Petros C.; Lenaerts, Anne; Nuermberger, Eric; Barry, Clifton E.; Dartois, Véronique

    2015-01-01

    Pyrazinamide has played a critical role in shortening therapy against drug-sensitive, drug-resistant, active, and latent tuberculosis (TB). Despite widespread recognition of its therapeutic importance, the sterilizing properties of this 60-year-old drug remain an enigma given its rather poor activity in vitro. Here we revisit longstanding paradigms and offer pharmacokinetic explanations for the apparent disconnect between in vitro activity and clinical impact. We show substantial host-mediated conversion of prodrug pyrazinamide (PZA) to the active form, pyrazinoic acid (POA), in TB patients and in animal models. We demonstrate favorable penetration of this pool of circulating POA from plasma into lung tissue and granulomas, where the pathogen resides. In standardized growth inhibition experiments, we show that POA exhibits superior in vitro potency compared to PZA, indicating that the vascular supply of host-derived POA may contribute to the in vivo efficacy of PZA, thereby reducing the apparent discrepancy between in vitro and in vivo activity. However, the results also raise the possibility that subinhibitory concentrations of POA generated by the host could fuel the emergence of resistance to both PZA and POA. In contrast to widespread expectations, we demonstrate good oral bioavailability and exposure in preclinical species in pharmacokinetic studies of oral POA. Baseline exposure of oral POA can be further increased by the xanthine oxidase inhibitor and approved gout drug allopurinol. These promising results pave the way for clinical investigations of oral POA as a therapeutic alternative or an add-on to overcome PZA resistance and salvage this essential TB drug. PMID:26086040

  10. AN ALTERNATIVE HOST MATRIX BASED ON IRON PHOSPHATE GLASSES FOR THE VITRIFICATION OF SPECIALIZED WASTE FORMS

    International Nuclear Information System (INIS)

    As mentioned above, the overall goal of this research project was to collect the scientific information essential to develop iron phosphate glass based nuclear wasteforms. The specific objectives of the project were: (1) Investigate the structure of binary iron phosphate glasses and it's dependence on the composition and melting atmosphere: Understand atomic arrangements and nature of the bonding. Establish structure-property relationships. Determine the compositions and melting conditions which optimize the critical properties of the base glass. (2) Understand the structure of iron phosphate wasteforms and it's dependence on the composition and melting atmosphere: Investigate how the waste elements are bonded and coordinated within the glass structure. Establish structure-property relationships for the waste glasses. Determine the compositions and melting atmosphere for which the critical properties of the waste forms would be optimum. (3) Determine the role(s) played by the valence states of iron ions and it's dependence on the composition and melting atmosphere: Understand the different roles of iron(II) and iron(III) ions in determining the critical properties of the base glass and the waste forms. Investigate how the iron valence and its significance depend on the composition and melting atmosphere. (4) Investigate glass forming and crystallization processes of the iron phosphate glasses and their waste forms: Understand the dependence of the glass forming and crystallization characteristics on overall glass composition and valence states of iron ions. Identify the products of devitrification and investigate the critical properties of these crystalline compounds which may adversely affect the chemical and physical properties of the waste forms

  11. Evaluation of Jatropha curcas as an alternative host of African cassava mosaic virus

    International Nuclear Information System (INIS)

    A study was conducted to evaluate ten local accessions of Jatropha curcas L. (physic nut) as an alternative host of African cassava mosaic virus (ACMV). The ten local accessions of J. curcas were planted in a field trial at the research farm of the Biotechnology and Nuclear Agriculture Research Institute, intercropped with ACMV-infected cassava cultivar 'Afisiafi' and left to natural spread of ACMV from the cassava to J. curcas. The J. curcas plants which became infected generally showed mild symptoms, with severity ranging from 1.00 at eight weeks after planting (WAP) to 3.00 at 16 WAP on a scale of 1 (no symptoms) to 5 (severe symptoms). Whitefly populations recorded on the J. curcas accessions in the wet (Sept. - Oct., 2008) and dry (Jan. - Feb., 2009) seasons were generally low. However, significant differences (p < 0.05) were found in the mean whitefly numbers found on the individual J. curcas accessions in the dry season. Disease incidence as determined by symptom expression varied among accessions at eight, twelve and sixteen weeks after planting, though the differences not statistically significant. Leaf samples from the ten J. curcas accessions were tested at six, nine and twelve months after planting (MAP) for the presence of ACMV by enzyme-linked immunosorbent assays (ELISA) and by polymerase chain reaction (PCR). ELISA tests using monoclonal antibody SCRI 33, in a double antibody sandwich ELISA (DAS-ELISA) showed ACMV infection in the J. curcas accessions. Infection ranged from 0% at 6MAP to 50% at 12MAP. Molecular analysis by PCR with a virus-specific primer (JSP001/JSP002) of the viral DNA extracted from leaves of the number of samples tested, as against 37.7% by ELISA. Infection among the accessions as shown by to PCR varied significantly (p < 0.05) and ranged from as low as 16.6% to as high as 91.6%. ACMV infection of the J. curcas plants was further confirmed by infectivity tests on Nicotiana benthamiana indicator plants. Three of (3) out of 132

  12. Interpretation of drug concentrations in an alternative matrix: the case of meprobamate in vitreous humor.

    Science.gov (United States)

    Bévalot, Fabien; Gustin, Marie-Paule; Cartiser, Nathalie; Le Meur, Catherine; Malicier, Daniel; Fanton, Laurent

    2011-05-01

    The use of vitreous humor (VH) as an alternative matrix to blood in the field of forensic toxicology has been described for numerous drugs. Interpretation of drug concentrations measured in VH, as in other matrices, requires statistical analysis of a data set obtained on a significant series. In the present study, two diagnostic tests interpreting postmortem VH concentrations of meprobamate in 117 sets of autopsy data are reported. (1) A VH meprobamate concentration threshold of 28 mg/l was statistically equivalent to that of blood meprobamate concentration threshold of 50 mg/l distinguishing overdose from therapeutic use in blood. The intrinsic qualities of the test were good, with sensitivity of 0.95 and absolute specificity of 1. (2) A novel interpretation tool is proposed, allowing blood concentration range to be evaluated, with a known probability, from VH concentration. PMID:21337124

  13. Tenebrio molitor (Coleoptera: Tenebrionidae) as an alternative host to study fungal infections.

    Science.gov (United States)

    de Souza, Patrícia Canteri; Morey, Alexandre Tadachi; Castanheira, Gabriel Marcondes; Bocate, Karla Paiva; Panagio, Luciano Aparecido; Ito, Fabio Augusto; Furlaneto, Márcia Cristina; Yamada-Ogatta, Sueli Fumie; Costa, Idessânia Nazareth; Mora-Montes, Hector Manuel; Almeida, Ricardo Sergio

    2015-11-01

    Models of host–pathogen interactions are crucial for the analysis of microbial pathogenesis. In this context, invertebrate hosts, including Drosophila melanogaster (fruit fly), Caenorhabditis elegans (nematode) and Galleria mellonella (moth), have been used to study the pathogenesis of fungi and bacteria. Each of these organisms offers distinct benefits in elucidating host–pathogen interactions. In this study,we present a newinvertebrate infection model to study fungal infections: the Tenebrio molitor (beetle) larvae. Here we performed T. molitor larvae infection with one of two important fungal human pathogens, Candida albicans or Cryptococcus neoformans, and analyzed survival curves and larva infected tissues.We showed that increasing concentrations of inoculum of both fungi resulted in increased mortality rates, demonstrating the efficiency of the method to evaluate the virulence of pathogenic yeasts. Additionally, following 12 h post-infection, C. albicans formsmycelia, spreading its hyphae through the larva tissue,whilst GMS stain enabled the visualization of C. neoformans yeast and theirmelanin capsule. These larvae are easier to cultivate in the laboratory than G. mellonella larvae, and offer the same benefits. Therefore, this insect model could be a useful alternative tool to screen clinical pathogenic yeast strainswith distinct virulence traits or different mutant strains. PMID:26453946

  14. Rapid host defense against Aspergillus fumigatus involves alveolar macrophages with a predominance of alternatively activated phenotype.

    Directory of Open Access Journals (Sweden)

    Shikha Bhatia

    Full Text Available The ubiquitous fungus Aspergillus fumigatus is associated with chronic diseases such as invasive pulmonary aspergillosis in immunosuppressed patients and allergic bronchopulmonary aspergillosis (ABPA in patients with cystic fibrosis or severe asthma. Because of constant exposure to this fungus, it is critical for the host to exercise an immediate and decisive immune response to clear fungal spores to ward off disease. In this study, we observed that rapidly after infection by A. fumigatus, alveolar macrophages predominantly express Arginase 1 (Arg1, a key marker of alternatively activated macrophages (AAMs. The macrophages were also found to express Ym1 and CD206 that are also expressed by AAMs but not NOS2, which is expressed by classically activated macrophages. The expression of Arg1 was reduced in the absence of the known signaling axis, IL-4Rα/STAT6, for AAM development. While both Dectin-1 and TLR expressed on the cell surface have been shown to sense A. fumigatus, fungus-induced Arg1 expression in CD11c(+ alveolar macrophages was not dependent on either Dectin-1 or the adaptor MyD88 that mediates intracellular signaling by most TLRs. Alveolar macrophages from WT mice efficiently phagocytosed fungal conidia, but those from mice deficient in Dectin-1 showed impaired fungal uptake. Depletion of macrophages with clodronate-filled liposomes increased fungal burden in infected mice. Collectively, our studies suggest that alveolar macrophages, which predominantly acquire an AAM phenotype following A. fumigatus infection, have a protective role in defense against this fungus.

  15. Role of Berberis spp. as alternate hosts in generating new races of Puccinia graminis and P. striiformis

    Science.gov (United States)

    The common barberry and several other Berberis spp. serve as the alternate hosts to two important rust pathogens of small grains and grasses, Puccinia graminis and P. striiformis. Barberry eradication has been practiced for centuries as a means to control stem rust. Diverse virulence variations have...

  16. Century-old Mystery of Puccinia striiformis Life History Solved with the Identification of Berberis as an Alternate Host

    Science.gov (United States)

    The life history of Puccinia striiformis remains a mystery because the alternate host has never been found. Inoculation of grasses using aeciospores from naturally infected Berberis chinensis and B. koreana resulted in infection on Poa pratensis, producing uredinia typical of stripe rust caused by P...

  17. CD44 alternative splicing in gastric cancer cells is regulated by culture dimensionality and matrix stiffness.

    Science.gov (United States)

    Branco da Cunha, Cristiana; Klumpers, Darinka D; Koshy, Sandeep T; Weaver, James C; Chaudhuri, Ovijit; Seruca, Raquel; Carneiro, Fátima; Granja, Pedro L; Mooney, David J

    2016-08-01

    Two-dimensional (2D) cultures often fail to mimic key architectural and physical features of the tumor microenvironment. Advances in biomaterial engineering allow the design of three-dimensional (3D) cultures within hydrogels that mimic important tumor-like features, unraveling cancer cell behaviors that would not have been observed in traditional 2D plastic surfaces. This study determined how 3D cultures impact CD44 alternative splicing in gastric cancer (GC) cells. In 3D cultures, GC cells lost expression of the standard CD44 isoform (CD44s), while gaining CD44 variant 6 (CD44v6) expression. This splicing switch was reversible, accelerated by nutrient shortage and delayed at lower initial cell densities, suggesting an environmental stress-induced response. It was further shown to be dependent on the hydrogel matrix mechanical properties and accompanied by the upregulation of genes involved in epithelial-mesenchymal transition (EMT), metabolism and angiogenesis. The 3D cultures reported here revealed the same CD44 alternative splicing pattern previously observed in human premalignant and malignant gastric lesions. These findings indicate that fundamental features of 3D cultures - such as soluble factors diffusion and mechanical cues - influence CD44 expression in GC cells. Moreover, this study provides a new model system to study CD44 dysfunction, whose role in cancer has been in the spotlight for decades. PMID:27187279

  18. Volatile fragrances associated with flowers mediate the host plant alternation of a polyphagous mirid bug

    Science.gov (United States)

    Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is an important insect pest of cotton, fruit trees and other crops in China, and exhibits a particularly broad host range. Adult A. lucorum greatly prefers host plants at the flowering stage, and their populations track flowering plants both spatiall...

  19. Immigration of susceptible hosts triggers the evolution of alternative parasite defence strategies.

    Science.gov (United States)

    Chabas, Hélène; van Houte, Stineke; Høyland-Kroghsbo, Nina Molin; Buckling, Angus; Westra, Edze R

    2016-08-31

    Migration of hosts and parasites can have a profound impact on host-parasite ecological and evolutionary interactions. Using the bacterium Pseudomonas aeruginosa UCBPP-PA14 and its phage DMS3vir, we here show that immigration of naive hosts into coevolving populations of hosts and parasites can influence the mechanistic basis underlying host defence evolution. Specifically, we found that at high levels of bacterial immigration, bacteria switched from clustered regularly interspaced short palindromic repeats (CRISPR-Cas) to surface modification-mediated defence. This effect emerges from an increase in the force of infection, which tips the balance from CRISPR to surface modification-based defence owing to the induced and fixed fitness costs associated with these mechanisms, respectively. PMID:27581884

  20. Music as Engaging, Educational Matrix: Exploring the Case of Marginalised Students Attending an "Alternative" Music Industry School

    Science.gov (United States)

    Cleaver, David; Riddle, Stewart

    2014-01-01

    "Harmony High" is an alternative school where music functions as an educational magnet to attract marginalised students who have disengaged from the mainstream. Through an investigation of the student perspective, we discover that while acting as a magnet, music also becomes the educational matrix or "heart and soul" that helps…

  1. Hospedeiros alternativos de Xanthomonas campestris pv. viticola Alternative hosts of Xanthomonas campestris pv. viticola

    Directory of Open Access Journals (Sweden)

    Ana Rosa Peixoto

    2007-04-01

    Full Text Available Xanthomonas campestris pv. viticola (Xcv, que causa o cancro bacteriano da videira, sobrevive em plantas infectadas, epifiticamente em órgãos da parte aérea e pode ser veiculada em mudas e/ou bacelos infectados. O trabalho teve como objetivo investigar possíveis hospedeiros alternativos do patógeno, visando fornecer subsídios para o manejo da doença. A partir das plantas invasoras Alternanthera tenella, Amaranthus sp., Glycine sp. e Senna obtusifolia com sintomas similares aos do cancro bacteriano da videira, coletadas em parreirais de Juazeiro e Petrolina, no Submédio São Francisco, foram isoladas bactérias semelhantes a Xcv. No entanto, nenhuma bactéria foi isolada de plantas de Commelina benghalensis e Azadirachta indica com sintomas semelhantes. A patogenicidade dos isolados bacterianos obtidos foi confirmada em plantas de A. tenella, Amaranthus sp., Glycine sp., S. obtusifolia e em mudas de videira cv. Red Globe, em condições de casa de vegetação. As plantas invasoras Chamaesyce hirta, Dactyloctenium aegyptium, Eragrostis pilosa e Pilea sp., inoculadas artificialmente com os isolados Xcv1 e UnB1216, também desenvolveram sintomas típicos do cancro bacteriano.Xanthomonas campestris pv. viticola (Xcv, which causes the bacterial canker of grapevine, survives in infected plants as an epiphyte on aerial plant parts and may be carried in infected transplants and/or cuttings. This study was performed to investigate putative alternative hosts of the pathogen, aiming to find support for disease management. Bacteria similar to Xcv were isolated from the weeds Alternanthera tenella, Amaranthus sp., Glycine sp. and Senna obtusifolia showing canker-like symptoms and collected in vineyards of Juazeiro and Petrolina at the Submédio São Francisco. No bacteria were isolated from Commelina benghalensis and Azadirachta indica showing similar symptoms. The pathogenicity of the isolates was confirmed in plants of A. tenella, Amaranthus sp

  2. Population Diversity ofPuccinia graminis is Sustained Through Sexual Cycle on Alternate Hosts

    Institute of Scientific and Technical Information of China (English)

    Yue Jin; Matt Rouse; Jim Groth

    2014-01-01

    A high degree of virulence diversity has been maintained in the population ofPuccinia graminis f. sp.tritici (Pgt) in northwestern United States. AlthoughBerberis vulgaris is present in the region andPgthas been isolated from aecial infections onB. vulgaris, the population is too diverse to be explained by the limited presence ofB. vulgaris alone. Since 2008, we have isolatedP. graminis from aecial infections on fruits ofMahonia repens andMahonia aquifolium from northwestern United States. These two native woody shrub species, widely distributed in western North America, were once classiifed as resistant to P. graminis based on artiifcial inoculations. By isolatingP. graminis from aecia, we established that M. repens andM. aquifolium along withB. vulgaris (albeit infrequent) serve as the alternate hosts ofP. graminis in the region. The isolates ofP. graminis from Mahonia of North America had diverse virulence patterns and most of the isolates could be differentiated on Morocco, Line E, Chinese Spring, Little Club, LMPG-6, Rusty, and other genotypes that are considered to be universally susceptible to mostPgt isolates. This discovery explained the persistence of virulence diversity ofPgt observed in isolates derived from uredinia on cereal crops in the region. In addition to cereal crops, uredinial stage of theP. graminis population is sustained by wild grasses, especiallyElymus glaucus, a native grass sharing the same habitat with the rusted Mahonia spp. Although virulence to some important stem rust resistance genes was observed in some isolates derived from Mahonia of North America when tested against single stem rust resistance gene stocks, the overall virulence is very limited in these isolates. This is likely a result of limited selection pressure on the rust population. In contrast to northwestern United Sates, thePgt population in east of the Rocky Mountains of North America has declined steadily with a single race, QFCSC, being predominant in the last

  3. Survival and larval development of Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) on alternatives host

    International Nuclear Information System (INIS)

    Two bioassays were conducted to evaluate the suitability of host plants of fall armyworm (FAW), Spodoptera frugiperda (J E Smith), in the Brazilian agro-ecosystem. Larval development and survival were analyzed by infesting leaves of maize, grain sorghum, Johnson grass, soybean, Brachiaria and tobacco with FAW newly hatched larvae in a no choice test. No significant differences of survival were observed among insects reared on different hosts, except for tobacco, where no survivors were recorded. Larvae fed on soybean and artificial diet grew larger than those fed on the other hosts. The heaviest pupa was observed from larva fed on artificial diet and the lighter from larva fed on Brachiaria grass. No significant differences were reported on larval development time on natural hosts, but it was longer for larvae reared on artificial diet. Three classes of larval development time were observed on maize, four on sorghum, Brachiaria and soybean, and five on artificial diet. Nearly 85% of FAW larvae completed development within 12 d on maize; 77% on grain sorghum, 80% on Johnson grass, 68% on Brachiaria and 83% on soybean within 14 d and 69% on artificial diet within 17 d. The host suitability to FAW decreases from maize to sorghum, soybean and Brachiaria. (author)

  4. An Alternative Method for Computing Mean and Covariance Matrix of Some Multivariate Distributions

    Science.gov (United States)

    Radhakrishnan, R.; Choudhury, Askar

    2009-01-01

    Computing the mean and covariance matrix of some multivariate distributions, in particular, multivariate normal distribution and Wishart distribution are considered in this article. It involves a matrix transformation of the normal random vector into a random vector whose components are independent normal random variables, and then integrating…

  5. A bacterial pathogen uses distinct type III secretion systems to alternate between host kingdoms

    Science.gov (United States)

    Plant and animal-pathogenic bacteria utilize phylogenetically distinct type III secretion systems (T3SS) that produce needle-like injectisomes or pili for the delivery of effector proteins into host cells. Pantoea stewartii subsp. stewartii (Pnss), the causative agent of Stewart’s bacterial wilt and...

  6. Byrsonima crassifolia (MALPIGHIACEAE): NEW ALTERNATE HOST TO CARAMBOLA FRUIT FLY IN BRAZIL

    OpenAIRE

    Cristiane Ramos de Jesus-Barros; Orimax Monteiro Cruz; Ricardo Adaime

    2015-01-01

    Fruits of Byrsonima crassifolia (Malpighiaceae) are reported for the first time as hosts of Bactrocera carambolae (Diptera: Tephritidae) in Brazil.   Keywords: Bactrocera carambolae, quarantine pest, Amazon, murici.   DOI: http://dx.doi.org/10.18561/2179-5746/biotaamazonia.v5n3p117-118

  7. Hospedeiros alternativos de Acidovorax avenae subsp. citrulli Alternative hosts of Acidovorax avenae subsp. citrulli

    Directory of Open Access Journals (Sweden)

    Ana Rosa P. Nascimento

    2004-09-01

    Full Text Available Uma das principais doenças que afeta o meloeiro é a mancha-aquosa, causada pela bactéria Acidovorax avenae subsp. citrulli (Aac. Visando conhecer hospedeiros alternativos de Aac, plantas no estágio de primeiras folhas definitivas, de várias espécies/cultivares, incluindo cucurbitáceas, solanáceas, gramíneas, leguminosas e caricáceas, foram inoculadas pela atomização da parte aérea com suspensão dos isolados Aac 1.49 e Aac 12.13, oriundos de melão e melancia, respectivamente. A suscetibilidade das plantas aos isolados foi avaliada pelo período de incubação (PI e incidência da doença (INC. Caupi, feijão, fumo e milho não apresentaram sintomas. Os menores PIs foram observados em cucurbitáceas (3,0 d, com exceção da bucha (6,83 d. Incidências da doença acima de 90% foram observadas em cucurbitáceas, excetuando a bucha e em solanáceas, para ambos os isolados de Aac. Em outro experimento, frutos de abóbora, abobrinha, berinjela, mamão, maxixe, melancia, melão, pepino, pimentão e tomate foram analisados quanto à suscetibilidade aos isolados Aac 1.49 e Aac 12.13. Os frutos foram inoculados pelo método de injeção subepidérmica, determinando-se PI, INC e severidade, avaliada pelo diâmetro da lesão externa (DLE e profundidade da lesão (PL. Menores PIs (2,0 d foram detectados em frutos de mamão, melancia, melão e pimentão. Incidência de 100% foi observada em todos os frutos inoculados, com exceção da abobrinha (93,75% e da abóbora (34,37%. Maiores DLEs foram observados em pepino (1,47 cm para o isolado Aac 1.49 e em melancia (1,60 cm e melão (1,07 cm para Aac 12.13. As maiores PL foram constatadas em melancia (1,72 e 0,75 cm respectivamente para Aac 1.49 e Aac 12.13. Frutos de berinjela não apresentaram sintomas externos embora as lesões internas tenham sido profundas.One of the most important melon diseases is the bacterial blotch caused by Acidovorax avenae subsp. citrulli (Aac. Alternative hosts of this

  8. Matrix metalloproteinase-9 deficiency impairs host defense mechanisms against Streptococcus pneumoniae in a mouse model of bacterial meningitis.

    Science.gov (United States)

    Böttcher, Tobias; Spreer, Annette; Azeh, Ivo; Nau, Roland; Gerber, Joachim

    2003-03-01

    Matrix metalloproteinase-9 (MMP-9) appears to contribute to blood-brain barrier damage and neuronal injury in bacterial meningitis. To further explore the function of MMP-9 in meningeal inflammation, we injected 10(4) colony forming units (CFU) of a Streptoccocus pneumoniae type 3 strain into the right forebrain of MMP-9 deficient mice (MMP-9(-/-), n=16) and wild-type controls (129 x B6, n=15). The clinical course of the disease, leukocyte recruitment into the subarachnoid space and bacterial titers in the brain did not differ. Yet, clearance of the bacteria from blood (log CFU/ml 4.7 [3.8/5.4] vs. 3.6 [3.0/4.0]; P=0.005) and spleen homogenates (log CFU/ml 5.3 [4.8/5.5] vs. 4.0 [2.8/4.7]; P=0.01) was reduced in MMP-9 deficient mice. A reduced systemic bacterial clearance of MMP-9(-/-) mice was confirmed in experimental S. pneumoniae peritonitis/sepsis. This implies a compromised systemic, but not intracerebral host response against S. pneumoniae in MMP-9 deficiency. PMID:12581831

  9. Putative alternative polyadenylation (APA events in the early interaction of Salmonella enterica Typhimurium and human host cells

    Directory of Open Access Journals (Sweden)

    Fabian Afonso-Grunz

    2015-12-01

    Full Text Available The immune response of epithelial cells upon infection is mediated by changing activity levels of a variety of proteins along with changes in mRNA, and also ncRNA abundance. Alternative polyadenylation (APA represents a mechanism that diversifies gene expression similar to alternative splicing. T-cell activation, neuronal activity, development and several human diseases including viral infections involve APA, but at present it remains unclear if this mechanism is also implicated in the response to bacterial infections. Our recently published study of interacting Salmonella enterica Typhimurium and human host cells includes genome-wide expression profiles of human epithelial cells prior and subsequent to infection with the invasive pathogen. The generated dataset (GEO accession number: GSE61730 covers several points of time post infection, and one of these interaction stages was additionally profiled with MACE-based dual 3'Seq, which allows for identification of polyadenylation (PA sites. The present study features the polyadenylation landscape in early interacting cells based on this data, and provides a comparison of the identified PA sites with those of a corresponding 3P-Seq dataset of non-interacting cells. Differential PA site usage of FTL, PRDX1 and VAPA results in transcription of mRNA isoforms with distinct sets of miRNA and protein binding sites that influence processing, localization, stability, and translation of the respective mRNA. APA of these candidate genes consequently harbors the potential to modulate the host cell response to bacterial infection.

  10. Leishmania amazonensis promastigotes in 3D Collagen I culture: an in vitro physiological environment for the study of extracellular matrix and host cell interactions

    Directory of Open Access Journals (Sweden)

    Debora B. Petropolis

    2014-04-01

    Full Text Available Leishmania amazonensis is the causative agent of American cutaneous leishmaniasis, an important neglected tropical disease. Once Leishmania amazonensis is inoculated into the human host, promastigotes are exposed to the extracellular matrix (ECM of the dermis. However, little is known about the interaction between the ECM and Leishmania promastigotes. In this study we established L. amazonensis promastigote culture in a three-dimensional (3D environment mainly composed of Collagen I (COL I. This 3D culture recreates in vitro some aspects of the human host infection site, enabling the study of the interaction mechanisms of L. amazonensis with the host ECM. Promastigotes exhibited “freeze and run” migration in the 3D COL I matrix, which is completely different from the conventional in vitro swimming mode of migration. Moreover, L. amazonensis promastigotes were able to invade, migrate inside, and remodel the 3D COL I matrix. Promastigote trans-matrix invasion and the freeze and run migration mode were also observed when macrophages were present in the matrix. At least two classes of proteases, metallo- and cysteine proteases, are involved in the 3D COL I matrix degradation caused by Leishmania. Treatment with a mixture of protease inhibitors significantly reduced promastigote invasion and migration through this matrix. Together our results demonstrate that L. amazonensis promastigotes release proteases and actively remodel their 3D environment, facilitating their migration. This raises the possibility that promastigotes actively interact with their 3D environment during the search for their cellular “home”—macrophages. Supporting this hypothesis, promastigotes migrated faster than macrophages in a novel 3D co-culture model.

  11. Oral Fluid as an Alternative Matrix to Monitor Opiate and Cocaine Use in Substance-Abuse Treatment Patients

    OpenAIRE

    Dams, Riet; Choo, Robin E.; Lambert, Willy E.; Jones, Hendree; Huestis, Marilyn A.

    2006-01-01

    Interest in oral fluid as an alternative matrix for monitoring drug use is due to its ease-of-collection and non-invasiveness; however, limited data are available on the disposition of drugs into oral fluid. The objective of this research was to provide data on the presence and concentrations of heroin, cocaine and multiple metabolites in oral fluid after illicit opioid and cocaine use. Thrice weekly oral fluid specimens (N=403) from 16 pregnant opiate-dependent women were obtained with the S...

  12. Alternating optimization method based on nonnegative matrix factorizations for deep neural networks

    OpenAIRE

    Sakurai, Tetsuya; Imakura, Akira; Inoue, Yuto; Futamura, Yasunori

    2016-01-01

    The backpropagation algorithm for calculating gradients has been widely used in computation of weights for deep neural networks (DNNs). This method requires derivatives of objective functions and has some difficulties finding appropriate parameters such as learning rate. In this paper, we propose a novel approach for computing weight matrices of fully-connected DNNs by using two types of semi-nonnegative matrix factorizations (semi-NMFs). In this method, optimization processes are performed b...

  13. Transfer of toxin genes to alternate bacterial hosts for mosquito control

    Directory of Open Access Journals (Sweden)

    Sergio Orduz

    1995-02-01

    Full Text Available Mosquitoes are vector of serious human and animal diseases, such as malaria, dengue, yellow fever, among others. The use of biological control agents has provide an environmentally safe and highly specific alternative to the use of chemical insecticides in the control of vector borne diseases. Bacillus thuringiensis and B. sphaericus produce toxic proteins to mosquito larvae. Great progress has been made on the biochemical and molecular characterization of such proteins and the genes encoding them. Nevertheless, the low residuality of these biological insecticides is one of the major drawbacks. This article present some interesting aspects of the mosquito larvae feeding habits and review the attempts that have been made to genetically engineer microorganisms that while are used by mosquito larvae as a food source should express the Bacillus toxin genes in order to improve the residuality and stability in the mosquito breeding ponds.

  14. Using Complementary and Alternative Medicines to Target the Host Response during Severe Influenza

    Directory of Open Access Journals (Sweden)

    Lisa M. Alleva

    2010-01-01

    Full Text Available It is now accepted that an overwhelming inflammatory response is the cause of human deaths from avian H5N1 influenza infection. With this in mind we sought to examine the literature for examples of complementary and alternative medicines that reduce inflammation, and to place the results of this search in the context of our own work in a mouse model of influenza disease, using a pharmaceutical agent with anti-inflammatory properties. Two Chinese herbs, Angelica sinensis (Dang Gui and Salvia miltiorrhiza (Danshen, have been recently shown to protect mice during lethal experimental sepsis via inhibition of the novel inflammatory cytokine High Mobility Group Box 1 protein (HMGB1. Biochanin A, a ligand of the peroxisome proliferator activated receptors (PPAR alpha and gamma and the active isoflavone in Trifolium pratense (red clover, has anti-inflammatory properties, and thus could be used as an influenza treatment. This is of great interest since we have recently shown that gemfibrozil, a drug used to treat hyperlipidemia in humans and a synthetic ligand of PPAR alpha, significantly reduces the mortality associated with influenza infections in mice. The inflammation-modulating abilities of these natural agents should be considered in light of what is now known about the mechanisms of fatal influenza, and tested as potential candidates for influenza treatments in their own right, or as adjunct treatments to antivirals.

  15. Interposition Porcine Acellular Dermal Matrix Xenograft Successful Alternative in Treatment for Massive Rotator Cuff

    Science.gov (United States)

    Neumann, Julie; Zgonis, Miltiadis H.; Reay, Kathleen Dolores; Mayer, Stephanie W.; Boggess, Blake; Toth, Alison P.

    2016-01-01

    Objectives: Despite advances in the surgical techniques of rotator cuff repair (RCR), the management of massive rotator cuff tears in shoulders without glenohumeral arthritis poses a difficult problem for surgeons. Failure of massive rotator cuff repairs range from 20-90% at one to two years postoperatively using arthrography, ultrasound, or magnetic resonance imaging. Additionally, there are inconsistent outcomes reported with debridement alone of massive rotator cuff tears as well as limitations seen with other current methods of operative intervention including arthroplasty and tendon transfers. The purpose of this prospective, comparative study was to determine if the repair of massive rotator cuff tears using an interposition porcine acellular dermal matrix xenograft improves subjective function, pain, range of motion, and strength at greater than two years follow-up. To our knowledge, this is the largest prospective series reporting outcomes of using porcine acellular dermal matrix xenograft as an interposition graft. Methods: Thirty-seven patients (37 shoulders) with an average age of 66 years (range 51-80 years) were prospectively followed for 33 months (range 23-48) following massive RCR using porcine acellular dermal matrix interposition xenograft. Subjective outcomes were measured using the Visual Analog Scale (VAS) pain score (0-10, 0 = no pain), Modified American Shoulder and Elbow Score (M-ASES), and Short-Form12 (SF-12) scores. Preoperative and postoperative objective outcome measures included active range of motion and supraspinatus and infraspinatus manual muscle strength. Postoperative outcome measures included quantitative muscle strength using a dynamometer and static and dynamic ultrasonography to assess the integrity of the repair. Results: Average VAS pain score decreased from 4.5 to 1.1 (Pacellular dermal matrix xenografts, patients had significant improvement in pain, range of motion, strength and reported good subjective function based on

  16. Interpretation of drug concentrations in an alternative matrix: the case of meprobamate in bile.

    Science.gov (United States)

    Fanton, L; Bevalot, F; Gustin, M P; Paultre, C Z; Le Meur, C; Malicier, D

    2009-03-01

    Investigating toxicological causes of death may require alternative matrices when the usual ones are lacking. Whereas forensic toxicology uses bile almost only for xenobiotic screening, a diagnostic test interpreting postmortem bile concentrations of meprobamate is reported. Based on 128 sets of autopsy data, its intrinsic qualities were good, with 0.95 sensitivity and 0.93 specificity. In a French forensic population, the positive and negative predictive factors were 0.90 and 0.97, respectively. It is a useful means of revealing overdoses where blood samples are not available or of confirming blood tests when postmortem redistribution is suspected. PMID:18581126

  17. An alternative approach for assessment of liquid chromatography-mass spectrometry matrix effects using auto-sampler programmed co-injection.

    Science.gov (United States)

    Rogers, Caitlyn A; Stockham, Peter C; Nash, Christine M; Martin, Sheridan M; Kostakis, Chris; Lenehan, Claire E

    2016-03-01

    We report the use of auto-sampler programmable functions to co-inject analyte standard solution and matrix extract to assess ion enhancement and suppression (matrix effects) in LC-MS. This is effectively an automated post-extraction addition (APEA) procedure, emulating the manual post-extraction addition (PEA) approach widely adopted for assessment of matrix effects. To verify that APEA was comparable to the conventional PEA approach, matrix effects were determined using both methods for a selection of 31 illicit and pharmaceutical drugs in 10 different human urine extracts. Matrix effects measured using APEA were statistically indistinguishable from manual PEA methodology for 27 of the 31 drugs. Of the four drugs that showed significant differences using the two methods, three differed by less than 2 %, which is within the expected accuracy limits required for matrix effect determinations. The remaining analyte, trimeprazine, was found to degrade in the spiked PEA matrix extract, accounting for the difference between matrix effects measured by the PEA and APEA approaches. APEA enables a single matrix extract to be assessed at multiple analyte concentrations, resulting in a considerable reduction in sample preparation time. In addition, APEA can reduce the quantity of analyte-free sample matrix required for matrix effect assessment, which is an important consideration in certain analytical and bioanalytical fields. This work shows that APEA may be considered as an acceptable alternative to PEA for the assessment of matrix effects in LC-MS method validation and may be applicable to a variety of matrices such as environmental samples. Graphical abstract A graphical representation of the procedure used to compare manual post extraction addition (PEA) and auto-sampler programmed co-injection (APEA) to assess matrix effects in LCMS. PMID:26781099

  18. Revisiting the notion of Origin-Destination Traffic Matrix of the Hosts that are attached to a Switched Local Area Network

    Directory of Open Access Journals (Sweden)

    Monday Eyinagho

    2011-12-01

    Full Text Available There is a widely held notion in the literature that there is an origin-destination traffic matrix for all thehosts (end nodes that are attached to any switched local area network. This is usually in relation to theneed to calculate the end-to-end (or maximum end-to-end delays between all the end nodes that areattached to the network, for the sole purpose of using these delays values to design upper-bounded delayswitched local area networks, in efforts at solving the delay problems of this class of networks. In thispaper, we show that this notion of origin-destination traffic matrix for all the hosts that are attached to aswitched local area network does not seem to be correct

  19. Decoding Biomass-Sensing Regulons of Clostridium thermocellum Alternative Sigma-I Factors in a Heterologous Bacillus subtilis Host System.

    Directory of Open Access Journals (Sweden)

    Iván Muñoz-Gutiérrez

    Full Text Available The Gram-positive, anaerobic, cellulolytic, thermophile Clostridium (Ruminiclostridium thermocellum secretes a multi-enzyme system called the cellulosome to solubilize plant cell wall polysaccharides. During the saccharolytic process, the enzymatic composition of the cellulosome is modulated according to the type of polysaccharide(s present in the environment. C. thermocellum has a set of eight alternative RNA polymerase sigma (σ factors that are activated in response to extracellular polysaccharides and share sequence similarity to the Bacillus subtilis σI factor. The aim of the present work was to demonstrate whether individual C. thermocellum σI-like factors regulate specific cellulosomal genes, focusing on C. thermocellum σI6 and σI3 factors. To search for putative σI6- and σI3-dependent promoters, bioinformatic analysis of the upstream regions of the cellulosomal genes was performed. Because of the limited genetic tools available for C. thermocellum, the functionality of the predicted σI6- and σI3-dependent promoters was studied in B. subtilis as a heterologous host. This system enabled observation of the activation of 10 predicted σI6-dependent promoters associated with the C. thermocellum genes: sigI6 (itself, Clo1313_2778, xyn11B (Clo1313_0522, xyn10D (Clo1313_0177, xyn10Z (Clo1313_2635, xyn10Y (Clo1313_1305, cel9V (Clo1313_0349, cseP (Clo1313_2188, sigI1 (Clo1313_2174, cipA (Clo1313_0627, and rsgI5 (Clo1313_0985. Additionally, we observed the activation of 4 predicted σI3-dependent promoters associated with the C. thermocellum genes: sigI3 (itself, Clo1313_1911, pl11 (Clo1313_1983, ce12 (Clo1313_0693 and cipA. Our results suggest possible regulons of σI6 and σI3 in C. thermocellum, as well as the σI6 and σI3 promoter consensus sequences. The proposed -35 and -10 promoter consensus elements of σI6 are CNNAAA and CGAA, respectively. Additionally, a less conserved CGA sequence next to the C in the -35 element and a highly

  20. The effects of host derived metalloproteinases on dentin bond and the role of MMPs inhibitors on dentin matrix degradation

    Science.gov (United States)

    LONGHI, M.; CERRONI, L.; CONDÒ, S.G.; ARIANO, V.; PASQUANTONIO, G.

    2014-01-01

    SUMMARY Objectives. The work has the objective to analyze the literature on the degradation of the adhesive interface. In particular the study is focused on the role of the metalloproteinase in the hydrolytic degradation of collagen matrix in the bonded interface. The survey will concern also the latest innovations to improve and increase the link between dentin and the restorative materials through the MMPs inhibitors. Methods. The research has been carried out in the MEDLINE database by choosing keywords as “metalloproteinases” and “dentin bond” and “degradation”. In vitro studies were included in the research, excluding studies with no human and deciduous teeth. Language was limited to English. Results. The collagenolytic enzymes in mineralized dentin have been demonstrated to have an important role in dental hard tissue pathologies, including the degradation of the hybrid layer. Conclusion. The preservation of the collagen matrix integrity is a key issue in the attempts to improve the dentin bonding durability. PMID:25992261

  1. Thermal requirements of Trichogramma pretiosum and T. acacioi (Hym.: Trichogrammatidae), parasitoids of the avocado defoliator Nipteria panacea (Lep.: Geometridae), in eggs of two alternative hosts

    OpenAIRE

    Dirceu Pratissoli; José Cola Zanuncio; Ulysses Rodrigues Vianna; Josimar Souza Andrade; Tobias Baruc Moreira Pinon; Gilberto Santos Andrade

    2005-01-01

    This research studied the thermal requirements of Trichogramma pretiosum and T. acacioi (Hymenoptera: Trichogrammatidae), parasitoids of Nipteria panacea (Lepidoptera: Geometridae), with eggs of the alternative hosts Anagasta kuehniella (Lepidoptera: Pyralidae) and Sitotroga cerealella (Lepidoptera: Gelechiidae) aiming to use these natural enemies in biological control programs of this pest in avocado orchards. T. pretiosum needed 151.83 and 160.04 degree-days, above threshold of 10.70 and 10...

  2. Tilted Orientation of Photochromic Dyes with Guest-Host Effect of Liquid Crystalline Polymer Matrix for Electrical UV Sensing

    Science.gov (United States)

    Ranjkesh, Amid; Park, Min-Kyu; Park, Do Hyuk; Park, Ji-Sub; Choi, Jun-Chan; Kim, Sung-Hoon; Kim, Hak-Rin

    2015-01-01

    We propose a highly oriented photochromic dye film for an ultraviolet (UV)-sensing layer, where spirooxazine (SO) derivatives are aligned with the liquid crystalline UV-curable reactive mesogens (RM) using a guest-host effect. For effective electrical UV sensing with a simple metal-insulator-metal structure, our results show that the UV-induced switchable dipole moment amount of the SO derivatives is high; however, their tilting orientation should be controlled. Compared to the dielectric layer with the nearly planar SO dye orientation, the photochromic dielectric layer with the moderately tilted dye orientation shows more than seven times higher the UV-induced capacitance variation. PMID:26729116

  3. Synthesis of diluted magnetic semiconductor Bi2−xMnxTe3 nanocrystals in a host glass matrix

    International Nuclear Information System (INIS)

    Diluted magnetic semiconductors of manganese doped in bismuth-telluride nanocrystals (Bi2−xMnxTe3 NCs) were grown in a glass matrix and investigated by Transmission Electron Microscopy, X-Ray Diffraction, Atomic Force Microscopy/Magnetic Force Microscopy, and Electron Paramagnetic Resonance. TEM images showed that the nanocrystals formed within the glass matrix were nearly spherical, with average sizes between 4 and 5 nm, and d015-spacing of approximately 0.322 nm, which corresponds to the (015) interplanar distance in Bi2Te3 bulk. The diffraction patterns showed that the diffraction peak associated with the (015) plane of the Bi2−xMnxTe3 nanocrystals shifts to larger diffraction angles as manganese (Mn) concentration increases, suggesting that the Mn2+ ions are substitutional defects occupying Bi sites (MnBi). AFM and MFM measurements showed magnetic phase contrast patterns, providing further evidence of Mn2+ ion incorporation in the nanocrystal structure. EPR signal of manganese ion incorporation and valence states in the crystalline structure of the Bi2Te3 nanocrystals confirmed the presence of the Mn2+ state. - Highlights: • Bi2−xMnxTe3 NCs were synthesized in a glass matrix by fusion method. • Transmission Electronic Microscopy shows the formation of Bi2−xMnxTe3 NCs. • The sp-d exchange interaction in DMS NCs can be evidenced by X Ray-Diffraction and Magnetic Force Microscopy. • Electron Paramagnetic Resonance spectra confirmed that Mn2+ ions are located in two distinct Bi2Te3 NCs sites

  4. A Sheet-like Carbon Matrix Hosted Sulfur as Cathode for High-performance Lithium-Sulfur Batteries.

    Science.gov (United States)

    Lu, Songtao; Chen, Yan; Zhou, Jia; Wang, Zhida; Wu, Xiaohong; Gu, Jian; Zhang, Xiaoping; Pang, Aimin; Jiao, Zilong; Jiang, Lixiang

    2016-01-01

    Lithium-sulfur (Li-S) batteries are a promising candidate of next generation energy storage systems owing to its high theoretical capacity and energy density. However, to date, its commercial application was hindered by the inherent problems of sulfur cathode. Additionally, with the rapid decline of non-renewable resources and active appeal of green chemistry, the intensive research of new electrode materials was conducted worldwide. We have obtained a sheet-like carbon material (shaddock peel carbon sheets SPCS) from organic waste shaddock peel, which can be used as the conductive carbon matrix for sulfur-based cathodes. Furthermore, the raw materials are low-cost, truly green and recyclable. As a result, the sulfur cathode made with SPCS (SPCS-S), can deliver a high reversible capacity of 722.5 mAh g(-1) at 0.2 C after 100 cycles with capacity recuperability of ~90%, demonstrating that the SPCS-S hybrid is of great potential as the cathode for rechargeable Li-S batteries. The high electrochemical performance of SPCS-S hybrid could be attributed to the sheet-like carbon network with large surface area and high conductivity of the SPCS, in which the carbon sheets enable the uniform distribution of sulfur, better ability to trap the soluble polysulfides and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles. PMID:26842015

  5. A Sheet-like Carbon Matrix Hosted Sulfur as Cathode for High-performance Lithium-Sulfur Batteries

    Science.gov (United States)

    Lu, Songtao; Chen, Yan; Zhou, Jia; Wang, Zhida; Wu, Xiaohong; Gu, Jian; Zhang, Xiaoping; Pang, Aimin; Jiao, Zilong; Jiang, Lixiang

    2016-02-01

    Lithium-sulfur (Li-S) batteries are a promising candidate of next generation energy storage systems owing to its high theoretical capacity and energy density. However, to date, its commercial application was hindered by the inherent problems of sulfur cathode. Additionally, with the rapid decline of non-renewable resources and active appeal of green chemistry, the intensive research of new electrode materials was conducted worldwide. We have obtained a sheet-like carbon material (shaddock peel carbon sheets SPCS) from organic waste shaddock peel, which can be used as the conductive carbon matrix for sulfur-based cathodes. Furthermore, the raw materials are low-cost, truly green and recyclable. As a result, the sulfur cathode made with SPCS (SPCS-S), can deliver a high reversible capacity of 722.5 mAh g-1 at 0.2 C after 100 cycles with capacity recuperability of ~90%, demonstrating that the SPCS-S hybrid is of great potential as the cathode for rechargeable Li-S batteries. The high electrochemical performance of SPCS-S hybrid could be attributed to the sheet-like carbon network with large surface area and high conductivity of the SPCS, in which the carbon sheets enable the uniform distribution of sulfur, better ability to trap the soluble polysulfides and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles.

  6. Size and porosity effects on thermal conductivity of nanoporous material with an extension to nanoporous particles embedded in a host matrix

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim, E-mail: H.Machrafi@ulg.ac.be; Lebon, Georgy

    2015-06-05

    A formula for the effective thermal conductivity of nanoporous media is derived, following a thermodynamic approach. An extension to nanocomposites composed of a homogeneous matrix wherein porous nanoparticles are dispersed is proposed as well. The originality of the model is that it is based on extended irreversible thermodynamics, a theory specifically designed for sub-scaled systems. Two different situations are discussed: in the first one, nanoporous silicon with spherical porous inclusions of micro-, meso- and macro-dimension respectively is considered. The description is validated by comparison with experimental data and five other models. Analysis of the results shows an excellent agreement of our theoretical approach with experiments in the whole range of porous radii, from 2 to 100 nm. In the second part of the work, thermal conductivity of porous silicon nanoparticles embedded in a germanium host matrix is investigated. The coupled influence of the pore and nanoparticles sizes is emphasized. - Highlights: • Original extended irreversible thermodynamic model for thermal conductivity in nanoporous systems. • Validation by experimental data and comparison with five other models. • Physical interpretation of size and porosity dependence of the thermal conductivity. • Extension to porous nanocomposites.

  7. Size and porosity effects on thermal conductivity of nanoporous material with an extension to nanoporous particles embedded in a host matrix

    International Nuclear Information System (INIS)

    A formula for the effective thermal conductivity of nanoporous media is derived, following a thermodynamic approach. An extension to nanocomposites composed of a homogeneous matrix wherein porous nanoparticles are dispersed is proposed as well. The originality of the model is that it is based on extended irreversible thermodynamics, a theory specifically designed for sub-scaled systems. Two different situations are discussed: in the first one, nanoporous silicon with spherical porous inclusions of micro-, meso- and macro-dimension respectively is considered. The description is validated by comparison with experimental data and five other models. Analysis of the results shows an excellent agreement of our theoretical approach with experiments in the whole range of porous radii, from 2 to 100 nm. In the second part of the work, thermal conductivity of porous silicon nanoparticles embedded in a germanium host matrix is investigated. The coupled influence of the pore and nanoparticles sizes is emphasized. - Highlights: • Original extended irreversible thermodynamic model for thermal conductivity in nanoporous systems. • Validation by experimental data and comparison with five other models. • Physical interpretation of size and porosity dependence of the thermal conductivity. • Extension to porous nanocomposites

  8. Novel nitrogen-doped hierarchically porous coralloid carbon materials as host matrixes for lithium–sulfur batteries

    International Nuclear Information System (INIS)

    Highlights: • Nitrogen-doped hierarchically porous coralloid carbon/sulfur composites were prepared • Nitrogen atoms were introduced to improve electrochemical properties • The intriguing structural features benefited discharge capacity and cycling stability - Abstract: Nitrogen-doped hierarchically porous coralloid carbon/sulfur composites (N-HPCC/S) served as attractive cathode materials for lithium–sulfur (Li–S) batteries were fabricated for the first time. The nitrogen-doped hierarchically porous coralloid carbon (N-HPCC) with an appropriate nitrogen content (1.29 wt%) was synthesized via a facile hydrothermal approach, combined with subsequent carbonization–activation. The N-HPCC/S composites prepared by a simple melt–diffusion method displayed an excellent electrochemical performance. With a high sulfur content (58 wt%) in the total electrode weight, the N-HPCC/S cathode delivered a high initial discharge capacity of 1626.8 mA h g−1 and remained high up to 1086.3 mA h g−1 after 50 cycles at 100 mA g−1, which is about 1.86 times as that of activated carbon. Particularly, the reversible discharge capacity still maintained 607.2 mA h g−1 after 200 cycles even at a higher rate of 800 mA g−1. The enhanced electrochemical performance was attributed to the synergetic effect between the intriguing hierarchically porous coralloid structure and appropriate nitrogen doping, which could effectively trap polysulfides, alleviate the volume expansion, enhance the electronic conductivity and improve the surface interaction between the carbon matrix and polysulfides

  9. Microbial community analysis and identification of alternative host-specific fecal indicators in fecal and river water samples using pyrosequencing.

    Science.gov (United States)

    Jeong, Ju-Yong; Park, Hee-Deung; Lee, Kyong-Hee; Weon, Hang-Yeon; Ka, Jong-Ok

    2011-08-01

    It is important to know the comprehensive microbial communities of fecal pollution sources and receiving water bodies for microbial source tracking. Pyrosequencing targeting the V1-V3 hypervariable regions of the 16S rRNA gene was used to investigate the characteristics of bacterial and Bacteroidales communities in major fecal sources and river waters. Diversity analysis indicated that cow feces had the highest diversities in the bacterial and Bacteroidales group followed by the pig sample, with human feces having the lowest value. The Bacteroidales, one of the potential fecal indicators, totally dominated in the fecal samples accounting for 31%-52% of bacterial sequences, but much less (0.6%) in the river water. Clustering and Venn diagram analyses showed that the human sample had a greater similarity to the pig sample in the bacterial and Bacteroidales communities than to samples from other hosts. Traditional fecal indicators, i.e., Escherichia coli, were detected in the human and river water samples at very low rates and Clostridium perfringens and enterococci were not detected in any samples. Besides the Bacteroidales group, some microorganisms detected in the specific hosts, i.e., Parasutterella excrementihominis, Veillonella sp., Dialister invisus, Megamonas funiformis, and Ruminococcus lactaris for the human and Lactobacillus amylovorus and Atopostipes sp. for the pig, could be used as potential host-specific fecal indicators. These microorganisms could be used as multiple fecal indicators that are not dependent on the absence or presence of a single indicator. Monitoring for multiple indicators that are highly abundant and host-specific would greatly enhance the effectiveness of fecal pollution source tracking. PMID:21887641

  10. Organ heterogeneity of host-derived matrix metalloproteinase expression and its involvement in multiple-organ metastasis by lung cancer cell lines.

    Science.gov (United States)

    Shiraga, Minoru; Yano, Seiji; Yamamoto, Akihiko; Ogawa, Hirohisa; Goto, Hisatsugu; Miki, Toyokazu; Miki, Keisuke; Zhang, Helong; Sone, Saburo

    2002-10-15

    Cancer metastasis is tightly regulated by the interaction of tumor cells and host organ microenvironments. Matrix metalloproteinases (MMPs), produced by both tumor cells and host stromal cells, play a central role in tumor invasion and angiogenesis. We determined whether metastatic potential of lung cancer to multiple organs is dependent solely on the expression of MMPs by tumor cells, using two metastasis models of human lung cancer cell lines expressing various levels of MMPs and a MMP inhibitor (ONO-4817). In the lung metastasis model, tumor cells (PC14, PC14PE6, H226, A549) inoculated i.v. into nude or SCID mice metastasized only in the lung. In the multiple-organ metastasis model, tumor cells (RERF-LC-AI, SBC-3/DOX, H69/VP, which express low levels of MMPs) inoculated i.v. into natural killer cell-depleted SCID mice metastasized into the liver, kidneys, and systemic lymph nodes. Film in situ zymography analysis revealed that the nontumor parenchyma of the lung had no gelatinolytic activity, whereas gelatinolytic activity of the liver and kidney was high and low, respectively. In the lung metastasis model, gelatinolytic activity of lung nodules directly correlated with the in vitro expression of MMP-2 and MMP-9 by tumor cells. Inhibition of MMP activity by ONO-4817 suppressed lung metastasis by the cell lines that expressed MMPs, but not those that did not express MMP, via the inhibition of MMP activity of lung tumors. In the multiple-organ metastasis model, liver parenchyma, but not liver nodules, showed gelatinolytic activity. The MMP inhibition reduced metastasis to the liver, but not to the kidney or lymph nodes, via inhibition of MMP activity of liver parenchyma. These findings suggest that MMP expression varies among the host organ microenvironments and that stromal MMPs may promote metastasis of lung cancer. Therefore, antimetastatic effects based on MMP inhibition may be dependent on MMPs derived not only from tumor cells but also from organ

  11. Rapid determination of thiabendazole in orange extract using excitation-emission matrix fluorescence and second-order calibration based on alternating trilinear decomposition/alternating normalization-weighted error algorithms

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel approach is proposed for direct quantitative analysis of thiabendazole in the orange extract by using excitation-emission matrix fluorescence coupled with second-order calibration methods based on the alternating trilinear decomposition(ATLD) and the alternating normalization-weighted error(ANWE) algorithms,respectively. The average recoveries of thiabendazole in the orange extract by using ATLD and ANWE with an estimated component number of two were 99.7 ± 3.3% and 103.5 ± 4.1%,respectively. Furthermore,the accuracy of the two algorithms was also evaluated through elliptical joint confidence region(EJCR) tests as well as figures of merit,such as sensitivity(SEN),selectivity(SEL) and limit of detection(LOD). The experimental results demonstrate that both algorithms have been satisfactorily applied to the determination of thiabendazole in orange extract,and the perform-ance of ANWE is slightly better than that of ATLD.

  12. Rapid determination of thiabendazole in orange extract using excitation-emission matrix fluorescence and second-order calibration based on alternating trilinear decomposition/alternating normalization-weighted error algorithms

    Institute of Scientific and Technical Information of China (English)

    WANG XueMei; WU HaiLong; NIE JinFang; LI YuanNa; YU YongJie; YU RuQin

    2008-01-01

    A novel approach is proposed for direct quantitative analysis of thiabendazole in the orange extract by using excitation-emission matrix fluorescence coupled with second-order calibration methods based on the alternating trilinear decomposition (ATLD) and the alternating normalization-weighted error (ANWE) algorithms, respectively. The average recoveries of thiabendazole in the orange extract by using ATLD and ANWE with an estimated component number of two were 99.7 ± 3.3% and 103.5 ± 4.1%, respectively. Furthermore, the accuracy of the two algorithms was also evaluated through elliptical joint confidence region (EJCR) tests as well as figures of merit, such as sensitivity (SEN), selectivity (SEL) and limit of detection (LOD). The experimental results demonstrate that both algorithms have been satisfactorily applied to the determination of thiabendazole in orange extract, and the perform-ance of ANWE is slightly better than that of ATLD.

  13. Carbon isotope ratios document that the elytra of western corn rootworm (Coleoptera: Chrysomelidae) reflects adult versus larval feeding and later instar larvae prefer Bt corn to alternate hosts.

    Science.gov (United States)

    Hiltpold, Ivan; Adamczyk, John J; Higdon, Matthew L; Clark, Thomas L; Ellersieck, Mark R; Hibbard, Bruce E

    2014-06-01

    In much of the Corn Belt and parts of Europe, the western corn rootworm, Diabrotica virgifera virgifera LeConte, is the most important insect pest of maize. The need for additional basic knowledge of this pest has been highlighted while developing resistance management plans for insecticidal genetically modified crops. This study evaluated the possibility of tracking feeding habits of western corn rootworm larvae using stable carbon isotope signatures. Plants accumulate different ratios of (13)C:(12)C isotopes, usually expressed as δ(13)C, according to whether they use the C3 or C4 photosynthetic pathway. Herbivore biomass is expected to reflect the δ(13)C of the food they eat. For the current experiment, western corn rootworm larvae were grown on different species of plants exhibiting different δ(13)C values. The δ(13)C values were then measured in elytra of emerged beetles. When beetles were unfed, biomass reflected larval feeding. When beetles were fed for 31 d postemergence, δ(13)C values of elytra almost exclusively reflected adult feeding. These results suggest the use of caution in the interpretation of δ(13)C data aiming to document larval diet history when adult feeding history is unknown. The technique was also used to evaluate western corn rootworm larval choice between alternate hosts and maize with and without genetically modified (Bt) traits aimed at their control. Propensity for feeding on alternate hosts versus maize was biased toward feeding on maize regardless whether the maize had Bt or not, suggesting western corn rootworm larvae were not repelled by Bt. These data will be helpful for regulators in interpreting western corn rootworm feeding data on Bt maize. PMID:24874160

  14. Quantum confinement effect in multilayer structure of alternate CdSe and SiOx insulator matrix thinfilms

    Science.gov (United States)

    Melvin David Kumar, M.; Devadason, Suganthi

    2013-06-01

    Multilayer (ML) structure of layer-by-layer deposited CdSe/SiOx thin films and their monolayers were prepared using sequential thermal evaporation technique. X-ray diffraction study confirmed the (002) plane of CdSe with wurtzite structure. It is noticed that the microstrain, developed in ML thin films, increased with decreasing particle size. Experimentally measured band gap energies confirmed the splitting of valence band energy levels which rise due to hole confinement in CdSe. Crystallite sizes (5-7 nm) were calculated using the effective mass approximation model (i.e., Brus model) which shows that the diameter of crystallites was smaller than the Bohr exciton diameter (11.2 nm) of CdSe. The main band in the emission spectra of ML samples gradually shifted to longer wavelength side when particle size was increased from 5 to 7 nm. This is characteristic of quantum size effect. It is inferred that disorderliness in CdSe/SiOx ML thin films would increase when the thickness of CdSe sublayer is greater than that of SiOx matrix layer.

  15. A Novel and Alternative Treatment Method for Diabetic Heel Ulceration Exposing the Calcaneus Which Is Not Suitable for Flap Surgery: Vacuum Assisted Sandwich Dermal Matrix

    Directory of Open Access Journals (Sweden)

    Ugur A. Bingol

    2015-01-01

    Full Text Available Background. Currently, free flaps and pedicled flaps are the first treatment choices for large heel ulcer reconstruction. However, flap reconstruction of heel ulcerations cannot be performed in all diabetics especially with concurrent severe peripheral vascular disease because of higher flap failure rate. In recent years, the use of acellular dermal matrix (ADM has emerged as an alternative treatment option for extremity ulcers. Methods. We present 13 diabetic patients with a large heel ulceration exposing the calcaneus, who were not eligible for flap surgery due to the presence of only one patent artery of trifurcation. These cases were treated with the vacuum assisted sandwich dermal matrix (VASDEM method. Results. None of the patients required amputation. Skin grafting was successful in ten patients. Although partial losses were observed in three patients, they were healed spontaneously without surgical interventions. During the follow-up period none of the patients developed ulceration on the treatment area. All patients maintained their preoperative ambulatory ability. Conclusion. VASDEM is a novel method offering opportunity for treatment before proceeding to amputation in diabetic heel ulceration exposing the calcaneus which is not suitable for flap surgery. It also has the potential to close wounds of all sizes independent of the vessel status and wound size in selected diabetic patients.

  16. Matrix-free analysis of selected benzodiazepines in human serum samples using alternating trilinear decomposition modeling of fast liquid chromatography diode array detection data.

    Science.gov (United States)

    Vosough, Maryam; Iravani, Negar J

    2016-02-01

    This paper describes the development and validation of a simple and efficient bioanalytical procedure for simultaneous determination of alprazolam, clonazepam, diazepam in human serum samples using high performance liquid chromatography with photodiode-array detection, regarding a fast elution methodology in 4 min. Briefly, this method consists of a simple liquid extraction step of serum samples followed by HPLC analysis on a C18 column. After confirming the absence of matrix effect, an external standard methodology has been applied for quantification purposes. Due to the presence of serum endogenous components as uncalibrated components in the sample, the second-order calibration based on alternating trilinear decomposition has been applied on a set of absorbance matrices collected as a function of retention time and wavelengths. Acceptable resolution and quantification results were achieved in the presence of matrix interferences and the second-order advantage was fully exploited. The average recoveries for alprazolam, clonazepam and diazepam were 89.1%, 96.3% and 94.7% and relative standard deviation values for intra- and inter-day precision were equal or lower than 8.1% and 9.4%, respectively. The developed method enabled us to determine the analytes in the various serum samples in the presence of overlapped profiles, while keeping experimental time and extraction step at the minimum. PMID:26653472

  17. Degradation of extracellular matrix by larvae of Schistosoma mansoni. I. Degradation by cercariae as a model for initial parasite invasion of host

    Energy Technology Data Exchange (ETDEWEB)

    McKerrow, J.H.; Keene, W.E.; Jeong, K.H.; Werb, Z.

    1983-01-01

    The ability of cercariae of Schistosoma mansoni to degrade a model extracellular connective tissue matrix produced by rat vascular smooth muscle cells in culture was investigated. In this model, connective tissue macromolecules are present in the interactive framework that characterizes their structure in vivo. Cercariae were stimulated to degrade the matrix by skin lipid or linoleic acid. At the maximally stimulating concentration of linoleic acid (25 ..mu..g/cm/sup 2/), 68% of the total matrix was degraded, including 57% of the glycoprotein, 79% of the elastin, and 8% of the collagen. Degradation of matrix was inhibited by ..cap alpha../sub 1/-proteinase inhibitor and soybean trypsin inhibitor. Ethylenediaminetetraacetic acid inhibited degradation by unstimulated but not linoleic acid-stimulated cercariae. Preacetabular gland secretions collected from cercariae also degraded the matrix with an activity 86% of that of live cercariae. Preacetabular gland proteolytic activity was also inhibited by ..cap alpha../sub 1/-proteinase inhibitor, soybean trypsin inhibitor, and ethylenediaminetetraacetic acid. The similar characteristics of matrix degradation by both live cercariae and cercarial preacetabular gland secretions support the idea that a proteinase secreted from cercarial preacetabular glands facilitates invasion of skin and connective tissue by these larvae. Degradation of elastin and glycoprotein constituentes of extracellular matrix is probably essential for skin penetration.

  18. Stromal matrix metalloprotease-13 knockout alters Collagen I structure at the tumor-host interface and increases lung metastasis of C57BL/6 syngeneic E0771 mammary tumor cells

    International Nuclear Information System (INIS)

    Matrix metalloproteases and collagen are key participants in breast cancer, but their precise roles in cancer etiology and progression remain unclear. MMP13 helps regulate collagen structure and has been ascribed largely harmful roles in cancer, but some studies demonstrate that MMP13 may also protect against tumor pathology. Other studies indicate that collagen’s organizational patterns at the breast tumor-host interface influence metastatic potential. Therefore we investigated how MMP13 modulates collagen I, a principal collagen subtype in breast tissue, and affects tumor pathology and metastasis in a mouse model of breast cancer. Tumors were implanted into murine mammary tissues, and their growth analyzed in Wildtype and MMP13 KO mice. Following extraction, tumors were analyzed for collagen I levels and collagen I macro- and micro-structural properties at the tumor-host boundary using immunocytochemistry and two-photon and second harmonic generation microscopy. Lungs were analyzed for metastases counts, to correlate collagen I changes with a clinically significant functional parameter. Statistical analyses were performed by t-test, analysis of variance, or Wilcoxon-Mann–Whitney tests as appropriate. We found that genetic ablation of host stromal MMP13 led to: 1. Increased mammary tumor collagen I content, 2. Marked changes in collagen I spatial organization, and 3. Altered collagen I microstructure at the tumor-host boundary, as well as 4. Increased metastasis from the primary mammary tumor to lungs. These results implicate host MMP13 as a key regulator of collagen I structure and metastasis in mammary tumors, thus making it an attractive potential therapeutic target by which we might alter metastatic potential, one of the chief determinants of clinical outcome in breast cancer. In addition to identifying stromal MMP13 is an important regulator of the tumor microenvironment and metastasis, these results also suggest that stromal MMP13 may protect against

  19. Thermal requirements of Trichogramma pretiosum and T. acacioi (Hym.: Trichogrammatidae, parasitoids of the avocado defoliator Nipteria panacea (Lep.: Geometridae, in eggs of two alternative hosts

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    2005-07-01

    Full Text Available This research studied the thermal requirements of Trichogramma pretiosum and T. acacioi (Hymenoptera: Trichogrammatidae, parasitoids of Nipteria panacea (Lepidoptera: Geometridae, with eggs of the alternative hosts Anagasta kuehniella (Lepidoptera: Pyralidae and Sitotroga cerealella (Lepidoptera: Gelechiidae aiming to use these natural enemies in biological control programs of this pest in avocado orchards. T. pretiosum needed 151.83 and 160.04 degree-days, above threshold of 10.70 and 10.75°C, while these values were 158.50 and 155.46 degree-days, above threshold of 10.67 and 10.46°C for T. acacioi when exposed to eggs of A. kuehniella and S. cerealella, respectively.O objetivo desta pesquisa foi estudar as exigências térmicas de Trichogramma pretiosum e T. acacioi (Hymenoptera: Trichogrammatidae, parasitóides de Nipteria panacea (Lepidoptera: Geometridae, em ovos dos hospedeiros alternativos Anagasta kuehniella (Lepidoptera: Pyralidae e Sitotroga cerealella (Lepidoptera: Gelechiidae visando utilizar estes inimigos naturais em programas de controle biológico desta praga em pomares de abacate. T. pretiosum apresentou temperaturas base (Tb de 10.70 e 10.75°C e constantes térmicas (K de 151.83 e 160.04 graus-dia, sendo estes valores de 10.67 e 10.46°C e 158.50 e 155.46 graus-dia para T. acacioi em ovos de A. kuehniella e S. cerealella, respectivamente.

  20. An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms. Annual progress report, September 15, 1996 - September 14, 1997

    International Nuclear Information System (INIS)

    'Objectives of this project are to: (1) investigate the glass composition and processing conditions that yield optimum properties for iron phosphate glasses for vitrifying radioactive waste, (2) determine the atomic structure of iron phosphate glasses and the structure-property relationships, (3) determine how the physical and structural properties of iron phosphate glasses are affected by the addition of simulated high level nuclear waste components, and (4) investigate the process and products of devitrification of iron phosphate waste forms. The glass forming ability of about 125 iron phosphate melts has been investigated in different oxidizing to reducing atmospheres using various iron oxide raw materials such as Fe2O3, FeO, Fe3O4, and FeC2O4 2H2O. The chemical durability, redox equilibria between Fe(II) and Fe(III), crystallization behavior and structural features for these glasses and their crystalline forms have been investigated using a variety of techniques including Mossbauer spectroscopy, X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), Extended x-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) analysis, differential thermal and thermogravimetric analysis (DTA/TGA), and X-ray and neutron diffraction.'

  1. Efecto de la Infección de Spongospora subterranea f. sp. subterranea en Hospederos Alternos / Effect of Spongospora subterranea f. sp. subterranea Infection on Alternate Hosts

    Directory of Open Access Journals (Sweden)

    Ivón Magaly Arcila Aristizábal

    2014-06-01

    Full Text Available Resumen. Como una de las posibles medidas de manejo deaplicación práctica para la reducción de inóculo de Spongospora subterranea f. sp. subterranea en suelos infestados con quistosoros del patógeno, se evaluó la incidencia de su infección en diferentes plantas hospederas durante tres siembras consecutivas. Las siembras se realizaron en macetas que contenían 2 kg de suelo previamente inoculados con una concentración de 1x105quistosoros.g-1 de suelo; las cosechas de las plantas se realizaron cada tres meses, seleccionando dos muestras de raíz por maceta, una para observación de estructuras del patógeno por microscopía de luz, previa tinción con azul de tripano al 0,05% y otra para detección molecular mediante PCR en tiempo real (qPCR. Para el análisis estadístico se evaluaron los modelos Exponencial y Monomolecular, con el objetivo de seleccionar el que mejor se ajustara a los datos obtenidos. Según el valor estimado para la incidencia de estructuras del patógeno en las raíces, en las especiesCyphomandra betacea, Physalis peruvianum, Solanumnigrum, Allium cepa, Solanum quitoense y Rumex crispus,se reduce la presencia de quistosoros y zoosporangios después de tres siembras consecutivas en condiciones de casa de malla, mientras que en las especies Petroselinum crispum, Pennisetum clandestinum, Zea mays y Solanum lycopersicum se aumenta la incidencia de estructuras de S. subterranea f. sp. subterranea en las raíces. / Abstract. Trap crops have been considered an alternative strategy to reduce the inoculum of soil pathogens such as Spongospora subterranea f.sp. subterranea. In this work, the incidence of this pathogen was evaluated at three consecutive sowings using different alternative hosts. Plants were sown in pots containing 2 kg of soil inoculated with 1x105 cystosori per gram and harvested every three months. Roots were tested for the presence of cystosori and zoosporangia using light microscopy

  2. Synthesis of diluted magnetic semiconductor Bi{sub 2−x}Mn{sub x}Te{sub 3} nanocrystals in a host glass matrix

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.S. [Instituto de Ciências Exatas, Naturais e Educação (ICENE), Departamento de Física, Universidade Federal do Triângulo Mineiro, 38025-180 Uberaba, Minas Gerais (Brazil); Mikhail, H.D., E-mail: ricardosilva@fisica.uftm.edu.br [Instituto de Ciências Tecnológicas e Exatas (ICTE), Departamento de Engenharia Mecânica, Universidade Federal do Triângulo Mineiro, 38064-200 Uberaba, Minas Gerais (Brazil); Pavani, R. [Instituto de Ciências Exatas, Naturais e Educação (ICENE), Departamento de Física, Universidade Federal do Triângulo Mineiro, 38025-180 Uberaba, Minas Gerais (Brazil); Cano, N.F. [Departamento de Ciências do Mar, Universidade Federal de São Paulo, 11030-400 Santos, São Paulo (Brazil); Silva, A.C.A.; Dantas, N.O. [Instituto de Física, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Universidade Federal de Uberlândia, 38400-902 Uberlândia, Minas Gerais (Brazil)

    2015-11-05

    Diluted magnetic semiconductors of manganese doped in bismuth-telluride nanocrystals (Bi{sub 2−x}Mn{sub x}Te{sub 3} NCs) were grown in a glass matrix and investigated by Transmission Electron Microscopy, X-Ray Diffraction, Atomic Force Microscopy/Magnetic Force Microscopy, and Electron Paramagnetic Resonance. TEM images showed that the nanocrystals formed within the glass matrix were nearly spherical, with average sizes between 4 and 5 nm, and d{sub 015}-spacing of approximately 0.322 nm, which corresponds to the (015) interplanar distance in Bi{sub 2}Te{sub 3} bulk. The diffraction patterns showed that the diffraction peak associated with the (015) plane of the Bi{sub 2−x}Mn{sub x}Te{sub 3} nanocrystals shifts to larger diffraction angles as manganese (Mn) concentration increases, suggesting that the Mn{sup 2+} ions are substitutional defects occupying Bi sites (Mn{sub Bi}). AFM and MFM measurements showed magnetic phase contrast patterns, providing further evidence of Mn{sup 2+} ion incorporation in the nanocrystal structure. EPR signal of manganese ion incorporation and valence states in the crystalline structure of the Bi{sub 2}Te{sub 3} nanocrystals confirmed the presence of the Mn{sup 2+} state. - Highlights: • Bi{sub 2−x}Mn{sub x}Te{sub 3} NCs were synthesized in a glass matrix by fusion method. • Transmission Electronic Microscopy shows the formation of Bi{sub 2−x}Mn{sub x}Te{sub 3} NCs. • The sp-d exchange interaction in DMS NCs can be evidenced by X Ray-Diffraction and Magnetic Force Microscopy. • Electron Paramagnetic Resonance spectra confirmed that Mn{sup 2+} ions are located in two distinct Bi{sub 2}Te{sub 3} NCs sites.

  3. Overview of alternative sources in the Brazilian electric matrix: incentive policies, the current market and future prospects; Panorama das fontes alternativas na matriz eletrica brasileira: politicas de incentivo, mercado atual e perspectivas futuras

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Larissa Goncalves; Dedecca, Joao Gorestein; Jannuzzi, Gilberto de Martinno [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica; Gomes, Rodolfo Dourado [International Energy Initiative (IEI), Campinas, SP (Brazil)

    2010-07-01

    The Brazilian power matrix is among the cleanest in the world due to the large share of hydroelectric generation. In recent years, several efforts have been concentrated in an attempt to diversify the matrix from the insertion of other renewable alternatives sources. The aim of this study is to analyze the state of generation through biomass, wind and small hydropower sources, covered by specific auctions and the Proinfa, and solar energy (photovoltaic and thermal high temperature) in Brazil, besides trends development of these generation sources. (author)

  4. Experimental study of kinetic and mechanism of dissolution of apatite structured minerals. Application to the prediction of the long term behavior of an actinides storage host matrix

    International Nuclear Information System (INIS)

    The motivation for this study is to assess the potential of using apatite structured ceramics as long-lived actinide storage hosts. To assess their ability to resist aqueous corrosion, the dissolution of natural fluoro-apatite and synthetic Nd-britholite (neodymium is a proxy for the trivalent actinides) was studied. Mineral surfaces were characterized using a combined spectrometric, electrokinetic and potentiometric approach and dissolution rates were measured in closed and open system reactors as a function of solution composition. Experimental results suggest apatitic minerals dissolve via distinct step sequence: 1) fluoride release, 2) release of the calcium situated in the M1, and 3) the simultaneous removal of phosphate and calcium II via the breaking of only Ca-O bonds. TST based rate equations based in this mechanism accurately describe fluoro-apatite and synthetic britholite dissolution rates as a function of solution composition. Nd release rates are limited by precipitation of Nd-rhabdophane. (author)

  5. Single amino acid changes in the 6K1-CI region can promote the alternative adaptation of Prunus- and Nicotiana-propagated Plum pox virus C isolates to either host.

    Science.gov (United States)

    Calvo, María; Malinowski, Tadeusz; García, Juan Antonio

    2014-02-01

    Plum pox virus (PPV) C is one of the less common PPV strains and specifically infects cherry trees in nature. Making use of two PPV-C isolates that display different pathogenicity features, i.e., SwCMp, which had been adapted to Nicotiana species, and BY101, which had been isolated from cherry rootstock L2 (Prunus lannesiana) and propagated only in cherry species, we have generated two infective full-length cDNA clones in order to determine which viral factors are involved in the adaptation to each host. According to our results, the C-P3(PIPO)/6K1/N-CI (cylindrical inclusion) region contains overlapping but not coincident viral determinants involved in symptoms development, local viral amplification, and systemic movement capacity. Amino acid changes in this region promoting the adaptation to N. benthamiana or P. avium have trade-off effects in the alternative host. In both cases, adaptation can be achieved through single amino acid changes in the NIapro protease recognition motif between 6K1 and CI or in nearby sequences. Thus, we hypothesize that the potyvirus polyprotein processing could depend on specific host factors and the adaptation of PPV-C isolates to particular hosts relies on a fine regulation of the proteolytic cleavage of the 6K1-CI junction. PMID:24200075

  6. Role of the Emp Pilus Subunits of Enterococcus faecium in Biofilm Formation, Adherence to Host Extracellular Matrix Components, and Experimental Infection.

    Science.gov (United States)

    Montealegre, Maria Camila; Singh, Kavindra V; Somarajan, Sudha R; Yadav, Puja; Chang, Chungyu; Spencer, Robert; Sillanpää, Jouko; Ton-That, Hung; Murray, Barbara E

    2016-05-01

    Enterococcus faecium is an important cause of hospital-associated infections, including urinary tract infections (UTIs), bacteremia, and infective endocarditis. Pili have been shown to play a role in the pathogenesis of Gram-positive bacteria, including E. faecium We previously demonstrated that a nonpiliated ΔempABC::cat derivative of E. faecium TX82 was attenuated in biofilm formation and in a UTI model. Here, we studied the contributions of the individual pilus subunits EmpA, EmpB, and EmpC to pilus architecture, biofilm formation, adherence to extracellular matrix (ECM) proteins, and infection. We identified EmpA as the tip of the pili and found that deletion of empA reduced biofilm formation to the same level as deletion of the empABC operon, a phenotype that was restored by reconstituting in situ the empA gene. Deletion of empB also caused a reduction in biofilm, while EmpC was found to be dispensable. Significant reductions in adherence to fibrinogen and collagen type I were observed with deletion of empA and empB, while deletion of empC had no adherence defect. Furthermore, we showed that each deletion mutant was significantly attenuated in comparison to the isogenic parental strain, TX82, in a mixed-inoculum UTI model (P infective endocarditis model (P = 0.0088). Our results indicate that EmpA and EmpB, but not EmpC, contribute to biofilm and adherence to ECM proteins; however, all the Emp pilins are important for E. faecium to cause infection in the urinary tract. PMID:26930703

  7. The biomechanical behavior and host response to porcine-derived small intestine submucosa, pericardium and dermal matrix acellular grafts in a rat abdominal defect model.

    Science.gov (United States)

    Zhang, Jian; Wang, Guan Yu; Xiao, Yi Pin; Fan, Lie Ying; Wang, Qiang

    2011-10-01

    Several porcine-derived acellular biologic grafts are increasingly used in abdominal wall reconstruction due to the limitations of synthetic meshes in many clinical situations. However, relatively little is known so far about their comparative mechanical characteristics and performance after defect repair. We therefore investigated three most commonly used porcine-derived acellular biomaterials, small intestine submucosa (P-SIS), pericardium (P-PC) and acellular dermal matrix (P-ADM) immediately after prepared, and their effectiveness, biomechanical and histological characteristics in repairing full-thickness abdominal defect in a rat model. P-PC had the best native performance in the burst strength, tensile strength and ball burst among the three porcine-derived scaffolds. P-SIS showed a significantly higher water vapor transmission in comparison with P-PC or P-ADM. Abdominal wall defects in rats were all satisfied repaired with P-SIS, P-PC or P-ADM. No laxity or fistula was observed in the repaired abdominal wall in the P-SIS group up to 8 weeks after surgery. However, there was a tendency for high postoperative abdominal eventration in the P-ADM and P-PC groups as compared with the P-SIS group. With regard to overall aspects of the postoperative laxity, intra-abdominal adhesion formation, tensile stress, stretchability, and degree of tissue ingrowth in terms of collagen deposition and neovascularization, P-SIS exhibits clear advantages over P-PC as well as P-ADM after large abdominal wall defect reconstruction. PMID:21741703

  8. HostPhinder: A Phage Host Prediction Tool

    OpenAIRE

    Julia Villarroel; Kortine Annina Kleinheinz; Vanessa Isabell Jurtz; Henrike Zschach; Ole Lund; Morten Nielsen; Mette Voldby Larsen

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPh...

  9. Host Responses to Biofilm.

    Science.gov (United States)

    Watters, C; Fleming, D; Bishop, D; Rumbaugh, K P

    2016-01-01

    From birth to death the human host immune system interacts with bacterial cells. Biofilms are communities of microbes embedded in matrices composed of extracellular polymeric substance (EPS), and have been implicated in both the healthy microbiome and disease states. The immune system recognizes many different bacterial patterns, molecules, and antigens, but these components can be camouflaged in the biofilm mode of growth. Instead, immune cells come into contact with components of the EPS matrix, a diverse, hydrated mixture of extracellular DNA (bacterial and host), proteins, polysaccharides, and lipids. As bacterial cells transition from planktonic to biofilm-associated they produce small molecules, which can increase inflammation, induce cell death, and even cause necrosis. To survive, invading bacteria must overcome the epithelial barrier, host microbiome, complement, and a variety of leukocytes. If bacteria can evade these initial cell populations they have an increased chance at surviving and causing ongoing disease in the host. Planktonic cells are readily cleared, but biofilms reduce the effectiveness of both polymorphonuclear neutrophils and macrophages. In addition, in the presence of these cells, biofilm formation is actively enhanced, and components of host immune cells are assimilated into the EPS matrix. While pathogenic biofilms contribute to states of chronic inflammation, probiotic Lactobacillus biofilms cause a negligible immune response and, in states of inflammation, exhibit robust antiinflammatory properties. These probiotic biofilms colonize and protect the gut and vagina, and have been implicated in improved healing of damaged skin. Overall, biofilms stimulate a unique immune response that we are only beginning to understand. PMID:27571696

  10. An alternative improved method for the homogeneous dispersion of CNTs in Cu matrix for the fabrication of Cu/CNTs composites

    Science.gov (United States)

    Lal, Maneet; Singhal, S. K.; Sharma, Indu; Mathur, R. B.

    2013-02-01

    Copper has a wide range of applications due to its excellent properties (high thermal and electrical conductivity). Carbon nanotubes (CNTs) are widely used as a reinforcing material due to their superior properties. Copper/Carbon nanotube (Cu/CNTs) composites show enhanced mechanical, electrical and thermal properties as compared to pure Cu and Cu composites. Hence, Cu/CNTs composites have tremendous applications. Cu/CNTs are being developed for use as antifungal and antimicrobial agents, which can lead to their further use in biomedical devices and implant materials. The versatility of this material is such that Cu/CNTs are being developed for use in ultra-large scale integrated circuits for use in the latest integrated circuits and semiconductor chips. The composite material is being used as heat sinks for various industries. Cu/CNTs are now also being employed as catalysts for various industrial reactions. Fuel cell electrodes based on Cu/CNTs are being developed to replace expensive Pt/Pd-based electrodes, currently being used. Another application in the energy sector is the use of Cu/CNTs in direct methanol fuel cells and in methanol gas reforming for H2 production. These extensive applications provided motivation for the current work. However, these applications can only be realized if a stable and uniform Cu/CNTs composite powder can be made. The challenges in fabricating Cu/CNTs composites are: (1) homogeneous dispersion of CNTs in Cu matrix, (2) interfacial bonding between CNTs and Cu matrix and (3) retention of structural integrity of CNTs. Powder metallurgy (PM) has been widely used, but dispersion of Cu/CNTs remains an issue. We employed the molecular level mixing method (MLM), coupled with high energy ball milling (BM) to overcome above mentioned issues. To the best of our knowledge, this is a new process for the homogeneous dispersion of CNTs in copper and has been reported for the first time. To produce a homogenous mixture of Cu and CNTs, a

  11. Dense Alternating Sign Matrices and Extensions

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Hall, F.J.; Stroev, M.

    2014-01-01

    Roč. 444, 1 March (2014), s. 219-226. ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : alternating sign matrix * dense matrix * totally unimodular matrix * combined matrix * generalized complementary basic matrix Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014

  12. HostPhinder: A Phage Host Prediction Tool.

    Science.gov (United States)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell; Zschach, Henrike; Lund, Ole; Nielsen, Morten; Larsen, Mette Voldby

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k) is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2]. PMID:27153081

  13. Electric energy generation matrix alternatives for the expansion of the Brazil 2000 - 2030 - 2050 electric power offer; Alternativas de matrizes de geracao de energia eletrica para expansao da oferta de eletricidade Brasil 2000 - 2030 - 2050

    Energy Technology Data Exchange (ETDEWEB)

    Bahia, Raymundo Ruy; Silva, Marcos Vinicius M. da; Luczynski, Estanislau [Universidade da Amazonia (UNAMA), Manaus, AM (Brazil). Grupo de Pesquisas Economicas Energeticas]. E-mails: ruybahia@uol.com.br; vini67@ig.com.br; stasnis@yahoo.com

    2006-07-01

    This paper is a follow-up of several papers presented by the authors in the 9. CBE (2002), 4. CBPE (2004) and X CBE (2004) congresses. These papers discussed some tools for energy planning aiming to develop some alternatives of Brazilian electricity generation matrices. Data used for such follow-up led to some new forecasting based on economic scenarios, which were related to electricity generation matrices. Rates are taken from macro economic series since 1970. However, it is assumed that from 2010 to 2050 there will be a new cycle of economic growing. Such cycle varies from an average growing one to a sustainable one in opposition to the recessive cycle of 1980 to 2010. Investments required to expansion of electrical generation installed capacity were obtained by an evaluation of generation and energy transmission costs, which were based on analysing some options to generation matrices that are hydropower, hydro thermo and thermo hydro ones. These matrices were forecasted for two periods, the first one from 2000 to 2030 and the second one from 2030 to 2050. Such analysing reveals that the hydropower generation is uneconomic, even when it is considered as an alternative for expansion of electricity supplying. Such uneconomic conditions are perennial and they are even worst since the Brazilian electricity power rationing of 2001. Hydro thermo and thermo hydro matrices have a lot of financial, economical and ecological advantages when they are compared to hydropower one in any scenario whether high or low ones, both of them considered for the period of 2000 to 2050. Data analyses showed here may be considered as a study, which can help discussions and evaluations of energy planning governmental offices by making them to understand that hydropower matrix is out of date, and it is not an economic option to be used in a supply expansion plan for the considered periods of 2000 to 2030 and 2030 to 2050. (author)

  14. Channel matrix, measurement matrix and collapsed matrix in teleportation

    OpenAIRE

    Zha, Xin-Wei; Qi, Jian-Xia; Song, Hai-Yang

    2014-01-01

    In this paper, two kinds of coefficient matrixes (channel matrix, measurement matrix)associated with the pure state for teleportation are presented, the general relation among channel matrix, measurement matrix and collapsed matrix is obtained. In addition, a criterion for teleportation that the number of coefficient of an unknown state is determined by the rank of the collapsed matrix is given.

  15. The matrix theory S matrix

    OpenAIRE

    Plefka, J. C.; Serone, M.; Waldron, A.K.

    1998-01-01

    The technology required for eikonal scattering amplitude calculations in Matrix theory is developed. Using the entire supersymmetric completion of the v^4/r^7 Matrix theory potential we compute the graviton-graviton scattering amplitude and find agreement with eleven dimensional supergravity at tree level.

  16. Matrix calculus

    CERN Document Server

    Bodewig, E

    1959-01-01

    Matrix Calculus, Second Revised and Enlarged Edition focuses on systematic calculation with the building blocks of a matrix and rows and columns, shunning the use of individual elements. The publication first offers information on vectors, matrices, further applications, measures of the magnitude of a matrix, and forms. The text then examines eigenvalues and exact solutions, including the characteristic equation, eigenrows, extremum properties of the eigenvalues, bounds for the eigenvalues, elementary divisors, and bounds for the determinant. The text ponders on approximate solutions, as well

  17. Alternation of host plants as a survival mechanism of leafhoppers Dilobopterus costalimai and Oncometopia facialis (Hemiptera: Cicadellidae, vectors of the Citrus Variegated Chlorosis (CVC Alternância de hospedeiros como mecanismo de sobrevivência das cigarrinhas Dilobopterus costalimai e Oncometopia facialis (Hemiptera: Cicadellidae, vetoras da Clorose Variegada dos Citros (CVC

    Directory of Open Access Journals (Sweden)

    José Maria Milanez

    2001-12-01

    Full Text Available Dilobopterus costalimai (Young and Oncometopia facialis (Signoret are two of the most important species of citrus leafhoppers, vectors of bacterium Xylella fastidiosa which causes the Citrus Variegated Chlorosis (CVC disease. To develop a rearing technique for these species under laboratory conditions, the egg laying preference and nymph development were studied in different breeding systems: Rangpur lime (Citrus limonia and "falso boldo" (Vernonia condensata as host plants. Trials were set up in a randomized block design with three treatments (n=8. Females of D. costalimai had particular preference for ovipositing on Rangpur lime leaves while O. facialis females placed a higher number of eggs on "falso boldo", but it did not differ statistically from the Rangpur lime. The nymphal viability of D. costalimai was null in Rangpur lime and 58% in "falso boldo". For O. facialis the nymphal viability was 25 and 78% in Rangpur lime and "falso boldo", respectively. "Falso boldo" is more suitable as a host plant to rear the two species of citrus leafhoppers. The alternation of host plants seems to be an important survival mechanism of the CVC-vector species, as shown in natural conditions.Dilobopterus costalimai (Young e Oncometopia facialis (Signoret são duas das mais importantes espécies de cigarrinhas dos citros, transmissoras da bactéria Xylella fastidiosa causadora da doença conhecida como Clorose Variegada dos Citros (CVC. Com o objetivo de se desenvolver uma técnica de criação destas espécies, em condições de laboratório, estudou-se a preferência por postura e o desenvolvimento ninfal, em diferentes sistemas de criação, tendo como plantas hospedeiras limão cravo (Citrus limonia e falso boldo (Vernonia condensata. O delineamento experimental foi em blocos casualizados com três tratamentos e oito repetições. Fêmeas de D. costalimai tiveram acentuada preferência para ovipositar em folhas de limão cravo, enquanto que fêmeas de O

  18. Matriz informatizada de principios básicos de seguridad: una alternativa útil para su aprendizaje y aplicación // Computerized matrix of safety basic principles: a useful alternative for their learning and application

    Directory of Open Access Journals (Sweden)

    Antonio Torres-Valle

    2011-08-01

    Full Text Available ResumenEl artículo presenta un resumen general de las características distintivas de varios métodos deanálisis de seguridad. Partiendo de las limitaciones intrínsecas de los mismos para realizarevaluaciones integrales de los principios de seguridad, se propone un método de fácil manejo pararealizar análisis cualitativos de seguridad, dirigido además a sistematizar el uso de los PrincipiosBásicos de Seguridad (PBS. Esta alternativa tiene como objetivo primordial promover el aprendizajede los PBS. Las bases metodológicas del método propuesto son, una matriz interdependiente dePBS y un sistema de seguimiento de configuraciones peligrosas que enlaza los sistemastecnológicos de la instalación y/o las características gerenciales de la entidad estudiada, con los PBScorrespondientes. El artículo muestra el uso del código utilizando como referencia una instalaciónsimplificada.Palabras claves: seguridad, principios, métodos, evaluación, configuración, control.___________________________________________________________________________AbstractThe paper presents an abstract of the distinctive characteristics of various methods of safety analysis.Beginning from the inherent limitations of these methods for the integral assessments of the safetyprinciples, is proposed an easy-to-manage method for qualitative safety analysis, which as additionalcapability can be used to interpret and apply the Basic Safety Principles (BSP. The principalobjective of this alternative is the BSP learning promotion. The methodological bases of the proposedmethod are the interdependent matrix of BSP and the system to trace dangerous configurations thatcoupled the technological systems of the facility and/or the management characteristics of the studiedentity with the respective BSP. The paper shows the use of the computer code using as reference asimplified facility.Key words: safety, principles, methods, assessment, configuration, control

  19. Alternative security

    International Nuclear Information System (INIS)

    This book contains the following chapters: The Military and Alternative Security: New Missions for Stable Conventional Security; Technology and Alternative Security: A Cherished Myth Expires; Law and Alternative Security: Toward a Just World Peace; Politics and Alternative Security: Toward a More Democratic, Therefore More Peaceful, World; Economics and Alternative Security: Toward a Peacekeeping International Economy; Psychology and Alternative Security: Needs, Perceptions, and Misperceptions; Religion and Alternative Security: A Prophetic Vision; and Toward Post-Nuclear Global Security: An Overview

  20. Survival and larval development of Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) on alternatives host; Sobrevivencia e desenvolvimento larval de Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) em hospedeiros alternativos

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Verissimo G.M. de [Universidade Federal de Minas Gerais (UFMG), Montes Claros, MG (Brazil). Dept. de Agronomia; Fonseca, Bernardo V.C. [Universidade FUMEC, Belo Horizonte, MG (Brazil); Boregas, Katia G.B. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Ecologia; Waquil, Jose M. [EMBRAPA Milho e Sorgo, Sete Lagoas, MG (Brazil)]. E-mail: aaquil@cnpms.embrapa.br

    2009-01-15

    Two bioassays were conducted to evaluate the suitability of host plants of fall armyworm (FAW), Spodoptera frugiperda (J E Smith), in the Brazilian agro-ecosystem. Larval development and survival were analyzed by infesting leaves of maize, grain sorghum, Johnson grass, soybean, Brachiaria and tobacco with FAW newly hatched larvae in a no choice test. No significant differences of survival were observed among insects reared on different hosts, except for tobacco, where no survivors were recorded. Larvae fed on soybean and artificial diet grew larger than those fed on the other hosts. The heaviest pupa was observed from larva fed on artificial diet and the lighter from larva fed on Brachiaria grass. No significant differences were reported on larval development time on natural hosts, but it was longer for larvae reared on artificial diet. Three classes of larval development time were observed on maize, four on sorghum, Brachiaria and soybean, and five on artificial diet. Nearly 85% of FAW larvae completed development within 12 d on maize; 77% on grain sorghum, 80% on Johnson grass, 68% on Brachiaria and 83% on soybean within 14 d and 69% on artificial diet within 17 d. The host suitability to FAW decreases from maize to sorghum, soybean and Brachiaria. (author)

  1. Additive rank preservers on n × n alternate matrix spaces over fields:the case that n is even%域上偶数阶交错矩阵空间的加法秩保持

    Institute of Scientific and Technical Information of China (English)

    张显; 袁晖坪

    2005-01-01

    Let Kn (F) be the linear space of all n × n alternate matrices over a field F. An operator f:Kn(F)→Kn(F) is called an additive preserver of rank on Kn(F) iff(A +B) =f(A) +f(B) for all A,B ∈ Kn (F) and rank f(X) = rankX for every X ∈ Kn(F). It is shown that, assuming that n is even with n ≥4 and F is arbitrary, f is an additive preserver of rank on Kn (F) if, and only if, there exist a nonzero scalar γ, a nonsingular n × n matrix P and an injective field endomorphism δ of F such that either f: [aij]|→αP [aδij]PT, or n = 4 and f: [ aij ] |→αP ★ ( [aδij] ) pT, where ★: K4 ( F ) →K4 (F) denotes the operator exchanging the (1,4) -th entry with the (2,3) -th entry and the (4,1) -th entry with the (3,2) -th entry.%设Kn(F)是域F上所有n×n交错矩阵构成的线性空间.如果一个算子f:Kn(F)→Kn(F)满足对所有的A,B∈Kn(F)有f(A+B)=f(A)+f(B)并且对任意的X∈Kn(F)有rank f(X)=rank X,则称f是Kn(F)上的加法秩保持.当n是不小于4的整数且F任意时,证明了f是Kn(F)上的加法秩保持当且仅当存在非零的纯量γ、非奇异的n×n矩阵P和域F的单自同态δ满足或者f:[aij]|→αP[aδij]PT,或者n=4且f:[aij]|→αP★([aδij)PT,其中★:K4(F)→K4(F)表示对换(1,4)和(2,3)位置元素及(4,1)和(3,2)位置元素的算子.

  2. Cost of host radiation in an RNA virus.

    OpenAIRE

    Turner, P E; Elena, S.F.

    2000-01-01

    Although host radiation allows a parasite to expand its ecological niche, traits governing the infection of multiple host types can decrease fitness in the original or alternate host environments. Reasons for this reduction in fitness include slower replication due to added genetic material or modifications, fitness trade-offs across host environments, and weaker selection resulting from simultaneous adaptation to multiple habitats. We examined the consequences of host radiation using vesicul...

  3. Knot theory and matrix integrals

    CERN Document Server

    Zinn-Justin, P

    2010-01-01

    The large size limit of matrix integrals with quartic potential may be used to count alternating links and tangles. The removal of redundancies amounts to renormalizations of the potential. This extends into two directions: higher genus and the counting of "virtual" links and tangles; and the counting of "coloured" alternating links and tangles. We discuss the asymptotic behavior of the number of tangles as the number of crossings goes to infinity.

  4. The Reciprocal Pascal Matrix

    OpenAIRE

    Richardson, Thomas M.

    2014-01-01

    The reciprocal Pascal matrix is the Hadamard inverse of the symmetric Pascal matrix. We show that the ordinary matrix inverse of the reciprocal Pascal matrix has integer elements. The proof uses two factorizations of the matrix of super Catalan numbers.

  5. Host Selection of Microbiota via Differential Adhesion.

    Science.gov (United States)

    McLoughlin, Kirstie; Schluter, Jonas; Rakoff-Nahoum, Seth; Smith, Adrian L; Foster, Kevin R

    2016-04-13

    The host epithelium is the critical interface with microbial communities, but the mechanisms by which the host regulates these communities are poorly understood. Here we develop the hypothesis that hosts use differential adhesion to select for and against particular members of their microbiota. We use an established computational, individual-based model to study the impact of host factors that regulate adhesion at the epithelial surface. Our simulations predict that host-mediated adhesion can increase the competitive advantage of microbes and create ecological refugia for slow-growing species. We show how positive selection via adhesion can be transformed into negative selection if the host secretes large quantities of a matrix such as mucus. Our work predicts that adhesion is a powerful mechanism for both positive and negative selection within the microbiota. We discuss molecules-mucus glycans and IgA-that affect microbe adhesion and identify testable predictions of the adhesion-as-selection model. PMID:27053168

  6. Alternate hosts of spongospora subterranea f. sp. subterranea identification in colombia by bioassay / identificación de hospederos alternos de spongospora subterranea f. sp. subterranea en colombia por bioensayos

    OpenAIRE

    Ivon Magaly Arcila Aristizabal; Elena Paola González Jaimes; Catalina María Zuluaga Amaya; José Miguel Cotes Torres

    2013-01-01

    Potato powdery scab, caused by Spongosporasubterranea f. sp. subterranea, is a disease that limits worldwide potato crop production. Incidence of the disease has been increasing in Colombia, thereby affecting tubers production, so far effective control methods have yet to be developed. The aim of this research was to establish the host range plants for Spongospora subterranea f. sp. subterranea by artificial inoculations. Thus, 33 species were inoculated with 1×106 sporosori.mL-1 solution for...

  7. Host plant adaptation in Drosophila mettleri populations.

    Science.gov (United States)

    Castrezana, Sergio; Bono, Jeremy M

    2012-01-01

    The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total). We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea) for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp.) in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts. PMID:22493678

  8. Host plant adaptation in Drosophila mettleri populations.

    Directory of Open Access Journals (Sweden)

    Sergio Castrezana

    Full Text Available The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total. We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp. in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts.

  9. Matrix analysis

    CERN Document Server

    Bhatia, Rajendra

    1997-01-01

    A good part of matrix theory is functional analytic in spirit. This statement can be turned around. There are many problems in operator theory, where most of the complexities and subtleties are present in the finite-dimensional case. My purpose in writing this book is to present a systematic treatment of methods that are useful in the study of such problems. This book is intended for use as a text for upper division and gradu­ ate courses. Courses based on parts of the material have been given by me at the Indian Statistical Institute and at the University of Toronto (in collaboration with Chandler Davis). The book should also be useful as a reference for research workers in linear algebra, operator theory, mathe­ matical physics and numerical analysis. A possible subtitle of this book could be Matrix Inequalities. A reader who works through the book should expect to become proficient in the art of deriving such inequalities. Other authors have compared this art to that of cutting diamonds. One first has to...

  10. Matrix pentagons

    CERN Document Server

    Belitsky, A V

    2016-01-01

    The Operator Product Expansion for null polygonal Wilson loop in planar maximally supersymmetric Yang-Mills theory runs systematically in terms of multiparticle pentagon transitions which encode the physics of excitations propagating on the color flux tube ending on the sides of the four-dimensional contour. Their dynamics was unravelled in the past several years and culminated in a complete description of pentagons as an exact function of the 't Hooft coupling. In this paper we provide a solution for the last building block in this program, the SU(4) matrix structure arising from internal symmetry indices of scalars and fermions. This is achieved by a recursive solution of the Mirror and Watson equations obeyed by the so-called singlet pentagons and fixing the form of the twisted component in their tensor decomposition. The non-singlet, or charged, pentagons are deduced from these by a limiting procedure.

  11. Candida Biofilms and the Host: Models and New Concepts for Eradication

    Directory of Open Access Journals (Sweden)

    Hélène Tournu

    2012-01-01

    Full Text Available Biofilms define mono- or multispecies communities embedded in a self-produced protective matrix, which is strongly attached to surfaces. They often are considered a general threat not only in industry but also in medicine. They constitute a permanent source of contamination, and they can disturb the proper usage of the material onto which they develop. This paper relates to some of the most recent approaches that have been elaborated to eradicate Candida biofilms, based on the vast effort put in ever-improving models of biofilm formation in vitro and in vivo, including novel flow systems, high-throughput techniques and mucosal models. Mixed biofilms, sustaining antagonist or beneficial cooperation between species, and their interplay with the host immune system are also prevalent topics. Alternative strategies against biofilms include the lock therapy and immunotherapy approaches, and material coating and improvements. The host-biofilm interactions are also discussed, together with their potential applications in Candida biofilm elimination.

  12. Impact of energy efficiency and alternative sources in the Brazilian electric matrix: scenarios 2005-2050; Impacto da eficiencia energetica e das fontes alternativas na matriz eletrica brasileira: cenarios 2005-2050

    Energy Technology Data Exchange (ETDEWEB)

    Saidel, Marco A.; Gimenes, Andre L.V.; Fujii, Ricardo J. [Universidade de Sao Paulo (GEPEA/USP), SP (Brazil). Dept. de Energia e Automacao Eletricas. Grupo de Energia; Furtado, Marcelo [Greenpeace Brasil, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Part of a worldwide initiative championed by Greenpeace International and EREC - European Renewable Energy Council, a partnership between Greenpeace Brazil and GEPEA/USP were established for producing two national alternative energy scenarios, as a blueprint for how to meet forthcoming Brazilian energy needs in a sustainable way. Such scenarios, one reflecting the views of GEPEA/USP and another the perceptions by Greenpeace, were both based on a reference scenario strongly drawing from the 'Plano Decenal 2006-2015' and the 'Plano Nacional de Energia 2030', both by the Ministry of Mines and Energy. From the alternative scenarios one may see that is feasible to satisfy the increasing Brazilian demand through the integrated deployment of alternative resources, Natural Gas fueled thermal power plants and energy conservation measures. To develop the Brazilian electricity energy base in such terms, however, is mandatory to conduct further debate on energy planning issues, conservation measures and alternatives resources concerns included. (author)

  13. BUTYRATE-MEDIATED GENOMIC CHANGES INVOLVED IN NON-SPECIFIC HOST DEFENSES, MATRIX REMODELING AND THE IMMUNE RESPONSE IN THE RUMEN EPITHELIUM OF COWS AFFLICTED WITH SUBACUTE RUMINAL ACIDOSIS

    Directory of Open Access Journals (Sweden)

    Louis Dionissopoulos

    2013-01-01

    involved in Non-Specific Host Defense (NSHD, Remodeling or adaptation (RM and Immune Response (IR. Of the 49 genes tested by qRT-PCR, 9 (LCN2, MMP1, MUC16, GPX2, CSTA, FUT1, SERPINE2, BCAM, RAC3 were upregulated, 20 (MTOR, AKIRIN2, NFKBIZ, NFKB2, ACVR2A, LAMB1, FRS2, PPARD, LBP, NEDD4L, SGK1, DEDD2, MAP3K8, PARD6B, PLIN2, ADA, HPGD, FMO5, BMP6, TCHH were downregulated and 20 were unchanged due to butyrate administration in the proximal gastrointestinal tract. These results demonstrate the potential protective effect and molecular mechanisms involved in a novel butyrate treatment for inflammatory gastrointestinal conditions.

  14. Alternate Hosts of Spongospora subterranea f. sp. subterranea Identification in Colombia by Bioassay / Identificación de Hospederos Alternos de Spongospora subterranea f. sp. subterranea en Colombia por Bioensayos

    Directory of Open Access Journals (Sweden)

    Ivon Magaly Arcila Aristizabal

    2013-12-01

    Full Text Available Potato powdery scab, caused by Spongosporasubterranea f. sp. subterranea, is a disease that limits worldwide potato crop production. Incidence of the disease has been increasing in Colombia, thereby affecting tubers production, so far effective control methods have yet to be developed. The aim of this research was to establish the host range plants for Spongospora subterranea f. sp. subterranea by artificial inoculations. Thus, 33 species were inoculated with 1×106 sporosori.mL-1 solution for 12 days. The plants were then planted in field, evaluations were performed at 15, 30, 60, 90 and 120 days after inoculation, 10 plants of each species were selected for every evaluation, the rootswere stained and the pathogenic structures were identified bymicroscopy. Morphological examination enabled the identification of trap plants species, which presented zoosporangia only; Type I hosts, which present sporosori only; and Type II hosts, which presented both sporosori and zoosporangia. Some of these hosts belonged to the Alliaceae, Apiaceae, Brassicaceae, Poaceae, Polygonaceae and Solanaceae families, thus extending the speciesrange that can be reported as hosts of Spongospora subterranea f. sp. subterranea in Colombia. / El agente causal de la sarna polvosa de la papa,Spongospora subterranea f. sp. subterranea es una de lasenfermedades más limitantes de la producción del cultivo anivel mundial. En Colombia, viene incrementando su incidencia al punto de disminuir la producción, sin llegar a encontrar métodos de control efectivos. En este estudio, se buscó establecer un rango de hospederos del patógeno a partir de inoculaciones por bioensayos. Así, plantas de 33 especies se inocularon en solución a una concentración de 1x106 quistosoros mL-1 durante 12 días; posteriormente, las plantas fueron sembradas en campo, realizando evaluaciones a los 15, 30, 60, 90 y 120 días después de inoculadas. En cada evaluación se seleccionaron diez plantasde

  15. Trusted Hosts in Host Identity Protocol (HIP)

    OpenAIRE

    K.C., Amir

    2012-01-01

    The goal of the project was to study the possibilities to establish trusted hosts in Host Identity Protocol (HIP) and implement certificate handling in HIP packets. The time complexity and performance while using certificates in HIP packets was also measured. The research project was carried out at Arcada University of Applied Sciences in collaboration with Helsinki University. The project aimed to implement standard x.509 certification of the public key used as HI (Host Identity) to deri...

  16. Venturini Method Based Matrix Converter

    Directory of Open Access Journals (Sweden)

    Derick Mathew

    2015-03-01

    Full Text Available Recently, matrix converter has received considerable interest as a viable alternative to the conventional ac-dc-ac converter. This direct ac-ac converter provides some attractive characteristics such as: four quadrant operation, absence of bulky dc-link electrolyte capacitors, clean input power characteristics. Due to the absence of dc link energy storage elements any disturbance in the input voltage will be immediately reflected to the output voltages. In this paper venturini method for matrix converter has been presented. Three phase sinusoidal symmetrical voltage or current can obtained .

  17. Estádio de adaptação de Spodoptera frugiperda (J. E. Smith (Lepidoptera: Noctuidae em hospedeiros alternativos Fitness stage of Spodoptera frugiperda (J. E. Smith (Lepidoptera: Noctuidae on alternative hosts

    Directory of Open Access Journals (Sweden)

    Katia Gisele Brasil Boregas

    2013-03-01

    -de-açúcar.The main target pest on maize is the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797 (Lepidoptera: Noctuidae, which, by their seasonal and geographical distribution is one of the most damaging species in tropical regions of America. The objective was the evaluation of S. frugiperda fitness stage on 17 host plant species, cultivated or wild, most common in the Brazilian agro ecosystem. The plants were cultivated in five planting times, between 2006 and 2008, using corn as standard of comparison. Newly hatched larvae of S. frugiperda were individualized and confined in 50 mL plastic pots, where they were fed with new leaves of each host. Food was replaced every other day with fresh leaf sections of each plant host. Four biological variables were evaluated and used to estimate the Fitness Index (FI. The initial larval survival ranged from 100% on maize to 46% on rice. The larval period ranged from 12.6 days on maize to 27.1 days on bahiagrass. The pupa biomass ranged from 173.1 mg on burgrass to 294.2 mg on maize. The fitness index, calculated on the base of S. frugiperda fitness on each host ranged from 17.43 on maize cultivated at time I to 1.46 on sugarcane cultivated at time III. In order to correct the time effect on S. frugiperda fitness stage on hosts, the Relative Fitness Index (RFI was calculated in relation to maize crop. According to this index, the host rank to S. frugiperda fitness was in decreasing order: grain sorghum, johnson grass, millet, guinea grass, peanut, bread grass, surinam grass, green amaranth, wheat, soybean, cotton, bean, rice, burgrass, bahiagrass and sugarcane.

  18. Summary of laser speckle photogrammetry for HOST

    Science.gov (United States)

    Pollack, Frank G.

    1986-01-01

    High temperature static strain measurement capability is important for the success of the HOST program. As part of the NASA Lewis effort to develop the technology for improved hot-section durability, the HOST instrumentation program has, as a major goal, the development of methods for measuring strain at high temperature. Development work includes both improvements in resistance strain-gauge technology and, as an alternative approach, the development of optical techniques for high temperature strain measurement.

  19. Basic matrix algebra and transistor circuits

    CERN Document Server

    Zelinger, G

    1963-01-01

    Basic Matrix Algebra and Transistor Circuits deals with mastering the techniques of matrix algebra for application in transistors. This book attempts to unify fundamental subjects, such as matrix algebra, four-terminal network theory, transistor equivalent circuits, and pertinent design matters. Part I of this book focuses on basic matrix algebra of four-terminal networks, with descriptions of the different systems of matrices. This part also discusses both simple and complex network configurations and their associated transmission. This discussion is followed by the alternative methods of de

  20. Graphite powder as an alternative or supplement to reversed-phase material for desalting and concentration of peptide mixtures prior to matrix-assisted laser desorption/ionization-mass spectrometry

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Cordwell, Stuart J; Roepstorff, Peter

    2002-01-01

    microcolumns, or are suppressed in the ionization process. We report here the use of graphite powder packed in constricted GELoader tips as an alternative to RP microcolumns for desalting and concentration of peptide mixtures prior to MS. Such columns are able to retain small and/or hydrophilic peptides that...

  1. Chemically modified tetracyclines: The novel host modulating agents

    OpenAIRE

    Devulapalli Narasimha Swamy; Sahitya Sanivarapu; Srinivas Moogla; Vasavi Kapalavai

    2015-01-01

    Periodontal pathogens and destructive host responses are involved in the initiation and progression of periodontitis. The emergence of host response modulation as a treatment concept has resulted from our improved understanding of the pathogenesis of periodontal disease. A variety of drugs have been evaluated as host modulation agents (HMA), including Non Steroidal Anti Inflammatory Drugs (NSAIDS), bisphosphonates, tetracyclines, enamel matrix proteins and bone morphogenetic proteins. Chemica...

  2. Riemann Zeta Matrix Function

    OpenAIRE

    Kargın, Levent; Kurt, Veli

    2015-01-01

    In this study, obtaining the matrix analog of the Euler's reflection formula for the classical gamma function we expand the domain of the gamma matrix function and give a infinite product expansion of sinπxP.  Furthermore we define Riemann zeta matrix function and evaluate some other matrix integrals. We prove a functional equation for Riemann zeta matrix function.

  3. Orthogonal Matrix in Cryptography

    OpenAIRE

    Santana, Yeray Cachon

    2014-01-01

    In this work is proposed a method using orthogonal matrix transform properties to encrypt and decrypt a message. It will be showed how to use matrix functions to create complex encryptions. Because orthogonal matrix are always diagonalizable on R, and the exponential of a diagonal matrix is easy to compute, the exponential of orthogonal matrix will be used to encrypt text messages.

  4. Tick-Host Specificity

    OpenAIRE

    Hoogstraal, H.; Aeschlimann, André

    2010-01-01

    A review the various patterns of tick-host relationships are discussed in detail in order to answer the following questions : 1. How, when and where did host specificity of each parasite group evolve ? 2. How strict is specificity in each case ? 3. Why and under what circumstances does specificity break down ? The authors present several definitions which characterize the various degrees of parasitic specificity existing today between ticks and their hosts. Tick-host relationships are ...

  5. Bottom-up and top-down solid-state NMR approaches for bacterial biofilm matrix composition

    Science.gov (United States)

    Cegelski, Lynette

    2015-04-01

    The genomics and proteomics revolutions have been enormously successful in providing crucial "parts lists" for biological systems. Yet, formidable challenges exist in generating complete descriptions of how the parts function and assemble into macromolecular complexes and whole-cell assemblies. Bacterial biofilms are complex multicellular bacterial communities protected by a slime-like extracellular matrix that confers protection to environmental stress and enhances resistance to antibiotics and host defenses. As a non-crystalline, insoluble, heterogeneous assembly, the biofilm extracellular matrix poses a challenge to compositional analysis by conventional methods. In this perspective, bottom-up and top-down solid-state NMR approaches are described for defining chemical composition in complex macrosystems. The "sum-of-the-parts" bottom-up approach was introduced to examine the amyloid-integrated biofilms formed by Escherichia coli and permitted the first determination of the composition of the intact extracellular matrix from a bacterial biofilm. An alternative top-down approach was developed to define composition in Vibrio cholerae biofilms and relied on an extensive panel of NMR measurements to tease out specific carbon pools from a single sample of the intact extracellular matrix. These two approaches are widely applicable to other heterogeneous assemblies. For bacterial biofilms, quantitative parameters of matrix composition are needed to understand how biofilms are assembled, to improve the development of biofilm inhibitors, and to dissect inhibitor modes of action. Solid-state NMR approaches will also be invaluable in obtaining parameters of matrix architecture.

  6. Plantas daninhas hospedeiras alternativas de Colletotrichum guaranicola em cultivos de guaraná no Estado do Amazonas Alternative host weeds of Colletotrichum guaranicola in guarana crops in the State Amazonas

    Directory of Open Access Journals (Sweden)

    L.J. Miléo

    2007-12-01

    Full Text Available As plantas daninhas reduzem a produção de sementes de guaraná e podem hospedar microrganismos patogênicos, tornando-se potenciais fontes de inóculo. Este trabalho identificou espécies de plantas daninhas colonizadas pelo fungo Colletotrichum guaranicola em cultivos de guaranazeiro em quatro municípios do Estado do Amazonas. As plantas daninhas foram identificadas e a presença do fungo foi verificada por meio de isolamentos feitos a partir de fragmentos de folhas lesionadas. As espécies colonizadas por C. guaranicola foram Bidens bipinnata, Chloris sp., Clidemia capitellata, Cyperus flavus, Elephantopus scaber, Euphorbia brasiliensis, Hemidiodia sp., Hyptis lantanifolia, Paspalum conjugatum, Physalis angulata e Synedrella nodiflora, as quais podem representar uma fonte de inóculo do patógeno, além das plantas de guaraná. A diversidade de plantas daninhas, em cultivos de guaranazeiro, reforça a importância de estabelecer práticas de manejo dessas plantas, principalmente em Maués, onde ocorreu maior colonização das espécies de plantas daninhas pelo fungo.Weed infestation may reduce grain guarana crops yield and host plant pathogens becoming potential inoculum sources. This research identified weed species colonized by the fungus Colletotrichum guaranicola in the guarana crop in four counties in the state of Amazon. The weeds were identified fungi presence was observed by isolation from leaf fragments of leaves injured by the fungi. The weed species colonized by Colletotrichum guaranicola were Bidens bipinnata, Chloris sp., Clidemia capitellata, Cyperus flavus, Elephantopus scaber, Euphorbia brasiliensis, Hemidiodia sp., Hyptis lantanifolia, Paspalum conjugatum, Physalis angulata and Synedrella nodiflora,that may represent a strong potential of plant pathogen inoculum, along with the guarana plants. Weed diversity in guarana crop shows the importance of establishing management practices to control these weeds, mainly in the Maues

  7. Alternative Treatments

    Science.gov (United States)

    ... Find your chapter: search by state Home > Alzheimer's Disease > Treatments > Alternative Treatments Overview What Is Dementia? What Is Alzheimer's? Younger/Early Onset Facts and Figures Know the 10 Signs Stages Inside the Brain: ...

  8. Finding nonoverlapping substructures of a sparse matrix

    Energy Technology Data Exchange (ETDEWEB)

    Pinar, Ali; Vassilevska, Virginia

    2004-08-09

    Many applications of scientific computing rely on computations on sparse matrices, thus the design of efficient implementations of sparse matrix kernels is crucial for the overall efficiency of these applications. Due to the high compute-to-memory ratio and irregular memory access patterns, the performance of sparse matrix kernels is often far away from the peak performance on a modern processor. Alternative data structures have been proposed, which split the original matrix A into A{sub d} and A{sub s}, so that A{sub d} contains all dense blocks of a specified size in the matrix, and A{sub s} contains the remaining entries. This enables the use of dense matrix kernels on the entries of A{sub d} producing better memory performance. In this work, we study the problem of finding a maximum number of non overlapping rectangular dense blocks in a sparse matrix, which has not been studied in the sparse matrix community. We show that the maximum non overlapping dense blocks problem is NP-complete by using a reduction from the maximum independent set problem on cubic planar graphs. We also propose a 2/3-approximation algorithm for 2 times 2 blocks that runs in linear time in the number of nonzeros in the matrix. We discuss alternatives to rectangular blocks such as diagonal blocks and cross blocks and present complexity analysis and approximation algorithms.

  9. Chemically modified tetracyclines: The novel host modulating agents.

    Science.gov (United States)

    Swamy, Devulapalli Narasimha; Sanivarapu, Sahitya; Moogla, Srinivas; Kapalavai, Vasavi

    2015-01-01

    Periodontal pathogens and destructive host responses are involved in the initiation and progression of periodontitis. The emergence of host response modulation as a treatment concept has resulted from our improved understanding of the pathogenesis of periodontal disease. A variety of drugs have been evaluated as host modulation agents (HMA), including Non Steroidal Anti Inflammatory Drugs (NSAIDS), bisphosphonates, tetracyclines, enamel matrix proteins and bone morphogenetic proteins. Chemically modified tetracyclines (CMTs) are one such group of drugs which have been viewed as potential host modulating agents by their anticollagenolytic property. The CMTs are designed to be more potent inhibitors of pro inflammatory mediators and can increase the levels of anti inflammatory mediators. PMID:26392682

  10. Chemically modified tetracyclines: The novel host modulating agents

    Directory of Open Access Journals (Sweden)

    Devulapalli Narasimha Swamy

    2015-01-01

    Full Text Available Periodontal pathogens and destructive host responses are involved in the initiation and progression of periodontitis. The emergence of host response modulation as a treatment concept has resulted from our improved understanding of the pathogenesis of periodontal disease. A variety of drugs have been evaluated as host modulation agents (HMA, including Non Steroidal Anti Inflammatory Drugs (NSAIDS, bisphosphonates, tetracyclines, enamel matrix proteins and bone morphogenetic proteins. Chemically modified tetracyclines (CMTs are one such group of drugs which have been viewed as potential host modulating agents by their anticollagenolytic property. The CMTs are designed to be more potent inhibitors of pro inflammatory mediators and can increase the levels of anti inflammatory mediators.

  11. Web hosting for dummies

    CERN Document Server

    Pollock, Peter

    2013-01-01

    Host your own website or blog with this unique guide If you'd like to make the leap from a hosted environment to a self-hosted service, this book is for you. You may be making the move from casual blogging to professional blogging. Or, you might already be self-hosting, but want a good guide to show you how to get more out of your plan. In simple, easy-to-understand language, this helpful book breaks down all the functions of web hosting for self-hosted users, from setting up new e-mail accounts to backing up and securing your site, analyzing server logs, choosing a platform to ins

  12. Cosmic alternatives?

    Science.gov (United States)

    Gregory, Ruth

    2009-04-01

    "Cosmologists are often in error but never in doubt." This pithy characterization by the Soviet physicist Lev Landau sums up the raison d'être of Facts and Speculations in Cosmology. Authors Jayant Narlikar and Geoffrey Burbidge are proponents of a "steady state" theory of cosmology, and they argue that the cosmological community has become fixated on a "Big Bang" dogma, suppressing alternative viewpoints. This book very much does what it says on the tin: it sets out what is known in cosmology, and puts forward the authors' point of view on an alternative to the Big Bang.

  13. Supersymmetry in random matrix theory

    International Nuclear Information System (INIS)

    I study the applications of supersymmetry in random matrix theory. I generalize the supersymmetry method and develop three new approaches to calculate eigenvalue correlation functions. These correlation functions are averages over ratios of characteristic polynomials. In the first part of this thesis, I derive a relation between integrals over anti-commuting variables (Grassmann variables) and differential operators with respect to commuting variables. With this relation I rederive Cauchy- like integral theorems. As a new application I trace the supermatrix Bessel function back to a product of two ordinary matrix Bessel functions. In the second part, I apply the generalized Hubbard-Stratonovich transformation to arbitrary rotation invariant ensembles of real symmetric and Hermitian self-dual matrices. This extends the approach for unitarily rotation invariant matrix ensembles. For the k-point correlation functions I derive supersymmetric integral expressions in a unifying way. I prove the equivalence between the generalized Hubbard-Stratonovich transformation and the superbosonization formula. Moreover, I develop an alternative mapping from ordinary space to superspace. After comparing the results of this approach with the other two supersymmetry methods, I obtain explicit functional expressions for the probability densities in superspace. If the probability density of the matrix ensemble factorizes, then the generating functions exhibit determinantal and Pfaffian structures. For some matrix ensembles this was already shown with help of other approaches. I show that these structures appear by a purely algebraic manipulation. In this new approach I use structures naturally appearing in superspace. I derive determinantal and Pfaffian structures for three types of integrals without actually mapping onto superspace. These three types of integrals are quite general and, thus, they are applicable to a broad class of matrix ensembles. (orig.)

  14. Supersymmetry in random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Kieburg, Mario

    2010-05-04

    I study the applications of supersymmetry in random matrix theory. I generalize the supersymmetry method and develop three new approaches to calculate eigenvalue correlation functions. These correlation functions are averages over ratios of characteristic polynomials. In the first part of this thesis, I derive a relation between integrals over anti-commuting variables (Grassmann variables) and differential operators with respect to commuting variables. With this relation I rederive Cauchy- like integral theorems. As a new application I trace the supermatrix Bessel function back to a product of two ordinary matrix Bessel functions. In the second part, I apply the generalized Hubbard-Stratonovich transformation to arbitrary rotation invariant ensembles of real symmetric and Hermitian self-dual matrices. This extends the approach for unitarily rotation invariant matrix ensembles. For the k-point correlation functions I derive supersymmetric integral expressions in a unifying way. I prove the equivalence between the generalized Hubbard-Stratonovich transformation and the superbosonization formula. Moreover, I develop an alternative mapping from ordinary space to superspace. After comparing the results of this approach with the other two supersymmetry methods, I obtain explicit functional expressions for the probability densities in superspace. If the probability density of the matrix ensemble factorizes, then the generating functions exhibit determinantal and Pfaffian structures. For some matrix ensembles this was already shown with help of other approaches. I show that these structures appear by a purely algebraic manipulation. In this new approach I use structures naturally appearing in superspace. I derive determinantal and Pfaffian structures for three types of integrals without actually mapping onto superspace. These three types of integrals are quite general and, thus, they are applicable to a broad class of matrix ensembles. (orig.)

  15. Growing Alternatives

    DEFF Research Database (Denmark)

    Bagger-Petersen, Mai Corlin

    2014-01-01

    From 2014, Anhui Province will pilot a reform of the residential land market in China, thus integrating rural Anhui in the national housing market. In contrast, artist and activist Ou Ning has proposed the Bishan time money currency, intending to establish an alternative economic circuit in Bishan...

  16. A matrix lower bound

    Energy Technology Data Exchange (ETDEWEB)

    Grcar, Joseph F.

    2002-02-04

    A matrix lower bound is defined that generalizes ideas apparently due to S. Banach and J. von Neumann. The matrix lower bound has a natural interpretation in functional analysis, and it satisfies many of the properties that von Neumann stated for it in a restricted case. Applications for the matrix lower bound are demonstrated in several areas. In linear algebra, the matrix lower bound of a full rank matrix equals the distance to the set of rank-deficient matrices. In numerical analysis, the ratio of the matrix norm to the matrix lower bound is a condition number for all consistent systems of linear equations. In optimization theory, the matrix lower bound suggests an identity for a class of min-max problems. In real analysis, a recursive construction that depends on the matrix lower bound shows that the level sets of continuously differential functions lie asymptotically near those of their tangents.

  17. New Hosts of The Lassa Virus.

    Science.gov (United States)

    Olayemi, Ayodeji; Cadar, Daniel; Magassouba, N'Faly; Obadare, Adeoba; Kourouma, Fode; Oyeyiola, Akinlabi; Fasogbon, Samuel; Igbokwe, Joseph; Rieger, Toni; Bockholt, Sabrina; Jérôme, Hanna; Schmidt-Chanasit, Jonas; Garigliany, Mutien; Lorenzen, Stephan; Igbahenah, Felix; Fichet, Jean-Nicolas; Ortsega, Daniel; Omilabu, Sunday; Günther, Stephan; Fichet-Calvet, Elisabeth

    2016-01-01

    Lassa virus (LASV) causes a deadly haemorrhagic fever in humans, killing several thousand people in West Africa annually. For 40 years, the Natal multimammate rat, Mastomys natalensis, has been assumed to be the sole host of LASV. We found evidence that LASV is also hosted by other rodent species: the African wood mouse Hylomyscus pamfi in Nigeria, and the Guinea multimammate mouse Mastomys erythroleucus in both Nigeria and Guinea. Virus strains from these animals were isolated in the BSL-4 laboratory and fully sequenced. Phylogenetic analyses of viral genes coding for glycoprotein, nucleoprotein, polymerase and matrix protein show that Lassa strains detected in M. erythroleucus belong to lineages III and IV. The strain from H. pamfi clusters close to lineage I (for S gene) and between II &III (for L gene). Discovery of new rodent hosts has implications for LASV evolution and its spread into new areas within West Africa. PMID:27140942

  18. Adjoint Fermion Matrix Models

    OpenAIRE

    Makeenko, Yu.; Zarembo, K.

    1993-01-01

    We study fermionic one-matrix, two-matrix and $D$-dimensional gauge invariant matrix models. In all cases we derive loop equations which unambiguously determine the large-$N$ solution. For the one-matrix case the solution is obtained for an arbitrary interaction potential and turns out to be equivalent to the one for the Hermitean one-matrix model with a logarithmic potential and, therefore, belongs to the same universality class. The explicit solutions for the fermionic two-matrix and $D$-di...

  19. Ranks of dense alternating sign matrices and their sign patterns

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Gao, W.; Hall, F.J.; Jing, G.; Li, Z.; Stroev, M.

    2015-01-01

    Roč. 471, April (2015), s. 109-121. ISSN 0024-3795 R&D Projects: GA ČR(CZ) GA14-07880S Institutional support: RVO:67985840 Keywords : alternating sign matrix * dense matrix * sign pattern matrix Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014 http://www.sciencedirect.com/science/article/pii/S0024379515000257

  20. Alternative 23

    OpenAIRE

    Jackson, Mark

    2014-01-01

    Alternative 23 is a curated exhibition of works by Steve Aylett, David Blandy & Daniel Locke, Let Me Feel Your Finger First, Laura Oldfield Ford, Plastique Fantastique and Henrik Schrat, including the first screening of Let Me Feel Your Finger First’s Postcolonial Capers. In 1985 DC Comics in the US had taken the commercial decision to unify the complex and contradictory character story arcs from its various strips such as Superman, Batman and Green Lantern. The resultant crossover series...

  1. The Matrix Cookbook

    DEFF Research Database (Denmark)

    Petersen, Kaare Brandt; Pedersen, Michael Syskind

    Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices.......Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices....

  2. Matrix metalloproteinases and epileptogenesis

    OpenAIRE

    Ikonomidou, Chrysanthy

    2014-01-01

    Matrix metalloproteinases are vital drivers of synaptic remodeling in health and disease. It is suggested that at early stages of epileptogenesis, inhibition of matrix metalloproteinases may help ameliorate cell death, aberrant network rewiring, and neuroinflammation and prevent development of epilepsy.

  3. Matrix Tile Analysis

    OpenAIRE

    Givoni, Inmar; Cheung, Vincent; Frey, Brendan J.

    2012-01-01

    Many tasks require finding groups of elements in a matrix of numbers, symbols or class likelihoods. One approach is to use efficient bi- or tri-linear factorization techniques including PCA, ICA, sparse matrix factorization and plaid analysis. These techniques are not appropriate when addition and multiplication of matrix elements are not sensibly defined. More directly, methods like bi-clustering can be used to classify matrix elements, but these methods make the overly-restrictive assumptio...

  4. Matrix Order Differintegration

    OpenAIRE

    Naber, Mark

    2003-01-01

    The Riemann-Liouville formula for fractional derivatives and integrals (differintegration) is used to derive formulae for matrix order derivatives and integrals. That is, the parameter for integration and differentiation is allowed to assume matrix values. It is found that the computation of derivatives and integrals to matrix order is well defined for any square matrix over the complex numbers. Some properties are worked out for special classes of matrices. It is hoped that this new formalis...

  5. Biofilm Matrix Proteins

    OpenAIRE

    Fong, Jiunn N. C.; Yildiz, Fitnat H.

    2015-01-01

    Proteinaceous components of the biofilm matrix include secreted extracellular proteins, cell surface adhesins and protein subunits of cell appendages such as flagella and pili. Biofilm matrix proteins play diverse roles in biofilm formation and dissolution. They are involved in attaching cells to surfaces, stabilizing the biofilm matrix via interactions with exopolysaccharide and nucleic acid components, developing three-dimensional biofilm architectures, and dissolving biofilm matrix via enz...

  6. Matrix partitions of digraphs

    OpenAIRE

    Schell, David George

    2008-01-01

    The matrix partition problem has been of recent interest in graph theory. Matrix partitions generalize the study of graph colourings and homomorphisms. Many well-known graph partition problems can be stated in terms of matrices. For example skew partitions, split partitions, homogeneous sets, clique-cutsets, stable-cutsets and k-colourings can all be modeled as matrix partitions. For each matrix partition problem there is an equivalent trigraph H-colouring problem. We show a ‘dichotomy’ for t...

  7. Matrix with Prescribed Eigenvectors

    Science.gov (United States)

    Ahmad, Faiz

    2011-01-01

    It is a routine matter for undergraduates to find eigenvalues and eigenvectors of a given matrix. But the converse problem of finding a matrix with prescribed eigenvalues and eigenvectors is rarely discussed in elementary texts on linear algebra. This problem is related to the "spectral" decomposition of a matrix and has important technical…

  8. Repairing the Inconsistent Fuzzy Preference Matrix Using Multiobjective PSO

    Directory of Open Access Journals (Sweden)

    Abba Suganda Girsang

    2015-01-01

    Full Text Available This paper presents a method using multiobjective particle swarm optimization (PSO approach to improve the consistency matrix in analytic hierarchy process (AHP, called PSOMOF. The purpose of this method is to optimize two objectives which conflict each other, while improving the consistency matrix. They are minimizing consistent ratio (CR and deviation matrix. This study focuses on fuzzy preference matrix as one model comparison matrix in AHP. Some inconsistent matrices are repaired successfully to be consistent by this method. This proposed method offers some alternative consistent matrices as solutions.

  9. Energy alternatives

    International Nuclear Information System (INIS)

    Due to sharp rise in oil proces after the 1973 Arab-Israeli War, world attention has been focussed on the energy problem. At present the energy problem is limited to the cost and reliability of supply, even though there are enough supplies to go round. However, in the future the problem will be of availability, because in spite of the full exploitation of currently available conventional energy sources, the supply will fall short of demand which will always be increasing. Hence, there is need to develop alternate energy sources, including fast breeder reactors, fusion reactors and MHD. Economic and technical aspects of these energy are discussed. (M.G.B.)

  10. Alternative detente

    International Nuclear Information System (INIS)

    The influence of the Chernobyl accident on the disarmament and anti-nuclear movements is discussed. The accident directed attention towards the areas in common rather than the areas of disagreement. It also demonstrated the environmental impact of radioactivity, strengthening the ecological case of the anti-nuclear movement. The issues are discussed for the Western and Eastern bloc countries and the relationship between the two. Sections focus on the Eco-protest, Green politics and economics and on the politics of minority protest and the Green alternative. (U.K.)

  11. Bosonic Matrix Theory and Matrix Dbranes

    CERN Document Server

    Chaudhuri, S

    2002-01-01

    We develop new tools for an in-depth investigation of our recent proposal for Matrix Theory. We construct the anomaly-free and finite planar continuum limit of the ground state with SO(2^{13}) symmetry matching with the tadpole and tachyon free IR stable high temperature ground state of the open and closed bosonic string. The correspondence between large N limits and spacetime effective actions is demonstrated more generally for an arbitrary D25brane ground state which might include brane-antibrane pairs or NS-branes and which need not have an action formulation. Closure of the finite N matrix Lorentz algebra nevertheless requires that such a ground state is simultaneously charged under all even rank antisymmetric matrix potentials. Additional invariance under the gauge symmetry mediated by the one-form matrix potential requires a ground state charged under the full spectrum of antisymmetric (p+1)-form matrix potentials with p taking any integer value less than 26. Matrix Dbrane democracy has a beautiful larg...

  12. Laser Assisted Machining of Metal Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Metal matrix composites (MMC's) are of great interest in aerospace applications where their high specific strength provides a weight saving alternative to standard...

  13. Nanocrystal doped matrixes

    Science.gov (United States)

    Parce, J. Wallace; Bernatis, Paul; Dubrow, Robert; Freeman, William P.; Gamoras, Joel; Kan, Shihai; Meisel, Andreas; Qian, Baixin; Whiteford, Jeffery A.; Ziebarth, Jonathan

    2010-01-12

    Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.

  14. Alternative crops

    International Nuclear Information System (INIS)

    Surplus cereal production in the EEC and decreasing product prices, mainly for cereals, has prompted considerable interest for new earnings in arable farming. The objective was to examine whether suggested new crops (fibre, oil, medicinal and alternative grains crops) could be considered as real alternatives. Whether a specific crop can compete economically with cereals and whether there is a market demand for the crop is analyzed. The described possibilities will result in ca. 50,000 hectares of new crops. It is expected that they would not immediately provide increased earnings, but in the long run expected price developments are more positive than for cereals. The area for new crops will not solve the current surplus cereal problem as the area used for new crops is only 3% of that used for cereals. Preconditions for many new crops is further research activities and development work as well as the establishment of processing units and organizational initiatives. Presumably, it is stated, there will then be a basis for a profitable production of new crops for some farmers. (AB) (47 refs.)

  15. Modifying Matrix Materials to Increase Wetting and Adhesion

    Science.gov (United States)

    Zhong, Katie

    2011-01-01

    In an alternative approach to increasing the degrees of wetting and adhesion between the fiber and matrix components of organic-fiber/polymer matrix composite materials, the matrix resins are modified. Heretofore, it has been common practice to modify the fibers rather than the matrices: The fibers are modified by chemical and/or physical surface treatments prior to combining the fibers with matrix resins - an approach that entails considerable expense and usually results in degradation (typically, weakening) of fibers. The alternative approach of modifying the matrix resins does not entail degradation of fibers, and affords opportunities for improving the mechanical properties of the fiber composites. The alternative approach is more cost-effective, not only because it eliminates expensive fiber-surface treatments but also because it does not entail changes in procedures for manufacturing conventional composite-material structures. The alternative approach is best described by citing an example of its application to a composite of ultra-high-molecular- weight polyethylene (UHMWPE) fibers in an epoxy matrix. The epoxy matrix was modified to a chemically reactive, polarized epoxy nano-matrix to increase the degrees of wetting and adhesion between the fibers and the matrix. The modification was effected by incorporating a small proportion (0.3 weight percent) of reactive graphitic nanofibers produced from functionalized nanofibers into the epoxy matrix resin prior to combining the resin with the UHMWPE fibers. The resulting increase in fiber/matrix adhesion manifested itself in several test results, notably including an increase of 25 percent in the maximum fiber pullout force and an increase of 60-65 percent in fiber pullout energy. In addition, it was conjectured that the functionalized nanofibers became involved in the cross linking reaction of the epoxy resin, with resultant enhancement of the mechanical properties and lower viscosity of the matrix.

  16. Energy alternatives

    International Nuclear Information System (INIS)

    English. A special committe of the Canadian House of Commons was established on 23 May 1980 to investigate the use of alternative energy sources such as 'gasohol', liquified coal, solar energy, methanol, wind and tidal power, biomass, and propane. In its final report, the committee envisions an energy system for Canada based on hydrogen and electricity, using solar and geothermal energy for low-grade heat. The committe was not able to say which method of generating electricty would dominate in the next century, although it recommends that fossil fuels should not be used. The fission process is not specifically discussed, but the outlook for fusion was investigated, and continued governmental support of fusion research is recommended. The report proposes some improvements in governmental energy organizations and programs

  17. Parallelism in matrix computations

    CERN Document Server

    Gallopoulos, Efstratios; Sameh, Ahmed H

    2016-01-01

    This book is primarily intended as a research monograph that could also be used in graduate courses for the design of parallel algorithms in matrix computations. It assumes general but not extensive knowledge of numerical linear algebra, parallel architectures, and parallel programming paradigms. The book consists of four parts: (I) Basics; (II) Dense and Special Matrix Computations; (III) Sparse Matrix Computations; and (IV) Matrix functions and characteristics. Part I deals with parallel programming paradigms and fundamental kernels, including reordering schemes for sparse matrices. Part II is devoted to dense matrix computations such as parallel algorithms for solving linear systems, linear least squares, the symmetric algebraic eigenvalue problem, and the singular-value decomposition. It also deals with the development of parallel algorithms for special linear systems such as banded ,Vandermonde ,Toeplitz ,and block Toeplitz systems. Part III addresses sparse matrix computations: (a) the development of pa...

  18. Melvin Matrix Models

    CERN Document Server

    Motl, L

    2001-01-01

    In this short note we construct the DLCQ description of the flux seven-branes in type IIA string theory and discuss its basic properties. The matrix model involves dipole fields. We explain the relation of this nonlocal matrix model to various orbifolds. We also give a spacetime interpretation of the Seiberg-Witten-like map, proposed in a different context first by Bergman and Ganor, that converts this matrix model to a local, highly nonlinear theory.

  19. Parasite host range and the evolution of host resistance.

    Science.gov (United States)

    Gorter, F A; Hall, A R; Buckling, A; Scanlan, P D

    2015-05-01

    Parasite host range plays a pivotal role in the evolution and ecology of hosts and the emergence of infectious disease. Although the factors that promote host range and the epidemiological consequences of variation in host range are relatively well characterized, the effect of parasite host range on host resistance evolution is less well understood. In this study, we tested the impact of parasite host range on host resistance evolution. To do so, we used the host bacterium Pseudomonas fluorescens SBW25 and a diverse suite of coevolved viral parasites (lytic bacteriophage Φ2) with variable host ranges (defined here as the number of host genotypes that can be infected) as our experimental model organisms. Our results show that resistance evolution to coevolved phages occurred at a much lower rate than to ancestral phage (approximately 50% vs. 100%), but the host range of coevolved phages did not influence the likelihood of resistance evolution. We also show that the host range of both single parasites and populations of parasites does not affect the breadth of the resulting resistance range in a naïve host but that hosts that evolve resistance to single parasites are more likely to resist other (genetically) more closely related parasites as a correlated response. These findings have important implications for our understanding of resistance evolution in natural populations of bacteria and viruses and other host-parasite combinations with similar underlying infection genetics, as well as the development of phage therapy. PMID:25851735

  20. Modular Matrix Models

    OpenAIRE

    He, Y.; Jejjala, V.

    2003-01-01

    Inspired by a formal resemblance of certain q-expansions of modular forms and the master field formalism of matrix models in terms of Cuntz operators, we construct a Hermitian one-matrix model, which we dub the ``modular matrix model.'' Together with an N=1 gauge theory and a special Calabi-Yau geometry, we find a modular matrix model that naturally encodes the Klein elliptic j-invariant, and hence, by Moonshine, the irreducible representations of the Fischer-Griess Monster group.

  1. Matrix Model for Choosing Green Marketing Sustainable Strategic Alternatives

    OpenAIRE

    Cătălina Sitnikov; Laura Vasilescu; Radu Ogarcă; Sorin Tudor

    2015-01-01

    Green marketing examines the symbiotic role played by marketing in ensuring sustainable business, exploring issues concerning the environment and the way strategic decisions can influence it. At present, the environmental issues concern more and more the competitive approach any organization can implement. Based on this approach, organizations can gain competitive advantage by managing environmental variables and by developing and implementing green marketing strategies. Considering the impor...

  2. Matrix metalloproteinases and epileptogenesis.

    Science.gov (United States)

    Ikonomidou, Chrysanthy

    2014-12-01

    Matrix metalloproteinases are vital drivers of synaptic remodeling in health and disease. It is suggested that at early stages of epileptogenesis, inhibition of matrix metalloproteinases may help ameliorate cell death, aberrant network rewiring, and neuroinflammation and prevent development of epilepsy. PMID:26567100

  3. Matrix comparison, Part 2

    DEFF Research Database (Denmark)

    Schneider, Jesper Wiborg; Borlund, Pia

    2007-01-01

    The present two-part article introduces matrix comparison as a formal means for evaluation purposes in informetric studies such as cocitation analysis. In the first part, the motivation behind introducing matrix comparison to informetric studies, as well as two important issues influencing such...... comparisons, matrix generation, and the composition of proximity measures, are introduced and discussed. In this second part, the authors introduce and thoroughly demonstrate two related matrix comparison techniques the Mantel test and Procrustes analysis, respectively. These techniques can compare and...... evaluate the degree of monotonicity between different proximity measures or their ordination results. In common with these techniques is the application of permutation procedures to test hypotheses about matrix resemblances. The choice of technique is related to the validation at hand. In the case of the...

  4. Time rate collision matrix

    International Nuclear Information System (INIS)

    The collision integral terms in Boltzmann equation are reformulated numerically leading to the substitution of the multiple integrals with a multiplicative matrix of the two colliding species velocity distribution functions which varies with the differential collision cross section. A matrix of lower rank may be constructed when one of the distribution functions is specified, in which case the matrix elements represent kinetic transition probabilities in the velocity space and the multiplication of the time rate collision matrix with the unknown velocity distribution function expresses the time rate of change of the distribution. The collision matrix may be used to describe the time evolution of systems in nonequilibrium conditions, to evaluate the rate of momentum and energy transfer between given species, or to generate validity criteria for linearized kinetic equations

  5. Double coincidence matrix

    International Nuclear Information System (INIS)

    To increase the accuracy of discrimination of true coincidences against the background of accidental ones, circuit has been developed which operates on the principle of dynamic equalization of resolution times of two coincidence circuits. The flowsheet of a 4x6 double-coincidence matrix is given. The principal elements of the matrix are commutators and output signal shapers. The matrix uses 138-series microcircuits. The resolution time of coincidence circuits is 10 ns, the dead time is 25 ns. The results of testing the matrix during experiments under conditions of a high background of accidental coincidences (70-90%) have shown that the accuracy of discrimination of true coincidences with the help of the double-coincidence matrix approximates the accuracy of time-to-digital converters within the limits of the statistical accuracy

  6. Fuzzy vulnerability matrix

    International Nuclear Information System (INIS)

    The so-called vulnerability matrix is used in the evaluation part of the probabilistic safety assessment for a nuclear power plant, during the containment event trees calculations. This matrix is established from what is knows as Numerical Categories for Engineering Judgement. This matrix is usually established with numerical values obtained with traditional arithmetic using the set theory. The representation of this matrix with fuzzy numbers is much more adequate, due to the fact that the Numerical Categories for Engineering Judgement are better represented with linguistic variables, such as 'highly probable', 'probable', 'impossible', etc. In the present paper a methodology to obtain a Fuzzy Vulnerability Matrix is presented, starting from the recommendations on the Numerical Categories for Engineering Judgement. (author)

  7. Alternative Splice in Alternative Lice.

    Science.gov (United States)

    Tovar-Corona, Jaime M; Castillo-Morales, Atahualpa; Chen, Lu; Olds, Brett P; Clark, John M; Reynolds, Stuart E; Pittendrigh, Barry R; Feil, Edward J; Urrutia, Araxi O

    2015-10-01

    Genomic and transcriptomics analyses have revealed human head and body lice to be almost genetically identical; although con-specific, they nevertheless occupy distinct ecological niches and have differing feeding patterns. Most importantly, while head lice are not known to be vector competent, body lice can transmit three serious bacterial diseases; epidemictyphus, trench fever, and relapsing fever. In order to gain insights into the molecular bases for these differences, we analyzed alternative splicing (AS) using next-generation sequencing data for one strain of head lice and one strain of body lice. We identified a total of 3,598 AS events which were head or body lice specific. Exon skipping AS events were overrepresented among both head and body lice, whereas intron retention events were underrepresented in both. However, both the enrichment of exon skipping and the underrepresentation of intron retention are significantly stronger in body lice compared with head lice. Genes containing body louse-specific AS events were found to be significantly enriched for functions associated with development of the nervous system, salivary gland, trachea, and ovarian follicle cells, as well as regulation of transcription. In contrast, no functional categories were overrepresented among genes with head louse-specific AS events. Together, our results constitute the first evidence for transcript pool differences in head and body lice, providing insights into molecular adaptations that enabled human lice to adapt to clothing, and representing a powerful illustration of the pivotal role AS can play in functional adaptation. PMID:26169943

  8. Looking for an Alternative.

    Science.gov (United States)

    Kennedy, Jack

    1999-01-01

    Argues that high school newspapers might do well to create stronger ties with alternative weeklies. Discusses issues of niche marketing, alternative content, and alternative presentation. Notes that high school papers could learn a lot from alternative newspapers. (SR)

  9. Providing Learning Computing Labs using Hosting and Virtualization Technologies

    Directory of Open Access Journals (Sweden)

    Armide González

    2011-05-01

    Full Text Available This paper presents a computing hosting system to provide virtual computing laboratories for learning activities. This system is based on hosting and virtualization technologies. All the components used in its development are free software tools. The computing lab model provided by the system is a more sustainable and scalable alternative than the traditional academic computing lab, and it requires lower costs of installation and operation.

  10. Alternative waste forms: a comparative study

    International Nuclear Information System (INIS)

    A characterization study utilizing comparative tests has been conducted to assess product inertness of alternative waste form materials, having evaluated at this point four basic product types: sintered ceramics, glass ceramics, glass and concrete. The seven specific waste form materials studied represent simulated nuclear waste loading of 5% to 100%, processed between room temperature and 12000C and subjected to characterization tests including phase analysis, microstructure, compression testing, volatility and leach testing. Significant conclusions based upon the results obtained to date are: sintered calcine waste form PW-9 does not retain Na, Mo and Cs when leached 900C and, in fact, does not remain a solid; glass and supercalcine are alike under both hydrous and hydrothermal leach conditions with glass exhibiting a greater retention of sodium and molybdenum, supercalcine having a greater retention of cesium, and both forms approximately equal in strontium retention; volatility measurements indicate that an order of magnitude decrease in volatility occurs when a calcine waste form is incorporated in a crystalline or glassy host; glass 76-68 is superior to supercalcine SPC-5B in retention of volatiles below 11000C because of the high release of Na from SPC-5B, however, as the temperature approaches or exceeds the glass melt temperature, volatile losses of the glass equal or exceed that of SPC-5B; glass 76-68 and supercalcine SPC-5B have high compressive strengths when compared to sintered PW-9 and cement products. This is apparently due to a stronger continuum bond resulting from a glassy matrix or crystalline ingrowth over a simple mechanical agglomeration of particles

  11. Patience of matrix games

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.;

    2013-01-01

    For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...... strategy uses a nonzero probability as small as image. This is done by constructing an explicit image nonsingular image matrix, for which the inverse has only nonnegative entries and where some of the entries are of value image....

  12. Faces of matrix models

    CERN Document Server

    Morozov, A

    2012-01-01

    Partition functions of eigenvalue matrix models possess a number of very different descriptions: as matrix integrals, as solutions to linear and non-linear equations, as tau-functions of integrable hierarchies and as special-geometry prepotentials, as result of the action of W-operators and of various recursions on elementary input data, as gluing of certain elementary building blocks. All this explains the central role of such matrix models in modern mathematical physics: they provide the basic "special functions" to express the answers and relations between them, and they serve as a dream model of what one should try to achieve in any other field.

  13. Quivers from Matrix Factorizations

    CERN Document Server

    Aspinwall, Paul S

    2010-01-01

    We discuss how matrix factorizations offer a practical method of computing the quiver and associated superpotential for a hypersurface singularity. This method also yields explicit geometrical interpretations of D-branes (i.e., quiver representations) on a resolution given in terms of Grassmannians. As an example we analyze some non-toric singularities which are resolved by a single CP1 but have "length" greater than one. These examples have a much richer structure than conifolds. A picture is proposed that relates matrix factorizations in Landau-Ginzburg theories to the way that matrix factorizations are used in this paper to perform noncommutative resolutions.

  14. Elementary matrix theory

    CERN Document Server

    Eves, Howard

    1980-01-01

    The usefulness of matrix theory as a tool in disciplines ranging from quantum mechanics to psychometrics is widely recognized, and courses in matrix theory are increasingly a standard part of the undergraduate curriculum.This outstanding text offers an unusual introduction to matrix theory at the undergraduate level. Unlike most texts dealing with the topic, which tend to remain on an abstract level, Dr. Eves' book employs a concrete elementary approach, avoiding abstraction until the final chapter. This practical method renders the text especially accessible to students of physics, engineeri

  15. N-matrix completion problem

    OpenAIRE

    Araújo, C. Mendes; Juan R. Torregrosa; Urbano, Ana M.

    2003-01-01

    An n x n matrix is called an N-matrix if all principal minors are negative. In this paper, we are interested in N-matrix completion problems, that is, when a partial N-matrix hás an N-matrix completion. In general, a combinatorially or non-combinatorially symmetric partial N-matrix does not have an N-matrix completion. Here we prove that a combinatorially symmetric partial N-matrix has an N-matrix completion if the graph of its specified entries is a 1-chordal graph. We also prove that there ...

  16. A Multilevel Approach For Nonnegative Matrix Factorization

    CERN Document Server

    Gillis, Nicolas

    2010-01-01

    Nonnegative Matrix Factorization (NMF) is the problem of approximating a nonnegative matrix with the product of two low-rank nonnegative matrices and has been shown to be particularly useful in many applications, e.g., in text mining, image processing, computational biology, etc. In this paper, we explain how algorithms for NMF can be embedded into the framework of multilevel methods in order to accelerate their convergence. This technique can be applied in situations where data admit a good approximate representation in a lower dimensional space through linear transformations preserving nonnegativity. A simple multilevel strategy is described and is experimentally shown to speed up significantly three popular NMF algorithms (alternating nonnegative least squares, multiplicative updates and hierarchical alternating least squares) on several standard image datasets.

  17. Matrix-Free Approximate Equilibration

    OpenAIRE

    Bradley, Andrew M.; Murray, Walter

    2011-01-01

    The condition number of a diagonally scaled matrix, for appropriately chosen scaling matrices, is often less than that of the original. Equilibration scales a matrix so that the scaled matrix's row and column norms are equal. Scaling can be approximate. We develop approximate equilibration algorithms for nonsymmetric and symmetric matrices having signed elements that access a matrix only by matrix-vector products.

  18. High Metallicity LGRB Hosts

    CERN Document Server

    Graham, J F; Levesque, E M; Kewley, L J; Tanvir, N R; Levan, A J; Patel, S K; Misra, K; Huang, K -H; Reichart, D E; Nysewander, M; Schady, P

    2015-01-01

    We present our imaging and spectroscopic observations of the host galaxies of two dark long bursts with anomalously high metallicities, LGRB 051022 and LGRB 020819B, which in conjunction with another LGRB event with an optical afterglow comprise the three LGRBs with high metallicity host galaxies in the Graham & Fruchter (2013) sample. In Graham & Fruchter (2013), we showed that LGRBs exhibit a strong and apparently intrinsic preference for low metallicity environments (12+log(O/H) < 8.4 in the KK04 scale) in spite of these three cases with abundances of about solar and above. These exceptions however are consistent with the general star-forming galaxy population of comparable brightness & redshift. This is surprising: even among a preselected sample of high metallicity LGRBs, were the metal aversion to remain in effect for these objects, we would expect their metallicity to still be lower than the typical metallicity for the galaxies at that luminosity and redshift. Therefore we deduce that it...

  19. Hosting a Katrina Evacuee.

    Science.gov (United States)

    Hoagland, David

    2008-03-01

    No individual or institution anticipated the impact on the academic research community of hurricane Katrina. When Tulane physicist Wayne Reed asked me to host his research group just a day or two after the disaster, with no authorization or understanding of the commitment, I agreed immediately and then pondered implications. Fortunately, colleagues helped in making the commitment real, only the bureaucracy of my public university posing small hindrances. Industry was remarkably generous in providing Reed with significant ``loaner'' equipment, and amazingly, a suite of custom Reed experiments was running within weeks. At the end, the most productive collaborations for Reed seemed not to have been with my group, with its similar research, but to other groups at my institution, particularly the synthetic chemists, who gained access to methods previously unique to Tulane while offering samples previously unique to UMass. Quickly designed projects exploiting this match turned out remarkably productive. Although begun with trepidation, hosting of Reed had huge positive benefits to me and UMass, and I believe, also to Reed and Tulane. Some key lessons for the future: (i) industry has capacity and willingness to help academic research during disruption (ii) commitment of a host institution must be immediate, without a wait for formal approvals or arrangement of special funding -- delay leads only to discouragement, (iii) continuing academic progress of displaced students must come first, and (iv) intellectual synergy rather than overlap should be the basis for seeking a host. Lastly, NSF or other funding agency should consider a program directly addressing the research needs of unexpectedly disrupted academic scientists, and most particularly, graduate students who face greatly extended studies.

  20. IPv6 host fingerprint

    OpenAIRE

    Nerakis, Eleftherios

    2006-01-01

    Approved for public release, distribution unlimited This thesis explores ways of using probe packets to identify the type and version of OS that is run by a remote IPv6 host. Such a probing technique can be effective because developers of different OSes often interpret the guidance provided by the RFCs slightly differently, and consequently their network protocol stack implementation may generate responses bearing unique markers to certain probing packets. The key challenge is to find suit...

  1. Method for multiple attribute decision making based on incomplete linguistic judgment matrix

    Institute of Scientific and Technical Information of China (English)

    Zhang Yao; Fan Zhiping

    2008-01-01

    With respect to the multiple attribute decision making problems with linguistic preference relations on alternatives in the form of incomplete linguistic judgment matrix, a method is proposed to analyze the decision problem. The incomplete linguistic judgment matrix is transformed into incomplete fuzzy judgment matrix and an optimization model is developed on the basis of incomplete fuzzy judgment matrix provided by the decision maker and the decision matrix to determine attribute weights by Lag)range multiplier method. Then the overall values of all alternatives are calculated to rank them. A numerical example is given to illustrate the feasibility and practicality of the proposed method.

  2. A novel color image encryption scheme using alternate chaotic mapping structure

    Science.gov (United States)

    Wang, Xingyuan; Zhao, Yuanyuan; Zhang, Huili; Guo, Kang

    2016-07-01

    This paper proposes an color image encryption algorithm using alternate chaotic mapping structure. Initially, we use the R, G and B components to form a matrix. Then one-dimension logistic and two-dimension logistic mapping is used to generate a chaotic matrix, then iterate two chaotic mappings alternately to permute the matrix. For every iteration, XOR operation is adopted to encrypt plain-image matrix, then make further transformation to diffuse the matrix. At last, the encrypted color image is obtained from the confused matrix. Theoretical analysis and experimental results has proved the cryptosystem is secure and practical, and it is suitable for encrypting color images.

  3. Pesticide-Exposure Matrix

    Science.gov (United States)

    The "Pesticide-exposure Matrix" was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years.

  4. The Hill Interaction Matrix

    Science.gov (United States)

    Hill, William Fawcett

    1971-01-01

    Leadership style, group composition, and group development are simultaneously quantified through the use of the matrix. It represents an attempt to objectify the art of group therapy. Comment by Richard C. Rank follows. (Author)

  5. The Matrix Organization Revisited

    DEFF Research Database (Denmark)

    Gattiker, Urs E.; Ulhøi, John Parm

    1999-01-01

    This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....

  6. Matrix Big Brunch

    OpenAIRE

    Bedford, J; Papageorgakis, C.; Rodriguez-Gomez, D.; Ward, J.

    2007-01-01

    Following the holographic description of linear dilaton null Cosmologies with a Big Bang in terms of Matrix String Theory put forward by Craps, Sethi and Verlinde, we propose an extended background describing a Universe including both Big Bang and Big Crunch singularities. This belongs to a class of exact string backgrounds and is perturbative in the string coupling far away from the singularities, both of which can be resolved using Matrix String Theory. We provide a simple theory capable of...

  7. Matrix string interactions

    OpenAIRE

    Periwal, Vipul; Tafjord, Oyvind

    1998-01-01

    String configurations have been identified in compactified Matrix theory at vanishing string coupling. We show how the interactions of these strings are determined by the Yang-Mills gauge field on the worldsheet. At finite string coupling, this suggests the underlying dynamics is not well-approximated as a theory of strings. This may explain why string perturbation theory diverges badly, while Matrix string perturbation theory presumably has a perturbative expansion with properties similar to...

  8. Planets, debris and their host metallicity correlations

    CERN Document Server

    Fletcher, Mark

    2016-01-01

    Recent observations of debris discs, believed to be made up of remnant planetesimals, brought a number of surprises. Debris disc presence does not correlate with the host star's metallicity, and may anti-correlate with the presence of gas giant planets. These observations contradict both assumptions and predictions of the highly successful Core Accretion model of planet formation. Here we explore predictions of the alternative Tidal Downsizing (TD) scenario of planet formation. In TD, small planets and planetesimal debris is made only when gas fragments, predecessors of giant planets, are tidally disrupted. We show that these disruptions are rare in discs around high metallicity stars but release more debris per disruption than their low [M/H] analogs. This predicts no simple relation between debris disc presence and host star's [M/H], as observed. A detected gas giant planet implies in TD that its predecessor fragment was not disputed, potentially explaining why DDs are less likely to be found around stars w...

  9. Bosonic Matrix Theory and Matrix Dbranes

    OpenAIRE

    Chaudhuri, Shyamoli

    2002-01-01

    We develop new tools for an in-depth study of our recent proposal for Matrix Theory. We construct the anomaly-free and finite planar continuum limit of the ground state with SO(2^{13}) symmetry matching with the tadpole and tachyon free IR stable high temperature ground state of the open and closed bosonic string. The correspondence between large N limits and spacetime effective actions is demonstrated more generally for an arbitrary D25brane ground state which might include brane-antibrane p...

  10. SHEAR WAVES IN PERIODIC WAVEGUIDE WITH ALTERNATING BOUNDARY CONDITIONS

    OpenAIRE

    Piliposyan D.G.; Ghazaryan R.A.; Ghazaryan K.B.

    2014-01-01

    The propagation of shear waves in elastic waveguide of periodic structure consisting of three different materials with alternating along the guide walls boundary conditions is investigated. Using the transfer matrix approach the problem is reduced to the solution of a block transfer matrix eigenvalue problem. Bloth the dispersion and the band gap structure analysis have been carried out numerically. It is shown that for alternating boundary conditions along the waveguide walls, by modulating ...

  11. Comparing mechanisms of host manipulation across host and parasite taxa

    Science.gov (United States)

    Lafferty, Kevin D.; Shaw, Jenny C.

    2013-01-01

    Parasites affect host behavior in several ways. They can alter activity, microhabitats or both. For trophically transmitted parasites (the focus of our study), decreased activity might impair the ability of hosts to respond to final-host predators, and increased activity and altered microhabitat choice might increase contact rates between hosts and final-host predators. In an analysis of trophically transmitted parasites, more parasite groups altered activity than altered microhabitat choice. Parasites that infected vertebrates were more likely to impair the host’s reaction to predators, whereas parasites that infected invertebrates were more likely to increase the host’s contact with predators. The site of infection might affect how parasites manipulate their hosts. For instance, parasites in the central nervous system seem particularly suited to manipulating host behavior. Manipulative parasites commonly occupy the body cavity, muscles and central nervous systems of their hosts. Acanthocephalans in the data set differed from other taxa in that they occurred exclusively in the body cavity of invertebrates. In addition, they were more likely to alter microhabitat choice than activity. Parasites in the body cavity (across parasite types) were more likely to be associated with increased host contact with predators. Parasites can manipulate the host through energetic drain, but most parasites use more sophisticated means. For instance, parasites target four physiological systems that shape behavior in both invertebrates and vertebrates: neural, endocrine, neuromodulatory and immunomodulatory. The interconnections between these systems make it difficult to isolate specific mechanisms of host behavioral manipulation.

  12. Max–min distance nonnegative matrix factorization

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-10-26

    Nonnegative Matrix Factorization (NMF) has been a popular representation method for pattern classification problems. It tries to decompose a nonnegative matrix of data samples as the product of a nonnegative basis matrix and a nonnegative coefficient matrix. The columns of the coefficient matrix can be used as new representations of these data samples. However, traditional NMF methods ignore class labels of the data samples. In this paper, we propose a novel supervised NMF algorithm to improve the discriminative ability of the new representation by using the class labels. Using the class labels, we separate all the data sample pairs into within-class pairs and between-class pairs. To improve the discriminative ability of the new NMF representations, we propose to minimize the maximum distance of the within-class pairs in the new NMF space, and meanwhile to maximize the minimum distance of the between-class pairs. With this criterion, we construct an objective function and optimize it with regard to basis and coefficient matrices, and slack variables alternatively, resulting in an iterative algorithm. The proposed algorithm is evaluated on three pattern classification problems and experiment results show that it outperforms the state-of-the-art supervised NMF methods.

  13. Biocompatible 3D Matrix with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Alberto Ion

    2016-01-01

    Full Text Available The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL, hydroxyapatite (HAp, β-cyclodextrin (β-CD and usnic acid (UA. The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM, Fourier Transform Infrared Microscopy (FT-IRM, Transmission Electron Microscopy (TEM, and X-ray Diffraction (XRD. In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D anti-infective regeneration matrix for bone tissue engineering.

  14. Matrix Information Geometry

    CERN Document Server

    Bhatia, Rajendra

    2013-01-01

    This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR).  During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented  are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.  

  15. Predicting structure in nonsymmetric sparse matrix factorizations

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, J.R. [Xerox Palo Alto Research Center, CA (United States); Ng, E.G. [Oak Ridge National Lab., TN (United States)

    1992-10-01

    Many computations on sparse matrices have a phase that predicts the nonzero structure of the output, followed by a phase that actually performs the numerical computation. We study structure prediction for computations that involve nonsymmetric row and column permutations and nonsymmetric or non-square matrices. Our tools are bipartite graphs, matchings, and alternating paths. Our main new result concerns LU factorization with partial pivoting. We show that if a square matrix A has the strong Hall property (i.e., is fully indecomposable) then an upper bound due to George and Ng on the nonzero structure of L + U is as tight as possible. To show this, we prove a crucial result about alternating paths in strong Hall graphs. The alternating-paths theorem seems to be of independent interest: it can also be used to prove related results about structure prediction for QR factorization that are due to Coleman, Edenbrandt, Gilbert, Hare, Johnson, Olesky, Pothen, and van den Driessche.

  16. Matrix interdiction problem

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory

    2010-01-01

    In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.

  17. Dynamic Matrix Rank

    DEFF Research Database (Denmark)

    Frandsen, Gudmund Skovbjerg; Frandsen, Peter Frands

    2009-01-01

    We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entries...... in a single column of the matrix. We also give an algorithm that maintains the rank using O(n2) arithmetic operations per rank one update. These bounds appear to be the first nontrivial bounds for the problem. The upper bounds are valid for arbitrary fields, whereas the lower bound is valid for...... algebraically closed fields. The upper bound for element updates uses fast rectangular matrix multiplication, and the lower bound involves further development of an earlier technique for proving lower bounds for dynamic computation of rational functions....

  18. MATLAB matrix algebra

    CERN Document Server

    Pérez López, César

    2014-01-01

    MATLAB is a high-level language and environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spreadsheets or traditional programming languages, such as C/C++ or Java. MATLAB Matrix Algebra introduces you to the MATLAB language with practical hands-on instructions and results, allowing you to quickly achieve your goals. Starting with a look at symbolic and numeric variables, with an emphasis on vector and matrix variables, you will go on to examine functions and operations that support vectors and matrices as arguments, including those based on analytic parent functions. Computational methods for finding eigenvalues and eigenvectors of matrices are detailed, leading to various matrix decompositions. Applications such as change of bases, the classification of quadratic forms and ...

  19. D-Glucose as a modifying agent in gelatin/collagen matrix and reservoir nanoparticles for Calendula officinalis delivery.

    Science.gov (United States)

    Lam, P-L; Kok, S H-L; Bian, Z-X; Lam, K-H; Tang, J C-O; Lee, K K-H; Gambari, R; Chui, C-H

    2014-05-01

    Gelatin/Collagen-based matrix and reservoir nanoparticles require crosslinkers to stabilize the formed nanosuspensions, considering that physical instability is the main challenge of nanoparticulate systems. The use of crosslinkers improves the physical integrity of nanoformulations under the-host environment. Aldehyde-based fixatives, such as formaldehyde and glutaraldehyde, have been widely applied to the crosslinking process of polymeric nanoparticles. However, their potential toxicity towards human beings has been demonstrated in many previous studies. In order to tackle this problem, D-glucose was used during nanoparticle formation to stabilize the gelatin/collagen-based matrix wall and reservoir wall for the deliveries of Calendula officinalis powder and oil, respectively. In addition, therapeutic selectivity between malignant and normal cells could be observed. The C. officinalis powder loaded nanoparticles significantly strengthened the anti-cancer effect towards human breast adenocarcinoma MCF7 cells and human hepatoma SKHep1 cells when compared with the free powder. On the contrary, the nanoparticles did not show significant cytotoxicity towards normal esophageal epithelial NE3 cells and human skin keratinocyte HaCaT cells. On the basis of these evidences, D-glucose modified gelatin/collagen matrix nanoparticles containing C. officinalis powder might be proposed as a safer alternative vehicle for anti-cancer treatments. PMID:24657927

  20. DIY Bertin Matrix

    OpenAIRE

    Perin, Charles; Le Goc, Mathieu; Di Vozzo, Romain; Fekete, Jean-Daniel; Dragicevic, Pierre

    2015-01-01

    In this paper, we relate the iterative fabrication of a physical Bertin Matrix. Jacques Bertin designed and refined such devices over 10 years (1970–1980) and five iterations of what he called Dominos 1–5. For the purpose of an exhibit dedicated to Bertin's work during VIS 2014 in Paris, we designed an improved version of such device by leveraging modern fabrication possibilities and in particular a laser cutter. We describe the process, iterations and improvements of our matrix, and report l...

  1. A nonsupersymmetric matrix orbifold

    OpenAIRE

    Banks, Tom; Motl, Lubos

    1999-01-01

    We construct the matrix description for a twisted version of the IIA string theory on S^1 with fermions antiperiodic around a spatial circle. The result is a 2+1-dimensional U(N) x U(N) nonsupersymmetric Yang-Mills theory with fermionic matter transforming in the (N,Nbar). The two U(N)'s are exchanged if one goes around a twisted circle of the worldvolume. Relations with Type 0 theories are explored and we find Type 0 matrix string limits of our gauge theory. We argue however that most of the...

  2. Complex matrix model duality

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.W.

    2010-11-15

    The same complex matrix model calculates both tachyon scattering for the c=1 non-critical string at the self-dual radius and certain correlation functions of half-BPS operators in N=4 super- Yang-Mills. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is mirrored by the duality of their Feynman diagrams. Analogously to the Hermitian Kontsevich- Penner model, the correlation functions of the second model can be written as sums over discrete points in subspaces of the moduli space of punctured Riemann surfaces. (orig.)

  3. Complex matrix model duality

    International Nuclear Information System (INIS)

    The same complex matrix model calculates both tachyon scattering for the c=1 non-critical string at the self-dual radius and certain correlation functions of half-BPS operators in N=4 super- Yang-Mills. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is mirrored by the duality of their Feynman diagrams. Analogously to the Hermitian Kontsevich- Penner model, the correlation functions of the second model can be written as sums over discrete points in subspaces of the moduli space of punctured Riemann surfaces. (orig.)

  4. Reduced Google matrix

    CERN Document Server

    Frahm, K M

    2016-01-01

    Using parallels with the quantum scattering theory, developed for processes in nuclear and mesoscopic physics and quantum chaos, we construct a reduced Google matrix $G_R$ which describes the properties and interactions of a certain subset of selected nodes belonging to a much larger directed network. The matrix $G_R$ takes into account effective interactions between subset nodes by all their indirect links via the whole network. We argue that this approach gives new possibilities to analyze effective interactions in a group of nodes embedded in a large directed networks. Possible efficient numerical methods for the practical computation of $G_R$ are also described.

  5. Elementary matrix algebra

    CERN Document Server

    Hohn, Franz E

    2012-01-01

    This complete and coherent exposition, complemented by numerous illustrative examples, offers readers a text that can teach by itself. Fully rigorous in its treatment, it offers a mathematically sound sequencing of topics. The work starts with the most basic laws of matrix algebra and progresses to the sweep-out process for obtaining the complete solution of any given system of linear equations - homogeneous or nonhomogeneous - and the role of matrix algebra in the presentation of useful geometric ideas, techniques, and terminology.Other subjects include the complete treatment of the structur

  6. Matrixed business support comparison study.

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, Josh D.

    2004-11-01

    The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.

  7. Matrix fluid chemistry experiment. Final report June 1998 - March 2003

    International Nuclear Information System (INIS)

    The Matrix Fluid Chemistry Experiment set out to determine the composition and evolution of matrix pore fluids/waters in low permeable rock located at repository depths in the Aespoe Hard Rock Laboratory (HRL). Matrix pore fluids/waters can be highly saline in composition and, if accessible, may influence the near-field groundwater chemistry of a repository system. Characterising pore fluids/waters involved in-situ borehole sampling and analysis integrated with laboratory studies and experiments on rock matrix drill core material. Relating the rate of in-situ pore water accumulation during sampling to the measured rock porosity indicated a hydraulic conductivity of 10-14-10-13 m/s for the rock matrix. This was in accordance with earlier estimated predictions. The sampled matrix pore water, brackish in type, mostly represents older palaeo- groundwater mixtures preserved in the rock matrix and dating back to at least the last glaciation. A component of matrix pore 'fluid' is also present. One borehole section suggests a younger groundwater component which has accessed the rock matrix during the experiment. There is little evidence that the salinity of the matrix pore waters has been influenced significantly by fluid inclusion populations hosted by quartz. Crush/leach, cation exchange, pore water diffusion and pore water displacement laboratory experiments were carried out to compare extracted/calculated matrix pore fluids/waters with in-situ sampling. Of these the pore water diffusion experiments appear to be the most promising approach and a recommended site characterisation protocol has been formulated. The main conclusions from the Matrix Fluid Chemistry Experiment are: Groundwater movement within the bedrock hosting the experimental site has been enhanced by increased hydraulic gradients generated by the presence of the tunnel, and to a much lesser extent by the borehole itself. Over experimental timescales ∼4 years) solute transport through the rock matrix is

  8. Matrix fluid chemistry experiment. Final report June 1998 - March 2003

    Energy Technology Data Exchange (ETDEWEB)

    Smellie, John A.T. [Conterra AB, Luleaa (Sweden); Waber, H. Niklaus [Univ. of Bern (Switzerland). Inst. of Geology; Frape, Shaun K. [Univ. of Waterloo (Canada). Dept. of Earth Sciences

    2003-06-01

    The Matrix Fluid Chemistry Experiment set out to determine the composition and evolution of matrix pore fluids/waters in low permeable rock located at repository depths in the Aespoe Hard Rock Laboratory (HRL). Matrix pore fluids/waters can be highly saline in composition and, if accessible, may influence the near-field groundwater chemistry of a repository system. Characterising pore fluids/waters involved in-situ borehole sampling and analysis integrated with laboratory studies and experiments on rock matrix drill core material. Relating the rate of in-situ pore water accumulation during sampling to the measured rock porosity indicated a hydraulic conductivity of 10{sup -14}-10{sup -13} m/s for the rock matrix. This was in accordance with earlier estimated predictions. The sampled matrix pore water, brackish in type, mostly represents older palaeo- groundwater mixtures preserved in the rock matrix and dating back to at least the last glaciation. A component of matrix pore 'fluid' is also present. One borehole section suggests a younger groundwater component which has accessed the rock matrix during the experiment. There is little evidence that the salinity of the matrix pore waters has been influenced significantly by fluid inclusion populations hosted by quartz. Crush/leach, cation exchange, pore water diffusion and pore water displacement laboratory experiments were carried out to compare extracted/calculated matrix pore fluids/waters with in-situ sampling. Of these the pore water diffusion experiments appear to be the most promising approach and a recommended site characterisation protocol has been formulated. The main conclusions from the Matrix Fluid Chemistry Experiment are: Groundwater movement within the bedrock hosting the experimental site has been enhanced by increased hydraulic gradients generated by the presence of the tunnel, and to a much lesser extent by the borehole itself. Over experimental timescales {approx}4 years) solute transport

  9. Voltage and current spectra for matrix power converters

    OpenAIRE

    Cox, Stephen M.; Creagh, Stephen C.

    2009-01-01

    Matrix power converters are used for transforming one alternating-current power supply to another, with different peak voltage and frequency. There are three input lines, with sinusoidally varying voltages which are 120◦ out of phase one from another, and the output is to be delivered as a similar three-phase supply. The matrix converter switches rapidly, to connect each output line in sequence to each of the input lines in an attempt to synthesize the prescribed output voltages. The switchin...

  10. Matrix Integrals and Feynman Diagrams in the Kontsevich Model

    OpenAIRE

    Fiorenza, Domenico; Murri, Riccardo

    2003-01-01

    We review some relations occurring between the combinatorial intersection theory on the moduli spaces of stable curves and the asymptotic behavior of the 't Hooft-Kontsevich matrix integrals. In particular, we give an alternative proof of the Witten-Di~Francesco-Itzykson-Zuber theorem ---which expresses derivatives of the partition function of intersection numbers as matrix integrals--- using techniques based on diagrammatic calculus and combinatorial relations among inte...

  11. Ceramic Hosts for Fission Products Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Peter C Kong

    2010-07-01

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  12. Ceramic Hosts for Fission Products Immobilization

    International Nuclear Information System (INIS)

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  13. Fungal sensing of host environment.

    Science.gov (United States)

    Braunsdorf, C; Mailänder-Sánchez, D; Schaller, M

    2016-09-01

    To survive inside a host, fungi have to adapt to a changing and often hostile environment and therefore need the ability to recognize what is going on around them. To adapt to different host niches, they need to sense external conditions such as temperature, pH and to recognize specific host factors. The ability to respond to physiological changes inside the host, independent of being in a commensal, pathogenic or even symbiotic context, implicates mechanisms for sensing of specific host factors. Because the cell wall is constantly in contact with the surrounding, fungi express receptors on the surface of their cell wall, such as pheromone receptors, which have important roles, besides mediating chemotropism for mating. We are not restricting the discussion to the human host because the receptors and mechanisms used by different fungal species to sense their environment are often similar even for plant pathogens. Furthermore, the natural habitat of opportunistic pathogenic fungi with the potential to cause infection in a human host is in soil and on plants. While the hosts' mechanisms of sensing fungal pathogens have been addressed in the literature, the focus of this review is to fill the gap, giving an overview on fungal sensing of a host-(ile) environment. Expanding our knowledge on host-fungal interactions is extremely important to prevent and treat diseases of pathogenic fungi, which are important issues in human health and agriculture but also to understand the delicate balance of fungal symbionts in our ecosystem. PMID:27155351

  14. Matrix model holography

    OpenAIRE

    Ortiz, Thomas; Samtleben, Henning; Tsimpis, Dimitrios

    2014-01-01

    We set up the formalism of holographic renormalization for the matter-coupled two-dimensional maximal supergravity that captures the low-lying fluctuations around the non-conformal D0-brane near-horizon geometry. As an application we compute holographically one- and two-point functions of the BFSS matrix quantum mechanics and its supersymmetric $SO(3)\\times SO(6)$ deformation.

  15. Event matrix system

    International Nuclear Information System (INIS)

    The number of background events in nuclear and particle physics experiments which use multiwire proportional chambers can be extremely high. Using a computer to resolve these events results in a high deadtime for the experiment. A fast matrix system for decreasing the number of background events is described in this report. 4 figures

  16. Matrix Synthesis and Characterization

    Science.gov (United States)

    1984-01-01

    The role of NASA in the area of composite material synthesis; evaluation techniques; prediction analysis techniques; solvent-resistant tough composite matrix; resistance to paint strippers; acceptable processing temperature and pressure for thermoplastics; and the role of computer modeling and fiber interface improvement were discussed.

  17. Lack of Host Specialization on Winter Annual Grasses in the Fungal Seed Bank Pathogen Pyrenophora semeniperda.

    Science.gov (United States)

    Beckstead, Julie; Meyer, Susan E; Ishizuka, Toby S; McEvoy, Kelsey M; Coleman, Craig E

    2016-01-01

    Generalist plant pathogens may have wide host ranges, but many exhibit varying degrees of host specialization, with multiple pathogen races that have narrower host ranges. These races are often genetically distinct, with each race causing highest disease incidence on its host of origin. We examined host specialization in the seed pathogen Pyrenophora semeniperda by reciprocally inoculating pathogen strains from Bromus tectorum and from four other winter annual grass weeds (Bromus diandrus, Bromus rubens, Bromus arvensis and Taeniatherum caput-medusae) onto dormant seeds of B. tectorum and each alternate host. We found that host species varied in resistance and pathogen strains varied in aggressiveness, but there was no evidence for host specialization. Most variation in aggressiveness was among strains within populations and was expressed similarly on both hosts, resulting in a positive correlation between strain-level disease incidence on B. tectorum and on the alternate host. In spite of this lack of host specialization, we detected weak but significant population genetic structure as a function of host species using two neutral marker systems that yielded similar results. This genetic structure is most likely due to founder effects, as the pathogen is known to be dispersed with host seeds. All host species were highly susceptible to their own pathogen races. Tolerance to infection (i.e., the ability to germinate even when infected and thereby avoid seed mortality) increased as a function of seed germination rate, which in turn increased as dormancy was lost. Pyrenophora semeniperda apparently does not require host specialization to fully exploit these winter annual grass species, which share many life history features that make them ideal hosts for this pathogen. PMID:26950931

  18. A Fungal Endosymbiont Affects Host Plant Recruitment Through Seed- and Litter-mediated Mechanisms

    Science.gov (United States)

    1. Many grass species are associated with maternally transmitted fungal endophytes. Increasing evidence shows that endophytes enhance host plant success under varied conditions, yet studies have rarely considered alternative mechanisms whereby these mutualistic symbionts may affect regeneration from...

  19. The evolution of host specialisation in avian brood parasites.

    Science.gov (United States)

    Medina, Iliana; Langmore, Naomi E

    2016-09-01

    Traditional ecological theory predicts that specialisation can promote speciation; hence, recently derived species are specialists. However, an alternative view is that new species have broad niches, which become narrower and specialised over time. Here, we test these hypotheses using avian brood parasites and three different measures of host specialisation. Brood parasites provide an ideal system in which to investigate the evolution of specialisation, because some exploit more than 40 host species and others specialise on only one. We find that young brood parasite species are smaller and specialise on a narrower range of host sizes, as expected, if specialisation is linked with the generation of new species. Moreover, we show that highly virulent parasites are more specialised, supporting findings in other host-parasite systems. Finally, we demonstrate that different measures of specialisation can lead to different conclusions, and specialisation indices should be designed taking into account the biology of each system. PMID:27417381

  20. Characterization of resonances using an exact model S-matrix

    Energy Technology Data Exchange (ETDEWEB)

    Yamani, H.A.; Abdelmonem, M.S. [Dept. of Phys., King Fahd Univ. of Pet. and Miner., Dhahran (Saudi Arabia)

    1995-05-07

    The S-matrix, which is exact for a model potential that can be made to closely approximate a given physical potential, is found in closed form as a function of complex system energy. This allows a calculation of the density of resonance states for real scattering energies, from which real resonance position, total widths, and partial widths can easily be extracted. Alternatively, a direct search of the poles of the S-matrix in the complex energy plane locates the complex resonance energies while the residues of the S-matrix elements at each pole yield the resonance partial widths. (author)

  1. Communication: Generalized canonical purification for density matrix minimization

    Science.gov (United States)

    Truflandier, Lionel A.; Dianzinga, Rivo M.; Bowler, David R.

    2016-03-01

    A Lagrangian formulation for the constrained search for the N-representable one-particle density matrix based on the McWeeny idempotency error minimization is proposed, which converges systematically to the ground state. A closed form of the canonical purification is derived for which no a posteriori adjustment on the trace of the density matrix is needed. The relationship with comparable methods is discussed, showing their possible generalization through the hole-particle duality. The appealing simplicity of this self-consistent recursion relation along with its low computational complexity could prove useful as an alternative to diagonalization in solving dense and sparse matrix eigenvalue problems.

  2. r-BlockPermutation Factor Circulant Matrix and Inverse Matrix

    OpenAIRE

    SUN Ji zhong; QIN Keyun; Hu, Yan

    2012-01-01

    The concept of r-block permutation factor circulant matrix is presented. The characteristics of r-block permutation factor circulant matrix are discussed by Kronecker. The interchange ability of r-block permutation factor circulant matrix has been demonstrated, that is AB=BA. The calculation method of matrix determinant and the sufficient condition of nonsingular matrix based on the diagonalization of circulant matrices are given. Finally, the method of inverse matrix is given in r-blo...

  3. Host City Contract operational requirements

    OpenAIRE

    2015-01-01

    The Host City Contract - Operational Requirements (the “HCC Operational Requirements”) are an important part of the Host City Contract, detailing a set of core elements for the project, which provide Olympic quality conditions for the athletes and all participants, while at the same time allowing potential host cities to responsibly match their Games concepts to their own sport, economic, social, and environmental long-term planning needs.

  4. Aluminium matrix composites fabricated by infiltration method

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2009-03-01

    Full Text Available Purpose: The aim of this work is to examine the structure and properties of metal matrix composites obtained by infiltration method of porous ceramic preforms by liquid aluminium alloy.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of ceramic powder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the pore forming the carbon fibers Sigrafil C10 M250 UNS were used. Then ceramic preforms were infiltrated with liquid eutectic EN AC – AlSi12 aluminum alloy. Stereological and structure investigations of obtained composite materials were made on light microscope. The mechanical properties of obtained composite material were investigated in tensile strength test and hardness test.Findings: It was proved that developed technology of manufacturing of composite materials based on the porous ceramic Al2O3 preforms infiltrated by liquid aluminium alloy ensures expected structure and strength Hardness increased about twice compared to the matrix and this process can be used in practice.Practical implications: The presented metal matrix composites fabrication technology allows to obtain locally reinforced elements and near net shape products.Originality/value: Results show the possibility of obtaining the new aluminium matrix composite materials being the cheaper alternative for other materials based on the ceramic fibers.

  5. Deposition of matrix-free fullerene films with improved morphology by matrix-assisted pulsed laser evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Canulescu, Stela; Schou, Jørgen; Fæster, Søren;

    2013-01-01

    Thin films of C60 were deposited by matrix-assisted pulsed laser evaporation (MAPLE) from a frozen target of anisole with 0.67 wt% C60. Above a fluence of 1.5 J/cm2 the C60 films are strongly non-uniform and are resulting from transfer of matrix-droplets containing fullerenes. At low fluence the...... fullerene molecules in the films are intact, the surface morphology is substantially improved and there are no measurable traces of the matrix molecules in the film. This may indicate a regime of dominant evaporation at low fluence which merges into the MAPLE regime of liquid ejection of the host matrix at...

  6. A nonsupersymmetric matrix orbifold

    CERN Document Server

    Banks, T; Banks, Tom; Motl, Lubos

    2000-01-01

    We construct the matrix description for a twisted version of the IIA string theory on S^1 with fermions antiperiodic around a spatial circle. The result is a 2+1-dimensional U(N) x U(N) nonsupersymmetric Yang-Mills theory with fermionic matter transforming in the (N,Nbar). The two U(N)'s are exchanged if one goes around a twisted circle of the worldvolume. Relations with Type 0 theories are explored and we find Type 0 matrix string limits of our gauge theory. We argue however that most of these results are falsified by the absence of SUSY nonrenormalization theorems and that the models do not in fact have a sensible Lorentz invariant space time interpretation.

  7. XRF matrix corrections

    International Nuclear Information System (INIS)

    Full text: In order to obtain meaningful analytical information from an X-Ray Fluorescence spectrometer, it is necessary to correlate measured intensity values with sample concentrations. The ability to do this to a desired level of precision depends on taking care of a number of variables which influence measured intensity values. These variables include: the sample, which needs to be homogeneous, flat and critically thick to the analyte lines used for measurement; the spectrometer, which needs to perform any mechanical movements in a highly reproducible manner; the time taken to measure an analyte line, and the software, which needs to take care of detector dead-time, the contribution of background to the measured signal, the effects of line overlaps and matrix (absorption and enhancement) effects. This presentation will address commonly used correction procedures for matrix effects and their relative success in achieving their objective. Copyright (2002) Australian X-ray Analytical Association Inc

  8. Paths correlation matrix.

    Science.gov (United States)

    Qian, Weixian; Zhou, Xiaojun; Lu, Yingcheng; Xu, Jiang

    2015-09-15

    Both the Jones and Mueller matrices encounter difficulties when physically modeling mixed materials or rough surfaces due to the complexity of light-matter interactions. To address these issues, we derived a matrix called the paths correlation matrix (PCM), which is a probabilistic mixture of Jones matrices of every light propagation path. Because PCM is related to actual light propagation paths, it is well suited for physical modeling. Experiments were performed, and the reflection PCM of a mixture of polypropylene and graphite was measured. The PCM of the mixed sample was accurately decomposed into pure polypropylene's single reflection, pure graphite's single reflection, and depolarization caused by multiple reflections, which is consistent with the theoretical derivation. Reflection parameters of rough surface can be calculated from PCM decomposition, and the results fit well with the theoretical calculations provided by the Fresnel equations. These theoretical and experimental analyses verify that PCM is an efficient way to physically model light-matter interactions. PMID:26371930

  9. Extended Matrix Variate Hypergeometric Functions and Matrix Variate Distributions

    OpenAIRE

    Daya K. Nagar; Raúl Alejandro Morán-Vásquez; Gupta, Arjun K.

    2015-01-01

    Hypergeometric functions of matrix arguments occur frequently in multivariate statistical analysis. In this paper, we define and study extended forms of Gauss and confluent hypergeometric functions of matrix arguments and show that they occur naturally in statistical distribution theory.

  10. [Tuberculosis in compromised hosts].

    Science.gov (United States)

    2003-11-01

    Recent development of tuberculosis in Japan tends to converge on a specific high risk group. The proportion of tuberculosis developing particularly from the compromised hosts in the high risk group is especially high. At this symposium, therefore, we took up diabetes mellitus, gastrectomy, dialysis, AIDS and the elderly for discussion. Many new findings and useful reports for practical medical treatment are submitted; why these compromised hosts are predisposed to tuberculosis, tuberculosis diagnostic and remedial notes of those compromised hosts etc. It is an important question for the future to study how to prevent tuberculosis from these compromised hosts. 1. Tuberculosis in diabetes mellitus: aggravation and its immunological mechanism: Kazuyoshi KAWAKAMI (Department of Internal Medicine, Division of Infectious Diseases, Graduate School and Faculty of Medicine, University of the Ryukyus). It has been well documented that diabetes mellitus (DM) is a major aggravating factor in tuberculosis. The onset of this disease is more frequent in DM patients than in individuals with any underlying diseases. However, the precise mechanism of this finding remains to be fully understood. Earlier studies reported that the migration, phagocytosis and bactericidal activity of neutrophils are all impaired in DM patients, which is related to their reduced host defense to infection with extracellular bacteria, such as S. aureus and E. colli. Host defense to mycobacterial infection is largely mediated by cellular immunity, and Th1-related cytokines, such as IFN-gamma and IL-12, play a central role in this response. It is reported that serum level of these cytokines and their production by peripheral blood mononuclear cells (PBMC) are reduced in tuberculosis patients with DM, and this is supposed to be involved in the high incidence of tuberculosis in DM. Our study observed similar findings and furthermore indicated that IFN-gamma and IL-12 production by BCG-stimulated PBMC was lower

  11. Numerical matrix method for quantum periodic potentials

    Science.gov (United States)

    Le Vot, Felipe; Meléndez, Juan J.; Yuste, Santos B.

    2016-06-01

    A numerical matrix methodology is applied to quantum problems with periodic potentials. The procedure consists essentially in replacing the true potential by an alternative one, restricted by an infinite square well, and in expressing the wave functions as finite superpositions of eigenfunctions of the infinite well. A matrix eigenvalue equation then yields the energy levels of the periodic potential within an acceptable accuracy. The methodology has been successfully used to deal with problems based on the well-known Kronig-Penney (KP) model. Besides the original model, these problems are a dimerized KP solid, a KP solid containing a surface, and a KP solid under an external field. A short list of additional problems that can be solved with this procedure is presented.

  12. Inside the NIKE matrix

    OpenAIRE

    BRENNER, BARBARA; Bodo B. Schlegelmilch; Ambos, Björn

    2013-01-01

    This case describes how Nike, a consumer goods company with an ever expanding portfolio and a tremendous brand value, manages the tradeoff between local responsiveness and global integration. In particular, the case highlights Nike's organizational structure that consists of a global matrix organization that is replicated at a regional level for the European market. While this organizational structure allows Nike to respond to local consumer tastes it also ensures that the company benefits f...

  13. Infinite matrix products and the representation the gamma matrix function

    OpenAIRE

    J.-C. Cortés; Jódar, L.; Francisco J. Solís; Roberto Ku-Carrillo

    2015-01-01

    We introduce infinite matrix products including some of their main properties and convergence results. We apply them in order to extend to the matrix scenario the definition of the scalar gamma function given by an infinite product due to Weierstrass. A limit representation of the matrix gamma function is also provided.

  14. The host model Galleria mellonella is resistant to taylorellae infection.

    Science.gov (United States)

    Hébert, L; Rincé, I; Sanna, C; Laugier, C; Rincé, A; Petry, S

    2014-10-01

    The genus Taylorella is composed of two species: (i) Taylorella equigenitalis, the causative agent of CEM, a venereally transmitted infection of Equidae and (ii) Taylorella asinigenitalis, a closely related species considered to be nonpathogenic, although experimental infection of mares with this bacterium resulted in clinical signs of vaginitis, cervicitis or endometritis. Currently, there is a need for an alternative host model to further study the taylorellae species. In this context, we explored Galleria mellonella larvae as potential alternative model hosts for taylorellae. Our results showed that infection of G. mellonella larvae with a high concentration of taylorellae did not induce overt G. mellonella mortality and that taylorellae were not able to proliferate within G. mellonella. In conclusion, G. mellonella larvae are resistant to taylorellae infection and therefore do not constitute a relevant alternative system for studying the virulence of taylorellae species. Significance and impact of the study: To date, the pathogenicity and host colonization capacity of Taylorella equigenitalis, the causative agent of contagious equine metritis (CEM) and T. asinigenitalis, the second species within the Taylorella genus, remain largely unknown. In this study, we evaluated the relevance of Galleria mellonella as an infection model for taylorellae; we showed that G. mellonella are resistant to taylorellae infection and therefore do not constitute a suitable host model for taylorellae. PMID:24945970

  15. Physiological vs. ecological host range

    Science.gov (United States)

    The mantra in biological control using microbial agents is safety. Host specific organisms are safe to use as biological control agents. Although host specific organisms are known for many targets, candidate agents must be tested to clearly understand and confirm this as a property of the organism...

  16. Experimental study of kinetic and mechanism of dissolution of apatite structured minerals. Application to the prediction of the long term behavior of an actinides storage host matrix; Etude experimentale de la cinetique et des mecanismes d'alteration de mineraux apatitiques. Application au comportement d'une ceramique de confinement d'actinides mineurs

    Energy Technology Data Exchange (ETDEWEB)

    Chairat, C

    2005-11-15

    The motivation for this study is to assess the potential of using apatite structured ceramics as long-lived actinide storage hosts. To assess their ability to resist aqueous corrosion, the dissolution of natural fluoro-apatite and synthetic Nd-britholite (neodymium is a proxy for the trivalent actinides) was studied. Mineral surfaces were characterized using a combined spectrometric, electrokinetic and potentiometric approach and dissolution rates were measured in closed and open system reactors as a function of solution composition. Experimental results suggest apatitic minerals dissolve via distinct step sequence: 1) fluoride release, 2) release of the calcium situated in the M1, and 3) the simultaneous removal of phosphate and calcium II via the breaking of only Ca-O bonds. TST based rate equations based in this mechanism accurately describe fluoro-apatite and synthetic britholite dissolution rates as a function of solution composition. Nd release rates are limited by precipitation of Nd-rhabdophane. (author)

  17. Host state incentives and compensation:

    International Nuclear Information System (INIS)

    After reviewing several options for selecting a host state, the Commission elected to proceed with anoption that builds upon developing grass-roots acceptance and support. To foster such support the Commission has adopted an incentives and compensation package. The purpose of the package is that the incentives and compensations offered are designed to encourage an objective and unbiased review of accepting the responsibilities of a host state or community, and the package helps to guarantee that a facility will become a state/community asset and not impose economic, environmenta, or social hardships for the host community. This report, which describes the Commission's host state incentive and compensation package, the monetary benefit to the host community and state will be substantial. Community benefits will exceed $40 million over 20 years and benefits to the state will be approximately $24 million over the 20-year expected life of the facility. 10 refs., 4 tabs

  18. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    transmission to their bird definitive host by predation. In experimental infections, we found an intensity-dependent establishment success, with a decrease in the success rate of cercariae developing into infective metacercariae with an increasing dose of cercariae applied to each amphipod. In natural......Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer a...... reduction in size, caused by crowding, virtually nothing is known about longer-lasting effects after transmission to the definitive host. This study is the first to use in vitro cultivation with feeding of adult trematodes to investigate how numbers of parasites in the intermediate host affect the size and...

  19. Matrix Completions and Chordal Graphs

    Institute of Scientific and Technical Information of China (English)

    Kenneth John HARRISON

    2003-01-01

    In a matrix-completion problem the aim is to specifiy the missing entries of a matrix inorder to produce a matrix with particular properties. In this paper we survey results concerning matrix-completion problems where we look for completions of various types for partial matrices supported ona given pattern. We see that thc existence of completions of the required type often depends on thechordal properties of graphs associated with the pattern.

  20. Drug Discovery of Host CLK1 Inhibitors for Influenza Treatment

    OpenAIRE

    Mian Zu; Chao Li; Jian-Song Fang; Wen-Wen Lian; Ai-Lin Liu; Li-Shu Zheng; Guan-Hua Du

    2015-01-01

    The rapid evolution of influenza virus makes antiviral drugs less effective, which is considered to be a major bottleneck in antiviral therapy. The key proteins in the host cells, which are related with the replication cycle of influenza virus, are regarded as potential drug targets due to their distinct advantage of lack of evolution and drug resistance. Cdc2-like kinase 1 (CLK1) in the host cells is responsible for alternative splicing of the M2 gene of influenza virus during influenza infe...

  1. Complementary and Alternative Medicine

    Science.gov (United States)

    ... Help a Friend Who Cuts? Complementary and Alternative Medicine KidsHealth > For Teens > Complementary and Alternative Medicine Print ... replacement. continue How Is CAM Different From Conventional Medicine? Conventional medicine is based on scientific knowledge of ...

  2. The cellulose resource matrix.

    Science.gov (United States)

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  3. Phenomenological approach to symmetry breaking pattern of democratic mass matrix

    CERN Document Server

    Harada, J

    2002-01-01

    We investigate the symmetry breaking pattern of the democratic mass matrix model, which leads to the small flavor mixing in quark sector and bi-large mixing in lepton sector. We present the symmetry breaking matrices in quark sector which are determined by alternative ways instead of conventional ansatz. These matrices might be useful for understanding the origin of democratic symmetry and its breaking.

  4. Matrix vector analysis

    CERN Document Server

    Eisenman, Richard L

    2005-01-01

    This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur

  5. Investigating Boolean Matrix Factorization

    Czech Academy of Sciences Publication Activity Database

    Snášel, V.; Platoš, J.; Krömer, P.; Húsek, Dušan; Neruda, Roman; Frolov, A. A.

    - : ACM, 2008 - (Ding, C.; Li, T.; Zhu, S.), s. 18-25 ISBN 978-1-60558-307-5. [DMMT'08. Workshop in Conjunction with SIGKDD 2008 /14./. Las Vegas (US), 24.08.2008-24.08.2008] Institutional research plan: CEZ:AV0Z10300504 Keywords : Boolean factor analysis * nonnegative matrix factorization * neural networks * information retrieval * data mining * binary data Subject RIV: BB - Applied Statistics, Operational Research http://users.cs.fiu.edu/~taoli/kdd08-workshop/DMMT08-Proceedings.pdf

  6. Matrix string partition function

    CERN Document Server

    Kostov, Ivan K; Kostov, Ivan K.; Vanhove, Pierre

    1998-01-01

    We evaluate quasiclassically the Ramond partition function of Euclidean D=10 U(N) super Yang-Mills theory reduced to a two-dimensional torus. The result can be interpreted in terms of free strings wrapping the space-time torus, as expected from the point of view of Matrix string theory. We demonstrate that, when extrapolated to the ultraviolet limit (small area of the torus), the quasiclassical expressions reproduce exactly the recently obtained expression for the partition of the completely reduced SYM theory, including the overall numerical factor. This is an evidence that our quasiclassical calculation might be exact.

  7. Guest-host interactions between dichroic dyes and anisotropic hosts

    International Nuclear Information System (INIS)

    The guest-host interaction between dichroic dyes and anistropic hosts has been investigated by means of optical spectroscopy. Two different TCNQ adducts; 2-{4-[(2,6-dimethylmorpholin-4-yl)(4-metylpiperidin-1-yl) methylene]cyclohexa-2,5-dien-1-ylidene} malononitrile (MORPIP) and 2-{4-[cyclohex-1-yltetrahydropyrimidin-2(1H-ylidene] cyclohexa-2,5-dien-1-ylidine} malononitrile (AMINO) have been examined dispersed in a range of nematic liquid crystal mixtures. The result is a substantial impact on the absorption and luminescence when compared to the situation in isotropic solvents. The excited state decay exhibits a complex behaviour showing a multi-exponential decay of the time-resolved luminescence. The photoluminescence quantum yields of the chromophores, also shows strong host dependence. For AMINO, we observe a trend which is indicative of a viscosity dependence. The observations are discussed in view of different solvent-solute interactions between guest and host

  8. Towards host-to-host meeting scheduling negotiation

    Directory of Open Access Journals (Sweden)

    Rani Megasari

    2015-03-01

    Full Text Available This paper presents a different scheme of meeting scheduling negotiation among a large number of personnel in a heterogeneous community. This scheme, named Host-to-Host Negotiation, attempts to produce a stable schedule under uncertain personnel preferences. By collecting information from hosts’ inter organizational meeting, this study intends to guarantee personnel availability. As a consequence, personnel’s and meeting’s profile in this scheme are stored in a centralized manner. This study considers personnel preferences by adapting the Clarke Tax Mechanism, which is categorized as a non manipulated mechanism design. Finally, this paper introduces negotiation strategies based on the conflict handling mode. A host-to-host scheme can give notification if any conflict exist and lead to negotiation process with acceptable disclosed information. Nevertheless, a complete negotiation process will be more elaborated in the future works.

  9. Matrix algebra for linear models

    CERN Document Server

    Gruber, Marvin H J

    2013-01-01

    Matrix methods have evolved from a tool for expressing statistical problems to an indispensable part of the development, understanding, and use of various types of complex statistical analyses. This evolution has made matrix methods a vital part of statistical education. Traditionally, matrix methods are taught in courses on everything from regression analysis to stochastic processes, thus creating a fractured view of the topic. Matrix Algebra for Linear Models offers readers a unique, unified view of matrix analysis theory (where and when necessary), methods, and their applications. Written f

  10. Hierarchical Matrix Techniques on Massively Parallel Computers

    OpenAIRE

    Izadi, Mohammad

    2012-01-01

    Hierarchical matrix (H-matrix) techniques can be used to efficiently treat dense matrices. With an H-matrix, the storage requirements and performing all fundamental operations, namely matrix-vector multiplication, matrix-matrix multiplication and matrix inversion can be done in almost linear complexity. In this work, we tried to gain even further speedup for the H-matrix arithmetic by utilizing multiple processors. Our approach towards an H-matrix distribution relies on the s...

  11. Regulation of the Host Antiviral State by Intercellular Communications

    Directory of Open Access Journals (Sweden)

    Sonia Assil

    2015-08-01

    Full Text Available Viruses usually induce a profound remodeling of host cells, including the usurpation of host machinery to support their replication and production of virions to invade new cells. Nonetheless, recognition of viruses by the host often triggers innate immune signaling, preventing viral spread and modulating the function of immune cells. It conventionally occurs through production of antiviral factors and cytokines by infected cells. Virtually all viruses have evolved mechanisms to blunt such responses. Importantly, it is becoming increasingly recognized that infected cells also transmit signals to regulate innate immunity in uninfected neighboring cells. These alternative pathways are notably mediated by vesicular secretion of various virus- and host-derived products (miRNAs, RNAs, and proteins and non-infectious viral particles. In this review, we focus on these newly-described modes of cell-to-cell communications and their impact on neighboring cell functions. The reception of these signals can have anti- and pro-viral impacts, as well as more complex effects in the host such as oncogenesis and inflammation. Therefore, these “broadcasting” functions, which might be tuned by an arms race involving selective evolution driven by either the host or the virus, constitute novel and original regulations of viral infection, either highly localized or systemic.

  12. Characterization of supercapacitors matrix

    International Nuclear Information System (INIS)

    This paper treats supercapacitors matrix characterization. In order to cut off transient power peaks and to compensate for the intrinsic limitations in embedded sources, the use of supercapacitors as a storage system is quite suitable, because of their appropriate electrical characteristics (huge capacitance, small series resistance, high specific energy, high specific power), direct storage (energy ready for use), and easy control by power electronic conversion. This use requires supercapacitors modules where several cells connected in serial and/or in parallel, thus a bypass system to balance the charging or the discharging of supercapacitors is required. In the matrix of supercapacitors, six elements of three parallel BCAP0350 supercapacitors in serial connections have been considered. This topology permits to reduce the number of the bypass circuits and it can work in degraded mode. Actually, it allows the system to have more reliability by providing power continually to the load even when there are one or more cells failed. Simulation and experimental results are presented and discussed.

  13. Design of Linear Systolic Arrays for Matrix Multiplication

    OpenAIRE

    MILOVANOVIC, E. I.; STOJCEV, M. K.; MILOVANOVIC, I. Z.; NIKOLIC, T. R.

    2014-01-01

    This paper presents architecture for matrix multiplication optimized to be integrated as an accelerator unit to a host computer. Two linear systolic arrays with unidirectional data flow (ULSA), used as hardware accelerators, where synthesized in this paper. The solution proposed here is designed to accelerate both the computation and communication by employing hardware address generator units (AGUs). The proposed design has been implemented on Xilinx Spartan-2E and Virtex4 FPG...

  14. Association of Ebola Virus Matrix Protein VP40 with Microtubules

    OpenAIRE

    Ruthel, Gordon; Demmin, Gretchen L.; Kallstrom, George; Javid, Melodi P.; Badie, Shirin S.; Will, Amy B.; Nelle, Timothy; Schokman, Rowena; Nguyen, Tam L.; Carra, John H; Bavari, Sina; Aman, M. Javad

    2005-01-01

    Viruses exploit a variety of cellular components to complete their life cycles, and it has become increasingly clear that use of host cell microtubules is a vital part of the infection process for many viruses. A variety of viral proteins have been identified that interact with microtubules, either directly or via a microtubule-associated motor protein. Here, we report that Ebola virus associates with microtubules via the matrix protein VP40. When transfected into mammalian cells, a fraction ...

  15. Structure of Equine Infectious Anemia Virus Matrix Protein

    OpenAIRE

    Hatanaka, Hideki; Iourin, Oleg; Rao, Zihe; Fry, Elizabeth; Kingsman, Alan; Stuart, David I.

    2002-01-01

    The Gag polyprotein is key to the budding of retroviruses from host cells and is cleaved upon virion maturation, the N-terminal membrane-binding domain forming the matrix protein (MA). The 2.8-Å resolution crystal structure of MA of equine infectious anemia virus (EIAV), a lentivirus, reveals that, despite showing no sequence similarity, more than half of the molecule can be superimposed on the MAs of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV). However...

  16. Hosts and parasites as aliens.

    Science.gov (United States)

    Taraschewski, H

    2006-06-01

    Over the past decades, various free-living animals (hosts) and their parasites have invaded recipient areas in which they had not previously occurred, thus gaining the status of aliens or exotics. In general this happened to a low extent for hundreds of years. With variable frequency, invasions have been followed by the dispersal and establishment of non-indigenous species, whether host or parasite. In the literature thus far, colonizations by both hosts and parasites have not been treated and reviewed together, although both are usually interwoven in various ways. As to those factors permitting invasive success and colonization strength, various hypotheses have been put forward depending on the scientific background of respective authors and on the conspicuousness of certain invasions. Researchers who have tried to analyse characteristic developmental patterns, the speed of dispersal or the degree of genetic divergence in populations of alien species have come to different conclusions. Among parasitologists, the applied aspects of parasite invasions, such as the negative effects on economically important hosts, have long been at the centre of interest. In this contribution, invasions by hosts as well as parasites are considered comparatively, revealing many similarities and a few differences. Two helminths, the liver fluke, Fasciola hepatica, of cattle and sheep and the swimbladder nematode, Anguillicola crassus, of eels are shown to be useful as model parasites for the study of animal invasions and environmental global change. Introductions of F. hepatica have been associated with imports of cattle or other grazing animals. In various target areas, susceptible lymnaeid snails serving as intermediate hosts were either naturally present and/or were introduced from the donor continent of the parasite (Europe) and/or from other regions which were not within the original range of the parasite, partly reflecting progressive stages of a global biota change. In several

  17. Depleted uranium management alternatives

    International Nuclear Information System (INIS)

    This report evaluates two management alternatives for Department of Energy depleted uranium: continued storage as uranium hexafluoride, and conversion to uranium metal and fabrication to shielding for spent nuclear fuel containers. The results will be used to compare the costs with other alternatives, such as disposal. Cost estimates for the continued storage alternative are based on a life-cycle of 27 years through the year 2020. Cost estimates for the recycle alternative are based on existing conversion process costs and Capital costs for fabricating the containers. Additionally, the recycle alternative accounts for costs associated with intermediate product resale and secondary waste disposal for materials generated during the conversion process

  18. A Critical Evaluation of Bifidobacterial Adhesion to the Host Tissue

    Science.gov (United States)

    Westermann, Christina; Gleinser, Marita; Corr, Sinéad C.; Riedel, Christian U.

    2016-01-01

    Bifidobacteria are common inhabitants of the human gastrointestinal tract that, despite a long history of research, have not shown any pathogenic potential whatsoever. By contrast, some bifidobacteria are associated with a number of health-related benefits for the host. The reported beneficial effects of bifidobacteria include competitive exclusion of pathogens, alleviation of symptoms of irritable bowel syndrome and inflammatory bowel disease, and modulation of intestinal and systemic immune responses. Based on these effects, bifidobacteria are widely used as probiotics by pharmaceutical and dairy industries. In order to exert a beneficial effect bifidobacteria have to, at least transiently, colonize the host in a sufficient population size. Besides other criteria such as resistance to manufacturing processes and intestinal transit, potential probiotic bacteria are tested for adhesion to the host structures including intestinal epithelial cells, mucus, and extracellular matrix components. In the present review article, we summarize the current knowledge on bifidobacterial structures that mediate adhesion to host tissue and compare these to similar structures of pathogenic bacteria. This reveals that most of the adhesive structures and mechanisms involved in adhesion of bifidobacteria to host tissue are similar or even identical to those employed by pathogens to cause disease. It is thus reasonable to assume that these structures and mechanisms are equally important for commensal or probiotic bacteria and play a similar role in the beneficial effects exerted by bifidobacteria. PMID:27547201

  19. Screening for Host Factors Directly Interacting with RSV Protein: Microfluidics.

    Science.gov (United States)

    Kipper, Sarit; Avrahami, Dorit; Bajorek, Monika; Gerber, Doron

    2016-01-01

    We present a high-throughput microfluidics platform to identify novel host cell binding partners of respiratory syncytial virus (RSV) matrix (M) protein. The device consists of thousands of reaction chambers controlled by micro-mechanical valves. The microfluidic device is mated to a microarray-printed custom-made gene library. These genes are then transcribed and translated on-chip, resulting in a protein array ready for binding to RSV M protein.Even small viral proteome, such as that of RSV, presents a challenge due to the fact that viral proteins are usually multifunctional and thus their interaction with the host is complex. Protein microarrays technology allows the interrogation of protein-protein interactions, which could possibly overcome obstacles by using conventional high throughput methods. Using microfluidics platform we have identified new host interactors of M involved in various cellular pathways. A number of microfluidics based assays have already provided novel insights into the virus-host interactome, and the results have important implications for future antiviral strategies aimed at targets of viral protein interactions with the host. PMID:27464694

  20. Bacterial Plasminogen Receptors Utilize Host Plasminogen System for Effective Invasion and Dissemination

    OpenAIRE

    Sarbani Bhattacharya; Ploplis, Victoria A.; Castellino, Francis J.

    2012-01-01

    In order for invasive pathogens to migrate beyond the site of infection, host physiological barriers such as the extracellular matrix, the basement membrane, and encapsulating fibrin network must be degraded. To circumvent these impediments, proteolytic enzymes facilitate the dissemination of the microorganism. Recruitment of host proteases to the bacterial surface represents a particularly effective mechanism for enhancing invasiveness. Plasmin is a broad spectrum serine protease that degrad...

  1. Regularization in the J-matrix method of scattering revisited

    Energy Technology Data Exchange (ETDEWEB)

    Alhaidari, A.D. [Shura Council, Riyadh 11212 (Saudi Arabia)]. E-mail: haidari@mailaps.org; Bahlouli, H. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Abdelmonem, M.S. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Ameen, F. [Girls College of Sciences, Dammam 31113 (Saudi Arabia); Al-Abdulaal, T. [Girls College of Sciences, Dammam 31113 (Saudi Arabia)

    2007-05-07

    We present an alternative, but equivalent, approach to the regularization of the reference problem in the J-matrix method of scattering. After identifying the regular solution of the reference wave equation with the ''sine-like'' solution in the J-matrix approach we proceed by direct integration to find the expansion coefficients in an L{sup 2} basis set that ensures a tridiagonal representation of the reference Hamiltonian. A differential equation in the energy is then deduced for these coefficients. The second independent solution of this equation, called the ''cosine-like'' solution, is derived by requiring it to pertain to the L{sup 2} space. These requirements lead to solutions that are exactly identical to those obtained in the classical J-matrix approach. We find the present approach to be more direct and transparent than the classical differential approach of the J-matrix method.

  2. Twisted Bethe equations from a twisted S-matrix

    CERN Document Server

    Ahn, Changrim; Bombardelli, Diego; Nepomechie, Rafael I

    2010-01-01

    All-loop asymptotic Bethe equations for a 3-parameter deformation of AdS5/CFT4 have been proposed by Beisert and Roiban. We propose a Drinfeld twist of the AdS5/CFT4 S-matrix, together with c-number diagonal twists of the boundary conditions, from which we derive these Bethe equations. Although the undeformed S-matrix factorizes into a product of two su(2|2) factors, the deformed S-matrix cannot be so factored. Diagonalization of the corresponding transfer matrix requires a generalization of the conventional algebraic Bethe ansatz approach, which we first illustrate for the simpler case of the twisted su(2) principal chiral model. We also demonstrate that the same twisted Bethe equations can alternatively be derived using instead untwisted S-matrices and boundary conditions with operatorial twists.

  3. Planets, debris and their host metallicity correlations

    Science.gov (United States)

    Fletcher, Mark; Nayakshin, Sergei

    2016-06-01

    Recent observations of debris discs, believed to be made up of remnant planetesimals, brought a number of surprises. Debris disc presence does not correlate with the host star's metallicity, and may anti-correlate with the presence of gas giant planets. These observations contradict both assumptions and predictions of the highly successful Core Accretion model of planet formation. Here we explore predictions of the alternative Tidal Downsizing (TD) scenario of planet formation. In TD, small planets and planetesimal debris is made only when gas fragments, predecessors of giant planets, are tidally disrupted. We show that these disruptions are rare in discs around high metallicity stars but release more debris per disruption than their low [M/H] analogs. This predicts no simple relation between debris disc presence and host star's [M/H], as observed. A detected gas giant planet implies in TD that its predecessor fragment was not disputed, potentially explaining why DDs are less likely to be found around stars with gas giants. Less massive planets should correlate with DD presence, and sub-Saturn planets (Mp ˜ 50 M⊕) should correlate with DD presence stronger than sub-Neptunes (Mp ≲ 15 M⊕). These predicted planet-DD correlations will be diluted and weakened in observations by planetary systems' long term evolution and multi-fragment effects neglected here. Finally, although presently difficult to observe, DDs around M dwarf stars should be more prevalent than around Solar type stars.

  4. Planets, debris and their host metallicity correlations

    Science.gov (United States)

    Fletcher, Mark; Nayakshin, Sergei

    2016-09-01

    Recent observations of debris discs (DDs), believed to be made up of remnant planetesimals, brought a number of surprises. DD presence does not correlate with the host star's metallicity, and may anticorrelate with the presence of gas giant planets. These observations contradict both assumptions and predictions of the highly successful Core Accretion model of planet formation. Here, we explore predictions of the alternative tidal downsizing (TD) scenario of planet formation. In TD, small planets and planetesimal debris is made only when gas fragments, predecessors of giant planets, are tidally disrupted. We show that these disruptions are rare in discs around high-metallicity stars but release more debris per disruption than their low [M/H] analogues. This predicts no simple relation between DD presence and host star's [M/H], as observed. A detected gas giant planet implies in TD that its predecessor fragment was not disputed, potentially explaining why DDs are less likely to be found around stars with gas giants. Less massive planets should correlate with DD presence, and sub-Saturn planets (Mp ˜ 50 M⊕) should correlate with DD presence stronger than sub-Neptunes (Mp ≲ 15 M⊕). These predicted planet-DD correlations will be diluted and weakened in observations by planetary systems' long-term evolution and multifragment effects neglected here. Finally, although presently difficult to observe, DDs around M dwarf stars should be more prevalent than around Solar type stars.

  5. Derivation of the state matrix for dynamic analysis of linear homogeneous media.

    Science.gov (United States)

    Parra Martinez, Juan Pablo; Dazel, Olivier; Göransson, Peter; Cuenca, Jacques

    2016-08-01

    A method to obtain the state matrix of an arbitrary linear homogeneous medium excited by a plane wave is proposed. The approach is based on projections on the eigenspace of the governing equations matrix. It is an alternative to manually obtaining a linearly independent set of equations by combining the governing equations. The resulting matrix has been validated against previously published derivations for an anisotropic poroelastic medium. PMID:27586783

  6. Optimal Rates of Convergence for Latent Generalized Correlation Matrix Estimation in Transelliptical Distribution

    OpenAIRE

    Han, Fang; Liu, Han

    2013-01-01

    Correlation matrix plays a key role in many multivariate methods (e.g., graphical model estimation and factor analysis). The current state-of-the-art in estimating large correlation matrices focuses on the use of Pearson's sample correlation matrix. Although Pearson's sample correlation matrix enjoys various good properties under Gaussian models, its not an effective estimator when facing heavy-tail distributions with possible outliers. As a robust alternative, \\cite{han2012transelliptical} a...

  7. Universality and Non-Perturbative Definitions of 2D Quantum Gravity from Matrix Models

    OpenAIRE

    Miramontes, J. Luis; Guillen, Joaquin Sanchez

    1991-01-01

    The universality of the non-perturbative definition of Hermitian one-matrix models following the quantum, stochastic, or $d=1$-like stabilization is discussed in comparison with other procedures. We also present another alternative definition, which illustrates the need of new physical input for $d=0$ matrix models to make contact with 2D quantum gravity at the non-perturbative level.

  8. Universality and nonperturbative definitions of 2D quantum gravity from matrix models

    International Nuclear Information System (INIS)

    The universality of the nonperturbative definition of Hermitian one-matrix models following the quantum stochastic, or d = 1-like stabilization is discussed in comparison with other procedures. The authors also present another alternative definition, which illustrates the need of new physical input for d = 0 matrix models to make contact with 2D quantum gravity at the nonperturbative level

  9. Ceramic matrix and resin matrix composites - A comparison

    Science.gov (United States)

    Hurwitz, Frances I.

    1987-01-01

    The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

  10. Ceramic matrix and resin matrix composites: A comparison

    Science.gov (United States)

    Hurwitz, Frances I.

    1987-01-01

    The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

  11. Engineering microbial hosts for production of bacterial natural products.

    Science.gov (United States)

    Zhang, Mingzi M; Wang, Yajie; Ang, Ee Lui; Zhao, Huimin

    2016-08-27

    Covering up to end 2015Microbial fermentation provides an attractive alternative to chemical synthesis for the production of structurally complex natural products. In most cases, however, production titers are low and need to be improved for compound characterization and/or commercial production. Owing to advances in functional genomics and genetic engineering technologies, microbial hosts can be engineered to overproduce a desired natural product, greatly accelerating the traditionally time-consuming strain improvement process. This review covers recent developments and challenges in the engineering of native and heterologous microbial hosts for the production of bacterial natural products, focusing on the genetic tools and strategies for strain improvement. Special emphasis is placed on bioactive secondary metabolites from actinomycetes. The considerations for the choice of host systems will also be discussed in this review. PMID:27072804

  12. Light cone matrix product

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Matthew B [Los Alamos National Laboratory

    2009-01-01

    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  13. Challenging the CSCW matrix

    DEFF Research Database (Denmark)

    Jørnø, Rasmus Leth Vergmann; Gynther, Karsten; Christensen, Ove

    2014-01-01

    useful information, we question whether the axis of time and space comprising the matrix pertains to relevant defining properties of the tools, technology or learning environments to which they are applied. Subsequently we offer an example of an Adobe Connect e-learning session as an illustration of a...... an appropriate unit of analysis and that categories of such practices can be established by an axis of articulation work and an axis of the codification needed to express and coordinate knowledge and work efforts. Keywords: E-learning; distance education; synchronous; distributed; assemblages...... different approach to learning situations based on the idea that tools, technology and learning environments are media through which participants simultaneously acquire proficiency to articulate and gain a perspective in order to decode what is going on. To effectively interact online, we contend that both...

  14. Hyaluronan: A Matrix Component

    Science.gov (United States)

    Rügheimer, Louise

    2008-09-01

    The glucosaminoglycan hyaluronan is a key component of the extracellular matrix. It is a large, negatively charged molecule that can act as an ion exchange reservoir for positive ions. Hyaluronan is involved in renomedullary water handling through its water-binding capacity. In the renal medulla, the main source for hyaluronan production is the renomedullary interstitial cells. Hyaluronan synthases are found in the inner part of the plasma membrane and polymerize hyaluronan chains which are extruded into the extracellular space. Hyaluronidases are a family of enzymes involved in the degradation of hyaluronan. They have a wide range of properties, including differences in size, inhibitor sensitivities, catalytic mechanisms, substrate specificities and pH optima.

  15. A matrix big bang

    International Nuclear Information System (INIS)

    The light-like linear dilaton background represents a particularly simple time-dependent 1/2 BPS solution of critical type-IIA superstring theory in ten dimensions. Its lift to M-theory, as well as its Einstein frame metric, are singular in the sense that the geometry is geodesically incomplete and the Riemann tensor diverges along a light-like subspace of codimension one. We study this background as a model for a big bang type singularity in string theory/M-theory. We construct the dual Matrix theory description in terms of a (1+1)-d supersymmetric Yang-Mills theory on a time-dependent world-sheet given by the Milne orbifold of (1+1)-d Minkowski space. Our model provides a framework in which the physics of the singularity appears to be under control

  16. A Matrix Big Bang

    CERN Document Server

    Craps, B; Verlinde, E; Craps, Ben; Sethi, Savdeep; Verlinde, Erik

    2005-01-01

    The light-like linear dilaton background represents a particularly simple time-dependent 1/2 BPS solution of critical type IIA superstring theory in ten dimensions. Its lift to M-theory, as well as its Einstein frame metric, are singular in the sense that the geometry is geodesically incomplete and the Riemann tensor diverges along a light-like subspace of codimension one. We study this background as a model for a big bang type singularity in string theory/M-theory. We construct the dual Matrix theory description in terms of a (1+1)-d supersymmetric Yang-Mills theory on a time-dependent world-sheet given by the Milne orbifold of (1+1)-d Minkowski space. Our model provides a framework in which the physics of the singularity appears to be under control.

  17. Matrix Quantization of Turbulence

    CERN Document Server

    Floratos, Emmanuel

    2011-01-01

    Based on our recent work on Quantum Nambu Mechanics $\\cite{af2}$, we provide an explicit quantization of the Lorenz chaotic attractor through the introduction of Non-commutative phase space coordinates as Hermitian $ N \\times N $ matrices in $ R^{3}$. For the volume preserving part, they satisfy the commutation relations induced by one of the two Nambu Hamiltonians, the second one generating a unique time evolution. Dissipation is incorporated quantum mechanically in a self-consistent way having the correct classical limit without the introduction of external degrees of freedom. Due to its volume phase space contraction it violates the quantum commutation relations. We demonstrate that the Heisenberg-Nambu evolution equations for the Matrix Lorenz system develop fast decoherence to N independent Lorenz attractors. On the other hand there is a weak dissipation regime, where the quantum mechanical properties of the volume preserving non-dissipative sector survive for long times.

  18. Quasi-classical alternatives in quantum chemistry

    CERN Document Server

    Gineityte, V

    2014-01-01

    The article contains an overview of authors achievements in development of alternative quantum-chemical approaches oriented towards revival of the classical tradition of qualitative chemical thinking instead of obtaining numerical results. The above-mentioned tradition is concluded to be based mainly on principles (rules) of additivity, transferability and locality of molecular properties. Accordingly, model Hamiltonian matrices are used in the approaches under development (called quasi-classical alternatives), wherein algebraic parameters play the role of matrix elements and these are assumed to be transferable for similar atoms and/or atomic orbitals in addition. Further, passing to delocalized descriptions of electronic structures (as usual) is expected to be the main origin of difficulties seeking to formulate quasi-classical alternatives. In the framework of the canonical method of molecular orbitals (MOs), delocalization is shown to be partially avoidable by invoking a recently-suggested approach to sec...

  19. Integrating temperature-dependent life table data into a matrix projection model for Drosophila suzukii population estimation.

    Science.gov (United States)

    Wiman, Nik G; Walton, Vaughn M; Dalton, Daniel T; Anfora, Gianfranco; Burrack, Hannah J; Chiu, Joanna C; Daane, Kent M; Grassi, Alberto; Miller, Betsey; Tochen, Samantha; Wang, Xingeng; Ioriatti, Claudio

    2014-01-01

    Temperature-dependent fecundity and survival data was integrated into a matrix population model to describe relative Drosophila suzukii Matsumura (Diptera: Drosophilidae) population increase and age structure based on environmental conditions. This novel modification of the classic Leslie matrix population model is presented as a way to examine how insect populations interact with the environment, and has application as a predictor of population density. For D. suzukii, we examined model implications for pest pressure on crops. As case studies, we examined model predictions in three small fruit production regions in the United States (US) and one in Italy. These production regions have distinctly different climates. In general, patterns of adult D. suzukii trap activity broadly mimicked seasonal population levels predicted by the model using only temperature data. Age structure of estimated populations suggest that trap and fruit infestation data are of limited value and are insufficient for model validation. Thus, we suggest alternative experiments for validation. The model is advantageous in that it provides stage-specific population estimation, which can potentially guide management strategies and provide unique opportunities to simulate stage-specific management effects such as insecticide applications or the effect of biological control on a specific life-stage. The two factors that drive initiation of the model are suitable temperatures (biofix) and availability of a suitable host medium (fruit). Although there are many factors affecting population dynamics of D. suzukii in the field, temperature-dependent survival and reproduction are believed to be the main drivers for D. suzukii populations. PMID:25192013

  20. Trophic ecology, behaviour and host population dynamics in Echinococcus multilocularis transmission.

    Science.gov (United States)

    Raoul, F; Hegglin, D; Giraudoux, P

    2015-10-30

    The life cycle of the cestode Echinococcus multilocularis primarily involves canids and small mammals (rodents, lagomorphs) as definitive and intermediate hosts, respectively. Several surveys have identified marked temporal and geographical variations at different scales in the parasite's prevalence in both types of hosts, suggesting variations in the biological and ecological factors that control transmission processes. The parasite transmission from intermediate to definitive hosts is determined by the predator-prey relationship, which theoretically depends on prey population dynamics and the complex dietary response of predators to varying densities of prey species and other food items. Parasite eggs are transmitted to intermediate hosts via carnivore faeces, whose distribution in the environment is driven by the defecating behaviour of final hosts. We reviewed field-based studies that address issues related to the trophic ecology and behaviour of definitive hosts, interactions between definitive and intermediate hosts, and E. multilocularis transmission both in wild and domestic animals in rural and urban environments. Two density-dependent mechanisms control the transmission dynamics in definitive hosts: one is based on the variations in the availability of intermediate hosts, and the other is based on the variations in the density of the definitive host and its faeces. Non-linearity and the direct and delayed responses of definitive host contamination in relation to intermediate host population variations were recorded. The dietary response of the red fox was shown to be complex when abundant alternative resources were available (anthropogenic food, multiple intermediate host prey species). Micro-local hotspots of parasite transmission to intermediate hosts in a landscape, as well as areas of higher risk for human contamination in village and urban settings, may be explained by the definitive hosts' activity patterns and defecation behaviour. PMID:26276578

  1. Host size and spatiotemporal patterns mediate the coexistence of specialist parasitoids.

    Science.gov (United States)

    Pekas, Apostolos; Tena, Alejandro; Harvey, Jeffrey A; Garcia-Mari, Ferran; Frago, Enric

    2016-05-01

    Many insect parasitoids are highly specialized and thus develop on only one or a few related host species, yet some hosts are attacked by many different parasitoid species in nature. For this reason, they have been often used to examine the consequences of competitive interactions. Hosts represent limited resources for larval parasitoid development and thus one competitor usually excludes all others. Although parasitoid competition has been debated and studied over the past several decades, understanding the factors that allow for coexistence among species sharing the same host in the field remains elusive. Parasitoids may be able to coexist on the same host species if they partition host resources according to size, age, or stage, or if their dynamics vary at spatial and temporal scales. One area that has thus far received little experimental attention is if competition can alter host usage strategies in parasitoids that in the absence of competitors attack hosts of the same size in the field. Here, we test this hypothesis with two parasitoid species in the genus Aphytis, both of which are specialized on the citrus pest California red scale Aonidiella aurantii. These parasitoids prefer large scales as hosts and yet coexist in sympatry in eastern parts of Spain. Parasitoids and hosts were sampled in 12 replicated orange groves. When host exploitation by the stronger competitor, A. melinus, was high the poorer competitor, A. chrysomphali, changed its foraging strategy to prefer alternative plant substrates where it parasitized hosts of smaller size. Consequently, the inferior parasitoid species shifted both its habitat and host size as a result of competition. Our results suggest that density-dependent size-mediated asymmetric competition is the likely mechanism allowing for the coexistence of these two species, and that the use of suboptimal (small) hosts can be advantageous under conditions imposed by competition where survival in higher quality larger hosts may

  2. SHEAR WAVES IN PERIODIC WAVEGUIDE WITH ALTERNATING BOUNDARY CONDITIONS

    Directory of Open Access Journals (Sweden)

    Piliposyan D.G.

    2014-06-01

    Full Text Available The propagation of shear waves in elastic waveguide of periodic structure consisting of three different materials with alternating along the guide walls boundary conditions is investigated. Using the transfer matrix approach the problem is reduced to the solution of a block transfer matrix eigenvalue problem. Bloth the dispersion and the band gap structure analysis have been carried out numerically. It is shown that for alternating boundary conditions along the waveguide walls, by modulating the ratio of the length of the unit cell to the width of the waveguide, the minimum widths of the stop bands can be moved to the middle of the Brillouin zone

  3. Polyphase alternating codes

    CERN Document Server

    Markkanen, Markku

    2007-01-01

    This work introduces a method for constructing polyphase alternating codes in which the length of a code transmission cycle can be $p^m$ or $p-1$, where $p$ is a prime number and $m$ is a positive integer. The relevant properties leading to the construction alternating codes and the algorithm for generating alternating codes is described. Examples of all practical and some not that practical polyphase code lengths are given.

  4. Alternative Solar Indices

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, L.J.

    1980-07-01

    Possible alternative Solar Indices which could either be a perturbation from the currently defined Solar Index or possible indices based on current technologies for other media markets are discussed. An overview is given of the current project, including the logic that was utilized in defining its current structure and then alternative indices and definitions are presented and finally, recommendations are made for adopting alternative indices.

  5. On an Alternative Cosmology

    OpenAIRE

    Vankov, A.

    1998-01-01

    The suggested alternative cosmology is based on the idea of barion symmetric universe, in which our home universe is a representative of multitude of typical matter and antimatter universes. This alternative concept gives a physically reasonable explanation of all major problems of the Standard Cosmological Model. Classification Code MSC: Cosmology 524.8 Key words: standard cosmological model, alternative cosmology, barionic symmetry, typical universe, quasars, cosmic rays.

  6. Complex Alternative Splicing

    OpenAIRE

    Park, Jung Woo; Graveley, Brenton R.

    2007-01-01

    Alternative splicing is a powerful means of controlling gene expression and increasing protein diversity. Most genes express a limited number of mRNA isoforms, but there are several examples of genes that use alternative splicing to generate hundreds, thousands, and even tens of thousands of isoforms. Collectively such genes are considered to undergo complex alternative splicing. The best example is the Drosophila Down syndrome cell adhesion molecule (Dscam) gene, which can generate 38,016 is...

  7. Cellular host responses to gliomas.

    Directory of Open Access Journals (Sweden)

    Joseph Najbauer

    Full Text Available BACKGROUND: Glioblastoma multiforme (GBM is the most aggressive type of malignant primary brain tumors in adults. Molecular and genetic analysis has advanced our understanding of glioma biology, however mapping the cellular composition of the tumor microenvironment is crucial for understanding the pathology of this dreaded brain cancer. In this study we identified major cell populations attracted by glioma using orthotopic rodent models of human glioma xenografts. Marker-specific, anatomical and morphological analyses revealed a robust influx of host cells into the main tumor bed and tumor satellites. METHODOLOGY/PRINCIPAL FINDINGS: Human glioma cell lines and glioma spheroid orthotopic implants were used in rodents. In both models, the xenografts recruited large numbers of host nestin-expressing cells, which formed a 'network' with glioma. The host nestin-expressing cells appeared to originate in the subventricular zone ipsilateral to the tumor, and were clearly distinguishable from pericytes that expressed smooth muscle actin. These distinct cell populations established close physical contact in a 'pair-wise' manner and migrated together to the deeper layers of tumor satellites and gave rise to tumor vasculature. The GBM biopsy xenografts displayed two different phenotypes: (a low-generation tumors (first in vivo passage in rats were highly invasive and non-angiogenic, and host nestin-positive cells that infiltrated into these tumors displayed astrocytic or elongated bipolar morphology; (b high-generation xenografts (fifth passage had pronounced cellularity, were angiogenic with 'glomerulus-like' microvascular proliferations that contained host nestin-positive cells. Stromal cell-derived factor-1 and its receptor CXCR4 were highly expressed in and around glioma xenografts, suggesting their role in glioma progression and invasion. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a robust migration of nestin-expressing host cells to glioma, which

  8. Alternators. Experience feedback

    International Nuclear Information System (INIS)

    Study of the technical aspects of various accidents having occured on nuclear alternators operating in the French 900 MW nuclear plant unit, and the respective solutions and possibilities for application to alternators of the 1000 and 1500 MW power plants. Analysis of the accidents on CP 1 program alternators: accidents caused by vibratory fatigue (cracking of the hydraulic connection pipes of the stator winding, cracking of the hydraulic-electric connection between the stator coiling and the output terminals, cracking of the hydrogen cooler finned tubes), pollution by copper oxide of the stator winding cooling water circuit. Accidents on CP 2 alternators: accident on the shaft sealing joint, striking inside the terminal box

  9. Boost matrix converters in clean energy systems

    Science.gov (United States)

    Karaman, Ekrem

    This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.

  10. A Matrix Model for WZW

    CERN Document Server

    Dorey, Nick; Turner, Carl

    2016-01-01

    We study a U(N) gauged matrix quantum mechanics which, in the large N limit, is closely related to the chiral WZW conformal field theory. This manifests itself in two ways. First, we construct the left-moving Kac-Moody algebra from matrix degrees of freedom. Secondly, we compute the partition function of the matrix model in terms of Schur and Kostka polynomials and show that, in the large $N$ limit, it coincides with the partition function of the WZW model. This same matrix model was recently shown to describe non-Abelian quantum Hall states and the relationship to the WZW model can be understood in this framework.

  11. A matrix model for WZW

    Science.gov (United States)

    Dorey, Nick; Tong, David; Turner, Carl

    2016-08-01

    We study a U( N) gauged matrix quantum mechanics which, in the large N limit, is closely related to the chiral WZW conformal field theory. This manifests itself in two ways. First, we construct the left-moving Kac-Moody algebra from matrix degrees of freedom. Secondly, we compute the partition function of the matrix model in terms of Schur and Kostka polynomials and show that, in the large N limit, it coincides with the partition function of the WZW model. This same matrix model was recently shown to describe non-Abelian quantum Hall states and the relationship to the WZW model can be understood in this framework.

  12. Clay matrix voltammetry

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In many countries, it is planned that the long life highly radioactive nuclear spent fuel will be stored in deep argillaceous rocks. The sites selected for this purpose are anoxic and satisfy several recommendations as mechanical stability, low permeability and low redox potential. Pyrite (FeS2), iron(II) carbonate, iron(II) bearing clays and organic matter that are present in very small amounts (about 1% w:w) in soils play a major role in their reactivity and are considered today as responsible for the low redox potential values of these sites. In this communication, we describe an electrochemical technique derived from 'Salt matrix voltammetry' and allowing the almost in-situ voltammetric characterization of air-sensitive samples of soils after the only addition of the minimum humidity required for electrolytic conduction. Figure 1 shows the principle of the developed technique. It consists in the entrapment of the clay sample between a graphite working electrode and a silver counter/quasi-reference electrode. The sample was previously humidified by passing a water saturated inert gas through the electrochemical cell. The technique leads to well-defined voltammetric responses of the electro-active components of the clays. Figure 2 shows a typical voltammogram relative to a Callovo-Oxfordian argillite sample from Bure, the French place planned for the underground nuclear waste disposal. During the direct scan, one can clearly distinguish the anodic voltammetric signals for the oxidation of the iron (II) species associated with the clay and the oxidation of pyrite. The reverse scan displays a small cathodic signal for the reduction of iron (III) associated with the clay that demonstrates that the majority of the previously oxidized iron (II) species were transformed into iron (III) oxides reducible at lower potentials. When a second voltammetric cycle is performed, one can notice that the signal for iron (II

  13. Molecular fingerprinting of Helicanthus elastica (Desr.) Danser growing on five different hosts by RAPD.

    Science.gov (United States)

    Sunil Kumar, K N; Maruthi, K R; Alfarhan, A H; Rajakrishnan, R; Thomas, J

    2016-05-01

    Mistletoes are hemiparasitic plants growing on aerial parts of other host trees. Many of the mistletoes are reported to be medicinally important. The hemiparasitic nature of these plants makes their chemical composition dependent on the host on which it grows. They are shown to exhibit morphological dissimilarities also when growing on different hosts. Helicanthus elastica (Desr.) Danser (mango mistletoe) is one such less explored medicinal mistletoe found on almost every mango tree in India. Traditionally, the leaves of this plant are used for checking abortion and for removing stones in the kidney and urinary bladder while significant antioxidant and antimicrobial properties are also attributed to this species of mistletoe. The current study was undertaken to evaluate molecular differences in the genomic DNA of the plant while growing on five different host trees using four random markers employing random amplified polymorphic DNA (RAPD) followed by similarity matrix by Jaccard's coefficient and distance matrix by hierarchal clustering analysis. Similarity and distance matrix data employing just 4 random markers, separately and the pooled data as well, revealed significant difference in the genomic DNA of H. elastica growing on five different hosts. Pooled data of similarity from all the 4 primers cumulatively showed similarity between 0.256 and 0.311. Distance matrix ranged from of 0.256 to 0.281 on pooling the data from all the four primers. The result employing a minimum number of primers could conclude that genomic DNA of H. elastica differs depending upon the host on which it grows, hence the host must be considered while studying or utilizing this mistletoe for medicinal purposes. PMID:27081357

  14. An explicit solution to the matrix equation AV+BW=EV J

    Institute of Scientific and Technical Information of China (English)

    Aiguo WU; Guangren DUAN; Bin ZHOU

    2007-01-01

    In this note,the matrix equation AV+BW=EV J is considered,where E,A and B are given matrices of appropriate dimensions,J is an arbitrarily given Jordan matrix,V and W are the matrices to be determined.Firstly,a right factorization of(sE-A)-1 B is given based on the Leverriver algorithm for descriptor systems.Then based on this factorization and a proposed parametric solution,an alternative parametric solution to this matrix equation is established in terms of the R-controllability matrix of(E,A,B),the generalized symmetric operator and the observability matrix associated with the Jordan matrix J and a free parameter matrix.The proposed results provide great convenience for many analysis and design problems.Moreover,some equivalent forms are proposed.A numerical example is employed to illustrate the effect of the proposed approach.

  15. Matrix Product Operators, Matrix Product States, and ab initio Density Matrix Renormalization Group algorithms

    CERN Document Server

    Chan, Garnet Kin-Lic; Nakatani, Naoki; Li, Zhendong; White, Steven R

    2016-01-01

    Current descriptions of the ab initio DMRG algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab-initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational par...

  16. Technique for information retrieval using enhanced latent semantic analysis generating rank approximation matrix by factorizing the weighted morpheme-by-document matrix

    Science.gov (United States)

    Chew, Peter A; Bader, Brett W

    2012-10-16

    A technique for information retrieval includes parsing a corpus to identify a number of wordform instances within each document of the corpus. A weighted morpheme-by-document matrix is generated based at least in part on the number of wordform instances within each document of the corpus and based at least in part on a weighting function. The weighted morpheme-by-document matrix separately enumerates instances of stems and affixes. Additionally or alternatively, a term-by-term alignment matrix may be generated based at least in part on the number of wordform instances within each document of the corpus. At least one lower rank approximation matrix is generated by factorizing the weighted morpheme-by-document matrix and/or the term-by-term alignment matrix.

  17. Alternative Devices for Taking Insulin

    Science.gov (United States)

    ... KB). Alternate Language URL Alternative Devices for Taking Insulin Page Content On this page: What alternative devices ... the skin. [ Top ] What alternative devices for taking insulin are available? Insulin pens provide a convenient, easy- ...

  18. Host receptors for bacteriophage adsorption.

    Science.gov (United States)

    Bertozzi Silva, Juliano; Storms, Zachary; Sauvageau, Dominic

    2016-02-01

    The adsorption of bacteriophages (phages) onto host cells is, in all but a few rare cases, a sine qua non condition for the onset of the infection process. Understanding the mechanisms involved and the factors affecting it is, thus, crucial for the investigation of host-phage interactions. This review provides a survey of the phage host receptors involved in recognition and adsorption and their interactions during attachment. Comprehension of the whole infection process, starting with the adsorption step, can enable and accelerate our understanding of phage ecology and the development of phage-based technologies. To assist in this effort, we have established an open-access resource--the Phage Receptor Database (PhReD)--to serve as a repository for information on known and newly identified phage receptors. PMID:26755501

  19. Asteroseismology of Exoplanet Host Stars

    CERN Document Server

    Huber, Daniel

    2015-01-01

    Asteroseismology is among the most powerful observational tools to determine fundamental properties of stars. Space-based photometry has recently enabled the systematic detection of oscillations in exoplanet host stars, allowing a combination of asteroseismology with transit and radial-velocity measurements to characterize planetary systems. In this contribution I will review the key synergies between asteroseismology and exoplanet science such as the precise determination of radii and ages of exoplanet host stars, as well as applications of asteroseismology to measure spin-orbit inclinations in multiplanet systems and orbital eccentricities of small planets. Finally I will give a brief outlook on asteroseismic studies of exoplanet hosts with current and future space-based missions such as K2 and TESS.

  20. Brandmodstandsbidrag for alternative isoleringsmaterialer

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place

    2001-01-01

    Resume af rapport om alternative isoleringsmaterialers brandmodstandsbidrag, udarbejdet af Dansk Brandteknisk Institut under Energistyrelsens udviklingsprogram "Miljø- og arbejdsmiljøvenlig isolering"......Resume af rapport om alternative isoleringsmaterialers brandmodstandsbidrag, udarbejdet af Dansk Brandteknisk Institut under Energistyrelsens udviklingsprogram "Miljø- og arbejdsmiljøvenlig isolering"...

  1. Anvendelse af alternative isoleringsmaterialer

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place

    2003-01-01

    Resume af By og Byg Anvisning 207 om anvendelse af alternative isoleringsmaterialer, udarbejdet af Statens Byggeforskningsinstitut under udviklingsprogrammet "Miljø- og arbejdsmiljøvenlig isolering"......Resume af By og Byg Anvisning 207 om anvendelse af alternative isoleringsmaterialer, udarbejdet af Statens Byggeforskningsinstitut under udviklingsprogrammet "Miljø- og arbejdsmiljøvenlig isolering"...

  2. Interactions between Trypanosoma cruzi Secreted Proteins and Host Cell Signaling Pathways

    Science.gov (United States)

    Watanabe Costa, Renata; da Silveira, Jose F.; Bahia, Diana

    2016-01-01

    Chagas disease is one of the prevalent neglected tropical diseases, affecting at least 6–7 million individuals in Latin America. It is caused by the protozoan parasite Trypanosoma cruzi, which is transmitted to vertebrate hosts by blood-sucking insects. After infection, the parasite invades and multiplies in the myocardium, leading to acute myocarditis that kills around 5% of untreated individuals. T. cruzi secretes proteins that manipulate multiple host cell signaling pathways to promote host cell invasion. The primary secreted lysosomal peptidase in T. cruzi is cruzipain, which has been shown to modulate the host immune response. Cruzipain hinders macrophage activation during the early stages of infection by interrupting the NF-kB P65 mediated signaling pathway. This allows the parasite to survive and replicate, and may contribute to the spread of infection in acute Chagas disease. Another secreted protein P21, which is expressed in all of the developmental stages of T. cruzi, has been shown to modulate host phagocytosis signaling pathways. The parasite also secretes soluble factors that exert effects on host extracellular matrix, such as proteolytic degradation of collagens. Finally, secreted phospholipase A from T. cruzi contributes to lipid modifications on host cells and concomitantly activates the PKC signaling pathway. Here, we present a brief review of the interaction between secreted proteins from T. cruzi and the host cells, emphasizing the manipulation of host signaling pathways during invasion. PMID:27065960

  3. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Science.gov (United States)

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

    2016-01-12

    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  4. The Inflammasome in Host Defense

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2009-12-01

    Full Text Available Nod-like receptors have emerged as an important family of sensors in host defense. These receptors are expressed in macrophages, dendritic cells and monocytes and play an important role in microbial immunity. Some Nod-like receptors form the inflammasome, a protein complex that activates caspase-1 in response to several stimuli. Caspase-1 activation leads to processing and secretion of pro-inflammatory cytokines such as interleukin (IL-1β and IL-18. Here, we discuss recent advances in the inflammasome field with an emphasis on host defense. We also compare differential requirements for inflammasome activation in dendritic cells, macrophages and monocytes.

  5. Nil-clean matrix rings

    OpenAIRE

    S. Breaz; Călugăreanu, G.; Danchev, P.; Micu, T.

    2013-01-01

    We characterize the nil clean matrix rings over fields. As a by product, it is proved that the full matrix rings with coefficients in commutative nil-clean rings are nil-clean, and we obtain a complete characterization of the finite rank Abelian groups with nil clean endomorphism ring and the Abelian groups with strongly nil clean endomorphism ring, respectively.

  6. How to Study a Matrix

    Science.gov (United States)

    Jairam, Dharmananda; Kiewra, Kenneth A.; Kauffman, Douglas F.; Zhao, Ruomeng

    2012-01-01

    This study investigated how best to study a matrix. Fifty-three participants studied a matrix topically (1 column at a time), categorically (1 row at a time), or in a unified way (all at once). Results revealed that categorical and unified study produced higher: (a) performance on relationship and fact tests, (b) study material satisfaction, and…

  7. Matrix Analysis of Tracer Transport

    CERN Document Server

    Mills, Peter

    2015-01-01

    We review matrix methods as applied to tracer transport. Because tracer transport is linear, matrix methods are an ideal fit for the problem. In particular, solutions of linear, first-order systems of ordinary differential equations (ODEs) are reviewed as well as special properties of these solutions. Detailed derivations are included

  8. HostPhinder: A Phage Host Prediction Tool

    DEFF Research Database (Denmark)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell;

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within...

  9. Endodontic Periodontic Lesions and Host Modulation – Case Series

    Directory of Open Access Journals (Sweden)

    Afaf Zia

    2015-07-01

    Full Text Available Host modulation, includes inhibition of matrix metalloproteinases, blocking production of proinflammatory cytokines and inhibition of osteoclastic activity, has therapeutic value as adjunctive therapy in treating chronic periodontitis. This case series presented three patients with chief complaint of teeth mobility where endo perio involvement was diagnosed. The endo perio combined lesions generally shows the communication between pulp and periodontal tissues with the same origin of dental infection. Diagnosis in such cases is difficult and generally raising problem in the management. All of the cases were managed by non surgical endodontic therapy combined with host modulation. All local factors causing the lesion were removed. Clinical outcome after six and nine months were quite satisfactory. Combined endo perio cases are challenging to the dentists and involve multidisciplinary involvement. To manage such cases, dentists have to rely on the unconventional techniques.DOI: 10.14693/jdi.v22i1.378

  10. The host response to allogeneic and xenogeneic biological scaffold materials.

    Science.gov (United States)

    Keane, Timothy J; Badylak, Stephen F

    2015-05-01

    The clinical use of biological scaffold materials has become commonplace. Such scaffolds are composed of extracellular matrix (ECM), or components of ECM, derived from allogeneic or xenogeneic tissues. Such scaffold materials vary widely in their source tissue, processing methods and sterilization methods. The success or failure of an ECM scaffold for a given application is dependent on the host response following implantation; a response that is largely mediated by the innate immune system and which is influenced by a numerous factors, including the processing methods used in the preparation of biological scaffolds. The present paper reviews various aspects of the host response to biological scaffolds and factors that affect this response. In addition, some of the logistical, regulatory and reconstructive implications associated with the use of biological scaffolds are discussed. PMID:24668694

  11. Machining of Metal Matrix Composites

    CERN Document Server

    2012-01-01

    Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...

  12. Multivariate Matrix-Exponential Distributions

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    2010-01-01

    In this article we consider the distributions of non-negative random vectors with a joint rational Laplace transform, i.e., a fraction between two multi-dimensional polynomials. These distributions are in the univariate case known as matrix-exponential distributions, since their densities can be...... written as linear combinations of the elements in the exponential of a matrix. For this reason we shall refer to multivariate distributions with rational Laplace transform as multivariate matrix-exponential distributions (MVME). The marginal distributions of an MVME are univariate matrix......-exponential distributions. We prove a characterization that states that a distribution is an MVME distribution if and only if all non-negative, non-null linear combinations of the coordinates have a univariate matrix-exponential distribution. This theorem is analog to a well-known characterization theorem for the...

  13. Leptospira spp.: Novel insights into host-pathogen interactions.

    Science.gov (United States)

    Fernandes, Luis G; Siqueira, Gabriela H; Teixeira, Aline R F; Silva, Lucas P; Figueredo, Jupciana M; Cosate, Maria R; Vieira, Monica L; Nascimento, Ana L T O

    2016-08-01

    Leptospirosis is a widespread zoonosis caused by pathogenic Leptospira spp. It is an important infectious disease that affects humans and animals. The disease causes economic losses as it affects livestock, with decreased milk production and death. Our group is investigating the genome sequences of L. interrogans targeting surface-exposed proteins because, due to their location, these proteins are capable to interact with several host components that could allow establishment of the infection. These interactions may involve adhesion of the bacteria to extracellular matrix (ECM) components and, hence, help bacterial colonization. The bacteria could also react with the host fibrinolytic system and/or with the coagulation cascade components, such as, plasminogen (PLG) and fibrinogen (Fg), respectively. The binding with the first system generates plasmin (PLA), increasing the proteolytic power of the bacteria, while the second interferes with clotting in a thrombin-catalyzed reaction, which may promote hemorrhage foci and increase bacterial dissemination. Interaction with the complement system negative regulators may help bacteria to evade the host immune system, facilitating the invasion. This work compiles the main described leptospiral proteins that could act as adhesins, as PLG and fibrinogen receptors and as complement regulator binding proteins. We present models in which we suggest possible mechanisms of how leptospires might colonize and invade host tissues, causing the disease. Understanding leptospiral pathogenesis will help to identify antigen candidates that would contribute to the development of more effective vaccines and diagnostic tests. PMID:26727033

  14. Matrix ALPS: Accelerated Low Rank and Sparse Matrix Reconstruction

    CERN Document Server

    Kyrillidis, Anastasios

    2012-01-01

    We propose Matrix ALPS for recovering a sparse plus low-rank decomposition of a matrix given its corrupted and incomplete linear measurements. Our approach is a first-order projected gradient method over non-convex sets, and it exploits a well-known memory-based acceleration technique. We theoretically characterize the convergence properties of Matrix ALPS using the stable embedding properties of the linear measurement operator. We then numerically illustrate that our algorithm outperforms the existing convex as well as non-convex state-of-the-art algorithms in computational efficiency without sacrificing stability.

  15. Porous Silicon—A Versatile Host Material

    Directory of Open Access Journals (Sweden)

    Klemens Rumpf

    2010-02-01

    Full Text Available This work reviews the use of porous silicon (PS as a nanomaterial which is extensively investigated and utilized for various applications, e.g., in the fields of optics, sensor technology and biomedicine. Furthermore the combination of PS with one or more materials which are also nanostructured due to their deposition within the porous matrix is discussed. Such nanocompounds offer a broad avenue of new and interesting properties depending on the kind of involved materials as well as on their morphology. The filling of the pores performed by electroless or electrochemical deposition is described, whereas different morphologies, reaching from micro- to macro pores are utilized as host material which can be self-organized or fabricated by prestructuring. For metal-deposition within the porous structures, both ferromagnetic and non-magnetic metals are used. Emphasis will be put on self-arranged mesoporous silicon, offering a quasi-regular pore arrangement, employed as template for filling with ferromagnetic metals. By varying the deposition parameters the precipitation of the metal structures within the pores can be tuned in geometry and spatial distribution leading to samples with desired magnetic properties. The correlation between morphology and magnetic behaviour of such semiconducting/magnetic systems will be determined. Porous silicon and its combination with a variety of filling materials leads to nanocomposites with specific physical properties caused by the nanometric size and give rise to a multiplicity of potential applications in spintronics, magnetic and magneto-optic devices, nutritional food additives as well as drug delivery.

  16. Host Event Based Network Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan Chugg

    2013-01-01

    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  17. Undiscovered Bat Hosts of Filoviruses

    Science.gov (United States)

    Schmidt, John Paul; Alexander, Laura W.; Bowden, Sarah E.; Hayman, David T. S.; Drake, John M.

    2016-01-01

    Ebola and other filoviruses pose significant public health and conservation threats by causing high mortality in primates, including humans. Preventing future outbreaks of ebolavirus depends on identifying wildlife reservoirs, but extraordinarily high biodiversity of potential hosts in temporally dynamic environments of equatorial Africa contributes to sporadic, unpredictable outbreaks that have hampered efforts to identify wild reservoirs for nearly 40 years. Using a machine learning algorithm, generalized boosted regression, we characterize potential filovirus-positive bat species with estimated 87% accuracy. Our model produces two specific outputs with immediate utility for guiding filovirus surveillance in the wild. First, we report a profile of intrinsic traits that discriminates hosts from non-hosts, providing a biological caricature of a filovirus-positive bat species. This profile emphasizes traits describing adult and neonate body sizes and rates of reproductive fitness, as well as species’ geographic range overlap with regions of high mammalian diversity. Second, we identify several bat species ranked most likely to be filovirus-positive on the basis of intrinsic trait similarity with known filovirus-positive bats. New bat species predicted to be positive for filoviruses are widely distributed outside of equatorial Africa, with a majority of species overlapping in Southeast Asia. Taken together, these results spotlight several potential host species and geographical regions as high-probability targets for future filovirus surveillance. PMID:27414412

  18. AVTC Hosts TechnoCamp

    Science.gov (United States)

    Miner, Brenda

    2006-01-01

    The Area Vo-Tech Center (AVTC) in Russellville, Arkansas, recently hosted its first TechnoCamp to encourage enrollment based on the aptitude and interest level of the students enrolling in the various programs. The center currently offers student enrollment in auto technology, computer engineering, cosmetology, construction technology, drafting…

  19. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  20. The matrix of inspiration

    Science.gov (United States)

    Oehlmann, Dietmar; Ohlmann, Odile M.; Danzebrink, Hans U.

    2005-04-01

    perform this exchange, as a matrix, understood as source, of new ideas.

  1. Containment Code Validation Matrix

    International Nuclear Information System (INIS)

    The Committee on the Safety of Nuclear Installations (CSNI) formed the CCVM (Containment Code Validation Matrix) task group in 2002. The objective of this group was to define a basic set of available experiments for code validation, covering the range of containment (ex-vessel) phenomena expected in the course of light and heavy water reactor design basis accidents and beyond design basis accidents/severe accidents. It was to consider phenomena relevant to pressurised heavy water reactor (PHWR), pressurised water reactor (PWR) and boiling water reactor (BWR) designs of Western origin as well as of Eastern European VVER types. This work would complement the two existing CSNI validation matrices for thermal hydraulic code validation (NEA/CSNI/R(1993)14) and In-vessel core degradation (NEA/CSNI/R(2001)21). The report initially provides a brief overview of the main features of a PWR, BWR, CANDU and VVER reactors. It also provides an overview of the ex-vessel corium retention (core catcher). It then provides a general overview of the accident progression for light water and heavy water reactors. The main focus is to capture most of the phenomena and safety systems employed in these reactor types and to highlight the differences. This CCVM contains a description of 127 phenomena, broken down into 6 categories: - Containment Thermal-hydraulics Phenomena; - Hydrogen Behaviour (Combustion, Mitigation and Generation) Phenomena; - Aerosol and Fission Product Behaviour Phenomena; - Iodine Chemistry Phenomena; - Core Melt Distribution and Behaviour in Containment Phenomena; - Systems Phenomena. A synopsis is provided for each phenomenon, including a description, references for further information, significance for DBA and SA/BDBA and a list of experiments that may be used for code validation. The report identified 213 experiments, broken down into the same six categories (as done for the phenomena). An experiment synopsis is provided for each test. Along with a test description

  2. Evaluation of lymphangiogenesis in acellular dermal matrix

    Directory of Open Access Journals (Sweden)

    Mario Cherubino

    2014-01-01

    Full Text Available Introduction: Much attention has been directed towards understanding the phenomena of angiogenesis and lymphangiogenesis in wound healing. Thanks to the manifold dermal substitute available nowadays, wound treatment has improved greatly. Many studies have been published about angiogenesis and cell invasion in INTEGRA® . On the other hand, the development of the lymphatic network in acellular dermal matrix (ADM is a more obscure matter. In this article, we aim to characterize the different phases of host cell invasion in ADM. Special attention was given to lymphangiogenic aspects. Materials and Methods: Among 57 rats selected to analyse the role of ADM in lymphangiogenesis, we created four groups. We performed an excision procedure on both thighs of these rats: On the left one we did not perform any action except repairing the borders of the wound; while on the right one we used INTEGRA® implant. The excision biopsy was performed at four different times: First group after 7 days, second after 14 days, third after 21 days and fourth after 28 days. For our microscopic evaluation, we used the classical staining technique of haematoxylin and eosin and a semi-quantitative method in order to evaluate cellularity counts. To assess angiogenesis and lymphangiogenesis development we employed PROX-1 Ab and CD31/PECAM for immunohistochemical analysis. Results: We found remarkable wound contraction in defects that healed by secondary intention while minor wound contraction was observed in defects treated with ADM. At day 7, optical microscopy revealed a more plentiful cellularity in the granulation tissue compared with the dermal regeneration matrix. The immunohistochemical process highlighted vascular and lymphatic cells in both groups. After 14 days a high grade of fibrosis was noticeable in the non-treated group. At day 21, both lymphatic and vascular endothelial cells were better developed in the group with a dermal matrix application. At day 28

  3. Host range of symptomatology of Pepino mosaic virus strains occurring in Europe

    DEFF Research Database (Denmark)

    Blystad, Dag-Ragnar; van der Vlugt, René; Alfaro-Fernández, Ana; del Carmen Córdoba, María; Bese, Gábor; Hristova, Dimitrinka; Pospieszny, Henryk; Mehle, Natasa; Ravnikar, Maja; Tomassoli, Laura; Varveri, Christina; Nielsen, Steen Lykke

    2015-01-01

    Solanaceae and selected test plants. The inoculation experiments were done in 10 countries from south to north in Europe. The importance of alternative hosts among the solanaceous crops and the usefulness of test plants in the biological characterization of PepMV isolates are discussed. Our data for the......Pepino mosaic virus (PepMV) has caused great concern in the greenhouse tomato industry after it was found causing a new disease in tomato in 1999. The objective of this paper is to investigate alternative hosts and compare important biological characteristics of the three PepMV strains occurring in...... Europe when tested under different environmental conditions. To this end we compared the infectivity and symptom Development of three, well characterized isolates belonging to three different PepMV strains, EU-tom, Ch2 and US1, by inoculating them on tomato, possible alternative host plants in the family...

  4. Manufacturing Titanium Metal Matrix Composites by Consolidating Matrix Coated Fibres

    Institute of Scientific and Technical Information of China (English)

    Hua-Xin PENG

    2005-01-01

    Titanium metal matrix composites (TiMMCs) reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre (MCF) method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing (VHP). In contrast to most of existing studies, the fibre arrangement has been carefully controlled either in square or hexagonal arraysthroughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.

  5. Prospects of host-associated microorganisms in fish and penaeids as probiotics with immunomodulatory functions

    DEFF Research Database (Denmark)

    Lazado, Carlo Cabacang; Caipang, Christopher Marlowe A.; Estante, Erish G.

    2015-01-01

    . Host-derived probiotics have gained popularity in recent years as they offer an alternative source of beneficial microbes to the industry that is customarily dependent on the use of terrestrial microorganisms. At present, there is an overwhelming number of candidate probiotics in aquaculture but their...... capabilities of host-derived candidate probiotics are given to establish the current knowledge and provide avenues for future research and development in this thematic area of probiotics research in aquaculture...

  6. Seal design alternatives study

    International Nuclear Information System (INIS)

    This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information

  7. Seal design alternatives study

    Energy Technology Data Exchange (ETDEWEB)

    Van Sambeek, L.L. [RE/SPEC Inc., Rapid City, SD (US); Luo, D.D.; Lin, M.S.; Ostrowski, W.; Oyenuga, D. [Parsons Brinckerhoff Quade & Douglas, Inc., San Francisco, CA (US)

    1993-06-01

    This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information.

  8. An alternative currency

    OpenAIRE

    Frendo, Mario; Duca, Edward

    2013-01-01

    Malta- a tiny island, a minute social reality, a precursory canovaccio of European unification- has a unique asset it ought to be prouder of: culture. http://www.um.edu.mt/think/an-alternative-currency/

  9. Alternatives to Nursing Homes

    Science.gov (United States)

    ... this website may not be available. Alternatives to nursing homes Before you make any decisions about long ... live and what help you may need. A nursing home may not be your only choice. Discharge ...

  10. Vaginal dryness alternative treatments

    Science.gov (United States)

    ... a day. Soybeans contain plant-based substances called isoflavones. These substances have an effect on the body ... soy for vasomotor symptoms: the Herbal Alternatives for Menopause (HALT) Study. Menopause . 2008;15(1):51-58. ...

  11. Alternative fuel information sources

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This short document contains a list of more than 200 US sources of information (Name, address, phone number, and sometimes contact) related to the use of alternative fuels in automobiles and trucks. Electric-powered cars are also included.

  12. Measuring methods of matrix diffusion

    International Nuclear Information System (INIS)

    In Finland the spent nuclear fuel is planned to be disposed of at large depths in crystalline bedrock. The radionuclides which are dissolved in the groundwater may be able to diffuse into the micropores of the porous rock matrix and thus be withdrawn from the flowing water in the fractures. This phenomenon is called matrix diffusion. A review over matrix diffusion is presented in the study. The main interest is directed to the diffusion of non-sorbing species. The review covers diffusion experiments and measurements of porosity, pore size, specific surface area and water permeability

  13. Matrix models for 2* theories

    International Nuclear Information System (INIS)

    We show how to represent a class of expressions involving discrete sums over partitions as matrix models. We apply this technique to the partition functions of 2* theories, i.e. Seiberg-Witten theories with the massive hypermultiplet in the adjoint representation. We consider theories in four, five, and six dimensions, and obtain new matrix models, respectively, of rational, trigonometric, and elliptic type. The matrix models for five- and six-dimensional U(1) theories are derived from the topological vertex construction related to curves of genus one and two.

  14. Canonical density matrix perturbation theory.

    Science.gov (United States)

    Niklasson, Anders M N; Cawkwell, M J; Rubensson, Emanuel H; Rudberg, Elias

    2015-12-01

    Density matrix perturbation theory [Niklasson and Challacombe, Phys. Rev. Lett. 92, 193001 (2004)] is generalized to canonical (NVT) free-energy ensembles in tight-binding, Hartree-Fock, or Kohn-Sham density-functional theory. The canonical density matrix perturbation theory can be used to calculate temperature-dependent response properties from the coupled perturbed self-consistent field equations as in density-functional perturbation theory. The method is well suited to take advantage of sparse matrix algebra to achieve linear scaling complexity in the computational cost as a function of system size for sufficiently large nonmetallic materials and metals at high temperatures. PMID:26764847

  15. The alternative library

    OpenAIRE

    Collinson, Timothy; A. Williams

    2004-01-01

    Much time and effort has been devoted to designing and developing library Web sites that are easy to navigate by both new students and experienced researchers. In a review of the Southampton Institute Library it was decided that in addition to updating the existing homepage an alternative would be offered. Drawing on theory relating to user interface design, learning styles and creative thinking, an Alternative Library navigation system was added to the more traditional library homepage. The ...

  16. Alternative fuel cycles

    International Nuclear Information System (INIS)

    Uranium resource utilization and economic considerations provide incentives to study alternative fuel cycles as future options to the PHWR natural uranium cycle. Preliminary studies to define the most favourable alternatives and their possible introduction dates are discussed. The important and uncertain components which influence option selection are reviewed, including nuclear capacity growth, uranium availability and demand, economic potential, and required technological developments. Finally, a summary of Ontario Hydro's program to further assess cycle selection and define development needs is given. (auth)

  17. Ultimacy and alternative possibilities

    OpenAIRE

    Fischer, John Martin

    2009-01-01

    I explore a key feature of Robert Kane’s libertarianism (about which I have been puzzled for some time). Kane claims that we should separate issues of alternative possibilities from issues of ultimacy, but he further argues that they are connected in a certain way. I call into question this connection, and I continue to argue for a strict separation of considerations pertaining to alternative possibilities and “actual-sequence” considerations.

  18. Des divisions aux alternances

    Directory of Open Access Journals (Sweden)

    Eric Clemens

    2012-12-01

    Full Text Available - From the divisions to the alternations - Society, action and common good give sense to democracy. Society is in fact a set of unmitigated divisions (horizontal and vertical, material and symbolic. Democratic action, since the discourse’s conflicts, doesn’t change the human beings, but things between they, in the alternation of power’s institutions for our only good in common: the body. With this aim, the Basic Income Earth Network is necessary.

  19. Alternatives for Bulgarian forests

    NARCIS (Netherlands)

    Päivinen, R.; Nabuurs, G.J.

    2001-01-01

    The European Forest Information Scenario Model (EFISCEN) is an area-based forest matrix model, which is especially suitable for projections of forest resources of large areas under assumptions of total national felling. EFISCEN uses time steps of five years and national forest inventory data. The in

  20. Location of Host and Host Habitat by Fruit Fly Parasitoids

    Directory of Open Access Journals (Sweden)

    Pascal Rousse

    2012-11-01

    Full Text Available Augmentative releases of parasitoids may be a useful tool for the area-wide management of tephritid pests. The latter are parasitized by many wasp species, though only a few of them are relevant for augmentative biocontrol purposes. To date, nearly all the actual or potential biocontrol agents for such programs are egg or larval Opiinae parasitoids (Hymenoptera: Braconidae. Here, we review the literature published on their habitat and host location behavior, as well as the factors that modulate this behavior, which is assumed to be sequential; parasitoids forage first for the host habitat and then for the host itself. Parasitoids rely on chemical, visual, and mechanical stimuli, often strongly related to their ecology. Behavioral modulation factors include biotic and abiotic factors including learning, climatic conditions and physiological state of the insect. Finally, conclusions and perspectives for future research are briefly highlighted. A detailed knowledge of this behavior may be very useful for selecting the release sites for both inundative/augmentative releases of mass-reared parasitoids and inoculative releases for classical biocontrol.

  1. Pulsewidth Modulation of Neutral-Point-Clamped Indirect Matrix Converter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Poh Chiang, Loh; Gao, Feng;

    2008-01-01

    An indirect matrix converter is an alternative "all-semiconductor" energy processor proposed recently for converting an ac source with fixed magnitude and frequency to a variable voltage and frequency supply that can meet the requirements of a particular industry application. In principle, an...... indirect matrix converter is constructed by connecting a front-end bidirectional rectification stage to a conventional two-level inversion stage with no bulky capacitive or inductive energy storage connected to their intermediate dc link. Through the proper modulation and compensation of the resulting...... converter, sinusoidal input current and output voltage can be achieved with minimized rectification switching loss, rendering the indirect matrix converter as a competitive choice for interfacing the utility grid to, e.g., defense facilities that require a different frequency supply. As an improvement, an...

  2. Matrix isolation studies with Fourier transform ir

    International Nuclear Information System (INIS)

    The combination of Fourier transform infrared (FT-IR) spectroscopy with the matrix-isolation techniques has advantages compared with the use of more conventional grating spectroscopy. Furthermore, the recent commercial availability of Fourier transform spectrometers has made FT-IR a practical alternative. Some advantages of the FT-IR spectrometer over the grating spectrometer are the result of the computerized data system that is a necessary part of the FT-IR spectrometer; other advantages are a consequence of the difference in optical arrangements and these represent the inherent advantages of the FT-IR method. In most applications with the matrix-isolation technique, the use of FT-IR spectroscopy results in either an improved signal-to-noise ratio or a shorter time for data collection compared with grating infrared spectroscopy. Fourier transform infrared spectroscopy has been used in the laboratory to study several molecular species in low-temperature matrices. Some species have been produced by high-temperature vaporization from Knudsen cells and others by sputtering. By sputtering, Ar and Kr matrices have been prepared which contain U atoms, UO, UO2, UO3, PuO, PuO2, UN, or UN2, depending upon the composition of the gas used to sputter as well as the identity of the metallic cathode. Infrared spectra of matrices containing these compounds are presented and discussed

  3. Multiple graph regularized nonnegative matrix factorization

    KAUST Repository

    Wang, Jingyan

    2013-10-01

    Non-negative matrix factorization (NMF) has been widely used as a data representation method based on components. To overcome the disadvantage of NMF in failing to consider the manifold structure of a data set, graph regularized NMF (GrNMF) has been proposed by Cai et al. by constructing an affinity graph and searching for a matrix factorization that respects graph structure. Selecting a graph model and its corresponding parameters is critical for this strategy. This process is usually carried out by cross-validation or discrete grid search, which are time consuming and prone to overfitting. In this paper, we propose a GrNMF, called MultiGrNMF, in which the intrinsic manifold is approximated by a linear combination of several graphs with different models and parameters inspired by ensemble manifold regularization. Factorization metrics and linear combination coefficients of graphs are determined simultaneously within a unified object function. They are alternately optimized in an iterative algorithm, thus resulting in a novel data representation algorithm. Extensive experiments on a protein subcellular localization task and an Alzheimer\\'s disease diagnosis task demonstrate the effectiveness of the proposed algorithm. © 2013 Elsevier Ltd. All rights reserved.

  4. Phase space bases for response matrix methods

    International Nuclear Information System (INIS)

    New basis functions in space, angle, and energy are developed for use in the eigenvalue response matrix method (ERMM). ERMM solves reactor eigenvalue problems by spatially decomposing a model and linking the resulting independent nodes through approximate boundary conditions. The conditions are defined via a set of nodal transport calculations for which the forcing function is a tensor product of basis functions in all phase space variables on one nodal surface (with vacuum elsewhere). Traditional implementations of ERMM have used the standard bases of mathematical physics, including Legendre polynomials and their discrete analogs. Alternatively, new bases that incorporate some physics a priori are shown to yield satisfactory results with far lower expansion orders than is possible with more traditional bases. In particular, a very simple spatial basis incorporating pin-dependent spatial variation reduces partial current errors by nearly an order of magnitude over a standard basis. In angle, conservative bases with appropriate angular quadratures outperform simpler bases. In energy, incorporating representative spectral information from infinite medium calculations results in a basis that can achieve sub-1% pin fission rate errors with as low as a 5th order expansion in energy for a 44-group problem. The results indicate that highly-accurate, low-order response matrix solutions should be feasible for reactor physics analysis. (author)

  5. PHOTOVOLTAIC ENERGY AS SUSTAINABLE ENERGETIC MATRIX IN COMPANIES

    OpenAIRE

    Barp, Carlos Alberto; Sehnem, Simone; Bencke, Fernando Fantoni

    2014-01-01

    The aim of this paper is investigate the evolution of the energetic photovoltaic matrix in the company NORD Eletric SA. This is justified by the importance of the sustainability and creation of clean energy making use of the emerging and innovative alternative in the regional area supporting the economic and environmental. The study used a qualitative and quantitative approach. The responsible for the company was interviewed and secondary data were researched. The techniques of analyze used w...

  6. Ceramic fiber reinforced glass-ceramic matrix composite

    Science.gov (United States)

    Bansal, Narottam P. (Inventor)

    1993-01-01

    A slurry of BSAS glass powders is cast into tapes which are cut to predetermined sizes. Mats of continuous chemical vapor deposition (CVD)-SiC fibers are alternately stacked with these matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite which is heated to burn out organic constituents. The remaining interim material is then hot-pressed to form a BSAS glass-ceramic fiber-reinforced composite.

  7. Conventional Quantum Mechanics Without Wave Function and Density Matrix

    OpenAIRE

    Man'ko, Vladimir I.

    1999-01-01

    The tomographic invertable map of the Wigner function onto the positive probability distribution function is studied. Alternatives to the Schr\\"odinger evolution equation and to the energy level equation written for the positive probability distribution are discussed. Instead of the transition probability amplitude (Feynman path integral) a transition probability is introduced. A new formulation of the conventional quantum mechanics (without wave function and density matrix) based on the ``pr...

  8. Matrix-State Particle Filter for Wishart Stochastic Volatility Processes

    OpenAIRE

    Roberto Casarin; Domenico Sartore

    2007-01-01

    This work deals with multivariate stochastic volatility models, which account for a time-varying variance-covariance structure of the observable variables. We focus on a special class of models recently proposed in the literature and assume that the covariance matrix is a latent variable which follows an autoregressive Wishart process. We review two alternative stochastic representations of the Wishart process and propose Markov-Switching Wishart processes to capture different regimes in the ...

  9. Benchmark calculations for reduced density-matrix functional theory

    OpenAIRE

    Lathiotakis, N.N.; Marques, Miguel A. L.

    2008-01-01

    Reduced density-matrix functional theory (RDMFT) is a promising alternative approach to the problem of electron correlation. Like standard density functional theory, it contains an unknown exchange-correlation functional, for which several approximations have been proposed in the last years. In this article, we benchmark some of these functionals in an extended set of molecules with respect to total and atomization energies. Our results show that the most recent RDMFT functionals give very sa...

  10. Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms.

    Science.gov (United States)

    Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R

    2016-07-01

    Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms. PMID:27394094

  11. Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms

    Science.gov (United States)

    Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R.

    2016-07-01

    Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.

  12. Fibrinogen Is at the Interface of Host Defense and Pathogen Virulence in Staphylococcus aureus Infection.

    Science.gov (United States)

    Ko, Ya-Ping; Flick, Matthew J

    2016-06-01

    Fibrinogen not only plays a pivotal role in hemostasis but also serves key roles in antimicrobial host defense. As a rapidly assembled provisional matrix protein, fibrin(ogen) can function as an early line of host protection by limiting bacterial growth, suppressing dissemination of microbes to distant sites, and mediating host bacterial killing. Fibrinogen-mediated host antimicrobial activity occurs predominantly through two general mechanisms, namely, fibrin matrices functioning as a protective barrier and fibrin(ogen) directly or indirectly driving host protective immune function. The potential of fibrin to limit bacterial infection and disease has been countered by numerous bacterial species evolving and maintaining virulence factors that engage hemostatic system components within vertebrate hosts. Bacterial factors have been isolated that simply bind fibrinogen or fibrin, promote fibrin polymer formation, or promote fibrin dissolution. Staphylococcus aureus is an opportunistic gram-positive bacterium, the causative agent of a wide range of human infectious diseases, and a prime example of a pathogen exquisitely sensitive to host fibrinogen. Indeed, current data suggest fibrinogen serves as a context-dependent determinant of host defense or pathogen virulence in Staphylococcus infection whose ultimate contribution is dictated by the expression of S. aureus virulence factors, the path of infection, and the tissue microenvironment. PMID:27056151

  13. The epidemiological feedbacks critical to the evolution of host immunity.

    Science.gov (United States)

    Donnelly, R; White, A; Boots, M

    2015-11-01

    We examine in detail how epidemiological feedbacks combine with costs and benefits to determine the evolution of resistance by systematically analysing continuously stable strategies (CSS) for different host-parasite frameworks. The mode of resistance (innate versus acquired), the nature of the host (i.e. life-history and immunological memory) and the nature of the disease (effects on fertility or mortality) all impact on the feedbacks that are critical to the evolution of resistance. By identifying relationships between CSS investment and the underlying epidemiological feedback for each mode of resistance in each framework, we distil complex feedbacks into simple combinations of selection pressures. When the parasite does not affect fertility, CSS investment reflects only the benefit of resistance and we explain why this is markedly different for innate and acquired resistance. If infection has no effect on host fertility, CSS investment in acquired immunity increases with the square of disease prevalence. While in contrast for evolving innate resistance, CSS investment is greatest at intermediate prevalence. When disease impacts fertility, only a fraction of the host population reproduce, and this introduces new ecological feedbacks to both the cost of resistance and the damage from infection. The multiple feedbacks in this case lead to the alternative result that the higher the abundance of infecteds, the higher the investment in innate resistance. A key insight is that maximal investment occurs at intermediate lifespans in a range of different host-parasite interactions, but for disparate reasons which can only be understood by a detailed analysis of the feedbacks. We discuss the extension of our approach to structured host populations and parasite community dynamics. PMID:26285917

  14. Bilateral matrix-exponential distributions

    DEFF Research Database (Denmark)

    Bladt, Mogens; Esparza, Luz Judith R; Nielsen, Bo Friis

    2012-01-01

    In this article we define the classes of bilateral and multivariate bilateral matrix-exponential distributions. These distributions have support on the entire real space and have rational moment-generating functions. These distributions extend the class of bilateral phasetype distributions of [1......] and the class of multivariate matrix-exponential distributions of [9]. We prove a characterization theorem stating that a random variable has a bilateral multivariate distribution if and only if all linear combinations of the coordinates have a univariate bilateral matrix-exponential distribution. As...... an application we demonstrate that certain multivariate disions, which are governed by the underlying Markov jump process generating a phasetype distribution, have a bilateral matrix-exponential distribution at the time of absorption, see also [4]....

  15. GoM Diet Matrix

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set was taken from CRD 08-18 at the NEFSC. Specifically, the Gulf of Maine diet matrix was developed for the EMAX exercise described in that center...

  16. Matrix Quantum Mechanics from Qubits

    CERN Document Server

    Hartnoll, Sean A; Mazenc, Edward A

    2016-01-01

    We introduce a transverse field Ising model with order N^2 spins interacting via a nonlocal quartic interaction. The model has an O(N,Z), hyperoctahedral, symmetry. We show that the large N partition function admits a saddle point in which the symmetry is enhanced to O(N). We further demonstrate that this `matrix saddle' correctly computes large N observables at weak and strong coupling. The matrix saddle undergoes a continuous quantum phase transition at intermediate couplings. At the transition the matrix eigenvalue distribution becomes disconnected. The critical excitations are described by large N matrix quantum mechanics. At the critical point, the low energy excitations are waves propagating in an emergent 1+1 dimensional spacetime.

  17. The reciprocal super Catalan matrix

    OpenAIRE

    Prodinger Helmut

    2015-01-01

    The reciprocal super Catalan matrix has entries . Explicit formulæ for its LU-decomposition, the LU-decomposition of its inverse, and some related matrices are obtained. For all results, q-analogues are also presented.

  18. Preferential host switching and its relation with Hantavirus diversification in South America.

    Science.gov (United States)

    Rivera, Paula C; González-Ittig, Raul E; Gardenal, Cristina N

    2015-09-01

    In recent years, the notion of co-speciation between Hantavirus species and their hosts was discarded in favour of a more likely explanation: preferential host switching. However, the relative importance of this last process in shaping the evolutionary history of hantaviruses remains uncertain, given the present limited knowledge not only of virus-host relationships but also of the pathogen and reservoir phylogenies. In South America, more than 25 hantavirus genotypes were detected; several of them act as aetiological agents of hantavirus pulmonary syndrome (HPS). An understanding of the diversity of hantaviruses and of the processes underlying host switching is critical since human cases of HPS are almost exclusively the result of human-host interactions. In this study, we tested if preferential host switching is the main process driving hantavirus diversification in South America, by performing a co-phylogenetic analysis of the viruses and their primary hosts. We also suggest a new level of amino acid divergence to define virus species in the group. Our results indicate that preferential host switching would not be the main process driving virus diversification. The historical geographical proximity among rodent hosts emerges as an alternative hypothesis to be tested. PMID:26048884

  19. An Aggregation Matrix MATLAB Function

    OpenAIRE

    Caleb Stair

    2013-01-01

    This Technical Document describes the foundations for an aggregation matrix function implemented in MATLAB, including the format and structure of the required aggregation vector used as an argument to the function. The function is passed with the N-dimensional aggregation vector as an argument. The aggregation vector contains N values ranging from 1 to M, each of which is the aggregate index corresponding to the N pre-aggregation indices. The function returns an aggregation matrix with M rows...

  20. Matrix analysis of electrical machinery

    CERN Document Server

    Hancock, N N

    2013-01-01

    Matrix Analysis of Electrical Machinery, Second Edition is a 14-chapter edition that covers the systematic analysis of electrical machinery performance. This edition discusses the principles of various mathematical operations and their application to electrical machinery performance calculations. The introductory chapters deal with the matrix representation of algebraic equations and their application to static electrical networks. The following chapters describe the fundamentals of different transformers and rotating machines and present torque analysis in terms of the currents based on the p

  1. The matrix rate of return

    Science.gov (United States)

    Zambrzycka, Anna; Piotrowski, Edward W.

    2007-08-01

    In this paper we give definitions of matrix rates of return which do not depend on the choice of basis describing baskets. We give their economic interpretation. The matrix rate of return describes baskets of arbitrary type and extends portfolio analysis to the complex variable domain. This allows us for simultaneous analysis of evolution of baskets parameterized by complex variables in both continuous and discrete time models.

  2. The matrix rate of return

    CERN Document Server

    Zambrzycka, A; Zambrzycka, Anna; Piotrowski, Edward W.

    2006-01-01

    In this paper we give definitions of matrix rates of return which do not depend on the choice of basis describing baskets. We give their economic interpretation. The matrix rate of return describes baskets of arbitrary type and extends portfolio analysis to the complex variable domain. This allows us for simultaneous analysis of evolution of baskets parameterized by complex variables in both continuous and discrete time models.

  3. Hyaluronan-Dependent Pericellular Matrix

    OpenAIRE

    Evanko, Stephen P.; Tammi, Markku I; Tammi, Raija H.; Wight, Thomas N.

    2007-01-01

    Hyaluronan is a multifunctional glycosaminoglycan that forms the structural basis of the pericellular matrix. Hyaluronan is extruded directly through the plasma membrane by one of three hyaluronan synthases and anchored to the cell surface by the synthase or cell surface receptors such as CD44 or RHAMM. Aggregating proteoglycans and other hyaluronan-binding proteins, contribute to the material and biological properties of the matrix and regulate cell and tissue function. The pericellular matr...

  4. Flows for rectangular matrix models

    OpenAIRE

    Lafrance, Rene; Myers, Robert C.

    1993-01-01

    Several new results on the multicritical behavior of rectangular matrix models are presented. We calculate the free energy in the saddle point approximation, and show that at the triple-scaling point, the result is the same as that derived from the recursion formulae. In the triple-scaling limit, we obtain the string equation and a flow equation for arbitrary multicritical points. Parametric solutions are also examined for the limit of almost-square matrix models. This limit is shown to provi...

  5. Staggered chiral random matrix theory

    International Nuclear Information System (INIS)

    We present a random matrix theory for the staggered lattice QCD Dirac operator. The staggered random matrix theory is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.

  6. Thermoplastic Matrix Composites from Towpregs

    OpenAIRE

    Silva, João; Nunes, João; Bernardo, C. A.; Marques, António

    2011-01-01

    In recent years, continuous fibre reinforced thermoplastic matrix composites have been successfully employed in the aircraft, military and aerospace industries due to the excellent properties (Brandt et al. 1993 & Nunes et al 2005a). In these and many other commercial engineering applications, they can replace other materials, such as thermosetting matrix composites. However, the high cost of the impregnation of continuous fibre thermoplastic composites, arising from the meltin...

  7. AGN and their host galaxies

    Science.gov (United States)

    Steinborn, L. K.; Dolag, K.; Hirschmann, M.; Remus, R.-S.; Teklu, A. F.

    2016-06-01

    Large scale cosmological hydrodynamic simulations are an important tool to study the co-evolution between black holes (BHs) and their host galaxies. However, in order to model the accretion onto BHs and AGN feedback we need sub-grid models which contain several free parameters. The choice of these parameters has a significant impact on the properties of the BHs and their host galaxies. Therefore, we improve the accretion model and the AGN feedback model based on both theory and observations to eliminate most free parameters. In that way, the slope of the observed relation between BH mass and stellar mass is reproduced self-consistently. We performed a few extremely large simulation runs as part of the Magneticum Pathfinder simulation set, combining a high resolution with very large cosmological volumes, enabling us to study for example dual AGN, the role of galaxy mergers and AGN clustering properties.

  8. Host modulation by therapeutic agents

    Directory of Open Access Journals (Sweden)

    Sugumari Elavarasu

    2012-01-01

    Full Text Available Periodontal disease susceptible group present advanced periodontal breakdown even though they achieve a high standard of oral hygiene. Various destructive enzymes and inflammatory mediators are involved in destruction. These are elevated in case of periodontal destruction. Host modulation aims at bringing these enzymes and mediators to normal level. Doxycycline, nonsteroidal anti-inflammatory drugs (NSAIDs, bisphosphonates, nitrous oxide (NO synthase inhibitors, recombinant human interleukin-11 (rhIL-11, omega-3 fatty acid, mouse anti-human interleukin-6 receptor antibody (MRA, mitogen-activated protein kinase (MAPK inhibitors, nuclear factor-kappa B (NF-kb inhibitors, osteoprotegerin, and tumor necrosis factor antagonist (TNF-α are some of the therapeutic agents that have host modulation properties.

  9. Exoplanets and their Host Stars

    Science.gov (United States)

    Schmitt, J.

    2016-06-01

    Among the most fundamental astrophysical discoveries are clearly the detections of many thousands of ``extrasolar'' planets orbiting their hosts. The majority of these new planetary systems have properties dramatically different from those in our solar system. The large distances to extrasolar planets imply that they can only be observed together with their hosts. Modern observations have shown that stars and planets are not merely accidental celestial neighbors bound by the force of gravity, rather they influence each other in a variety of ways. This also and specifically applies to the X-ray properties of exoplanet systems which I will review in my talk and give some ideas for future work in this area.

  10. Virus-specific host miRNAs: antiviral defenses or promoters of persistent infection?

    OpenAIRE

    Mahajan, Vinay S.; Drake, Adam; Chen, Jianzhu

    2008-01-01

    The discovery of host-microRNA (miRNA) targets in the genomes of many vertebrate viruses indicates that the corresponding miRNAs are a part of the host’s innate antiviral defense. However, given that viruses evolve much faster than host miRNAs, it is surprising that viral variants lacking these “antiviral” miRNA target sequences have not become established. We present an alternate view that miRNAs are among the host molecules that viruses co-opt to suppress their own replication to evade immu...

  11. Corrosion of ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Scanu, T. (ONERA-OM, 92 Chatillon (France) LASIR, CNRS, 94 Thiais (France)); Colomban, P. (ONERA-OM, 92 Chatillon (France) LASIR, CNRS, 94 Thiais (France))

    1993-11-01

    Air stable ceramic matrix composites are promising for thermostructural applications such as aircraft engine parts. Turbine parts are subject to both sulphuric acid and sodium molten salts corrosion due to sulphate traces in engine fuel and to the NaCl air content. The chemical stability is a very important criterion but this point has not received much attention to date. We report here a study of acidic and sodium corrosion of various aluminosilicate matrices : LAS matrices (Li[sub 2]OAl[sub 2]O[sub 3]2-6SiO[sub 2],nP[sub 2]O[sub 5]) in the amorphous, [beta] eucryptite and [beta] spodumene forms, BAS matrix (BaOAl[sub 2]O[sub 3]2SiO[sub 2]) in the form of monoclinic and hexagonal celsian, NASICON matrix (Na[sub 3]Zr[sub 2]Si[sub 2]PO[sub 12]) and mullite matrix. Microstructure damages and ion exchange have been analysed by X-ray diffraction, IR absorption, scanning electron microscopy and Raman microprobe. Drastic corrosion is observed for [beta] spodumene containing composites with the formation of strong hydrogen bond or with the cell expansion due to Li/Na[sup +] exchange. Medium acidic attack occurs for glassy LAS, [beta] eucryptite, BAS and NASICON matrix composites. On the other hand, [beta] eucryptite, NASICON and monoclinic celsian resist to alkaline melts. Mullite matrix composites are never corroded. (orig.).

  12. Corrosion of ceramic matrix composites

    International Nuclear Information System (INIS)

    Air stable ceramic matrix composites are promising for thermostructural applications such as aircraft engine parts. Turbine parts are subject to both sulphuric acid and sodium molten salts corrosion due to sulphate traces in engine fuel and to the NaCl air content. The chemical stability is a very important criterion but this point has not received much attention to date. We report here a study of acidic and sodium corrosion of various aluminosilicate matrices : LAS matrices (Li2OAl2O32-6SiO2,nP2O5) in the amorphous, β eucryptite and β spodumene forms, BAS matrix (BaOAl2O32SiO2) in the form of monoclinic and hexagonal celsian, NASICON matrix (Na3Zr2Si2PO12) and mullite matrix. Microstructure damages and ion exchange have been analysed by X-ray diffraction, IR absorption, scanning electron microscopy and Raman microprobe. Drastic corrosion is observed for β spodumene containing composites with the formation of strong hydrogen bond or with the cell expansion due to Li/Na+ exchange. Medium acidic attack occurs for glassy LAS, β eucryptite, BAS and NASICON matrix composites. On the other hand, β eucryptite, NASICON and monoclinic celsian resist to alkaline melts. Mullite matrix composites are never corroded. (orig.)

  13. M-theoretic matrix models

    CERN Document Server

    Grassi, Alba

    2014-01-01

    Some matrix models admit, on top of the usual 't Hooft expansion, an M-theory-like expansion, i.e. an expansion at large N but where the rest of the parameters are fixed, instead of scaling with N. These models, which we call M-theoretic matrix models, appear in the localization of Chern-Simons-matter theories, and also in two-dimensional statistical physics. Generically, their partition function receives non-perturbative corrections which are not captured by the 't Hooft expansion. In this paper, we discuss general aspects of these type of matrix integrals and we analyze in detail two different examples. The first one is the matrix model computing the partition function of N=4 supersymmetric Yang-Mills theory in three dimensions with one adjoint hypermultiplet and N_f fundamentals, which has a conjectured M-theory dual, and which we call the N_f matrix model. The second one, which we call the polymer matrix model, computes form factors of the 2d Ising model and is related to the physics of 2d polymers. In bo...

  14. Alternative fuels for vehicles; Alternative drivmidler

    Energy Technology Data Exchange (ETDEWEB)

    2012-02-15

    Up until 2020 and onwards the analysis indicates that especially electricity, biogas and natural gas as propellants is economically attractive compared to conventional gasoline and diesel while other fuels have the same or higher costs for petrol and diesel. Especially biogas and electricity will also offer significant reductions in CO{sub 2} emissions, but also hydrogen, methanol, DME and to a lesser extent the second generation bioethanol and most of the other alternative fuels reduce CO{sub 2} emissions. Use of the traditional food-based first generation biofuels involves, at best, only modest climate benefits if land use changes are counted, and at worst, significant negative climate effects. Natural gas as a propellant involves a moderate climate gain, but may play a role for building infrastructure and market for gaseous fuels in large fleets, thereby contributing to the phasing in of biogas for transport. The electric-based automotive fuels are the most effective due to a high efficiency of the engine and an increasing proportion of wind energy in the electricity supply. The methanol track also has a relatively high efficiency. Among the others, the track based on diesel engines (biodiesel) is more effective than the track based on gasoline/Otto engines (gas and ethanol) as a result of the diesel engine's better efficiency. For the heavy vehicles all the selected alternative fuels to varying degrees reduce emissions of CO{sub 2}, particularly DME based on wood. The only exception to this is - as for passenger cars - the propellant synthetic diesel based on coal. (LN).

  15. Cholesterol Biosensor Based on Entrapment of Monoenzyme and Multienzymes in Clay/Chitosan Hybrid Matrix

    Institute of Scientific and Technical Information of China (English)

    Dan Shan; YanNa Wang; HuaiGuo Xue; En Han

    2009-01-01

    @@ This work aimed at showing the interest of the composite material based on layered double hydroxides(LDHs) and chitosan (CHT) as suitable host matrix likely to immobilize enzyme onto electrode surface for amperometric biosensing application.This hybrid material combined the advantages of inorganic LDHs and organic biopolymer,CHT.

  16. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sacramento, R. L.; Alves, B. X.; Silva, B. A.; Wolff, W.; Cesar, C. L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Oliveira, A. N. [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); INMETRO, Av. Nossa Senhora das Graças, 50 25250-020 Duque de Caxias, RJ (Brazil); Li, M. S. [Instituto de Física de São Carlos, Universidade de São Paulo, Ave. Trabalhador São Carlense, 400, 13565-590 São Carlos, SP (Brazil)

    2015-07-15

    We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H{sub 2} are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

  17. Host specialization involving attraction, avoidance and performance, in two phytophagous moth species.

    Science.gov (United States)

    Orsucci, M; Audiot, P; Pommier, A; Raynaud, C; Ramora, B; Zanetto, A; Bourguet, D; Streiff, R

    2016-01-01

    Host specialization plays a key role in the extreme diversification of phytophagous insects. Whereas proximate mechanisms of specialization have been studied extensively, their consequences for species divergence remain unclear. Preference for, and performance on hosts are thought to be a major source of divergence in phytophagous insects. We assessed these major components of specialization in two moth species, the European corn borer (ECB) and the Adzuki bean borer (ABB), by testing their oviposition behaviour in different conditions (choice or no-choice set-ups) and their performances, by reciprocal transplant at the larval stage on the usual host and an alternative host plant. We demonstrated that both ABB and ECB have a strong preference for their host plants for oviposition, but that relative larval performances on the usual host and an alternative host differed according to the experiment and the trait considered (weight or survival). Finally, we show for the first time that the preference for maize in ECB conceals a strong avoidance of mugwort. The differences in performance, attraction and avoidance between ECB and ABB are discussed in the light of the underlying mechanisms and divergence process. PMID:26406269

  18. Evaluating Weeds as Hosts of Tomato yellow leaf curl virus.

    Science.gov (United States)

    Smith, Hugh A; Seijo, Teresa E; Vallad, Gary E; Peres, Natalia A; Druffel, Keri L

    2015-08-01

    Bemisia tabaci (Gennadius) biotype B transmits Tomato yellow leaf curl virus (TYLCV), which affects tomato production globally. Prompt destruction of virus reservoirs is a key component of virus management. Identification of weed hosts of TYLCV will be useful for reducing such reservoirs. The status of weeds as alternate hosts of TYLCV in Florida remains unclear. In greenhouse studies, B. tabaci adults from a colony reared on TYLCV-infected tomato were established in cages containing one of four weeds common to horticultural fields in central and south Florida. Cages containing tomato and cotton were also infested with viruliferous whiteflies as a positive control and negative control, respectively. Whitefly adults and plant tissue were tested periodically over 10 wk for the presence of TYLCV using PCR. After 10 wk, virus-susceptible tomato plants were placed in each cage to determine if whiteflies descended from the original adults were still infective. Results indicate that Bidens alba, Emilia fosbergii, and Raphanus raphanistrum are not hosts of TYLCV, and that Amaranthus retroflexus is a host. PMID:26314055

  19. Host-to-host variation of ecological interactions in polymicrobial infections

    OpenAIRE

    Mukherjee, Sayak; Weimer, Kristin E.; Seok, Sang-Cheol; Ray, Will C.; Jayaprakash, C.; Vieland, Veronica J; Swords, W. Edward; Das, Jayajit

    2014-01-01

    Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host-microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of di...

  20. Shifting preference between oviposition vs. host-feeding under changing host densities in two aphelinid parasitoids

    DEFF Research Database (Denmark)

    Yang, Nian-Wan; Ji, Lu-Lu; Lövei, Gabor L;

    2012-01-01

    Destructive host-feeding is common in hymenopteran parasitoids. Such feeding may be restricted to host stages not preferred for oviposition. However, whether this is a fixed strategy or can vary according to resource levels or parasitoid needs is less clear. We tested the trade-off between host....... The balance between reserving optimal hosts for oviposition or using them for host-feeding depended on parasitoid life history and the availability of host resources....

  1. Host compatibility rather than vector–host-encounter rate determines the host range of avian Plasmodium parasites

    OpenAIRE

    Medeiros, Matthew C. I.; Hamer, Gabriel L.; Robert E. Ricklefs

    2013-01-01

    Blood-feeding arthropod vectors are responsible for transmitting many parasites between vertebrate hosts. While arthropod vectors often feed on limited subsets of potential host species, little is known about the extent to which this influences the distribution of vector-borne parasites in some systems. Here, we test the hypothesis that different vector species structure parasite–host relationships by restricting access of certain parasites to a subset of available hosts. Specifically, we inv...

  2. SVD row or column symmetric matrix

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new architecture for row or column symmetric matrix called extended matrix is defined, and a precise correspondence of the singular values and singular vectors between the extended matrix and its original (namely, the mother matrix) is derived. As an illustration of potential, we show that, for a class of extended matrices, the singular value decomposition using the mother matrix rather than the extended matrix per se can save the CPU time and memory without loss of numerical precision.

  3. Catalysis for alternative energy generation

    CERN Document Server

    2012-01-01

    Summarizes recent problems in using catalysts in alternative energy generation and proposes novel solutions  Reconsiders the role of catalysis in alternative energy generation  Contributors include catalysis and alternative energy experts from across the globe

  4. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    Science.gov (United States)

    Stockton, Dara G; Martini, Xavier; Patt, Joseph M; Stelinski, Lukasz L

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  5. Molecular tracking of individual host use in the Shiny Cowbird - a generalist brood parasite.

    Science.gov (United States)

    de la Colina, Ma Alicia; Hauber, Mark E; Strausberger, Bill M; Reboreda, Juan Carlos; Mahler, Bettina

    2016-07-01

    Generalist parasites exploit multiple host species at the population level, but the individual parasite's strategy may be either itself a generalist or a specialist pattern of host species use. Here, we studied the relationship between host availability and host use in the individual parasitism patterns of the Shiny Cowbird Molothrus bonariensis, a generalist avian obligate brood parasite that parasitizes an extreme range of hosts. Using five microsatellite markers and an 1120-bp fragment of the mtDNA control region, we reconstructed full-sibling groups from 359 cowbird eggs and chicks found in nests of the two most frequent hosts in our study area, the Chalk-browed Mockingbird Mimus saturninus and the House Wren Troglodytes aedon. We were able to infer the laying behavior of 17 different females a posteriori and found that they were mostly faithful to a particular laying area and host species along the entire reproductive season and did not avoid using previously parasitized nests (multiple parasitism) even when other nests were available for parasitism. Moreover, we found females using the same host nest more than once (repeated parasitism), which had not been previously reported for this species. We also found few females parasitizing more than one host species. The use of an alternative host was not related to the main hosts' nest availability. Overall, female shiny cowbirds use a spatially structured and host species specific approach for parasitism, but they do so nonexclusively, resulting in both detectable levels of multiple parasitism and generalism at the level of individual parasites. PMID:27547305

  6. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    Directory of Open Access Journals (Sweden)

    Dara G Stockton

    Full Text Available Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a whether development on specific host plant species influenced host plant preference in mature D. citri; and b the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate

  7. Community impacts of anthropogenic disturbance: natural enemies exploit multiple routes in pursuit of invading herbivore hosts

    Directory of Open Access Journals (Sweden)

    Tavakoli Majid

    2010-10-01

    Full Text Available Abstract Background Biological invasions provide a window on the process of community assembly. In particular, tracking natural enemy recruitment to invading hosts can reveal the relative roles of co-evolution (including local adaptation and ecological sorting. We use molecular data to examine colonisation of northern Europe by the parasitoid Megastigmus stigmatizans following invasions of its herbivorous oak gallwasp hosts from the Balkans. Local host adaptation predicts that invading gallwasp populations will have been tracked primarily by sympatric Balkan populations of M. stigmatizans (Host Pursuit Hypothesis. Alternatively, ecological sorting allows parasitoid recruitment from geographically distinct populations with no recent experience of the invading hosts (Host Shift Hypothesis. Finally, we test for long-term persistence of parasitoids introduced via human trade of their hosts' galls (Introduction Hypothesis. Results Polymorphism diagnostic of different southern refugial regions was present in both mitochondrial and nuclear microsatellite markers, allowing us to identify the origins of northern European invaded range M. stigmatizans populations. As with their hosts, some invaded range populations showed genetic variation diagnostic of Balkan sources, supporting the Host Pursuit Hypothesis. In contrast, other invading populations had an Iberian origin, unlike their hosts in northern Europe, supporting the Host Shift Hypothesis. Finally, both British and Italian M. stigmatizans populations show signatures compatible with the Introduction Hypothesis from eastern Mediterranean sources. Conclusions These data reveal the continental scale of multi-trophic impacts of anthropogenic disturbance and highlight the fact that herbivores and their natural enemies may face very different constraints on range expansion. The ability of natural enemies to exploit ecologically-similar hosts with which they have had no historical association supports a

  8. Alternative Green Solvents Project

    Science.gov (United States)

    Maloney, Phillip R.

    2012-01-01

    Necessary for safe and proper functioning of equipment. Mainly halogenated solvents. Tetrachloride, Trichloroethylene (TCE), CFC-113. No longer used due to regulatory/safety concerns. Precision Cleaning at KSC: Small % of total parts. Used for liquid oxygen (LOX) systems. Dual solvent process. Vertrel MCA (decafluoropentane (DFP) and trons-dichloroethylene) HFE-7100. DFP has long term environmental concerns. Project Goals: a) Identify potential replacements. b) 22 wet chemical processes. c) 3 alternative processes. d) Develop test procedures. e) Contamination and cleaning. f) Analysis. g) Use results to recommend alternative processes. Conclusions: a) No alternative matched Vertrel in this study. b) No clear second place solvent. c) Hydrocarbons- easy; Fluorinated greases- difficult. d) Fluorinated component may be needed in replacement solvent. e) Process may need to make up for shortcoming of the solvent. f) Plasma and SCC02 warrant further testing.

  9. Alternatives for pseudofinite groups

    CERN Document Server

    Houcine, Abderezak Ould

    2012-01-01

    The famous Tits' alternative states that a linear group either contains a nonabelian free group or is soluble-by-(locally finite). We study in this paper similar alternatives in pseudofinite groups. We show for instance that an $\\aleph_{0}$-saturated pseudofinite group either contains a subsemigroup of rank $2$ or is nilpotent-by-(uniformly locally finite). We call a class of finite groups $G$ weakly of bounded rank if the radical $rad(G)$ has a bounded Pr\\"ufer rank and the index of the sockel of $G/rad(G)$ is bounded. We show that an $\\aleph_{0}$-saturated pseudo-(finite weakly of bounded rank) group either contains a nonabelian free group or is nilpotent-by-abelian-by-(uniformly locally finite). We also obtain some relations between this kind of alternatives and amenability.

  10. Effects of host heterogeneity on pathogen diversity and evolution

    DEFF Research Database (Denmark)

    Fleming-Davies, Arietta E; Dukic, Vanja; Andreasen, Viggo;

    2015-01-01

    strategy for the pathogen: a low-transmission, low-variability type can coexist with the high-transmission type favoured by classical non-heterogeneity models. In addition, this tradeoff can help explain the extensive phenotypic variation we observed in field-collected pathogen isolates, in traits...... (Lymantria dispar) larvae. We found that an empirically observed tradeoff between mean transmission rate and variation in transmission, which results from host heterogeneity, promotes long-term coexistence of two pathogen types in simulations of a population model. This tradeoff introduces an alternative...... affecting virus fitness including transmission and environmental persistence. Similar heterogeneity tradeoffs might be a general mechanism promoting phenotypic variation in any pathogen for which hosts vary continuously in susceptibility....

  11. Extracellular DNA as matrix component in microbial biofilms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tolker-Nielsen, Tim

    2010-01-01

    to various persistent infections in humans and animals, and to a variety of complications in industry, where solid–water interfaces occur. Knowledge about the molecular mechanisms involved in biofilm formation is necessary for creating strategies to control biofilms. Recent studies have shown that......Bacteria in nature primarily live in surface-associated communities commonly known as biofilms. Because bacteria in biofilms, in many cases, display tolerance to host immune systems, antibiotics, and biocides, they are often difficult or impossible to eradicate. Biofilm formation, therefore, leads...... extracellular DNA is an important component of the extracellular matrix of microbial biofilms. The present chapter is focussed on extracellular DNA as matrix component in biofilms formed by Pseudomonas aeruginosa as an example from the Gram-negative bacteria, and Streptococcus and Staphylococcus as examples...

  12. Bouncing alternatives to inflation

    CERN Document Server

    Lilley, Marc

    2015-01-01

    Although the inflationary paradigm is the most widely accepted explanation for the current cosmological observations, it does not necessarily correspond to what actually happened in the early stages of our Universe. To decide on this issue, two paths can be followed: first, all the possible predictions it makes must be derived thoroughly and compared with available data, and second, all imaginable alternatives must be ruled out. Leaving the first task to all other contributors of this volume, we concentrate here on the second option, focusing on the bouncing alternatives and their consequences.

  13. Renewable and alternative energy

    CERN Document Server

    Curley, Robert

    2011-01-01

    With growing populations across the world consuming Earth's limited oil and natural gas reserves, the environmental and economic toll of energy dependence becomes an increasingly global concern. The development of renewable forms of energy-solar, wind, water, and geothermal, to name a few-offers alternatives to fossil fuels. Consumers are embracing these new modes of energy delivery and use. This extensive volume examines the possibility of a cleaner and more energy efficient future by detailing the historic and emerging technologies behind some the most promising alternative resources.

  14. Domestic energy alternatives

    International Nuclear Information System (INIS)

    These alternatives include biomass, clean coal, geothermal, hydropower, natural gas, nuclear, solar and photovoltaic, and wind. With the current, volatile situation in the Middle East, this nation's political leaders appear to be left scratching their heads in their attempts to come up with new, sound, energy policies to reduce our dependence on foreign oil. Therefore, the FORTNIGHTLY's editorial staff thought that this might be an opportune time to briefly examine some home-grown and environmentally responsible fuel alternatives to black gold. While some of these electricity-producing technologies are still on the horizon, others are available now

  15. Carp erythrodermatitis: host defense-pathogen interaction.

    OpenAIRE

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the host's defense system. On the other hand, the host's resistance to a bacterial attack depends on its physiological state, the intensity of the bacterial attack and the efficacy of the defense system to neutralize toxins a...

  16. The Astrobiology Matrix and the "Drake Matrix" in Education

    Science.gov (United States)

    Mizser, A.; Kereszturi, A.

    2003-01-01

    We organized astrobiology lectures in the Eotvos Lorand University of Sciences and the Polaris Observatory in 2002. We present here the "Drake matrix" for the comparison of the astrobiological potential of different bodies [1], and astrobiology matrix for the visualization of the interdisciplinary connections between different fields of astrobiology. Conclusion: In Hungary it is difficult to integrate astrobiology in the education system but the great advantage is that it can connect different scientific fields and improve the view of students. We would like to get in contact with persons and organizations who already have experience in the education of astrobiology.

  17. A survey of matrix theory and matrix inequalities

    CERN Document Server

    Marcus, Marvin

    2010-01-01

    Written for advanced undergraduate students, this highly regarded book presents an enormous amount of information in a concise and accessible format. Beginning with the assumption that the reader has never seen a matrix before, the authors go on to provide a survey of a substantial part of the field, including many areas of modern research interest.Part One of the book covers not only the standard ideas of matrix theory, but ones, as the authors state, ""that reflect our own prejudices,"" among them Kronecker products, compound and induced matrices, quadratic relations, permanents, incidence

  18. Matrix factorizations and elliptic fibrations

    Science.gov (United States)

    Omer, Harun

    2016-09-01

    I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU (5) fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.

  19. Octonionic matrix representation and electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Chanyal, B. C. [Kumaun University, S. S. J. Campus, Almora (India)

    2014-12-15

    Keeping in mind the important role of octonion algebra, we have obtained the electromagnetic field equations of dyons with an octonionic 8 x 8 matrix representation. In this paper, we consider the eight - dimensional octonionic space as a combination of two (external and internal) four-dimensional spaces for the existence of magnetic monopoles (dyons) in a higher-dimensional formalism. As such, we describe the octonion wave equations in terms of eight components from the 8 x 8 matrix representation. The octonion forms of the generalized potential, fields and current source of dyons in terms of 8 x 8 matrix are discussed in a consistent manner. Thus, we have obtained the generalized Dirac-Maxwell equations of dyons from an 8x8 matrix representation of the octonion wave equations in a compact and consistent manner. The generalized Dirac-Maxwell equations are fully symmetric Maxwell equations and allow for the possibility of magnetic charges and currents, analogous to electric charges and currents. Accordingly, we have obtained the octonionic Dirac wave equations in an external field from the matrix representation of the octonion-valued potentials of dyons.

  20. Matrix factorizations and elliptic fibrations

    Directory of Open Access Journals (Sweden)

    Harun Omer

    2016-09-01

    Full Text Available I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU(5 fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.

  1. Modified host cells with efflux pumps

    Energy Technology Data Exchange (ETDEWEB)

    Dunlop, Mary J.; Keasling, Jay D.; Mukhopadhyay, Aindrila

    2016-08-30

    The present invention provides for a modified host cell comprising a heterologous expression of an efflux pump capable of transporting an organic molecule out of the host cell wherein the organic molecule at a sufficiently high concentration reduces the growth rate of or is lethal to the host cell.

  2. Carp erythrodermatitis: host defense-pathogen interaction.

    NARCIS (Netherlands)

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the host's defense syste

  3. Host response mechanisms in periodontal diseases

    Science.gov (United States)

    SILVA, Nora; ABUSLEME, Loreto; BRAVO, Denisse; DUTZAN, Nicolás; GARCIA-SESNICH, Jocelyn; VERNAL, Rolando; HERNÁNDEZ, Marcela; GAMONAL, Jorge

    2015-01-01

    Periodontal diseases usually refer to common inflammatory disorders known as gingivitis and periodontitis, which are caused by a pathogenic microbiota in the subgingival biofilm, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola that trigger innate, inflammatory, and adaptive immune responses. These processes result in the destruction of the tissues surrounding and supporting the teeth, and eventually in tissue, bone and finally, tooth loss. The innate immune response constitutes a homeostatic system, which is the first line of defense, and is able to recognize invading microorganisms as non-self, triggering immune responses to eliminate them. In addition to the innate immunity, adaptive immunity cells and characteristic cytokines have been described as important players in the periodontal disease pathogenesis scenario, with a special attention to CD4+ T-cells (T-helper cells). Interestingly, the T cell-mediated adaptive immunity development is highly dependent on innate immunity-associated antigen presenting cells, which after antigen capture undergo into a maturation process and migrate towards the lymph nodes, where they produce distinct patterns of cytokines that will contribute to the subsequent polarization and activation of specific T CD4+ lymphocytes. Skeletal homeostasis depends on a dynamic balance between the activities of the bone-forming osteoblasts (OBLs) and bone-resorbing osteoclasts (OCLs). This balance is tightly controlled by various regulatory systems, such as the endocrine system, and is influenced by the immune system, an osteoimmunological regulation depending on lymphocyte- and macrophage-derived cytokines. All these cytokines and inflammatory mediators are capable of acting alone or in concert, to stimulate periodontal breakdown and collagen destruction via tissue-derived matrix metalloproteinases, a characterization of the progression of periodontitis as a stage that

  4. Host response mechanisms in periodontal diseases

    Directory of Open Access Journals (Sweden)

    Nora SILVA

    2015-06-01

    Full Text Available Periodontal diseases usually refer to common inflammatory disorders known as gingivitis and periodontitis, which are caused by a pathogenic microbiota in the subgingival biofilm, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola that trigger innate, inflammatory, and adaptive immune responses. These processes result in the destruction of the tissues surrounding and supporting the teeth, and eventually in tissue, bone and finally, tooth loss. The innate immune response constitutes a homeostatic system, which is the first line of defense, and is able to recognize invading microorganisms as non-self, triggering immune responses to eliminate them. In addition to the innate immunity, adaptive immunity cells and characteristic cytokines have been described as important players in the periodontal disease pathogenesis scenario, with a special attention to CD4+ T-cells (T-helper cells. Interestingly, the T cell-mediated adaptive immunity development is highly dependent on innate immunity-associated antigen presenting cells, which after antigen capture undergo into a maturation process and migrate towards the lymph nodes, where they produce distinct patterns of cytokines that will contribute to the subsequent polarization and activation of specific T CD4+ lymphocytes. Skeletal homeostasis depends on a dynamic balance between the activities of the bone-forming osteoblasts (OBLs and bone-resorbing osteoclasts (OCLs. This balance is tightly controlled by various regulatory systems, such as the endocrine system, and is influenced by the immune system, an osteoimmunological regulation depending on lymphocyte- and macrophage-derived cytokines. All these cytokines and inflammatory mediators are capable of acting alone or in concert, to stimulate periodontal breakdown and collagen destruction via tissue-derived matrix metalloproteinases, a characterization of the progression of periodontitis as

  5. Compensated pulsed alternator

    International Nuclear Information System (INIS)

    This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak output. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit

  6. Alternatives to Violence.

    Science.gov (United States)

    Children Today, 1994

    1994-01-01

    Notes that our capacity to diffuse conflict rests in our ability to recognize and verbalize feelings, develop empathy, and think of alternatives to violence. Explores the influence of role models and culture on violence and how the media can use violent images effectively in helping us confront a culture of violence. (HTH)

  7. Tracking alternative energy sources

    International Nuclear Information System (INIS)

    This is the third and last article dealing with global energy topics analyzed at the 13th World Energy Congress. The varied particality or applicability of the following alternative energy sources is briefly discussed at a popular level: fusion, solar, ocean thermal energy conversion, waves, winds, tidal, and geothermal

  8. Alternatives to Blood Transfusion

    Science.gov (United States)

    ... saved articles window. My Saved Articles » My ACS » Blood Transfusion and Donation + - Text Size Download Printable Version [PDF] » TOPICS Document ... Possible risks of blood transfusions Alternatives to blood transfusions Donating blood Blood donation by cancer survivors To learn more References Previous ...

  9. Alternative health insurance schemes

    DEFF Research Database (Denmark)

    Keiding, Hans; Hansen, Bodil O.

    2002-01-01

    In this paper, we present a simple model of health insurance with asymmetric information, where we compare two alternative ways of organizing the insurance market. Either as a competitive insurance market, where some risks remain uninsured, or as a compulsory scheme, where however, the level...

  10. TWTF design alternates

    International Nuclear Information System (INIS)

    The Transuranic Waste Treatment Facility (TWTF) will process transuranic (TRU) waste in retrievable storage at the Idaho National Engineering Laboratory (INEL). The costs for a TWTF concept using a slagging pyrolysis incinerator were excessive. Alternate concepts using a slow speed shredder, a rotary kiln incinerator, and concrete immobilization should result in significant cost reductions. These will be included in future TWTF considerations

  11. Alternative and Integrative Medicine

    Science.gov (United States)

    ... are the healthcare rituals practiced by a given culture (eg, Asian, Indian, African). Homeopathic Medicine: This alternative medicine system is based on the principle that “like cures like.” In other words, the same substance ... American Brain Tumor Association 8550 W. Bryn Mawr Ave. ...

  12. Quasars and their host galaxies

    OpenAIRE

    Lacy, Mark

    2006-01-01

    This review attempts to describe developments in the fields of quasar and quasar host galaxies in the past five. In this time period, the Sloan and 2dF quasar surveys have added several tens of thousands of quasars, with Sloan quasars being found to z>6. Obscured, or partially obscured quasars have begun to be found in significant numbers. Black hole mass estimates for quasars, and our confidence in them, have improved significantly, allowing a start on relating quasar properties such as radi...

  13. Eri silkworm (Samia ricini), a non-mulberry host system for AcMNPV mediated expression of recombinant proteins.

    Science.gov (United States)

    Hosamani, Madhusudan; Basagoudanavar, Suresh H; Sreenivasa, B P; Inumaru, Shigeki; Ballal, Chandish R; Venkataramanan, Ramamurthy

    2015-12-20

    The baculovirus expression system (BVES) based on Autographa californica nucleopolyhedrovirus (AcMNPV) is widely used for the expression of eukaryotic proteins. Several insect cells/larvae that are permissive to AcMNPV have been routinely used as hosts to express heterologous proteins. Domesticated Eri silkworm (Samia ricini), reared in many parts of India, Japan and China, is a non-mulberry silkworm. The present study shows that the Eri silkworm larvae are susceptible to intra-haemocoelical inoculation of AcMNPV. The virus replicates in the larva, as indicated by an increased viral loads in the haemolymph upon injection of a recombinant AcMNPV carrying green fluorescent protein gene. The virus showed localized replication in different tissues including the fat body, haemocytes, tracheal matrix and in the Malphigian tubules. The larval system was successfully used to express heterologous protein, by infecting with a recombinant AcMNPV carrying the 3ABC coding sequence of foot-and-mouth disease virus (FMDV). The study shows that the Eri silkworm larva can be a potential alternative bioreactor, for scaling up of the recombinant proteins employing the baculovirus system. PMID:26467714

  14. Body sizes of hosts and parasitoids in individual feeding relationships

    OpenAIRE

    Joel E. Cohen; Jonsson, Tomas; Müller, Christine B.; Godfray, H. C. J.; Savage, M

    2005-01-01

    In a natural community of 49 species (12 species of aphids and 37 species of their parasitoids), body lengths of 2,151 parasitoid individuals were, to an excellent approximation, related to the body lengths of their individual aphid hosts by a power law with an exponent close to 3/4. Two alternative models predict this exponent. One is based on surface area to volume relationships. The other is based on recent developments in metabolic ecology. Both models require a changing ratio (in both ho...

  15. Parallel R-matrix computation

    International Nuclear Information System (INIS)

    For almost thirty years, sequential R-matrix computation has been used by atomic physics research groups, from around the world, to model collision phenomena involving the scattering of electrons or positrons with atomic or molecular targets. As considerable progress has been made in the understanding of fundamental scattering processes, new data, obtained from more complex calculations, is of current interest to experimentalists. Performing such calculations, however, places considerable demands on the computational resources to be provided by the target machine, in terms of both processor speed and memory requirement. Indeed, in some instances the computational requirements are so great that the proposed R-matrix calculations are intractable, even when utilising contemporary classic supercomputers. Historically, increases in the computational requirements of R-matrix computation were accommodated by porting the problem codes to a more powerful classic supercomputer. Although this approach has been successful in the past, it is no longer considered to be a satisfactory solution due to the limitations of current (and future) Von Neumann machines. As a consequence, there has been considerable interest in the high performance multicomputers, that have emerged over the last decade which appear to offer the computational resources required by contemporary R-matrix research. Unfortunately, developing codes for these machines is not as simple a task as it was to develop codes for successive classic supercomputers. The difficulty arises from the considerable differences in the computing models that exist between the two types of machine and results in the programming of multicomputers to be widely acknowledged as a difficult, time consuming and error-prone task. Nevertheless, unless parallel R-matrix computation is realised, important theoretical and experimental atomic physics research will continue to be hindered. This thesis describes work that was undertaken in

  16. The noncommutative S-Matrix

    Science.gov (United States)

    Raju, Suvrat

    2009-06-01

    As a simple example of how recently developed on-shell techniques apply to nonlocal theories, we study the S-matrix of noncommutative gauge theories. In the complex plane, this S-matrix has essential singularities that signal the nonlocal behavior of the theory. In spite of this, we show that tree-level amplitudes may be obtained by BCFW type recursion relations. At one loop we find a complete basis of master integrals (this basis is larger than the corresponding basis in the ordinary theory). Any one-loop noncommutative amplitude may be written as a linear combination of these integrals with coefficients that we relate to products of tree amplitudes. We show that the noncommutative Script N = 4 SYM theory has a structurally simple S-matrix, just like the ordinary Script N = 4 SYM theory.

  17. Extracellular matrix in ovarian follicles.

    Science.gov (United States)

    Rodgers, R J; Irving-Rodgers, H F; van Wezel, I L

    2000-05-25

    A lot is known about the control of the development of ovarian follicles by growth factors and hormones, but less is known about the roles of extracellular matrix in the control of follicular growth and development. In this review we focus on the specialized extracellular matrix of the basal laminas that are present in ovarian follicles. These include the follicular basal lamina itself, the Call-Exner bodies of the membrana granulosa, the subendothelial and arteriole smooth muscle basal laminas in the theca, and the basal lamina-like material of the thecal matrix. We discuss the evidence that during follicle development the follicular basal lamina changes in composition, that many of its components are produced by the granulosa cells, and that the follicular basal laminas of different follicles have different ultrastructural appearances, linked to the shape of the aligning granulosa cells. All these studies suggest that the follicular basal lamina is extremely dynamic during follicular development. PMID:10963877

  18. A framework program for the teaching of alternative methods (replacement, reduction, refinement) to animal experimentation

    OpenAIRE

    Daneshian, Mardas; Akbarsha, Mohammad A.; Blaauboer, Bas; Caloni, Francesca; Cosson, Pierre; Curren, Rodger; Goldberg, Alan; Gruber, Franz; Ohl, Frauke; Pfaller, Walter; Van der Valk, Jan; Vinardell, Pilar; Zurlo, Joanne; Hartung, Thomas; Leist, Marcel

    2011-01-01

    Development of improved communication and education strategies is important to make alternatives to the use of animals, and the broad range of applications of the 3Rs concept better known and understood by different audiences. For this purpose, the Center for Alternatives to Animal Testing in Europe (CAAT-Europe) together with the Transatlantic Think Tank for Toxicology (t(4)) hosted a three-day workshop on "Teaching Alternative Methods to Animal Experimentation". A compilation of the recomme...

  19. Effect of aligned carbon nanotubes on electrical conductivity behaviour in polycarbonate matrix

    Indian Academy of Sciences (India)

    M M Larijani; E J Khamse; Z Asadollahi; M Asadi

    2012-06-01

    This article reports effects of alignment of embedded carbon nanotubes in a polycarbonate polymer matrix under magnetic, direct and alternating current electric fields on the electrical properties of the resulting nanocomposites. Composites consisting of different quantities of carbon nanotubes in a polycarbonate matrix have been prepared using a solution casting technique. The effects of field strength and nanotube concentration on the resulted network structure and conductivity of the composites were studied by in situ optical microscopy, transmission electron microscopy and four-point probe technique. The results showed that the composites prepared in the presence of field had better conductivity than those of as-prepared composites. It was also concluded that the application of alternating current electric field and magnetic field in this system led to the formation of relatively continuing networks while direct current electric field only prevented agglomeration of the carbon nanotubes in the polycarbonate matrix and created relatively uniform distribution of nanotubes in the matrix.

  20. Matrix model approach to cosmology

    Science.gov (United States)

    Chaney, A.; Lu, Lei; Stern, A.

    2016-03-01

    We perform a systematic search for rotationally invariant cosmological solutions to toy matrix models. These models correspond to the bosonic sector of Lorentzian Ishibashi, Kawai, Kitazawa and Tsuchiya (IKKT)-type matrix models in dimensions d less than ten, specifically d =3 and d =5 . After taking a continuum (or commutative) limit they yield d -1 dimensional Poisson manifolds. The manifolds have a Lorentzian induced metric which can be associated with closed, open, or static space-times. For d =3 , we obtain recursion relations from which it is possible to generate rotationally invariant matrix solutions which yield open universes in the continuum limit. Specific examples of matrix solutions have also been found which are associated with closed and static two-dimensional space-times in the continuum limit. The solutions provide for a resolution of cosmological singularities, at least within the context of the toy matrix models. The commutative limit reveals other desirable features, such as a solution describing a smooth transition from an initial inflation to a noninflationary era. Many of the d =3 solutions have analogues in higher dimensions. The case of d =5 , in particular, has the potential for yielding realistic four-dimensional cosmologies in the continuum limit. We find four-dimensional de Sitter d S4 or anti-de Sitter AdS4 solutions when a totally antisymmetric term is included in the matrix action. A nontrivial Poisson structure is attached to these manifolds which represents the lowest order effect of noncommutativity. For the case of AdS4 , we find one particular limit where the lowest order noncommutativity vanishes at the boundary, but not in the interior.

  1. Polychoric/Tetrachoric Matrix or Pearson Matrix? A methodological study

    Directory of Open Access Journals (Sweden)

    Dominguez Lara, Sergio Alexis

    2014-04-01

    Full Text Available The use of product-moment correlation of Pearson is common in most studies in factor analysis in psychology, but it is known that this statistic is only applicable when the variables related are in interval scale and normally distributed, and when are used in ordinal data may to produce a distorted correlation matrix . Thus is a suitable option using polychoric/tetrachoric matrices in item-level factor analysis when the items are in level measurement nominal or ordinal. The aim of this study was to show the differences in the KMO, Bartlett`s Test and Determinant of the Matrix, percentage of variance explained and factor loadings in depression trait scale of Depression Inventory Trait - State and the Neuroticism dimension of the short form of the Eysenck Personality Questionnaire -Revised, regarding the use of matrices polychoric/tetrachoric matrices and Pearson. These instruments was analyzed with different extraction methods (Maximum Likelihood, Minimum Rank Factor Analysis, Unweighted Least Squares and Principal Components, keeping constant the rotation method Promin were analyzed. Were observed differences regarding sample adequacy measures, as well as with respect to the explained variance and the factor loadings, for solutions having as polychoric/tetrachoric matrix. So it can be concluded that the polychoric / tetrachoric matrix give better results than Pearson matrices when it comes to item-level factor analysis using different methods.

  2. Matrix methods applied linear algebra

    CERN Document Server

    Bronson, Richard

    2008-01-01

    Matrix Methods: Applied Linear Algebra, 3e, as a textbook, provides a unique and comprehensive balance between the theory and computation of matrices. The application of matrices is not just for mathematicians. The use by other disciplines has grown dramatically over the years in response to the rapid changes in technology. Matrix methods is the essence of linear algebra and is what is used to help physical scientists; chemists, physicists, engineers, statisticians, and economists solve real world problems.* Applications like Markov chains, graph theory and Leontief Models are placed i

  3. Towards Google matrix of brain

    International Nuclear Information System (INIS)

    We apply the approach of the Google matrix, used in computer science and World Wide Web, to description of properties of neuronal networks. The Google matrix G is constructed on the basis of neuronal network of a brain model discussed in PNAS 105 (2008) 3593. We show that the spectrum of eigenvalues of G has a gapless structure with long living relaxation modes. The PageRank of the network becomes delocalized for certain values of the Google damping factor α. The properties of other eigenstates are also analyzed. We discuss further parallels and similarities between the World Wide Web and neuronal networks.

  4. Inverse Interval Matrix: A Survey

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Farhadsefat, R.

    2011-01-01

    Roč. 22, - (2011), s. 704-719. E-ISSN 1081-3810 R&D Projects: GA ČR GA201/09/1957; GA ČR GC201/08/J020 Institutional research plan: CEZ:AV0Z10300504 Keywords : interval matrix * inverse interval matrix * NP-hardness * enclosure * unit midpoint * inverse sign stability * nonnegative invertibility * absolute value equation * algorithm Subject RIV: BA - General Math ematics Impact factor: 0.808, year: 2010 http://www. math .technion.ac.il/iic/ela/ela-articles/articles/vol22_pp704-719.pdf

  5. Towards Google matrix of brain

    OpenAIRE

    Shepelyansky, D. L.; Zhirov, O. V.

    2010-01-01

    We apply the approach of the Google matrix, used in computer science and World Wide Web, to description of properties of neuronal networks. The Google matrix ${\\bf G}$ is constructed on the basis of neuronal network of a brain model discussed in PNAS {\\bf 105}, 3593 (2008). We show that the spectrum of eigenvalues of ${\\bf G}$ has a gapless structure with long living relaxation modes. The PageRank of the network becomes delocalized for certain values of the Google damping factor $\\alpha$. The...

  6. Staggered weak matrix element miscellany

    International Nuclear Information System (INIS)

    I report on work, done with Rajan Gupta and Greg Kilcup, using staggered fermions to study weak matrix elements in quenched QCD. I give an update on the ΔI = 1/2 rule on matrix elements relevant for ε'. I show results of a study of the dependence of BK on non-leading terms in the chiral expansion. I present our results for BK from quenched calculation at β = 6.4 on 323 x 48 lattices, based on ensemble of 12 configurations. 15 refs., 5 figs

  7. Holomorphic anomaly and matrix models

    CERN Document Server

    Eynard, B; Orantin, Nicolas; Eynard, Bertrand; Marino, Marcos; Orantin, Nicolas

    2007-01-01

    The genus g free energies of matrix models can be promoted to modular invariant, non-holomorphic amplitudes which only depend on the geometry of the classical spectral curve. We show that these non-holomorphic amplitudes satisfy the holomorphic anomaly equations of Bershadsky, Cecotti, Ooguri and Vafa. We derive as well holomorphic anomaly equations for the open string sector. These results provide evidence at all genera for the Dijkgraaf--Vafa conjecture relating matrix models to type B topological strings on certain local Calabi--Yau threefolds.

  8. Solving matrix-effects exploiting the second order advantage in the resolution and determination of eight tetracycline antibiotics in effluent wastewater by modelling liquid chromatography data with multivariate curve resolution-alternating least squares and unfolded-partial least squares followed by residual bilinearization algorithms I. Effect of signal pre-treatment.

    Science.gov (United States)

    De Zan, M M; Gil García, M D; Culzoni, M J; Siano, R G; Goicoechea, H C; Martínez Galera, M

    2008-02-01

    The effect of piecewise direct standardization (PDS) and baseline correction approaches was evaluated in the performance of multivariate curve resolution (MCR-ALS) algorithm for the resolution of three-way data sets from liquid chromatography with diode-array detection (LC-DAD). First, eight tetracyclines (tetracycline, oxytetracycline, chlorotetracycline, demeclocycline, methacycline, doxycycline, meclocycline and minocycline) were isolated from 250 mL effluent wastewater samples by solid-phase extraction (SPE) with Oasis MAX 500 mg/6 mL cartridges and then separated on an Aquasil C18 150 mm x 4.6mm (5 microm particle size) column by LC and detected by DAD. Previous experiments, carried out with Milli-Q water samples, showed a considerable loss of the most polar analytes (minocycline, oxitetracycline and tetracycline) due to breakthrough. PDS was applied to overcome this important drawback. Conversion of chromatograms obtained from standards prepared in solvent was performed obtaining a high correlation with those corresponding to the real situation (r2 = 0.98). Although the enrichment and clean-up steps were carefully optimized, the sample matrix caused a large baseline drift, and also additive interferences were present at the retention times of the analytes. These problems were solved with the baseline correction method proposed by Eilers. MCR-ALS was applied to the corrected and uncorrected three-way data sets to obtain spectral and chromatographic profiles of each tetracycline, as well as those corresponding to the co-eluting interferences. The complexity of the calibration model built from uncorrected data sets was higher, as expected, and the quality of the spectral and chromatographic profiles was worse. PMID:18093603

  9. The host and the flora.

    Science.gov (United States)

    Nuding, S; Antoni, L; Stange, E F

    2013-01-01

    To prevent bacterial overgrowth, colonization of the epithelium and subsequent translocation, the gastrointestinal tract maintains an effective mucosal barrier. Besides mucus the most important components of this protective system are epithelial antimicrobial peptides such as defensins, the cathelicidin LL-37, lysozyme, phospholipase A, and proteins with additional antimicrobial properties such as ubiquicidin, ribosomal proteins or histones. Commensal species may tolerate intestinal antimicrobial peptides, for example Bacteroides ssp. or Parabacteroides ssp. as major species in the human colon were highly resistant to the constitutive defensin HBD-1 and only susceptible to the inducible defensin HBD-3. Reduction of disulfide bonds is an important mechanism activating HBD-1. As several studies show, alterations in the expression of antimicrobial peptides directly influence the composition of the intestinal flora. Correspondingly, an increased production of defensins or inhibition of the processing of mouse defensins to their active form led to a quantitative shift of luminal and mucosal bacterial species. On the other hand, microorganisms also modulate the synthesis of host defensins by induction or inhibition of specific peptides. Lactobacilli, the probiotic strain Escherichia coli Nissle and Salmonella enteritica stimulate HBD-2 expression, whereas Shigella flexneri downregulates the synthesis of HBD-1, HBD-3 and LL-37. Thus, the proper balance between the luminal flora and the mucosa is a permanently dynamic, sensitive and host-specific relationship. PMID:24246976

  10. Winds of Planet Hosting Stars

    CERN Document Server

    Nicholson, B A; Brookshaw, L; Vidotto, A A; Carter, B D; Marsden, S C; Soutter, J; Waite, I A; Horner, J

    2015-01-01

    The field of exoplanetary science is one of the most rapidly growing areas of astrophysical research. As more planets are discovered around other stars, new techniques have been developed that have allowed astronomers to begin to characterise them. Two of the most important factors in understanding the evolution of these planets, and potentially determining whether they are habitable, are the behaviour of the winds of the host star and the way in which they interact with the planet. The purpose of this project is to reconstruct the magnetic fields of planet hosting stars from spectropolarimetric observations, and to use these magnetic field maps to inform simulations of the stellar winds in those systems using the Block Adaptive Tree Solar-wind Roe Upwind Scheme (BATS-R-US) code. The BATS-R-US code was originally written to investigate the behaviour of the Solar wind, and so has been altered to be used in the context of other stellar systems. These simulations will give information about the velocity, pressur...

  11. Host defences against Giardia lamblia.

    Science.gov (United States)

    Lopez-Romero, G; Quintero, J; Astiazarán-García, H; Velazquez, C

    2015-08-01

    Giardia spp. is a protozoan parasite that inhabits the upper small intestine of mammals and other species and is the aetiological agent of giardiasis. It has been demonstrated that nitric oxide, mast cells and dendritic cells are the first line of defence against Giardia. IL-6 and IL-17 play an important role during infection. Several cytokines possess overlapping functions in regulating innate and adaptive immune responses. IgA and CD4(+) T cells are fundamental to the process of Giardia clearance. It has been suggested that CD4(+) T cells play a double role during the anti-Giardia immune response. First, they activate and stimulate the differentiation of B cells to generate Giardia-specific antibodies. Second, they act through a B-cell-independent mechanism that is probably mediated by Th17 cells. Several Giardia proteins that stimulate humoral and cellular immune responses have been described. Variant surface proteins, α-1 giardin, and cyst wall protein 2 can induce host protective responses to future Giardia challenges. The characterization and evaluation of the protective potential of the immunogenic proteins that are associated with Giardia will offer new insights into host-parasite interactions and may aid in the development of an effective vaccine against the parasite. PMID:26072999

  12. Gut Microbiome-Brain Communications Regulate Host Physiology and Behavior

    Directory of Open Access Journals (Sweden)

    Claire B. de La Serre

    2015-04-01

    Full Text Available The human gut microbiota contains more than 100 trillion bacteria that, under normal physiological conditions, have beneficial symbiotic interactions with the host. However, a growing body of evidence has shown that alternations in the composition and diversity of the gut microbiota, or dysbiosis, can influence the development and progress of metabolic and neurological disorders. Communication between the microbiota and the brain is a bidirectional system involving endocrine, metabolic (bacterial components and metabolites, immune, and neural pathways. Gut microbiota composition influences the signals transmitted from the gut to the brain. Alternatively, the brain utilizes similar mechanisms, in particular endocrine and neural signaling, to modulate the composition of the gut bacteria. In this review, we describe the recent evidence of gut microbiota interaction with the central nervous system to influence physiological and cognitive functions and the therapeutic potential of modulation of the gut microbiota composition.

  13. Properties of the matrix A-XY

    NARCIS (Netherlands)

    Steerneman, A.G.M.; van Perlo -ten Kleij, Frederieke

    2005-01-01

    The main topic of this paper is the matrix V = A - XY*, where A is a nonsingular complex k x k matrix and X and Y are k x p complex matrices of full column rank. Because properties of the matrix V can be derived from those of the matrix Q = I - XY*, we will consider in particular the case where A =

  14. Symmetries and Interactions in Matrix String Theory

    NARCIS (Netherlands)

    F.H. Hacquebord

    1999-01-01

    This PhD-thesis reviews matrix string theory and recent developments therein. The emphasis is put on symmetries, interactions and scattering processes in the matrix model. We start with an introduction to matrix string theory and a review of the orbifold model that flows out of matrix string theory

  15. Display Sharing: An Alternative Paradigm

    Science.gov (United States)

    Brown, Michael A.

    2010-01-01

    The current Johnson Space Center (JSC) Mission Control Center (MCC) Video Transport System (VTS) provides flight controllers and management the ability to meld raw video from various sources with telemetry to improve situational awareness. However, maintaining a separate infrastructure for video delivery and integration of video content with data adds significant complexity and cost to the system. When considering alternative architectures for a VTS, the current system's ability to share specific computer displays in their entirety to other locations, such as large projector systems, flight control rooms, and back supporting rooms throughout the facilities and centers must be incorporated into any new architecture. Internet Protocol (IP)-based systems also support video delivery and integration. IP-based systems generally have an advantage in terms of cost and maintainability. Although IP-based systems are versatile, the task of sharing a computer display from one workstation to another can be time consuming for an end-user and inconvenient to administer at a system level. The objective of this paper is to present a prototype display sharing enterprise solution. Display sharing is a system which delivers image sharing across the LAN while simultaneously managing bandwidth, supporting encryption, enabling recovery and resynchronization following a loss of signal, and, minimizing latency. Additional critical elements will include image scaling support, multi -sharing, ease of initial integration and configuration, integration with desktop window managers, collaboration tools, host and recipient controls. This goal of this paper is to summarize the various elements of an IP-based display sharing system that can be used in today's control center environment.

  16. Dielectrophoresis in particle confinement: Aligned carbon particles in polymer matrix below percolation threshold

    Science.gov (United States)

    Knaapila, M.; Høyer, H.; Helgesen, G.

    2014-09-01

    We review preparation and properties of confined, aligned string-like particle assemblies formed by dielectrophoresis under alternating electric fields. Particular attention is placed on carbon particles aligned in the oligomer matrix. In these systems the particle fraction is low, below the isotropic percolation threshold. The matrix is polymerized after alignment, which locks the aligned strings in place. Application examples are discussed including particle separation, conductivity enhancement and piezoresistive sensors.

  17. The symmetric N-matrix completion problem

    OpenAIRE

    Araújo, C. Mendes; Juan R. Torregrosa; Urbano, Ana M.

    2005-01-01

    An $n\\times n$ matrix is called an $N$-matrix if all its principal minors are negative. In this paper, we are interested in the symmetric $N$-matrix completion problem, that is, when a partial symmetric $N$-matrix has a symmetric $N$-matrix completion. Here, we prove that a partial symmetric $N$-matrix has a symmetric $N$-matrix completion if the graph of its specified entries is chordal. Furthermore, if this graph is not chordal, then examples exist without symmetric $N$...

  18. Evolution of host range in Coleosporium ipomoeae, a plant pathogen with multiple hosts.

    Science.gov (United States)

    Chappell, Thomas M; Rausher, Mark D

    2016-05-10

    Plants and their pathogens coevolve locally. Previous investigations of one host-one pathogen systems have demonstrated that natural selection favors pathogen genotypes that are virulent on a broad range of host genotypes. In the present study, we examine a system consisting of one pathogen species that infects three host species in the morning glory genus Ipomoea. We show that many pathogen genotypes can infect two or three of the host species when tested on plants from nonlocal communities. By contrast, pathogen genotypes are highly host-specific, infecting only one host species, when tested on host species from the local community. This pattern indicates that within-community evolution narrows the host breadth of pathogen genotypes. Possible evolutionary mechanisms include direct selection for narrow host breadth due to costs of virulence and evolution of ipomoea resistance in the host species. PMID:27114547

  19. Independent and competing disease risks: Implications for host Populations in variable environments

    NARCIS (Netherlands)

    Jolles, A.E.; Etienne, R.S.

    2006-01-01

    Disease models usually assume disease to act independently of other mortality- and morbidity-causing factors. Alternatively, disease may function as a competing risk factor, for example, killing already moribund hosts. Using tuberculosis (TB) in African buffalo as a model system, we explore conseque

  20. Independent and competing disease risks : Implications for host Populations in variable environments

    NARCIS (Netherlands)

    Jolles, AE; Etienne, RS; Olff, H; Jolles, Anna E.; DeAngelis, Donald L.; Michalakis, Yannis

    2006-01-01

    Disease models usually assume disease to act independently of other mortality- and morbidity-causing factors. Alternatively, disease may function as a competing risk factor, for example, killing already moribund hosts. Using tuberculosis (TB) in African buffalo as a model system, we explore conseque

  1. [Alternatives to animal testing].

    Science.gov (United States)

    Fabre, Isabelle

    2009-11-01

    The use of alternative methods to animal testing are an integral part of the 3Rs concept (refine, reduce, replace) defined by Russel & Burch in 1959. These approaches include in silico methods (databases and computer models), in vitro physicochemical analysis, biological methods using bacteria or isolated cells, reconstructed enzyme systems, and reconstructed tissues. Emerging "omic" methods used in integrated approaches further help to reduce animal use, while stem cells offer promising approaches to toxicologic and pathophysiologic studies, along with organotypic cultures and bio-artificial organs. Only a few alternative methods can so far be used in stand-alone tests as substitutes for animal testing. The best way to use these methods is to integrate them in tiered testing strategies (ITS), in which animals are only used as a last resort. PMID:20669543

  2. Outlook for alternative transportation fuels

    Energy Technology Data Exchange (ETDEWEB)

    Gushee, D.E. [Univ. of Illinois, Chicago, IL (United States)

    1996-12-31

    This presentation provides a brief review of regulatory issues and Federal programs regarding alternative fuel use in automobiles. A number of U.S. DOE initiatives and studies aimed at increasing alternative fuels are outlined, and tax incentives in effect at the state and Federal levels are discussed. Data on alternative fuel consumption and alternative fuel vehicle use are also presented. Despite mandates, tax incentives, and programs, it is concluded alternative fuels will have minimal market penetration. 7 refs., 5 tabs.

  3. Host Cell Invasion by Toxoplasma gondii Is Temporally Regulated by the Host Microtubule Cytoskeleton ▿ †

    OpenAIRE

    Sweeney, Kristin R.; Morrissette, Naomi S.; LaChapelle, Stephanie; Blader, Ira J.

    2010-01-01

    Toxoplasma gondii is an obligate intracellular protozoan parasite that invades and replicates within most nucleated cells of warm-blooded animals. The basis for this wide host cell tropism is unknown but could be because parasites invade host cells using distinct pathways and/or repertoires of host factors. Using synchronized parasite invasion assays, we found that host microtubule disruption significantly reduces parasite invasion into host cells early after stimulating parasite invasion but...

  4. Sign Patterns That Allow the Given Matrix

    Institute of Scientific and Technical Information of China (English)

    邵燕灵; 孙良

    2003-01-01

    Let P be a property referring to a real matrix. For a sign pattern A, if there exists a real matrix B in the qualitative class of A such that B has property P, then we say A allows P. Three cases that A allows an M-matrix, an inverse M-matrix and a P0-matrix are considered. The complete characterizations are obtained.

  5. ALTERNATIVE DISPUTE RESOLUTION

    Directory of Open Access Journals (Sweden)

    Mihaela Irina IONESCU

    2015-12-01

    Full Text Available Alternative dispute resolution (ADR includes dispute resolution processes and techniques that act as a means for disagreeing parties to come to an agreement short of litigation. It is a collective term for the ways that parties can settle disputes, with (or without the help of a third party.Despite historic resistance to ADR by many popular parties and their advocates, ADR has gained widespread acceptance among both the general public and the legal profession in recent years. In fact, some courts now require some parties to resort to ADR of some type, before permitting the parties' cases to be tried. The rising popularity of ADR can be explained by the increasing caseload of traditional courts, the perception that ADR imposes fewer costs than litigation, a preference for confidentiality, and the desire of some parties to have greater control over the selection of the individual or individuals who will decide their dispute.Directive 2013/11/EU of the European Parliament and of the Council on alternative dispute resolution for consumer disputes and amending Regulation (EC No 2006/2004 and Directive 2009/22/EC (hereinafter „Directive 2013/11/EU” aims to ensure a high level of consumer protection and the proper functioning of the internal market by ensuring that complaints against traders can be submitted by consumers on a voluntary basis, to entities of alternative disputes which are independent, impartial, transparent, effective, simple,quick and fair.Directive 2013/11/EU establishes harmonized quality requirements for entities applying alternative dispute resolution procedure (hereinafter "ADR entity" to provide the same protection and the same rights of consumers in all Member States.Besides this, the present study is trying to present broadly how are all this trasposed in the romanian legislation.

  6. Alternatives to ECMO.

    OpenAIRE

    Donn, S M

    1994-01-01

    The past decade has witnessed technological advancements which are unparalleled in neonatology. ECMO has been demonstrated to be a powerful rescue treatment, but has perhaps been overutilised and is not universally available. Alternative treatments have been shown to be both safe and efficacious in the management of infants with respiratory failure. Direct head to head clinical trials will probably be necessary to establish appropriate criteria and indications for use, given the wide diversit...

  7. Alternative approaches in IVF

    OpenAIRE

    Fauser, Bart; Bouchard, P.; Coelingh Bennink, H.J.; Collins, John; Devroey, P.; Evers, Johannes; Van Steirteghem, A

    2002-01-01

    textabstractVarious new developments in clinical and basic science which may impact on IVF in the near or distant future will be discussed in this review. These key areas include the regulation of early follicle development and the extended in-vitro culture of oocytes and embryos. Moreover, alternative compounds and ovarian stimulation protocols will be discussed, along with highlights in the development of the cryopreservation of excess oocytes or embryos. Finally, the health economics of IV...

  8. Alternative Dispute Resolution

    OpenAIRE

    Mihaela Irina IONESCU

    2004-01-01

    Alternative dispute resolution (ADR) includes dispute resolution processes and techniques that act as a means for disagreeing parties to come to an agreement short of litigation. It is a collective term for the ways that parties can settle disputes, with (or without) the help of a third party.Despite historic resistance to ADR by many popular parties and their advocates, ADR has gained widespread acceptance among both the general public and the legal profession in recent years. In fact, some ...

  9. Metamaterials critique and alternatives

    CERN Document Server

    Munk, Ben A

    2009-01-01

    A Convincing and Controversial Alternative Explanation of Metamaterials with a Negative Index of Refraction In a book that will generate both support and controversy, one of the world's foremost authorities on periodic structures addresses several of the current fashions in antenna design-most specifically, the popular subject of double negative metamaterials. Professor Munk provides a comprehensive theoretical electromagnetic investigation of the issues and concludes that many of the phenomena claimed by researchers may be impossible. While denying the existence of negative refractio

  10. Alternatives to Higgs scalars

    International Nuclear Information System (INIS)

    We discuss alternatives to the Higgs Scalar doublet Φ of the minimal standard model. In particular we review technicolor (TC) and extended technicolor (ETC), and show that the threat of flavour changing neutral currents (FCNC's) is avoided by walking TC and/or strongly coupled ETC. The phenomenology of minimal TC and the techni-family is discussed. Finally we consider the possibility that the Higgs doublet Φ is a composite bound state of quarks from the third (or fourth) family

  11. Fixed field alternating gradient

    OpenAIRE

    Machida, Shinji

    2013-01-01

    The concept of a fixed field alternating gradient (FFAG) accelerator was invented in the 1950s. Although many studies were carried out up to the late 1960s, there has been relatively little progress until recently, when it received widespread attention as a type of accelerator suitable for very fast acceleration and for generating high-power beams. In this paper, we describe the principles and design procedure of a FFAG accelerator.

  12. Multivariate Modelling via Matrix Subordination

    DEFF Research Database (Denmark)

    Nicolato, Elisa

    stochastic volatility via time-change is quite ineffective when applied to the multivariate setting. In this work we propose a new class of models, which is obtained by conditioning a multivariate Brownian Motion to a so-called matrix subordinator. The obtained model-class encompasses the vast majority of...

  13. MATRIX FORMULATION OF REAL QUATERNIONS

    OpenAIRE

    Jafari, Mehdi

    2015-01-01

    Real quaternions have been expressed in terms of 4×4 matrices by means of Hamilton operators. These matrices are applied for rotations in Euclidean 4-space, and are determined also a Hamilton motions in E4. We study these matrices and show that the set of these matrices with the group operation of matrix multiplication is Lie group of 6-dimension.

  14. On T-matrix averaging

    International Nuclear Information System (INIS)

    The T-matrix averaging procedure advocated by Burke, Berrington and Sukumar [1981, J. Phys. B. At. Mol. Phys. 14, 289] is demonstrated to hold in a class of soluble models for two different L2 basis expansions. The convergence rates as the bases are extended to completeness are determined. (author)

  15. S matrix for absorptive Hamiltonians

    International Nuclear Information System (INIS)

    The existence of a matrix S such that SS = 1 in the presence of absorption is demonstrated. In the limit a of hermitian Hamiltonian the unitarity conditions SS = 1 is recovered. A dispersion relation for forward scattering is derived and the properties of the reactance matrices K and K are obtained. It is shown that K = K

  16. The COMPADRE Plant Matrix Database

    DEFF Research Database (Denmark)

    2014-01-01

    COMPADRE contains demographic information on hundreds of plant species. The data in COMPADRE are in the form of matrix population models and our goal is to make these publicly available to facilitate their use for research and teaching purposes. COMPADRE is an open-access database. We only request...

  17. Amorphous metal matrix composite ribbons

    International Nuclear Information System (INIS)

    Composite ribbons with amorphous matrix and ceramic (SiC, WC, MoB) particles were produced by modified planar melt flow casting methods. Weldability, abrasive wear and wood sanding examinations were carried out in order to find optimal material and technology for elevated wear resistance and sanding durability. The correlation between structure and composite properties is discussed. (author)

  18. Survey of aluminum matrix composites

    International Nuclear Information System (INIS)

    This is a review of the current stage of development of fiber reinforced Al matrix composites: primary and secondary fabrication, physical and mechanical properties, environmental effects, applications, current and projected costs of raw material and composites, and future developments. Boron and beryllium are among the filament materials. (101 references, 32 fig.) (U.S.)

  19. The Lucas p-matrix

    Science.gov (United States)

    Kuhapatanakul, Kantaphon

    2015-11-01

    In this note, we study the Fibonacci and Lucas p-numbers. We introduce the Lucas p-matrix and companion matrices for the sums of the Fibonacci and Lucas p-numbers to derive some interesting identities of the Fibonacci and Lucas p-numbers.

  20. Hyper-systolic matrix multiplication

    NARCIS (Netherlands)

    Lippert, Th.; Petkov, N.; Palazzari, P.; Schilling, K.

    2001-01-01

    A novel parallel algorithm for matrix multiplication is presented. It is based on a 1-D hyper-systolic processor abstraction. The procedure can be implemented on all types of parallel systems. (C) 2001 Elsevier Science B,V. All rights reserved.

  1. Parallel Sparse Matrix - Vector Product

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd

    This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...

  2. Matrix Representation of Evolving Networks

    International Nuclear Information System (INIS)

    We present the distance matrix evolution for different types of networks:exponential, scale-free and classical random ones. Statistical properties of these matrices are discussed as well as topological features of the networks. Numerical data on the degree and distance distributions are compared with theoretical predictions. (author)

  3. Alternative Fuels: Research Progress

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2013-01-01

    Full Text Available Chapter 1: Pollutant Emissions and Combustion Characteristics of Biofuels and Biofuel/Diesel Blends in Laminar and Turbulent Gas Jet Flames. R. N. Parthasarathy, S. R. Gollahalli Chapter 2: Sustainable Routes for The Production of Oxygenated High-Energy Density Biofuels from Lignocellulosic Biomass. Juan A. Melero, Jose Iglesias, Gabriel Morales, Marta Paniagua Chapter 3: Optical Investigations of Alternative-Fuel Combustion in an HSDI Diesel Engine. T. Huelser, M. Jakob, G. Gruenefeld, P. Adomeit, S. Pischinger Chapter 4: An Insight into Biodiesel Physico-Chemical Properties and Exhaust Emissions Based on Statistical Elaboration of Experimental Data. Evangelos G. Giakoumis Chapter 5: Biodiesel: A Promising Alternative Energy Resource. A.E. Atabani Chapter 6: Alternative Fuels for Internal Combustion Engines: An Overview of the Current Research. Ahmed A. Taha, Tarek M. Abdel-Salam, Madhu Vellakal Chapter 7: Investigating the Hydrogen-Natural Gas Blends as a Fuel in Internal Combustion Engine. ?lker YILMAZ Chapter 8: Conversion of Bus Diesel Engine into LPG Gaseous Engine; Method and Experiments Validation. M. A. Jemni , G. Kantchev , Z. Driss , R. Saaidia , M. S. Abid Chapter 9: Predicting the Combustion Performance of Different Vegetable Oils-Derived Biodiesel Fuels. Qing Shu, ChangLin Yu Chapter 10: Production of Gasoline, Naphtha, Kerosene, Diesel, and Fuel Oil Range Fuels from Polypropylene and Polystyrene Waste Plastics Mixture by Two-Stage Catalytic Degradation using ZnO. Moinuddin Sarker, Mohammad Mamunor Rashid

  4. State alternative route designations

    Energy Technology Data Exchange (ETDEWEB)

    1989-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a ``state routing agency,`` defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective.

  5. State alternative route designations

    Energy Technology Data Exchange (ETDEWEB)

    1989-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a state routing agency,'' defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective.

  6. Is garlic alternative medicine?

    Science.gov (United States)

    Rivlin, Richard S

    2006-03-01

    Garlic has been used medicinally since antiquity. In virtually every early civilization known, such as ancient India, Egypt, Rome, China, and Japan, garlic was part of the therapeutic regimen for a variety of maladies. Therefore, the ancient medicinal tradition of garlic use would qualify it as a folk medicine or as an alternative or complementary medicine. But is garlic an alternative to established methods of disease prevention or treatment? Scientists from around the world have identified a number of bioactive substances in garlic that are water soluble (e.g., S-allyl methylcysteine), and fat soluble (e.g., diallyldisulfide). Mechanisms of action are being elucidated by modern technology. The validity of ancient medicine is now being evaluated critically in cell-free systems, animal models, and human populations. Preventive and therapeutic trials of garlic are still in early stages. There are many promising lines of research suggesting the potential effects of garlic. The current state of knowledge does not recognize garlic as a true alternative, but it will likely find a place for garlic as a complement to established methods of disease prevention and treatment. Our goal should be to examine garlic together with other agents to evaluate its possible efficacy and toxicity under conditions of actual use in humans. PMID:16484549

  7. Alternative Energy Sources

    CERN Document Server

    Michaelides, Efstathios E (Stathis)

    2012-01-01

    Alternative Energy Sources is designed to give the reader, a clear view of the role each form of alternative energy may play in supplying the energy needs of the human society in the near and intermediate future (20-50 years).   The two first chapters on energy demand and supply and environmental effects, set the tone as to why the widespread use of alternative energy is essential for the future of human society. The third chapter exposes the reader to the laws of energy conversion processes, as well as the limitations of converting one energy form to another. The sections on exergy give a succinct, quantitative background on the capability/potential of each energy source to produce power on a global scale. The fourth, fifth and sixth chapters are expositions of fission and fusion nuclear energy. The following five chapters (seventh to eleventh) include detailed descriptions of the most common renewable energy sources – wind, solar, geothermal, biomass, hydroelectric – and some of the less common sources...

  8. Carbon Dots and 9AA as a Binary Matrix for the Detection of Small Molecules by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    Science.gov (United States)

    Chen, Yongli; Gao, Dan; Bai, Hangrui; Liu, Hongxia; Lin, Shuo; Jiang, Yuyang

    2016-07-01

    Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analyze small molecules have some limitations, due to the inhomogeneous analyte/matrix co-crystallization and interference of matrix-related peaks in low m/z region. In this work, carbon dots (CDs) were for the first time applied as a binary matrix with 9-Aminoacridine (9AA) in MALDI MS for small molecules analysis. By 9AA/CDs assisted desorption/ionization (D/I) process, a wide range of small molecules, including nucleosides, amino acids, oligosaccharides, peptides, and anticancer drugs with a higher sensitivity were demonstrated in the positive ion mode. A detection limit down to 5 fmol was achieved for cytidine. 9AA/CDs matrix also exhibited excellent reproducibility compared with 9AA matrix. Moreover, by exploring the ionization mechanism of the matrix, the influence factors might be attributed to the four parts: (1) the strong UV absorption of 9AA/CDs due to their π-conjugated network; (2) the carboxyl groups modified on the CDs surface act as protonation sites for proton transfer in positive ion mode; (3) the thin layer crystal of 9AA/CDs could reach a high surface temperature more easily and lower transfer energy for LDI MS; (4) CDs could serve as a matrix additive to suppress 9AA ionization. Furthermore, this matrix was allowed for the analysis of glucose as well as nucleosides in human urine, and the level of cytidine was quantified with a linear range of 0.05-5 mM (R2 > 0.99). Therefore, the 9AA/CDs matrix was proven to be an effective MALDI matrix for the analysis of small molecules with improved sensitivity and reproducibility. This work provides an alternative solution for small molecules detection that can be further used in complex samples analysis.

  9. Carbon Dots and 9AA as a Binary Matrix for the Detection of Small Molecules by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry.

    Science.gov (United States)

    Chen, Yongli; Gao, Dan; Bai, Hangrui; Liu, Hongxia; Lin, Shuo; Jiang, Yuyang

    2016-07-01

    Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analyze small molecules have some limitations, due to the inhomogeneous analyte/matrix co-crystallization and interference of matrix-related peaks in low m/z region. In this work, carbon dots (CDs) were for the first time applied as a binary matrix with 9-Aminoacridine (9AA) in MALDI MS for small molecules analysis. By 9AA/CDs assisted desorption/ionization (D/I) process, a wide range of small molecules, including nucleosides, amino acids, oligosaccharides, peptides, and anticancer drugs with a higher sensitivity were demonstrated in the positive ion mode. A detection limit down to 5 fmol was achieved for cytidine. 9AA/CDs matrix also exhibited excellent reproducibility compared with 9AA matrix. Moreover, by exploring the ionization mechanism of the matrix, the influence factors might be attributed to the four parts: (1) the strong UV absorption of 9AA/CDs due to their π-conjugated network; (2) the carboxyl groups modified on the CDs surface act as protonation sites for proton transfer in positive ion mode; (3) the thin layer crystal of 9AA/CDs could reach a high surface temperature more easily and lower transfer energy for LDI MS; (4) CDs could serve as a matrix additive to suppress 9AA ionization. Furthermore, this matrix was allowed for the analysis of glucose as well as nucleosides in human urine, and the level of cytidine was quantified with a linear range of 0.05-5 mM (R(2) > 0.99). Therefore, the 9AA/CDs matrix was proven to be an effective MALDI matrix for the analysis of small molecules with improved sensitivity and reproducibility. This work provides an alternative solution for small molecules detection that can be further used in complex samples analysis. Graphical Abstract ᅟ. PMID:27075876

  10. Carbon Dots and 9AA as a Binary Matrix for the Detection of Small Molecules by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    Science.gov (United States)

    Chen, Yongli; Gao, Dan; Bai, Hangrui; Liu, Hongxia; Lin, Shuo; Jiang, Yuyang

    2016-04-01

    Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analyze small molecules have some limitations, due to the inhomogeneous analyte/matrix co-crystallization and interference of matrix-related peaks in low m/z region. In this work, carbon dots (CDs) were for the first time applied as a binary matrix with 9-Aminoacridine (9AA) in MALDI MS for small molecules analysis. By 9AA/CDs assisted desorption/ionization (D/I) process, a wide range of small molecules, including nucleosides, amino acids, oligosaccharides, peptides, and anticancer drugs with a higher sensitivity were demonstrated in the positive ion mode. A detection limit down to 5 fmol was achieved for cytidine. 9AA/CDs matrix also exhibited excellent reproducibility compared with 9AA matrix. Moreover, by exploring the ionization mechanism of the matrix, the influence factors might be attributed to the four parts: (1) the strong UV absorption of 9AA/CDs due to their π-conjugated network; (2) the carboxyl groups modified on the CDs surface act as protonation sites for proton transfer in positive ion mode; (3) the thin layer crystal of 9AA/CDs could reach a high surface temperature more easily and lower transfer energy for LDI MS; (4) CDs could serve as a matrix additive to suppress 9AA ionization. Furthermore, this matrix was allowed for the analysis of glucose as well as nucleosides in human urine, and the level of cytidine was quantified with a linear range of 0.05-5 mM (R2 > 0.99). Therefore, the 9AA/CDs matrix was proven to be an effective MALDI matrix for the analysis of small molecules with improved sensitivity and reproducibility. This work provides an alternative solution for small molecules detection that can be further used in complex samples analysis.

  11. Hermite matrix in Lagrange basis for scaling static output feedback polynomial matrix inequalities

    CERN Document Server

    Delibasi, Akin

    2010-01-01

    Using Hermite's formulation of polynomial stability conditions, static output feedback (SOF) controller design can be formulated as a polynomial matrix inequality (PMI), a (generally nonconvex) nonlinear semidefinite programming problem that can be solved (locally) with PENNON, an implementation of a penalty method. Typically, Hermite SOF PMI problems are badly scaled and experiments reveal that this has a negative impact on the overall performance of the solver. In this note we recall the algebraic interpretation of Hermite's quadratic form as a particular Bezoutian and we use results on polynomial interpolation to express the Hermite PMI in a Lagrange polynomial basis, as an alternative to the conventional power basis. Numerical experiments on benchmark problem instances show the substantial improvement brought by the approach, in terms of problem scaling, number of iterations and convergence behavior of PENNON.

  12. Anonymous Web Browsing and Hosting

    Directory of Open Access Journals (Sweden)

    MANOJ KUMAR

    2013-02-01

    Full Text Available In today’s high tech environment every organization, individual computer users use internet for accessing web data. To maintain high confidentiality and security of the data secure web solutions are required. In this paper we described dedicated anonymous web browsing solutions which makes our browsing faster and secure. Web application which play important role for transferring our secret information including like email need more and more security concerns. This paper also describes that how we can choose safe web hosting solutions and what the main functions are which provides more security over server data. With the browser security network security is also important which can be implemented using cryptography solutions, VPN and by implementing firewalls on the network. Hackers always try to steal our identity and data, they track our activities using the network application software’s and do harmful activities. So in this paper we described that how we can monitor them from security purposes.

  13. A DIRECT ALGORITHM FOR DISTINGUISHING NONSINGULAR M-MATRIX AND H-MATRIX

    Institute of Scientific and Technical Information of China (English)

    Li Yaotang; Zhu Yan

    2005-01-01

    A direct algorithm is proposed by which one can distinguish whether a matrix is an M-matrix (or H-matrix) or not quickly and effectively. Numerical examples show that it is effective and convincible to distinguish M-matrix (or H-matrix) by using the algorithm.

  14. Shifting preference between oviposition vs. host-feeding under changing host densities in two aphelinid parasitoids.

    Directory of Open Access Journals (Sweden)

    Nian-Wan Yang

    Full Text Available Destructive host-feeding is common in hymenopteran parasitoids. Such feeding may be restricted to host stages not preferred for oviposition. However, whether this is a fixed strategy or can vary according to resource levels or parasitoid needs is less clear. We tested the trade-off between host feeding and oviposition on two whitefly parasitoids under varying host densities. Females of two aphelinid parasitoids, Eretmocerus hayati and Encarsia sophia were exposed to nine different densities of their whitefly host, Bemisia tabaci, in single-instar tests to identify their functional response. Mixed-instar host choice tests were also conducted by exposing whiteflies at four densities to the parasitoids. We hypothesized that the parasitoid females can detect different host densities, and decide on oviposition vs. host-feeding accordingly. The results showed that both Er. hayati and En. sophia females tended to increase both oviposition and host-feeding with increased host density within a certain range. Oviposition reached a plateau at lower host density than host-feeding in Er. hayati, while En. sophia reached its oviposition plateau at higher densities. At low densities, Er. hayati parasitized most on first and second (the optimal ones, and fed most on third nymphal instars (the suboptimal one of the whitefly host as theory predicts, while at high densities, both parasitism and host-feeding occurred on first and second instars which are preferred for oviposition. En. sophia parasitized most on third and fourth (the optimal ones, while fed on first instars (the suboptimal one at low densities, and utilized third and fourth instars for both at high densities. In conclusion, oviposition vs. host-feeding strategy of parasitoid females was found to vary at different host densities. The balance between reserving optimal hosts for oviposition or using them for host-feeding depended on parasitoid life history and the availability of host resources.

  15. Pulse-Width-Modulation of Neutral-Point-Clamped Sparse Matrix Converter

    DEFF Research Database (Denmark)

    Loh, P.C.; Blaabjerg, Frede; Gao, F.;

    2007-01-01

    Sparse matrix converter is an alternative "allsemiconductor" energy processor proposed recently for converting an ac source with fixed magnitude and frequency to a variable voltage and frequency supply that can meet the requirements of a particular industry application. In principle, sparse matrix...... input current and output voltage can be achieved with minimized rectification switching loss, rendering the sparse matrix converter as a competitive choice for interfacing the utility grid to (e.g.) defense facilities that require a different frequency supply. As an improvement, sparse matrix converter...... literature. Addressing the afore-described issues, this paper focuses on the operational mode analysis of a three-level sparse matrix converter implemented using a neutral-point-clamped inversion stage, and  the design of a number of PWM and modulation ratio compensation schemes for controlling the converter...

  16. Fibronectin matrix assembly requires distinct contributions from Rho kinases I and -II

    DEFF Research Database (Denmark)

    Yoneda, Atsuko; Ushakov, Dmitriy; Multhaupt, Hinke A B;

    2006-01-01

    , the effect of ROCK I deficiency on fibronectin matrix assembly was secondary to altered cell surface morphology, rich in filopodia, resulting from high GTP-Cdc42 levels. Total internal reflection microscopy revealed that a submembranous pool of myosin light chain in control cells was missing in ROCK II......Extracellular matrix is integral to tissue architecture and regulates many aspects of cell behavior. Fibronectin matrix assembly involves the actin cytoskeleton and the small GTPase RhoA, but downstream signaling is not understood. Here, down-regulation of either rho kinase isoform (ROCK I or -II......) by small interfering RNA treatment blocked fibronectin matrix assembly, although the phenotypes were distinct and despite persistence of the alternate kinase. Remnant fibronectin on ROCK-deficient fibroblasts was mostly punctate and more deoxycholate soluble compared with controls. Fibronectin matrix...

  17. Integrating temperature-dependent life table data into a matrix projection model for Drosophila suzukii population estimation.

    Directory of Open Access Journals (Sweden)

    Nik G Wiman

    Full Text Available Temperature-dependent fecundity and survival data was integrated into a matrix population model to describe relative Drosophila suzukii Matsumura (Diptera: Drosophilidae population increase and age structure based on environmental conditions. This novel modification of the classic Leslie matrix population model is presented as a way to examine how insect populations interact with the environment, and has application as a predictor of population density. For D. suzukii, we examined model implications for pest pressure on crops. As case studies, we examined model predictions in three small fruit production regions in the United States (US and one in Italy. These production regions have distinctly different climates. In general, patterns of adult D. suzukii trap activity broadly mimicked seasonal population levels predicted by the model using only temperature data. Age structure of estimated populations suggest that trap and fruit infestation data are of limited value and are insufficient for model validation. Thus, we suggest alternative experiments for validation. The model is advantageous in that it provides stage-specific population estimation, which can potentially guide management strategies and provide unique opportunities to simulate stage-specific management effects such as insecticide applications or the effect of biological control on a specific life-stage. The two factors that drive initiation of the model are suitable temperatures (biofix and availability of a suitable host medium (fruit. Although there are many factors affecting population dynamics of D. suzukii in the field, temperature-dependent survival and reproduction are believed to be the main drivers for D. suzukii populations.

  18. Dissecting host-associated communities with DNA barcodes.

    Science.gov (United States)

    Baker, Christopher C M; Bittleston, Leonora S; Sanders, Jon G; Pierce, Naomi E

    2016-09-01

    DNA barcoding and metabarcoding methods have been invaluable in the study of interactions between host organisms and their symbiotic communities. Barcodes can help identify individual symbionts that are difficult to distinguish using morphological characters, and provide a way to classify undescribed species. Entire symbiont communities can be characterized rapidly using barcoding and especially metabarcoding methods, which is often crucial for isolating ecological signal from the substantial variation among individual hosts. Furthermore, barcodes allow the evolutionary histories of symbionts and their hosts to be assessed simultaneously and in reference to one another. Here, we describe three projects illustrating the utility of barcodes for studying symbiotic interactions: first, we consider communities of arthropods found in the ant-occupied domatia of the East African ant-plant Vachellia (Acacia) drepanolobium; second, we examine communities of arthropod and protozoan inquilines in three species of Nepenthes pitcher plant in South East Asia; third, we investigate communities of gut bacteria of South American ants in the genus Cephalotes Advances in sequencing and computation, and greater database connectivity, will continue to expand the utility of barcoding methods for the study of species interactions, especially if barcoding can be approached flexibly by making use of alternative genetic loci, metagenomes and whole-genome data.This article is part of the themed issue 'From DNA barcodes to biomes'. PMID:27481780

  19. Tripartite associations among bacteriophage WO, Wolbachia, and host affected by temperature and age in Tetranychus urticae.

    Science.gov (United States)

    Lu, Ming-Hong; Zhang, Kai-Jun; Hong, Xiao-Yue

    2012-11-01

    A phage density model of cytoplasmic incompatibility (CI), which means lytic phages reduce bacterial density associated with CI, significantly enhances our understanding of the tripartite associations among bacteriophage WO, Wolbachia and host. However, WO may alternate between lytic and lysogenic life cycles or change phage production under certain conditions including temperature, host age and host species background. Here, extreme temperatures can induce an alteration in the life cycle of WO and change the tripartite associations among WO, Wolbachia and CI. Based on the accumulation of the WO load, WO can transform into the lytic life cycle with increasing age. These findings confirmed that the environment plays an important role in the associations among WO, Wolbachia and host. PMID:22669278

  20. Cellular immunity and pathogen strategies in combative interactions involving Drosophila hosts and their endoparasitic wasps

    Directory of Open Access Journals (Sweden)

    AJ Nappi

    2010-09-01

    Full Text Available Various cellular innate immune responses protect invertebrates from attack by eukaryotic pathogens. In insects, assessments of the factor(s causing, or contributing to, pathogen mortality have long considered as toxic components certain molecules associated with enzyme-mediated melanogenesis. In Drosophila hosts, observations that have prompted additional or alternative considerations are those that document either the survival of certain endoparasitic wasps despite melanotic encapsulation, or the destruction of the parasite with no evidence of this type of host response. Investigations of the production of some reactive intermediates of oxygen and nitrogen during infection provide a basis for proposing that these molecules constitute important elements of the immune arsenal of Drosophila. Studies of the target specificity of virulence factors injected by female wasps during infection that suppress the host immune response will likely facilitate identification of the toxic host molecules, and contribute to a more detailed understanding of the cell-signaling pathways that regulate their synthesis.

  1. Conditional genome engineering in Toxoplasma gondii uncovers alternative invasion mechanisms

    OpenAIRE

    Andenmatten, Nicole; Egarter, Saskia; Jackson, Allison J.; JULLIEN, Nicolas; Herman, Jean-Paul; Meissner, Markus

    2012-01-01

    We established a conditional site–specific recombination system based on dimerizable Cre–mediated recombination in the apicomplexan parasite Toxoplasma gondii. Using a novel single vector strategy that allows ligand-dependent, efficient removal of a gene of interest, we generated three knockouts of apicomplexan genes considered essential for host-cell invasion. Our findings uncover the existence of an alternative invasion pathway in apicomplexan parasites.

  2. Alternatives to nuclear energy

    International Nuclear Information System (INIS)

    This article discusses several possibilities as alternatives to nuclear energy and their relevance to the Philippine case. The major present and future fuel alternatives to petroleum and nuclear energy are coal, geothermal heat, solar energy and hydrogen, the first two of which are being used. Different conversion technologies are also discussed for large scale electricity production namely solar thermal electric conversion (STC), photovoltaic electric power system (PEPS) and ocean thermal energy conversion (OTEC). Major environmental considerations affect the choice of energy sources and technologies. We have the problem of long term accumulation of radioactive waste in the case of nuclear energy; in geothermal and fossil-fuels carbon dioxide uranium and accumulation may cause disastrous consequences. With regard to Philippine option, the greatest considerations in selecting alternative energy options would be resources availability - both energy and financial and technology status. For the country's energy plan, coal and geothermal energy are expected to play a significant role. The country's coal resources are 1.4 billion metric tons. For geothermal energy, 25 volcanic centers were identified and has a potential equivalent to 2.5 x 106 million barrels of oil. Solar energy if harnessed, being in the sunbelt, averaging some 2000 hours a year could be an energy source. The present dilemma of the policy maker is whether national resources are better spent on large scale urban-based energy projects or whether those should be focused on small scale, rural oriented installations which produced benefits to the more numerous and poorer members of the population. (RTD)

  3. Robust estimation of the correlation matrix of longitudinal data

    KAUST Repository

    Maadooliat, Mehdi

    2011-09-23

    We propose a double-robust procedure for modeling the correlation matrix of a longitudinal dataset. It is based on an alternative Cholesky decomposition of the form Σ=DLL⊤D where D is a diagonal matrix proportional to the square roots of the diagonal entries of Σ and L is a unit lower-triangular matrix determining solely the correlation matrix. The first robustness is with respect to model misspecification for the innovation variances in D, and the second is robustness to outliers in the data. The latter is handled using heavy-tailed multivariate t-distributions with unknown degrees of freedom. We develop a Fisher scoring algorithm for computing the maximum likelihood estimator of the parameters when the nonredundant and unconstrained entries of (L,D) are modeled parsimoniously using covariates. We compare our results with those based on the modified Cholesky decomposition of the form LD2L⊤ using simulations and a real dataset. © 2011 Springer Science+Business Media, LLC.

  4. Alternate fusion concepts

    International Nuclear Information System (INIS)

    This review summarizes the status of alternate fusion concepts and plans for their future. The concepts selected for review are those employing electromagnetic confinement for which there have been reasonable predictions of net energy gain from pure fusion and which have shown significant recent development or are the subjects of ongoing international activity. They include advanced tokamaks, stellarators, the spherical torus, reversed-field pinch and dense z-field pinch devices, field reversed configuration, and spheromaks. In addition, an overall view of the status of each concept with respect to achieving ignition and to reactor designs is presented

  5. Alternate fuels; Combustibles alternos

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes R, Hernando; Ambriz G, Juan Jose [Universidad Autonoma Metropolitana. Iztapalapa (Mexico)

    2003-07-01

    In the definition and description of alternate fuels we must center ourselves in those technological alternatives that allow to obtain compounds that differ from the traditional ones, in their forms to be obtained. In this article it is tried to give an overview of alternate fuels to the conventional derivatives of petroleum and that allow to have a clear idea on the tendencies of modern investigation and the technological developments that can be implemented in the short term. It is not pretended to include all the tendencies and developments of the present world, but those that can hit in a relatively short term, in accordance with agreed with the average life of conventional fuels. Nevertheless, most of the conversion principles are applicable to the spectrum of carbonaceous or cellulosic materials which are in nature, are cultivated or wastes of organic origin. Thus one will approach them in a successive way, the physical, chemical and biological conversions that can take place in a production process of an alternate fuel or the same direct use of the fuel such as burning the sweepings derived from the forests. [Spanish] En la definicion y descripcion de combustibles alternos nos debemos centrar en aquellas alternativas tecnologicas que permitan obtener compuestos que difieren de los tradicionales, al menos en sus formas de ser obtenidos. En este articulo se pretende dar un panorama de los combustibles alternos a los convencionales derivados del petroleo y que permita tener una idea clara sobre las tendencias de la investigacion moderna y los desarrollos tecnologicos que puedan ser implementados en el corto plazo. No se pretende abarcar todas las tendencias y desarrollos del mundo actual, sino aquellas que pueden impactar en un plazo relativamente corto, acordes con la vida media de los combustibles convencionales. Sin embargo, la mayor parte de los principios de conversion son aplicables al espectro de materiales carbonaceos o celulosicos los cuales se

  6. Polyphase alternating codes

    OpenAIRE

    M. Markkanen; Vierinen, J.; Markkanen, J.

    2007-01-01

    We present a new class of alternating codes. Instead of the customary binary phase codes, the new codes utilize either p or p–1 phases, where p is a prime number. The first class of codes has code length pm, where m is a positive integer, the second class has code length p–1. We give an actual construction algorithm, and explain the principles behind it. We ...

  7. Polyphase alternating codes

    Directory of Open Access Journals (Sweden)

    M. Markkanen

    2008-08-01

    Full Text Available We present a new class of alternating codes. Instead of the customary binary phase codes, the new codes utilize either p or p–1 phases, where p is a prime number. The first class of codes has code length pm, where m is a positive integer, the second class has code length p–1. We give an actual construction algorithm, and explain the principles behind it. We handle a few specific examples in detail. The new codes offer an enlarged collection of code lengths for radar experiments.

  8. Alternate transportation system

    Science.gov (United States)

    Zertuche, Tony; Mckinnie, James

    1988-01-01

    Three missions have been identified by NASA for a Space Shuttle-supplementing Alternate Transportation System (ATS) encompassing combinations of booster vehicles, crew modules, and service modules: (1) to achieve manned access to orbit for Space Station crew rotation every 90 days, (2) the lofting of a logistics module resupplying the Space Station every 180 days, and (3) the simultaneous launch of both crews and logistics to the Space Station. A reentry glider is considered, in conjunction with the Space Shuttle's unmanned cargo version and the Apollo manned capsule, as an important ATS element. The Titan IV/NUS is used as a booster.

  9. Gabbro as a host rock for a nuclear waste repository

    International Nuclear Information System (INIS)

    As an alternative to granitic rocks, gabbro and other basic rock types have been investigated with respect to their suitability to host a nuclear waste repository. The present report summarizes and examines existing geoscientific knowledge of relevance in assessing the potential merits of gabbro as a repository host rock. Implications in terms of site selection, repository construction and post-closure repository performance are also discussed. The objective of the study is to provide a basis for decisions as regards future consideration of the gabbro alternative. It is found that there are rather few gabbro bodies in Sweden, that are potentially of sufficient size to host a repository. Thus, gabbro offers little latitude as regards site selection. In comparison to siting a repository in granitic rocks, this is a major disadvantage, and it may in fact remove gabbro from further consideration. The potential advantages of gabbro refer to repository performance, and include low hydraulic conductivity and a chemical environment promoting efficient radionuclide retardation. However, results from field investigations show that groundwater flow in gabbro bodies is largely controlled by intersecting heterogeneities, in particular granitic dykes, that are significantly more conductive to water than the gabbro. In the far-field scale significant to repository performance, this may reduce or eliminate the potential effects of favourable hydraulic and chemical characteristics of the gabbro itself. In conclusion, there are apparent difficulties associated with siting a repository in gabbro, due to lack of sufficiently large gabbro bodies. On the basis of the present state of knowledge, no decisive differences can be demonstrated when comparing gabbro with granitic rocks, neither with respects to repository construction, nor as regards repository performance. (au)

  10. MHC polymorphism under host-pathogen coevolution

    OpenAIRE

    Borghans, J.A.M.; J.B. Beltman; de Boer, R J

    2004-01-01

    The genes encoding major histocompatibility (MHC) molecules are among the most polymorphic genes known for vertebrates. Since MHC molecules play an important role in the induction of immune responses, the evolution of MHC polymorphism is often explained in terms of increased protection of hosts against pathogens. Two selective pressures that are thought to be involved are (1) selection favoring MHC heterozygous hosts, and (2) selection for rare MHC alleles by host-pathogen coevolution. We hav...

  11. Immunological aspects of host-schistosome relationships

    Directory of Open Access Journals (Sweden)

    Raymond T. Damian

    1987-01-01

    Full Text Available The complex immunological relationships between schistosomes and their vertebrate hosts are considered to be conveniently divisible into four distinct, though interrelated categories: the parasite's vulnerability to, its evasion of, and its exploitation of the host's immune response, and its stimulation of the host's immune response to produce immunopathology. Some significant recent advances in the first three categories are discussed, as well as their relationships to the fourth category of immunopathology.

  12. Host manipulation by parasites: a multidimensional phenomenon

    OpenAIRE

    Thomas, F; Poulin, R.; Brodeur, J.

    2010-01-01

    The diversity of ways in which parasites manipulate the phenotype of their hosts to increase their transmission has been well-documented during the past decades. Parasites clearly have the potential to alter a broad range of phenotypic traits in their hosts, extending from behaviour and colour to morphology and physiology. While the vast majority of studies have concentrated on few, often only one, host characters, there is increasing evidence that manipulative parasites alter multiple charac...

  13. Revisiting Caspase-11 Function in Host Defense

    OpenAIRE

    Ng, Tessie M.; Monack, Denise M.

    2013-01-01

    Pro-inflammatory caspases play important roles in innate immunity. Much attention has focused on caspase-1, which acts to eliminate pathogens by obliterating their replicative niches as well as alerting the host to their presence. Emerging data now sheds light on the lesser-studied pro-inflammatory caspase-11 in the combat between host and pathogen. With new tools available, researchers are now further elucidating the mechanisms by which caspase-11 contributes to host defense. Here, we review...

  14. Host defense reinforces host–parasite cospeciation

    OpenAIRE

    Clayton, Dale H.; Bush, Sarah E.; Goates, Brad M.; Johnson, Kevin P.

    2003-01-01

    Cospeciation occurs when interacting groups, such as hosts and parasites, speciate in tandem, generating congruent phylogenies. Cospeciation can be a neutral process in which parasites speciate merely because they are isolated on diverging host islands. Adaptive evolution may also play a role, but this has seldom been tested. We explored the adaptive basis of cospeciation by using a model system consisting of feather lice (Columbicola) and their pigeon and dove hosts (Columbiformes). We recon...

  15. Some considerations of matrix equations using the concept of reproductivity

    OpenAIRE

    Malesevic, Branko; Radicic, Biljana

    2011-01-01

    In this paper we analyse Cline's matrix equation, generalized Penrose's matrix system and a matrix system for k-commutative {1}-inverses. We determine reproductive and non-reproductive general solutions of analysed matrix equation and analysed matrix systems.

  16. The Constrained Solutions of Two Matrix Equations

    Institute of Scientific and Technical Information of China (English)

    An Ping LIAO; Zhong Zhi BAI

    2002-01-01

    We study the symmetric positive semidefinite solution of the matrix equation AX1AT +BX2BT = C, where A is a given real m × n matrix, B is a given real m × p matrix, and C is a givenreal m × m matrix, with m, n, p positive integers; and the bisymmetric positive semidefinite solutionof the matrix equation DTXD = C, where D is a given real n × m matrix, C is a given real m × mmatrix, with m, n positive integers. By making use of the generalized singular value decomposition, wederive general analytic formulae, and present necessary and sufficient conditions for guaranteeing theexistence of these solutions.

  17. Matrix Factorization for Evolution Data

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Huang

    2014-01-01

    Full Text Available We study a matrix factorization problem, that is, to find two factor matrices U and V such that R≈UT×V, where R is a matrix composed of the values of the objects O1,O2,…,On at consecutive time points T1,T2,…,Tt. We first present MAFED, a constrained optimization model for this problem, which straightforwardly performs factorization on R. Then based on the interplay of the data in U, V, and R, a probabilistic graphical model using the same optimization objects is constructed, in which structural dependencies of the data in these matrices are revealed. Finally, we present a fitting algorithm to solve the proposed MAFED model, which produces the desired factorization. Empirical studies on real-world datasets demonstrate that our approach outperforms the state-of-the-art comparison algorithms.

  18. Clustering Assisted Fundamental Matrix Estimation

    Directory of Open Access Journals (Sweden)

    Hao Wu

    2015-03-01

    Full Text Available In computer vision, the estimation of the fundament al matrix is a basic problem that has been extensively studied. The accuracy of the estimation imposes a significant influence on subsequent tasks such as the camera trajectory dete rmination and 3D reconstruction. In this paper we propose a new method for fundamental matri x estimation that makes use of clustering a group of 4D vectors. The key insight is the obser vation that among the 4D vectors constructed from matching pairs of points obtained from the SIF T algorithm, well-defined cluster points tend to be reliable inliers suitable for fundamenta l matrix estimation. Based on this, we utilizes a recently proposed efficient clustering method thr ough density peaks seeking and propose a new clustering assisted method. Experimental resul ts show that the proposed algorithm is faster and more accurate than currently commonly us ed methods.

  19. Scrambling with matrix black holes

    Science.gov (United States)

    Brady, Lucas; Sahakian, Vatche

    2013-08-01

    If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.

  20. Link Prediction via Matrix Completion

    CERN Document Server

    Pech, Ratha; Pan, Liming; Cheng, Hong; Zhou, Tao

    2016-01-01

    Inspired by practical importance of social networks, economic networks, biological networks and so on, studies on large and complex networks have attracted a surge of attentions in the recent years. Link prediction is a fundamental issue to understand the mechanisms by which new links are added to the networks. We introduce the method of robust principal component analysis (robust PCA) into link prediction, and estimate the missing entries of the adjacency matrix. On one hand, our algorithm is based on the sparsity and low rank property of the matrix, on the other hand, it also performs very well when the network is dense. This is because a relatively dense real network is also sparse in comparison to the complete graph. According to extensive experiments on real networks from disparate fields, when the target network is connected and sufficiently dense, whatever it is weighted or unweighted, our method is demonstrated to be very effective and with prediction accuracy being considerably improved comparing wit...