211At-Rh(16-S4-diol) complex as a precursor for astatine radiopharmaceuticals
211At is one of the most promising radionuclides in α-radioimmunotherapy (α-RIT). Unfortunately, biomolecules labeled by direct electrophilic astatination are unstable due to the rapid loss of 211At under both in vitro and in vivo conditions. The present paper describes the results of our studies on attaching At- to the rhodium(III) complex with thioether ligand: 1,5,9,13-etrathiacyclohexadecane-3,11-diol (16-S4-diol). Rh3+ was chosen as a moderately soft metal cation which should form very strong bonds with soft At- anions, but first of all because of the kinetic inertness of low spin rhodium(III) d6 complexes. The 16-S4-diol ligand was selected due to formation of stable complexes with Rh3+. The experiments related to optimization of the reaction conditions were performed with the 131I, basing on a chemical similarity of I- to At-. The experiments with 211At were then carried out under the conditions found optimal for I-. The preliminary results are promising, and indicate a possibility for astatination of biomolecules by using the 211At-Rh(16-S4-diol) complex
Introduction: The heavy halogen 211At is of great interest for targeted radiotherapy because it decays by the emission of short-range, high-energy α-particles. However, many astatine compounds that have been synthesized are unstable in vivo, providing motivation for seeking other 211At labeling strategies. One relatively unexplored approach is to utilize prosthetic groups based on astatinated rhodium (III) complex stabilized with a tetrathioether macrocyclic ligand – Rh[16aneS4-diol]211At. The purpose of the current study was to evaluate the in vitro and in vivo stability of this complex in comparison to its iodine analog – Rh[16aneS4-diol]131I. Methods: Rh[16aneS4-diol]211At and Rh[16aneS4-diol]131I complexes were synthesized and purified by HPLC. The stability of both complexes was evaluated in vitro by incubation in phosphate-buffered saline (PBS) and human serum at different temperatures. The in vivo behavior of the two radiohalogenated complexes was assessed by a paired-label biodistribution study in normal Balb/c mice. Results: Both complexes were synthesized in high yield and purity. Almost no degradation was observed for Rh[16aneS4-diol]131I in PBS over a 72 h incubation. The astatinated analog exhibited good stability in PBS over 14 h. A slow decline in the percentage of intact complex was observed for both tracers in human serum. In the biodistribution study, retention of 211At in most tissues was higher than that of 131I at all time points, especially in spleen and lungs. Renal clearance of Rh[16aneS4-diol]211At and Rh[16aneS4-diol]131I predominated, with 84.1 ± 2.3% and 94.6 ± 0.9% of injected dose excreted via the urine at 4 h. Conclusions: The Rh[16aneS4-diol]211At complex might be useful for constructing prosthetic groups for the astatination of biomolecules and further studies are planned to evaluate this possibility
The paper surveys the investigations on the chemical behaviour of astatine in organic systems and deals with the preparation and identification of its organic compounds. A discussion is given on some of the physico-chemical properties of these compounds determined by extrapolation techniques as well as by direct measurement. The biomedical importance of 211At-labelled compounds is briefly referred to. (authors)
Methods developed in the Laboratory of Nuclear Problems, JINR, for producing astatine-211 and injecting it into monoclonal antibodies are described. The use of its diethylene triamine penta-acetic acid complex is shown to be the most effective method of injecting astatine into a biomolecules. The biological effect of the α-particles emitted from the astatine-211 is investigated using Chinese hamster fibroblasts and Ehrlich carcinoma cells. It is established that the mitotic activity depression, number of degenerating cells, number of cells with chromosome aberrations, and cellular surviving fraction depend on the concentration of the radionuclide in the medium 'in vitro'. The RBE of α-particles in comparison with 60Co γ-rays is 3. Injection of astatine-211 absorbed on tellurium particles into mice with ascitic tumors resulted in prolongation of their life or elimination of the tumors. (author). 39 refs, 7 figs
Bibliography of astatine chemistry and biomedical applications
An overall bibliography is presented on astatine chemistry and on the biomedical applications of its 211At isotope. The references were grouped in the following chapters: General reviews; Discovery, Natural Occurence; Nuclear Data; Preparation, Handling, Radiation Risk; Physico-chemical Properties; Astatine Compounds and Chemical Reactions; Biological Effects and Applications. Entries are sorted alphabetically by authors name in each chapter, and cross-references to other chapters are provided if appropriate. (R.P.)
Study of Astatine (III) reactions with O, S and N ligands in solution
Full text of publication follows. Astatine (At, Z=85: [Xe]4f145d106s26p5) belongs to the halogen group and is located below iodine in the periodic table. One of its isotopes (211At) appears promising as a therapeutic agent in nuclear medicine (Ref.1) owing to the energy of the alpha particles emitted during the disintegration of its nucleus and its short physical half-life (7.2 h). Since there are no stable isotopes of astatine, the chemistry of this element remains poorly understood. Generally, At is supposed to behave as a halogen (Ref.2) but it has been shown recently in our group that astatine presents a metallic behaviour in aqueous solution: it notably exists as At+ and AtO+ species under the oxidation states +I and +III (Ref.3). At the present time, the number of studies dealing with the complexation properties of the cationic forms of astatine remains limited (Ref.4), owing to its low availability. In this work, we have investigated the reactions of AtO+ species with different hetero-atomic (N, S, O) model ligands. A combined approach based on experimental and theoretical studies has been used (Ref.5). On account of the difficulties of experimental investigations of astatine species, the reactivity of AtO+ was explored using a competition method founded on astatine distributions between two distinct phases. Furthermore, for each AtO+/ ligand complex, the nature of the species formed and the associated thermodynamic constants were determined by computational modeling (DFT calculations). In this framework, an original computational methodology was developed to take into account the specificities of astatine, notably the associated relativistic effects. The computed equilibrium constants have been confronted with the experimental results. This comparison demonstrates an outstanding coherence between experience and theory. Furthermore, the analysis of the results shows a key role of solvent effects on astatine chemistry. Lastly, a specific reactivity for the
Astatine-211: production and availability.
Zalutsky, Michael R; Pruszynski, Marek
2011-07-01
The 7.2-h half life radiohalogen (211)At offers many potential advantages for targeted α-particle therapy; however, its use for this purpose is constrained by its limited availability. Astatine-211 can be produced in reasonable yield from natural bismuth targets via the (209)Bi(α,2n)(211)At nuclear reaction utilizing straightforward methods. There is some debate as to the best incident α-particle energy for maximizing 211At production while minimizing production of (210)At, which is problematic because of its 138.4-day half life α-particle emitting daughter, (210)Po. The intrinsic cost for producing (211)At is reasonably modest and comparable to that of commercially available (123)I. The major impediment to (211)At availability is attributed to the need for a medium energy α-particle beam for its production. On the other hand, there are about 30 cyclotrons in the world that have the beam characteristics required for (211)At production. PMID:22201707
Recent advances in the organic chemistry of astatine
Investigation on the chemical behaviour of astatine in the last decade are surveyed. The survey covers the physical and chemical properties of astatine, synthesis and identification of organic astatine compounds, their physicochemical properties. A special chapter is devoted to biomedical applications, including inorganic 211At species, 211At-labelled proteins and drugs. An extensive bibliography of the related literature is given. (N.T.) 129 refs.; 12 figs.; 14 tabs
Dosimetrical considerations in astatine-211 radioimmunotherapy
Several dosimetrical quantities have been suggested for use in alpha-particle dosimetry. To evaluate the expected biological effect when using these quantities, a Monte Carlo program was set to register the single-event distribution of both specific energy and alpha-particle track length to a cell nucleus (r=5.6 μm). Distributions were acquired for both 'bound' (simulating the effect of 211At-labelled antibodies bound to antigens on cell surfaces (r=7.0 μm)) as well as 'non-bound' (simulating 211At-labelled antibodies that have not bound to a cell) astatine-211. From these distributions, various theoretical cell survival curves were established for 3 different dosimetrical quantities, i.e. specific energy, number of alpha-particle hits and total track length. The survival curves for all quantities are presented for the corresponding mean absorbed dose in order to facilitate comparisons of the expected effects of using the 3 different quantities for both distributions of 211At decays. The theoretical survival curves presented here could, combined with experiments using 'bound' and 'non-bound' 211At in a single-cell suspension, reveal which dosimetrical quantity is most suitable for 211 At-radioimmunotherapy. (author)
Discovery of the astatine, radon, francium, and radium isotopes
Fry, C; Thoennessen, M
2012-01-01
Currently, thirty-nine astatine, thirty-nine radon, thirty-five francium, and thirty-four radium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.
In order to utilize a 211At isotope, a promising α-emitter for radionuclide therapy, the chemical properties of astatine isotopes are studied. We have examined wet chemistry methods through the distribution ratios of astatine in liquid-liquid extraction. The astatine isotopes have been found to be well extracted into DIPE and MIBK. We observed that the distribution ratio of astatine isotopes increases with concentrations of HCl greater than 3 M, while it decreases with the HCl concentration less than 2 M. The results will be useful for development of the 211Rn-211At generator. (author)
Astatine-211-Labeled Targeted Radiotherapeutics: An Update
The heavy halogen 211At was first proposed for use in α-particle targeted radiotherapy more than 30 years ago and continues to be one of the most promising radionuclides for this purpose. Although its 7.2-h half life is not ideal for intravenously administered whole antibodies, it is compatible with the pharmacokinetics of antibody fragments, peptides, aptamers and organic molecules. Its diverse chemistry allows its incorporation into a wide array of targeting vehicles, relying on its chemical similarity to iodine to provide a useful point of departure. On the other hand, the relatively low carbon-astatine bond strength is challenging. In common with the other α-emitters being discussed at this symposium, lack of reliable availability is one of the biggest hurdles in the use of 211At for targeted radiotherapy. However, in the case of 211At, it is not a question of production cost or availability of target material, because 211At can be produced in reasonable yield from natural bismuth targets. Rather, the difficulty is the lack of cyclotrons equipped with the medium energy α-particle beams required for its production. If the infrastructure for producing 211At is to be improved to the stage where 211At-labeled radiopharmaceuticals can have a meaningful impact, several developments must occur. First, the ability to produce clinically relevant levels of 211At that can be shipped to remote locations in chemically tractable form must be demonstrated. Approaches under consideration include compensating for radiolysis-mediated effects and the consideration of alternative chemistries. Second, strategies for compensating for heterogeneities in dose deposition must be developed, hopefully in a way that is compatible with approval for human use. And third, it is essential that more clinical trials be performed with 211At-labeled therapeutics, particularly in settings of minimum residual disease where the radiobiological advantages of α-particles can be best exploited. Our
Scrutinizing "Invisible" astatine: A challenge for modern density functionals.
Sergentu, Dumitru-Claudiu; David, Grégoire; Montavon, Gilles; Maurice, Rémi; Galland, Nicolas
2016-06-01
The main-group 6p elements did not receive much attention in the development of recent density functionals. In many cases it is still difficult to choose among the modern ones a relevant functional for various applications. Here, we illustrate the case of astatine species (At, Z = 85) and we report the first, and quite complete, benchmark study on several properties concerning such species. Insights on geometries, transition energies and thermodynamic properties of a set of 19 astatine species, for which reference experimental or theoretical data has been reported, are obtained with relativistic (two-component) density functional theory calculations. An extensive set of widely used functionals is employed. The hybrid meta-generalized gradient approximation (meta-GGA) PW6B95 functional is overall the best choice. It is worth noting that the range-separated HSE06 functional as well as the old and very popular B3LYP and PBE0 hybrid-GGAs appear to perform quite well too. Moreover, we found that astatine chemistry in solution can accurately be predicted using implicit solvent models, provided that specific parameters are used to build At cavities. © 2016 Wiley Periodicals, Inc. PMID:27059181
Measurement of the first ionization potential of astatine by laser ionization spectroscopy
Rothe, S; Antalic, S; Borschevsky, A; Capponi, L; Cocolios, T E; De Witte, H; Eliav, E; Fedorov, D V; Fedosseev, V N; Fink, D A; Fritzsche, S; Ghys, L; Huyse, M; Imai, N; Kaldor, U; Kudryavtsev, Yu; Köster, U; Lane, J; Lassen, J; Liberati, V; Lynch, K M; Marsh, B A; Nishio, K; Pauwels, D; Pershina, V; Popescu, L; Procter, T J; Radulov, D; Raeder, S; Rajabali, M M; Rapisarda, E; Rossel, R E; Sandhu, K; Seliverstov, M D; Sjödin, A M; Van den Bergh, P; Van Duppen, P; Venhart, M; Wakabayashi, Y; Wendt K D A
2013-01-01
The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of smallest quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ionization potential. Here we use laser spectroscopy to probe the optical spectrum of astatine near the ionization threshold. The observed series of Rydberg states enabled the first determination of the ionization potential of the astatine atom, 9.317510(8) eV. New ab initio calculations were performed to support the experimental result. The measured value serves as a benchmark for quantum chemistry calculations of the properties of astatine as well as for the theoretical prediction of the ionization potential of super-heavy element 117, the heaviest homologue of astatine.
Aneheim, Emma; Gustafsson, Anna; Albertsson, Per; Bäck, Tom; Jensen, Holger; Palm, Stig; Svedhem, Sofia; Lindegren, Sture
2016-03-16
Effective treatment of metastasis is a great challenge in the treatment of different types of cancers. Targeted alpha therapy utilizes the short tissue range (50-100 μm) of α particles, making the method suitable for treatment of disseminated occult cancers in the form of microtumors or even single cancer cells. A promising radioactive nuclide for this type of therapy is astatine-211. Astatine-211 attached to tumor-specific antibodies as carrier molecules is a system currently under investigation for use in targeted alpha therapy. In the common radiolabeling procedure, astatine is coupled to the antibody arbitrarily on lysine residues. By instead coupling astatine to disulfide bridges in the antibody structure, the immunoreactivity of the antibody conjugates could possibly be increased. Here, the disulfide-based conjugation was performed using a new coupling reagent, maleimidoethyl 3-(trimethylstannyl)benzamide (MSB), and evaluated for chemical stability in vitro. The immunoconjugates were subsequently astatinated, resulting in both high radiochemical yield and high specific activity. The MSB-conjugate was shown to be stable with a long shelf life prior to the astatination. In a comparison of the in vivo distribution of the new immunoconjugate with other tin-based immunoconjugates in tumor-bearing mice, the MSB conjugation method was found to be a viable option for successful astatine labeling of different monoclonal antibodies. PMID:26791409
Measurement of the first ionization potential of astatine by laser ionization spectroscopy
Rothe, S.; A. N. Andreyev; Antalic, S; Borschevsky, A.; Capponi, L.; Cocolios, T.E.; Witte, H.; Eliav, E.; Fedorov, D. V.; Fedosseev, V. N.; Fink, D. A.; Fritzsche, S.; Ghys, L.; Huyse, M.; Imai, N.
2013-01-01
The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of the minute quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ionization potential. Here we use laser spectroscopy to probe the optical spectrum of astatine near the io...
Automated astatination of biomolecules - a stepping stone towards multicenter clinical trials
Aneheim, Emma; Albertsson, Per; Bäck, Tom; Jensen, Holger; Palm, Stig; Lindegren, Sture
2015-07-01
To facilitate multicentre clinical studies on targeted alpha therapy, it is necessary to develop an automated, on-site procedure for conjugating rare, short-lived, alpha-emitting radionuclides to biomolecules. Astatine-211 is one of the few alpha-emitting nuclides with appropriate chemical and physical properties for use in targeted therapies for cancer. Due to the very short range of the emitted α-particles, this therapy is particularly suited to treating occult, disseminated cancers. Astatine is not intrinsically tumour-specific; therefore, it requires an appropriate tumour-specific targeting vector, which can guide the radiation to the cancer cells. Consequently, an appropriate method is required for coupling the nuclide to the vector. To increase the availability of astatine-211 radiopharmaceuticals for targeted alpha therapy, their production should be automated. Here, we present a method that combines dry distillation of astatine-211 and a synthesis module for producing radiopharmaceuticals into a process platform. This platform will standardize production of astatinated radiopharmaceuticals, and hence, it will facilitate large clinical studies focused on this promising, but chemically challenging, alpha-emitting radionuclide. In this work, we describe the process platform, and we demonstrate the production of both astaine-211, for preclinical use, and astatine-211 labelled antibodies.
Guérard, François; Lee, Yong-Sok; Baidoo, Kwamena; Gestin, Jean-François; Brechbiel, Martin W
2016-08-22
Aryliodonium salts have become precursors of choice for the synthesis of (18) F-labeled tracers for nuclear imaging. However, little is known on the reactivity of these compounds with heavy halides, that is, radioiodide and astatide, at the radiotracer scale. In the first comparative study of radiohalogenation of aryliodonium salts with (125) I(-) and (211) At(-) , initial experiments on a model compound highlight the higher reactivity of astatide compared to iodide, which could not be anticipated from the trends previously observed within the halogen series. Kinetic studies indicate a significant difference in activation energy (Ea =23.5 and 17.1 kcal mol(-1) with (125) I(-) and (211) At(-) , respectively). Quantum chemical calculations suggest that astatination occurs via the monomeric form of an iodonium complex whereas iodination occurs via a heterodimeric iodonium intermediate. The good to excellent regioselectivity of halogenation and high yields achieved with diversely substituted aryliodonium salts indicate that this class of compounds is a promising alternative to the stannane chemistry currently used for heavy radiohalogen labeling of tracers in nuclear medicine. PMID:27305065
Automated astatination of biomolecules - a stepping stone towards multicenter clinical trials
Aneheim, Emma; Albertsson, Per; Bäck, Tom; Jensen, Holger; Palm, Stig; Lindegren, Sture
2015-01-01
vector, which can guide the radiation to the cancer cells. Consequently, an appropriate method is required for coupling the nuclide to the vector. To increase the availability of astatine-211 radiopharmaceuticals for targeted alpha therapy, their production should be automated. Here, we present a method......To facilitate multicentre clinical studies on targeted alpha therapy, it is necessary to develop an automated, on-site procedure for conjugating rare, short-lived, alpha-emitting radionuclides to biomolecules. Astatine-211 is one of the few alpha-emitting nuclides with appropriate chemical and...... challenging, alpha-emitting radionuclide. In this work, we describe the process platform, and we demonstrate the production of both astaine-211, for preclinical use, and astatine-211 labelled antibodies....
Some aspects of the organic, biological and inorganic chemistry of astatine
Astatine has no stable isotopes and the radioactive isotopes with half-lives sufficiently long for chemical experiments (209At, 210At, 211At) must be produced artificially with a cyclotron or with a high energy accelerator by spallation of Th. This thesis deals with the synthesis and chemistry of At-compounds and the determination of some of their properties. (C.F.)
Astatine-211 Pathway from Radiochemistry to Clinical Investigation
Particularly in clinical settings where tumour burden is low and cancers are located in close proximity to essential normal tissue structures, α-particle emitting radionuclides can offer significant advantages for targeted radionuclide therapy. One of the first alpha emitters to be evaluated for this purpose is the 7.2-h half-life radiohalogen Astatine-211 (211At). From a commercialization-potential perspective 211At, is less appealing than the longer half-life alpha particle emitters Radium-223, Actinium-225 and Thorium-227, which have become the focus of many laboratories. However, if methods for providing a better supply of 211At could be developed, this alpha emitter would be the radionuclide of choice for many potential therapeutic applications. With regard to the production of 211At, this can be readily be accomplished by bombarding natural bismuth targets with 28−29.5 MeV alpha particles via the 209Bi(α,2n)211At reaction. The goal is to utilize an alpha particle beam energy that provides the required balance for maximizing 211At production while minimizing creation of 210At, which is problematic because of its 138.4-day half life alpha-particle emitting daughter, 210Po. For most intended clinical applications, alpha particle beam energy of about 29 MeV offers the best compromise between maximizing yield and providing 211At with sufficient radionuclidic purity for clinical use. Clinically relevant levels of 211At have been produced at several institutions using both internal and external cyclotron targets
An attempt to explore the production routes of Astatine radionuclides: Theoretical approach
Maiti, Moumita; Lahiri, Susanta
2008-01-01
In order to fulfil the recent thrust of Astatine radionuclides in the field of nuclear medicine various production routes have been explored in the present work. The possible production routes of $^{209-211}$At comprise both light and heavy ion induced reactions at the bombarding energy range starting from threshold to maximum 100 MeV energy. For this purpose, we have used the nuclear reaction model codes TALYS, ALICE91 and PACE-II. Excitation functions of those radionuclides, produced throug...
A method for direct astatine labeling of proteins has been investigated. Binding sites for astatine were created by coupling of a nido-carborane derivative to a protein, the human epidermal growth factor (hEGF), using two different conjugation methods - by glutaraldehyde cross-linking or by introduction of sulfohydryl groups by Traut's reagent with subsequent linking of ANC-1 with m-maleimidobenzoyl-N-hydroxysulfosuccinimide ester. The conjugates were astatinated using the Chloramine-T method in high yield. The best labeling was obtained by the glutaraldehyde conjugate with an average yield of 68 ± 9%. In vitro stability tests indicated that the glutaraldehyde conjugated label was as stable as hEGF labeled with astatobenzoate. (author)
Labelling prospects of astatine-211 with immunoglobulins (IgG): some general considerations
The tumour therapeutic potential of the short lived alpha emitting radiohalogen 211At has been already been well recognised in the field of radioimmuno therapy. There is no evidence as such to show that astatine itself is a tumour seeking isotope. Therefore it has to be tagged to tumour seeking compound such as a drug or a protein preferably an antibody (IgG). In this communication, the labelling parameters which are required to be investigated for obtaining a stable product which could be useful as radioimmuno therapeutic agent, are described. (author). 6 refs
Determination of the electron affinity of astatine and polonium by laser photodetachment
We propose to conduct the first electron anity (EA) measurements of the two elements astatine (At) and polonium (Po). Collinear photodetachment spectroscopy will allow us to measure these quantities with an uncertainty limited only by the spectral linewidth of the laser. We plan to use negative ion beams of the two radioactive elements At and Po, which are only accessible on-line and at ISOLDE. The feasibility of our proposed method and the functionality of the experimental setup have been demonstrated at ISOLDE in o-line tests by the clear observation of the photodetachment threshold for stable iodine. This proposal is based on our Letter of Intent I-148 [1].
The extraction behaviour of astatine was studied under defined conditions from hydrochloride acid solutions (cHCl>0.1 M or 1 and 2M). Therefore other effects like adsorption, reduction or hydrolysis can be excluded. The present work describes the extraction with tri- n- octylphosphinoxide (TOPO), tri- n-butylphosphate (TBP) and tri-phenylphosphine in chloroform. (orig.)
The no-carrier-added synthesis of N-succinimidyl 3-[211At]astato-benzoate from N-succinimidyl 3-(tri-n-butylstannyl)benzoate (ATE) is described. The nature of the solvent in which the 211At was isolated from the target was an important factor influencing both the radiochemical yields and the nature of the incorporated astatine activity. (orig.)
Andreyev, Andrei
2013-01-01
Part I: $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with astatine beams; Part II: Delineating the island of deformation in the light gold isotopes by means of laser spectroscopy
ASTATINE-211 RADIOCHEMISTRY: THE DEVELOPMENT OF METHODOLOGIES FOR HIGH ACTIVITY LEVEL RADIOSYNTHESIS
MICHAEL R. ZALUTSKY
2012-08-08
Targeted radionuclide therapy is emerging as a viable approach for cancer treatment because of its potential for delivering curative doses of radiation to malignant cell populations while sparing normal tissues. Alpha particles such as those emitted by 211At are particularly attractive for this purpose because of their short path length in tissue and high energy, making them highly effective in killing cancer cells. The current impact of targeted radiotherapy in the clinical domain remains limited despite the fact that in many cases, potentially useful molecular targets and labeled compounds have already been identified. Unfortunately, putting these concepts into practice has been impeded by limitations in radiochemistry methodologies. A critical problem is that the synthesis of therapeutic radiopharmaceuticals provides additional challenges in comparison to diagnostic reagents because of the need to perform radio-synthesis at high levels of radioactivity. This is particularly important for {alpha}-particle emitters such as 211At because they deposit large amounts of energy in a highly focal manner. The overall objective of this project is to develop convenient and reproducible radiochemical methodologies for the radiohalogenation of molecules with the {alpha}-particle emitter 211At at the radioactivity levels needed for clinical studies. Our goal is to address two problems in astatine radiochemistry: First, a well known characteristic of 211At chemistry is that yields for electrophilic astatination reactions decline as the time interval after radionuclide isolation from the cyclotron target increases. This is a critical problem that must be addressed if cyclotrons are to be able to efficiently supply 211At to remote users. And second, when the preparation of high levels of 211At-labeled compounds is attempted, the radiochemical yields can be considerably lower than those encountered at tracer dose. For these reasons, clinical evaluation of promising 211At
Rothe, Sebastian; Nörtershäuser, W
This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at ISOLDE, CERN, by the addition of an all-solid state tuneable titanium: sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE, CERN, and at ISAC, TRIUMF, radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.
Rothe, Sebastian
2012-09-24
This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at CERN/ISOLDE by the addition of an all-solid state tunable titanium:sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE/CERN and at ISAC/TRIUMF radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.
This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at CERN/ISOLDE by the addition of an all-solid state tunable titanium:sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE/CERN and at ISAC/TRIUMF radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.
Gershenson, Carlos
2011-01-01
The term complexity derives etymologically from the Latin plexus, which means interwoven. Intuitively, this implies that something complex is composed by elements that are difficult to separate. This difficulty arises from the relevant interactions that take place between components. This lack of separability is at odds with the classical scientific method - which has been used since the times of Galileo, Newton, Descartes, and Laplace - and has also influenced philosophy and engineering. In recent decades, the scientific study of complexity and complex systems has proposed a paradigm shift in science and philosophy, proposing novel methods that take into account relevant interactions.
Wilbur, D., Scott
2011-12-14
The overall objective of this research effort was to develop methods for labeling biomolecules with higher oxidation state species of At-211. This was to be done in an effort to develop reagents that had higher in vivo stability than the present carbon-bonded At-211-labeled compounds. We were unsuccessful in that effort, as none of the approaches studied provided reagents that were stable to in vivo deastatination. However, we gained a lot of information about At-211 in higher oxidation states. The studies proved to be very difficult as small changes in pH and other conditions appeared to change the nature of the species that obtained (by HPLC retention time analyses), with many of the species being unidentifiable. The fact that there are no stable isotopes of astatine, and the chemistry of the nearest halogen iodine is quite different, made it very difficult to interpret results of some experiments. With that said, we believe that a lot of valuable information was obtained from the studies. The research effort evaluated: (1) methods for chemical oxidation of At-211, (2) approaches to chelation of oxidized At-211, and (3) approaches to oxidation of astatophenyl compounds. A major hurdle that had to be surmounted to conduct the research was the development of HPLC conditions to separate and identify the various oxidized species formed. Attempts to develop conditions for separation of iodine and astatine species by normal and reversed-phase TLC and ITLC were not successful. However, we were successful in developing conditions (from a large number of attempts) to separate oxidized forms of iodine ([I-125]iodide, [I-125]iodate and [I-125]periodate) and astatine ([At-211]astatide, [At-211]astatate, [At-211]perastatate, and several unidentified At-211 species). Information on the basic oxidation and characterization of At-211 species is provided under Objective 1. Conditions were developed to obtain new At-211 labeling method where At-211 is chelated with the DOTA and
The sodium/iodide symporter (NIS) has been recognized as an attractive target for radioiodine-mediated cancer gene therapy. In this study we investigated the role of human NIS for cellular uptake of the high LET α-emitter astatine-211 (211At) in comparison with radioiodine as a potential radionuclide for future applications. A mammalian NIS expression vector was constructed and used to generate six stable NIS-expressing cancer cell lines (three derived from thyroid carcinoma, two from colon carcinoma, one from glioblastoma). Compared with the respective control cell lines, steady state radionuclide uptake of NIS-expressing cell lines increased up to 350-fold for iodine-123 (123I), 340-fold for technetium-99m pertechnetate (99mTcO4-) and 60-fold for 211At. Cellular 211At accumulation was found to be dependent on extracellular Na+ ions and displayed a similar sensitivity towards sodium perchlorate inhibition as radioiodide and 99mTcO4- uptake. Heterologous competition with unlabelled NaI decreased NIS-mediated 211At uptake to levels of NIS-negative control cells. Following uptake both radioiodide and 211At were rapidly (apparent t1/2 3-15 min) released by the cells as determined by wash-out experiments. Data of scintigraphic tumour imaging in a xenograft nude mice model of transplanted NIS-modified thyroid cells indicated that radionuclide uptake in NIS-expressing tumours was up to 70 times (123I), 25 times (99mTcO4-) and 10 times (211At) higher than in control tumours or normal tissues except stomach (3-5 times) and thyroid gland (5-10 times). Thirty-four percent and 14% of the administered activity of 123I and 211At, respectively, was found in NIS tumours by region of interest analysis (n=2). Compared with cell culture experiments, the effective half-life in vivo was greatly prolonged (6.5 h for 123I, 5.2 h for 211At) and preliminary dosimetric calculations indicate high tumour absorbed doses (3.5 Gy/MBqtumour for 131I and 50.3 Gy/MBqtumour for 211At). In
Petrich, T.; Helmeke, H.-J.; Meyer, G.J.; Knapp, W.H.; Poetter, E. [Department of Nuclear Medicine, Medizinische Hochschule Hannover (Germany)
2002-07-01
The sodium/iodide symporter (NIS) has been recognized as an attractive target for radioiodine-mediated cancer gene therapy. In this study we investigated the role of human NIS for cellular uptake of the high LET {alpha}-emitter astatine-211 ({sup 211}At) in comparison with radioiodine as a potential radionuclide for future applications. A mammalian NIS expression vector was constructed and used to generate six stable NIS-expressing cancer cell lines (three derived from thyroid carcinoma, two from colon carcinoma, one from glioblastoma). Compared with the respective control cell lines, steady state radionuclide uptake of NIS-expressing cell lines increased up to 350-fold for iodine-123 ({sup 123}I), 340-fold for technetium-99m pertechnetate ({sup 99m}TcO{sub 4}{sup -}) and 60-fold for {sup 211}At. Cellular {sup 211}At accumulation was found to be dependent on extracellular Na{sup +} ions and displayed a similar sensitivity towards sodium perchlorate inhibition as radioiodide and {sup 99m}TcO{sub 4}{sup -} uptake. Heterologous competition with unlabelled NaI decreased NIS-mediated {sup 211}At uptake to levels of NIS-negative control cells. Following uptake both radioiodide and {sup 211}At were rapidly (apparent t{sub 1/2} 3-15 min) released by the cells as determined by wash-out experiments. Data of scintigraphic tumour imaging in a xenograft nude mice model of transplanted NIS-modified thyroid cells indicated that radionuclide uptake in NIS-expressing tumours was up to 70 times ({sup 123}I), 25 times ({sup 99m}TcO{sub 4}{sup -}) and 10 times ({sup 211}At) higher than in control tumours or normal tissues except stomach (3-5 times) and thyroid gland (5-10 times). Thirty-four percent and 14% of the administered activity of {sup 123}I and {sup 211}At, respectively, was found in NIS tumours by region of interest analysis (n=2). Compared with cell culture experiments, the effective half-life in vivo was greatly prolonged (6.5 h for {sup 123}I, 5.2 h for {sup 211}At) and
Chen, Yun; Kornblit, Brian; Hamlin, Donald K; Sale, George E; Santos, Erlinda B; Wilbur, D Scott; Storer, Barry E; Storb, Rainer; Sandmaier, Brenda M
2012-02-01
To reduce toxicity associated with external γ-beam radiation, we investigated radioimmunotherapy with an anti-CD45 mAb labeled with the α-emitter, astatine-211 ((211)At), as a conditioning regimen in dog leukocyte antigen-identical hematopoietic cell transplantation (HCT). Dose-finding studies in 6 dogs treated with 100 to 618 μCi/kg (211)At-labeled anti-CD45 mAb (0.5 mg/kg) without HCT rescue demonstrated dose-dependent myelosuppression with subsequent autologous recovery, and transient liver toxicity in dogs treated with (211)At doses less than or equal to 405 μCi/kg. Higher doses of (211)At induced clinical liver failure. Subsequently, 8 dogs were conditioned with 155 to 625 μCi/kg (211)At-labeled anti-CD45 mAb (0.5 mg/kg) before HCT with dog leukocyte antigen-identical bone marrow followed by a short course of cyclosporine and mycophenolate mofetil immunosuppression. Neutropenia (1-146 cells/μL), lymphopenia (0-270 cells/μL), and thrombocytopenia (1500-6560 platelets/μL) with prompt recovery was observed. Seven dogs had long-term donor mononuclear cell chimerism (19%-58%), whereas 1 dog treated with the lowest (211)At dose (155 μCi/kg) had low donor mononuclear cell chimerism (5%). At the end of follow-up (18-53 weeks), only transient liver toxicity and no renal toxicity had been observed. In conclusion, conditioning with (211)At-labeled anti-CD45 mAb is safe and efficacious and provides a platform for future clinical trials of nonmyeloablative transplantation with radioimmunotherapy-based conditioning. PMID:22134165
The EGFR-TKI (epidermal growth factor receptor tyrosine kinase inhibitor) gefitinib (''Iressa'', ZD1839), a reversible growth inhibitor of EGFR-expressing tumour cells, has been shown to enhance the antitumour effect of ionising radiation, and also to increase the uptake of radioiodinated EGF. Thus, combination of gefitinib treatment and radionuclide targeting is an interesting option for therapy of brain tumours that are difficult to treat with conventional methods. The aim of this study was to evaluate how pre-treatment with gefitinib affects binding of astatinated EGF (211At-EGF) to cultured glioma U343 cells, which express high levels of EGFR. The growth of U343 cells in the presence of gefitinib was investigated, and it was found that gefitinib does not significantly inhibit the growth of these cells. Nevertheless, the uptake of 211At-EGF in U343 cells was markedly increased (up to 3.5 times) in cells pre-treated with gefitinib (1 μM). This indicates that a combination of gefitinib treatment and radionuclide targeting to EGFR might be a useful therapeutic modality, even for patients who do not respond to treatment with gefitinib alone. (orig.)
Astatination of closo-dodecaborate(2-) anion
Orlova, A.; Lebeda, Ondřej; Tolmachev, V.; Lundquist, H.; Carlsson, J.; Sjöberg, S.
Cambridge : The Royal Society of Chemistry , 2000 - (Davidson, M.; Hughes, A.; Marder, T.; Wade , K.), s. 144-147 [Conference "Contemporary Boron Chemistry ". Durham (GB), 11.07.1999-15.07.1999] Institutional research plan: CEZ:AV0Z1048901 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Franceschet, Massimo
2014-01-01
Complex systems and their underlying convoluted networks are ubiquitous, all we need is an eye for them. They pose problems of organized complexity which cannot be approached with a reductionist method. Complexity science and its emergent sister network science both come to grips with the inherent complexity of complex systems with an holistic strategy. The relevance of complexity, however, transcends the sciences. Complex systems and networks are the focal point of a philosophical, cultural ...
Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon
2006-06-15
This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.
This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.
Brešar, Bostjan; Chepoi, Victor; Gologranc, Tanja; Osajda, Damian
2012-01-01
In this article, we introduce and investigate bucolic complexes, a common generalization of systolic complexes and of CAT(0) cubical complexes. This class of complexes is closed under Cartesian products and amalgamations over some convex subcomplexes. We study various approaches to bucolic complexes: from graph-theoretic and topological viewpoints, as well as from the point of view of geometric group theory. Bucolic complexes can be defined as locally-finite simply connected prism complexes satisfying some local combinatorial conditions. We show that bucolic complexes are contractible, and satisfy some nonpositive-curvature-like properties. In particular, we prove a version of the Cartan-Hadamard theorem, the fixed point theorem for finite group actions, and establish some results on groups acting geometrically on such complexes. We also characterize the 1-skeletons (which we call bucolic graphs) and the 2-skeletons of bucolic complexes. In particular, we prove that bucolic graphs are precisely retracts of Ca...
Cartwright, Dustin
2013-01-01
We introduce tropical complexes, which are Delta-complexes together with additional numerical data. On a tropical complex, we define divisors and linear equivalence between divisors, analogous to the notions for algebraic varieties, and generalizing previous work for graphs. We prove a comparison theorem showing that divisor-curve intersection numbers agree under certain conditions.
Kumaraswamy, Mohan
2002-01-01
One element of the CIVCAL project Web-based resources containing images, tables, texts and associated data on the construction of the Medical Complex. This project covers the construction of a new Hong Kong University Medical Complex on Sassoon Road, Pokfulam. The complex will comprise two buildings, one will house laboratories and a car park, while the other will contain lecture halls
Communication complexity and information complexity
Pankratov, Denis
Information complexity enables the use of information-theoretic tools in communication complexity theory. Prior to the results presented in this thesis, information complexity was mainly used for proving lower bounds and direct-sum theorems in the setting of communication complexity. We present three results that demonstrate new connections between information complexity and communication complexity. In the first contribution we thoroughly study the information complexity of the smallest nontrivial two-party function: the AND function. While computing the communication complexity of AND is trivial, computing its exact information complexity presents a major technical challenge. In overcoming this challenge, we reveal that information complexity gives rise to rich geometrical structures. Our analysis of information complexity relies on new analytic techniques and new characterizations of communication protocols. We also uncover a connection of information complexity to the theory of elliptic partial differential equations. Once we compute the exact information complexity of AND, we can compute exact communication complexity of several related functions on n-bit inputs with some additional technical work. Previous combinatorial and algebraic techniques could only prove bounds of the form theta( n). Interestingly, this level of precision is typical in the area of information theory, so our result demonstrates that this meta-property of precise bounds carries over to information complexity and in certain cases even to communication complexity. Our result does not only strengthen the lower bound on communication complexity of disjointness by making it more exact, but it also shows that information complexity provides the exact upper bound on communication complexity. In fact, this result is more general and applies to a whole class of communication problems. In the second contribution, we use self-reduction methods to prove strong lower bounds on the information
Thiyagalingam, Jeyarajan
2013-06-01
In this paper, we present a novel visualization technique for assisting the observation and analysis of algorithmic complexity. In comparison with conventional line graphs, this new technique is not sensitive to the units of measurement, allowing multivariate data series of different physical qualities (e.g., time, space and energy) to be juxtaposed together conveniently and consistently. It supports multivariate visualization as well as uncertainty visualization. It enables users to focus on algorithm categorization by complexity classes, while reducing visual impact caused by constants and algorithmic components that are insignificant to complexity analysis. It provides an effective means for observing the algorithmic complexity of programs with a mixture of algorithms and black-box software through visualization. Through two case studies, we demonstrate the effectiveness of complexity plots in complexity analysis in research, education and application. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and Blackwell Publishing Ltd.
Gys M. Loubser
2014-01-01
Full Text Available In this article, I discuss studies in complexity and its epistemological implications for systematic and practical theology. I argue that engagement with complexity does not necessarily assurea non-reductionist approach. However, if complexity is engaged transversally, it becomes possible to transcend reductionist approaches. Moreover, systematic and practical the ologians can draw on complexity in developing new ways of understanding and, therefore, new ways of describing the focus, epistemic scope and heuristic structures of systematic and practical theology. Firstly, Edgar Morin draws a distinction between restricted and general complexity based on the epistemology drawn upon in studies in complexity. Moving away from foundationalist approaches to epistemology, Morin argues for a paradigm of systems. Secondly,I discuss Kees van Kooten Niekerk�s distinction between epistemology, methodology andontology in studies in complexity and offer an example of a theological argument that drawson complexity. Thirdly, I argue for the importance of transversality in engaging complexity by drawing on the work of Wentzel van Huyssteen and Paul Cilliers. In conclusion, I argue that theologians have to be conscious of the epistemic foundations of each study in complexity, and these studies illuminate the heart of Reformed theology.Intradisciplinary and/or interdisciplinary implications: Therefore, this article has both intradisciplinary and interdisciplinary implications. When theologians engage studies incomplexity, the epistemological roots of these studies need to be considered seeing thatresearchers in complexity draw on different epistemologies. Drawing on transversality wouldenhance such considerations. Furthermore, Edgar Morin�s and Paul Cilliers� approach tocomplexity will inform practical and theoretical considerations in church polity and unity.
... of Carney complex are Cushing’s syndrome and multiple thyroid nodules (tumors). Cushing’s syndrome features a combination of weight gain, ... with Carney complex include adrenocortical carcinoma , pituitary gland tumors , thyroid , colorectal , liver and pancreatic cancers . Ovarian cancer in ...
Leemput, van de I.A.
2016-01-01
In this thesis I use mathematical models to explore the properties of complex systems ranging from microbial nitrogen pathways and coral reefs to the human state of mind. All are examples of complex systems, defined as systems composed of a number of interconnected parts, where the systemic behavior
In recent years we have seen the birth of a new field known as Hamiltonian complexity lying at the crossroads between computer science and theoretical physics. Hamiltonian complexity is directly concerned with the question: how hard is it to simulate a physical system? Here I review the foundational results, guiding problems, and future directions of this emergent field.
Maylath, Bruce; Vandepitte, Sonia; Minacori, Patricia;
2013-01-01
and into French. The complexity of the undertaking proved to be a central element in the students' learning, as the collaboration closely resembles the complexity of international documentation workplaces of language service providers. © Association of Teachers of Technical Writing.......This article discusses the largest and most complex international learning-by-doing project to date- a project involving translation from Danish and Dutch into English and editing into American English alongside a project involving writing, usability testing, and translation from English into Dutch...
Fisher, Stephen D
1999-01-01
The most important topics in the theory and application of complex variables receive a thorough, coherent treatment in this introductory text. Intended for undergraduates or graduate students in science, mathematics, and engineering, this volume features hundreds of solved examples, exercises, and applications designed to foster a complete understanding of complex variables as well as an appreciation of their mathematical beauty and elegance. Prerequisites are minimal; a three-semester course in calculus will suffice to prepare students for discussions of these topics: the complex plane, basic
Frieder Kleefeld
2013-01-01
Full Text Available According to some generalized correspondence principle the classical limit of a non-Hermitian quantum theory describing quantum degrees of freedom is expected to be the well known classical mechanics of classical degrees of freedom in the complex phase space, i.e., some phase space spanned by complex-valued space and momentum coordinates. As special relativity was developed by Einstein merely for real-valued space-time and four-momentum, we will try to understand how special relativity and covariance can be extended to complex-valued space-time and four-momentum. Our considerations will lead us not only to some unconventional derivation of Lorentz transformations for complex-valued velocities, but also to the non-Hermitian Klein-Gordon and Dirac equations, which are to lay the foundations of a non-Hermitian quantum theory.
Leemput, van de, J.C.H.
2016-01-01
In this thesis I use mathematical models to explore the properties of complex systems ranging from microbial nitrogen pathways and coral reefs to the human state of mind. All are examples of complex systems, defined as systems composed of a number of interconnected parts, where the systemic behavior leads to the emergence of properties that would not be expected from behavior or properties of the individual parts of the system. Although the full behavior of the systems I address will probably...
Complex networks: Patterns of complexity
Pastor-Satorras, Romualdo; Vespignani, Alessandro
2010-07-01
The Turing mechanism provides a paradigm for the spontaneous generation of patterns in reaction-diffusion systems. A framework that describes Turing-pattern formation in the context of complex networks should provide a new basis for studying the phenomenon.
Freitag, Eberhard
2005-01-01
The guiding principle of this presentation of ``Classical Complex Analysis'' is to proceed as quickly as possible to the central results while using a small number of notions and concepts from other fields. Thus the prerequisites for understanding this book are minimal; only elementary facts of calculus and algebra are required. The first four chapters cover the essential core of complex analysis: - differentiation in C (including elementary facts about conformal mappings) - integration in C (including complex line integrals, Cauchy's Integral Theorem, and the Integral Formulas) - sequences and series of analytic functions, (isolated) singularities, Laurent series, calculus of residues - construction of analytic functions: the gamma function, Weierstrass' Factorization Theorem, Mittag-Leffler Partial Fraction Decomposition, and -as a particular highlight- the Riemann Mapping Theorem, which characterizes the simply connected domains in C. Further topics included are: - the theory of elliptic functions based on...
Evsukoff, Alexandre; González, Marta
2013-01-01
In the last decade we have seen the emergence of a new inter-disciplinary field focusing on the understanding of networks which are dynamic, large, open, and have a structure sometimes called random-biased. The field of Complex Networks is helping us better understand many complex phenomena such as the spread of deseases, protein interactions, social relationships, to name but a few. Studies in Complex Networks are gaining attention due to some major scientific breakthroughs proposed by network scientists helping us understand and model interactions contained in large datasets. In fact, if we could point to one event leading to the widespread use of complex network analysis is the availability of online databases. Theories of Random Graphs from Erdös and Rényi from the late 1950s led us to believe that most networks had random characteristics. The work on large online datasets told us otherwise. Starting with the work of Barabási and Albert as well as Watts and Strogatz in the late 1990s, we now know th...
Chassin, David P.; Posse, Christian; Malard, Joel M.
2004-08-01
Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today’s most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically-based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This paper explores the state of the art in the use physical analogs for understanding the behavior of some econophysical systems and to deriving stable and robust control strategies for them. In particular we review and discussion applications of some analytic methods based on the thermodynamic metaphor according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood.
Carleson, Lennart
1993-01-01
Complex dynamics is today very much a focus of interest. Though several fine expository articles were available, by P. Blanchard and by M. Yu. Lyubich in particular, until recently there was no single source where students could find the material with proofs. For anyone in our position, gathering and organizing the material required a great deal of work going through preprints and papers and in some cases even finding a proof. We hope that the results of our efforts will be of help to others who plan to learn about complex dynamics and perhaps even lecture. Meanwhile books in the field a. re beginning to appear. The Stony Brook course notes of J. Milnor were particularly welcome and useful. Still we hope that our special emphasis on the analytic side will satisfy a need. This book is a revised and expanded version of notes based on lectures of the first author at UCLA over several \\Vinter Quarters, particularly 1986 and 1990. We owe Chris Bishop a great deal of gratitude for supervising the production of cour...
Yi Zhao
2012-01-01
Full Text Available Quantum instanton (QI approximation is recently proposed for the evaluations of the chemical reaction rate constants with use of full dimensional potential energy surfaces. Its strategy is to use the instanton mechanism and to approximate time-dependent quantum dynamics to the imaginary time propagation of the quantities of partition function. It thus incorporates the properties of the instanton idea and the quantum effect of partition function and can be applied to chemical reactions of complex systems. In this paper, we present the QI approach and its applications to several complex systems mainly done by us. The concrete systems include, (1 the reaction of H+CH4→H2+CH3, (2 the reaction of H+SiH4→H2+SiH3, (3 H diffusion on Ni(100 surface; and (4 surface-subsurface transport and interior migration for H/Ni. Available experimental and other theoretical data are also presented for the purpose of comparison.
Mather, John C.
2012-01-01
What explains the extraordinary complexity of the observed universe, on all scales from quarks to the accelerating universe? My favorite explanation (which I certainty did not invent) ls that the fundamental laws of physics produce natural instability, energy flows, and chaos. Some call the result the Life Force, some note that the Earth is a living system itself (Gaia, a "tough bitch" according to Margulis), and some conclude that the observed complexity requires a supernatural explanation (of which we have many). But my dad was a statistician (of dairy cows) and he told me about cells and genes and evolution and chance when I was very small. So a scientist must look for me explanation of how nature's laws and statistics brought us into conscious existence. And how is that seemll"!gly Improbable events are actually happening a!1 the time? Well, the physicists have countless examples of natural instability, in which energy is released to power change from simplicity to complexity. One of the most common to see is that cooling water vapor below the freezing point produces snowflakes, no two alike, and all complex and beautiful. We see it often so we are not amazed. But physlc!sts have observed so many kinds of these changes from one structure to another (we call them phase transitions) that the Nobel Prize in 1992 could be awarded for understanding the mathematics of their common features. Now for a few examples of how the laws of nature produce the instabilities that lead to our own existence. First, the Big Bang (what an insufficient name!) apparently came from an instability, in which the "false vacuum" eventually decayed into the ordinary vacuum we have today, plus the most fundamental particles we know, the quarks and leptons. So the universe as a whole started with an instability. Then, a great expansion and cooling happened, and the loose quarks, finding themselves unstable too, bound themselves together into today's less elementary particles like protons and
S. Pietrowski
2007-09-01
Full Text Available Purpose: The study presents the results of investigations carried out on silumins with additions of Mg, Ni, Cu, Cr, Mo and W. The silumins containing Mg, Cu and Ni are well-known and commonly used in construction of machines and equipment.Design/methodology/approach: Additions of Cr, Mo and W have not been thoroughly investigated yet. They are considered a new family of innovative cast aluminium alloys.Findings: In Al-Si systems they form silicides, like Cr3Si, Mo3Si, W3Si and intermetallic phases of Al13Cr4Si4, Al12Mo, Al12W and AlWSi. The silicides crystallise in cubic lattice of parameters similar to aluminium and silicon.Research limitations/implications: Therefore they can act as crystallisation substrates and occur as separate phases. The examinations under the microscope and X-ray microanalysis of the linear and point distribution of elements confirmed the presence of the above mentioned phases. A combination of two elements, e.g. Cr and Mo, or Cr and W, was observed to cause the formation of complex silicide layers of Mo3Si and (Cr, Mo3Si, or Cr3Si as well as (W, Cr3Si.Originality/value: The presence of the silicides has been indicated as a possible source of the refinement of α(Al and β(Si phases. The precipitations of these phases and of the intermetallic phases favour a high degree of the silumins hardening. A characteristic feature is the fact that nucleation and crystallisation of the successive phases takes place at the phase boundaries formed between the previously precipitated phase and solid solution α. The studies carried out so far have indicated that in complex silumins at high temperatures crystallise the silicides and peritectic phases of Al12W, AlWSi, Al12Mo and Al13Cr4Si4. Phases α or β are the next ones to crystallise, followed by complex eutectic α + β +Al(Si, Cr, Mo, W, Fe. Further crystallise the phases of Mg2Si, Al3Ni and Al2Cu. The silumins presented here are characterised by high mechanical properties: Rp0
Process for producing astatine-211 for radiopharmaceutical use
A one-step chemical manipulation is described in combination with a distillation and collection process for producing At-211 comprising; a. providing a target of irradiated Bismuth coated to a predetermined thickness of a backing member, b. providing a vapor-producing still operably connected with a condenser that has a water cooled condensate collector formed of a dry silica gel mesh maintained at a temperature above the freezing point of water, and providing an effluent gas filter that is operably connected to receive effluent gas from the condenser, c. heating the target in the still at a temperature in the range of about 6300-6800C for a time period in the range of 50 to 80 minutes, to evole At-211 vapor from the target, c. providing a dry carrier gas having an oxygen concentration that is sufficient to form Bi/sub 2/O/sub 3/ thereby to essentially preclude vaporization of Bi metal, passing the carrier gas through the still to carry the At-211 vapor to the condenser, and to carry effluent from the condenser to the effluent gas filter, e. eluting At-211 from the condensate collector of the condenser with a controlled volume of eluent containing predetermined solvents that are compatible with a given desired radiopharmaceutical procedure, and f. collecting the At-211 in the controlled volume of eluent for use in the given radiopharmaceutical procedure
Aneheim, Emma; Halleröd, Jenny; Albertsson, Per; Jensen, Holger; Holgersson, Stellan; Lindegren, Sture
2015-01-01
Astatine-211 is possibly the most promising radionuclide for targeted α-particle therapy when it comes to the treatment of occult disseminated cancer. Preclinical research has proven effective, and patient studies have been initiated based on these results. However, a lack of production capacity and the complex radiochemistry of 211At are major obstacles for research and prospective clinical applications. In the present study, astatination of immunoconjugates, already prepared well in advance...
David Ulph
2014-01-01
This paper critically examines a number of issues relating to the measurement of tax complexity. It starts with an analysis of the concept of tax complexity, distinguishing tax design complexity and operational complexity. It considers the consequences/costs of complexity, and then examines the rationale for measuring complexity. Finally it applies the analysis to an examination of an index of complexity developed by the UK Office of Tax Simplification (OTS). Postprint
On State Complexes and Special Cube Complexes
Peterson, Valerie J.
2009-01-01
This thesis presents the first steps toward a classification of non-positively curved cube complexes called state complexes. A "state complex" is a configuration space for a "reconfigurable system," i.e., an abstract system in which local movements occur in some discrete manner. Reconfigurable systems can be used to describe, for example,…
Malihe Alikhani; Bj{\\o}rn Kjos-Hanssen; Amirarsalan Pakravan; Babak Saadat
2015-01-01
We consider options that pay the complexity deficiency of a sequence of up and down ticks of a stock upon exercise. We study the price of European and American versions of this option numerically for automatic complexity, and theoretically for Kolmogorov complexity. We also consider run complexity, which is a restricted form of automatic complexity.
Second Quantized Kolmogorov Complexity
Rogers, Caroline; Vedral, Vlatko; Nagarajan, Rajagopal
2008-01-01
The Kolmogorov complexity of a string is the length of its shortest description. We define a second quantised Kolmogorov complexity where the length of a description is defined to be the average length of its superposition. We discuss this complexity's basic properties. We define the corresponding prefix complexity and show that the inequalities obeyed by this prefix complexity are also obeyed by von Neumann entropy.
Complex Multiplicative Calculus
Bashirov, Agamirza; Riza, Mustafa
2011-01-01
In the present paper we extend the concepts of multiplicative de- rivative and integral to complex-valued functions of complex variable. Some drawbacks, arising with these concepts in the real case, are explained satis- factorily. Properties of complex multiplicative derivatives and integrals are studied. In particular, the fundamental theorem of complex multiplicative calculus, relating these concepts, is proved. It is shown that complex multi- plicative calculus is not just another realizat...
Complex networks analysis of language complexity
Amancio, Diego R; Oliveira, Osvaldo N; Costa, Luciano da F; 10.1209/0295-5075/100/58002
2013-01-01
Methods from statistical physics, such as those involving complex networks, have been increasingly used in quantitative analysis of linguistic phenomena. In this paper, we represented pieces of text with different levels of simplification in co-occurrence networks and found that topological regularity correlated negatively with textual complexity. Furthermore, in less complex texts the distance between concepts, represented as nodes, tended to decrease. The complex networks metrics were treated with multivariate pattern recognition techniques, which allowed us to distinguish between original texts and their simplified versions. For each original text, two simplified versions were generated manually with increasing number of simplification operations. As expected, distinction was easier for the strongly simplified versions, where the most relevant metrics were node strength, shortest paths and diversity. Also, the discrimination of complex texts was improved with higher hierarchical network metrics, thus point...
Vincristine Lipid Complex Injection
Vincristine lipid complex is used to treat a certain type of acute lymphoblastic leukemia (ALL; a type ... at least two different treatments with other medications. Vincristine lipid complex is in a class of medications ...
Rafi, Kasra; Schleimer, Saul
2007-01-01
Any quasi-isometry of the complex of curves is bounded distance from a simplicial automorphism. As a consequence, the quasi-isometry type of the curve complex determines the homeomorphism type of the surface.
Parwani, R R
2002-01-01
This article summarises a Web-book on "Complexity" that was developed to introduce undergraduate students to interesting complex systems in the biological, physical and social sciences, and the common tools, principles and concepts used for their study.
Oligocyclopentadienyl transition metal complexes
de Azevedo, Cristina G.; Vollhardt, K. Peter C.
2002-01-18
Synthesis, characterization, and reactivity studies of oligocyclopentadienyl transition metal complexes, namely those of fulvalene, tercyclopentadienyl, quatercyclopentadienyl, and pentacyclopentadienyl(cyclopentadienyl) are the subject of this account. Thermal-, photo-, and redox chemistries of homo- and heteropolynuclear complexes are described.
Quantum Communication Complexity
Klauck, Hartmut
2000-01-01
This paper surveys the field of quantum communication complexity. Some interesting recent results are collected concerning relations to classical communication, lower bound methods, one-way communication, and applications of quantum communication complexity.
Irinotecan Lipid Complex Injection
Irinotecan lipid complex is used in combination with other medications to treat pancreatic cancer that has spread to other parts of ... after treatment with other chemotherapy medications. Irinotecan lipid complex is in a class of antineoplastic medications called ...
Vincristine Lipid Complex Injection
Vincristine lipid complex is used to treat a certain type of acute lymphoblastic leukemia (ALL; a type of cancer of the ... two different treatments with other medications. Vincristine lipid complex is in a class of medications called vinca ...
Doxorubicin Lipid Complex Injection
Doxorubicin lipid complex is used to treat ovarian cancer that has not improved or that has worsened after treatment with other medications. Doxorubicin lipid complex is also used to treat Kaposi's sarcoma (a ...
Mycobacterium Avium Complex (MAC)
... Select a Language: Fact Sheet 514 Mycobacterium Avium Complex (MAC) WHAT IS MAC? HOW DO I KNOW ... THE BOTTOM LINE WHAT IS MAC? Mycobacterium Avium Complex (MAC) is a serious illness caused by common ...
Cytarabine Lipid Complex Injection
Cytarabine lipid complex is used to treat lymphomatous meningitis (a type of cancer in the covering of the spinal cord and brain). Cytarabine lipid complex is in a class of medications called antimetabolites. ...
Evolution of biological complexity
Adami, Christoph; Ofria, Charles; Collier, Travis C.
2000-01-01
In order to make a case for or against a trend in the evolution of complexity in biological evolution, complexity needs to be both rigorously defined and measurable. A recent information-theoretic (but intuitively evident) definition identifies genomic complexity with the amount of information a sequence stores about its environment. We investigate the evolution of genomic complexity in populations of digital organisms and monitor in detail the evolutionary transitions that increase complexit...
Halyo, Edi
2015-01-01
We generalize the concept of complexity near horizons to all nondegenerate black holes. For Schwarzschild black holes, we show that Rindler observers see a complexity change of $S$ during proper time $1/\\kappa$ which corresponds to the creation of a causal patch with proper length $1/\\kappa$ inside the horizon. We attempt to describe complexity in the horizon CFT and the Euclidean picture.
Complex variables I essentials
Solomon, Alan D
2013-01-01
REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Complex Variables I includes functions of a complex variable, elementary complex functions, integrals of complex functions in the complex plane, sequences and series, and poles and r
WANG Chenghong; ZHANG Lijun
2004-01-01
Science of Complexity is a newly emerging branch of natural scienceAlthoughwe still haven't a precise definition, there are some principles for justifying whether a systemis a complex systemThe purpose of this article is to reveal some of such principlesOnthe basis of them, the concept of a system with complexity is proposedThey may helpus to distinguish a real complex system from complicated objects in common senseThenwe propose some fundamental problems faced by the study of systems with complexity.
Randomness, Information, and Complexity
Grassberger, Peter
2012-01-01
We review possible measures of complexity which might in particular be applicable to situations where the complexity seems to arise spontaneously. We point out that not all of them correspond to the intuitive (or "naive") notion, and that one should not expect a unique observable of complexity. One of the main problems is to distinguish complex from disordered systems. This and the fact that complexity is closely related to information requires that we also give a review of information measures. We finally concentrate on quantities which measure in some way or other the difficulty of classifying and forecasting sequences of discrete symbols, and study them in simple examples.
Photocytotoxic lanthanide complexes
Akhtar Hussain; Akhil R Chakravarty
2012-11-01
Lanthanide complexes have recently received considerable attention in the field of therapeutic and diagnostic medicines. Among many applications of lanthanides, gadolinium complexes are used as magnetic resonance imaging (MRI) contrast agents in clinical radiology and luminescent lanthanides for bioanalysis, imaging and sensing. The chemistry of photoactive lanthanide complexes showing biological applications is of recent origin. Photodynamic therapy (PDT) is a non-invasive treatment modality of cancer using a photosensitizer drug and light. This review primarily focuses on different aspects of the chemistry of lanthanide complexes showing photoactivated DNA cleavage activity and cytotoxicity in cancer cells. Macrocyclic texaphyrin-lanthanide complexes are known to show photocytotoxicity with the PDT effect in near-IR light. Very recently, non-macrocyclic lanthanide complexes are reported to show photocytotoxicity in cancer cells. Attempts have been made in this perspective article to review and highlight the photocytotoxic behaviour of various lanthanide complexes for their potential photochemotherapeutic applications.
Complex networks and computing
Shuigeng ZHOU; Zhongzhi ZHANG
2009-01-01
@@ Nowadays complex networks are pervasive in various areas of science and technology. Popular examples of complex networks include the Internet, social networks of collaboration, citations and co-authoring, as well as biological networks such as gene and protein interactions and others. Complex networks research spans across mathematics, computer science, engineering, biology and the social sciences. Even in computer science area, increasing problems are either found to be related to complex networks or studied from the perspective of complex networks, such as searching on Web and P2P networks, routing in sensor networks, language processing, software engineering etc. The interaction and mergence of complex networks and computing is inspiring new chances and challenges in computer science.
Efremov, Yu. N.; Efremov, E. Yu.
Common star complexes are huge (0.3-1 kpc in diameter) groups of relatively young stars, associations and clusters. The complexes usually form regular chains along spiral arms of grand design galaxies, being evidently formed and supported by magneto- gravitational instability developing along an arm. Special attention is given to a few large complexes which have signatures of gravitational boundness, such as round shape and high central density. Concentrations of stars and clusters in such a complex in M51 galaxy were found in this paper; we concluded it is possible to suggest that the complex is gravitationally bound. It is also stressed that some properties of the giant complex in NGC 6946 (such as its semicircular and sharp Western edge) are still enigmatic.
Simplicial complexes of graphs
Jonsson, Jakob
2008-01-01
A graph complex is a finite family of graphs closed under deletion of edges. Graph complexes show up naturally in many different areas of mathematics, including commutative algebra, geometry, and knot theory. Identifying each graph with its edge set, one may view a graph complex as a simplicial complex and hence interpret it as a geometric object. This volume examines topological properties of graph complexes, focusing on homotopy type and homology. Many of the proofs are based on Robin Forman's discrete version of Morse theory. As a byproduct, this volume also provides a loosely defined toolbox for attacking problems in topological combinatorics via discrete Morse theory. In terms of simplicity and power, arguably the most efficient tool is Forman's divide and conquer approach via decision trees; it is successfully applied to a large number of graph and digraph complexes.
How evolution guides complexity
LARRY S. YAEGER
2009-01-01
Long-standing debates about the role of natural selection in the growth of biological complexity over geological time scales are difficult to resolve from the paleobiological record. Using an evolutionary model—a computational ecosystem subjected to natural selection—we investigate evolutionary trends in an information-theoretic measure of the complexity of the neural dynamics of artificial agents inhabiting the model. Our results suggest that evolution always guides complexity change, just n...
Quantum Computational Complexity
Watrous, John
2008-01-01
This article surveys quantum computational complexity, with a focus on three fundamental notions: polynomial-time quantum computations, the efficient verification of quantum proofs, and quantum interactive proof systems. Properties of quantum complexity classes based on these notions, such as BQP, QMA, and QIP, are presented. Other topics in quantum complexity, including quantum advice, space-bounded quantum computation, and bounded-depth quantum circuits, are also discussed.
Complex Systems and Dependability
Zamojski, Wojciech; Sugier, Jaroslaw
2012-01-01
Typical contemporary complex system is a multifaceted amalgamation of technical, information, organization, software and human (users, administrators and management) resources. Complexity of such a system comes not only from its involved technical and organizational structure but mainly from complexity of information processes that must be implemented in the operational environment (data processing, monitoring, management, etc.). In such case traditional methods of reliability analysis focused mainly on technical level are usually insufficient in performance evaluation and more innovative meth
Mikos, Antonios G.; Herring, Susan W.; OCHAREON, PANNEE; Elisseeff, Jennifer; Lu, Helen H.; Kandel, Rita; Schoen, Frederick J.; Toner, Mehmet; Mooney, David; ATALA, ANTHONY; VAN DYKE, MARK E.; Kaplan, David; Vunjak-Novakovic, Gordana
2006-01-01
This article summarizes the views expressed at the third session of the workshop “Tissue Engineering—The Next Generation,” which was devoted to the engineering of complex tissue structures. Antonios Mikos described the engineering of complex oral and craniofacial tissues as a “guided interplay” between biomaterial scaffolds, growth factors, and local cell populations toward the restoration of the original architecture and function of complex tissues. Susan Herring, reviewing osteogenesis and ...
Federal Laboratory Consortium — Description/History: Engineering laboratory The Berger Lab Complex is a multi-purpose building with professional office, 100 seat auditorium, general purpose labs,...
Conducting metal dithiolate complexes
Underhill, A. E.; Ahmad, M. M.; Turner, D. J.; Clemenson, P. I.; Carneiro, K.; Yueqiuan, S.; Mortensen, Kell
Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound......Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound...
Conducting metal dithiolate complexes
Underhill, A. E.; Ahmad, M. M.; Turner, D. J.;
1985-01-01
Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound......Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound...
Y. BAR-YAM
2004-01-01
We discuss the role of scale dependence of entropy/complexity and its relationship to component interdependence. The complexity as a function of scale of observation is expressed in terms of subsystem entropies for a system having a description in terms of variables that have the same a priori scale. The sum of the complexity over all scales is the same for any system with the same number of underlying degrees of freedom (variables), even though the complexity at specific scales differs due t...
After having reported a bibliographical study on penta-methylcyclopentadienyl uranium complexes, and a description of the synthesis and radioactivity of uranium (III) and (IV) boron hydrides compounds, this research thesis reports the study of mono and bis-tetramethyl-phospholyl uranium complexes comprising chloride, boron hydride, alkyl and alkoxide ligands. The third part reports the comparison of structures, stabilities and reactions of homologue complexes in penta-methylcyclopentadienyl and tetramethyl-phospholyl series. The last part addresses the synthesis of tris-phospholyl uranium (III) and (IV) complexes.
Silverman, Richard A
1984-01-01
A shorter version of A. I. Markushevich's masterly three-volume Theory of Functions of a Complex Variable, this edition is appropriate for advanced undergraduate and graduate courses in complex analysis. Numerous worked-out examples and more than 300 problems, some with hints and answers, make it suitable for independent study. 1967 edition.
Complexity dimensions and learnability
S-H. Nienhuys-Cheng (Shan-Hwei); M. Polman
1992-01-01
textabstractA stochastic model of learning from examples has been introduced by Valiant [1984]. This PAC-learning model (PAC = probably approximately correct) reflects differences in complexity of concept classes, i.e. very complex classes are not efficiently PAC-learnable. Blumer et al. [1989] foun
H.P.P. (Hennie Lótter
1999-03-01
Full Text Available In this article an alternative philosophy of science based on ideas drawn from the study of complex adaptive systems is presented. As a result of the enormous expansion in scientific disciplines, and the number of scientists and scientific institutions in the twentieth century, I believe science can be characterised as a complex system. I want to interpret the processes of science through which scientists themselves determine what is regarded as good science. This characterisation of science as a complex system can supply an answer to the question why the sciences have been so successful in solving growing numbers of problems and correcting their own mistakes. I utilise components of complexity theory to explain and interpret science as a complex system. I first explain the concept of complexity in ordinary language. The explanation of science as a complex system starts with a definition of the basic rules guiding the behaviour of science as a complex system. Next, I indicate how various sciences have resulted through the implementation of these rules in the study of a specific aspect of reality. The explanation of the growth of science through evolutionary adaptation and learning forms the core o f the article.
Sierschynski, Jarek; Louie, Belinda; Pughe, Bronwyn
2015-01-01
One of the key requirements of Common Core State Standards (CCSS) in English Language Arts is that students are able to read and access complex texts across all grade levels. The CCSS authors emphasize both the limitations and lack of accuracy in the current CCSS model of text complexity, calling for the development of new frameworks. In response…
Freestanding Complex Optical Scanners.
Frisbie, David A.
A complex freestanding optical mark recognition (OMR) scanner is one which is not on-line to an external processor; it has intelligence stemming from an internal processor located within the unit or system. The advantages and disadvantages of a complex OMR can best be assessed after identifying the scanning needs and constraints of the potential…
Donderi, Don C.
2006-01-01
The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from…
Urban geography and complexity
Denise Pumain
2004-01-01
The contemporary approach of complex systems raises common questions that could be handled by a transdisciplinary theory. We demonstrate how the main concepts of urban geography could be integrated in such a theory ofcomplexity. We illustrate the complexity approach by a short presentationof the SIMPOP model that uses a multi-agents formalism for the simulationof the evolutionary properties of systems of cities.
Gold trifluoromethyl complexes.
Gil-Rubio, Juan; Vicente, José
2015-12-01
This article reviews the synthesis, reactivity and applications of gold trifluoromethyl complexes, which are the only isolated perfluoroalkyl complexes of gold. The most reported examples are neutral Au(i) complexes of the type [Au(CF3)L], whereas only two Au(ii) trifluoromethyl complexes have been reported, both being diamagnetic and containing a strong Au-Au bond. A number of Au(iii) trifluoromethyl complexes have been prepared by oxidative addition of halogens or iodotrifluoromethane to Au(i) complexes or, in a few cases, by transmetallation reactions. Owing to the limitations of the available synthetic methods, a lower number of examples is known, particularly for the oxidation states (ii) and (iii). Gold trifluoromethyl complexes present singular characteristics, such as thermal stability, strong Au-C bonds and, in some cases, reactive α-C-F bonds. Some of the Au(iii) complexes reported, show unusually easy reductive elimination reactions of trifluoromethylated products which could be applied in the development of gold-catalyzed processes for the trifluoromethylation of organic compounds. PMID:26169553
[Complexity: an introduction].
Gómez, Carlos Alberto Palacio; Jaramillo, Francisco Luis Ochoa
2011-01-01
Complexity appears in the twentieth century as a way to understand many phenomena that are perceived as chaotic and complex from classical thought, which still persist in our way of explaining the world. Its purpose is to study the complex and adaptive systems that are sensitive to initial conditions. Some of the characteristics of complex thought are systemic perspective, autopoiesis, self-organization, emergent properties, unpredictability of the systems, analogic thought, and the complementarity of the phenomena, among others. Living systems respond to a complex logic, and in that sense, our vision of human populations and patients, and how we try to solve problems and human diseases, should be open to the possibilities that arise from this form of understand the world. PMID:21503430
Reset Complexity of Ideal Languages
Maslennikova, Marina
2014-01-01
We present a new characteristic of a regular ideal language called reset complexity. We find some bounds on the reset complexity in terms of the state complexity of a given language. We also compare the reset complexity and the state complexity for languages related to slowly synchronizing automata and study uniqueness question for automata yielding the minimum of reset complexity.
Stable Spirocyclic Meisenheimer Complexes
Gonzalo Guirado
2008-06-01
Full Text Available Meisenheimer complexes are important intermediates in Nucleophilic Aromatic Substitution Reactions (SNAr. They are formed by the addition of electron rich species to polynitro aromatic compounds or aromatic compounds with strong electron withdrawing groups. It is possible to distinguish two types of Meisenheimer or ÃÂƒ-complexes, the ÃÂƒHcomplex or ÃÂƒX-complex (also named ipso, depending on the aromatic ring position attacked by the nucleophile (a non-substituted or substituted one, respectively. Special examples of ÃÂƒX- or ipso-complexes are formed through intermediate spiro adducts, via intramolecular SNAr. Some of these spirocyclic Meisenheimer complexes, a type of ÃÂƒXcomplex, are exceptionally stable in solution and/or as solids. They can be isolated and characterized using X-ray, and various spectroscopic techniques such as NMR, UV-Vis, IR, and fluorescence. A few of these stable spirocyclic Meisenheimer complexes are zwitterionic and exhibit interesting photophysical and redox properties. We will review recent advances, synthesis and potential applications of these stable spirocyclic Meisenheimer complexes.
Complex intuitionistic fuzzy sets
Alkouri, Abdulazeez (Moh'd. Jumah) S.; Salleh, Abdul Razak
2012-09-01
This paper presents a new concept of complex intuitionistic fuzzy set (CIFS) which is generalized from the innovative concept of a complex fuzzy set (CFS) by adding the non-membership term to the definition of CFS. The novelty of CIFS lies in its ability for membership and non-membership functions to achieve more range of values. The ranges of values are extended to the unit circle in complex plane for both membership and non-membership functions instead of [0, 1] as in the conventional intuitionistic fuzzy functions. We define basic operations namely complement, union, and intersection on CIFSs. Properties of these operations are derived.
Query complexity in expectation
Kaniewski, J.; Lee, Troy; Wolf,
2014-01-01
We study the query complexity of computing a function f:{0,1}^n-->R_+ in expectation. This requires the algorithm on input x to output a nonnegative random variable whose expectation equals f(x), using as few queries to the input x as possible. We exactly characterize both the randomized and the quantum query complexity by two polynomial degrees, the nonnegative literal degree and the sum-of-squares degree, respectively. We observe that the quantum complexity can be unboundedly smaller than t...
Complexity and forensic pathology.
Jones, Richard Martin
2015-12-01
It has become increasingly apparent that nonlinearity and complexity are the norm in human physiological systems, the relevance of which is informing an enhanced understanding of basic pathological processes such as inflammation, the host response to severe trauma, and critical illness. This article will explore how an understanding of nonlinear systems and complexity might inform the study of the pathophysiology of deaths of medicolegal interest, and how 'complexity thinking' might usefully be incorporated into modern forensic medicine and forensic pathology research, education and practice. PMID:26372537
Complexity for Artificial Substrates (
Loke, L.H.L.; Jachowski, N.R.; Bouma, T.J.; Ladle, R.J.; Todd, P.A.
2014-01-01
Physical habitat complexity regulates the structure and function of biological communities, although the mechanisms underlying this relationship remain unclear. Urbanisation, pollution, unsustainable resource exploitation and climate change have resulted in the widespread simplification (and loss) o
Yang, C.-D. [Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan (China)]. E-mail: cdyang@mail.ncku.edu.tw
2007-04-15
Tunneling dynamics and tunneling trajectories are modeled exactly by complex-extended Hamilton-Jacobi formulation in this paper. It is found that the wave-like properties of tunneling particles, such as reflection, refraction, and transmission resonance, can be identified and explained in terms of particle's motion in complex space with the tunneling time defined as the usual sense of classical time. Following the complex trajectories determined by the complex Hamilton equations of motion, we can connect classical trajectories smoothly with tunneling trajectories using position and velocity continuity at the interface of the media, locate the particle's position at any instant, and find the time spent by a particle within the potential. A microscopic tunneling model is also developed to explain the probabilistic nature why a particle with the same incident conditions sometimes transmits the potential and sometimes is reflected from the potential.
Management recommendations: Tewaukon Complex
US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Tewaukon Complex, by a land use specialist. Recommendations, time frame and additional comments are...
Federal Laboratory Consortium — This 88,000 square foot complex is used to investigate basic physical science in support of missile technology development. It incorporates office space, dedicated...
Complex coacervate core micelles.
Voets, Ilja K; de Keizer, Arie; Cohen Stuart, Martien A
2009-01-01
In this review we present an overview of the literature on the co-assembly of neutral-ionic block, graft, and random copolymers with oppositely charged species in aqueous solution. Oppositely charged species include synthetic (co)polymers of various architectures, biopolymers - such as proteins, enzymes and DNA - multivalent ions, metallic nanoparticles, low molecular weight surfactants, polyelectrolyte block copolymer micelles, metallo-supramolecular polymers, equilibrium polymers, etcetera. The resultant structures are termed complex coacervate core/polyion complex/block ionomer complex/interpolyelectrolyte complex micelles (or vesicles); i.e., in short C3Ms (or C3Vs) and PIC, BIC or IPEC micelles (and vesicles). Formation, structure, dynamics, properties, and function will be discussed. We focus on experimental work; theory and modelling will not be discussed. Recent developments in applications and micelles with heterogeneous coronas are emphasized. PMID:19038373
Moore, Cristopher
2011-11-01
In his tragically short life, Alan Turing helped define what computing machines are capable of, and where they reach inherent limits. His legacy is still felt every day, in areas ranging from computational complexity theory to cryptography and quantum computing.
On scattered subword complexity
Kása, Zoltán
2011-01-01
Special scattered subwords, in which the gaps are of length from a given set, are defined. The scattered subword complexity, which is the number of such scattered subwords, is computed for rainbow words.
none,
2012-05-01
This report documents findings from a workshop on the impacts of complex wind flows in and out of wind turbine environments, the research needs, and the challenges of meteorological and engineering modeling at regional, wind plant, and wind turbine scales.
Algorithmic Problem Complexity
Burgin, Mark
2008-01-01
People solve different problems and know that some of them are simple, some are complex and some insoluble. The main goal of this work is to develop a mathematical theory of algorithmic complexity for problems. This theory is aimed at determination of computer abilities in solving different problems and estimation of resources that computers need to do this. Here we build the part of this theory related to static measures of algorithms. At first, we consider problems for finite words and stud...
Chuang, W; Tomasiello, A; Chuang, Wu-yen; Kachru, Shamit; Tomasiello, Alessandro
2005-01-01
We construct a class of symplectic non--Kaehler and complex non--Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten--dimensional supergravity and KK reduction on SU(3)--structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds.
We construct a class of symplectic non-Kaehler and complex non-Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten-dimensional supergravity and KK reduction on SU(3)-structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds
Statistical complexity and disequilibrium
We study the concept of disequilibrium as an essential ingredient of a family of statistical complexity measures. We find that Wootters' objections to the use of Euclidean distances for probability spaces become quite relevant to this endeavor. Replacing the Euclidean distance by the Wootters' one noticeably improves the behavior of the associated statistical complexity measure, as evidenced by its application to the dynamics of the logistic map
Urban geography and complexity
Denise Pumain
2004-12-01
Full Text Available The contemporary approach of complex systems raises common questions that could be handled by a transdisciplinary theory. We demonstrate how the main concepts of urban geography could be integrated in such a theory ofcomplexity. We illustrate the complexity approach by a short presentationof the SIMPOP model that uses a multi-agents formalism for the simulationof the evolutionary properties of systems of cities.
Advances in network complexity
Dehmer, Matthias; Emmert-Streib, Frank
2013-01-01
A well-balanced overview of mathematical approaches to describe complex systems, ranging from chemical reactions to gene regulation networks, from ecological systems to examples from social sciences. Matthias Dehmer and Abbe Mowshowitz, a well-known pioneer in the field, co-edit this volume and are careful to include not only classical but also non-classical approaches so as to ensure topicality. Overall, a valuable addition to the literature and a must-have for anyone dealing with complex systems.
NUCLEAR PORE COMPLEX BIOGENESIS
Fernandez-Martinez, Javier; Rout, Michael P.
2009-01-01
Nuclear pore complexes (NPCs) are the sole mediators of transport between the nucleus and the cytoplasm. NPCs have a life cycle: they assemble, disassemble, turn over and age. The molecular mechanisms governing these different vital steps are beginning to emerge, suggesting key roles for the core structural scaffold of the NPC and auxiliary factors in the assembly of this large macromolecular complex, and connections between NPC maintenance, NPC turnover, and ageing of the cell.
Tuberous sclerosis complex is an autosomal dominant disorder with variable affection of the central nervous system (CNS) and many other organ systems. Radiological features include various lesions of the brain as well as lesions of the lungs, kidneys and the heart. Imaging is important for the early detection of complications. This article provides an overview of the clinical features and therapy as well as the specific imaging of tuberous sclerosis complex. (orig.)
Modelling Complexity in Musical Rhythm
Liou, Cheng-Yuan; Wu, Tai-Hei; Lee, Chia-Ying
2007-01-01
This paper constructs a tree structure for the music rhythm using the L-system. It models the structure as an automata and derives its complexity. It also solves the complexity for the L-system. This complexity can resolve the similarity between trees. This complexity serves as a measure of psychological complexity for rhythms. It resolves the music complexity of various compositions including the Mozart effect K488. Keyword: music perception, psychological complexity, rhythm, L-system, autom...
Hypoxia targeting copper complexes
The importance and incidence of tumour hypoxia, its measurement and current treatments available, including pharmacological and radiopharmacological methods of targeting hypoxia, are discussed. A variety of in vitro and in vivo methods for imposing hypoxia have been developed and are reviewed. Copper, its chemistry, biochemistry and radiochemistry, the potential for use of copper radionuclides and its use to date in this field is considered with particular reference to the thiosemicarbazones. Their biological activity, metal chelation, in vitro and in vivo studies of their radiocopper complexes and the potential for their use as hypoxia targeting radiopharmaceuticals is described. The reduction of the copper(II) complex to copper(l), its pivotal importance in their biological behaviour, and the potential for manipulation of this to effect hypoxia selectivity are described. An in vitro method for assessing the hypoxia selectivity of radiopharmaceuticals is reported. The rapid deoxygenation and high viability of a mammalian cell culture in this system is discussed and factors which may affect the cellular uptake of a radiopharmaceutical are described. The design, synthesis and complexation with copper and radiocopper of a range of bis(thiosemicarbazones) is reported. Synthesis of these compounds is simple giving high yields of pure products. The characteristics of the radiocopper complexes (64Cu) including lipophilicity and redox activity are reported (reduction potentials in the range -0.314 - -0.590 V). High cellular uptakes of the radiocopper complexes of the ligands, in hypoxic and normoxic EMT6 and CHO320 cells, were observed. Extremes of selectivity are shown ranging from the hypoxia selective 64Cu(II)ATSM to normoxic cell selective 64Cu(II)GTS. The selectivities observed are compared with the physico chemical characteristics of the complexes. A good correlation exists between selectivity of the complex and its Cu(II)/Cu(I) reduction potential, with hypoxia
Hypoxia targeting copper complexes
Dearling, J.L
1998-11-01
The importance and incidence of tumour hypoxia, its measurement and current treatments available, including pharmacological and radiopharmacological methods of targeting hypoxia, are discussed. A variety of in vitro and in vivo methods for imposing hypoxia have been developed and are reviewed. Copper, its chemistry, biochemistry and radiochemistry, the potential for use of copper radionuclides and its use to date in this field is considered with particular reference to the thiosemicarbazones. Their biological activity, metal chelation, in vitro and in vivo studies of their radiocopper complexes and the potential for their use as hypoxia targeting radiopharmaceuticals is described. The reduction of the copper(II) complex to copper(l), its pivotal importance in their biological behaviour, and the potential for manipulation of this to effect hypoxia selectivity are described. An in vitro method for assessing the hypoxia selectivity of radiopharmaceuticals is reported. The rapid deoxygenation and high viability of a mammalian cell culture in this system is discussed and factors which may affect the cellular uptake of a radiopharmaceutical are described. The design, synthesis and complexation with copper and radiocopper of a range of bis(thiosemicarbazones) is reported. Synthesis of these compounds is simple giving high yields of pure products. The characteristics of the radiocopper complexes ({sup 64}Cu) including lipophilicity and redox activity are reported (reduction potentials in the range -0.314 - -0.590 V). High cellular uptakes of the radiocopper complexes of the ligands, in hypoxic and normoxic EMT6 and CHO320 cells, were observed. Extremes of selectivity are shown ranging from the hypoxia selective {sup 64}Cu(II)ATSM to normoxic cell selective {sup 64}Cu(II)GTS. The selectivities observed are compared with the physico chemical characteristics of the complexes. A good correlation exists between selectivity of the complex and its Cu(II)/Cu(I) reduction potential
This work deals with some of the most typical complexes of interstellar matter and presents a holistic view of the well studied complexes in Orion, built on information derived from various branches of modern astrophysics. A wealth of published data is presented in the form of photographs, contour maps, diagrams and numerous heavily annotated tables. Chapter 1, which is concerned with the large scale view of the Orion region, outlines the morphology of the area and examines in particular the nature of Barnard's Loop and the associated filamentary structure in addition to the origin of the I Orion OB association. Chapter 2 focuses on the Great Orion Nebula (M42 or NGC 1976) and the small H II region to the north (M43 or NGC 1982). Chapter 3 examines the Orion Complex as a whole, i.e. the H II regions M42 and M43, the associated molecular clouds OMC 1 and OMC 2 and their interrelations. Chapter 4 contains a discussion of the empirical models introduced to attempt to explain certain aspects of this very complex region, and chapter 5 investigates the second prominent H II region and molecular cloud complex, NGC 2024 (Orion B, W12). (Auth.)
Algorithmic Relative Complexity
Daniele Cerra
2011-04-01
Full Text Available Information content and compression are tightly related concepts that can be addressed through both classical and algorithmic information theories, on the basis of Shannon entropy and Kolmogorov complexity, respectively. The definition of several entities in Kolmogorov’s framework relies upon ideas from classical information theory, and these two approaches share many common traits. In this work, we expand the relations between these two frameworks by introducing algorithmic cross-complexity and relative complexity, counterparts of the cross-entropy and relative entropy (or Kullback-Leibler divergence found in Shannon’s framework. We define the cross-complexity of an object x with respect to another object y as the amount of computational resources needed to specify x in terms of y, and the complexity of x related to y as the compression power which is lost when adopting such a description for x, compared to the shortest representation of x. Properties of analogous quantities in classical information theory hold for these new concepts. As these notions are incomputable, a suitable approximation based upon data compression is derived to enable the application to real data, yielding a divergence measure applicable to any pair of strings. Example applications are outlined, involving authorship attribution and satellite image classification, as well as a comparison to similar established techniques.
Complexity of Economical Systems
G. P. Pavlos
2015-01-01
Full Text Available In this study new theoretical concepts are described concerning the interpretation of economical complex dynamics. In addition a summary of an extended algorithm of nonlinear time series analysis is provided which is applied not only in economical time series but also in other physical complex systems (e.g. [22, 24]. In general, Economy is a vast and complicated set of arrangements and actions wherein agents—consumers, firms, banks, investors, government agencies—buy and sell, speculate, trade, oversee, bring products into being, offer services, invest in companies, strategize, explore, forecast, compete, learn, innovate, and adapt. As a result the economic and financial variables such as foreign exchange rates, gross domestic product, interest rates, production, stock market prices and unemployment exhibit large-amplitude and aperiodic fluctuations evident in complex systems. Thus, the Economics can be considered as spatially distributed non-equilibrium complex system, for which new theoretical concepts, such as Tsallis non extensive statistical mechanics and strange dynamics, percolation, nonGaussian, multifractal and multiscale dynamics related to fractional Langevin equations can be used for modeling and understanding of the economical complexity locally or globally.
Complexity: The bigger picture
Vicsek, Tamás
2010-01-01
If a concept is not well defined, there are grounds for its abuse. This is particularly true of complexity, an inherently interdisciplinary concept that has penetrated very different fields of intellectual activity from physics to linguistics, but with no underlying, unified theory. Complexity has become a popular buzzword used in the hope of gaining attention or funding -- institutes and research networks associated with complex systems grow like mushrooms. Why and how did it happen that this vague notion has become a central motif in modern science? Is it only a fashion, a kind of sociological phenomenon, or is it a sign of a changing paradigm of our perception of the laws of nature and of the approaches required to understand them? Because virtually every real system is inherently extremely complicated, to say that a system is complex is almost an empty statement - couldn't an Institute of Complex Systems just as well be called an Institute for Almost Everything? Despite these valid concerns, the world is ...
Synchronization in complex networks
Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C.; Kurths, J.
2007-12-12
Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.
Introduction to Complex Plasmas
Bonitz, Michael; Ludwig, Patrick
2010-01-01
Complex plasmas differ from traditional plasmas in many ways: these are low-temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum behaviour. These interesting properties have led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists and experienced undergraduates.
Thiosemicarbazone complexes of technetium
One aproach to the design of new sup(99m)Tc-radiopharmaceuticals consists in the preparation of bifunctional radio-pharmaceuticals [1]. In this approach, a bifunctional molecule is synthesized which possesses a chelating functional group (capable of forming a stable complex with sup(99m)Tc) attached to a second functional group which is expected to have a useful biological distribution. Thiosemicarbazones are compounds that possess great chelating capacity [2] and are easily obtainable by condensation of the theosemicarbazide (H2N-NH-CS-NH2) or substituted thiosemicarbazide with the carbonyl groups of aldehydes or ketones. Consequently transformation of molecules of biological interest that the carbonyl group possess in thiosemicarbazones is simple and these modified molecules could act a bifunctional radiopharmaceuticals. For this reason a series of thiosemicarbazone complexes of 99Tc was prepared. This is the first report on technetium complexes with thiosemicarbazones. (orig.)
Thiosemicarbazone complexes of technetium
Grases, F.; Genestar, C.
1985-01-01
One aproach to the design of new sup(99m)Tc-radiopharmaceuticals consists in the preparation of bifunctional radio-pharmaceuticals (1). In this approach, a bifunctional molecule is synthesized which possesses a chelating functional group (capable of forming a stable complex with sup(99m)Tc) attached to a second functional group which is expected to have a useful biological distribution. Thiosemicarbazones are compounds that possess great chelating capacity (2) and are easily obtainable by condensation of the theosemicarbazide (H/sub 2/N-NH-CS-NH/sub 2/) or substituted thiosemicarbazide with the carbonyl groups of aldehydes or ketones. Consequently transformation of molecules of biological interest that the carbonyl group possess in thiosemicarbazones is simple and these modified molecules could act as bifunctional radiopharmaceuticals. For this reason a series of thiosemicarbazone complexes of /sup 99/Tc was prepared. This is the first report on technetium complexes with thiosemicarbazones.
Nonergodic complexity management
Piccinini, Nicola; Lambert, David; West, Bruce J.; Bologna, Mauro; Grigolini, Paolo
2016-06-01
Linear response theory, the backbone of nonequilibrium statistical physics, has recently been extended to explain how and why nonergodic renewal processes are insensitive to simple perturbations, such as in habituation. It was established that a permanent correlation results between an external stimulus and the response of a complex system generating nonergodic renewal processes, when the stimulus is a similar nonergodic process. This is the principle of complexity management, whose proof relies on ensemble distribution functions. Herein we extend the proof to the nonergodic case using time averages and a single time series, hence making it usable in real life situations where ensemble averages cannot be performed because of the very nature of the complex systems being studied.
Emergent Complex Network Geometry
Wu, Zhihao; Rahmede, Christoph; Bianconi, Ginestra
2014-01-01
Networks are mathematical structures that are universally used to describe a large variety of complex systems such as the brain or the Internet. Characterizing the geometrical properties of these networks has become increasingly relevant for routing problems, inference and data mining. In real growing networks, topological, structural and geometrical properties emerge spontaneously from their dynamical rules. Nevertheless we still miss a model in which networks develop an emergent complex geometry. Here we show that a single two parameter network model, the growing geometrical network, can generate complex network geometries with non-trivial distribution of curvatures, combining exponential growth and small-world properties with finite spectral dimensionality. In one limit, the non-equilibrium dynamical rules of these networks can generate scale-free networks with clustering and communities, in another limit planar random geometries with non-trivial modularity. Finally we find that these properties of the geo...
Viral quasispecies complexity measures.
Gregori, Josep; Perales, Celia; Rodriguez-Frias, Francisco; Esteban, Juan I; Quer, Josep; Domingo, Esteban
2016-06-01
Mutant spectrum dynamics (changes in the related mutants that compose viral populations) has a decisive impact on virus behavior. The several platforms of next generation sequencing (NGS) to study viral quasispecies offer a magnifying glass to study viral quasispecies complexity. Several parameters are available to quantify the complexity of mutant spectra, but they have limitations. Here we critically evaluate the information provided by several population diversity indices, and we propose the introduction of some new ones used in ecology. In particular we make a distinction between incidence, abundance and function measures of viral quasispecies composition. We suggest a multidimensional approach (complementary information contributed by adequately chosen indices), propose some guidelines, and illustrate the use of indices with a simple example. We apply the indices to three clinical samples of hepatitis C virus that display different population heterogeneity. Areas of virus biology in which population complexity plays a role are discussed. PMID:27060566
Owladeghaffari, Hamed
2009-01-01
A complex network approach on a rough fracture is developed. In this manner, some hidden metric spaces (similarity measurements) between apertures profiles are set up and a general evolutionary network in two directions (in parallel and perpendicular to the shear direction) is constructed. Evaluation of the emerged network shows the connectivity degree (distribution) of network, after a transition step; fall in to the stable states which are coincided with the Gaussian distribution. Based on this event and real observations of the complex network changes, an algorithm (COmplex Networks on Apertures: CONA) is proposed in which evolving of a network is accomplished using preferential detachments and attachments of edges (based on a competition and game manner) while the number of nodes is fixed. Also, evolving of clustering coefficients and number of edges display similar patterns as well as are appeared in shear stress, hydraulic conductivity and dilation changes, which can be engaged to estimate shear strengt...
Baldi, Pierre; Lu, Zhiqin
2011-01-01
Autoencoders are unsupervised machine learning circuits whose learning goal is to minimize a distortion measure between inputs and outputs. Linear autoencoders can be defined over any field and only real-valued linear autoencoder have been studied so far. Here we study complex-valued linear autoencoders where the components of the training vectors and adjustable matrices are defined over the complex field with the $L_2$ norm. We provide simpler and more general proofs that unify the real-valued and complex-valued cases, showing that in both cases the landscape of the error function is invariant under certain groups of transformations. The landscape has no local minima, a family of global minima associated with Principal Component Analysis, and many families of saddle points associated with orthogonal projections onto sub-space spanned by sub-optimal subsets of eigenvectors of the covariance matrix. The theory yields several iterative, convergent, learning algorithms, a clear understanding of the generalizatio...
2011-01-01
The domain of nonlinear dynamical systems and its mathematical underpinnings has been developing exponentially for a century, the last 35 years seeing an outpouring of new ideas and applications and a concomitant confluence with ideas of complex systems and their applications from irreversible thermodynamics. A few examples are in meteorology, ecological dynamics, and social and economic dynamics. These new ideas have profound implications for our understanding and practice in domains involving complexity, predictability and determinism, equilibrium, control, planning, individuality, responsibility and so on. Our intention is to draw together in this volume, we believe for the first time, a comprehensive picture of the manifold philosophically interesting impacts of recent developments in understanding nonlinear systems and the unique aspects of their complexity. The book will focus specifically on the philosophical concepts, principles, judgments and problems distinctly raised by work in the domain of comple...
Boccara, Nino
2010-01-01
Modeling Complex Systems, 2nd Edition, explores the process of modeling complex systems, providing examples from such diverse fields as ecology, epidemiology, sociology, seismology, and economics. It illustrates how models of complex systems are built and provides indispensable mathematical tools for studying their dynamics. This vital introductory text is useful for advanced undergraduate students in various scientific disciplines, and serves as an important reference book for graduate students and young researchers. This enhanced second edition includes: . -recent research results and bibliographic references -extra footnotes which provide biographical information on cited scientists who have made significant contributions to the field -new and improved worked-out examples to aid a student’s comprehension of the content -exercises to challenge the reader and complement the material Nino Boccara is also the author of Essentials of Mathematica: With Applications to Mathematics and Physics (Springer, 2007).
Synchronization in complex networks
Arenas, Alex; Díaz-Guilera, Albert; Kurths, Jurgen; Moreno, Yamir; Zhou, Changsong
2008-12-01
Synchronization processes in populations of locally interacting elements are the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understanding synchronization phenomena in natural systems now take advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also take an overview of the new emergent features coming out from the interplay between the structure and the function of the underlying patterns of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.
A description is given of the structure, input procedure and recording rules of initial data for the BRAND programme complex intended for the Monte Carlo simulation of neutron physics experiments. The BRAND complex ideology is based on non-analogous simulation of the neutron and photon transport process (statistic weights are used, absorption and escape of particles from the considered region is taken into account, shifted readouts from a coordinate part of transition nucleus density are applied, local estimations, etc. are used). The preparation of initial data for three sections is described in detail: general information for Monte Carlo calculation, source definition and data for describing the geometry of the system. The complex is to be processed with the BESM-6 computer, the basic programming lan-- guage is FORTRAN, volume - more than 8000 operators
Complex Polynomial Vector Fields
Dias, Kealey
The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions or...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields....
Leleur, Steen
. Complex Strategic Choices provides clear principles and methods which can guide and support strategic decision making to face the many current challenges. By considering ways in which planning practices can be renewed and exploring the possibilities for acquiring awareness and tools to add value to...... resulting in new material stemming from and focusing on practical application of a systemic approach. The outcome is a coherent and flexible approach named systemic planning. The inclusion of both the theoretical and practical aspects of systemic planning makes this book a key resource for researchers and...... students in the field of planning and decision analysis as well as practitioners dealing with strategic analysis and decision making. More broadly, Complex Strategic Choices acts as guide for professionals and students involved in complex planning tasks across several fields such as business and...
In this paper, GAO provides its views on DOE's January 1991 Nuclear Weapons Complex Reconfiguration Study. GAO believes that DOE's new reconfiguration study provides a starting point for reaching agreement on solutions to many of the complex's problems. Key decisions still need to be made about the size of the complex, where to relocate plutonium operations, what technologies should be used for new tritium production, and what to do with excess plutonium. The total cost for reconfiguring and modernizing is still uncertain and some management issues remain unresolved. Congress faces a difficult task in making these decisions given the conflicting demands for scare resources in a time of growing budget deficits and war in the Persian Gulf
Ilona Koutny
2015-04-01
Full Text Available The long accepted complexity invariance of human languages has become controversial within the last decade. In investigations of the problem, both creole and planned languages have often been neglected. After a presentation of the scope of the invariance problem and the proposition of the natural to planned language continuum, this article will discuss the contribution of planned languages. It will analyze the complexity of Esperanto at the phonological, morphological, syntactic and semantic levels, using linguistic data bases. The role of the L2 speech community and development of the language will also be taken into account when discussing the endurance of the same level of simplicity of this planned international language. The author argues that complexity can be variable and to some extent planned and maintained.
Oleg Svatos
2013-01-01
Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.
Management of complex fisheries
Frost, Hans Staby; Andersen, Peder; Hoff, Ayoe
2013-01-01
The purpose of this paper is to demonstrate how fisheries economics management issues or problems can be analyzed by using a complex model based on conventional bioeconomic theory. Complex simulation models contain a number of details that make them suitable for practical management advice......, including taking into account the response of the fishermen to implemented management measures. To demonstrate the use of complex management models this paper assesses a number of second best management schemes against a first rank optimum (FRO), an ideal individual transferable quotas (ITQ) system....... This is defined as the management scheme which produces the highest net present value over a 25 year period. The assessed management schemes (scenarios) are composed by several measures as used in the Common Fisheries Policy of the European Union for the cod fishery in the Baltic Sea. The scenarios are total...
Chuang, Wu-yen; Kachru, Shamit; /Stanford U., ITP /SLAC; Tomasiello, Alessandro; /Stanford U., ITP
2005-10-28
We construct a class of symplectic non-Kaehler and complex non-Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten-dimensional supergravity and KK reduction on SU(3)-structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds.
Cates, Grant; Murray, Joelle
Complexity is the study of phenomena that emerge from a collection of interacting objects and arises in many systems throughout physics, biology, finance, economics and more. Certain kinds of complex systems can be described by self-organized criticality (SOC). An SOC system is one that is internally driven towards some critical state. Recent experimental work suggests scaling behavior of fly swarms-one of the hallmarks of an SOC system. Our goal is to look for SOC behavior in computational models of fly swarms.
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.)
Luminescent macrocyclic lanthanide complexes
Raymond, Kenneth N.; Corneillie, Todd M.; Xu, Jide
2012-05-08
The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.
Complex variables II essentials
Solomon, Alan D
2013-01-01
REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Complex Variables II includes elementary mappings and Mobius transformation, mappings by general functions, conformal mappings and harmonic functions, applying complex functions to a
Complexity in Managing Modularization
Hansen, Poul H. Kyvsgård; Sun, Hongyi
2011-01-01
In general, the phenomenon of managing modularization is not well known. The cause-effect relationships between modularization and realized benefits are complex and comprehensive. Though a number of research works have contributed to the study of the phenomenon of efficient and effective modulari......In general, the phenomenon of managing modularization is not well known. The cause-effect relationships between modularization and realized benefits are complex and comprehensive. Though a number of research works have contributed to the study of the phenomenon of efficient and effective...
Nonlinear dynamics and complexity
Luo, Albert; Fu, Xilin
2014-01-01
This important collection presents recent advances in nonlinear dynamics including analytical solutions, chaos in Hamiltonian systems, time-delay, uncertainty, and bio-network dynamics. Nonlinear Dynamics and Complexity equips readers to appreciate this increasingly main-stream approach to understanding complex phenomena in nonlinear systems as they are examined in a broad array of disciplines. The book facilitates a better understanding of the mechanisms and phenomena in nonlinear dynamics and develops the corresponding mathematical theory to apply nonlinear design to practical engineering.
Theories of computational complexity
Calude, C
1988-01-01
This volume presents four machine-independent theories of computational complexity, which have been chosen for their intrinsic importance and practical relevance. The book includes a wealth of results - classical, recent, and others which have not been published before.In developing the mathematics underlying the size, dynamic and structural complexity measures, various connections with mathematical logic, constructive topology, probability and programming theories are established. The facts are presented in detail. Extensive examples are provided, to help clarify notions and constructions. The lists of exercises and problems include routine exercises, interesting results, as well as some open problems.
Deformable Simplicial Complexes
Misztal, Marek Krzysztof
In this dissertation we present a novel method for deformable interface tracking in 2D and 3D|deformable simplicial complexes (DSC). Deformable interfaces are used in several applications, such as fluid simulation, image analysis, reconstruction or structural optimization. In the DSC method, the...... triangles/tetrahedra marked as outside from those marked as inside. Such an approach allows for robust topological adaptivity. Among other advantages of the deformable simplicial complexes there are: space adaptivity, ability to handle and preserve sharp features, possibility for topology control. We...
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.)
Supporting complex search tasks
Gäde, Maria; Hall, Mark; Huurdeman, Hugo;
2015-01-01
fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...... introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing...
Dettman, John W
1965-01-01
Analytic function theory is a traditional subject going back to Cauchy and Riemann in the 19th century. Once the exclusive province of advanced mathematics students, its applications have proven vital to today's physicists and engineers. In this highly regarded work, Professor John W. Dettman offers a clear, well-organized overview of the subject and various applications - making the often-perplexing study of analytic functions of complex variables more accessible to a wider audience. The first half of Applied Complex Variables, designed for sequential study, is a step-by-step treatment of fun
Introduction to complex analysis
Priestley, H A
2003-01-01
Complex analysis is a classic and central area of mathematics, which is studied and exploited in a range of important fields, from number theory to engineering. Introduction to Complex Analysis was first published in 1985, and for this much awaited second edition the text has been considerably expanded, while retaining the style of the original. More detailed presentation is given of elementary topics, to reflect the knowledge base of current students. Exercise sets have beensubstantially revised and enlarged, with carefully graded exercises at the end of each chapter.This is the latest additi
Salen complexes with dianionic counterions
Job, Gabriel E.; Farmer, Jay J.; Cherian, Anna E.
2016-08-02
The present invention describes metal salen complexes having dianionic counterions. Such complexes can be readily precipitated and provide an economical method for the purification and isolation of the complexes, and are useful to prepare novel polymer compositions.
Genetics Home Reference: Carney complex
... Understand Genetics Home Health Conditions Carney complex Carney complex Enable Javascript to view the expand/collapse boxes. Print All Open All Close All Description Carney complex is a disorder characterized by an increased risk ...
"Product Complexity and Economic Development"
Abdon, Arnelyn; Bacate, Marife; Felipe, Jesus; Kumar, Utsav
2010-01-01
We rank 5,107 products and 124 countries according to the Hidalgo and Hausmann (2009) measures of complexity. We find that: (1) the most complex products are in machinery, chemicals, and metals, while the least complex products are raw materials and commodities, wood, textiles, and agricultural products; (2) the most complex economies in the world are Japan, Germany, and Sweden, and the least complex, Cambodia, Papua New Guinea, and Nigeria; (3) the major exporters of the more complex product...
Managing Complex Dynamical Systems
Cox, John C.; Webster, Robert L.; Curry, Jeanie A.; Hammond, Kevin L.
2011-01-01
Management commonly engages in a variety of research designed to provide insight into the motivation and relationships of individuals, departments, organizations, etc. This paper demonstrates how the application of concepts associated with the analysis of complex systems applied to such data sets can yield enhanced insights for managerial action.
Petronio, Carlo
2004-01-01
We extend Matveev's theory of complexity for 3-manifolds, based on simple spines, to (closed, orientable, locally orientable) 3-orbifolds. We prove naturality and finiteness for irreducible 3-orbifolds, and, with certain restrictions and subtleties, additivity under orbifold connected sum. We also develop the theory of handle decompositions for 3-orbifolds and the corresponding theory of normal 2-suborbifolds.
Mei, Shengwei; Cao, Ming
2011-01-01
This book introduces self-organized criticality (SOC) theory and complex network theory and applies them to power systems. It examines four blackout models based on SOC theory and studies the SOC of power systems at both the macroscopic and microscopic levels.
Complex Digital Visual Systems
Sweeny, Robert W.
2013-01-01
This article identifies possibilities for data visualization as art educational research practice. The author presents an analysis of the relationship between works of art and digital visual culture, employing aspects of network analysis drawn from the work of Barabási, Newman, and Watts (2006) and Castells (1994). Describing complex network…
De Melis, Cinzia
2016-01-01
The LHC is the last ring (dark blue line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.
Fratalocchi, Andrea
2014-12-01
Disorder and chaos are ubiquitous phenomena that are mostly unwanted in applications. On the contrary, they can be exploited to create a new technology. In this talk I will summarize my research in this field, discussing chaotic energy harvesting, nonlinear stochastic resonance and complex nanolasers.
Psychopathology and complexity
Leonardo Y. Álvarez R
2010-08-01
Full Text Available The paradigm of complexity states that reality conveys a chaotic dynamics, ambiguous, blurred, and paradoxical, and that it does not fulfill the values of order, harmony nor perfection. However, such a chaos represents a specific way of organization and order. Human behavior explained by this paradigm vindicates on this way the outstanding role of contradiction and irregularity aside of what is linear and predictable. The purpose of this review has the primary aim to describe some concepts and assumptions that give support to the approach to complexity in behavior, especially concerning the psychopathological behavior of an individual. Some comparisons with concepts associated to complexity in scientific approaches to psychology (contextual and paradigmatical behaviorism and interbehaviorism from its own persepctive are stablished. All these elements are developed underlining the concepts of reciprocal multicausality, complex and hierarchical learning, historical and contextual factors in the comprehension of behavior, and trying to make some extrapolations on the psychopathological behavior. This approach is hence considered appropriate and necessary to understand gnosiological entities and to intervene them in their role of clinical challenges.
Tevatron's complex collider cousins
Fischer, W
2004-01-01
Letter referring to Schwarzschild's story "Disappointing performance and tight budgets confront Fermilab with tough decisions" and contesting that the Tevatron is not the most complex accelerator operating. They use the examples of CERN's SPS collider, HERA at DESY and the RHIC at Brookhaven (1/4 page)
Rosendahl, Mads
1989-01-01
One way to analyse programs is to to derive expressions for their computational behaviour. A time bound function (or worst-case complexity) gives an upper bound for the computation time as a function of the size of input. We describe a system to derive such time bounds automatically using abstract...
Hendil, Klavs B; Hartmann-Petersen, Rasmus
2004-01-01
Protein degradation in eukaryotic cells is important for regulation of metabolism, progression through the division cycle, in cell signalling pathways, and in mammals also for generation of antigen fragments for presentation on the major histocompatibility complex (MHC) class I. Most cell proteins...
Complex Interfaces Under Change
Rosbjerg, Dan
mechanical processes that develop within this structure. Water-related processes at the interfaces between the compartments are complex, depending both on the interface itself, and on the characteristics of the interfaced compartments. Various aspects of global change directly or indirectly impact these...
Dynamic and topological complexity
Turalska, Malgorzata; Geneston, Elvis; Grigolini, Paolo
2010-03-01
Cooperative phenomena in complex networks are expected to display unusual characteristics, associated with the peculiar topology of these systems. In this context we study networks of interacting stochastic two-state units as a model of cooperative decision making. Each unit in isolation generates a Poisson process with rate g. We show that when the cooperation is introduced, the decision-making process becomes intermittent. The decision-time distribution density characterized by inverse power-law behavior is defined as a dynamic complexity. Further, the onset of intermittency, expressed in terms of the coupling parameter K, is used as a measure of dynamic efficiency of investigated topologies. We find that the dynamic complexity emerges from regular and small-world topologies. In contrast, both random and scale-free networks correspond to fast transition into exponential decision-time distribution. This property is accompanied by high dynamic efficiency of the decision-making process. Our results indicate that complex dynamical processes occurring on networks could be related to relatively simple topologies.
贾燕梅
2007-01-01
Being as one figurative form of language, metaphor plays the most complicated role to make language colorful and vivid.Demonstrating the types and the features of metaphor, this article will focus on the point that metaphor is a complex language phenomenon heavily loaded with the factor of culture.
Haffner, Julie
2013-01-01
The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.
Christiane Lefèvre
2008-01-01
The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.
Statistical electromagnetics: Complex cavities
Naus, H.W.L.
2008-01-01
A selection of the literature on the statistical description of electromagnetic fields and complex cavities is concisely reviewed. Some essential concepts, for example, the application of the central limit theorem and the maximum entropy principle, are scrutinized. Implicit assumptions, biased choic
Lanthanide porphyrin complexes
The review summarizes literature data and results of the author's research on the synthesis, properties and possible fields of practical application of lanthanide porphyrin complexes. Emphasis is given to the application of luminescence properties of lanthanide derivatives in medicine. The bibliography includes 108 references.
Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.
2012-01-01
Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…
Angel Garrido
2011-01-01
Full Text Available In this paper, we analyze a few interrelated concepts about graphs, such as their degree, entropy, or their symmetry/asymmetry levels. These concepts prove useful in the study of different types of Systems, and particularly, in the analysis of Complex Networks. A System can be defined as any set of components functioning together as a whole. A systemic point of view allows us to isolate a part of the world, and so, we can focus on those aspects that interact more closely than others. Network Science analyzes the interconnections among diverse networks from different domains: physics, engineering, biology, semantics, and so on. Current developments in the quantitative analysis of Complex Networks, based on graph theory, have been rapidly translated to studies of brain network organization. The brain's systems have complex network features—such as the small-world topology, highly connected hubs and modularity. These networks are not random. The topology of many different networks shows striking similarities, such as the scale-free structure, with the degree distribution following a Power Law. How can very different systems have the same underlying topological features? Modeling and characterizing these networks, looking for their governing laws, are the current lines of research. So, we will dedicate this Special Issue paper to show measures of symmetry in Complex Networks, and highlight their close relation with measures of information and entropy.
Interdisciplinary Symposium on Complex Systems
Rössler, Otto; Zelinka, Ivan
2015-01-01
The book you hold in your hands is the outcome of the “2014 Interdisciplinary Symposium on Complex Systems” held in the historical city of Florence. The book consists of 37 chapters from 4 areas of Physical Modeling of Complex Systems, Evolutionary Computations, Complex Biological Systems and Complex Networks. All 4 parts contain contributions that give interesting point of view on complexity in different areas in science and technology. The book starts with a comprehensive overview and classification of complexity problems entitled Physics in the world of ideas: Complexity as Energy” , followed by chapters about complexity measures and physical principles, its observation, modeling and its applications, to solving various problems including real-life applications. Further chapters contain recent research about evolution, randomness and complexity, as well as complexity in biological systems and complex networks. All selected papers represent innovative ideas, philosophical overviews and state-of-the-...
Cohomological decomposition of complex nilmanifolds
Latorre, Adela; Ugarte, Luis
2015-01-01
We study pureness and fullness of invariant complex structures on nilmanifolds. We prove that in dimension six, apart from the complex torus, there exist only two non-isomorphic complex structures satisfying both properties, which live on the real nilmanifold underlying the Iwasawa manifold. We also show that the product of two almost complex manifolds which are pure and full is not necessarily full.
Stable generalized complex structures
Cavalcanti, Gil R
2015-01-01
A stable generalized complex structure is one that is generically symplectic but degenerates along a real codimension two submanifold, where it defines a generalized Calabi-Yau structure. We introduce a Lie algebroid which allows us to view such structures as symplectic forms. This allows us to construct new examples of stable structures, and also to define period maps for their deformations in which the background three-form flux is either fixed or not, proving the unobstructedness of both deformation problems. We then use the same tools to establish local normal forms for the degeneracy locus and for Lagrangian branes. Applying our normal forms to the four-dimensional case, we prove that any compact stable generalized complex 4-manifold has a symplectic completion, in the sense that it can be modified near its degeneracy locus to produce a compact symplectic 4-manifold.
Hazelett, Dennis J; Conti, David V; Han, Ying; Al Olama, Ali Amin; Easton, Doug; Eeles, Rosalind A; Kote-Jarai, Zsofia; Haiman, Christopher A; Coetzee, Gerhard A
2016-01-01
Genome-wide association studies (GWAS) have revealed numerous genomic 'hits' associated with complex phenotypes. In most cases these hits, along with surrogate genetic variation as measure by numerous single nucleotide polymorphisms (SNPs) that are in linkage disequilibrium, are not in coding genes making assignment of functionality or causality intractable. Here we propose that fine-mapping along with the matching of risk SNPs at chromatin biofeatures lessen this complexity by reducing the number of candidate functional/causal SNPs. For example, we show here that only on average 2 SNPs per prostate cancer risk locus are likely candidates for functionality/causality; we further propose that this manageable number should be taken forward in mechanistic studies. The candidate SNPs can be looked up for each prostate cancer risk region in 2 recent publications in 2015 (1,2) from our groups. PMID:26771711
Francesco Caddeo
2014-08-01
Full Text Available The reaction of the ligand Et4todit (4,5,6,7-Tetrathiocino-[1,2-b:3,4-b']-diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione with gold complexes leads to the dinuclear gold(I complexes [{Au(C6F5}2(Et4todit] and [Au(Et4todit]2(OTf2, which do not contain any gold-gold interactions, or to the gold(III derivative [{Au(C6F53}2(Et4todit]. The crystal structures have been established by X-ray diffraction studies and show that the gold centers coordinate to the sulfur atoms of the imidazoline-2-thione groups.
Complex Polynomial Vector Fields
Dias, Kealey
The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions or...... meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...
Dahlberg, Rasmus
2015-01-01
This paper explores two key concepts: resilience and complexity. The first is understood as an emergent property of the latter, and their inter-relatedness is discussed using a three tier approach. First, by exploring the discourse of each concept, next, by analyzing underlying relationships and......, finally, by presenting the Cynefin Framework for Sense-Making as a tool of explicatory potential that has already shown its usefulness in several contexts. I further emphasize linking the two concepts into a common and, hopefully, useful concept. Furthermore, I argue that a resilient system is not merely...... robust. Robustness is a property of simple or complicated systems characterized by predictable behavior, enabling the system to bounce back to its normal state following a perturbation. Resilience, however, is an emergent property of complex adaptive systems. It is suggested that this distinction is...
Polystochastic Models for Complexity
Iordache, Octavian
2010-01-01
This book is devoted to complexity understanding and management, considered as the main source of efficiency and prosperity for the next decades. Divided into six chapters, the book begins with a presentation of basic concepts as complexity, emergence and closure. The second chapter looks to methods and introduces polystochastic models, the wave equation, possibilities and entropy. The third chapter focusing on physical and chemical systems analyzes flow-sheet synthesis, cyclic operations of separation, drug delivery systems and entropy production. Biomimetic systems represent the main objective of the fourth chapter. Case studies refer to bio-inspired calculation methods, to the role of artificial genetic codes, neural networks and neural codes for evolutionary calculus and for evolvable circuits as biomimetic devices. The fifth chapter, taking its inspiration from systems sciences and cognitive sciences looks to engineering design, case base reasoning methods, failure analysis, and multi-agent manufacturing...
Francesco Caddeo; Vanesa Fernández-Moreira; Massimiliano Arca; Antonio Laguna; Vito Lippolis; M. Concepción Gimeno
2014-01-01
The reaction of the ligand Et4todit (4,5,6,7-Tetrathiocino-[1,2-b:3,4-b']-diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione) with gold complexes leads to the dinuclear gold(I) complexes [{Au(C6F5)}2(Et4todit)] and [Au(Et4todit)]2(OTf)2, which do not contain any gold-gold interactions, or to the gold(III) derivative [{Au(C6F5)3}2(Et4todit)]. The crystal structures have been established by X-ray diffraction studies and show that the gold centers coordinate to the sulfur atoms of the imidazoline-2-t...
Chatterjee, Krishnendu; Majumdar, Rupak
2008-01-01
We study the problem of generating a test sequence that achieves maximal coverage for a reactive system under test. We formulate the problem as a repeated game between the tester and the system, where the system state space is partitioned according to some coverage criterion and the objective of the tester is to maximize the set of partitions (or coverage goals) visited during the game. We show the complexity of the maximal coverage problem for non-deterministic systems is PSPACE-complete, but is NP-complete for deterministic systems. For the special case of non-deterministic systems with a re-initializing ``reset'' action, which represent running a new test input on a re-initialized system, we show that the complexity is again co-NP-complete. Our proof technique for reset games uses randomized testing strategies that circumvent the exponentially large memory requirement in the deterministic case.
Jalali, Shirin
2011-01-01
The fast growing field of compressed sensing is founded on the fact that if a signal is 'simple' and has some 'structure', then it can be reconstructed accurately with far fewer samples than its ambient dimension. Many different plausible structures have been explored in this field, ranging from sparsity to low-rankness and to finite rate of innovation. However, there are important abstract questions that are yet to be answered. For instance, what are the general abstract meanings of 'structure' and 'simplicity'? Do there exist universal algorithms for recovering such simple structured objects from fewer samples than their ambient dimension? In this paper, we aim to address these two questions. Using algorithmic information theory tools such as Kolmogorov complexity, we provide a unified method of describing 'simplicity' and 'structure'. We then explore the performance of an algorithm motivated by Ocam's Razor (called MCP for minimum complexity pursuit) and show that it requires $O(k\\log n)$ number of samples...
van Zon, A; Mossink, M H; Scheper, R J; Sonneveld, P; Wiemer, E A C
2003-09-01
Vaults are large ribonucleoprotein particles found in eukaryotic cells. They are composed of multiple copies of a Mr 100,000 major vault protein and two minor vault proteins of Mr 193,000 and 240,000, as well as small untranslated RNAs of 86-141 bases. The vault components are arranged into a highly characteristic hollow barrel-like structure of 35 x 65 nm in size. Vaults are predominantly localized in the cytoplasm where they may associate with cytoskeletal elements. A small fraction of vaults are found to be associated with the nucleus. As of yet, the precise cellular function of the vault complex is unknown. However, their distinct morphology and intracellular distribution suggest a role in intracellular transport processes. Here we review the current knowledge on the vault complex, its structure, components and possible functions. PMID:14523546
Fluorido complexes of technetium
Fluorine chemistry has received considerable interest during recent years due to its significant role in the life sciences, especially for drug development. Despite the great nuclear medicinal importance of the radioactive metal technetium in radiopharmaceuticals, its coordination chemistry with the fluorido ligand is by far less explored than that of other ligands. Up to now, only a few technetium fluorides are known. This thesis contains the synthesis, spectroscopic and structural characterization of novel technetium fluorides in the oxidation states ''+1'', ''+2'', ''+4'' and ''+6''. In the oxidation state ''+6'', the fluoridotechnetates were synthesized either from nitridotechnetic(VI) acid or from pertechnetate by using reducing agent and have been isolated as cesium or tetraethylammonium salts. The compounds were characterized spectroscopically and structurally. In the intermediate oxidation state ''+4'', hexafluoridotechnetate(IV) was known for long time and studied spectroscopically. This thesis reports novel and improved syntheses and solved the critical issues of early publications such as the color, some spectroscopic properties and the structure of this key compound. Single crystal analyses of alkali metal, ammonium and tetramethylammonium salts of hexafluoridotechnetate(IV) are presented. In aqueous alkaline solutions, the ammonium salt of hexafluoridotechnetate(IV) undergoes hydrolysis and forms an oxido-bridged dimeric complex. It is the first step hydrolysis product of hexafluoridotechnetate(IV) and was characterized by spectroscopic and crystallographic methods. Low-valent technetium fluorides with the metal in the oxidation states of ''+2'' or ''+1'' are almost unknown. A detailed description of the synthesis and characterization of pentafluoridonitrosyltechnetate(II) is presented. The complex was isolated as alkali metal salts, and spectroscopic as well as structural features of the complexes are presented. Different salts of the trans
This book by Nino Boccara presents a compilation of model systems commonly termed as 'complex'. It starts with a definition of the systems under consideration and how to build up a model to describe the complex dynamics. The subsequent chapters are devoted to various categories of mean-field type models (differential and recurrence equations, chaos) and of agent-based models (cellular automata, networks and power-law distributions). Each chapter is supplemented by a number of exercises and their solutions. The table of contents looks a little arbitrary but the author took the most prominent model systems investigated over the years (and up until now there has been no unified theory covering the various aspects of complex dynamics). The model systems are explained by looking at a number of applications in various fields. The book is written as a textbook for interested students as well as serving as a comprehensive reference for experts. It is an ideal source for topics to be presented in a lecture on dynamics of complex systems. This is the first book on this 'wide' topic and I have long awaited such a book (in fact I planned to write it myself but this is much better than I could ever have written it!). Only section 6 on cellular automata is a little too limited to the author's point of view and one would have expected more about the famous Domany-Kinzel model (and more accurate citation!). In my opinion this is one of the best textbooks published during the last decade and even experts can learn a lot from it. Hopefully there will be an actualization after, say, five years since this field is growing so quickly. The price is too high for students but this, unfortunately, is the normal case today. Nevertheless I think it will be a great success! (book review)
Lindholst, Morten
2015-01-01
Most scholars agree that engaging in preparation and planning is key to a negotiation’s effectiveness but research has largely focused solely on what happens at the negotiation table, rather than in preparation for it. This thesis addresses the balance by clarifying which preparation and planning activities are undertaken to conduct a complex business negotiation. It examines not only what activities are conducted, but also by whom, and when. One important question for both pra...
Complex regimes of synchronization
Yeldesbay, Azamat
2014-01-01
Synchronization is a fundamental phenomenon in nature. It can be considered as a general property of self-sustained oscillators to adjust their rhythm in the presence of an interaction. In this work we investigate complex regimes of synchronization phenomena by means of theoretical analysis, numerical modeling, as well as practical analysis of experimental data. As a subject of our investigation we consider chimera state, where due to spontaneous symmetry-breaking of an initially ho...
Yap, Yee Jiun
2006-01-01
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. Fundamental laws of physics, although successful in explaining many phenomena observed in nature and society, cannot account for the behaviour of complex, non-Hamiltonian systems. Much effort has been devoted to better understanding the topological properties of these systems. Neither ordered nor disordered, these systems of high variability are found in many areas of science. Studies on sand...
Arithmetic of Complex Manifolds
Lange, Herbert
1989-01-01
It was the aim of the Erlangen meeting in May 1988 to bring together number theoretists and algebraic geometers to discuss problems of common interest, such as moduli problems, complex tori, integral points, rationality questions, automorphic forms. In recent years such problems, which are simultaneously of arithmetic and geometric interest, have become increasingly important. This proceedings volume contains 12 original research papers. Its main topics are theta functions, modular forms, abelian varieties and algebraic three-folds.
The Tuberous Sclerosis complex
Smith, M.; Gomez, M.
1993-01-01
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that results from mutations in the TSC1 or TSC2 genes and is associated with hamartoma formation in multiple organ systems. The neurological manifestations of TSC are particularly challenging and include infantile spasms, intractable epilepsy, cognitive disabilities, and autism. Progress over the past 15 years has demonstrated that the TSC1 or TSC2 encoded proteins modulate cell function via the mTOR signaling cascade and serv...
Narayanasamy, Viknashvaran; Wong, Kok Wai; Rai, Shri; Chiou, Andrew
2010-01-01
International audience This paper looks at the game design and engineering approach to model the game design. The game modeling framework discussed in this paper could be a systematic alternative for implementing in the game engine architecture. The suggested game modeling framework incorporates structural game component, temporal game component and boundary game component frameworks. It is suitable to model most complex games and game engines.
Tamke, Martin; Ramsgaard Thomsen, Mette; Riiber Nielsen, Jacob
2009-01-01
The versatility of wood constructions and traditional wood joints for the production of non standard elements was in focus of a design based research. Herein we established a seamless process from digital design to fabrication. A first research phase centered on the development of a robust parame...... parametric model and a generic design language a later explored the possibilities to construct complex shaped geometries with self registering joints on modern wood crafting machines. The research was carried out as collaboration with industrial partners....
ALAN KIRMAN
2004-01-01
This paper presents a view of the economy as a complex system with heterogeneous interacting agents who collectively organize themselves to generate aggregate phenomena which cannot be regarded as the behavior of some average or representative individual. There is an essential difference between the aggregate and the individual and such phenomena as bubbles and crashes, herd behavior, the transmission of information and the organization of trade are better modeled in the sort of framework sug...
2008-01-01
The work presented in this thesis concerns the study of complex nanofluids. The interaction of particles in dispersions under the influence of electric and magnetic fields has been studied. The main focus has been the investigation of the behavior of carbon particle dispersions. A novel type of carbon material, namely carbon cone (CC) material, has been characterized using atomic force microscope, scanning tunnelling microscope and scanning electron microscope. The CC material is a mixed powd...
Complexity Science for Simpletons
Feinstein C. A.
2005-01-01
In this article, we shall describe some of the most interesting topics in the subject of Complexity Science for a general audience. Anyone with a solid foundation in high school mathematics (with some calculus) and an elementary understanding of computer programming will be able to follow this article. First, we shall explain the significance of the P versus NP problem and solve it. Next, we shall describe two other famous mathematics problems, the Collatz 3n+ 1 Conjec...
Complex wounds Feridas complexas
Marcus Castro Ferreira; Paulo Tuma Júnior; Viviane Fernandes de Carvalho; Fábio Kamamoto
2006-01-01
Complex wound is the term used more recently to group those well-known difficult wounds, either chronic or acute, that challenge medical and nursing teams. They defy cure using conventional and simple "dressings" therapy and currently have a major socioeconomic impact. The purpose of this review is to bring these wounds to the attention of the health-care community, suggesting that they should be treated by multidisciplinary teams in specialized hospital centers. In most cases, surgical treat...
Muhammad Talha Khan; Rose Amy Franco
2014-01-01
Complex sleep apnea is the term used to describe a form of sleep disordered breathing in which repeated central apneas (>5/hour) persist or emerge when obstructive events are extinguished with positive airway pressure (PAP) and for which there is not a clear cause for the central apneas such as narcotics or systolic heart failure. The driving forces in the pathophysiology are felt to be ventilator instability associated oscillation in PaCO2 arterial partial pressure of Carbon Dioxide, continu...
Poenaru, D N; Greiner, W
2005-01-01
Complex fission phenomena can be studied in a unified way. Very general reflection asymmetrical equilibrium (saddle-point) nuclear shapes, may be obtained by solving an integro-differential equation without being necessary to specify a certain parametrization. The mass asymmetry in cold fission phenomena can be explained as the result of adding a phenomenological shell correction to the liquid drop model deformation energy. Applications to binary, ternary, and quaternary fission are outlined. Predictions of two alpha accompanied fission are experimentally confirmed.
Irreducible symplectic complex spaces
Kirschner, Tim
2012-01-01
In chapter 1 we define period mappings of Hodge-de Rahm type for certain submersive, yet not necessarily locally topologically trivial, morphisms of complex manifolds. Generalizing Griffiths's theory, we interpret the differential of such period mappings as the composition of the Kodaira-Spencer map and a map derived from the sheaf cohomological cup product and the contraction of vector fields with differential forms. In chapter 2 of the text, we consider a submersive morphism $f\\colon X\\to S...
Poenaru, Dorin N.; Gherghescu, Radu A.; Greiner, Walter
2005-01-01
Complex fission phenomena are studied in a unified way. Very general reflection asymmetrical equilibrium (saddle point) nuclear shapes are obtained by solving an integro-differential equation without being necessary to specify a certain parametrization. The mass asymmetry in binary cold fission of Th and U isotopes is explained as the result of adding a phenomenological shell correction to the liquid drop model deformation energy. Applications to binary, ternary, and quaternary fission are ou...
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...
Complexity, contingency, and criticality.
Bak, P; M. Paczuski
1995-01-01
Complexity originates from the tendency of large dynamical systems to organize themselves into a critical state, with avalanches or "punctuations" of all sizes. In the critical state, events which would otherwise be uncoupled become correlated. The apparent, historical contingency in many sciences, including geology, biology, and economics, finds a natural interpretation as a self-organized critical phenomenon. These ideas are discussed in the context of simple mathematical models of sandpile...
Complex regional pain syndrome.
Bruehl, Stephen
2015-01-01
Complex regional pain syndrome is a chronic pain condition characterized by autonomic and inflammatory features. It occurs acutely in about 7% of patients who have limb fractures, limb surgery, or other injuries. Many cases resolve within the first year, with a smaller subset progressing to the chronic form. This transition is often paralleled by a change from "warm complex regional pain syndrome," with inflammatory characteristics dominant, to "cold complex regional pain syndrome" in which autonomic features dominate. Multiple peripheral and central mechanisms seem to be involved, the relative contributions of which may differ between individuals and over time. Possible contributors include peripheral and central sensitization, autonomic changes and sympatho-afferent coupling, inflammatory and immune alterations, brain changes, and genetic and psychological factors. The syndrome is diagnosed purely on the basis of clinical signs and symptoms. Effective management of the chronic form of the syndrome is often challenging. Few high quality randomized controlled trials are available to support the efficacy of the most commonly used interventions. Reviews of available randomized trials suggest that physical and occupational therapy (including graded motor imagery and mirror therapy), bisphosphonates, calcitonin, subanesthetic intravenous ketamine, free radical scavengers, oral corticosteroids, and spinal cord stimulation may be effective treatments. Multidisciplinary clinical care, which centers around functionally focused therapies is recommended. Other interventions are used to facilitate engagement in functional therapies and to improve quality of life. PMID:26224572
Albertos, Pedro; Blanke, Mogens; Isidori, Alberto; Schaufelberger, Walter; Sanz, Ricardo
2001-01-01
The world of artificial systems is reaching complexity levels that es cape human understanding. Surface traffic, electricity distribution, air planes, mobile communications, etc. , are examples that demonstrate that we are running into problems that are beyond classical scientific or engi neering knowledge. There is an ongoing world-wide effort to understand these systems and develop models that can capture its behavior. The reason for this work is clear, if our lack of understanding deepens, we will lose our capability to control these systems and make they behave as we want. Researchers from many different fields are trying to understand and develop theories for complex man-made systems. This book presents re search from the perspective of control and systems theory. The book has grown out of activities in the research program Control of Complex Systems (COSY). The program has been sponsored by the Eu ropean Science Foundation (ESF) which for 25 years has been one of the leading players in stimula...
Ormerod, Paul
In the spirit of the overall topic of the conference, in this paper I consider the extent to which economic theory includes elements of the complex systems approach. I am setting to one side here the developments over the past decade in applying complex systems analysis to economic problems. This is not because this recent work is not important. It most certainly is. But I want to argue that there is a very distinct tradition of what we would now describe as a complex systems approach in the works of two of the greatest economists of the 20th century. There is of course a dominant intellectual paradigm within economics, that known as `neo-classical'economics. This paradigm is by no means an empty box, and is undoubtedly useful in helping to understand how some aspects of the social and economic worlds work. But even in its heyday, neo-classical economics never succeeded by its empirical success in driving out completely other theoretical approaches, for its success was simply not sufficient to do so. Much more importantly, economics over the past twenty or thirty years has become in an increasing state of flux.
Software Complexity Methodologies & Software Security
Masoud Rafighi; Nasser Modiri
2011-01-01
It is broadly clear that complexity is one of the software natural features. Software natural complexity and software requirement functionality are two inseparable part and they have special range. measurement complexity have explained with using the MacCabe and Halsted models and with an example discuss about software complexity in this paper Flow metric information Henry and Kafura, complexity metric system Agresti-card-glass, design metric in item’s level have compared and peruse then cate...
Transition Complexity of Incomplete DFAs
Yuan Gao; Kai Salomaa; Sheng Yu
2010-01-01
In this paper, we consider the transition complexity of regular languages based on the incomplete deterministic finite automata. A number of results on Boolean operations have been obtained. It is shown that the transition complexity results for union and complementation are very different from the state complexity results for the same operations. However, for intersection, the transition complexity result is similar to that of state complexity.
Sensemaking: a complexity perspective
Timothy Lynam
2015-03-01
Full Text Available Our intent was to provide a methodological overview of the primary data collection process in support of the other articles in this special issue. We documented and illustrated the use of a data collection and analysis suite, SenseMaker, that was designed to collect and work with narrative fragments. The approach presented adds a new and inherently mixed tool to the mixed methods toolbox. Despite its novelty and potential utility, little has been written in the academic literature on the application of SenseMaker to complex problems. To the best of our knowledge, the approach has not been used in relation to climate change or climate change adaptation and has not been presented in the mixed methods literature. We sought to contribute to filling this gap through describing the approach used to generate the data that underpin the articles in this special feature. Our purpose was to illustrate some of the potential and most notable challenges of using the SenseMaker data collection and analysis process in a complex domain through examining adaptation to climate change. Our overview was not exhaustive but rather sought to highlight capabilities and challenges through examining experiences of adaptation from a stages of change perspective. SenseMaker provides a remarkably powerful tool for the capture of micronarratives of complex phenomena such as climate change. The capacity to have respondents interpret, i.e., make sense of, their own narratives is an important innovation that provides one plausible solution to the problem of analysts coding narratives. Analytically, however, SenseMaker is relatively weak for those seeking strong statistical support for analyses and provides no capability for analyzing the narratives themselves.
Baldi, Pierre; Lu, Zhiqin
2012-01-01
Autoencoders are unsupervised machine learning circuits, with typically one hidden layer, whose learning goal is to minimize an average distortion measure between inputs and outputs. Linear autoencoders correspond to the special case where only linear transformations between visible and hidden variables are used. While linear autoencoders can be defined over any field, only real-valued linear autoencoders have been studied so far. Here we study complex-valued linear autoencoders where the components of the training vectors and adjustable matrices are defined over the complex field with the L2 norm. We provide simpler and more general proofs that unify the real-valued and complex-valued cases, showing that in both cases the landscape of the error function is invariant under certain groups of transformations. The landscape has no local minima, a family of global minima associated with Principal Component Analysis, and many families of saddle points associated with orthogonal projections onto sub-space spanned by sub-optimal subsets of eigenvectors of the covariance matrix. The theory yields several iterative, convergent, learning algorithms, a clear understanding of the generalization properties of the trained autoencoders, and can equally be applied to the hetero-associative case when external targets are provided. Partial results on deep architecture as well as the differential geometry of autoencoders are also presented. The general framework described here is useful to classify autoencoders and identify general properties that ought to be investigated for each class, illuminating some of the connections between autoencoders, unsupervised learning, clustering, Hebbian learning, and information theory. PMID:22622264
Ayres, Phil
2006-01-01
raised by the statements above. The forest territory is a vast managed landscape exhibiting a multiplicity of conditions in constant flux resulting from the management strategy of the 50 year cycle – a period defining the planting, maturation and harvesting of each forest plot. The cognitive psychologist......, specificity and complexity. By considering the design process as a continual iterative cycle in which the digital and analogue are closely coupled, we might imagine a construct that continually redefines itself in relation to its context, attempting to become increasingly specific to location and purpose over...
Organization of complex networks
Kitsak, Maksim
Many large complex systems can be successfully analyzed using the language of graphs and networks. Interactions between the objects in a network are treated as links connecting nodes. This approach to understanding the structure of networks is an important step toward understanding the way corresponding complex systems function. Using the tools of statistical physics, we analyze the structure of networks as they are found in complex systems such as the Internet, the World Wide Web, and numerous industrial and social networks. In the first chapter we apply the concept of self-similarity to the study of transport properties in complex networks. Self-similar or fractal networks, unlike non-fractal networks, exhibit similarity on a range of scales. We find that these fractal networks have transport properties that differ from those of non-fractal networks. In non-fractal networks, transport flows primarily through the hubs. In fractal networks, the self-similar structure requires any transport to also flow through nodes that have only a few connections. We also study, in models and in real networks, the crossover from fractal to non-fractal networks that occurs when a small number of random interactions are added by means of scaling techniques. In the second chapter we use k-core techniques to study dynamic processes in networks. The k-core of a network is the network's largest component that, within itself, exhibits all nodes with at least k connections. We use this k-core analysis to estimate the relative leadership positions of firms in the Life Science (LS) and Information and Communication Technology (ICT) sectors of industry. We study the differences in the k-core structure between the LS and the ICT sectors. We find that the lead segment (highest k-core) of the LS sector, unlike that of the ICT sector, is remarkably stable over time: once a particular firm enters the lead segment, it is likely to remain there for many years. In the third chapter we study how
Languages, decidability, and complexity
Haar, S.; Masopust, Tomáš
1. London: Springer, 2013 - (Seatzu, C.; Silva, M.; van Schuppen, J.), s. 23-43. (Lecture Notes in Control and Information Sciences. 433). ISBN 978-1-4471-4275-1 R&D Projects: GA ČR GPP202/11/P028 Grant ostatní: European Commission(XE) EU. ICT .DISC 224498 Institutional support: RVO:67985840 Keywords : Automata theory * decidability * complexity Subject RIV: BA - General Mathematics http://link.springer.com/chapter/10.1007/978-1-4471-4276-8_2
Ventricular premature complexes
Bockeria O.L.
2015-06-01
Full Text Available Ventricular premature complexes are fairly common heart rhythm disturbances. They occur in patients of all age groups. Sometimes the registration of electrocardiogram is ample for the diagnosis.The difficulty lies in determining the causes of ventricular arrhythmia. The detailed examination is needed for verification of the diagnosis and risk stratification: a Holter monitoring, laboratory tests, a heart magnetic resonance imaging, an electrophysiological study. This results can significantly change further tactics of patient management.It is necessary to make a deliberate decision in favor of one or another treatment after revealing the causes.
Sodha, Mahendra Singh
2014-01-01
The presentation in the book is based on charge balance on the dust particles, number and energy balance of the constituents and atom-ion-electron interaction in the gaseous plasma. Size distribution of dust particles, statistical mechanics, Quantum effects in electron emission from and accretion on dust particles and nonlinear interaction of complex plasmas with electric and electromagnetic fields have been discussed in the book. The book introduces the reader to basic concepts and typical applications. The book should be of use to researchers, engineers and graduate students.
STUDYING COMPLEX ADAPTIVE SYSTEMS
John H. Holland
2006-01-01
Complex adaptive systems (cas) - systems that involve many components that adapt or learn as they interact - are at the heart of important contemporary problems. The study of cas poses unique challenges: Some of our most powerful mathematical tools, particularly methods involving fixed points, attractors, and the like, are of limited help in understanding the development of cas. This paper suggests ways to modify research methods and tools, with an emphasis on the role of computer-based models, to increase our understanding of cas.
2007-01-01
The vast majority of gold complexes with five group-element donor ligands contain tertiary phosphines, although compounds with amine, arsine or stibine ligands are also known. Although phosphide ligands, which are formed by deprotonation of non-tertiary phosphines, are closely related to the former, they have been employed to a lesser extent, mainly due to their lower stability. Thus, the chemistry of phosphido-bridged derivatives of the main group elements1-3 or transition metals4-6 has been...
Computability, complexity, logic
Börger, Egon
1989-01-01
The theme of this book is formed by a pair of concepts: the concept of formal language as carrier of the precise expression of meaning, facts and problems, and the concept of algorithm or calculus, i.e. a formally operating procedure for the solution of precisely described questions and problems. The book is a unified introduction to the modern theory of these concepts, to the way in which they developed first in mathematical logic and computability theory and later in automata theory, and to the theory of formal languages and complexity theory. Apart from considering the fundamental themes an
Complex regional pain syndrome
Sandeep J Sebastin
2011-01-01
Full Text Available Complex regional pain syndrome (CRPS previously known as reflex sympathetic dystrophy is a chronic neurological disorder involving the limbs characterized by disabling pain, swelling, vasomotor instability, sudomotor abnormality, and impairment of motor function. CRPS is not uncommon after hand surgery and may complicate post-operative care. There is no specific diagnostic test for CRPS and the diagnosis is based on history, clinical examination, and supportive laboratory findings. Recent modifications to diagnostic criteria have enabled clinicians to diagnose this disease more consistently. This review gives a synopsis of CRPS and discusses the diagnosis, pathophysiology, and treatment options based on the limited evidence in the literature.
Mellerup, Erling; Møller, Gert Lykke; Koefoed, Pernille
2012-01-01
A complex disease with an inheritable component is polygenic, meaning that several different changes in DNA are the genetic basis for the disease. Such a disease may also be genetically heterogeneous, meaning that independent changes in DNA, i.e. various genotypes, can be the genetic basis...... for the disease. Each of these genotypes may be characterized by specific combinations of key genetic changes. It is suggested that even if all key changes are found in genes related to the biology of a certain disease, the number of combinations may be so large that the number of different genotypes may be close...
Hartmann, A.; Roehrich, J.; Frederiksen, Lars;
2014-01-01
transition process. Design/methodology/approach – A multiple, longitudinal case study method is used to examine the transition towards PCP. The study deploys rich qualitative data sets by combining semi-structured interviews, focus group meetings and organisational reports and documents. Findings – The...... contractual and relational challenges they need to master when facing higher levels of performance and infrastructural complexity. Originality/value – The study adds to the limited empirical and conceptual understanding on the nature of long-term public-private interactions in PCP. It contributes through a...
Fluorido complexes of technetium
Mariappan Balasekaran, Samundeeswari
2013-07-04
Fluorine chemistry has received considerable interest during recent years due to its significant role in the life sciences, especially for drug development. Despite the great nuclear medicinal importance of the radioactive metal technetium in radiopharmaceuticals, its coordination chemistry with the fluorido ligand is by far less explored than that of other ligands. Up to now, only a few technetium fluorides are known. This thesis contains the synthesis, spectroscopic and structural characterization of novel technetium fluorides in the oxidation states ''+1'', ''+2'', ''+4'' and ''+6''. In the oxidation state ''+6'', the fluoridotechnetates were synthesized either from nitridotechnetic(VI) acid or from pertechnetate by using reducing agent and have been isolated as cesium or tetraethylammonium salts. The compounds were characterized spectroscopically and structurally. In the intermediate oxidation state ''+4'', hexafluoridotechnetate(IV) was known for long time and studied spectroscopically. This thesis reports novel and improved syntheses and solved the critical issues of early publications such as the color, some spectroscopic properties and the structure of this key compound. Single crystal analyses of alkali metal, ammonium and tetramethylammonium salts of hexafluoridotechnetate(IV) are presented. In aqueous alkaline solutions, the ammonium salt of hexafluoridotechnetate(IV) undergoes hydrolysis and forms an oxido-bridged dimeric complex. It is the first step hydrolysis product of hexafluoridotechnetate(IV) and was characterized by spectroscopic and crystallographic methods. Low-valent technetium fluorides with the metal in the oxidation states of ''+2'' or ''+1'' are almost unknown. A detailed description of the synthesis and characterization of pentafluoridonitrosyltechnetate(II) is presented. The
Characterizing biomaterial complexity
L.A. Clifton
2009-07-01
Full Text Available Biomaterials research will always require a range of techniques to examine structure and function on a range of length scales and in a range of settings. Neutron scattering provides a unique way of disentangling the molecular and structural complexity of biomaterials through study of the constituent components. We examine how the technique has been used to study surface immobilized proteins and lipid films, floating lipid bilayers as mimics of in vitro planar membranes, and formation of fibres from solution by insects and spiders.
Polyhydride complexes for hydrogen storage
Jensen, C.M. [Univ. of Hawaii, Honolulu, HI (United States)
1995-09-01
Polyhydride metal complexes are being developed for application in hydrogen storage. Efforts have focused on developing complexes with improved available hydrogen weight percentages. We have explored the possibility that complexes containing aromatic hydrocarbon ligands could store hydrogen at both the metal center and in the ligands. We have synthesized novel indenyl hydride complexes and explored their reactivity with hydrogen. The reversible hydrogenation of [IrH{sub 3}(PPh{sub 3})({eta}{sup 5}-C{sub 10}H{sub 7})]{sup +} has been achieved. While attempting to prepare {eta}{sup 6}-tetrahydronaphthalene complexes, we discovered that certain polyhydride complexes catalyze both the hydrogenation and dehydrogenation of tetrahydronaphthalene.
Canonical metrics on complex manifold
YAU Shing-Tung
2008-01-01
@@ Complex manifolds are topological spaces that are covered by coordinate charts where the Coordinate changes are given by holomorphic transformations. For example, Riemann surfaces are one dimensional complex manifolds. In order to understand complex manifolds, it is useful to introduce metrics that are compatible with the complex structure. In general, we should have a pair (M, ds2M) where ds2M is the metric. The metric is said to be canonical if any biholomorphisms of the complex manifolds are automatically isometries. Such metrics can naturally be used to describe invariants of the complex structures of the manifold.
Canonical metrics on complex manifold
YAU; Shing-Tung(Yau; S.-T.)
2008-01-01
Complex manifolds are topological spaces that are covered by coordinate charts where the coordinate changes are given by holomorphic transformations.For example,Riemann surfaces are one dimensional complex manifolds.In order to understand complex manifolds,it is useful to introduce metrics that are compatible with the complex structure.In general,we should have a pair(M,ds~2_M)where ds~2_M is the metric.The metric is said to be canonical if any biholomorphisms of the complex manifolds are automatically isometries.Such metrics can naturally be used to describe invariants of the complex structures of the manifold.
Shapes of interacting RNA complexes
Fu, Benjamin Mingming; Reidys, Christian
2014-01-01
Shapes of interacting RNA complexes are studied using a filtration via their topological genus. A shape of an RNA complex is obtained by (iteratively) collapsing stacks and eliminating hairpin loops.This shape-projection preserves the topological core of the RNA complex and for fixed topological...... genus there are only finitely many such shapes. Our main result is a new bijection that relates the shapes of RNA complexes with shapes of RNA structures. This allows to compute the shape polynomial of RNA complexes via the shape polynomial of RNA structures. We furthermore present a linear time uniform...... sampling algorithm for shapes of RNA complexes of fixed topological genus....
Complex dynamical invariants for two-dimensional complex potentials
J S Virdi; F Chand; C N Kumar; S C Mishra
2012-08-01
Complex dynamical invariants are searched out for two-dimensional complex potentials using rationalization method within the framework of an extended complex phase space characterized by $x = x_{1} + ip_{3}. y = x_{2} + ip_{4}, p_{x} = p_{1} + ix_{3}, p_{y} = p_{2} + ix_{4}$. It is found that the cubic oscillator and shifted harmonic oscillator admit quadratic complex invariants. THe obtained invariants may be useful for studying non-Hermitian Hamiltonian systems.
Theoretical research progress in complexity of complex dynamical networks
Fang Jinqing
2007-01-01
This article reviews the main progress in dynamical complexity of theoretical models for nonlinear complex networks proposed by our Joint Complex Network Research Group (JCNRG). The topological and dynamical properties of these theoretical models are numerically and analytically studied. Several findings are useful for understanding and deeply studying complex networks from macroscopic to microscopic levels and have a potential of applications in real-world networks.
Stehr, N; Grundmann, R
2001-06-01
The assertion about the unique 'complexity' or the peculiarly intricate character of social phenomena has, at least within sociology, a long, venerable and virtually uncontested tradition. At the turn of the last century, classical social theorists, for example, Georg Simmel and Emile Durkheim, made prominent and repeated reference to this attribute of the subject matter of sociology and the degree to which it complicates, even inhibits the develop and application of social scientific knowledge. Our paper explores the origins, the basis and the consequences of this assertion and asks in particular whether the classic complexity assertion still deserves to be invoked in analyses that ask about the production and the utilization of social scientific knowledge in modern society. We present John Maynard Keynes' economic theory and its practical applications as an illustration. We conclude that the practical value of social scientific knowledge is not dependent on a faithful, in the sense of complete, representation of social reality. Instead, social scientific knowledge that wants to optimize its practicality has to attend and attach itself to elements of social situations that can be altered or are actionable. PMID:11440059
Organometallic Complexes of Graphene
Sarkar, Santanu; Bekyarova, Elena; Haddon, Robert C
2013-01-01
We demonstrate the organometallic hexahapto complexation of chromium with graphene, graphite and carbon nanotubes. All of these extended periodic pi-electron systems exhibit some degree of reactivity toward the reagents CrCO)6 and (eta6-benzene)Cr(CO)3, and we are able to demonstrate the formation of (eta6-rene)Cr(CO)3 or (eta6-arene)2Cr, where arene = single-walled carbon nanotubes (SWNT), exfoliated graphene (XG), epitaxial graphene (EG) and highly-oriented pyrolytic graphite (HOPG). We find that the SWNTs are the least reactive presumably as a result of the effect of curvature on the formation of the hexahapto bond; in the case of HOPG, (eta6-HOPG)Cr(CO)3 was isolated while the exfoliated graphene samples were found to give both (eta6-graphene)2Cr, and (eta6-graphene)Cr(CO)3 structures. We report simple and efficient routes for the mild decomplexation of the graphene-chromium complexes which appears to restore the original pristine graphene state. This study represents the first example of the use of graph...
Henske, Elizabeth P; Jóźwiak, Sergiusz; Kingswood, J Christopher; Sampson, Julian R; Thiele, Elizabeth A
2016-01-01
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems and is caused by loss-of-function mutations in one of two genes: TSC1 or TSC2. The disorder can affect both adults and children. First described in depth by Bourneville in 1880, it is now estimated that nearly 2 million people are affected by the disease worldwide. The clinical features of TSC are distinctive and can vary widely between individuals, even within one family. Major features of the disease include tumours of the brain, skin, heart, lungs and kidneys, seizures and TSC-associated neuropsychiatric disorders, which can include autism spectrum disorder and cognitive disability. TSC1 (also known as hamartin) and TSC2 (also known as tuberin) form the TSC protein complex that acts as an inhibitor of the mechanistic target of rapamycin (mTOR) signalling pathway, which in turn plays a pivotal part in regulating cell growth, proliferation, autophagy and protein and lipid synthesis. Remarkable progress in basic and translational research, in addition to several randomized controlled trials worldwide, has led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas and pulmonary lymphangioleiomyomatosis, but further research is needed to establish full indications of therapeutic treatment. In this Primer, we review the state-of-the-art knowledge in the TSC field, including the molecular and cellular basis of the disease, medical management, major knowledge gaps and ongoing research towards a cure. PMID:27226234