Zymosan-induced immune challenge modifies the stress response of hypoxic air-breathing fish (Anabas testudineus Bloch): Evidence for reversed patterns of cortisol and thyroid hormone interaction, differential ion transporter functions and non-specific immune response.

Science.gov (United States)

Simi, S; Peter, Valsa S; Peter, M C Subhash

2017-09-15

Fishes have evolved physiological mechanisms to exhibit stress response, where hormonal signals interact with an array of ion transporters and regulate homeostasis. As major ion transport regulators in fish, cortisol and thyroid hormones have been shown to interact and fine-tune the stress response. Likewise, in fishes many interactions have been identified between stress and immune components, but the physiological basis of such interaction has not yet delineated particularly in air-breathing fish. We, therefore, investigated the responses of thyroid hormones and cortisol, ion transporter functions and non-specific immune response of an obligate air-breathing fish Anabas testudineus Bloch to zymosan treatment or hypoxia stress or both, to understand how immune challenge modifies the pattern of stress response in this fish. Induction of experimental peritonitis in these fish by zymosan treatment (200ngg -1 ) for 24h produced rise in respiratory burst and lysozomal activities in head kidney phagocytes. In contrast, hypoxia stress for 30min in immune-challenged fish reversed these non-specific responses of head kidney phagocytes. The decline in plasma cortisol in zymosan-treated fish and its further suppression by hypoxia stress indicate that immune challenge suppresses the cortisol-driven stress response of this fish. Likewise, the decline in plasma T 3 and T 4 after zymosan-treatment and the rise in plasma T 4 after hypoxia stress in immune-challenged fish indicate a critical role for thyroid hormone in immune-stress response due to its differential sensitivity to both immune and stress challenges. Further, analysis of the activity pattern of ion-dependent ATPases viz. Na + /K + -ATPase, H + /K + -ATPase and Na + /NH 4 + -ATPase indicates a functional interaction of ion transport system with the immune response as evident in its differential and spatial modifications after hypoxia stress in immune-challenged fish. The immune-challenge that produced differential

Biochemical effects of glyphosate based herbicide, Excel Mera 71 on enzyme activities of acetylcholinesterase (AChE), lipid peroxidation (LPO), catalase (CAT), glutathione-S-transferase (GST) and protein content on teleostean fishes.

Science.gov (United States)

Samanta, Palas; Pal, Sandipan; Mukherjee, Aloke Kumar; Ghosh, Apurba Ratan

2014-09-01

Effects of glyphosate based herbicide, Excel Mera 71 at a dose of 17.20mg/l on enzyme activities of acetylcholinesterase (AChE), lipid peroxidation (LPO), catalase (CAT), glutathione-S-transferase (GST) and protein content were measured in different tissues of two Indian air-breathing teleosts, Anabas testudineus (Bloch) and Heteropneustes fossilis (Bloch) during an exposure period of 30 days under laboratory condition. AChE activity was significantly increased in all the investigated tissues of both fish species and maximum elevation was observed in brain of H. fossilis, while spinal cord of A. testudineus showed minimum increment. Fishes showed significant increase LPO levels in all the tissues; highest was observed in gill of A. testudineus but lowest LPO level was observed in muscle of H. fossilis. CAT was also enhanced in both the fishes, while GST activity in liver diminished substantially and minimum was observed in liver of A. testudineus. Total protein content showed decreased value in all the tissues, maximum reduction was observed in liver and minimum in brain of A. testudineus and H. fossilis respectively. The results indicated that Excel Mera 71 caused serious alterations in the enzyme activities resulting into severe deterioration of fish health; so, AChE, LPO, CAT and GST can be used as suitable indicators of herbicidal toxicity. Copyright © 2014 Elsevier Inc. All rights reserved.

Evaluation of metabolic enzymes in response to Excel Mera 71, a glyphosate-based herbicide, and recovery pattern in freshwater teleostean fishes.

Science.gov (United States)

Samanta, Palas; Pal, Sandipan; Mukherjee, Aloke Kumar; Ghosh, Apurba Ratan

2014-01-01

Metabolic enzymes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were evaluated in Indian teleostean fishes, namely, Anabas testudineus (Bloch) and Heteropneustes fossilis (Bloch), for an exposure to 30 days of Excel Mera 71 (17.2 mg/L), a glyphosate formulation, and subsequent depuration under Liv.52, a plant extract at a dose of 187.5 mg/d/250 L for the same period in the same tissues under laboratory condition. ALT activity was significantly increased (PExcel Mera 71 caused alterations in the metabolic enzymatic activities in fish tissues and AST showed the highest alteration in both the fishes, while lowest in ALP and ALT in A. testudineus and H. fossilis, respectively. During depuration under Liv.52, all the enzyme activities came down towards the control condition which indicated the compensatory response by the fish against this herbicidal stress and it was in the following order: AST>ALT>ALP, in A. testudineus, while H. fossilis showed the following trend: ALT>AST>ALP. Therefore, these parameters could be used as indicators of herbicidal pollution in aquatic organisms and were recommended for environmental monitoring for investigating the mechanism involved in the recovery pattern.

Increases in apoptosis, caspase activity and expression of p53 and bax, and the transition between two types of mitochondrion-rich cells, in the gills of the climbing perch, Anabas testudineus, during a progressive acclimation from freshwater to seawater

Science.gov (United States)

Ching, Biyun; Chen, Xiu L.; Yong, Jing H. A.; Wilson, Jonathan M.; Hiong, Kum C.; Sim, Eugene W. L.; Wong, Wai P.; Lam, Siew H.; Chew, Shit F.; Ip, Yuen K.

2013-01-01

This study aimed to test the hypothesis that branchial osmoregulatory acclimation involved increased apoptosis and replacement of mitochdonrion-rich cells (MRCs) in the climbing perch, Anabas testudineus, during a progressive acclimation from freshwater to seawater. A significant increase in branchial caspase-3/-7 activity was observed on day 4 (salinity 20), and an extensive TUNEL-positive apoptosis was detected on day 5 (salinity 25), indicating salinity-induced apoptosis had occurred. This was further supported by an up-regulation of branchial mRNA expression of p53, a key regulator of cell cycle arrest and apoptosis, between day 2 (salinity 10) and day 6 (seawater), and an increase in branchial p53 protein abundance on day 6. Seawater acclimation apparently activated both the extrinsic and intrinsic pathways, as reflected by significant increases in branchial caspase-8 and caspase-9 activities. The involvement of the intrinsic pathway was confirmed by the significant increase in branchial mRNA expression of bax between day 4 (salinity 20) and day 6 (seawater). Western blotting results revealed the presence of a freshwater Na+/K+-ATPase (Nka) α-isoform, Nka α1a, and a seawater isoform, Nka α1b, the protein abundance of which decreased and increased, respectively, during seawater acclimation. Immunofluorescence microscopy revealed the presence of two types of MRCs distinctly different in sizes, and confirmed that the reduction in Nka α1a expression, and the prominent increases in expression of Nka α1b, Na+:K+:2Cl− cotransporter 1, and cystic fibrosis transmembrane conductance regulator Cl− channel coincided with the salinity-induced apoptotic event. Since modulation of existing MRCs alone could not have led to extensive salinity-induced apoptosis, it is probable that some, if not all, freshwater-type MRCs could have been removed through increased apoptosis and subsequently replaced by seawater-type MRCs in the gills of A. testudineus during seawater

Dicty_cDB: Contig-U15667-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 80732 |pid:none) Anabas testudineus cyclin B mRNA, ... 50 3e-04 AF086634_1( AF086...B... 50 3e-04 AM920436_191( AM920436 |pid:none) Penicillium chrysogenum Wisconsi... 50 3e-04 EU780732_1( EU7

Dicty_cDB: Contig-U09533-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 33308 |pid:none) Anabas testudineus cyclin-dependen... 253 1e-65 BC061617_1( BC06..... 253 1e-65 EU006765_1( EU006765 |pid:none) Gossypium hirsutum cultivar des119... 253 1e-65 AY533308_1( AY5

A study on some enzymes in rice field fish as biomarkers for pesticide exposure

International Nuclear Information System (INIS)

Juzu Hayati Arshad; Mazlina Muhammad; Salmijah Surif; Abdul Manan Mat Jais

2002-01-01

A study was carried out on three enzymes in rice field fish which can be used as possible biomarkers for pesticide exposure. The results obtained showed that the activity of the enzyme EROD (ethoxyresorufin-o-deethylase) increased between 1.5-2.2 fold in snakehead or haruan (Channa striata) sampled from the pesticide polluted areas, particularly the recycled areas and only a slight increase in EROD activity in climbing perch or puyu (Anabas testudineus). Increase in the activity of carboxylesterase was also noted. The percentage inhibition of acety1cholinesterase ranges from 18.4%-57.4% and 2.5%-34.2% for Channa striata and Anabas testudineus, respectively. Generally, a higher percentage of acety1cholinesterase inhibition was noted for those fish sampled from the recycled areas. The noted changes in the activity of these enzymes suggest exposure of rice field fish to foreign compounds, possibly pesticides, which are known to induce EROD activity and inhibit acety1cholinesterase activity. Therefore it may be possible to use these enzymes as biomarkers for pesticide exposure. (Author)

Na+/H+ Exchanger 3 Is Expressed in Two Distinct Types of Ionocyte, and Probably Augments Ammonia Excretion in One of Them, in the Gills of the Climbing Perch Exposed to Seawater

Directory of Open Access Journals (Sweden)

Xiu L. Chen

2017-11-01

Full Text Available The freshwater climbing perch, Anabas testudineus, is an euryhaline teleost and an obligate air-breather with the ability to actively excrete ammonia. Members of the Na+/H+ exchanger (NHE family help maintain intracellular pH homeostasis and ionic balance through the electroneutral exchange of Na+ and H+. This study aimed to obtain, from the gills of A. testudineus, the full cDNA coding sequence of nhe3, and to determine the effects of exposure to seawater or 100 mmol l−1 of NH4Cl in fresh water on its mRNA and protein expression levels. Efforts were also made to elucidate the type of ionocyte that Nhe3 was associated with in the branchial epithelium of A. testudineus. The transcript level and protein abundance of nhe3/Nhe3 were very low in the gills of freshwater A. testudineus, but they increased significantly in the gills of fish acclimated to seawater. In the gills of fish exposed to seawater, Nhe3 was expressed in two distinct types of seawater-inducible Na+/K+-ATPase (Nka-immunoreactive ionocytes. In Nkaα1b-immunoreactive ionocytes, Nhe3 had an apical localization. As these ionocytes also expressed apical Rhcg1 and basolateral Rhcg2, which are known to transport ammonia, they probably participated in proton-facilitated ammonia excretion in A. testudineus during seawater acclimation. In Nkaα1c-immunoreactive ionocytes, Nhe3 was atypically expressed in the basolateral membrane, and its physiological function is uncertain. For A. testudineus exposed to NH4Cl in fresh water, the transcript and protein expression levels of nhe3/Nhe3 remained low. In conclusion, the branchial Nhe3 of A. testudineus plays a greater physiological role in passive ammonia transport and acid-base balance during seawater acclimation than in active ammonia excretion during environmental ammonia exposure.

A theory of generalized Bloch oscillations

International Nuclear Information System (INIS)

Duggen, Lars; Lassen, Benny; Lew Yan Voon, L C; Willatzen, Morten

2016-01-01

Bloch oscillations of electrons are shown to occur for cases when the energy spectrum does not consist of the traditional evenly-spaced ladders and the potential gradient does not result from an external electric field. A theory of such generalized Bloch oscillations is presented and an exact calculation is given to confirm this phenomenon. Our results allow for a greater freedom of design for experimentally observing Bloch oscillations. For strongly coupled oscillator systems displaying Bloch oscillations, it is further demonstrated that reordering of oscillators leads to destruction of Bloch oscillations. We stipulate that the presented theory of generalized Bloch oscillations can be extended to other systems such as acoustics and photonics. (paper)

Experimental infection of Aphanomyces invadans and susceptibility in seven species of tropical fish

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Seyedeh F. Afzali

2015-09-01

Full Text Available Aim: Epizootic ulcerative syndrome (EUS causes by aquatic oomycete fungus, Aphanomyces invadans is a dangerous fish disease of a wide range of fresh and brackish water, wild and farmed fish throughout the world. The objective of the present study was to determine the susceptibility of a number of tropical fish species to the EUS and compare the severity of infection between experimental groups. Materials and Methods: Snakehead, Channa striata (Bloch, 1793; snakeskin gourami, Trichopodus pectoralis (Regan, 1910; koi carp, Cyprinus carpio (Linnaeus, 1758; broadhead catfish, Clarias macrocephalus (Günther, 1864; goldfish, Carassius auratus (Linnaeus, 1758; climbing perch, Anabas testudineus (Bloch, 1792; and Nile tilapia, Oreochromis niloticus (Linnaeus, 1758 were challenged by intramuscular injection using zoospores of Aphanomyces invadans (NJM9701. The infected fish skins and muscles were examined for EUS histopathological characteristics, and the results on the severity of lesions and mortality were analyzed using SPSS program. Results: All zoospore-injected fish were shown to be susceptible to the EUS infection except Nile tilapia. Although, the general histopathological pattern was similar in the zoospore-injected group, but there were some variation in granulomatous reaction, that is the presence or absence of giant cells, and time of mortality were detected. The result of statistical analysis showed that there was a significant difference between species, (c2=145.11 and p<0.01. Conclusion: Gourami, koi carp, and catfish were demonstrated to be highly susceptible while goldfish and climbing perch were found to be moderately susceptible to the EUS infection. These findings suggested that the cellular response of fish to mycotic infection and granulomatous reaction varied in different fish species, which could not be an indicator of susceptibility or resistant to the EUS itself, although it was shown that the granulation rate and the level of

A theory of generalized Bloch oscillations

DEFF Research Database (Denmark)

Duggen, Lars; Lew Yan Voon, L. C.; Lassen, Benny

2016-01-01

Bloch oscillations of electrons are shown to occur for cases when the energy spectrum does not consist of the traditional evenly-spaced ladders and the potential gradient does not result from an external electric field. A theory of such generalized Bloch oscillations is presented and an exact...... oscillations. We stipulate that the presented theory of generalized Bloch oscillations can be extended to other systems such as acoustics and photonics....

Electric dipoles on the Bloch sphere

OpenAIRE

Vutha, Amar C.

2014-01-01

The time evolution of a two-level quantum mechanical system can be geometrically described using the Bloch sphere. By mapping the Bloch sphere evolution onto the dynamics of oscillating electric dipoles, we provide a physically intuitive link between classical electromagnetism and the electric dipole transitions of atomic & molecular physics.

Electric dipoles on the Bloch sphere

International Nuclear Information System (INIS)

Vutha, Amar C

2015-01-01

The time evolution of a two-level quantum mechanical system can be geometrically described using the Bloch sphere. By mapping the Bloch sphere evolution onto the dynamics of oscillating electric dipoles, we provide a physically intuitive link between classical electromagnetism and the electric dipole transitions of atomic and molecular physics. (paper)

Prevalence of Haplorchis taichui and Haplorchoides sp. Metacercariae in Freshwater Fish from Water Reservoirs, Chiang Mai, Thailand

Science.gov (United States)

Nithikathkul, Choosak

2008-01-01

A parasitological investigation on trematode metacercariae was made on 62 freshwater fishes of 13 species in northern Thailand; Cyclocheilichthys apogon, Puntioplites proctozysron, Labiobarbus siamensis, Barbodes gonionotus, Barbodes altus, Henicorhynchus siamensis, Osteochilus hasselti, Notopterus notopterus, Mystacoleucus marginatus, Anabas testudineus, Systomus orphoides, Morulius chrysophykadian, and Hampala macrolepidota. The fish were caught over the summer period (February-May 2007) from 2 Chiang Mai water reservoirs, i.e., the Mae Ngad (UTM 47Q E 503200, 47Q N 2119300) and the Mae Kuang Udomtara (UTM 47Q E 513000, 47Q N 2092600) Reservoirs in Chiang Mai province, Thailand. The prevalence of heterophyid (Haplorchis taichui and Haplorchoides sp.) metacercariae in these fish was 83.9% and 74.2% in the Mae Ngad and Mae Kuang Udomtara Reservoirs, respectively. The highest intensity of heterophyid metacercariae in H. siamensis in the Mae Ngad was 120.4 and that in P. proctozysron in the Mae Kuang Udomtara was 180.0. The fish, A. testudineus, C. apogon, and M. chrysophykadian, were not found to be infected with H. taichui metacercariae. The results show that the freshwater fish in Chiang Mai water reservoirs are heavily infected with H. taichui and Haplorchoides sp. metacercariae. PMID:18552549

Squeezing corrections to the Bloch equations

International Nuclear Information System (INIS)

Abundo, M.; Accardi, L.

1991-01-01

The general analysis of quantum noise shows that a squeezing noise can produce quadratic nonlinearities in the Langevin equations leading to the Bloch equations. These quadratic nonlinearities are governed by the imaginary part of the off-diagonal terms of the covariance of the noise (the squeezing terms) and imply a correction to the usual form of the Bloch equations. Here the case of spin-one nuclei subjected to squeezing noises of particular type is studied numerically. It is shown that the corrections to the Bloch equations, suggested by the theory, to the behaviour of the macroscopic nuclear polarization in a scale of times of the order of the relaxation time can be quite substantial. In the equilibrium regime, even if the qualitative behaviour of the system is the same (exponential decay), the numerical equilibrium values predicted by the theory are consistently different from those predicted by the usual Bloch equation. It is suggested that this difference might be used to test experimentally the observable effects of squeezing noises

Quantum anomalous Bloch-Siegert shift in Weyl semimetal

Science.gov (United States)

Kumar, Upendra; Kumar, Vipin; Enamullah, Setlur, Girish S.

2018-05-01

A periodic exchange of energy between the light field and two level system is known as Rabi oscillations. The Bloch-Siegert shift (BSS) is a shift in Rabi oscillation resonance condition, when the driving field is sufficiently strong. There are new type of oscillations exhibit in Weyl semimetal at far from resonance, known as anomalous Rabi oscillation. In this work, we study the phenomenon of the Bloch-Siegert shift in Weyl semimetal at far from resonance called anomalous Bloch-Siegert shift (ABSS) by purely quantum mechanical treatment and describe it's anisotropic nature. A fully numerical solution of the Floquet-Bloch equations unequivocally establishes the presence of not only anomalous Rabi oscillations in these systems but also their massless character.

On history and salvation in Emmanuel Levinas and Ernst Bloch

African Journals Online (AJOL)

p1243322

“Chronos” who devours his own children.13 In addition to this, one would invert ... death” against Bloch, one could argue that Bloch, in effect, is glorifying death .... fantasy or wishful thinking) to Bloch's belief that in a humanised world the.

Chaotic dynamics in the Maxwell-Bloch equations

International Nuclear Information System (INIS)

Holm, D.D.; Kovacic, G.

1992-01-01

In the slowly varying envelope approximation and the rotating wave approximation for the Maxwell-Bloch equations, we describe how the presence of a small-amplitude probe laser in an excited, two-level, resonant medium leads to homoclinic chaos in the laser-matter dynamics. We also describe a derivation of the Maxwell-Bloch equations from an action principle

Composition operators between Bloch type spaces and Zygmund ...

Indian Academy of Sciences (India)

MS received 1 September 2009; revised 31 March 2011. Abstract. The boundedness and compactness of composition operators between. Bloch type spaces and Zygmund spaces of holomorphic functions in the unit ball are characterized in the paper. Keywords. Composition operator; Bloch type space; Zygmund space. 1.

Bloch-Siegert shift in Dirac-Weyl fermionic systems

Science.gov (United States)

Kumar, Upendra; Kumar, Vipin; Enamullah, Setlur, Girish S.

2018-04-01

The Bloch-Siegert shift is a phenomenon in quantum optics, typically seen in two-level systems, when the driving field is sufficiently strong. The inclusion of frequency doubling effect (counter rotating term) in the conventional rotating wave approximation (RWA) changes the resonance condition thereby producing a rather small shift in the resonance condition, which is known as the Bloch-Siegert shift (BSS). Rabi oscillations in Dirac-Weyl fermionic systems exhibit anomalous behavior far from resonance, called anomalous Rabi oscillations. Therefore, in the present work, we study the phenomenon of the Bloch-Siegert shift in Weyl semimetal and topological insulator (TI) far from resonance, called anomalous Bloch-Siegert shift (ABSS). It is seen that the change in the resonance condition of anomalous Rabi oscillations is drastic in Weyl semimetal and TI. The ABSS in Weyl semimetals is highly anisotropic, whereas it is isotropic in TI. In case of TI, it is the Chern number which plays a crucial role to produce substantial change in the ABSS.

The basic properties of Bloch functions

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Joseph A. Cima

1979-01-01

Full Text Available A Bloch function f(z is an analytic function on the unit disc whose derivative grows no faster than a constant times the reciprocal of the distance from z to ∂. We reprove here the basic analytic facts concerning Bloch functions. We establish the Banach space structure and collect facts concerning the geometry of the space. We indicate duality relationships, and known isomorphic correspondences are given. We give a rather complete list of references for further study in the case of several variables.

Skyrmion clusters from Bloch lines in ferromagnetic films

KAUST Repository

Garanin, Dmitry A.

2017-12-29

Conditions under which various skyrmion objects emerge in experiments on thin magnetic films remain largely unexplained. We investigate numerically centrosymmetric spin lattices in films of finite thickness with ferromagnetic exchange, magnetic anisotropy, and dipole-dipole interaction. Evolution of labyrinth domains into compact topological structures on application of the magnetic field is found to be governed by the configuration of Bloch lines inside domain walls. Depending on the combination of Bloch lines, the magnetic domains evolve into individual skyrmions, biskyrmions, or more complex topological objects. While the geometry of such objects is sensitive to the parameters, their topological charge is uniquely determined by the topological charge of Bloch lines inside the magnetic domain from which the object emerges.

Bloch-mode analysis for retrieving effective parameters of metamaterials

DEFF Research Database (Denmark)

Andryieuski, Andrei; Ha, Sangwoo; Sukhorukov, Andrey A.

2012-01-01

by our method with a high accuracy. We employ both surface and volume averaging of the electromagnetic fields of the dominating (fundamental) Bloch modes to determine the Bloch and wave impedances, respectively. We discuss how this method works for several characteristic examples, and demonstrate...

Bloch walls in a nickel single crystal

International Nuclear Information System (INIS)

Peters, J.; Treimer, W.

2001-01-01

We present a consistent theory for the dependence of the magnetic structure in bulk samples on external static magnetic fields and corresponding experimental results. We applied the theory of micromagnetism to this crystal and calculated the Bloch wall thickness as a function of external magnetic fields. The theoretical results agree well with the experimental data, so that the Bloch wall thickness of a 71 deg. nickel single crystal was definitely determined with some hundred of nanometer

Non-Bloch decay of Rabi oscillations in liquid state NMR

Science.gov (United States)

Chakrabarti, Arnab; Bhattacharyya, Rangeet

2018-03-01

Rabi oscillations are known to exhibit non-Bloch behaviour in anisotropic media. In this letter, we report an experimental observation of non-Bloch decay of Rabi oscillations in isotropic liquid state NMR. To avoid the dephasing due to the radio-frequency inhomogeneities, we develop a modified version of the rotary echo protocol and use it to determine the decay rates of Rabi oscillations. We find that the measured decay rates are proportional to the square of the Rabi frequencies and the proportionality constant is of the order of tens of picoseconds. Further, we show that this non-Bloch nature of the decay rates becomes less prominent with increasing temperature. The implications of the presence of non-Bloch decay rates in liquid state NMR in the context of ensemble quantum computing are also discussed.

Variational principle for the Bloch unified reaction theory

International Nuclear Information System (INIS)

MacDonald, W.; Rapheal, R.

1975-01-01

The unified reaction theory formulated by Claude Bloch uses a boundary value operator to write the Schroedinger equation for a scattering state as an inhomogeneous equation over the interaction region. As suggested by Lane and Robson, this equation can be solved by using a matrix representation on any set which is complete over the interaction volume. Lane and Robson have proposed, however, that a variational form of the Bloch equation can be used to obtain a ''best'' value for the S-matrix when a finite subset of this basis is used. The variational principle suggested by Lane and Robson, which gives a many-channel S-matrix different from the matrix solution on a finite basis, is considered first, and it is shown that the difference results from the fact that their variational principle is not, in fact, equivalent to the Bloch equation. Then a variational principle is presented which is fully equivalent to the Bloch form of the Schroedinger equation, and it is shown that the resulting S-matrix is the same as that obtained from the matrix solution of this equation. (U.S.)

Modeling Bloch oscillations in nanoscale Josephson junctions

Science.gov (United States)

Vora, Heli; Kautz, R. L.; Nam, S. W.; Aumentado, J.

2018-01-01

Bloch oscillations in nanoscale Josephson junctions with a Coulomb charging energy comparable to the Josephson coupling energy are explored within the context of a model previously considered by Geigenmüller and Schön that includes Zener tunneling and treats quasiparticle tunneling as an explicit shot-noise process. The dynamics of the junction quasicharge are investigated numerically using both Monte Carlo and ensemble approaches to calculate voltage-current characteristics in the presence of microwaves. We examine in detail the origin of harmonic and subharmonic Bloch steps at dc biases I = (n/m)2ef induced by microwaves of frequency f and consider the optimum parameters for the observation of harmonic (m = 1) steps. We also demonstrate that the GS model allows a detailed semiquantitative fit to experimental voltage-current characteristics previously obtained at the Chalmers University of Technology, confirming and strengthening the interpretation of the observed microwave-induced steps in terms of Bloch oscillations. PMID:29577106

Bloch spaces of holomorphic functions in the polydisk

Directory of Open Access Journals (Sweden)

Anahit Harutyunyan

2007-01-01

Full Text Available This work is an introduction to anisotropic spaces of holomorphic functions, which have ω-weight and are generalizations of Bloch spaces to a polydisc. We prove that these classes form an algebra and are invariant with respect to monomial multiplication. Some theorems on projection and diagonal mapping are proved. We establish a description of (Ap(ω* (or (Hp(ω* via the Bloch classes for all 0

Spin wave vortex from the scattering on Bloch point solitons

Energy Technology Data Exchange (ETDEWEB)

Carvalho-Santos, V.L., E-mail: vagson.carvalho@usach.cl [Instituto Federal de Educação, Ciência e Tecnologia Baiano - Campus Senhor do Bonfim, Km 04 Estrada da Igara, 48970-000 Senhor do Bonfim, Bahia (Brazil); Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Elías, R.G., E-mail: gabriel.elias@usach.cl [Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Nunez, A.S., E-mail: alnunez@dfi.uchile.cl [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Casilla 487-3, Santiago (Chile)

2015-12-15

The interaction of a spin wave with a stationary Bloch point is studied. The topological non-trivial structure of the Bloch point manifests in the propagation of spin waves endowing them with a gauge potential that resembles the one associated with the interaction of a magnetic monopole and an electron. By pursuing this analogy, we are led to the conclusion that the scattering of spin waves and Bloch points is accompanied by the creation of a magnon vortex. Interference between such a vortex and a plane wave leads to dislocations in the interference pattern that can be measurable by means of magnon holography.

Modeling Bloch oscillations in ultra-small Josephson junctions

Science.gov (United States)

Vora, Heli; Kautz, Richard; Nam, Sae Woo; Aumentado, Jose

In a seminal paper, Likharev et al. developed a theory for ultra-small Josephson junctions with Josephson coupling energy (Ej) less than the charging energy (Ec) and showed that such junctions demonstrate Bloch oscillations which could be used to make a fundamental current standard that is a dual of the Josephson volt standard. Here, based on the model of Geigenmüller and Schön, we numerically calculate the current-voltage relationship of such an ultra-small junction which includes various error processes present in a nanoscale Josephson junction such as random quasiparticle tunneling events and Zener tunneling between bands. This model allows us to explore the parameter space to see the effect of each process on the width and height of the Bloch step and serves as a guide to determine whether it is possible to build a quantum current standard of a metrological precision using Bloch oscillations.

Heterobothrium lamothei n. sp. (Monogenea: Diclidophoridae from the gills of Sphoeroides testudineus (Pisces: Tetraodontidae from the coast of Yucatán, Mexico Heterobothrium lamothei n. sp. (Monogenea: Diclidophoridae de las branquias de Sphoeroides testudineus (Pisces: Tetraodontidae de la costa de Yucatán, México

Directory of Open Access Journals (Sweden)

Víctor M. Vidal-Martínez

2008-08-01

Full Text Available The presence of a member of the genus Heterobothrium is described for the first time from the coast of Yucatán Peninsula, southeastern Mexico. Heterobothrium lamothei n. sp. is recorded parasitizing the gills of the tetraodontid fish Sphoeroides testudineus (Linnaeus, 1758 from 4 coastal lagoons in Yucatán: Celestún (20° 52' N, 90° 24' W, Chelem (21°15'N89°45'W, Dzilam (21°35'N 88°35'W and Río Lagartos (21°22'N 87°30'W. The new species differs from the other species described in the genus, by a combination of characters including a copulatory organ armed with 12-15 genital hooks, the distal pair of clamps smaller in comparison with the 3 other pairs and by having 15-26 testes. The infection parameters were for Celestun, 47 % of prevalence, number of fish examined (n = 47, mean abundance of 1.76 ± 9.62; Chelem, 20 % (n = 30, 0.53 ± 8.48; Dzilam, 2 % (n = 60, 0.02 ± 0.00; Río Lagartos, 25 % (n = 59, 0.34 ± 1.58. Heterobothrium lamothei n. sp. may be considered as potentially dangerous species for the aquaculture of S. testudineus due to its direct life cycle hat high fish densities would increase the transmission of this monogenean.Se registra por primera vez la presencia de un miembro del género Heterobothrium en la costa de la península de Yucatán, México: Heterobothrium lamothei n. sp., parásito de las branquias del pez tetraodóntido Sphoeroides testudineus (Linnaeus, 1758 en 4 lagunas costeras de Yucatán: Celestún (20° 52' N, 90° 24' O, Chelem (21°15'N89°45'O, Dzilam (21°35'N 88°35'O y Río Lagartos (21°22'N 87°30'O. La especie nueva difiere de otras del género por un conjunto de características que incluyen un órgano copulador con 12 a 15 ganchos genitales, un par distal de pinzas más pequeño que los 3 pares superiores y un número reducido de testículos (15-26. Los parámetros de infección para las 4 localidades fueron: Celestún: 47 % de prevalencia, 47 peces examinados (n = 47, abundancia media de 1

Orbital magnetism of Bloch electrons I. General formula

International Nuclear Information System (INIS)

Ogata, Masao; Fukuyama, Hidetoshi

2015-01-01

We derive an exact formula of orbital susceptibility expressed in terms of Bloch wave functions, starting from the exact one-line formula by Fukuyama in terms of Green's functions. The obtained formula contains four contributions: (1) Landau-Peierls susceptibility, (2) interband contribution, (3) Fermi surface contribution, and (4) contribution from occupied states. Except for the Landau-Peierls susceptibility, the other three contributions involve the crystal-momentum derivatives of Bloch wave functions. Physical meaning of each term is clarified. The present formula is simplified compared with those obtained previously by Hebborn et al. Based on the formula, it is seen first of all that diamagnetism from core electrons and Van Vleck susceptibility are the only contributions in the atomic limit. The band effects are then studied in terms of linear combination of atomic orbital treating overlap integrals between atomic orbitals as a perturbation and the itinerant feature of Bloch electrons in solids are clarified systematically for the first time. (author)

A formula for the Bloch vector of some Lindblad quantum systems

International Nuclear Information System (INIS)

Salgado, D.; Sanchez-Gomez, J.L.

2004-01-01

Using the Bloch representation of an N-dimensional quantum system and immediate results from quantum stochastic calculus, we establish a closed formula for the Bloch vector, hence also for the density operator, of a quantum system following a Lindblad evolution with selfadjoint Lindblad operators

From Bloch to random lasing in ZnO self-assembled nanostructures

DEFF Research Database (Denmark)

Garcia-Fernandez, Pedro David; Cefe, López

2013-01-01

In this paper, we present measurements on UV lasing in ZnO ordered and disordered nanostructures. Bloch lasing is achieved in the ordered structures by exploiting very low group-velocity Bloch modes in ZnO photonic crystals. In the second case, random lasing is observed in ZnO photonic glasses. We...... study the lasing threshold in both cases and its dependence on the structural parameters. Finally, we present the transition from Bloch to random lasing by deliberately doping a ZnO inverse photonic crystal with a controlled amount of lattice vacancies effectively converting it into a translationally...

Felix Bloch (1905–1983)

Indian Academy of Sciences (India)

IAS Admin

1905, to Jewish parents, Gustav and Agnes Bloch. The year he ... Both the student and the supervisor were in their 20's, separated by 5– ... up on the West Coast, in the University of Stanford, where he stayed for the rest of his academic life.

Properties of Floquet-Bloch space harmonics in 1D periodic magneto-dielectric structures

DEFF Research Database (Denmark)

Breinbjerg, O.

2012-01-01

Recent years have witnessed a significant research interest in Floquet-Bloch analysis for determining the homogenized permittivity and permeability of metamaterials consisting of periodic structures. This work investigates fundamental properties of the Floquet-Bloch space harmonics in a 1......-dimensional magneto-dielectric lossless structure supporting a transverse-electric-magnetic Floquet-Bloch wave; in particular, the space harmonic permittivity and permeability, as well as the space harmonic Poynting vector....

Computational Modeling of Bloch Surface Waves in One-Dimensional Periodic and Aperiodic Multilayer Structures

Science.gov (United States)

Koju, Vijay

Photonic crystals and their use in exciting Bloch surface waves have received immense attention over the past few decades. This interest is mainly due to their applications in bio-sensing, wave-guiding, and other optical phenomena such as surface field enhanced Raman spectroscopy. Improvement in numerical modeling techniques, state of the art computing resources, and advances in fabrication techniques have also assisted in growing interest in this field. The ability to model photonic crystals computationally has benefited both the theoretical as well as experimental communities. It helps the theoretical physicists in solving complex problems which cannot be solved analytically and helps to acquire useful insights that cannot be obtained otherwise. Experimentalists, on the other hand, can test different variants of their devices by changing device parameters to optimize performance before fabrication. In this dissertation, we develop two commonly used numerical techniques, namely transfer matrix method, and rigorous coupled wave analysis, in C++ and MATLAB, and use two additional software packages, one open-source and another commercial, to model one-dimensional photonic crystals. Different variants of one-dimensional multilayered structures such as perfectly periodic dielectric multilayers, quasicrystals, aperiodic multilayer are modeled, along with one-dimensional photonic crystals with gratings on the top layer. Applications of Bloch surface waves, along with new and novel aperiodic dielectric multilayer structures that support Bloch surface waves are explored in this dissertation. We demonstrate a slow light configuration that makes use of Bloch Surface Waves as an intermediate excitation in a double-prism tunneling configuration. This method is simple compared to the more usual techniques for slowing light using the phenomenon of electromagnetically induced transparency in atomic gases or doped ionic crystals operated at temperatures below 4K. Using a semi

[Feeding habits of sphoeroides testudineus (Perciformes: Tetraodontidae) in the lagoon system of Ria Lagartos, Yucatán, Mexico].

Science.gov (United States)

Chi-Espínola, Ariel Adriano; Vega-Cendejas, Maria Eugenia

2013-06-01

Sphoeroides testudineus is a dominant species in the coastal systems of Yucatán. Because of its wide distribution, occurrence and abundance performs an important functional role in coastal ecosystems. We assessed the trophic preferences and trophic-level variation in space and time for this species in Ria Lagartos lagoon, an hyperhaline ecosystem located Northwest of Yucatan Peninsula. The specimens were collected bimonthly during two annual periods (2004-2005 and 2007-2008) in 23 sites distributed along the system into four zones (marine, channel, Coloradas West and Coloradas East). Spatial and seasonal trophic variations were evaluated using canonical correspondence analysis (ACC). In a total of 382 individuals, 68 food resources included in 20 trophic groups were obtained. Higher relative importance index values (IIR) were obtained for bivalves, gastropods and macrophytes. Seasonal trophic variation showed that bivalves and gastropods were consumed along the year, while macrophytes were a preferential food during rains and windy seasons. Spatial variation indicates lower gastropods consumption at the inner zone of the system, and the opposite ocurred with bivalves. The consumption ofmacrophytes may be due to their greater abundance during rains and in the channel zone. The ACC showed that spatial trophic variation was due because of the abundance of the preferential preys (bivalves, gastropods), while seasonal differences by the secondary (amphipods, eggs, nematodes, brachyuran, detritus, nematodes). The results contribute to the biological knowledge of the species and highlight the importance and trophic function of S testudineus for the energy transfer from the benthos to higher trophic levels of the food chain.

Endosulfan residues in fish from the MUDA rice agroecosystem

International Nuclear Information System (INIS)

Nashriyah Mat; Sabri Junoh; Nuriati Nurdin

2002-01-01

A study was carried out in the recycled and the non-recycled areas of the Muda rice agroecosystem to determine the residue level of endosulfan in rice field fish. Snakehead or haruan (Channa striata), climbing perch or puyu (Anabas testudineus), walking catfish or keli (Clariasspp.) and snakeskin gouramy or sepat siam (Trichogasterpectoralis) were sampled and the tissues analysed using Gas Liquid Chromatography. Endosulfan sulphate metabolite was a ubiquitous residue in all fish at levels ranging from 0.0065 μg/g to 0.9837 μg/g of tissue wet weight whilst α-isomer was detected at a much lower concentration followed by β-isomer. In Channa striata, endosulfan total residue (α+β+sulphate) was accumulated in fish tissues sampled at ACRBD4 (non-recycled) site followed by Blok 14 (recycled) site. Endosulfan residue concentration did not coincide with water recycling practice nor changes in EROD enzyme activity. (Author)

Weighted Composition Operators from Hardy Spaces into Logarithmic Bloch Spaces

Directory of Open Access Journals (Sweden)

Flavia Colonna

2012-01-01

Full Text Available The logarithmic Bloch space Blog⁡ is the Banach space of analytic functions on the open unit disk 𝔻 whose elements f satisfy the condition ∥f∥=sup⁡z∈𝔻(1-|z|2log⁡  (2/(1-|z|2|f'(z|<∞. In this work we characterize the bounded and the compact weighted composition operators from the Hardy space Hp (with 1≤p≤∞ into the logarithmic Bloch space. We also provide boundedness and compactness criteria for the weighted composition operator mapping Hp into the little logarithmic Bloch space defined as the subspace of Blog⁡ consisting of the functions f such that lim⁡|z|→1(1-|z|2log⁡  (2/(1-|z|2|f'(z|=0.

Bloch wave deafness and modal conversion at a phononic crystal boundary

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Vincent Laude

2011-12-01

Full Text Available We investigate modal conversion at the boundary between a homogeneous incident medium and a phononic crystal, with consideration of the impact of symmetry on the excitation of Bloch waves. We give a quantitative criterion for the appearance of deaf Bloch waves, which are antisymmetric with respect to a symmetry axis of the phononic crystal, in the frame of generalized Fresnel formulas for reflection and transmission at the phononic crystal boundary. This criterion is used to index Bloch waves in the complex band structure of the phononic crystal, for directions of incidence along a symmetry axis. We argue that within deaf frequency ranges transmission is multi-exponential, as it is within frequency band gaps.

Hábitos alimenticios de Sphoeroides testudineus (Perciformes: Tetraodontidae en el sistema lagunar de Ría Lagartos, Yucatán, México Feeding habits of Sphoeroides testudineus (Perciformes: Tetraodontidae in the lagoon system of Ria Lagartos, Yucatán, Mexico

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Ariel Adriano Chi-Espínola

2013-06-01

Full Text Available Sphoeroides testudineus, es una especie dominante en los sistemas costeros de Yucatán. Debido a su amplia distribución, ocurrencia y abundancia realiza un importante papel funcional en los ecosistemas costeros. Evaluamos para esta especie las preferencias tróficas y su variación a nivel espacial y temporal en la laguna de Ría Lagartos, un ecosistema hiperhalino localizado al noroeste de la península de Yucatán. Los especímenes fueron recolectados bimensualmente durante dos periodos anuales (2004-2005 y 2007-2008 en 23 sitios distribuidos a lo largo del sistema en cuatro zonas (marina, canal, Coloradas oeste y Coloradas este. Las variaciones tróficas espaciales y temporales fueron evaluadas mediante un análisis de correspondencia canónica (ACC. En un total de 382 individuos, se obtuvieron 68 recursos alimenticios incluidos en 20 grupos tróficos. El mayor índice de importancia relativa (IIR lo obtuvieron los bivalvos, gasterópodos y macrófitas. La variación trófica estacional mostró que los bivalvos y gasterópodos son consumidos a lo largo del año, mientras que las macrófitas constituyeron el alimento preferencial en la temporada de lluvias y nortes. La variación espacial indica un bajo consumo de gasterópodos hacia el interior de la laguna, y lo opuesto sucedió con los bivalvos. El consumo de macrófitas pudo ser debido a su mayor abundancia durante lluvias y en la zona del canal. El ACC mostró que la variación trófica espacial se debió a la abundancia de las presas preferenciales (bivalvos y gasterópodos, mientras que las diferencias estacionales por las presas secundarias (anfípodos, huevos, nematodos, braquiuros, detritus, nemátodos. Los resultados contribuyen al conocimiento biológico de la especie y resaltan la importancia y función trófica de Sphoeroides testudineus en las transferencias de energía desde el bentos hacia los niveles tróficos superiores de la cadena alimenticia.Sphoeroides testudineus is a

Mechanical Properties of Laminate Materials: From Surface Waves to Bloch Oscillations

DEFF Research Database (Denmark)

Liang, Z.; Willatzen, Morten; Christensen, Johan

2015-01-01

for designing Bloch oscillations in classical plate structures and show how mechanical Bloch oscillations can be generated in arrays of solid plates when the modal wavelength is gradually reduced. The design recipe describes how Bloch oscillations in classical structures of arbitrary dimensions can be generated......We propose hitherto unexplored and fully analytical insights into laminate elastic materials in a true condensed-matter-physics spirit. Pure mechanical surface waves that decay as evanescent waves from the interface are discussed, and we demonstrate how these designer Scholte waves are controlled......, and we demonstrate this numerically for structures with millimeter and centimeter dimensions in the kilohertz to megahertz range. Analytical predictions agree entirely with full wave simulations showing how elastodynamics can mimic quantum-mechanical condensed-matter phenomena....

The Bloch Approximation in Periodically Perforated Media

International Nuclear Information System (INIS)

Conca, C.; Gomez, D.; Lobo, M.; Perez, E.

2005-01-01

We consider a periodically heterogeneous and perforated medium filling an open domain Ω of R N . Assuming that the size of the periodicity of the structure and of the holes is O(ε),we study the asymptotic behavior, as ε → 0, of the solution of an elliptic boundary value problem with strongly oscillating coefficients posed in Ω ε (Ω ε being Ω minus the holes) with a Neumann condition on the boundary of the holes. We use Bloch wave decomposition to introduce an approximation of the solution in the energy norm which can be computed from the homogenized solution and the first Bloch eigenfunction. We first consider the case where Ωis R N and then localize the problem for abounded domain Ω, considering a homogeneous Dirichlet condition on the boundary of Ω

Behaviour of neutrons passing through the Bloch wall

International Nuclear Information System (INIS)

Schaerpf, O.

1976-01-01

In part I of the present paper the pertinent knowledge about Bloch walls is presented and developed insofar as it appears necessary for the experiments with neutrons, that is to say the direction of magnetization within the domains, the calculation of the variation of magnetization in the wall, the wall thickness, and the zigzag structure of the Bloch wall. In part II it is first clarified why the Bloch wall can be treated as a continuum problem. It shows that this is possible far away from Laue reflexes. For angles far away from Laure-reflex angles the interaction of the periodic structure of the magnetization can be described with the aid of an averaged magnetic flux density. The consequence of it is the possibility of treating the problem by means of a Schroedinger equation with continous interaction. This leads to a law of refraction. The question of the possibilities for explaining the intensity behavior is treated in part III. This part, from different aspects, describes the fact, which already was pointed out in Schaerpf, O., Vehoff, H., Schwink, Ch. 1973, that the spin of the neutrons in passing through the wall is partly taken along by the magnetization gradually rotating in the wall. (orig./WBU) [de

Bloch-Surface-Polariton-Based Hybrid Nanowire Structure for Subwavelength, Low-Loss Waveguiding

Directory of Open Access Journals (Sweden)

Weijing Kong

2018-03-01

Full Text Available Surface plasmon polaritons (SPPs have been thoroughly studied in the past decades for not only sensing but also waveguiding applications. Various plasmonic device structures have been explored due to their ability to confine their optical mode to the subwavelength level. However, with the existence of metal, the large ohmic loss limits the propagation distance of the SPP and thus the scalability of such devices. Therefore, different hybrid waveguides have been proposed to overcome this shortcoming. Through fine tuning of the coupling between the SPP and a conventional waveguide mode, a hybrid mode could be excited with decent mode confinement and extended propagation distance. As an effective alternative of SPP, Bloch surface waves have been re-investigated more recently for their unique advantages. As is supported in all-dielectric structures, the optical loss for the Bloch surface wave is much lower, which stands for a much longer propagating distance. Yet, the confinement of the Bloch surface wave due to the reflections and refractions in the multilayer structure is not as tight as that of the SPP. In this work, by integrating a periodic multilayer structure that supports the Bloch surface wave with a metallic nanowire structure, a hybrid Bloch surface wave polariton could be excited. With the proposed hybrid nanowire structure, a hybrid mode is demonstrated with the deep subwavelength mode confinement and a propagation distance of tens of microns.

PENGGUNAAN MERK NILON YANG BERBEDA PADA LALANGIT (Horizontal gillnet TERHADAP HASIL TANGKAPAN IKAN BETOK (Anabas testudineus (THE USE OF MARQUE NYLON DIFFERENT ON LALANGIT (Horizontal Gillnet AGAINST THE CATCH FISH BETOK (Anabas Testudineus

Directory of Open Access Journals (Sweden)

Siti Aminah

2017-02-01

Full Text Available Tujuan dari Penelitian ini adalah untuk mengetahui (1 deskripsi lalat tangkap Lalangit yang biasa digunakan, (2 jumlah hasil tangkapan (catch yang diperoleh dari perbedaan beberapa merk nilon yang digunakan, (3 merk nilon yang terbaik sebagai bahan material lalangit (horizontal gillnet.  Metode penelitian yang digunakan adalah Rancangan Acak Kelompok (RAK dengan 6 perlakuan yaitu 6 jenis merk nilon yang berbeda.  Dari hasil penelitian   diperoleh jumlah hasil tangkapan yang paling banyak pada Lalangit yang menggunakan nilon merk damyl memperoleh jumlah hasil tangkapan sebanyak 50 ekor dengan berat total 1.728 gram,karena dari segi konstruksi atau bahan materialnya lembut yang menyebabkan hasil tangkapan tidak mudah meloloskan diri dari jaring karena ke elastisitasan dan warna biru dari nilon dapat menyerupai kondisi perairan sehingga ikan mudah tertipu keadaan daerah perairan tersebut dan didapatkan hasil tangkapan yang optimal. The purpose of this research is to know (1 the description of the commonly used lalangit, (2 the amount of the catch (catch are obtained from the difference in some brands of nylon that is used, (3 brands of nylon materials as the best lalangit (horizontal gillnet. The research method used was Random Design Group (RAK with 6 treatments IE 6 types of different brands of nylon. Of research results obtained the most number of catches a lot on Lalangit using the brand damyl earn 50 catches the tail with a total weight of 1.728 gram, because in terms of construction or its material soft materials that cause the catch is not easy to escape from nets due to elastisitasan and the blue color of nylon can resemble aquatic conditions so that the gullible fish State of the waters and the obtained results the optimal catch.

Bloch electrons in 2D periodic electric and magnetic fields; Bloch-Elektronen in 2D periodischen elektrischen und magnetischen Feldern

Energy Technology Data Exchange (ETDEWEB)

Naundorf, B.

2001-06-01

The following topics were dealt with: electrons in periodic potentials, Bloch states, Landau states, wave packets, Harper equation, uncoupled Landau band states, matrix elements and matrix equations, periodic electric and magnetic fields (WL)

Terahertz emission of Bloch oscillators excited by electromagnetic field in lateral semiconductor superlattices

International Nuclear Information System (INIS)

Dodin, E.P.; Zharov, A.A.

2003-01-01

The effect of the strong high-frequency electromagnetic field on the lateral semiconductor superlattice is considered on the basis of the quasi-classical theory on the electron transport in the self-consistent wave arrangement. It is theoretically identified, that the lateral superlattice in the strong feed-up wave field may emit the terahertz radiation wave trains, which are associated with the periodical excitation of the Bloch oscillations in the superlattice. The conditions, required for the Bloch oscillators radiation observation, are determined. The spectral composition of the radiation, passing through the superlattice, and energy efficiency of multiplying the frequency, related to the Bloch oscillator excitation, are calculated [ru

Optical Effects Induced by Bloch Surface Waves in One-Dimensional Photonic Crystals

Directory of Open Access Journals (Sweden)

Irina V. Soboleva

2018-01-01

Full Text Available The review considers the influence of Bloch surface waves on the optical and magneto-optical effects observed in photonic crystals; for example, the Goos–Hänchen effect, the Faraday effect, optical trapping and so on. Prospects for using Bloch surface waves for spatial light modulation, for controlling the polarization of light, for optical trapping and control of micro-objects are discussed.

Bloch oscillations and accelerated Bose–Einstein condensates in an optical lattice

Energy Technology Data Exchange (ETDEWEB)

Sacchetti, Andrea, E-mail: andrea.sacchetti@unimore.it

2017-01-30

Highlights: • Discrete nonlinear Schrödinger model for accelerated BECs in optical lattices. • Numerical computation of wavefunction BECs dynamics. • Correlation between nonlinearity and the oscillating period of the BEC's center of mass. • Discussion of the validity of the Bloch Theorem for accelerated BECs in an optical lattice. - Abstract: We discuss the method for the measurement of the gravity acceleration g by means of Bloch oscillations of an accelerated BEC in an optical lattice. This method has a theoretical critical point due to the fact that the period of the Bloch oscillations depends, in principle, on the initial shape of the BEC wavepacket. Here, by making use of the nearest-neighbor model for the numerical analysis of the BEC wavefunction, we show that in real experiments the period of the Bloch oscillations does not really depend on the shape of the initial wavepacket and that the relative uncertainty, due to the fact that the initial shape of the wavepacket may be asymmetrical, is smaller than the one due to experimental errors. Furthermore, we also show that the relation between the oscillation period and the scattering length of the BEC's atoms is linear; this fact suggests us a new experimental procedure for the measurement of the scattering length of atoms.

Vacuum Bloch-Siegert shift in Landau polaritons with ultra-high cooperativity

Science.gov (United States)

Li, Xinwei; Bamba, Motoaki; Zhang, Qi; Fallahi, Saeed; Gardner, Geoff C.; Gao, Weilu; Lou, Minhan; Yoshioka, Katsumasa; Manfra, Michael J.; Kono, Junichiro

2018-06-01

A two-level system resonantly interacting with an a.c. magnetic or electric field constitutes the physical basis of diverse phenomena and technologies. However, Schrödinger's equation for this seemingly simple system can be solved exactly only under the rotating-wave approximation, which neglects the counter-rotating field component. When the a.c. field is sufficiently strong, this approximation fails, leading to a resonance-frequency shift known as the Bloch-Siegert shift. Here, we report the vacuum Bloch-Siegert shift, which is induced by the ultra-strong coupling of matter with the counter-rotating component of the vacuum fluctuation field in a cavity. Specifically, an ultra-high-mobility two-dimensional electron gas inside a high-Q terahertz cavity in a quantizing magnetic field revealed ultra-narrow Landau polaritons, which exhibited a vacuum Bloch-Siegert shift up to 40 GHz. This shift, clearly distinguishable from the photon-field self-interaction effect, represents a unique manifestation of a strong-field phenomenon without a strong field.

Chaos synchronization of nonlinear Bloch equations

International Nuclear Information System (INIS)

Park, Ju H.

2006-01-01

In this paper, the problem of chaos synchronization of Bloch equations is considered. A novel nonlinear controller is designed based on the Lyapunov stability theory. The proposed controller ensures that the states of the controlled chaotic slave system asymptotically synchronizes the states of the master system. A numerical example is given to illuminate the design procedure and advantage of the result derived

Skyrmion clusters from Bloch lines in ferromagnetic films

KAUST Repository

Garanin, Dmitry A.; Chudnovsky, Eugene M.; Zhang, Xixiang

2017-01-01

anisotropy, and dipole-dipole interaction. Evolution of labyrinth domains into compact topological structures on application of the magnetic field is found to be governed by the configuration of Bloch lines inside domain walls. Depending on the combination

Observation of Bloch oscillations in complex PT-symmetric photonic lattices

Science.gov (United States)

Wimmer, Martin; Miri, Mohammed-Ali; Christodoulides, Demetrios; Peschel, Ulf

2015-01-01

Light propagation in periodic environments is often associated with a number of interesting and potentially useful processes. If a crystalline optical potential is also linearly ramped, light can undergo periodic Bloch oscillations, a direct outcome of localized Wannier-Stark states and their equidistant eigenvalue spectrum. Even though these effects have been extensively explored in conservative settings, this is by no means the case in non-Hermitian photonic lattices encompassing both amplification and attenuation. Quite recently, Bloch oscillations have been predicted in parity-time-symmetric structures involving gain and loss in a balanced fashion. While in a complex bulk medium, one intuitively expects that light will typically follow the path of highest amplification, in a periodic system this behavior can be substantially altered by the underlying band structure. Here, we report the first experimental observation of Bloch oscillations in parity-time-symmetric mesh lattices. We show that these revivals exhibit unusual properties like secondary emissions and resonant restoration of PT symmetry. In addition, we present a versatile method for reconstructing the real and imaginary components of the band structure by directly monitoring the light evolution during a cycle of these oscillations. PMID:26639941

Integral type operators from normal weighted Bloch spaces to QT,S spaces

Directory of Open Access Journals (Sweden)

Yongyi GU

2016-08-01

Full Text Available Operator theory is an important research content of the analytic function space theory. The discussion of simultaneous operator and function space is an effective way to study operator and function space. Assuming that  is an analytic self map on the unit disk Δ, and the normal weighted bloch space μ-B is a Banach space on the unit disk Δ, defining a composition operator C∶C(f=f on μ-B for all f∈μ-B, integral type operator JhC and CJh are generalized by integral operator and composition operator. The boundeness and compactness of the integral type operator JhC acting from normal weighted Bloch spaces to QT,S spaces are discussed, as well as the boundeness of the integral type operators CJh acting from normal weighted Bloch spaces to QT,S spaces. The related sufficient and necessary conditions are given.

Reve et action: Bloch, Heidegger et Levinas

Czech Academy of Sciences Publication Activity Database

Bierhanzl, Jan

2016-01-01

Roč. 12, č. 3 (2016), s. 1-6 ISSN 1336-6556 R&D Projects: GA ČR(CZ) GA16-23046S Institutional support: RVO:67985955 Keywords : possibility * wishing * decision * action * dream * utopia Subject RIV: AA - Philosophy ; Religion http://www.ostium.sk/sk/r%C8%87ve-er-action-bloch-heidegger-et-levinas/

Quasiperiodicity in time evolution of the Bloch vector under the thermal Jaynes-Cummings model

Science.gov (United States)

Azuma, Hiroo; Ban, Masashi

2014-07-01

We study a quasiperiodic structure in the time evolution of the Bloch vector, whose dynamics is governed by the thermal Jaynes-Cummings model (JCM). Putting the two-level atom into a certain pure state and the cavity field into a mixed state in thermal equilibrium at initial time, we let the whole system evolve according to the JCM Hamiltonian. During this time evolution, motion of the Bloch vector seems to be in disorder. Because of the thermal photon distribution, both a norm and a direction of the Bloch vector change hard at random. In this paper, taking a different viewpoint compared with ones that we have been used to, we investigate quasiperiodicity of the Bloch vector’s trajectories. Introducing the concept of the quasiperiodic motion, we can explain the confused behaviour of the system as an intermediate state between periodic and chaotic motions. More specifically, we discuss the following two facts: (1) If we adjust the time interval Δt properly, figures consisting of plotted dots at the constant time interval acquire scale invariance under replacement of Δt by sΔt, where s(>1) is an arbitrary real but not transcendental number. (2) We can compute values of the time variable t, which let |Sz(t)| (the absolute value of the z-component of the Bloch vector) be very small, with the Diophantine approximation (a rational approximation of an irrational number).

KARAKTERISTIK BENTUK DAN UKURAN SEL DARAH IKAN BETOK (Anabas testudineus DAN IKAN GABUS (Chana sriata

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Hidayaturrahmah Hidayaturrahmah

2016-09-01

Full Text Available The study was conducted to assess the characteristics regarding the size and shape of blood cells climbing perch and striped snakehead. Samples obtained from martapura river districts banjar, South Kalimantan. Blood examination carried using hematology method. Results showed that the cells form erythrocytes on climbing perch is round, while the oval-shaped striped snakehead. The Form of leukocytes, platelets, lymphocytes, monocytes, neutrophils, eosinophils and basophils Both betok fish and gabus fish everything Shaped round. characteristics  of Blood cell climbing perch have red cell (eritrocyt size of 7.36 ± 0.65 x 106 µm; Platelet count of 3.59 ± 0.32 µm, lymphocytes 5.11 ± 1.02 µm, monocytes 7.76 ± 1.36 µm, Eosinophils 8.74 ± 0.47 µm, Bashophil 8:24 ± 0.33 µm. characteristics  size of blood cells striped snakehead are: erythrocytes 10.29 ± 0.33 µm, 3.59 ± 0.66 µm platelets, lymphocytes 6.85 ± 0.75 µm, monocytes 8.02 ± 0.41 µm, Eosinophils 7, 46 µm, Bashophil 9.63 ± 0.21 µm.

Taking a peek at Bloch oscillations

Science.gov (United States)

Morsch, Oliver

2016-11-01

Bloch oscillations arise when matter waves inside a periodic potential, such as a crystal lattice, are accelerated by a constant force. Keßler et al (2016 New J. Phys. 18 102001) have now experimentally tested a method that allows one to observe those oscillations continuously, without a destructive measurement on the matter wave. Their approach could help to make cold atom-based accelerometers and gravimeters more precise.

Incorporating excitation-induced dephasing into the Maxwell-Bloch numerical modeling of photon echoes

International Nuclear Information System (INIS)

Burr, G.W.; Harris, Todd L.; Babbitt, Wm. Randall; Jefferson, C. Michael

2004-01-01

We describe the incorporation of excitation-induced dephasing (EID) into the Maxwell-Bloch numerical simulation of photon echoes. At each time step of the usual numerical integration, stochastic frequency jumps of ions--caused by excitation of neighboring ions--is modeled by convolving each Bloch vector with the Bloch vectors of nearby frequency detunings. The width of this convolution kernel follows the instantaneous change in overall population, integrated over the simulated bandwidth. This approach is validated by extensive comparison against published and original experimental results. The enhanced numerical model is then used to investigate the accuracy of experiments designed to extrapolate to the intrinsic dephasing time T 2 from data taken in the presence of EID. Such a modeling capability offers improved understanding of experimental results, and should allow quantitative analysis of engineering tradeoffs in realistic optical coherent transient applications

Comprehensive solutions to the Bloch equations and dynamical models for open two-level systems

Science.gov (United States)

Skinner, Thomas E.

2018-01-01

The Bloch equation and its variants constitute the fundamental dynamical model for arbitrary two-level systems. Many important processes, including those in more complicated systems, can be modeled and understood through the two-level approximation. It is therefore of widespread relevance, especially as it relates to understanding dissipative processes in current cutting-edge applications of quantum mechanics. Although the Bloch equation has been the subject of considerable analysis in the 70 years since its inception, there is still, perhaps surprisingly, significant work that can be done. This paper extends the scope of previous analyses. It provides a framework for more fully understanding the dynamics of dissipative two-level systems. A solution is derived that is compact, tractable, and completely general, in contrast to previous results. Any solution of the Bloch equation depends on three roots of a cubic polynomial that are crucial to the time dependence of the system. The roots are typically only sketched out qualitatively, with no indication of their dependence on the physical parameters of the problem. Degenerate roots, which modify the solutions, have been ignored altogether. Here the roots are obtained explicitly in terms of a single real-valued root that is expressed as a simple function of the system parameters. For the conventional Bloch equation, a simple graphical representation of this root is presented that makes evident the explicit time dependence of the system for each point in the parameter space. Several intuitive, visual models of system dynamics are developed. A Euclidean coordinate system is identified in which any generalized Bloch equation is separable, i.e., the sum of commuting rotation and relaxation operators. The time evolution in this frame is simply a rotation followed by relaxation at modified rates that play a role similar to the standard longitudinal and transverse rates. These rates are functions of the applied field, which

Self-consistent Maxwell-Bloch theory of quantum-dot-population switching in photonic crystals

International Nuclear Information System (INIS)

Takeda, Hiroyuki; John, Sajeev

2011-01-01

We theoretically demonstrate the population switching of quantum dots (QD's), modeled as two-level atoms in idealized one-dimensional (1D) and two-dimensional (2D) photonic crystals (PC's) by self-consistent solution of the Maxwell-Bloch equations. In our semiclassical theory, energy states of the electron are quantized, and electron dynamics is described by the atomic Bloch equation, while electromagnetic waves satisfy the classical Maxwell equations. Near a waveguide cutoff in a photonic band gap, the local electromagnetic density of states (LDOS) and spontaneous emission rates exhibit abrupt changes with frequency, enabling large QD population inversion driven by both continuous and pulsed optical fields. We recapture and generalize this ultrafast population switching using the Maxwell-Bloch equations. Radiative emission from the QD is obtained directly from the surrounding PC geometry using finite-difference time-domain simulation of the electromagnetic field. The atomic Bloch equations provide a source term for the electromagnetic field. The total electromagnetic field, consisting of the external input and radiated field, drives the polarization components of the atomic Bloch vector. We also include a microscopic model for phonon dephasing of the atomic polarization and nonradiative decay caused by damped phonons. Our self-consistent theory captures stimulated emission and coherent feedback effects of the atomic Mollow sidebands, neglected in earlier treatments. This leads to remarkable high-contrast QD-population switching with relatively modest (factor of 10) jump discontinuities in the electromagnetic LDOS. Switching is demonstrated in three separate models of QD's placed (i) in the vicinity of a band edge of a 1D PC, (ii) near a cutoff frequency in a bimodal waveguide channel of a 2D PC, and (iii) in the vicinity of a localized defect mode side coupled to a single-mode waveguide channel in a 2D PC.

Optical Bloch equations with multiply connected states

International Nuclear Information System (INIS)

Stacey, D N; Lucas, D M; Allcock, D T C; Szwer, D J; Webster, S C

2008-01-01

The optical Bloch equations, which give the time evolution of the elements of the density matrix of an atomic system subject to radiation, are generalized so that they can be applied when transitions between pairs of states can proceed by more than one stimulated route. The case considered is that for which the time scale of interest in the problem is long compared with that set by the differences in detuning of the radiation fields stimulating via the different routes. It is shown that the Bloch equations then reduce to the standard form of linear differential equations with constant coefficients. The theory is applied to a two-state system driven by two lasers with different intensities and frequencies and to a three-state Λ-system with one laser driving one transition and two driving the second. It is also shown that the theory reproduces well the observed response of a cold 40 Ca + ion when subject to a single laser frequency driving the 4S 1/2 -4P 1/2 transition and a laser with two strong sidebands driving 3D 3/2 -4P 1/2

Designing non-Hermitian dynamics for conservative state evolution on the Bloch sphere

Science.gov (United States)

Yu, Sunkyu; Piao, Xianji; Park, Namkyoo

2018-03-01

An evolution on the Bloch sphere is the fundamental state transition, including optical polarization controls and qubit operations. Conventional evolution of a polarization state or qubit is implemented within a closed system that automatically satisfies energy conservation from the Hermitian formalism. Although particular forms of static non-Hermitian Hamiltonians, such as parity-time-symmetric Hamiltonians, allow conservative states in an open system, the criteria for the energy conservation in a dynamical open system have not been fully explored. Here, we derive the condition of conservative state evolution in open-system dynamics and its inverse design method, by developing the non-Hermitian modification of the Larmor precession equation. We show that the geometrically designed locus on the Bloch sphere can be realized by different forms of dynamics, leading to the isolocus family of non-Hermitian dynamics. This increased degree of freedom allows the complementary phenomena of error-robust and highly sensitive evolutions on the Bloch sphere, which could be applicable to stable polarizers, quantum gates, and optimized sensors in dynamical open systems.

Improved Reading Gate For Vertical-Bloch-Line Memory

Science.gov (United States)

Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.

1994-01-01

Improved design for reading gate of vertical-Bloch-line magnetic-bubble memory increases reliability of discrimination between binary ones and zeros. Magnetic bubbles that signify binary "1" and "0" produced by applying sufficiently large chopping currents to memory stripes. Bubbles then propagated differentially in bubble sorter. Method of discriminating between ones and zeros more reliable.

On averaging the Kubo-Hall conductivity of magnetic Bloch bands leading to Chern numbers

International Nuclear Information System (INIS)

Riess, J.

1997-01-01

The authors re-examine the topological approach to the integer quantum Hall effect in its original form where an average of the Kubo-Hall conductivity of a magnetic Bloch band has been considered. For the precise definition of this average it is crucial to make a sharp distinction between the discrete Bloch wave numbers k 1 , k 2 and the two continuous integration parameters α 1 , α 2 . The average over the parameter domain 0 ≤ α j 1 , k 2 . They show how this can be transformed into a single integral over the continuous magnetic Brillouin zone 0 ≤ α j j , j = 1, 2, n j = number of unit cells in j-direction, keeping k 1 , k 2 fixed. This average prescription for the Hall conductivity of a magnetic Bloch band is exactly the same as the one used for a many-body system in the presence of disorder

Quantum Transport in Solids: Bloch Dynamics and Role of Oscillating Fields

National Research Council Canada - National Science Library

Kim, Ki

1997-01-01

.... The specific areas of research are those of Bloch electron dynamics, quantum transport in oscillating electric fields or in periodic potentials, and the capacitive nature of atomic size structures...

Bloch-wave engineered submicron-diameter quantum-dot micropillars for cavity QED experiments

DEFF Research Database (Denmark)

Gregersen, Niels; Lermer, Matthias; Reitzenstein, Stephan

2013-01-01

The semiconductor micropillar is attractive for cavity QED experiments. For strong coupling, the figure of merit is proportional to Q/√V, and a design combining a high Q and a low mode volume V is thus desired. However, for the standard submicron diameter design, poor mode matching between the ca...... the cavity and the DBR Bloch mode limits the Q. We present a novel adiabatic design where Bloch-wave engineering is employed to improve the mode matching, allowing the demonstration of a record-high vacuum Rabi splitting of 85 μeV and a Q of 13600 for a 850 nm diameter micropillar....

PENGARUH FLUKTUASI TINGGI MUKA AIR TERHADAP HASIL TANGKAPAN IKAN DI SUNGAI DAN RAWA MAHAKAM HULU KALIMANTAN TIMUR

Directory of Open Access Journals (Sweden)

Kamaluddin Kasim

2015-12-01

Full Text Available Beberapa penelitian menyebutkan bahwa fluktuasi tinggi muka air (TMA dapat mempengaruhi hasil tangkapan ikan di perairan sungai dan rawa namun tidak terhadap semua jenis ikan.  Penelitian ini dilakukan dengan tujuan untuk mengetahui hasil tangkapan jenis ikan sungai dan rawa sungai Mahakam yang mendapat pengaruh fluktuasi TMA dan jenis ikan yang tidak mendapatkan pengaruh langsung oleh fluktuasi TMA. Data mengenai hasil tangkapan ikan yang berasal dari alat tangkap pancing dan jaring diperoleh melalui enumerator di Tempat Pendaratan Ikan (TPI Selili Kota Samarinda pada periode 2007-2012, sedangkan nilai rata-rata Tinggi Muka Air (TMA DAS Mahakam secara bulanan diperlukan sebagai salah satu faktor yang diduga berpengaruh terhadap hasil tangkapan beberapa jenis ikan sungai dan rawa. Data dianalisis dengan metode regresi linear sederhana dan penentuan perbedaan hasil tangkapan pada musim hujan, peralihan dan kemarau dilakukan dengan Analysis of Variance (ANOVA. Hasil penelitian menunjukkan bahwa jumlah hasil tangkapan ikan berkorelasi kuat (r=0,7 terhadap Tinggi Muka air (TMA dengan arah hubungan negatif atau berkebalikan, yakni semakin tinggi nilai TMA maka hasil tangkapan semakin rendah. Jenis ikan sungai dan rawa seperti patin, nila, sepat siam (Trichogaster pectoralis, lais dan betok (Anabas testudineus merupakan jenis ikan yang hasil tangkapannya dipengaruhi secara signifikan (P0,05 oleh fluktuasi TMA.   Some studies have showed that water level fluctuation may have a significant correlation to the catch of several commercial fish target in inland fishery and does not influence directly the cath of some commercial fish. This study aimed to determine which species are directly influenced and such species not inluenced by water level fluctuation for its catches. Catch data obtained from hand line and gill net are recorded by enumerators at Fish Landing Sites of Selili, Samarinda during the period of 2007-2012, while the data of surface water

On the equilibrium configuration of the Kittel type domain structure with Bloch walls, l80deg

International Nuclear Information System (INIS)

Gavrila, H.

1975-01-01

Using a phenomenologic method for appreciating different components of the free energy, the equilibrium configuration of the Kittel-type domain structure with Bloch walls is obtained. By improving the known methods, more accurate magnetostatic energy calculations are reported. In order to determine the equilibrium structure, the total free energy is minimized with respect to two system parameters: the Bloch wall width and the structure half-period. (author)

News Focus: NSF Director Erich Bloch Discusses Foundation's Problems, Outlook.

Science.gov (United States)

Chemical and Engineering News, 1987

1987-01-01

Relates the comments offered in an interview with Erich Bloch, the National Science Foundation (NSF) Director. Discusses issues related to NSF and its funding, engineering research centers, involvement with industry, concern for science education, computer centers, and its affiliation with the social sciences. (ML)

Influence of relaxation times on the Bloch-Siegert shift

International Nuclear Information System (INIS)

Cao Long Van

1981-01-01

A new method for calculations of Bloch-Siegert shifts in resonances between excited states with the inclusion of relaxation times is given. It will be shown that in this case the definition of the resonance given by I. Bialynicka-Birula is in agreement with the criterion defining the resonance used by D.A. Andrews and G. Newton. (author)

A 2D multi-term time and space fractional Bloch-Torrey model based on bilinear rectangular finite elements

Science.gov (United States)

Qin, Shanlin; Liu, Fawang; Turner, Ian W.

2018-03-01

The consideration of diffusion processes in magnetic resonance imaging (MRI) signal attenuation is classically described by the Bloch-Torrey equation. However, many recent works highlight the distinct deviation in MRI signal decay due to anomalous diffusion, which motivates the fractional order generalization of the Bloch-Torrey equation. In this work, we study the two-dimensional multi-term time and space fractional diffusion equation generalized from the time and space fractional Bloch-Torrey equation. By using the Galerkin finite element method with a structured mesh consisting of rectangular elements to discretize in space and the L1 approximation of the Caputo fractional derivative in time, a fully discrete numerical scheme is derived. A rigorous analysis of stability and error estimation is provided. Numerical experiments in the square and L-shaped domains are performed to give an insight into the efficiency and reliability of our method. Then the scheme is applied to solve the multi-term time and space fractional Bloch-Torrey equation, which shows that the extra time derivative terms impact the relaxation process.

Surface Acoustic Bloch Oscillations, the Wannier-Stark Ladder, and Landau-Zener Tunneling in a Solid

Science.gov (United States)

de Lima, M. M., Jr.; Kosevich, Yu. A.; Santos, P. V.; Cantarero, A.

2010-04-01

We present the experimental observation of Bloch oscillations, the Wannier-Stark ladder, and Landau-Zener tunneling of surface acoustic waves in perturbed grating structures on a solid substrate. A model providing a quantitative description of our experimental observations, including multiple Landau-Zener transitions of the anticrossed surface acoustic Wannier-Stark states, is developed. The use of a planar geometry for the realization of the Bloch oscillations and Landau-Zener tunneling allows a direct access to the elastic field distribution. The vertical surface displacement has been measured by interferometry.

Bloch Oscillations in the Chains of Artificial Atoms Dressed with Photons

Directory of Open Access Journals (Sweden)

Ilay Levie

2018-06-01

Full Text Available We present a model of one-dimensional chain of two-level artificial atoms driven with DC field and quantum light simultaneously in a strong coupling regime. The interaction of atoms with light leads to electron-photon entanglement (dressing of the atoms with light. The driving via dc field leads to the Bloch oscillations (BO in the chain of dressed atoms. We consider the mutual influence of dressing and BO and show that scenario of oscillations dramatically differs from predicted by the Jaynes-Cummings and Bloch-Zener models. We study the evolution of the population inversion, tunneling current, photon probability distribution, mean number of photons, and photon number variance, and show the influence of BO on the quantum-statistical characteristics of light. For example, the collapse-revivals picture and vacuum Rabi-oscillations are strongly modulated with Bloch frequency. As a result, quantum properties of light and degree of electron-photon entanglement become controllable via adiabatic dc field turning. On the other hand, the low-frequency tunneling current depends on the quantum light statistics (in particular, for coherent initial state it is modulated accordingly the collapse-revivals picture. The developed model is universal with respect to the physical origin of artificial atom and frequency range of atom-light interaction. The model is adapted to the 2D-heterostructures (THz frequencies, semiconductor quantum dots (optical range, and Josephson junctions (microwaves. The data for numerical simulations are taken from recently published experiments. The obtained results open a new way in quantum state engineering and nano-photonic spectroscopy.

An Optomechanical Elevator: Transport of a Bloch Oscillating Bose–Einstein Condensate up and down an Optical Lattice by Cavity Sideband Amplification and Cooling

Directory of Open Access Journals (Sweden)

B. Prasanna Venkatesh

2015-12-01

Full Text Available In this paper we give a new description, in terms of optomechanics, of previous work on the problem of an atomic Bose–Einstein condensate interacting with the optical lattice inside a laser-pumped optical cavity and subject to a bias force, such as gravity. An atomic wave packet in a tilted lattice undergoes Bloch oscillations; in a high-finesse optical cavity the backaction of the atoms on the light leads to a time-dependent modulation of the intracavity lattice depth at the Bloch frequency which can in turn transport the atoms up or down the lattice. In the optomechanical picture, the transport dynamics can be interpreted as a manifestation of dynamical backaction-induced sideband damping/amplification of the Bloch oscillator. Depending on the sign of the pump-cavity detuning, atoms are transported either with or against the bias force accompanied by an up- or down-conversion of the frequency of the pump laser light. We also evaluate the prospects for using the optomechanical Bloch oscillator to make continuous measurements of forces by reading out the Bloch frequency. In this context, we establish the significant result that the optical spring effect is absent and the Bloch frequency is not modified by the backaction.

New algorithm for efficient Bloch-waves calculations of orientation-sensitive ELNES

Czech Academy of Sciences Publication Activity Database

Rusz, Ján; Muto, S.; Tatsumi, K.

2013-01-01

Roč. 125, Feb (2013), s. 81-88 ISSN 0304-3991 Institutional support: RVO:68378271 Keywords : transmission electron microscopy * density functional theory * dynamical diffraction theory * Bloch waves * electron magnetic circular dichroism Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.745, year: 2013

Molecular Phylogenetics of Centrocestus formosanus (Digenea: Heterophyidae) Originated from Freshwater Fish from Chiang Mai Province, Thailand.

Science.gov (United States)

Wongsawad, Chalobol; Wongsawad, Pheravut; Sukontason, Kom; Maneepitaksanti, Worawit; Nantarat, Nattawadee

2017-02-01

This study aimed to investigate the morphology and reconstruct the phylogenetic relationships of Centrocestus formosanus originating from 5 species of freshwater fish, i.e., Esomus metallicus, Puntius brevis, Anabas testudineus, Parambassis siamensis , and Carassius auratus , in Chiang Mai province, Thailand. Sequence-related amplified polymorphism (SRAP) and phylogeny based on internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (CO1) were performed. The results showed similar morphologies of adult C. formosanus from day 5 after infection in chicks. C. formosanus originated from 4 species of freshwater fish had the same number of circumoral spines on the oral sucker, except for those from C. auratus which revealed 34 circumoral spines. The phylogenetic tree obtained from SRAP profile and the combination of ITS2 and CO1 sequence showed similar results that were correlated with the number of circumoral spines in adult worms. Genetic variability of C. formosanus also occurred in different species of freshwater fish hosts. However, more details of adult worm morphologies and more sensitive genetic markers are needed to confirm the species validity of C. formosanus with 34 circumoral spines originating from C. auratus in the future.

Evaluation of toxicity and translocation of Carbofuran in a simulated rice-fish ecosystem

International Nuclear Information System (INIS)

Sikder, M.Q.; Nabi, M.R.; AminUddin, M.; Rahman, M.S.

2005-01-01

Toxic effects of 14 C-carbofuran on climbing perch (Anabas testudineus), its translocation and residual accumulation in a rice-fish ecosystem under simulated conditions in an aquarium was studied. Mortality trial showed that carbofuran concentration of 4 ppm acutely toxic and kill the fish until the fifth day and after five days, residual concentration in water was not lethal to fish. Carbofuran was applied in the soil in glass aquarium planted with paddy at the rate of 0.75 kg a.i./ha. Maximum radioactivity was observed in water on day 1 (0.07 μg/l) and day 3 (0.07μg/l) after application of the pesticide. In soil sample radioactivity increased gradually and reached peak level of 1.134 μg/g on day 98 after pesticide application. In rice plants, the emergent portion was found highest level of 33.6 μg/g on day 71 and in the submerged portion it was 2.336 μg/g on the same day. Highest level of radioactivity was recorded in muscle tissue (0.252 μg/g) and visceral tissue of the fist (0.724 μg/g) on day 66 after carbofuran application.(author)

Integral-Type Operators from Bloch-Type Spaces to QK Spaces

Directory of Open Access Journals (Sweden)

Stevo Stević

2011-01-01

Full Text Available The boundedness and compactness of the integral-type operator Iφ,g(nf(z=∫0zf(n(φ(ζg(ζdζ, where n∈N0, φ is a holomorphic self-map of the unit disk D, and g is a holomorphic function on D, from α-Bloch spaces to QK spaces are characterized.

Surface Acoustic Analog of Bloch Oscillations, Wannier-Stark Ladders and Landau-Zener Tunneling

Science.gov (United States)

de Lima, M. M.; Kosevich, Yu. A.; Santos, P. V.; Cantarero, A.

2011-12-01

In this contribution, we discuss the recent experimental demonstration of Wannier-Stark ladders, Bloch Oscillations and Landau Zener tunneling in a solid by means of surface acoustic waves propagating through perturbed grating structures.

Hábitos alimenticios de Sphoeroides testudineus (Perciformes: Tetraodontidae en el sistema lagunar de Ría Lagartos, Yucatán, México

Directory of Open Access Journals (Sweden)

Ariel Adriano Chi-Espínola

2013-06-01

Full Text Available Sphoeroides testudineus, es una especie dominante en los sistemas costeros de Yucatán. Debido a su amplia distribución, ocurrencia y abundancia realiza un importante papel funcional en los ecosistemas costeros. Evaluamos para esta especie las preferencias tróficas y su variación a nivel espacial y temporal en la laguna de Ría Lagartos, un ecosistema hiperhalino localizado al noroeste de la península de Yucatán. Los especímenes fueron recolectados bimensualmente durante dos periodos anuales (2004-2005 y 2007-2008 en 23 sitios distribuidos a lo largo del sistema en cuatro zonas (marina, canal, Coloradas oeste y Coloradas este. Las variaciones tróficas espaciales y temporales fueron evaluadas mediante un análisis de correspondencia canónica (ACC. En un total de 382 individuos, se obtuvieron 68 recursos alimenticios incluidos en 20 grupos tróficos. El mayor índice de importancia relativa (IIR lo obtuvieron los bivalvos, gasterópodos y macrófitas. La variación trófica estacional mostró que los bivalvos y gasterópodos son consumidos a lo largo del año, mientras que las macrófitas constituyeron el alimento preferencial en la temporada de lluvias y nortes. La variación espacial indica un bajo consumo de gasterópodos hacia el interior de la laguna, y lo opuesto sucedió con los bivalvos. El consumo de macrófitas pudo ser debido a su mayor abundancia durante lluvias y en la zona del canal. El ACC mostró que la variación trófica espacial se debió a la abundancia de las presas preferenciales (bivalvos y gasterópodos, mientras que las diferencias estacionales por las presas secundarias (anfípodos, huevos, nematodos, braquiuros, detritus, nemátodos. Los resultados contribuyen al conocimiento biológico de la especie y resaltan la importancia y función trófica de Sphoeroides testudineus en las transferencias de energía desde el bentos hacia los niveles tróficos superiores de la cadena alimenticia.

General PFG signal attenuation expressions for anisotropic anomalous diffusion by modified-Bloch equations

Science.gov (United States)

Lin, Guoxing

2018-05-01

Anomalous diffusion exists widely in polymer and biological systems. Pulsed-field gradient (PFG) anomalous diffusion is complicated, especially in the anisotropic case where limited research has been reported. A general PFG signal attenuation expression, including the finite gradient pulse (FGPW) effect for free general anisotropic fractional diffusion { 0 integral modified-Bloch equation, were extended to obtain general PFG signal attenuation expressions for anisotropic anomalous diffusion. Various cases of PFG anisotropic anomalous diffusion were investigated, including coupled and uncoupled anisotropic anomalous diffusion. The continuous-time random walk (CTRW) simulation was also carried out to support the theoretical results. The theory and the CTRW simulation agree with each other. The obtained signal attenuation expressions and the three-dimensional fractional modified-Bloch equations are important for analyzing PFG anisotropic anomalous diffusion in NMR and MRI.

Integrative assessment of biomarker responses in teleostean fishes exposed to glyphosate-based herbicide (Excel Mera 71

Directory of Open Access Journals (Sweden)

Sukhendu Dey

2016-12-01

Full Text Available Present study deals with the effects of glyphosate-based herbicide, Excel Mera 71 on Anabas testudineus, Heteropnestes fossilis and Oreochromis niloticus in field conditions (1.85 kg/ha based on anti-oxidative, metabolic and digestive responses. For this study following biomarkers viz., acetylcholinesterase (AChE, lipid peroxidation (LPO, catalase (CAT, glutathione-S-transferase (GST, alkaline phosphatase (ALP, aspartate aminotransferase (AST, alanine aminotransferase (ALT, amylase, lipase and protease were investigated in gill, stomach, intestine, liver, kidney, brain, muscle and spinal cord of the concerned fish species. Enzyme activities were significantly altered by glyphosate exposure after 30 days, these activities were tissue as well as species specific. The results suggested that these biomarkers could be used to assess the ecological risks of glyphosate on fish. Bioaccumulation factor (BAF studied in different aquatic natural macrophytes showed order of Alternanthera philoxeroides > Azolla pinnata > Lemna sp. (Minor > Lemna sp. (Major > Pistia stratiotes, while transfer factor (TF showed the order of Pistia stratiotes > Alternanthera philoxeroides > Lemna sp. Bioconcentration factor (BCF study showed maximum accumulation of glyphosate in liver, kidney or intestine, and minimum either in bone or stomach irrespective of fish species. An integrated biomarker response (IBR, which uses a battery of biomarkers to calculate the standardized scores for each biomarker responses ranging from physiological to biochemical/molecular responses, was evaluated by combining the multiple biomarkers into a single value to evaluate quantitatively the toxicological effects of glyphosate. In general, the multiple indices exhibited variations and A. testudineus was more affected than other fish species; maximum IBR value was observed for LPO and minimum in case of ALT. The order of integrated biomarkers caused by glyphosate treatment was

Bloch-Kohn and Wannier-Kohn functions in one dimension

International Nuclear Information System (INIS)

Bruno-Alfonso, Alexys; Guo-Qiang, Hai

2003-01-01

Bloch and Wannier functions of the Kohn type for a quite general one-dimensional Hamiltonian with inversion symmetry are studied. Important clarifications on null minigaps and the symmetry of those functions are given, with emphasis on the Kronig-Penney model. The lack of a general selection rule on the miniband index for optical transitions between edge states in semiconductor superlattices is discussed. A direct method for the calculation of Wannier-Kohn functions is presented

A new characterization of Bloch function in the unit ball of Cn

International Nuclear Information System (INIS)

Shi Jihuai.

1989-07-01

Bloch function in the unit disc v has many different but equivalent characterizations. Recently, a new characterization has been obtained by the study of Hankel operators. The purpose of this note is to generalize this characterization to the unit ball of C n . 7 refs

Traffic restrictions on Routes Bloch, Maxwell and Bohr

CERN Multimedia

IT Department

2008-01-01

Excavation and pipework is being carried out in the framework of the transfer of the waste water treatment plant for the effluents from the surface treatment workshops from Building 254 to Building 676, currently under construction. This work may encroach onto Routes Bloch, Maxwell and Bohr and disrupt the flow of traffic. Users are requested to comply with the road signs that will be erected. The work is expected to last until the beginning of December 2008. Thank you for your understanding. TS/CE and TS/FM Groups Tel.7 4188 or 16 4314

Diagrammatical display of the counter-example to non-Abelian Bloch-Nordsieck conjecture

International Nuclear Information System (INIS)

Yoshida, Nobuo

1981-01-01

The reason why the Bloch-Nordsieck theorem breaks down in the Drell-Yan process is shown through a simple diagrammatical calculation. The uncancelled contribution is from the retarded soft gluons, and the colour weight different for each ''double cut diagram'' interrupts the cancellation analogous to QED. (author)

Bloch Surface Waves Using Graphene Layers: An Approach toward In-Plane Photodetectors

Directory of Open Access Journals (Sweden)

Richa Dubey

2018-03-01

Full Text Available A dielectric multilayer platform was investigated as a foundation for two-dimensional optics. In this paper, we present, to the best of our knowledge, the first experimental demonstration of absorption of Bloch surface waves in the presence of graphene layers. Graphene is initially grown on a Cu foil via Chemical Vapor Deposition and transferred layer by layer by a wet-transfer method using poly(methyl methacrylate, (PMMA. We exploit total internal reflection configuration and multi-heterodyne scanning near-field optical microscopy as a far-field coupling method and near-field characterization tool, respectively. The absorption is quantified in terms of propagation lengths of Bloch surface waves. A significant drop in the propagation length of the BSWs is observed in the presence of graphene layers. The propagation length of BSWs in bare multilayer is reduced to 17 times shorter in presence of graphene monolayer, and 23 times shorter for graphene bilayer.

On an Integral-Type Operator Acting between Bloch-Type Spaces on the Unit Ball

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Stevo Stević

2010-01-01

Full Text Available Let 𝔹 denote the open unit ball of ℂn. For a holomorphic self-map φ of 𝔹 and a holomorphic function g in 𝔹 with g(0=0, we define the following integral-type operator: Iφgf(z=∫01ℜf(φ(tzg(tz(dt/t, z∈𝔹. Here ℜf denotes the radial derivative of a holomorphic function f in 𝔹. We study the boundedness and compactness of the operator between Bloch-type spaces ℬω and ℬμ, where ω is a normal weight function and μ is a weight function. Also we consider the operator between the little Bloch-type spaces ℬω,0 and ℬμ,0.

Optimal cloning of qubits given by an arbitrary axisymmetric distribution on the Bloch sphere

International Nuclear Information System (INIS)

Bartkiewicz, Karol; Miranowicz, Adam

2010-01-01

We find an optimal quantum cloning machine, which clones qubits of arbitrary symmetrical distribution around the Bloch vector with the highest fidelity. The process is referred to as phase-independent cloning in contrast to the standard phase-covariant cloning for which an input qubit state is a priori better known. We assume that the information about the input state is encoded in an arbitrary axisymmetric distribution (phase function) on the Bloch sphere of the cloned qubits. We find analytical expressions describing the optimal cloning transformation and fidelity of the clones. As an illustration, we analyze cloning of qubit state described by the von Mises-Fisher and Brosseau distributions. Moreover, we show that the optimal phase-independent cloning machine can be implemented by modifying the mirror phase-covariant cloning machine for which quantum circuits are known.

Quantum Theory of Conducting Matter Newtonian Equations of Motion for a Bloch Electron

CERN Document Server

Fujita, Shigeji

2007-01-01

Quantum Theory of Conducting Matter: Newtonian Equations of Motion for a Bloch Electron targets scientists, researchers and graduate-level students focused on experimentation in the fields of physics, chemistry, electrical engineering, and material sciences. It is important that the reader have an understanding of dynamics, quantum mechanics, thermodynamics, statistical mechanics, electromagnetism and solid-state physics. Many worked-out problems are included in the book to aid the reader's comprehension of the subject. The Bloch electron (wave packet) moves by following the Newtonian equation of motion. Under an applied magnetic field B the electron circulates around the field B counterclockwise or clockwise depending on the curvature of the Fermi surface. The signs of the Hall coefficient and the Seebeck coefficient are known to give the sign of the major carrier charge. For alkali metals, both are negative, indicating that the carriers are "electrons." These features arise from the Fermi surface difference...

Bipolaron assisted Bloch-like oscillations in organic lattices

International Nuclear Information System (INIS)

Ribeiro, Luiz Antonio; Ferreira da Cunha, Wiliam; Magela e Silva, Geraldo

2017-01-01

The transport of a dissociated bipolaron in organic one-dimensional lattices is theoretically investigated in the scope of a tight-binding model that includes electron-lattice interactions and an external electric field. Remarkably, the results point to a physical picture in which the dissociated bipolaron propagates as a combined state of two free-like electrons that coherently perform spatial Bloch oscillations (BO) above a critical field strength. It was also obtained that the BO's trajectory presents a net forward motion in the direction of the applied electric field. The impact of dynamical disorder in the formation of electronic BOs is determined.

Bipolaron assisted Bloch-like oscillations in organic lattices

Science.gov (United States)

Ribeiro, Luiz Antonio; Ferreira da Cunha, Wiliam; Magela e Silva, Geraldo

2017-06-01

The transport of a dissociated bipolaron in organic one-dimensional lattices is theoretically investigated in the scope of a tight-binding model that includes electron-lattice interactions and an external electric field. Remarkably, the results point to a physical picture in which the dissociated bipolaron propagates as a combined state of two free-like electrons that coherently perform spatial Bloch oscillations (BO) above a critical field strength. It was also obtained that the BO's trajectory presents a net forward motion in the direction of the applied electric field. The impact of dynamical disorder in the formation of electronic BOs is determined.

Bipolaron assisted Bloch-like oscillations in organic lattices

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Luiz Antonio, E-mail: ribeirojr@unb.br [International Center for Condensed Matter Physics, University of Brasília, P.O. Box 04531, 70.919-970, Brasília, DF (Brazil); University of Brasília, UnB Faculty of Planaltina, 73.345-010, Planaltina, DF (Brazil); Ferreira da Cunha, Wiliam; Magela e Silva, Geraldo [Institute of Physics, University of Brasília, 70.919-970, Brasília (Brazil)

2017-06-15

The transport of a dissociated bipolaron in organic one-dimensional lattices is theoretically investigated in the scope of a tight-binding model that includes electron-lattice interactions and an external electric field. Remarkably, the results point to a physical picture in which the dissociated bipolaron propagates as a combined state of two free-like electrons that coherently perform spatial Bloch oscillations (BO) above a critical field strength. It was also obtained that the BO's trajectory presents a net forward motion in the direction of the applied electric field. The impact of dynamical disorder in the formation of electronic BOs is determined.

Direct Observation of Bloch Harmonics and Negative Phase Velocity in Photonic Crystal Waveguides

NARCIS (Netherlands)

Gersen, H.; Karle, T.J.; Engelen, R.J.P.; Engelen, R.J.P.; Bogaerts, W.; Korterik, Jeroen P.; van Hulst, N.F.; Krauss, T.F.; Kuipers, L.

2005-01-01

The eigenfield distribution and the band structure of a photonic crystal waveguide have been measured with a phase-sensitive near-field scanning optical microscope. Bloch modes, which consist of more than one spatial frequency, are visualized in the waveguide. In the band structure, multiple

Matter-wave solitons and finite-amplitude Bloch waves in optical lattices with spatially modulated nonlinearity

Science.gov (United States)

Zhang, Jie-Fang; Li, Yi-Shen; Meng, Jianping; Wu, Lei; Malomed, Boris A.

2010-09-01

We investigate solitons and nonlinear Bloch waves in Bose-Einstein condensates trapped in optical lattices (OLs). By introducing specially designed localized profiles of the spatial modulation of the attractive nonlinearity, we construct an infinite set of exact soliton solutions in terms of Mathieu and elliptic functions, with the chemical potential belonging to the semi-infinite gap of the OL-induced spectrum. Starting from the particular exact solutions, we employ the relaxation method to construct generic families of soliton solutions in a numerical form. The stability of the solitons is investigated through the computation of the eigenvalues for small perturbations, and also by direct simulations. Finally, we demonstrate a virtually exact (in the numerical sense) composition relation between nonlinear Bloch waves and solitons.

Matter-wave solitons and finite-amplitude Bloch waves in optical lattices with spatially modulated nonlinearity

International Nuclear Information System (INIS)

Zhang Jiefang; Meng Jianping; Wu Lei; Li Yishen; Malomed, Boris A.

2010-01-01

We investigate solitons and nonlinear Bloch waves in Bose-Einstein condensates trapped in optical lattices (OLs). By introducing specially designed localized profiles of the spatial modulation of the attractive nonlinearity, we construct an infinite set of exact soliton solutions in terms of Mathieu and elliptic functions, with the chemical potential belonging to the semi-infinite gap of the OL-induced spectrum. Starting from the particular exact solutions, we employ the relaxation method to construct generic families of soliton solutions in a numerical form. The stability of the solitons is investigated through the computation of the eigenvalues for small perturbations, and also by direct simulations. Finally, we demonstrate a virtually exact (in the numerical sense) composition relation between nonlinear Bloch waves and solitons.

Effective Hamiltonians, two level systems, and generalized Maxwell-Bloch equations

International Nuclear Information System (INIS)

Sczaniecki, L.

1981-02-01

A new method is proposed involving a canonical transformation leading to the non-secular part of time-independent perturbation calculus. The method is used to derive expressions for effective Shen-Walls Hamiltonians which, taken in the two-level approximation and on the inclusion of non-Hamiltonian terms into the dynamics of the system, lead to generalized Maxwell-Bloch equations. The rotating wave approximation is written anew within the framework of our formalism. (author)

Modeling Dzyaloshinskii-Moriya Interaction at Transition Metal Interfaces: Constrained Moment versus Generalized Bloch Theorem

KAUST Repository

Dong, Yao-Jun

2017-10-29

Dzyaloshinskii-Moriya interaction (DMI) at Pt/Co interfaces is investigated theoretically using two different first principles methods. The first one uses the constrained moment method to build a spin spiral in real space, while the second method uses the generalized Bloch theorem approach to construct a spin spiral in reciprocal space. We show that although the two methods produce an overall similar total DMI energy, the dependence of DMI as a function of the spin spiral wavelength is dramatically different. We suggest that long-range magnetic interactions, that determine itinerant magnetism in transition metals, are responsible for this discrepancy. We conclude that the generalized Bloch theorem approach is more adapted to model DMI in transition metal systems, where magnetism is delocalized, while the constrained moment approach is mostly applicable to weak or insulating magnets, where magnetism is localized.

Modeling Dzyaloshinskii-Moriya Interaction at Transition Metal Interfaces: Constrained Moment versus Generalized Bloch Theorem

KAUST Repository

Dong, Yao-Jun; Belabbes, Abderrezak; Manchon, Aurelien

2017-01-01

Dzyaloshinskii-Moriya interaction (DMI) at Pt/Co interfaces is investigated theoretically using two different first principles methods. The first one uses the constrained moment method to build a spin spiral in real space, while the second method uses the generalized Bloch theorem approach to construct a spin spiral in reciprocal space. We show that although the two methods produce an overall similar total DMI energy, the dependence of DMI as a function of the spin spiral wavelength is dramatically different. We suggest that long-range magnetic interactions, that determine itinerant magnetism in transition metals, are responsible for this discrepancy. We conclude that the generalized Bloch theorem approach is more adapted to model DMI in transition metal systems, where magnetism is delocalized, while the constrained moment approach is mostly applicable to weak or insulating magnets, where magnetism is localized.

The Bloch wave operator: generalizations and applications: Part I. The time-independent case

CERN Document Server

Killingbeck, J P

2003-01-01

This is part 1 of a two-part review on wave operator theory and methods. The basic theory of the time-independent wave operator is presented in terms of partitioned matrix theory for the benefit of general readers, with a discussion of the links between the matrix and projection operator approaches. The matrix approach is shown to lead to simple derivations of the wave operators and effective Hamiltonians of Loewdin, Bloch, Des Cloizeaux and Kato as well as to some associated variational forms. The principal approach used throughout stresses the solution of the nonlinear equation for the reduced wave operator, leading to the construction of the effective Hamiltonians of Bloch and of Des Cloizeaux. Several mathematical techniques which are useful in implementing this approach are explained, some of them being relatively little known in the area of wave operator calculations. The theoretical discussion is accompanied by several specimen numerical calculations which apply the described techniques to a selection ...

Nonlinear Bloch waves in metallic photonic band-gap filaments

International Nuclear Information System (INIS)

Kaso, Artan; John, Sajeev

2007-01-01

We demonstrate the occurrence of nonlinear Bloch waves in metallic photonic crystals (PCs). These periodically structured filaments are characterized by an isolated optical pass band below an effective plasma gap. The pass band occurs in a frequency range where the metallic filament exhibits a negative, frequency-dependent dielectric function and absorption loss. The metallic losses are counterbalanced by gain in two models of inhomogeneously broadened nonlinear oscillators. In the first model, we consider close-packed quantum dots that fill the void regions of a two-dimensional (2D) metallic PC, and whose inhomogeneously broadened emission spectrum spans the original optical pass band of the bare filament. In the second model, we consider thin (10-50 nm) layers of inhomogeneously broadened two-level resonators, with large dipole oscillator strength, that cover the interior surfaces of 2D metallic (silver and tungsten) PCs. These may arise from localized surface plasmon resonances due to small metal particles or an otherwise rough metal surface. For simplicity, we treat electromagnetic modes with electric field perpendicular to the plane of metal periodicity. In both models, a pumping threshold of the resonators is found, above which periodic nonlinear solutions of Maxwell's equations with purely real frequency within the optical pass band emerge. These nonlinear Bloch waves exhibit a laserlike input pumping to output amplitude characteristic. For strong surface resonances, these nonlinear waves may play a role in light emission from a hot tungsten (suitably microstructured) filament

Nonlinear Bloch waves in metallic photonic band-gap filaments

Science.gov (United States)

Kaso, Artan; John, Sajeev

2007-11-01

We demonstrate the occurrence of nonlinear Bloch waves in metallic photonic crystals (PCs). These periodically structured filaments are characterized by an isolated optical pass band below an effective plasma gap. The pass band occurs in a frequency range where the metallic filament exhibits a negative, frequency-dependent dielectric function and absorption loss. The metallic losses are counterbalanced by gain in two models of inhomogeneously broadened nonlinear oscillators. In the first model, we consider close-packed quantum dots that fill the void regions of a two-dimensional (2D) metallic PC, and whose inhomogeneously broadened emission spectrum spans the original optical pass band of the bare filament. In the second model, we consider thin (10 50 nm) layers of inhomogeneously broadened two-level resonators, with large dipole oscillator strength, that cover the interior surfaces of 2D metallic (silver and tungsten) PCs. These may arise from localized surface plasmon resonances due to small metal particles or an otherwise rough metal surface. For simplicity, we treat electromagnetic modes with electric field perpendicular to the plane of metal periodicity. In both models, a pumping threshold of the resonators is found, above which periodic nonlinear solutions of Maxwell’s equations with purely real frequency within the optical pass band emerge. These nonlinear Bloch waves exhibit a laserlike input pumping to output amplitude characteristic. For strong surface resonances, these nonlinear waves may play a role in light emission from a hot tungsten (suitably microstructured) filament.

Quasi-periodic Schroedinger operators in one dimension, absolutely continuous spectra, Bloch waves, and integrable Hamiltonian systems

International Nuclear Information System (INIS)

Chierchia, L.

1986-01-01

In the first chapter, the eigenvalue problem for a periodic Schroedinger operator, Lf = (-d 2 /dx 2 + v)f = Ef, is viewed as a two-dimensional Hamiltonian system which is integrable in the sense of Arnold and Liouville. With the aid of the Floquet-BLoch theory, it is shown that such a system is conjugate to two harmonic oscillators with frequencies α and omega, being the rotation number for L and 2π/omega the period of the potential v. This picture is generalized in the second chapter, to quasi periodic Schroedinger operators, L/sub epsilon/, with highly irrational frequencies (omega 1 , ..., omega/sub d/), which are a small perturbation of periodic operators. In the last chapter, the absolutely continuous spectrum σ/sub ac/ of a general quasi-periodic Schroedinger operators is considered. The Radon-Nikodym derivatives (with respect to Lebesgue measure) of the spectral measures are computed in terms of special independent eigensolutions existing for almost ever E in σ/sub ac/. Finally, it is shown that weak Bloch waves always exist for almost ever E in σ/sub ac/ and the question of the existence of genuine Bloch waves is turned into a regularity problem for a certain nonlinear partial differential equation on a d-dimensional torus

Chaos synchronization in bi-axial magnets modeled by Bloch equation

International Nuclear Information System (INIS)

Moukam Kakmeni, F.M.; Nguenang, J.P.; Kofane, T.C.

2005-10-01

In this paper, we show that the bi-axial magnetic material modelled by Bloch equation admits chaotic solutions for a certain set of numerical values assigned to the system of parameters and initial conditions. Using the unidirectional linear and nonlinear feedback schemes, we demonstrate that two such systems can be synchronized together. The chaotic synchronization is discussed in the context of complete synchronization which means that the difference of the states of two relevant systems converge to zero. (author)

The acute toxicity of the metaldehyde on the climbing perch

Science.gov (United States)

Wahida Mohamad Ismail, Syamimi; Aini Dahalan, Farrah; Zakaria, Ammar; Mad Shakaff, Ali Yeon; Aqlima Ahmad, Siti; Shukor, Mohd Yunus Abd; Khalizan Sabullah, Mohd; Khalil, Khalilah Abdul; Jalil, Mohd Faizal Ab

2018-03-01

In Asia, Climbing perch (Anabas testudineus) is commonly found in paddy fields and irrigation systems. Due to its habitat, Climbing perch is exposed to toxic pesticides used in paddy fields such as metaldehyde which is one of the most widely used molluscicide. This study aims to determine the acute toxicity Lethal Concentration50 (LC50) of metaldehyde and its effect on the behaviour and physical changes of the Climbing perch. The fish mortality responses to six different metaldehyde concentrations ranging from 180 to 330 mg/L were investigated. The 96-h LC50 values were determined and analysed using three different analysis methods which is arithmetic, logarithmic and probit graphic. The LC50 values obtained in this study were 239, 234 and 232 mg/L, respectively. After 96-h of exposure to metaldehyde, the fish showed a series of abnormal behavioural response in all cases: imbalance position, and restlessness of movement. The LC50 values show that metaldehyde is moderately toxic to the Climbing perch indicating that metaldehyde is not destructive to Climbing perch. However, long term exposure of aquatic organisms to the metaldehyde means a continuous health risk for the fish population as they are more vulnerable and it is on high risk for human to consume this toxicated fishes.

Bacterial Diversity in the Digestive Tracts of Four Indian Air-Breathing Fish Species Investigated by PCR Based Denaturing Gradient Gel Electrophoresis

Directory of Open Access Journals (Sweden)

Suxu He

Full Text Available ABSTRACT An investigation was conducted to identify the allochthonous microbiota (entire intestine and the autochthonous microbiota in proximal intestine (PI and distal intestine (DI of four species of Indian air-breathing fish (climbing perch; Anabas testudineus, murrel; Channa punctatus, walking catfish; Clarias batrachus and stinging catfish; Heteropneustes fossilis by PCR based denaturing gradient gel electrophoresis (DGGE. High similarities of the allochthonous microbiota were observed between climbing perch and murrel, walking catfish and stinging catfish, indicating similar food behavior. The autochthonous microbiota of PI and DI from climbing perch and murrel revealed more similarity, than the result obtained from walking catfish and stinging catfish. The autochthonous microbiota of climbing perch and murrel were similar with regard to the allochthonous microbiota, but no such similarity was observed in case of walking catfish and stinging catfish. The fish genotype and intestinal bacteria are well matched and show co-evolutionary relationship. Three fish species has its unique bacteria; autochthonous Enterobacter cloacae, Edwardsiella tarda and Sphingobium sp. in DI of climbing perch, Pseudomonas sp.; allochthonous and autochthonous in PI of walking catfish and uncultured bacterium (EU697160.1, uncultured bacterium (JF018065.1 and uncultured bacterium (EU697160.1 for stinging catfish. In murrel, no unique bacteria were detected.

DHA and EPA Content and Fatty Acid Profile of 39 Food Fishes from India

Directory of Open Access Journals (Sweden)

Bimal Prasanna Mohanty

2016-01-01

Full Text Available Docosahexaenoic acid (DHA is the principal constituent of a variety of cells especially the brain neurons and retinal cells and plays important role in fetal brain development, development of motor skills, and visual acuity in infants, lipid metabolism, and cognitive support and along with eicosapentaenoic acid (EPA it plays important role in preventing atherosclerosis, dementia, rheumatoid arthritis, Alzheimer’s disease, and so forth. Being an essential nutrient, it is to be obtained through diet and therefore searching for affordable sources of these ω-3 polyunsaturated fatty acids (PUFA is important for consumer guidance and dietary counseling. Fish is an important source of PUFA and has unique advantage that there are many food fish species available and consumers have a wide choice owing to availability and affordability. The Indian subcontinent harbors a rich fish biodiversity which markedly varies in their nutrient composition. Here we report the DHA and EPA content and fatty acid profile of 39 important food fishes (including finfishes, shellfishes, and edible molluscs from both marine water and freshwater from India. The study showed that fishes Tenualosa ilisha, Sardinella longiceps, Nemipterus japonicus, and Anabas testudineus are rich sources of DHA and EPA. Promotion of these species as DHA rich species would enhance their utility in public health nutrition.

Properties of solutions of Bloch-type equations for the paraelectric phase of KDP

Energy Technology Data Exchange (ETDEWEB)

Glowacki, M; Paszkiewicz, T [Wroclaw Univ. (Poland). Inst. Fyziki Teoretycznej

1979-10-01

Exact solutions for two sets of Bloch-like equations describing the paraelectric phase of the model of KDP were studied. The general properties of both solutions are the same. However, in numerical calculations they differ significantly. A modification of the decay law connected with the soft mode frequency fluctuations is considered.

Simulation of NMR signals through the Bloch equations; Simulação de sinais de RMN através das equações de Bloch

Energy Technology Data Exchange (ETDEWEB)

Moraes, Tiago Bueno, E-mail: tiagobuemoraes@gmail.com [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Física; Colnago, Luiz Alberto, E-mail: tiagobuemoraes@gmail.com [Embrapa Instrumentação, São Carlos, SP (Brazil)

2014-07-01

The aim of this paper was to present a simple and fast way of simulating Nuclear Magnetic Resonance signals using the Bloch equations. These phenomenological equations describe the classical behavior of macroscopic magnetization and are easily simulated using rotation matrices. Many NMR pulse sequences can be simulated with this formalism, allowing a quantitative description of the influence of many experimental parameters. Finally, the paper presents simulations of conventional sequences such as Single Pulse, Inversion Recovery, Spin Echo and CPMG. (author)

Magnon localization and Bloch oscillations in finite Heisenberg spin chains in an inhomogeneous magnetic field.

Science.gov (United States)

Kosevich, Yuriy A; Gann, Vladimir V

2013-06-19

We study the localization of magnon states in finite defect-free Heisenberg spin-1/2 ferromagnetic chains placed in an inhomogeneous magnetic field with a constant spatial gradient. Continuous transformation from the extended magnon states to the localized Wannier-Zeeman states in a finite spin chain placed in an inhomogeneous field is described both analytically and numerically. We describe for the first time the non-monotonic dependence of the energy levels of magnons, both long and short wavelength, on the magnetic field gradient, which is a consequence of magnon localization in a finite spin chain. We show that, in contrast to the destruction of the magnon band and the establishment of the Wannier-Stark ladder in a vanishingly small field gradient in an infinite chain, the localization of magnon states at the chain ends preserves the memory of the magnon band. Essentially, the localization at the lower- or higher-field chain end resembles the localization of the positive- or negative-effective-mass band quasiparticles. We also show how the beat dynamics of coherent superposition of extended spin waves in a finite chain in a homogeneous or weakly inhomogeneous field transforms into magnon Bloch oscillations of the superposition of localized Wannier-Zeeman states in a strongly inhomogeneous field. We provide a semiclassical description of the magnon Bloch oscillations and show that the correspondence between the quantum and semiclassical descriptions is most accurate for Bloch oscillations of the magnon coherent states, which are built from a coherent superposition of a large number of the nearest-neighbour Wannier-Zeeman states.

Magnon localization and Bloch oscillations in finite Heisenberg spin chains in an inhomogeneous magnetic field

International Nuclear Information System (INIS)

Kosevich, Yuriy A; Gann, Vladimir V

2013-01-01

We study the localization of magnon states in finite defect-free Heisenberg spin-1/2 ferromagnetic chains placed in an inhomogeneous magnetic field with a constant spatial gradient. Continuous transformation from the extended magnon states to the localized Wannier–Zeeman states in a finite spin chain placed in an inhomogeneous field is described both analytically and numerically. We describe for the first time the non-monotonic dependence of the energy levels of magnons, both long and short wavelength, on the magnetic field gradient, which is a consequence of magnon localization in a finite spin chain. We show that, in contrast to the destruction of the magnon band and the establishment of the Wannier–Stark ladder in a vanishingly small field gradient in an infinite chain, the localization of magnon states at the chain ends preserves the memory of the magnon band. Essentially, the localization at the lower- or higher-field chain end resembles the localization of the positive- or negative-effective-mass band quasiparticles. We also show how the beat dynamics of coherent superposition of extended spin waves in a finite chain in a homogeneous or weakly inhomogeneous field transforms into magnon Bloch oscillations of the superposition of localized Wannier–Zeeman states in a strongly inhomogeneous field. We provide a semiclassical description of the magnon Bloch oscillations and show that the correspondence between the quantum and semiclassical descriptions is most accurate for Bloch oscillations of the magnon coherent states, which are built from a coherent superposition of a large number of the nearest-neighbour Wannier–Zeeman states. (paper)

The annihilation of vertical-Bloch lines in the walls of hard domains to which bias fields and in-plane fields are alternately applied

International Nuclear Information System (INIS)

Sun, H.Y.; Hu, H.N.; Nie, X.F.

2001-01-01

The annihilation of vertical-Bloch lines in magnetic domain walls of the ordinary hard bubbles, to which both bias fields and in-plane fields are alternately applied, is investigated experimentally. The influence of an in-plane magnetic field on ordinary hard bubbles (OHB), dumbbell domains of the first kind (ID), and dumbbell domains of the second kind (IID) was analyzed, and a critical in-plane field range [H ip 0 ,H ip 2 ] for vertical Bloch line (VBL) annihilation was found. For the three types of hard domains (H ip 0 is the minimum critical in-plane field of VBLs which begin to be unstable, H ip 2 is the minimum critical in-plane field which only needs to be applied one time for collapse of all OHBs), the critical field range is the same with H ip 0 ≅8πM s . We hypothesize that there exists a direction along which the vertical-Bloch lines in the domain walls are annihilated most easily. It is also observed that the stability of vertical-Bloch lines in the domain walls does not depend on the initial state. This provides a more detailed description of the minimum critical in-plane field than previously known

Weighted Differentiation Composition Operator from Logarithmic Bloch Spaces to Zygmund-Type Spaces

Directory of Open Access Journals (Sweden)

Huiying Qu

2014-01-01

Full Text Available Let H( denote the space of all holomorphic functions on the unit disk of ℂ, u∈H( and let  n be a positive integer, φ a holomorphic self-map of , and μ a weight. In this paper, we investigate the boundedness and compactness of a weighted differentiation composition operator φ,unf(z=u(zf(n(φ(z,f∈H(, from the logarithmic Bloch spaces to the Zygmund-type spaces.

Self-consistent Maxwell-Bloch model of quantum-dot photonic-crystal-cavity lasers

Science.gov (United States)

Cartar, William; Mørk, Jesper; Hughes, Stephen

2017-08-01

We present a powerful computational approach to simulate the threshold behavior of photonic-crystal quantum-dot (QD) lasers. Using a finite-difference time-domain (FDTD) technique, Maxwell-Bloch equations representing a system of thousands of statistically independent and randomly positioned two-level emitters are solved numerically. Phenomenological pure dephasing and incoherent pumping is added to the optical Bloch equations to allow for a dynamical lasing regime, but the cavity-mediated radiative dynamics and gain coupling of each QD dipole (artificial atom) is contained self-consistently within the model. These Maxwell-Bloch equations are implemented by using Lumerical's flexible material plug-in tool, which allows a user to define additional equations of motion for the nonlinear polarization. We implement the gain ensemble within triangular-lattice photonic-crystal cavities of various length N (where N refers to the number of missing holes), and investigate the cavity mode characteristics and the threshold regime as a function of cavity length. We develop effective two-dimensional model simulations which are derived after studying the full three-dimensional passive material structures by matching the cavity quality factors and resonance properties. We also demonstrate how to obtain the correct point-dipole radiative decay rate from Fermi's golden rule, which is captured naturally by the FDTD method. Our numerical simulations predict that the pump threshold plateaus around cavity lengths greater than N =9 , which we identify as a consequence of the complex spatial dynamics and gain coupling from the inhomogeneous QD ensemble. This behavior is not expected from simple rate-equation analysis commonly adopted in the literature, but is in qualitative agreement with recent experiments. Single-mode to multimode lasing is also observed, depending on the spectral peak frequency of the QD ensemble. Using a statistical modal analysis of the average decay rates, we also

Zoonotic Trematode Metacercariae in Fish from Phnom Penh and Pursat, Cambodia

Science.gov (United States)

Chai, Jong-Yil; Na, Byoung-Kuk; Yong, Tai-Soon; Eom, Keeseon S.; Yoon, Cheong-Ha; Hoang, Eui-Hyug; Jeoung, Hoo-Gn; Socheat, Duong

2014-01-01

A survey was performed to investigate the infection status of freshwater fish with zoonotic trematode metacercariae in Phnom Penh and Pursat Province, Cambodia. All collected fish with ice were transferred to our laboratory and examined using the artificial digestion method. In fish from Phnom Penh, 2 kinds of metacercariae (Opisthorchis viverrini and Haplorchis yokogawai) were detected. O. viverrini metacercariae were positive in 37 (50.0%) of 74 fish in 11 species (average no. metacercariae/fish, 18.6). H. yokogawai metacercariae were detected in 23 (57.5%) of 40 fish in 5 species (average no. metacercariae/fish, 21.0). In fish from Pursat Province, 5 kinds of metacercariae (O. viverrini, H. yokogawai, Haplorchis pumilio, Centrocestus formosanus, and Procerovum sp.) were detected; O. viverrini metacercariae (n=3) in 2 fish species (Henicorhynchus lineatus and Puntioplites falcifer), H. yokogawai metacercariae (n=51) in 1 species (P. falcifer), H. pumilio metacercariae (n=476) in 2 species (H. lineatus and Pristolepis fasciata), C. formosanus metacercariae (n=1) in 1 species (H. lineatus), and Procerovum sp. metacercariae (n=63) in 1 species (Anabas testudineus). From the above results, it has been confirmed that various freshwater fish play the role of a second intermediate host for zoonotic trematodes (O. viverrini, H. yokogawai, H. pumilio, C. formosanus, and Procerovum sp.) in Cambodia. PMID:24623879

Dietary intake of heavy metals from eight highly consumed species of cultured fish and possible human health risk implications in Bangladesh

Directory of Open Access Journals (Sweden)

A.K.M. Atique Ullah

Full Text Available Concentrations of five heavy metals (Pb, Cd, Cr, As and Hg in eight highly consumed cultured fish species (Labeo rohita, Clarias gariepinus, Hypophthalmichthys molitrix, Cyprinus capio, Puntius sarana, Oreochromis mossambicus, Pangasius pangasius and Anabas testudineus collected from four wholesale markets of Dhaka city, Bangladesh (Karwan Bazar, Mohammadpur Town Hall, Newmarket and Mirpur-1 were measured using atomic absorption spectrometry (AAS in order to evaluate the potential human health risks from the consumption of fish. The estimated daily intake (EDI of all the studied heavy metals calculated on the basis of mean fish consumption of 49.5 g person−1 d−1 by Bangladeshi households indicated that no risk to people’s health with respect to the EDI of investigated heavy metals through the consumption of the fish samples. From the human health point of view, the estimation of non-carcinogenic risk indicated that intake of individual heavy metal through the consumption of fish was safe for human health, whereas, consumption of combined heavy metals suggested potential health risk to highly exposed consumers. However, the estimation of carcinogenic risk of arsenic due to the consumption of fish indicated that consumers remain at risk of cancer. Keywords: Heavy metals, Fish, Estimated daily intake, Carcinogenic and non-carcinogenic risk, Human health risks

Permittivity and Permeability for Floquet-Bloch Space Harmonics in Infinite 1D Magneto-Dielectric Periodic Structures

DEFF Research Database (Denmark)

Breinbjerg, Olav; Yaghjian, Arthur D.

2014-01-01

-Bloch space harmonics. We discuss how space harmonic permittivity and permeability can be expressed in seemingly different though equivalent forms, and we investigate these parameters of the zeroeth order space harmonic for a particular 1D periodic structure that is based on a previously reported 3D periodic...

The transmission factor of a bloch wall for spin waves whose wave vector is perpendicular to the wall (1961); Facteur de transmission d'une paroi de bloch pour des ondes de spin de vecteur d'onde normal a la paroi (1961)

Energy Technology Data Exchange (ETDEWEB)

Boutron, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

When, for a ferromagnetic, the anisotropic energy takes the form E= K sin{sup 2} {alpha}, the study of the propagation of spin waves of low energy across a Bloch wall leads to a one-dimensional Schrodinger equation in which is found a potential well which has the remarkable property of being completely transparent for all values of the incident wave energy. (author) [French] Dans un ferromagnetique, lorsque la densite d'energie d'anisotropie est de la forme E= K sin{sup 2} {alpha}, l'etude de la propagation des ondes de spin de faible energie a travers une paroi de Bloch, conduit a une equation de Schrodinger a une dimension, dans laquelle figure un puits de potentiel qui a la propriete remarquable d'etre completement transparent quelle que soit l'energie de l'onde incidente. (auteur)

Entanglement and the three-dimensionality of the Bloch ball

Energy Technology Data Exchange (ETDEWEB)

Masanes, Ll., E-mail: ll.masanes@gmail.com [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Müller, M. P. [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, D-69120 Heidelberg (Germany); Pérez-García, D. [Departamento de Analisis Matematico and IMI, Universidad Complutense de Madrid, 28040 Madrid (Spain); Augusiak, R. [ICFO-Institut de Ciencies Fotoniques, 08860 Castelldefels, Barcelona (Spain)

2014-12-15

We consider a very natural generalization of quantum theory by letting the dimension of the Bloch ball be not necessarily three. We analyze bipartite state spaces where each of the components has a d-dimensional Euclidean ball as state space. In addition to this, we impose two very natural assumptions: the continuity and reversibility of dynamics and the possibility of characterizing bipartite states by local measurements. We classify all these bipartite state spaces and prove that, except for the quantum two-qubit state space, none of them contains entangled states. Equivalently, in any of these non-quantum theories, interacting dynamics is impossible. This result reveals that “existence of entanglement” is the requirement with minimal logical content which singles out quantum theory from our family of theories.

Projectile-z3 and -z4 corrections to basic Bethe-Bloch stopping power theory and mean excitation energies of Al, Si, Ni, Ge, Se, Y, Ag and Au

International Nuclear Information System (INIS)

Porter, L.E.; Bryan, S.R.

1980-01-01

Three independent sets of measurements of the stopping power of solid elemental targets for alpha particles were previously analyzed in terms of basic Bethe-Bloch theory with the low velocity projectile-z 3 correction term included. These data for Al, Si, Ni, Ge, Se, Y, Ag and Au have now been analyzed with the Bloch projectile-z 4 term and a revised projectile-z 3 term incorporated in the Bethe-Bloch formula, the projectile-z 3 revision having been effected by variation of the single free parameter of the projectile-z 3 effect formalism. The value of this parameter, fixed at 1.8 in previous studies, which counteracts inclusion of the projectile-z 4 term is 1.3 +- 0.1 for all target elements except Si. (orig.)

A new distributional record of alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785) along Goa, central west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Sanaye, S.V.; Rivonker, C.U.; Ansari, Z.A; Sreepada, R.A

Present study is based on a single male specimen of alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785) collected from the bay-estuarine system of, Goa (central west coast of India) which is the new distributional record for this species. A...

Identification of Bloch-modes in hollow-core Photonic Crystal Fiber cladding

DEFF Research Database (Denmark)

Couny, F.; Benabid, F.; Roberts, John

2007-01-01

We report on the experimental visualization of the cladding Bloch-modes of a hollow-core photonic crystal fiber. Both spectral and spatial field information is extracted using the approach, which is based on measurement of the near-field and Fresnel-zone that results after propagation over a short...... length of fiber. A detailed study of the modes near the edges of the band gap shows that it is formed by the influence of three types of resonator: the glass interstitial apex, the silica strut which joins the neighboring apexes, and the air hole. The cladding electromagnetic field which survives...

Notes on the genus Amphiprion Bloch & Schneider, 1801 (Teleostei: Pomacentridae) and its host sea anemones in the Seychelles

NARCIS (Netherlands)

Hartog, den J.C.

1997-01-01

The genus Amphiprion Bloch & Schneider, 1801, is represented in the Seychelles by two species, A. akallopisos Bleeker, 1853, and the endemic A. fuscocaudatus Allen, 1972. Throughout its distributional range Amphiprion akallopisos has exclusively been recorded to associate with the clownfish anemones

A Bloch-Torrey Equation for Diffusion in a Deforming Media

Energy Technology Data Exchange (ETDEWEB)

Rohmer, Damien; Gullberg, Grant T.

2006-12-29

Diffusion Tensor Magnetic Resonance Imaging (DTMRI)technique enables the measurement of diffusion parameters and therefore,informs on the structure of the biological tissue. This technique isapplied with success to the static organs such as brain. However, thediffusion measurement on the dynamically deformable organs such as thein-vivo heart is a complex problem that has however a great potential inthe measurement of cardiac health. In order to understand the behavior ofthe Magnetic Resonance (MR)signal in a deforming media, the Bloch-Torreyequation that leads the MR behavior is expressed in general curvilinearcoordinates. These coordinates enable to follow the heart geometry anddeformations through time. The equation is finally discretized andpresented in a numerical formulation using implicit methods, in order toget a stable scheme that can be applied to any smooth deformations.Diffusion process enables the link between the macroscopic behavior ofmolecules and themicroscopic structure in which they evolve. Themeasurement of diffusion in biological tissues is therefore of majorimportance in understanding the complex underlying structure that cannotbe studied directly. The Diffusion Tensor Magnetic ResonanceImaging(DTMRI) technique enables the measurement of diffusion parametersand therefore provides information on the structure of the biologicaltissue. This technique has been applied with success to static organssuch as the brain. However, diffusion measurement of dynamicallydeformable organs such as the in-vivo heart remains a complex problem,which holds great potential in determining cardiac health. In order tounderstand the behavior of the magnetic resonance (MR) signal in adeforming media, the Bloch-Torrey equation that defines the MR behavioris expressed in general curvilinear coordinates. These coordinates enableus to follow the heart geometry and deformations through time. Theequation is finally discretized and presented in a numerical formulationusing

Full-angle Negative Reflection with An Ultrathin Acoustic Gradient Metasurface: Floquet-Bloch Modes Perspective and Experimental Verification

KAUST Repository

Liu, Bingyi

2017-07-01

Metasurface with gradient phase response offers new alternative for steering the propagation of waves. Conventional Snell\\'s law has been revised by taking the contribution of local phase gradient into account. However, the requirement of momentum matching along the metasurface sets its nontrivial beam manipulation functionality within a limited-angle incidence. In this work, we theoretically and experimentally demonstrate that the acoustic gradient metasurface supports the negative reflection for full-angle incidence. The mode expansion theory is developed to help understand how the gradient metasurface tailors the incident beams, and the full-angle negative reflection occurs when the first negative order Floquet-Bloch mode dominates. The coiling-up space structures are utilized to build desired acoustic gradient metasurface and the full-angle negative reflections have been perfectly verified by experimental measurements. Our work offers the Floquet-Bloch modes perspective for qualitatively understanding the reflection behaviors of the acoustic gradient metasurface and enables a new degree of the acoustic wave manipulating.

Fast-forward scaling theory for phase imprinting on a BEC: creation of a wave packet with uniform momentum density and loading to Bloch states without disturbance

Science.gov (United States)

Masuda, Shumpei; Nakamura, Katsuhiro; Nakahara, Mikio

2018-02-01

We study phase imprinting on Bose-Einstein condensates (BECs) with the fast-forward scaling theory revealing a nontrivial scaling property in quantum dynamics. We introduce a wave packet with uniform momentum density (WPUM) which has peculiar properties but is short-lived. The fast-forward scaling theory is applied to derive the driving potential for creation of the WPUMs in a predetermined time. Fast manipulation is essential for the creation of WPUMs because of the instability of the state. We also study loading of a BEC into a predetermined Bloch state in the lowest band from the ground state of a periodic potential. Controlled linear potential is not sufficient for creation of the Bloch state with large wavenumber because the change in the amplitude of the order parameter is not negligible. We derive the exact driving potential for creation of predetermined Bloch states using the obtained theory.

Bloch-Nordsieck estimates of high-temperature QED

International Nuclear Information System (INIS)

Fried, H. M.; Sheu, Y.-M.; Grandou, T.

2008-01-01

In anticipation of a subsequent application to QCD, we consider the case of QED at high temperature. We introduce a Fradkin representation into the exact, Schwingerian, functional expression of a fermion propagator, as well as a new and relevant version of the Bloch-Nordsieck model, which extracts the soft contributions of every perturbative graph, in contradistinction to the assumed separation of energy scales of previous semiperturbative treatments. Our results are applicable to the absorption of a fast particle which enters a heat bath, as well as to the propagation of a symmetric pulse within the thermal medium due to the appearance of an instantaneous, shockwave-like source acting in the medium. An exponentially decreasing time dependence of the incident particle's initial momentum combines with a stronger decrease in the particle's energy, estimated by a sum over all Matsubara frequencies, to model an initial 'fireball', which subsequently decays in a Gaussian fashion. When extended to QCD, qualitative applications could be made to RHIC scattering, in which a fireball appears, expands, and is damped away

Puff and bite: the relationship between the glucocorticoid stress response and anti-predator performance in checkered puffer (Sphoeroides testudineus).

Science.gov (United States)

Cull, Felicia; O'Connor, Constance M; Suski, Cory D; Shultz, Aaron D; Danylchuk, Andy J; Cooke, Steven J

2015-04-01

Individual variation in the endocrine stress response has been linked to survival and performance in a variety of species. Here, we evaluate the relationship between the endocrine stress response and anti-predator behaviors in wild checkered puffers (Sphoeroides testudineus) captured at Eleuthera Island, Bahamas. The checkered puffer has a unique and easily measurable predator avoidance strategy, which is to inflate or 'puff' to deter potential predators. In this study, we measured baseline and stress-induced circulating glucocorticoid levels, as well as bite force, a performance measure that is relevant to both feeding and predator defence, and 'puff' performance. We found that puff performance and bite force were consistent within individuals, but generally decreased following a standardized stressor. Larger puffers were able to generate a higher bite force, and larger puffers were able to maintain a more robust puff performance following a standardized stressor relative to smaller puffers. In terms of the relationship between the glucocorticoid stress response and performance metrics, we found no relationship between post-stress glucocorticoid levels and either puff performance or bite force. However, we did find that baseline glucocorticoid levels predicted the ability of a puffer to maintain a robust puff response following a repeated stressor, and this relationship was more pronounced in larger individuals. Our work provides a novel example of how baseline glucocorticoids can predict a fitness-related anti-predator behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

Manipulation of Bloch surface waves: from subwavelength focusing to nondiffracting beam

Science.gov (United States)

Kim, Myun-Sik; Herzig, Hans Peter

2018-01-01

We present a different type of electromagnetic surface wave than a surface plasmon polariton (SPP), called Bloch surface wave (BSW). BSWs are sustained by dielectric multilayers, and therefore they do not suffer from dissipation. Their propagation length is unbeatably long, e.g., over several millimeters. Thanks to this feature, larger integrations of 2D photonic chips are realizable. To do this, 2D optical components and corresponding techniques are necessary to manipulate in-plane propagation of surface waves. We overview recent progresses of the BSW research on manipulation techniques and developed components. Our study will provide a good guideline of the BSW components for users.

Third harmonic generation by Bloch-oscillating electrons in a quasioptical array

International Nuclear Information System (INIS)

Ghosh, A.W.; Wanke, M.C.; Allen, S.J.; Wilkins, J.W.

1999-01-01

We compute the third harmonic field generated by Bloch-oscillating electrons in a quasioptical array of superlattices under THz irradiation. The third harmonic power transmitted oscillates with the internal electric field, with nodes associated with Bessel functions in eEd/ℎω. The nonlinear response of the array causes the output power to be a multivalued function of the incident laser power. The output can be optimized by adjusting the frequency of the incident pulse to match one of the Fabry-Pacute erot resonances in the substrate. Within the transmission-line model of the array, the maximum conversion efficiency is 0.1%. copyright 1999 American Institute of Physics

Philippe Bloch: Reducing distance between experiments and CERN

CERN Multimedia

2009-01-01

With its unique combination of several hundred staff members and thousands of users from around the world sharing offices and physics data and profiting from mutually beneficial exchanges of know-how and expertise, the PH Department is a good example of a successful worldwide collaboration, set up as it was to construct and run the Laboratory’s physics experiments. The PH Depart-ment has always played host to thousands of users that contribute to CERN experiments and work on them, and whose numbers are set to grow in the years to come. With his long-standing experience as a user and then as the head of the CERN group within the CMS collaboration, Philippe Bloch, the new PH Department Head, is in favour of closer links between the Department and the experiments. "I think that the PH management should have a direct link to the experiments, and to do so we are holding regular management team meetings comprising members of the Department’s management and the e...

Boundedness and compactness of a new product-type operator from a general space to Bloch-type spaces

Directory of Open Access Journals (Sweden)

Stevo Stević

2016-09-01

Full Text Available Abstract We characterize the boundedness and compactness of a product-type operator, which, among others, includes all the products of the single composition, multiplication, and differentiation operators, from a general space to Bloch-type spaces. We also give some upper and lower bounds for the norm of the operator.

Motives and algebraic cycles a celebration in honour of Spencer J. Bloch

CERN Document Server

Jeu, Rob de; Lewis, James D

2009-01-01

Spencer J. Bloch has, and continues to have, a profound influence on the subject of Algebraic K-Theory, Cycles and Motives. This book, which is comprised of a number of independent research articles written by leading experts in the field, is dedicated in his honour, and gives a snapshot of the current and evolving nature of the subject. Some of the articles are written in an expository style, providing a perspective on the current state of the subject to those wishing to learn more about it. Others are more technical, representing new developments and making them especially interesting to res

Self-consistent Maxwell-Bloch model of quantum-dot photonic-crystal-cavity lasers

DEFF Research Database (Denmark)

Cartar, William; Mørk, Jesper; Hughes, Stephen

2017-01-01

-level emitters are solved numerically. Phenomenological pure dephasing and incoherent pumping is added to the optical Bloch equations to allow for a dynamical lasing regime, but the cavity-mediated radiative dynamics and gain coupling of each QD dipole (artificial atom) is contained self-consistently within......-mode to multimode lasing is also observed, depending on the spectral peak frequency of the QD ensemble. Using a statistical modal analysis of the average decay rates, we also show how the average radiative decay rate decreases as a function of cavity size. In addition, we investigate the role of structural disorder...

High-order-harmonic generation from solids: The contributions of the Bloch wave packets moving at the group and phase velocities

Science.gov (United States)

Du, Tao-Yuan; Huang, Xiao-Huan; Bian, Xue-Bin

2018-01-01

We study numerically the Bloch electron wave-packet dynamics in periodic potentials to simulate laser-solid interactions. We introduce an alternative perspective in the coordinate space combined with the motion of the Bloch electron wave packets moving at group and phase velocities under the laser fields. This model interprets the origins of the two contributions (intra- and interband transitions) in the high-order harmonic generation (HHG) processes by investigating the local and global behaviours of the wave packets. It also elucidates the underlying physical picture of the HHG intensity enhancement by means of carrier-envelope phase, chirp, and inhomogeneous fields. It provides a deep insight into the emission of high-order harmonics from solids. This model is instructive for experimental measurements and provides an alternative avenue to distinguish mechanisms of the HHG from solids in different laser fields.

Design of Slow and Fast Light Photonic Crystal Waveguides for Single-photon Emission Using a Bloch Mode Expansion Technique

DEFF Research Database (Denmark)

de Lasson, Jakob Rosenkrantz; Rigal, B.; Kapon, E.

We design slow and fast light photonic crystal waveguides for single-photon emission using a Bloch mode expansion and scattering matrix technique. We propose slow light designs that increase the group index-waveguide mode volume ratio for larger Purcell enhancement, and address efficient slow-to-...

Effects of gamma radiations on certain tissues of heteropneustes fossils bloch

International Nuclear Information System (INIS)

Purohit, R.K.; Rathore, N.; Ahluwalia, P.; Srivastava, M.; Gupta, M.L.

1992-01-01

In the present investigation effect of gamma radiation on certain tissues (kidney, stomach and gills) of Heteropneustes fossilis Bloch, an Indian Cat fish, were studied. The fish were irradiated with 10 Gy of gamma radiations at the dose rate of 1.60 Gy/minute from a 60 Co source. Five fish were autopsied at each post-irradiation time of 1,2,3,7,15 and 30 days. Radiation induced histopathology was observed in all the tissues studied. The radio lesions appeared on day-1 after exposure which became exaggerated on day-2 and 3. Signs of recovery were noticed on day-7 which progressed on day-15 and normal histology was observed on day-30. (author). 18 refs

A Bloch-Torrey Equation for Diffusion in a Deforming Media

International Nuclear Information System (INIS)

Rohmer, Damien; Gullberg, Grant T.

2006-01-01

Diffusion Tensor Magnetic Resonance Imaging (DTMRI)technique enables the measurement of diffusion parameters and therefore, informs on the structure of the biological tissue. This technique is applied with success to the static organs such as brain. However, the diffusion measurement on the dynamically deformable organs such as the in-vivo heart is a complex problem that has however a great potential in the measurement of cardiac health. In order to understand the behavior of the Magnetic Resonance (MR)signal in a deforming media, the Bloch-Torrey equation that leads the MR behavior is expressed in general curvilinear coordinates. These coordinates enable to follow the heart geometry and deformations through time. The equation is finally discredited and presented in a numerical formulation using implicit methods, in order to get a stable scheme that can be applied to any smooth deformations. Diffusion process enables the link between the macroscopic behavior of molecules and the microscopic structure in which they evolve. The measurement of diffusion in biological tissues is therefore of major importance in understanding the complex underlying structure that cannot be studied directly. The Diffusion Tensor Magnetic Resonance Imaging(DTMRI) technique enables the measurement of diffusion parameters and therefore provides information on the structure of the biological tissue. This technique has been applied with success to static organs such as the brain. However, diffusion measurement of dynamically deformable organs such as the in-vivo heart remains a complex problem, which holds great potential in determining cardiac health. In order to understand the behavior of the magnetic resonance (MR) signal in a deforming media, the Bloch-Torrey equation that defines the MR behavior is expressed in general curvilinear coordinates. These coordinates enable us to follow the heart geometry and deformations through time. The equation is finally discredited and presented in a

Bloch Modes and Evanescent Modes of Photonic Crystals: Weak Form Solutions Based on Accurate Interface Triangulation

Directory of Open Access Journals (Sweden)

Matthias Saba

2015-01-01

Full Text Available We propose a new approach to calculate the complex photonic band structure, both purely dispersive and evanescent Bloch modes of a finite range, of arbitrary three-dimensional photonic crystals. Our method, based on a well-established plane wave expansion and the weak form solution of Maxwell’s equations, computes the Fourier components of periodic structures composed of distinct homogeneous material domains from a triangulated mesh representation of the inter-material interfaces; this allows substantially more accurate representations of the geometry of complex photonic crystals than the conventional representation by a cubic voxel grid. Our method works for general two-phase composite materials, consisting of bi-anisotropic materials with tensor-valued dielectric and magnetic permittivities ε and μ and coupling matrices ς. We demonstrate for the Bragg mirror and a simple cubic crystal closely related to the Kelvin foam that relatively small numbers of Fourier components are sufficient to yield good convergence of the eigenvalues, making this method viable, despite its computational complexity. As an application, we use the single gyroid crystal to demonstrate that the consideration of both conventional and evanescent Bloch modes is necessary to predict the key features of the reflectance spectrum by analysis of the band structure, in particular for light incident along the cubic [111] direction.

Matter-wave solitons and finite-amplitude Bloch waves in optical lattices with a spatially modulated nonlinearity

OpenAIRE

Zhang, Jie-Fang; Li, Yi-Shen; Meng, Jianping; Wu, Lei; Malomed, Boris A.

2010-01-01

We investigate solitons and nonlinear Bloch waves in Bose-Einstein condensates trapped in optical lattices. By introducing specially designed localized profiles of the spatial modulation of the attractive nonlinearity, we construct an infinite number of exact soliton solutions in terms of the Mathieu and elliptic functions, with the chemical potential belonging to the semi-infinite bandgap of the optical-lattice-induced spectrum. Starting from the exact solutions, we employ the relaxation met...

Plasmonic Photonic-Crystal Slabs: Visualization of the Bloch Surface Wave Resonance for an Ultrasensitive, Robust and Reusable Optical Biosensor

Directory of Open Access Journals (Sweden)

Alexander V. Baryshev

2014-12-01

Full Text Available A one-dimensional photonic crystal (PhC with termination by a metal film—a plasmonic photonic-crystal slab—has been theoretically analyzed for its optical response at a variation of the dielectric permittivity of an analyte and at a condition simulating the molecular binding event. Visualization of the Bloch surface wave resonance (SWR was done with the aid of plasmon absorption in a dielectric/metal/dielectric sandwich terminating a PhC. An SWR peak in spectra of such a plasmonic photonic crystal (PPhC slab comprising a noble or base metal layer was shown to be sensitive to a negligible variation of refractive index of a medium adjoining to the slab. As a consequence, the considered PPhC-based optical sensors exhibited an enhanced sensitivity and a good robustness in comparison with the conventional surface-plasmon and Bloch surface wave sensors. The PPhC biosensors can be of practical importance because the metal layer is protected by a capping dielectric layer from contact with analytes and, consequently, from deterioration.

Computational Diffusion Magnetic Resonance Imaging Based on Time-Dependent Bloch NMR Flow Equation and Bessel Functions.

Science.gov (United States)

Awojoyogbe, Bamidele O; Dada, Michael O; Onwu, Samuel O; Ige, Taofeeq A; Akinwande, Ninuola I

2016-04-01

Magnetic resonance imaging (MRI) uses a powerful magnetic field along with radio waves and a computer to produce highly detailed "slice-by-slice" pictures of virtually all internal structures of matter. The results enable physicians to examine parts of the body in minute detail and identify diseases in ways that are not possible with other techniques. For example, MRI is one of the few imaging tools that can see through bones, making it an excellent tool for examining the brain and other soft tissues. Pulsed-field gradient experiments provide a straightforward means of obtaining information on the translational motion of nuclear spins. However, the interpretation of the data is complicated by the effects of restricting geometries as in the case of most cancerous tissues and the mathematical concept required to account for this becomes very difficult. Most diffusion magnetic resonance techniques are based on the Stejskal-Tanner formulation usually derived from the Bloch-Torrey partial differential equation by including additional terms to accommodate the diffusion effect. Despite the early success of this technique, it has been shown that it has important limitations, the most of which occurs when there is orientation heterogeneity of the fibers in the voxel of interest (VOI). Overcoming this difficulty requires the specification of diffusion coefficients as function of spatial coordinate(s) and such a phenomenon is an indication of non-uniform compartmental conditions which can be analyzed accurately by solving the time-dependent Bloch NMR flow equation analytically. In this study, a mathematical formulation of magnetic resonance flow sequence in restricted geometry is developed based on a general second order partial differential equation derived directly from the fundamental Bloch NMR flow equations. The NMR signal is obtained completely in terms of NMR experimental parameters. The process is described based on Bessel functions and properties that can make it

Near-field imaging of light propagation in photonic crystal waveguides: Explicit role of Bloch harmonics

DEFF Research Database (Denmark)

Bozhevolnyi, Sergey I.; Volkov, V.S.; Søndergaard, Thomas

2002-01-01

We employ a collection scanning near-field optical microscope (SNOM) to image the propagation of light at telecommunication wavelengths along straight and bent regions of silicon-on-insulator photonic crystal waveguides (PCWs) formed by removing a single row of holes in the triangular 410-nm...... the interference between a quasihomogeneous background field and Bloch harmonics of the PCW mode, we account for spatial frequency spectra of the intensity variations and determine the propagation constant of the PCW mode at 1520 nm. The possibilities and limitations of SNOM imaging for the characterization...

Exact solutions for fermionic Green's functions in the Bloch-Nordsieck approximation of QED

International Nuclear Information System (INIS)

Kernemann, A.; Stefanis, N.G.

1989-01-01

A set of new closed-form solutions for fermionic Green's functions in the Bloch-Nordsieck approximation of QED is presented. A manifestly covariant phase-space path-integral method is applied for calculating the n-fermion Green's function in a classical external field. In the case of one and two fermions, explicit expressions for the full Green's functions are analytically obtained, with renormalization carried out in the modified minimal subtraction scheme. The renormalization constants and the corresponding anomalous dimensions are determined. The mass-shell behavior of the two-fermion Green's function is investigated in detail. No assumptions are made concerning the structure of asymptotic states and no IR cutoff is used in the calculations

Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains

International Nuclear Information System (INIS)

Sun, H.Y.; Hu, H.N.; Sun, Y.P.; Nie, X.F.

2004-01-01

Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains (IIDs) was investigated, and a critical in-plane field range [H ip 1 ,H ip 2 ] of which vertical-Bloch lines (VBLs) annihilated in IIDs is found under rotating in-plane field (H ip 1 is the maximal critical in-plane-field of which hard domains remain stable, H ip 2 is the minimal critical in-plane-field of which all of the hard domains convert to soft bubbles (SBs, without VBLs)). It shows that the in-plane field range [H ip 1 , H ip 2 ] changes with the change of the rotating angle Δφ H ip 1 maintains stable, while H ip 2 decreases with the decreasing of rotating angle Δφ. Comparing it with the spontaneous shrinking experiment of IIDs under both bias field and in-plane field, we presume that under the application of in-plane field there exists a direction along which the VBLs in the domain walls annihilate most easily, and it is in the direction that domain walls are perpendicular to the in-plane field

Perturbation theory for the bloch electrons on strongly coupled chains in both uniform electric and magnetic fields

International Nuclear Information System (INIS)

Zhao, X.G.; Chen, S.G.

1992-01-01

In this paper, the energy spectrum and the wave functions for a tight-binding Bloch electron on coupled chains under the action of both uniform electric and magnetic fields are studied in detail. Exact results are obtained for the case when the coupling between chains is large by using the perturbation theory, from which it is found that the spectrum is that of two interspaced Stark ladders. The magnetic field dependence of the energy spectrum is also discussed

Influence of in-plane field on vertical Bloch line in the walls of the second kind of dumbbell domains at various temperatures

International Nuclear Information System (INIS)

Xu, J.P.; Liu, S.P.; Guo, G.X.; Zhen, C.M.; Tang, G.D.; Sun, H.Y.; Nie, X.F.

2004-01-01

The stability of vertical Bloch lines (VBLs) in the second kind of dumbbell domain (IIDs) walls in liquid phase epitaxy garnet bubble films subjected to an in-plane field at various temperatures is studied experimentally. It is found that there exists a critical in-plane field range depending on temperature, in which vertical Bloch lines (VBLs) in the second kind of IIDs walls are unstable, i.e., [Hip(1)(T),Hip(2)(T)]. Here, Hip(1)(T) is the initial critical in-plane field at which VBLs in the walls of IIDs annihilate; while Hip(2)(T) is the lowest in-plane field at which all VBLs in the walls of IIDs have annihilated completely. Also, the critical in-plane field range [Hip(1)(T),Hip(2)(T)],Hip(1)(T) and Hip(2)(T) all decrease with the temperature increasing. Hip(1)(T) and Hip(2)(T) reach zero at T0' and T0, respectively

Nonlinear tunneling of bright and dark rogue waves in combined nonlinear Schrödinger and Maxwell-Bloch systems

Science.gov (United States)

Raju, Thokala Soloman; Pal, Ritu

2018-05-01

We derive the analytical rogue wave solutions for the generalized inhomogeneous nonlinear Schrödinger-Maxwell-Bloch (GINLS-MB) equation describing the pulse propagation in erbium-doped fibre system. Then by suitably choosing the inhomogeneous parameters, we delineate the tunneling properties of rogue waves through dispersion and nonlinearity barriers or wells. Finally, we demonstrate the propagating characteristics of optical solitons by considering their tunneling through periodic barriers by the proper choice of external potential.

Bloch oscillations of quasispin polaritons in a magneto-optically controlled atomic ensemble

International Nuclear Information System (INIS)

Jiang, Chang; Lu, Jing; Zhou, Lan

2012-01-01

We consider the propagation of quantized polarized light in a magneto-optically-manipulated atomic ensemble with a tripod configuration. A polariton formalism is applied when the medium is subjected to a washboard magnetic field under electromagnetically-induced transparency. The dark-state polariton with multiple components is achieved. We analyze the quantum dynamics of the dark-state polariton using experimental data from the rubidium D1-line. It is found that one component propagates freely, however the wave packet trajectory of the other component performs Bloch oscillations. -- Highlights: ► We study the wave–particle dualism of quasiparticles in a magneto-optical medium. ► We generate a “spin”-component dark-state polariton. ► Magnetic fields lead to oscillation and free propagation of a dark-state polariton. ► Our approach shows the role of entanglement of degrees of freedom of photons.

Bloch oscillations of quasispin polaritons in a magneto-optically controlled atomic ensemble

Energy Technology Data Exchange (ETDEWEB)

Jiang, Chang [Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Department of Physics, Hunan Normal University, Changsha 410081 (China); Lu, Jing, E-mail: lujing@hunnu.edu.cn [Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Department of Physics, Hunan Normal University, Changsha 410081 (China); Zhou, Lan [Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Department of Physics, Hunan Normal University, Changsha 410081 (China)

2012-10-01

We consider the propagation of quantized polarized light in a magneto-optically-manipulated atomic ensemble with a tripod configuration. A polariton formalism is applied when the medium is subjected to a washboard magnetic field under electromagnetically-induced transparency. The dark-state polariton with multiple components is achieved. We analyze the quantum dynamics of the dark-state polariton using experimental data from the rubidium D1-line. It is found that one component propagates freely, however the wave packet trajectory of the other component performs Bloch oscillations. -- Highlights: ► We study the wave–particle dualism of quasiparticles in a magneto-optical medium. ► We generate a “spin”-component dark-state polariton. ► Magnetic fields lead to oscillation and free propagation of a dark-state polariton. ► Our approach shows the role of entanglement of degrees of freedom of photons.

Bloch surface waves confined in one dimension with a single polymeric nanofibre

Science.gov (United States)

Wang, Ruxue; Xia, Hongyan; Zhang, Douguo; Chen, Junxue; Zhu, Liangfu; Wang, Yong; Yang, Erchan; Zang, Tianyang; Wen, Xiaolei; Zou, Gang; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Lakowicz, Joseph R.

2017-02-01

Polymeric fibres with small radii (such as ≤125 nm) are delicate to handle and should be laid down on a solid substrate to obtain practical devices. However, placing these nanofibres on commonly used glass substrates prevents them from guiding light. In this study, we numerically and experimentally demonstrate that when the nanofibre is placed on a suitable dielectric multilayer, it supports a guided mode, a Bloch surface wave (BSW) confined in one dimension. The physical origin of this new mode is discussed in comparison with the typical two-dimensional BSW mode. Polymeric nanofibres are easily fabricated to contain fluorophores, which make the dielectric nanofibre and multilayer configuration suitable for developing a large range of new nanometric scale devices, such as processor-memory interconnections, devices with sensitivity to target analytes, incident polarization and multi-colour BSW modes.

Bloch surface wave structures for high sensitivity detection and compact waveguiding

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Khan, Muhammad Umar; Corbett, Brian

2016-01-01

Resonant propagating waves created on the surface of a dielectric multilayer stack, called Bloch surface waves (BSW), can be designed for high sensitivity monitoring of the adjacent refractive index as an alternative platform to the metal-based surface plasmon resonance (SPR) sensing. The resonant wavelength and polarization can be designed by engineering of the dielectric layers unlike the fixed resonance of SPR, while the wide bandwidth low loss of dielectrics permits sharper resonances, longer propagation lengths and thus their use in waveguiding devices. The transparency of the dielectrics allows the excitation and monitoring of surface-bound fluorescent molecules. We review the recent developments in this technology. We show the advantages that can be obtained by using high index contrast layered structures. Operating at 1550 nm wavelengths will allow the BSW sensors to be implemented in the silicon photonics platform where active waveguiding can be used in the realization of compact planar integrated circuits for multi-parameter sensing.

THE ACTION OF CORAGEN INSECTICIDE ON CERTAIN PHYSIOLOGICAL BIOMARKERS ON CARASSIUS AURATUS GIBELIO BLOCH L. 1758

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Claudiu Alexandru Baciu

2015-12-01

Full Text Available In our researches we have determined the variation of certain physiological indexes, such as the oxygen consume, the breathing rhythm, the glycaemia and the number of red blood cells under the action of Coragen insecticide on Carassius auratus gibelio Bloch. Under the action of Coragen, we have registered significant changes in the oxygen consume, the breathing rhythm, the number of red blood cells and glycemia at the Carassius auratus gibelio Bloch items, considered as answers to the stress provoked by emissions. The highest variations of the physiological indexes, from the perspective of the percentage, were noticed at the glycemia, which at the mark was 28 mg/dl, and in the treated sample, with 0.1 ml/l Coragen is 42 mg/dl, representing a 50% growth and at the breathing rhythm in 24 hours, where values significantly decreased with 41.18% at the concentration of 0.07 ml/l and with 39.33% at the concentrations of 0.05 and 0.1 ml/l Coragen. The slightest variations of the physiological indexes, from the perspective of percentage, were noticed at the oxygen consumption, which, at the mark is of 55.302 ml oxygen/kg/hour, and for the treated sample, with 0.1 ml/l Coragen is 34.81 ml oxygen/kg/hour, representing a decrease of 37.06% in 24 hours and the number of red blood cells, where the values have significantly decrease with 9.58%, 13.48%, respectively 18.44% for the concentrations of 0.05, 0.07 and 0.1 ml/l Coragen.

Bloch oscillations of ultracold atoms and measurement of the fine structure constant; Oscillations de Bloch d'atomes ultrafroids et mesure de la constante de structure fine

Energy Technology Data Exchange (ETDEWEB)

Clade, P

2005-10-15

From a measurement of the recoil velocity of an atom absorbing a photon, it is possible to deduce a determination of the ratio h/m between the Planck constant and the mass of the atoms and then to deduce a value of the fine structure constant alpha. To do this measurement, we use the technique of Bloch oscillations, which allows us to transfer a large number of recoils to atoms. A velocity sensor, based on velocity selective Raman transition, enables us to measure the momentum transferred to the atoms. A measurement with a statistical uncertainty of 4.4 10{sup -9}, in conjunction with a careful study of systematic effects (5 10{sup -9}), has led us to a determination of alpha with an uncertainty of 6.7 10{sup -9}: {alpha}{sup -1}(Rb) = 137.03599878 (91). This uncertainty is similar to the uncertainty of the best determinations of alpha based on atom interferometry. (author)

Illuminating "spin-polarized" Bloch wave-function projection from degenerate bands in decomposable centrosymmetric lattices

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Li, Pengke; Appelbaum, Ian

2018-03-01

The combination of space inversion and time-reversal symmetries results in doubly degenerate Bloch states with opposite spin. Many lattices with these symmetries can be constructed by combining a noncentrosymmetric potential (lacking this degeneracy) with its inverted copy. Using simple models, we unravel the evolution of local spin splitting during this process of inversion symmetry restoration, in the presence of spin-orbit interaction and sublattice coupling. Importantly, through an analysis of quantum mechanical commutativity, we examine the difficulty of identifying states that are simultaneously spatially segregated and spin polarized. We also explain how surface-sensitive experimental probes (such as angle-resolved photoemission spectroscopy, or ARPES) of "hidden spin polarization" in layered materials are susceptible to unrelated spin splitting intrinsically induced by broken inversion symmetry at the surface.

Asymmetric rogue waves, breather-to-soliton conversion, and nonlinear wave interactions in the Hirota–Maxwell–Bloch system

International Nuclear Information System (INIS)

Wang Lei; Zhu Yujie; Wang Ziqi; Xu Tao; Qi Fenghua; Xue Yushan

2016-01-01

We study the nonlinear localized waves on constant backgrounds of the Hirota–Maxwell–Bloch (HMB) system arising from the erbium doped fibers. We derive the asymmetric breather, rogue wave (RW) and semirational solutions of the HMB system. We show that the breather and RW solutions can be converted into various soliton solutions. Under different conditions of parameters, we calculate the locus of the eigenvalues on the complex plane which converts the breathers or RWs into solitons. Based on the second-order solutions, we investigate the interactions among different types of nonlinear waves including the breathers, RWs and solitons. (author)

Asymmetric Rogue Waves, Breather-to-Soliton Conversion, and Nonlinear Wave Interactions in the Hirota-Maxwell-Bloch System

Science.gov (United States)

Wang, Lei; Zhu, Yu-Jie; Wang, Zi-Qi; Xu, Tao; Qi, Feng-Hua; Xue, Yu-Shan

2016-02-01

We study the nonlinear localized waves on constant backgrounds of the Hirota-Maxwell-Bloch (HMB) system arising from the erbium doped fibers. We derive the asymmetric breather, rogue wave (RW) and semirational solutions of the HMB system. We show that the breather and RW solutions can be converted into various soliton solutions. Under different conditions of parameters, we calculate the locus of the eigenvalues on the complex plane which converts the breathers or RWs into solitons. Based on the second-order solutions, we investigate the interactions among different types of nonlinear waves including the breathers, RWs and solitons.

Emergence of quasiparticle Bloch states in artificial crystals crafted atom-by-atom

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Jan Girovsky, Jose L. Lado, Floris E. Kalff, Eleonora Fahrenfort, Lucas J. J. M. Peters, Joaquín Fernández-Rossier, Alexander F. Otte

2017-06-01

Full Text Available The interaction of electrons with a periodic potential of atoms in crystalline solids gives rise to band structure. The band structure of existing materials can be measured by photoemission spectroscopy and accurately understood in terms of the tight-binding model, however not many experimental approaches exist that allow to tailor artificial crystal lattices using a bottom-up approach. The ability to engineer and study atomically crafted designer materials by scanning tunnelling microscopy and spectroscopy (STM/STS helps to understand the emergence of material properties. Here, we use atom manipulation of individual vacancies in a chlorine monolayer on Cu(100 to construct one- and two-dimensional structures of various densities and sizes. Local STS measurements reveal the emergence of quasiparticle bands, evidenced by standing Bloch waves, with tuneable dispersion. The experimental data are understood in terms of a tight-binding model combined with an additional broadening term that allows an estimation of the coupling to the underlying substrate.

Bloch oscillations of ultracold atoms and measurement of the fine structure constant

International Nuclear Information System (INIS)

Clade, P.

2005-10-01

From a measurement of the recoil velocity of an atom absorbing a photon, it is possible to deduce a determination of the ratio h/m between the Planck constant and the mass of the atoms and then to deduce a value of the fine structure constant alpha. To do this measurement, we use the technique of Bloch oscillations, which allows us to transfer a large number of recoils to atoms. A velocity sensor, based on velocity selective Raman transition, enables us to measure the momentum transferred to the atoms. A measurement with a statistical uncertainty of 4.4 10 -9 , in conjunction with a careful study of systematic effects (5 10 -9 ), has led us to a determination of alpha with an uncertainty of 6.7 10 -9 : α -1 (Rb) = 137.03599878 (91). This uncertainty is similar to the uncertainty of the best determinations of alpha based on atom interferometry. (author)

Corrections to Newton’s law of gravitation - application to hybrid Bloch brane

Science.gov (United States)

Almeida, C. A. S.; Veras, D. F. S.; Dantas, D. M.

2018-02-01

We present in this work, the calculations of corrections in the Newton’s law of gravitation due to Kaluza-Klein gravitons in five-dimensional warped thick braneworld scenarios. We consider here a recently proposed model, namely, the hybrid Bloch brane. This model couples two scalar fields to gravity and is engendered from a domain wall-like defect. Also, two other models the so-called asymmetric hybrid brane and compact brane are considered. Such models are deformations of the ϕ 4 and sine-Gordon topological defects, respectively. Therefore we consider the branes engendered by such defects and we also compute the corrections in their cases. In order to attain the mass spectrum and its corresponding eigenfunctions which are the essential quantities for computing the correction to the Newtonian potential, we develop a suitable numerical technique. The calculation of slight deviations in the gravitational potential may be used as a selection tool for braneworld scenarios matching with future experimental measurements in high energy collisions

A study on Polonium-210 distribution in the Koraiyar river ecosystem, Tiruchirappalli - India

International Nuclear Information System (INIS)

Krishnamoorthy, R.; Syed Mohamed, H.E.; Raja, P.; Shahul Hameed, M.M.; Shahul Hameed, P.

2004-01-01

The present work reports the distribution of naturally occurring alpha emitting radionuclide 210 Po in the environmental matrices of Koraiyar river. Koraiyar is a seasonal river and it is situated 5 Km West of Tiruchirappalli. Environmental samples such as water, sediment, plankton, weeds (Eichhornia crassipes), crab (Barytelphusa jacguemonti), gastropods (Pila virens and Bellamya dissimilis) and fishes (Anabas testudineus, Catla catla, Clarias batrachus, Channa punctatus, Macrognathus acculeatus, Mystus vittatus and Oreochromis mossambicus) were collected and subjected to the analyses of 210 Po activity. The concentration of 210 Po in water sample and sediment sample was 0.75 mBq/l and 3.1 Bq/Kg respectively. The roots and shoots of aquatic weeds and plankton sample showed concentration of 3.4, 1.2 and 22.2 Bq/Kg respectively. The concentration of 210 Po in crab muscle and exoskeleton was 43.92 Bq/Kg and 11.34 Bq/Kg respectively. In soft tissue of gastropods the 210 Po activity ranged from 38.16 (B. dissimilis) to 88.74 Bq/Kg (P. virens) and 2.9 to 9.45 Bq/Kg in shell. The 210 Po activity in fishes ranged from 8.87 (Macrognathus acculeatus) to 45.29 (Clarias batrachus) Bq/Kg in muscle and 4.76 to 25.09 Bq/Kg in bone. Concentration factor of 210 Po in edible portion of fish from river water ranged from 1.3 x 10 3 to 6.0 x 10 4 . Among the samples analysed P. virens accumulated higher concentrations of 210 Po and it could serve as a bioindicator organism in the absence of any bivalve mollusc. (author)

Dark and bright solitons for the two-dimensional complex modified Korteweg-de Vries and Maxwell-Bloch system with time-dependent coefficient

Science.gov (United States)

Shaikhova, G.; Ozat, N.; Yesmakhanova, K.; Bekova, G.

2018-02-01

In this work, we present Lax pair for two-dimensional complex modified Korteweg-de Vries and Maxwell-Bloch (cmKdV-MB) system with the time-dependent coefficient. Dark and bright soliton solutions for the cmKdV-MB system with variable coefficient are received by Darboux transformation. Moreover, the determinant representation of the one-fold and two-fold Darboux transformation for the cmKdV-MB system with time-dependent coefficient is presented.

A note on the Königs domain of compact composition operators on the Bloch space

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Jones Matthew

2011-01-01

Full Text Available Abstract Let be the unit disk in the complex plane. We define to be the little Bloch space of functions f analytic in which satisfy lim|z|→1 (1 - |z|2|f'(z| = 0. If is analytic then the composition operator Cφ : f ↦ f ∘ φ is a continuous operator that maps into itself. In this paper, we show that the compactness of Cφ , as an operator on , can be modelled geometrically by its principal eigenfunction. In particular, under certain necessary conditions, we relate the compactness of Cφ to the geometry of , where σ satisfies Schöder's functional equation σ ∘ φ = φ'(0σ. 2000 Mathematics Subject Classification: Primary 30D05; 47B33 Secondary 30D45.

Generalized Bloch Theorem for Complex Periodic Potentials - A Powerful Application to Quantum Transport Calculations

International Nuclear Information System (INIS)

Zhang, Xiaoguang; Varga, Kalman; Pantelides, Sokrates T

2007-01-01

Band-theoretic methods with periodically repeated supercells have been a powerful approach for ground-state electronic structure calculations, but have not so far been adapted for quantum transport problems with open boundary conditions. Here we introduce a generalized Bloch theorem for complex periodic potentials and use a transfer-matrix formulation to cast the transmission probability in a scattering problem with open boundary conditions in terms of the complex wave vectors of a periodic system with absorbing layers, allowing a band technique for quantum transport calculations. The accuracy and utility of the method is demonstrated by the model problems of the transmission of an electron over a square barrier and the scattering of a phonon in an inhomogeneous nanowire. Application to the resistance of a twin boundary in nanocrystalline copper yields excellent agreement with recent experimental data

Establishment of a cell line from kidney of seabass, Lates calcarifer (Bloch

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Phromkunthong, W.

2003-01-01

Full Text Available Primary cell culture from caudal fin and kidney of seabass (Lates calcarifer Bloch using tissue explant method were cultured in three different medias with various salt concentrations. Only seabass kidney (SK cells grew well in Leibovitze's-15 medium containing 8 g/l of NaCl supplemented with 10 % fetal bovine serum at an optimum temperature of 25 oC. Over a period of 24 months, SK cells were subcultured over than 75 passages and exhibited epithelial-like cells. The chromosome number of SK cells was 42. The cells were found to be free from bacterial, fungal and mycoplasma contamination. Seabass cells can be kept at -80 oC and/or in liquid nitrogen (-196 oC for at least 24 months with a survival rate of 83.20 and 74.50 %, respectively. Nine fish viruses were tested for their infectivity and this SK cells were susceptible to sand goby virus (SGV, chub reovirus (CRV, snake-head rhabdovirus (SHRV, red seabream iridovirus (RSIV, seabass iridovirus (SIV and grouper iridovirus-2 (GIV-2.

High-Q contacted ring microcavities with scatterer-avoiding “wiggler” Bloch wave supermode fields

Energy Technology Data Exchange (ETDEWEB)

Liu, Yangyang, E-mail: yangyang.liu@colorado.edu; Popović, Miloš A., E-mail: milos.popovic@colorado.edu [Nanophotonic Systems Laboratory, Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309 (United States)

2014-05-19

High-Q ring resonators with contacts to the waveguide core provide a versatile platform for various applications in chip-scale optomechanics, thermo-, and electro-optics. We propose and demonstrate azimuthally periodic contacted ring resonators based on multi-mode Bloch matching that support contacts on both the inner and outer radius edges with small degradation to the optical quality factor (Q). Radiative coupling between degenerate modes of adjacent radial spatial order leads to imaginary frequency (Q) splitting and a scatterer avoiding high-Q “wiggler” supermode field. We experimentally measure Qs up to 258 000 in devices fabricated in a silicon device layer on buried oxide undercladding and up to 139 000 in devices fully suspended in air using an undercut step. Wiggler supermodes are true modes of the microphotonic system that offer additional degrees of freedom in electrical, thermal, and mechanical design.

Dynamics of Peregrine combs and Peregrine walls in an inhomogeneous Hirota and Maxwell-Bloch system

Science.gov (United States)

Wang, Lei; Wang, Zi-Qi; Sun, Wen-Rong; Shi, Yu-Ying; Li, Min; Xu, Min

2017-06-01

Under investigation in this paper is an inhomogeneous Hirota-Maxwell-Bloch (IHMB) system which can describe the propagation of optical solitons in an erbium-doped optical fiber. The breather multiple births (BMBs) are derived with periodically varying group velocity dispersion (GVD) coefficients. Under large periodic modulations in the GVD coefficient of IHMB system, the Peregrine comb (PC) solution is produced, which can be viewed as the limiting case of the BMBs. When the amplitude of the modulation satisfies a special condition, the Peregrine wall (PW) that can be regarded as an intermediate state between rogue wave and PC is obtained. The effects of the third-order dispersion on the spatiotemporal characteristics of PCs and PWs are studied. Our results may be useful for the experimental control and manipulation of the formation of generalized Peregrine rogue waves in inhomogeneous erbium-doped optical fiber.

Resonant absorption in semiconductor nanowires and nanowire arrays: Relating leaky waveguide modes to Bloch photonic crystal modes

Energy Technology Data Exchange (ETDEWEB)

Fountaine, Katherine T., E-mail: kfountai@caltech.edu [Department of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Whitney, William S. [Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Department of Physics, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Atwater, Harry A. [Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Department of Applied Physics and Materials Science, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States)

2014-10-21

We present a unified framework for resonant absorption in periodic arrays of high index semiconductor nanowires that combines a leaky waveguide theory perspective and that of photonic crystals supporting Bloch modes, as array density transitions from sparse to dense. Full dispersion relations are calculated for each mode at varying illumination angles using the eigenvalue equation for leaky waveguide modes of an infinite dielectric cylinder. The dispersion relations along with symmetry arguments explain the selectivity of mode excitation and spectral red-shifting of absorption for illumination parallel to the nanowire axis in comparison to perpendicular illumination. Analysis of photonic crystal band dispersion for varying array density illustrates that the modes responsible for resonant nanowire absorption emerge from the leaky waveguide modes.

Narrow Bloch walls and intrinsic characteristics of the pseudoternary Nd14Fe78-xMnxC8 systems

International Nuclear Information System (INIS)

Xing, F.; Ho, W.W.

1990-01-01

The lattice constants of Nd 14 Fe 78-x Mn x C 8 compounds decrease with the increase of Mn context x and have a minimum at about x=14. The Curie temperature T c decreases linearly and falls off below room temperature beyond x=14. The strong reduction of the saturation magnetization and T c are attributed to the antiparallel alignment of the Mn and Fe atoms moments. The behavior of magnetization and magnetization reversal in the high-Mn-containing samples at low temperature can be interpreted by the narrow domain wall effect. The relationship of the intrinsic coercive force i H c on temperature agrees well with the exponential formula of the narrow Bloch wall

The Bergman spaces, the Bloch space and the pluriharmonic conjugates in the unit ball of Cn

International Nuclear Information System (INIS)

Shi Jihuai.

1989-06-01

It has been proved that if f is holomorphic in the unit ball B of C m , then f is an element of L p (B,dν) if all the functions (1 - |z| 2 ) m (D n f)(z) with |α| = m are in L p (B,dν). This method can only deal with the case of p ≥ 1. In this paper, we give a new approach to prove that the above result holds for all p is an element of (0, ∞). A simple proof about the characterization of the Bloch space will be given. As a by-product of our approach, we generalize a theorem to the unit ball of C m , and use this result to generalize some theorems about the pluriharmonic conjugates to the case 0 < p < 1. 9 refs

The Bloch self-consistently renormalized spin wave approximation and behaviour of some thermodynamic quantities of a Heisenberg ferromagnet in the critical region

International Nuclear Information System (INIS)

Jezewski, W.

1979-01-01

Properties of the Bloch self-consistently renormalized spin wave approximation are analyzed near the zero-field transition temperature Tsub(m). The analysis is carried out on the basis of the application of this approximation to the Heisenberg ferromagnet involving nearest neighbour interaction. Series expansions for the resulting Helmholtz free energy, magnetization, and specific heat in the reduced temperature t=(Tsub(m)-T)/Tsub(m) are derived and the critical exponents β and α' are obtained. The limiting case of infinite spin (the classical limit) is also investigated. (author)

Violation of Bloch's Law That Specifies Reciprocity of Intensity and Duration with Brief Light Flashes

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Ernest Greene

2013-12-01

Full Text Available For more than a century researchers have been reporting that the visual impact of a very brief flash is determined by the quantity of photons that the flash delivers. This has been variously described as the Bunsen-Roscoe Law or Bloch's Law, often specified as reciprocity of intensity × duration. Prior research found no evidence for such reciprocity when microsecond-duration flashes from a light-emitting diode array were used to display the major contours of nameable shapes. The present work tested with flash durations ranging up to 100 ms and also found no reciprocity. This departure from classic principles might be due to the specific range of wavelengths of the light-emitting diodes and to a mesopic level of ambient light, which together would preclude activation of rods. The reciprocity of intensity and duration may only be valid with full dark adaptation and very dim flashes that activate rods.

A size selective porous silicon grating-coupled Bloch surface and sub-surface wave biosensor.

Science.gov (United States)

Rodriguez, Gilberto A; Ryckman, Judson D; Jiao, Yang; Weiss, Sharon M

2014-03-15

A porous silicon (PSi) grating-coupled Bloch surface and sub-surface wave (BSW/BSSW) biosensor is demonstrated to size selectively detect the presence of both large and small molecules. The BSW is used to sense large immobilized analytes at the surface of the structure while the BSSW that is confined inside but near the top of the structure is used to sensitively detect small molecules. Functionality of the BSW and BSSW modes is theoretically described by dispersion relations, field confinements, and simulated refractive index shifts within the structure. The theoretical results are experimentally verified by detecting two different small chemical molecules and one large 40 base DNA oligonucleotide. The PSi-BSW/BSSW structure is benchmarked against current porous silicon technology and is shown to have a 6-fold higher sensitivity in detecting large molecules and a 33% improvement in detecting small molecules. This is the first report of a grating-coupled BSW biosensor and the first report of a BSSW propagating mode. © 2013 Published by Elsevier B.V.

Differential geometric invariants for time-reversal symmetric Bloch-bundles: The “Real” case

International Nuclear Information System (INIS)

De Nittis, Giuseppe; Gomi, Kiyonori

2016-01-01

Topological quantum systems subjected to an even (resp. odd) time-reversal symmetry can be classified by looking at the related “Real” (resp. “Quaternionic”) Bloch-bundles. If from one side the topological classification of these time-reversal vector bundle theories has been completely described in De Nittis and Gomi [J. Geom. Phys. 86, 303–338 (2014)] for the “Real” case and in De Nittis and Gomi [Commun. Math. Phys. 339, 1–55 (2015)] for the “Quaternionic” case, from the other side it seems that a classification in terms of differential geometric invariants is still missing in the literature. With this article and its companion [G. De Nittis and K. Gomi (unpublished)] we want to cover this gap. More precisely, we extend in an equivariant way the theory of connections on principal bundles and vector bundles endowed with a time-reversal symmetry. In the “Real” case we generalize the Chern-Weil theory and we show that the assignment of a “Real” connection, along with the related differential Chern class and its holonomy, suffices for the classification of “Real” vector bundles in low dimensions.

Energies and bounds from perturbative approximations to the Bloch-Horowitz effective Hamiltonian

International Nuclear Information System (INIS)

Darema-Rogers, F.; Vincent, C.M.

1978-01-01

Bloch-Horowitz perturbation theory is applied to the calculation of approximate energies and model-space eigenvectors, for the solvable large-matrix Hamiltonian H used by Pittel, Vincent, and Vergados. Two types of upper and lower bounds to the energies are discussed: moment-theory bounds, obtained by applying moment theory to the terms of perturbation theory, and norm bounds, derived from the expectation E-bar and variance sigma 2 of H with respect to an eigenvector approximated by nth order perturbation theory (n < or = 6). It is shown that lower bounds cannot be constructed unless some fourth-order quantity is known. The upper bounds are generally stricter than the lower bounds. All of the bounds apply even when back-door intruder states cause perturbation theory to diverge; but they lose their rigor and become ''quasibounds'' when there are physical intruders. The moment-theory and norm lower quasibounds always require estimation of a parameter. For the solvable Hamiltonians, it is shown that this can be done quite reliably, and that the resulting quasibounds are tight enough to have some practical utility. The energy-independent effective interaction V is constructed and its errors are displayed and discussed. Finally, a certain [1/2] pseudo-Pade approximant is empirically shown to give energies with a mean absolute error of less than 0.3 MeV in all cases

Cytotoxic and genotoxic affects of acid mine drainage on fish Channa punctata (Bloch).

Science.gov (United States)

Talukdar, B; Kalita, H K; Basumatary, S; Saikia, D J; Sarma, D

2017-10-01

The investigation deals with the effects of Acid Mine Drainage (AMD) of coal mine on fish Channa punctata (Bloch) by examining the incidence of haematological, morphological, histological changes and DNA fragmentation in tissues of C. punctata in laboratory condition. For this study fishes were exposed to 10% of AMD for a period of 30 days. The fusion of the primary and secondary gill lamellae, distortion, loss of alignment, deposition of worn out tissues and mucous on the surface of the lamella in the gills; degeneration of morphological architecture, loss of alignment of tubules, mucous deposition in the kidney; cellular damage, cellular necrosis, extraneous deposition on the surface, pore formation in the liver are some important changes detected by scanning electron microscopy. Fishes of AMD treated group showed gradual significant decrease in TEC, Hb and, increase in TLC and DLC as compared to that of the control. DNA fragmentation observed in kidney of fishes from treated group indicates an intricate pollutant present in the AMD. The high incidence of morphological and histological alterations, haematological changes along with DNA breakage in C. punctata is an evidence of the cytotoxic and genotoxic potential of AMD of coal mines. Copyright © 2017 Elsevier Inc. All rights reserved.

Peces colectados en el río Acandí (Chocó suroeste del Caribe colombiano Peces colectados en el río Acandí (Chocó suroeste del Caribe colombiano

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Alvarez León Ricardo

1991-12-01

Full Text Available Se registra por primera vez la presencia de seis especies de peces colectados en el río Acandí durante la expedición URABA II, en febrero de 1985, tres de los cuales (Citharichtys spilopterus, Achirus lineatus y Sphoeroides testudineus, son nuevos registros para los ríos del Caribe colombiano. Six species of fishes, collected in the river Acandí during expedition URABA II, in February of 1985, are reported for first time, of the wish three (Citharichtys spilopterus, Achirus lineatus y Sphoeroides testudineus, is new report for the rivers of the Colombian Caribbean.

PEMANFAATAN KOLAM PENGENDAP TAMBANG BATUBARA UNTUK BUDIDAYA IKAN LOKAL DALAM KERAMBA

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Asfie Maidie

2016-11-01

Full Text Available Uji coba budidaya dalam keramba telah dilakukan untuk mengetahui kelayakan kolam pengendap tambang batubara untuk areal budidaya ikan bagi masyarakat sekitar apabila kegiatan tambang telah ditutup, serta untuk mengetahui apakah produk ikan yang dihasilkan cukup aman untuk dikonsumsi manusia. Percobaan dilakukan pada bekas kolam pengendap DS2 milik PT KPC, dengan mengunakan 5 buah keramba apung berukuran 3 m x 1 m x 1 m yang dalam setiap keramba ditebar benih dari alam untuk ikan repang (Barbodes schwanenfeldii ukuran rata-rata 20,2 g; puyau (Osteichilus kappenii ukuran 66,1 g; dan mas (Cyprinus carpio ukuran 28,96 g dari pemijahan di laboratorium sebanyak masing-masing 200 ekor, serta pepuyu (Anabas testudineus ukuran rata-rata 41,4 g dari alam sebanyak 50 ekor, udang galah (Macrobrachium rosenbergii ukuran 113,8 g juga dari alam sebanyak 50 ekor. Pakan diberikan secara sampai kenyang (ad libitum. DO, pH, suhu, DHL, dan kekeruhan diukur harian, sedangkan ikan diukur pertumbuhan bobotnya. Setelah dipelihara selama 4 bulan dan memenuhi ukuran konsumsi, ikan dan udang diperiksa kandungan Sb, Se, As, Hg, Mn, Cd, Fe, Cu, Pb, dan Zn. Hasil penelitian menunjukkan bahwa bekas kolam pengendap tambang batubara cukup layak untuk dikembangkan sebagai areal budidaya ikan dengan memberikan pertumbuhan bobot populasi sebesar 570,79% (repang, SR: 95%, 202,57% (puyau, SR: 97%, 573% (mas, SR: 2,5%, 238,92% (udang galah, SR: 10%, 447,10% (pepuyu, SR: 14% dan produknya cukup aman untuk dikonsumsi, dengan kandungan Sb (0,24-2,45 mg/L, rasio terdeteksi dari sample: 100%, Se (0,00-0,06, 57,14%, As (tidak terdeteksi/ttd, Hg (0,00-0,06 mg/L, 50%, Mn (ttd-1,68 mg/L, 14,29%, Cd (ttd, Fe (ttd-5,45 mg/L, 7,14%, Cu (ttd, Pb (ttd, dan Zn (7,82-61,50 mg/L, 100%. The experiment was conducted to study the feasibility of settling or sedimentation pond of coal mining to be used for culturing fish in net cage for local people post  mining activities. Experimental 3 m x 1 m x 1 m

Several Growth Characteristics of an Invasive Cyprinid Fish (Carassius gibelio Bloch, 1782

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Sait BULUT

2013-05-01

Full Text Available Age composition, length-weight relationships, growth, and condition factors of the gibel carp (Carassius gibelio Bloch, 1782 were determined using specimens collected from Seyitler Reservoir between July 2005 to June 2006. A total of 149 gibel carp were observed and examined. The age composition of the samples ranged between I and VII years of age. It has been determined than 82.55% of the obtained samples are comprised of females, 16.11% is comprised of males and 1.34% is comprised of immature. The population is dominated by females able to reproduce gynogenetically. The mean fork lengths and mean weights of the population were 14.8-32.5 cm and 43.1-807.3 g respectively. The length-weight relation were calculated as W = 0.0696 L2.132, r=0.838 for females, for males W = 0.2942 L2.6417 r=0.784 and W = 0.0274 L2.9382, r=0.813 for all samples. The mean Fulton Condition Factor was calculated as 2.342 for females, 2.064 for males and 2.276 for all samples. Age-length and age-weight relations were determined according to von Bertalanffy growth equation formula. Growth parameters of the population were Lt = 48.09 [1-e-0.093(t+0.29], and Wt=2323.62 [1-e-0.093(t+0.29]2.9382. The growth performance index value (Ø´ was computed as 5.37 for all specimens.

The taxonomic status of Japanese threadfin bream Nemipterus japonicus (Bloch, 1791) (Perciformes: Nemipteridae) with a redescription of this species from the south china sea based on morphology and DNA barcodes

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Ning, Ping; Sha, Zhongli; Hebert, Paul D. N.; Russell, Barry

2015-02-01

Because of its importance as a food source, Nemipterus japonicus (Bloch, 1791) (Nemipteridae) or Japanese threadfin bream is the best studied of these taxa, and numerous investigations have examined its fisheries, its biology and biochemistry. Despite such intensive work, the taxonomic status of N. japonicus has never been seriously questioned and it is regarded as a common species, widely distributed throughout the Indo-Western Pacific Ocean. In fact, Bloch's description of the type specimen of N. japonicus has ambiguous collection data and lacks a designation for the type locality, though it is probably Java. In this paper, DNA barcode results based on COI gene support the existence of two geographically separated lineages of the Japanese threadfin bream, both being an Indian Ocean and western Pacific lineage, with 2.7% sequence divergence, and the results indicate a possible existing of some cryptic species. The two lineages also possess a diagnostic difference in their belly color, with specimens in the South China Sea having a silver belly, while those from the Indian Ocean isolate specimen have a yellow coloration. Based upon new collections from the South China Sea, this species from the western Pacific is morphologically redescribed and its details of DNA barcode diversity are shown for the future investigations.

Development of immune functionality in larval and juvenile crimson snapper Lutjanus erythropterus (Bloch 1790

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Ke Cui

2018-05-01

Full Text Available Ontogenetic development of the immune system in crimson snapper (Lutjanus erythropterus Bloch 1790 larvae was histologically and enzymatically studied from hatch to 36 days post-hatch (DPH. Primitive hepatopancreas appeared on 2 DPH and renal tubules started hematopoiesis on 4 DPH. The spleen anlage appeared on 6 DPH and the thymus formed on 14 DPH. Total activities of superoxide dismutase (SOD, catalase (CAT, glutathione peroxidase (GPX and sodium-potassium adenosine triphosphatase (Na+ K+-ATPase gradually increased after hatch, and showed a sharp increase after 29 DPH during the transitional feeding period from Artemia to inert feed. The specific activities of SOD, CAT, and GPX showed a trend of sharp increase and reached the maximum level on 4 DPH when exogenous feeding started, except for Na+ K+-ATPase where the peak occurred on10 DPH. The specific activities of these five enzymes reached the peak during the food transition from rotifers to Artemia, but the total activity of enzymes showed an increasing trend as fish grew. The present study provides new knowledge of the development of functional enzymes relevant to fish larvae immunity, sheds light on the understanding of the change of larval health, and improves hatchery management of crimson snapper. Keywords: Immune system, Enzyme activity, Ontogenetic development, Crimson snapper Lutjanus erythropterus

Morphometric evaluation of the spermatogenesis in trahira Hoplias malabaricus (Bloch (Characiformes, Erythrinidae Avaliação morfométrica da espermatogênese da traíra Hoplias malabaricus (Bloch (Characiformes, Erythrinidae

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Paula M. Bizzott

2007-01-01

Full Text Available The Erythrinidae trahira, Hoplias malabaricus (Bloch, 1794, is widespread throughout South America river basins. We determined Sertoli cell supporting capacity (ratio of primary spermatocytes: Sertoli cells and spermatids: Sertoli cells, meiotic index (ratio of spermatids: primary spermatocytes and the number of spermatogonial mitotic generations of this fish. The fish were captured in the Igarapava reservoir, Grande River, Alto Paraná River basin, Brazil. Testis fragments of three sexually mature trahiras were fixed in 5% buffered glutaraldehyde solution and embedded in glycol methacrylate. Serial sections of 2 and 3 µm in thickness were stained with 0.5% toluidine blue. Histological counts from cysts of primary spermatocytes and spermatids revealed, respectively, 326 ± 99 and 468 ± 73 nuclei of these cells. Sertoli cell supporting capacity was considerably higher for spermatids (113.3 ± 16:1 when compared to primary spermatocytes (71 ± 5:1. Between eight and ten spermatogonial generations were formed to give rise to primary spermatocytes. These values were within the generation range of those already found in freshwater teleosts of external fertilization. Correlation between the number of Sertoli cells and primary spermatocytes per cyst, and Sertoli cells and spermatids per cyst were statistically significant (p A traíra, Hoplias malabaricus (Bloch, 1794, da família Erythrinidae, encontra-se espalhada pelas bacias fluviais da América do Sul. Determinou-se a capacidade de suporte das células de Sertoli (espermatócitos primários: células de Sertoli e espermátides: células de Sertoli, índice meiótico (espermátides: espermatócitos primário e o número de gerações mitóticas de espermatogônias desse peixe. Os indivíduos foram capturados no reservatório de Igarapava, rio Grande, bacia do Alto Paraná, Brasil. Fragmentos dos testículos de três traíras sexualmente maduras foram fixados em glutaraldeído a 5%, e inclu

Suppression of error in qubit rotations due to Bloch-Siegert oscillation via the use of off-resonant Raman excitation

International Nuclear Information System (INIS)

Pradhan, Prabhakar; Cardoso, George C; Shahriar, M S

2009-01-01

The rotation of a quantum bit (qubit) is an important step in quantum computation. The rotation is generally performed using a Rabi oscillation. In a direct two-level qubit system, if the Rabi frequency is comparable to its resonance frequency, the rotating wave approximation is not valid, and the Rabi oscillation is accompanied by the so-called Bloch-Siegert oscillation (BSO) that occurs at twice the frequency of the driving field. One implication of the BSO is that for a given interaction time and Rabi frequency, the degree of rotation experienced by the qubit depends explicitly on the initial phase of the driving field. If this effect is not controlled, it leads to an apparent fluctuation in the rotation of the qubit. Here we show that when an off-resonant lambda system is used to realize a two-level qubit, the BSO is inherently negligible, thus eliminating this source of potential error.

Architecture and Bloch-Maxwell modelling of multi-mJ 100 fs fully-coherent soft X-ray laser based on X-ray CPA

International Nuclear Information System (INIS)

Zeitoun, Ph.; Oliva, E.; Fajardo, M.; Cheriaux, G.; Le, T. T. T.; Li, L.; Pitman, M.; Ros, D.; Sebban, S.; Velarde, P.

2012-01-01

By seeding amplifying plasmas pumped with the so-called Transient collisionnal excitation scheme, the amplified pulse seems to be limited to an energy of several 10's of μJ. Aiming to attain several mJ, we study the seeding of plasma pumped by long laser pulse. Thanks to our time-dependent Maxwell-Bloch code, we demonstrate that direct seeding with femtosecond pulse is inefficient. We also study the amplification of pulse train with the drawback of re-synchronizing the pulses. We proposed and studied the amplification of high harmonic seed stretched by a grating pair, amplified finally compressed. We consider off-axis diffraction on the gratings for maximizing their efficiency. Considering the phase deformation induced by the amplification and the spectral narrowing the final pulse is 230 fs in duration and 5 mJ.

Azimuthal spin-wave excitations in magnetic nanodots over the soliton background: Vortex, Bloch, and Néel-like skyrmions

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Mruczkiewicz, M.; Gruszecki, P.; Krawczyk, M.; Guslienko, K. Y.

2018-02-01

We study azimuthal spin-wave (SW) excitations in a circular ferromagnetic nanodot in different inhomogeneous, topologically nontrivial magnetization states, specifically, vortex, Bloch-type skyrmion, and Néel-type skyrmion states. A continuous transition between these states is realized by gradually changing the out-of-plane magnetic anisotropy and the Dzyaloshinskii-Moriya exchange interaction (DMI), and the corresponding SW spectra are calculated for each state. We observe the lifting of degeneracy of SW mode frequencies and a change in the systematics of frequency levels. The latter effect is induced by the geometric Berry phase, which occurs in SWs localized at the edge of the dot in the vortex state, and vanishes in the skyrmion states. Furthermore, channeling of edge-localized azimuthal SWs and a related large frequency splitting are observed in the skyrmion states. This is attributed to DMI-induced nonreciprocity, while the coupling of the breathing and gyrotropic modes is related to the skyrmion motion. Finally, we demonstrate efficient coupling of the dynamic magnetization to a uniform magnetic field in nanodots of noncircular symmetry in the skyrmion states.

Bloch Surface Waves Biosensors for High Sensitivity Detection of Soluble ERBB2 in a Complex Biological Environment.

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Sinibaldi, Alberto; Sampaoli, Camilla; Danz, Norbert; Munzert, Peter; Sonntag, Frank; Centola, Fabio; Occhicone, Agostino; Tremante, Elisa; Giacomini, Patrizio; Michelotti, Francesco

2017-08-17

We report on the use of one-dimensional photonic crystals to detect clinically relevant concentrations of the cancer biomarker ERBB2 in cell lysates. Overexpression of the ERBB2 protein is associated with aggressive breast cancer subtypes. To detect soluble ERBB2, we developed an optical set-up which operates in both label-free and fluorescence modes. The detection approach makes use of a sandwich assay, in which the one-dimensional photonic crystals sustaining Bloch surface waves are modified with monoclonal antibodies, in order to guarantee high specificity during the biological recognition. We present the results of exemplary protein G based label-free assays in complex biological matrices, reaching an estimated limit of detection of 0.5 ng/mL. On-chip and chip-to-chip variability of the results is addressed too, providing repeatability rates. Moreover, results on fluorescence operation demonstrate the capability to perform high sensitive cancer biomarker assays reaching a resolution of 0.6 ng/mL, without protein G assistance. The resolution obtained in both modes meets international guidelines and recommendations (15 ng/mL) for ERBB2 quantification assays, providing an alternative tool to phenotype and diagnose molecular cancer subtypes.

Microbiological and biochemical changes in pearl spot (Etroplus suratensis Bloch) stored under modified atmospheres.

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Lalitha, K V; Sonaji, E R; Manju, S; Jose, L; Gopal, T K S; Ravisankar, C N

2005-01-01

This study aimed to determine the effect of packaging [air, modified atmosphere (MA)] on microbial growth, sensory and chemical parameters and also on shelf life of fresh pearl spot (Etroplus suratensis Bloch) and on the selection of microbial association. Fresh pearl spot (whole, gutted) were packaged under both 100% air and MAs (40%CO(2)/60% O(2), 50%CO(2)/50%O(2), 60% CO(2)/40%O(2), 70% CO(2)/30% O(2) and 40% CO(2)/30% O(2)/30% N(2)) and stored at 0 degrees C. Microbial growth (counts of total aerobic bacteria, H(2)S-producing bacteria, Lactic acid bacteria, Brochothrix thermosphacta, yeast and mould), chemical spoilage indicators (pH, total volatile basic nitrogen) and sensory characteristics were monitored. Microbial changes in Pearl spot packed under 100% air and 40% CO(2)/30%O(2)/30% N(2) were similar. The total volatile basic nitrogen values increased, but the values never exceeded the acceptability limit of 25 mg 100 g(-1). MA 60% CO(2) : 40%O(2) was found to be better with a shelf life of 21 days whereas air stored samples had a shelf-life of 12-14 days only. Storage of pearl spot under MAs 60% CO(2) : 40%O(2) is a promising method to extend shelf-life. Longer shelf life expands the market potential of pearl spot and reduces waste during distribution and retail display.

Anachronism in the writing of History: ¿Error or Possibility? Some reflections about the concept of time in Carlo Ginzburg, Marc Bloch and Georges Didi-Huberman

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Maria Eugenia Chaves Maldonado

2016-01-01

Full Text Available In his unfinished and posthumously published book Apologie pour l’histoire, Marc Bloch bestowed on future historians a seminal legacy of critical reflections on the concept of time as the object of historical analysis. During the last decades, the concept of time in History has experienced a renewed interest by professional historians, in particular in reference to the category of anachronism. The Italian historian Carlo Ginzburg and the French art historian Georges Didi-Huberman are among those engaged in this debate. This article offers a reading of two works by these historians with the purpose of underlying the fundamental influence that Marc Bloch’s ideas on time had in Ginzburg and Didi-Hubermans’ critical interventions.

The peripheral olfactory organ in the Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801

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Laura Ghigliotti

2015-11-01

Full Text Available The Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801 is the largest predatory fish in Arctic waters. The socio-economic significance of Greenland shark is demonstrated by its impact on the fishing cultures in Greenland, Scandinavia and Iceland for centuries. The fundamental biology and ecological role of Greenland shark, on the other hand, is virtually unknown. Although knowledge of its life history is limited, increasing evidence indicates that the Greenland shark may undertake long-distance migrations and perform vertical movements from the surface to the deep sea. It is an omnivorous species feeding on carrion and a wide variety of pelagic and bottom-dwelling organisms ranging from invertebrates to mammals, and including active species such as fishes and seals. Accordingly, Greenland shark should be recognized as a top predator, with a strong potential to influence the trophic dynamics of the Arctic marine ecosystem. The sensory biology of Greenland shark is scarcely studied, and considering the importance of olfaction in chemoreception, feeding and other behavioral traits, we examined the architecture of the peripheral olfactory organ where olfactory cues are received from the environment – the olfactory rosette. The structural organization of the olfactory rosette, in terms of histological features of the sensory epithelium, number of primary lamellae and total sensory surface area, provides a first proxy of the olfactory capability of Greenland shark. Based on own results and published studies, the overall morphology of the olfactory rosette is viewed in context of the functional and trophic ecology among other elasmobranch species.

Magnetic susceptibility of Dirac fermions, Bi-Sb alloys, interacting Bloch fermions, dilute nonmagnetic alloys, and Kondo alloys

Energy Technology Data Exchange (ETDEWEB)

Buot, Felix A., E-mail: fbuot@gmu.edu [Computational Materials Science Center, George Mason University, Fairfax, VA 22030 (United States); TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines); C& LB Research Institute, Carmen, Cebu 6005 (Philippines); Otadoy, Roland E.S.; Rivero, Karla B. [TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines)

2017-03-01

Wide ranging interest in Dirac Hamiltonian is due to the emergence of novel materials, namely, graphene, topological insulators and superconductors, the newly-discovered Weyl semimetals, and still actively-sought after Majorana fermions in real materials. We give a brief review of the relativistic Dirac quantum mechanics and its impact in the developments of modern physics. The quantum band dynamics of Dirac Hamiltonian is crucial in resolving the giant diamagnetism of bismuth and Bi-Sb alloys. Quantitative agreement of the theory with the experiments on Bi-Sb alloys has been achieved, and physically meaningful contributions to the diamagnetism has been identified. We also treat relativistic Dirac fermion as an interband dynamics in uniform magnetic fields. For the interacting Bloch electrons, the role of translation symmetry for calculating the magnetic susceptibility avoids any approximation to second order in the field. The expressions for magnetic susceptibility of dilute nonmagnetic alloys give a firm theoretical foundation of the empirical formulas used in fitting experimental results. The unified treatment of all the above calculations is based on the lattice Weyl-Wigner formulation of discrete phase-space quantum mechanics. For completeness, the magnetic susceptibility of Kondo alloys is also given since Dirac fermions in conduction band and magnetic impurities exhibit Kondo effect.

Time-dependent Bloch-Maxwell modelling of 1 mJ, 200 fs seeded soft x-ray laser

International Nuclear Information System (INIS)

Zeitoun, Ph.; Oliva, E.; Fajardo, M.; Velarde, P.; Ros, D.; Sebban, S.

2010-01-01

Complete text of publication follows. Seeding of high harmonic generation in a soft x-ray plasma amplifier has been first proposed and tested by T. Ditmire and collaborators. The experiment demonstrated low amplification (*2), with a very strong background coming from the soft x-ray laser ASE. Later seeding experiments reached very high amplification factors (up to 600) in both gas (Ph. Zeitoun et al.) and solid amplifiers (Wang et at.). Surprisingly, solid amplifiers extracted less energy (90 nJ) than gas amplifier (∼ 1 μJ) with equivalent pump energy. We recently demonstrated that 50-100 μJ is achievable with adequate plasma tailoring. However, this energy is still low as compared to the 10 mJ per pulse demonstrated on the ASE soft x-ray laser running at PALS facility (Czech Republic). In order to model the seeding process of PALS soft x-ray laser, we developed a time-dependent Bloch-Maxwell model that solves coherently the pumping, amplification and saturation processes. We demonstrated that direct seeding, with femtosecond pulse, a soft x-ray plasma amplifier having gain duration of several 100s of picosecond cannot extract the stored energy keeping the output beam energy in the 100 μJ range. We proposed and fully modelled a new seeding scheme that allows to achieve 10 mJ, 200 fs soft x-ray laser.

Evaluation of butachlor for control of some submerged macrophytes along with its impact on biotic components of freshwater system

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A. Chattopadhyay, S. Adhikari, S. P. Adhikary, S. Ayyappan

2006-04-01

Full Text Available In this investigation, the efficacy of the herbicide butachlor, (N-butoxymethyl-2 chloro-21, 61 diethyl acetanilide was tested against few common submerged macrophytes namely Hydrilla (Hydrilla verticillata (L. Royale, Najas (Najas minor All., Nechamandra (Nechamandra alternifolia (Roxb. Thwaites and Ottelia (Ottelia alismoides (L. Pers. of freshwater fish ponds. Almost complete decay of Hydrilla, Nechamandra and Ottelia was achieved at 7.5 L of active ingredient/ha/m butachlor within 15 days while the herbicide showed no negative effect on Najas. However at the same concentration of butachlor, total mortality of zooplankton and water fern Azolla (Azolla caroliniana Lamarck occurred within seven days. In case of few freshwater fish species like Rohu (Labeo rohita, Channa (Channa punctatus, Anabas (Anabas testitudineus and Heteropneustes (Heteropneustes fossilis, total mortality occurred upto 90 days after application of the same dose of butachlor but fish survived beyond 120 days of herbicide application indicating degradation of the herbicides.

Functional roles of Na+/K+-ATPase in active ammonia excretion and seawater acclimation in the giant mudskipper, Periophthalmodon schlosseri

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Chew, Shit F.; Hiong, Kum C.; Lam, Sock P.; Ong, Seow W.; Wee, Wei L.; Wong, Wai P.; Ip, Yuen K.

2014-01-01

The giant mudskipper, Periophthalmodon schlosseri, is an amphibious fish that builds burrows in the mudflats. It can actively excrete ammonia through its gills, and tolerate high environmental ammonia. This study aimed to examine the effects of seawater (salinity 30; SW) acclimation and/or environmental ammonia exposure on the kinetic properties of Na+/K+-ATPase (Nka) from, and mRNA expression and protein abundance of nka/Nka α–subunit isoforms in, the gills of P. schlosseri pre-acclimated to slightly brackish water (salinity 3; SBW). Our results revealed that the Nka from the gills of P. schlosseri pre-acclimated to SBW for 2 weeks had substantially higher affinity to (or lower Km for) K+ than NH+4, and its affinity to NH+4 decreased significantly after 6-days exposure to 75 mmol l−1 NH4Cl in SBW. Hence, Nka transported K+ selectively to maintain intracellular K+ homeostasis, instead of transporting NH+4 from the blood into ionocytes during active NH+4 excretion as previously suggested. Two nkaα isoforms, nkaα1 and nkaα3, were cloned and sequenced from the gills of P. schlosseri. Their deduced amino acid sequences had K+ binding sites identical to that of Nkaα1c from Anabas testudineus, indicating that they could effectively differentiate K+ from NH+4. Six days of exposure to 75 mmol l−1 NH4Cl in SBW, or to SW with or without 50 mmol l−1 NH4Cl led to significant increases in Nka activities in the gills of P. schlosseri. However, a significant increase in the comprehensive Nkaα protein abundance was observed only in the gills of fish exposed to 50 mmol l−1 NH4Cl in SW. Hence, post-translational modification could be an important activity modulator of branchial Nka in P. schlosseri. The fast modulation of Nka activity and concurrent expressions of two branchial nkaα isoforms could in part contribute to the ability of P. schlosseri to survive abrupt transfer between SBW and SW or abrupt exposure to ammonia. PMID:24795653

Functional roles of Na+/K+-ATPase in active ammonia excretion and seawater acclimation in the giant mudskipper, Periophthalmodon schlosseri

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Shit F Chew

2014-04-01

Full Text Available The giant mudskipper, Periophthalmodon schlosseri, is an amphibious fish that builds burrows in the mudflats. It can actively excrete ammonia through its gills, and tolerate high environmental ammonia. This study aimed to examine the effects of seawater (salinity 30; SW acclimation and/or environmental ammonia exposure on the kinetic properties of Na+/K+-ATPase (Nka from, and mRNA expression and protein abundance of nka/Nka α–subunit isoforms in, the gills of P. schlosseri pre-acclimated to slightly brackish water (salinity 3; SBW. Our results revealed that the Nka from the gills of P. schlosseri pre-acclimated to SBW for 2 wk had substantially higher affinity to (or lower Km for K+ than NH4+, and its affinity to NH4+ decreased significantly after 6-d exposure to 75 mmol l-1 NH4Cl in SBW. Hence, Nka transported K+ selectively to maintain intracellular K+ homeostasis, instead of transporting NH4+ from the blood into ionocytes during active NH4+ excretion as previously suggested. Two nkaα isoforms, nkaα1 and nkaα3, were cloned and sequenced from the gills of P. schlosseri. Their deduced amino acid sequences had K+ binding sites identical to that of Nkaα1c from Anabas testudineus, indicating that they could effectively differentiate K+ from NH4+. Six days of exposure to 75 mmol l-1 NH4Cl in SBW, or to SW with or without 50 mmol l-1 NH4Cl led to significant increases in Nka activities in the gills of P. schlosseri. However, a significant increase in the comprehensive Nkaα protein abundance was observed only in the gills of fish exposed to 50 mmol l-1 NH4Cl in SW. Hence, post-translational modification could be an important activity modulator of branchial Nka in P. schlosseri. The fast modulation of Nka activity and concurrent expressions of two branchial nkaα isoforms could in part contribute to the ability of P. schlosseri to survive abrupt transfer between SBW and SW or abrupt exposure to ammonia.

Fish condensate as effective replacer of fish meal protein in diet for striped snakehead, Channa striata (Bloch).

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Wattanakul, Wattana; Wattanakul, Uraiwan; Thongprajukaew, Karun; Muenpo, Chutchawan

2017-02-01

The optimal protein replacement of fish meal (FM) by fish condensate (FC) was investigated in striped snakehead, Channa striata (Bloch) (1.78 ± 0.02 g initial weight). The FM-based diet (0FC) was replaced by substituting protein from FC for 100 (100FC), 200 (200FC), 300 (300FC), 400 (400FC), 500 (500FC) or 600 (600FC) g kg -1 of the FM, and a commercial diet (CD) for carnivorous fish was included for comparison. The experiment was conducted indoors under completely randomized design (8 treatments × 3 replications × 60 fish per pond) over a 6-month trial. There were no significant differences in water quality during the experiment. The fish fed with 500FC had superior growth performance and feed utilization. This dietary treatment gave similar levels to all observed specific activities of digestive enzymes as did baseline 0FC. Survival, carcass composition, hematological parameters and liver histopathology were not negatively impacted by this protein replacement level. Economic analysis also supports the use of this by-product as a potent protein replacer in striped snakehead diet. Findings from the current study indicate that a 500 g kg -1 protein replacement of FM by FC is near optimal for striped snakehead, and similar use of it in the aquafeed of other species appears worth further studies.

Dynamics of Bloch oscillating transistor near bifurcation threshold and its applicability for common mode rejection capability of a differential pair BOT

Science.gov (United States)

Sarkar, Jayanta; Puska, Antti; Hassel, Juha; Hakonen, Pertti

2014-03-01

Bloch oscillating transistor (BOT) is mesoscopic current amplier based on a combination of a Josephson junction or a squid connected with a large resistor and a NIS junction. We have studied the dynamics of BOT near the bifurcation threshold. This is an important feature for an amplifier as this can be utilized to improve its performance characteristics. We have measured the I - V characteristics of the BOT with different base currents (IB) over a wide range of Josephson coupling energies (EJ) . The current gain (β) is found to be increasing with increasing IB and eventually diverging. We have found a record large β = 50 in our experiment. In order to determine the common mode rejection ratio (CMRR) of a differential pair BOT we have used two BOTs fabricated on the same chip. The common mode port is connected to the bases of the two BOTs and fed with varying voltages; simultaneously emitter currents of the two BOTs are recorded. In our experiment we found a 20dB of CMRR.

Influence of in-plane field on the stability of vertical Bloch lines in the walls of OHB at various bias fields

International Nuclear Information System (INIS)

Guo, G.X.; Wang, L.N.; Zhen, C.M.; Nie, X.F.

2006-01-01

The stability of vertical Bloch line (VBL) chains subjected to in-plane field (H ip ) was statistically studied for the ordinary hard bubbles (OHB) in garnet bubble films at various bias fields (H b ). The dumbbell domains were also investigated. We found that (H ip (1) ) IID ip (1) ) ID ip (1) ) OHB and (H ip (2) ) IID =(H ip (2) ) ID =(H ip (2) ) OHB when keeping H b unchanged. With the increasing of H b , the in-plane field H ip (1) , H ip * and H ip (2) all decrease, while the in-plane field range [H ip (1) , H ip * ] and [H ip (1) , H ip (2) ] become narrower. Here, H ip (1) is the initial critical in-plane field where VBLs in the walls of three types of hard domains are annihilated, H ip * stands for the in-plane field where the retention rate of three types of hard domains R reduces to zero, and H ip (2) is the lowest in-plane field where VBLs in their corresponding hard domains are annihilated completely

Diploposthe laevis (Bloch Jacobi (Eucestoda, Hymenolepididae from Netta peposaca (Vieillot (Aves: Anatidae: first record for the Neotropical Region and a new host Diploposthe laevis (Bloch Jacobi (Eucestoda: Hymenolepididae em Netta peposaca (Vieillot (Aves, Anatidae: primeiro registro para Região Neotropical e novo hospedeiro

Directory of Open Access Journals (Sweden)

Eliane F. da Silveira

2008-03-01

Full Text Available One hundred eight rosy-billed pochards, Netta peposaca (Vieillot, 1816, collected in Brazil and Argentina were examined for endoparasites. Collection sites included the municipalities of Santa Vitória do Palmar and Jaguarão, Rio Grande do Sul State, Brazil (wintering site and Alvear, Corrientes Province, northern Argentina (nesting site. Birds were frozen in dry ice after collection. During necropsy they were categorized according to sex and maturation, either adult or juvenile. The cestode Diploposthe laevis (Bloch Jacobi, 1896 was found (prevalence 68.5%, mean infection was 2. The mean prevalence of D. laevis in Alvear (25.9% was higher than found in Jaguarão and Santa Vitória do Palmar, Rio Grande do Sul (19%, and could be related to the nesting site and to the period when the birds may ingest a higher amount of food. This is the first record of a species of the genus Diploposthe in anatideans from South America, and the first record of the species in N. peposaca. Details of the cirrus pouch and vagina were described based on histological sections.Com o objetivo de conhecer a helmintofauna do marrecão, Netta peposaca (Vieillot, 1816, na América do Sul, 108 aves foram amostradas. Os pontos de captura foram os municípios de Santa Vitória do Palmar e Jaguarão, no Estado do Rio Grande do Sul, sul do Brasil (pólo de invernia, e em Alvear, Província de Corrientes, região norte da Argentina (pólo de nidificação, entre 2002 e 2004. As aves foram congeladas em gelo seco logo após o abate. Durante o procedimento de necropsia tiveram o sexo identificado, e foram classificadas de acordo com estado de maturação sexual, em juvenil e adulto. O cestóide Diploposthe laevis (Bloch Jacobi, 1896 foi encontrado com prevalência média de 68,5% e intensidade média de infecção de dois espécimes por hospedeiro. A prevalência média de D. laevis em Alvear (25,9% foi maior do que a encontrada em Jaguarão e Santa Vitória do Palmar, Rio Grande

Web-based description of the space radiation environment using the Bethe-Bloch model

Science.gov (United States)

Cazzola, Emanuele; Calders, Stijn; Lapenta, Giovanni

2016-01-01

Space weather is a rapidly growing area of research not only in scientific and engineering applications but also in physics education and in the interest of the public. We focus especially on space radiation and its impact on space exploration. The topic is highly interdisciplinary, bringing together fundamental concepts of nuclear physics with aspects of radiation protection and space science. We give a new approach to presenting the topic by developing a web-based application that combines some of the fundamental concepts from these two fields into a single tool that can be used in the context of advanced secondary or undergraduate university education. We present DREADCode, an outreach or teaching tool to rapidly assess the current conditions of the radiation field in space. DREADCode uses the available data feeds from a number of ongoing space missions (ACE, GOES-13, GOES-15) to produce a first order approximation of the radiation dose an astronaut would receive during a mission of exploration in deep space (i.e. far from the Earth’s shielding magnetic field and from the radiation belts). DREADCode is based on an easy-to-use GUI interface available online from the European Space Weather Portal (www.spaceweather.eu/dreadcode). The core of the radiation transport computation to produce the radiation dose from the observed fluence of radiation observed by the spacecraft fleet considered is based on a relatively simple approximation: the Bethe-Bloch equation. DREADCode also assumes a simplified geometry and material configuration for the shields used to compute the dose. The approach is approximate and sacrifices some important physics on the altar of rapid execution time, which allows a real-time operation scenario. There is no intention here to produce an operational tool for use in space science and engineering. Rather, we present an educational tool at undergraduate level that uses modern web-based and programming methods to learn some of the most important

Web-based description of the space radiation environment using the Bethe–Bloch model

International Nuclear Information System (INIS)

Cazzola, Emanuele; Lapenta, Giovanni; Calders, Stijn

2016-01-01

Space weather is a rapidly growing area of research not only in scientific and engineering applications but also in physics education and in the interest of the public. We focus especially on space radiation and its impact on space exploration. The topic is highly interdisciplinary, bringing together fundamental concepts of nuclear physics with aspects of radiation protection and space science. We give a new approach to presenting the topic by developing a web-based application that combines some of the fundamental concepts from these two fields into a single tool that can be used in the context of advanced secondary or undergraduate university education. We present DREADCode, an outreach or teaching tool to rapidly assess the current conditions of the radiation field in space. DREADCode uses the available data feeds from a number of ongoing space missions (ACE, GOES-13, GOES-15) to produce a first order approximation of the radiation dose an astronaut would receive during a mission of exploration in deep space (i.e. far from the Earth’s shielding magnetic field and from the radiation belts). DREADCode is based on an easy-to-use GUI interface available online from the European Space Weather Portal (www.spaceweather.eu/dreadcode). The core of the radiation transport computation to produce the radiation dose from the observed fluence of radiation observed by the spacecraft fleet considered is based on a relatively simple approximation: the Bethe–Bloch equation. DREADCode also assumes a simplified geometry and material configuration for the shields used to compute the dose. The approach is approximate and sacrifices some important physics on the altar of rapid execution time, which allows a real-time operation scenario. There is no intention here to produce an operational tool for use in space science and engineering. Rather, we present an educational tool at undergraduate level that uses modern web-based and programming methods to learn some of the most

Multiple Bloch surface waves in visible region of light at the interfaces between rugate filter/rugate filter and rugate filter/dielectric slab/rugate filter

Science.gov (United States)

Ullah Manzoor, Habib; Manzoor, Tareq; Hussain, Masroor; Manzoor, Sanaullah; Nazar, Kashif

2018-04-01

Surface electromagnetic waves are the solution of Maxwell’s frequency domain equations at the interface of two dissimilar materials. In this article, two canonical boundary-value problems have been formulated to analyze the multiplicity of electromagnetic surface waves at the interface between two dissimilar materials in the visible region of light. In the first problem, the interface between two semi-infinite rugate filters having symmetric refractive index profiles is considered and in the second problem, to enhance the multiplicity of surface electromagnetic waves, a homogeneous dielectric slab of 400 nm is included between two semi-infinite symmetric rugate filters. Numerical results show that multiple Bloch surface waves of different phase speeds, different polarization states, different degrees of localization and different field profiles are propagated at the interface between two semi-infinite rugate filters. Having two interfaces when a homogeneous dielectric layer is placed between two semi-infinite rugate filters has increased the multiplicity of electromagnetic surface waves.

Optimal cloning of arbitrary mirror-symmetric distributions on the Bloch sphere: a proposal for practical photonic realization

International Nuclear Information System (INIS)

Bartkiewicz, Karol; Miranowicz, Adam

2012-01-01

We study state-dependent quantum cloning that can outperform universal cloning (UC). This is possible by using some a priori information on a given quantum state to be cloned. Specifically, we propose a generalization and optical implementation of quantum optimal mirror phase-covariant cloning, which refers to optimal cloning of sets of qubits of known modulus of the expectation value of Pauli's Z operator. Our results can be applied to cloning of an arbitrary mirror-symmetric distribution of qubits on the Bloch sphere including in special cases UC and phase-covariant cloning. We show that the cloning is optimal by adapting our former optimality proof for axisymmetric cloning (Bartkiewicz and Miranowicz 2010 Phys. Rev. A 82 042330). Moreover, we propose an optical realization of the optimal mirror phase-covariant 1→2 cloning of a qubit, for which the mean probability of successful cloning varies from 1/6 to 1/3 depending on prior information on the set of qubits to be cloned. The qubits are represented by polarization states of photons generated by the type-I spontaneous parametric down-conversion. The scheme is based on the interference of two photons on an unbalanced polarization-dependent beam splitter with different splitting ratios for vertical and horizontal polarization components and the additional application of feedforward by means of Pockels cells. The experimental feasibility of the proposed setup is carefully studied including various kinds of imperfections and losses. Moreover, we briefly describe two possible cryptographic applications of the optimal mirror phase-covariant cloning corresponding to state discrimination (or estimation) and secure quantum teleportation.

Solitons and rogue waves for a higher-order nonlinear Schroedinger-Maxwell-Bloch system in an erbium-doped fiber

International Nuclear Information System (INIS)

Su, Chuan-Qi; Gao, Yi-Tian; Yu, Xin; Xue, Long; Aviation Univ. of Air Force, Liaoning

2015-01-01

Under investigation in this article is a higher-order nonlinear Schroedinger-Maxwell-Bloch (HNLS-MB) system for the optical pulse propagation in an erbium-doped fiber. Lax pair, Darboux transformation (DT), and generalised DT for the HNLS-MB system are constructed. Soliton solutions and rogue wave solutions are derived based on the DT and generalised DT, respectively. Properties of the solitons and rogue waves are graphically presented. The third-order dispersion parameter, fourth-order dispersion parameter, and frequency detuning all influence the characteristic lines and velocities of the solitons. The frequency detuning also affects the amplitudes of solitons. The separating function has no effect on the properties of the first-order rogue waves, except for the locations where the first-order rogue waves appear. The third-order dispersion parameter affects the propagation directions and shapes of the rogue waves. The frequency detuning influences the rogue-wave types of the module for the measure of polarization of resonant medium and the extant population inversion. The fourth-order dispersion parameter impacts the rogue-wave interaction range and also has an effect on the rogue-wave type of the extant population inversion. The value of separating function affects the spatial-temporal separation of constituting elementary rogue waves for the second-order and third-order rogue waves. The second-order and third-order rogue waves can exhibit the triangular and pentagon patterns under different choices of separating functions.

Mudança na dieta da traíra Hoplias malabaricus (Bloch (Erythrinidae, Characiformes em lagoas da bacia do rio Doce devido à introdução de peixes piscívoros Diet changes of the trahira Hoplias malabaricus (Bloch (Erythrinidae, Characiformes due to piscivorous introductions in Rio Doce valley lakes

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Paulo dos Santos Pompeu

2001-12-01

Full Text Available Two piscivorous fishes, peacock bass (Cichla monoculus Spix & Agassiz, 1831 (Perciformes and piranha (Pygocentrus nattereri Kner, 1860 (Characiformes, were introduced in some Rio Doce valley lakes (19º50'S, 42º40'W for sport fisheries enhancement. As a consequence, small individuals and species were practically vanished in the host lakes. In this study, the effects of peacock bass and piranha introductions on the diet of a native piscivorous fish, the trahira - Hoplias malabaricus (Bloch, 1794 are presented. Trahira's diet from three lakes were was compared with the stomach contentsdiet of trahira's living in another between three lakes with and three withoutstocked with the piscivorous species peacock bass and piranha. In the lakes with introduced fishes species, the consumption of fish was significantly smaller and this food item have been this item partly replaced by aquatic invertebrates. This shift on of trahira's diet to the low abundance of its original prey, is attributed to the small fishes. This diet plasticity adaptative capacity he diet plasticity detected for trahira might be allowing its maintenance in the lakes with peacock bass and piranha.

An Update on the Invasion of Weakfish Cynoscion regalis (Bloch & Schneider, 1801 (Actinopterygii: Sciaenidae into Europe

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Pedro Morais

2017-10-01

Full Text Available New information on weakfish introduction vectors, its invasive status, distribution, and use as a fishing resource arose after the publication of “The transatlantic introduction of weakfish Cynoscion regalis (Bloch & Schneider, 1801 (Sciaenidae, Pisces into Europe” by Morais and Teodósio (2016. Currently, the first known report of weakfish in Europe dates back to September 2009, with a specimen captured in the Schelde estuary (Belgium/The Netherlands. This fact suggests that weakfish could have been introduced into Europe via multiple and independent ballast water introduction events, and not through a point-source introduction event with subsequent dispersion as previously hypothesized. It is also unlikely that Schelde weakfish migrated southwards to colonize Iberian aquatic ecosystems. Weakfish have established a population in the Gulf of Cádiz region and have already reached an invasive status in the Sado estuary (Portugal. Weakfish were also captured in several other locations along the Portuguese coast, including the Tagus and Mira estuaries at least since 2013 or 2014, and the Ria Formosa lagoon in 2017. Tagus anglers caught weakfish specimens of ~1 kg and ~40 cm in November 2016, which corresponds to fish of 3+ years of age in the native range. The presence of weakfish in the Tagus estuary is still fairly unknown to local anglers. Sado weakfish has already been sold in local fish markets in southern Portugal for 3 to 10 € kg−1. However, we consider that the weakfish sale price is underrated in comparison with other wild species (e.g., meagre, seabass, gilthead seabream. Increasing sale price will convince fishers to use weakfish as a new fishing resource; however, it is necessary to promote the species among consumers and evaluate consumers’ preference in respect to other species. A putative biological threat might turn into a new valuable fishing resource by implementing adequate management solutions.

Characterization of anomalous relaxation using the time-fractional Bloch equation and multiple echo T2 *-weighted magnetic resonance imaging at 7 T.

Science.gov (United States)

Qin, Shanlin; Liu, Fawang; Turner, Ian W; Yu, Qiang; Yang, Qianqian; Vegh, Viktor

2017-04-01

To study the utility of fractional calculus in modeling gradient-recalled echo MRI signal decay in the normal human brain. We solved analytically the extended time-fractional Bloch equations resulting in five model parameters, namely, the amplitude, relaxation rate, order of the time-fractional derivative, frequency shift, and constant offset. Voxel-level temporal fitting of the MRI signal was performed using the classical monoexponential model, a previously developed anomalous relaxation model, and using our extended time-fractional relaxation model. Nine brain regions segmented from multiple echo gradient-recalled echo 7 Tesla MRI data acquired from five participants were then used to investigate the characteristics of the extended time-fractional model parameters. We found that the extended time-fractional model is able to fit the experimental data with smaller mean squared error than the classical monoexponential relaxation model and the anomalous relaxation model, which do not account for frequency shift. We were able to fit multiple echo time MRI data with high accuracy using the developed model. Parameters of the model likely capture information on microstructural and susceptibility-induced changes in the human brain. Magn Reson Med 77:1485-1494, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Morphological, histological and molecular characterization of Myxobolus kingchowensis and Thelohanellus cf. sinensis infecting gibel carp Carassius auratus gibelio (Bloch, 1782).

Science.gov (United States)

Zhang, Bo; Zhai, Yanhua; Gu, Zemao; Liu, Yang

2018-06-26

A Myxobolus species and a Thelohanellus species infecting Carassius auratus gibelio (Bloch, 1782) were redescribed by their morphological, histological and molecular characterization. In the present study, the Myxobolus species infecting the muscle was identified as Myxobolus kingchowensis Chen et Ma, 1998 by the morphological and molecular data. Histologically, mature spores of M. kingchowensis were observed in the intercellular and connective tissue of muscle, though the plasmodia were not found. In addition, scattered spores also occurred in the intercellular of haematopoietic cells, intraepithelial of the renal tubules and interior of the melano-macrophage centres. Phylogenetic analysis showed that M. kingchowensis clustered in the clade of muscle-infecting Myxobolus species, further supporting muscle as the infection site of M. kingchowensis. The present Thelohanellus species infecting the gills was identified conspecific as Thelohanellus sinensis reported in Sun (2006) (mark it as T. sinensis-Sun)based on spore morphology, biological traits (host specificity and organ specificity), and molecular data. However, compared with the original description of T. sinensis Chen et Hsieh, 1960, the present Thelohanellus species and T. sinensis-Sun both infecting the gills of gibel carp are distinguishable from the original description in the host and infection site, which made the validity of T. sinensis-Sun dubious. Due to the absence of molecular data in the original description of T. sinensis, we suggest marking the present species and T. sinensis-Sun as T. cf. sinensis to avoid the confusion until T. sinensis is obtained from the type host and type infection site.

The DD Cold Fusion-Transmutation Connection

Science.gov (United States)

Chubb, Talbot A.

2005-12-01

LENR theory must explain dd fusion, alpha-addition transmutations, radiationless nuclear reactions, and three-body nuclear particle reactions. Reaction without radiation requires many-body D Bloch+ periodicity in both location and internal structure dependencies. Electron scattering leads to mixed quantum states. The radiationless dd fusion reaction is 2-D Bloch+ -> {}4 He Bloch2+. Overlap between {}4 He Bloch2+ and surface Cs leads to alpha absorption. In the Iwamura et al. studies active deuterium is created by scattering at diffusion barriers.

Weighted composition operators from Bergman-type spaces into ...

Indian Academy of Sciences (India)

Weighted composition operators from Bergman-type spaces into Bloch spaces and little. Bloch spaces are characterized by function theoretic properties of their inducing maps. Keywords. Weighted composition operator; Bergman-type space; Bloch space. 1. Introduction. Let D be the open unit disk in the complex plane C.

Detection of cyprinid herpesvirus 2 in peripheral blood cells of silver crucian carp, Carassius auratus gibelio (Bloch), suggests its potential in viral diagnosis.

Science.gov (United States)

Wang, H; Xu, Lj; Lu, Lq

2016-02-01

Epidemics caused by cyprinid herpesvirus 2 (CyHV-2) in domestic cyprinid species have been reported in both European and Asian countries. Although the mechanisms remain unknown, acute CyHV-2 infections generally result in high mortality, and the surviving carps become chronic carriers displaying no external clinical signs. In this study, in situ hybridization analysis showed that CyHV-2 tended to infect peripheral blood cells during either acute or chronic infections in silver crucian carp, Carassius auratus gibelio (Bloch). Laboratory challenge experiments coupled with real-time PCR quantification assays further indicated that steady-state levels of the viral genomic copy number in fish serum exhibited a typical 'one-step' growth curve post-viral challenge. Transcriptional expression of open reading frames (ORF) 121, which was selected due to its highest transcriptional levels in almost all tested tissues, was monitored to represent the replication kinetics of CyHV-2 in peripheral blood cells. Similar kinetic curve of active viral gene transcription in blood cells was obtained as that of serum viral load, indicating that CyHV-2 replicated in peripheral blood cells as well as in other well-characterized tissues. This study should pave the way for designing non-invasive and cost-effective serum diagnostic methods for quick detection of CyHV-2 infection. © 2015 John Wiley & Sons Ltd.

Natural outbreak of Streptococcus agalactiae (GBS) infection in wild giant Queensland grouper, Epinephelus lanceolatus (Bloch), and other wild fish in northern Queensland, Australia.

Science.gov (United States)

Bowater, R O; Forbes-Faulkner, J; Anderson, I G; Condon, K; Robinson, B; Kong, F; Gilbert, G L; Reynolds, A; Hyland, S; McPherson, G; Brien, J O'; Blyde, D

2012-03-01

Ninety-three giant Queensland grouper, Epinephelus lanceolatus (Bloch), were found dead in Queensland, Australia, from 2007 to 2011. Most dead fish occurred in northern Queensland, with a peak of mortalities in Cairns in June 2008. In 2009, sick wild fish including giant sea catfish, Arius thalassinus (Rüppell), and javelin grunter, Pomadasys kaakan (Cuvier), also occurred in Cairns. In 2009 and 2010, two disease epizootics involving wild stingrays occurred at Sea World marine aquarium. Necropsy, histopathology, bacteriology and PCR determined that the cause of deaths of 12 giant Queensland grouper, three wild fish, six estuary rays, Dasyatis fluviorum (Ogilby), one mangrove whipray, Himantura granulata (Macleay), and one eastern shovelnose ray, Aptychotrema rostrata (Shaw), was Streptococcus agalactiae septicaemia. Biochemical testing of 34 S. agalactiae isolates from giant Queensland grouper, wild fish and stingrays showed all had identical biochemical profiles. The 16S rRNA gene sequences of isolates confirmed all isolates were S. agalactiae; genotyping of selected S. agalactiae isolates showed the isolates from giant Queensland grouper were serotype Ib, whereas isolates from wild fish and stingrays closely resembled serotype II. This is the first report of S. agalactiae from wild giant Queensland grouper and other wild tropical fish and stingray species in Queensland, Australia. © 2012 Blackwell Publishing Ltd and State of Queensland.

Modeling of optical fields in laser microcavities using a modal method

DEFF Research Database (Denmark)

Gregersen, Niels

2013-01-01

mechanism limiting the Q factor is the poor modal overlap between the cavity Bloch mode and the mirror Bloch mode. Also, the strong connement will generally lead to highly divergent far field patterns and thus low collection efficiency. In this scenario, Bloch-wave engineering [1] and the introduction...... of adiabatic transitions emerge as powerful design tools to control the optical mode. In the modal method, the eld is expanded on the eigenmodes of z-invariant layers and on the Bloch modes of periodic sections. Using mode matching at the interfaces, the method gives direct access to re ection and transmission...

Estimation of Tissue Distribution of mRNA Transcripts for Desaturase and Elongase Enzymes in Channa striata (Bloch, 1793 Fingerlings using PCR Technique

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M. Aliyu-Paiko

2013-06-01

Full Text Available Fish species are varied in their capacity to biosynthesize n-3 highlyunsaturated fatty acids (HUFA such as eicosapentaenoic and docosahexaenoic acids (EPA & DHA that are crucial to the health and well-being of all higher vertebrates. Experts report that HUFA metabolism involves enzyme-mediated fatty acyl desaturation (FAD and elongation (FAE processes. In previous studies, different workers cloned, characterized, identified and reported several genes for FAD and FAE enzymes in different fish species such as Atlantic salmon, gilthead seabream, rainbow trout and zebrafish, and also demonstrated the up- and down-regulation in the activity of these enzymes in response to fluctuations in dietary HUFA. In this paper, we report on the expression of genes (mRNA transcripts for FAD and FAE enzymes in different tissues of Channa striata (Bloch, 1793 fingerling, to evaluate the tissues of the fish in which activity of both enzymes are high. To achieve this objective, we used conventional polymerase chain reaction (PCR technique to isolate and quantify the absolute copy number for each gene transcripts from 8 different tissues of the fish (reared with a commercial feed. Our estimate show that the distribution of the 2 enzyme transcripts were significantly (P < 0.05 higher in the liver and brain of C. striata than detected in the 6 other tissues evaluated (muscle, ovary, testis, intestine, kidney and skin. Subsequently, we discuss here extensively, the implication of this observation with respect to the use of vegetable oils (VO as substitute to fish oil (FO in diets for freshwater fish species.

Multidimensional periodic Schrödinger operator perturbation theory and applications

CERN Document Server

Veliev, Oktay

2015-01-01

The book describes the direct problems and the inverse problem of the multidimensional Schrödinger operator with a periodic potential. This concerns perturbation theory and constructive determination of the spectral invariants and finding the periodic potential from the given Bloch eigenvalues. The unique method of this book derives the asymptotic formulas for Bloch eigenvalues and Bloch functions for arbitrary dimension. Moreover, the measure of the iso-energetic surfaces in the high energy region is construct and estimated. It implies the validity of the Bethe-Sommerfeld conjecture for arbitrary dimensions and arbitrary lattices. Using the perturbation theory constructed in this book, the spectral invariants of the multidimensional operator from the given Bloch eigenvalues are determined. Some of these invariants are explicitly expressed by the Fourier coefficients of the potential. This way the possibility to determine the potential constructively by using Bloch eigenvalues as input data is given. In the ...

Sound waves and dynamics of superfluid Fermi gases in optical lattices

International Nuclear Information System (INIS)

Zhang Aixia; Xue Jukui

2009-01-01

The sound waves, the stability of Bloch waves, the Bloch oscillation, and the self-trapping phenomenon in interacting two-component Fermi gases throughout the BEC-BCS crossover in one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) optical lattices are discussed in detail. Within the hydrodynamical theory and by using the perturbative and tight-binding approximation, sound speed in both weak and tight 1D, 2D, 3D optical lattices, and the criteria for occurrences of instability of Bloch waves and self-trapping of Fermi gases along the whole BEC-BCS crossover in tight 1D, 2D, 3D optical lattices are obtained analytically. The results show that the sound speed, the criteria for occurrences of instability of Bloch waves and self-trapping, and the destruction of Bloch oscillation are modified dramatically by the lattice parameters (lattice dimension and lattice strength), the atom density or atom number, and the atom interaction.

Magnetic resonance described in the excitation dependent rotating frame of reference.

Science.gov (United States)

Tahayori, Bahman; Johnston, Leigh A; Mareels, Iven M Y; Farrell, Peter M

2008-01-01

An excitation dependent rotating frame of reference to observe the magnetic resonance phenomenon is introduced in this paper that, to the best of our knowledge, has not been used previously in the nuclear magnetic resonance context. The mathematical framework for this new rotating frame of reference is presented based on time scaling the Bloch equation after transformation to the classical rotating frame of reference whose transverse plane is rotating at the Larmor frequency. To this end, the Bloch equation is rewritten in terms of a magnetisation vector observed from the excitation dependent rotating frame of reference. The resultant Bloch equation is referred to as the time scaled Bloch equation. In the excitation dependent rotating frame of reference whose coordinates are rotating at the instantaneous Rabi frequency the observed magnetisation vector is a much slower signal than the true magnetisation in the rotating frame of reference. As a result the ordinary differential equation solvers have the ability to solve the time scaled version of the Bloch equation with a larger step size resulting in a smaller number of samples for solving the equation to a desired level of accuracy. The simulation results for different types of excitation are presented in this paper. This method may be used in true Bloch simulators in order to reduce the simulation time or increase the accuracy of the numerical solution. Moreover, the time scaled Bloch equation may be employed to determine the optimal excitation pattern in magnetic resonance imaging as well as designing pulses with better slice selectivity which is an active area of research in this field.

ESTIMASI KELIMPAHAN IKAN GABUS (Channa striata Bloch, 1793 DENGAN METODE HIDROAKUSTIK DI SUNGAI LEMPUING, SUMATERA SELATAN

Directory of Open Access Journals (Sweden)

Zulkarnaen Fahmi

2016-03-01

Full Text Available Kegiatan pengkajian stok sumberdaya ikan yang dilakukan secara berkala bertujuan untuk optimasi pemanfaatan sumberdaya perikanan bagi kegiatan perikanan tangkap. Kegiatan pengkajian stok ikandengan survey akustik di perairan Lubuk Lampam telah dilakukan pada tahun 2011 sebanyak 2 (dua kali dengan interval waktu 3 (tiga bulan untuk melihat perubahan kelimpahan ikan gabus (Channa striatadi perairan tersebut. Ekstraksi data akustik meliputi data sebaran kelimpahan dan distribusi ukuran ikan dilakukan untuk melihat keragaman (variance nilai yang diperoleh. Hasil penelitian menunjukkan bahwa estimasi rata-rata kelimpahan ikan pada bulan Maret sebesar 7.53 ± 1.33 ekor/m2  lebih rendah dibandingkan pada bulan Mei sebesar 53.11 ± 9.43  ekor/m2  . Biomass ikan pada bulan Maret sebesar 75.59 ± 30.22 kg/ha lebih rendah dibandingkan pada bulan Mei sebesar 521 ± 65.01 kg/ha. Nilai rataan target strength ikan tunggal yang terdeteksi pada bulan Maret sebesar -54.81 ± 0.9 dB lebih rendah dibandingkan pada bulan Mei sebesar -50.03 ± 0.35 dB. Estimasi kelimpahan dan distribusi ikan di sungai Lempuing menunjukkan nilai keragaman (variance yang lebih rendah pada bulan Maret dibandingkan dengan bulan Mei 2011 untuk parameter kelimpahan dan biomass ikan, sedangkan untuk nilai rataan target strength ikan menunjukkan sebaliknya. Fish assessment using hydroacoustic in inland water was conducted to optimize fish exploitation activity. Successive hydroacoustic survey was conducted twice with interval three months in 2011 to estimated distribution fish abundance and size distribution of snakehead fish (Channa striata Bloch, 1793 in Lempuing River, South Sumatera. Reability test was conducted on hydroacoustic data including data distribution and abundance of fish size distribution to obtain edvariance value. The results showed that the average estimate abundance of fish on March about 7.53 ± 1.33 fish/m2 lower than in the month of May at 53.11 ± 9.43 fish/m2

Eğirdir Gölü'nde Gümüşi Havuz Balığı, Carassius gibelio (Bloch, 1782 Avcılığında Kullanılan Monofilament Fanyalı Ağların Seçiciliği

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Bayram KORKMAZ

2014-09-01

Full Text Available In this study, it has been investigated that the characteristics of the selectivity of monofilament trammel nets having 50, 55, 60 mm bar length. This study was carried out on prussian carp Carassius gibelio (Bloch,1782 caught in Lake Eğirdir. An indirect method developed by Holt (1963 was used for determining the selectivity parameters. Common selection factor as SF=4.753 and common standard deviation as SD=2.347 were calculated for monofilament trammel nets. Common selection factor used of the optimum catch lengths of prussian carp in 50, 55 and 60 mm bar length were 23.77; 26.14 and 28.52 cm respectively. The optimum catch lengths were compared with lenghts at first maturity of prussian carp in Lake Eğirdir. Trammel nets of this study do not cause the overfishing on the prussian carp stock

Hybrid Bloch brane

Energy Technology Data Exchange (ETDEWEB)

Bazeia, D.; Lima, Elisama E.M.; Losano, L. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil)

2017-02-15

This work reports on models described by two real scalar fields coupled with gravity in the five-dimensional spacetime, with a warped geometry involving one infinite extra dimension. Through a mechanism that smoothly changes a thick brane into a hybrid brane, one investigates the appearance of hybrid branes hosting internal structure, characterized by the splitting on the energy density and the volcano potential, induced by the parameter which controls interactions between the two scalar fields. In particular, we investigate distinct symmetric and asymmetric hybrid brane scenarios. (orig.)

Roland Weber first part

DEFF Research Database (Denmark)

2016-01-01

The Sooty bloch complex - species identity, infection biology and control options. Rubbery rot and Black summer rot - two new diseases of apple......The Sooty bloch complex - species identity, infection biology and control options. Rubbery rot and Black summer rot - two new diseases of apple...

Almost periodic Hamiltonians: an algebraic approach

International Nuclear Information System (INIS)

Bellissard, J.

1981-07-01

We develop, by analogy with the study of periodic potential, an algebraic theory for almost periodic hamiltonians, leading to a generalized Bloch theorem. This gives rise to results concerning the spectral measures of these operators in terms of those of the corresponding Bloch hamiltonians

Coherent excitation of vibrational levels using ultra short pulses

CSIR Research Space (South Africa)

De Clercq, LE

2009-07-01

Full Text Available population in a specific vibrational level. We used two approaches to do this, in the one model we used Von Neumann’s equations and the other the Optical Bloch equations (OBE’s). In this poster presentation the Optical Bloch model was used to do...

23 octobre 2012 - Le Président du Conseil général de la Haute-Savoie C. Monteil signe le livre d'or en présence du Directeur général R. Heuer, la chef des Relations Internationales F. Pauss, le chef du département Physique P. Bloch et le chef du département Technologie F. Bordry; visite du hall de test des aimants supraconducteurs du LHC avec F. Bordry.

CERN Multimedia

Maximilien Brice

2012-01-01

23 octobre 2012 - Le Président du Conseil général de la Haute-Savoie C. Monteil signe le livre d'or en présence du Directeur général R. Heuer, la chef des Relations Internationales F. Pauss, le chef du département Physique P. Bloch et le chef du département Technologie F. Bordry; visite du hall de test des aimants supraconducteurs du LHC avec F. Bordry.

Dr. Yu Wang, Director, Natural Science Division, National Science Council, Taiwan

CERN Document Server

Patrice Loïez

2001-01-01

Photo 01: L. to r.: Dr. Philippe Bloch, CERN CMS ECAL Deputy Project Manager, Dr. Yu Wang, Dr. Etiennette Auffray, CERN, responsible of the CERN ECAL Regional Centre. Photo 02: L. to r.: Dr. Yu Wang, Dr. Philippe Bloch, Dr. Apollo GO, National Central University, Taiwan, Dr. Etiennette Auffray.

Separable decompositions of bipartite mixed states

Science.gov (United States)

Li, Jun-Li; Qiao, Cong-Feng

2018-04-01

We present a practical scheme for the decomposition of a bipartite mixed state into a sum of direct products of local density matrices, using the technique developed in Li and Qiao (Sci. Rep. 8:1442, 2018). In the scheme, the correlation matrix which characterizes the bipartite entanglement is first decomposed into two matrices composed of the Bloch vectors of local states. Then, we show that the symmetries of Bloch vectors are consistent with that of the correlation matrix, and the magnitudes of the local Bloch vectors are lower bounded by the correlation matrix. Concrete examples for the separable decompositions of bipartite mixed states are presented for illustration.

Extended rate equations

International Nuclear Information System (INIS)

Shore, B.W.

1981-01-01

The equations of motion are discussed which describe time dependent population flows in an N-level system, reviewing the relationship between incoherent (rate) equations, coherent (Schrodinger) equations, and more general partially coherent (Bloch) equations. Approximations are discussed which replace the elaborate Bloch equations by simpler rate equations whose coefficients incorporate long-time consequences of coherence

Introduction to spintronics

CERN Document Server

Bandyopadhyay, Supriyo

2008-01-01

The Early History of Spin Spin The Bohr Planetary Model and Space Quantization The Birth of "Spin" The Stern-Gerlach Experiment The Advent of Spintronics The Quantum Mechanics of Spin Pauli Spin Matrices The Pauli Equation and Spinors More on the Pauli Equation Extending the Pauli Equation - the Dirac Equation The Time Independent Dirac Equation Appendix The Bloch Sphere The Spinor and the "Qubit" The Bloch Sphere Concept Evolution of a Spinor Spin-1/2 Particle in a Constant Magnetic Field: Larmor Precession Preparing to Derive the Rabi Formula The Rabi Formula The Density Matrix The Density Matrix Concept: Case of a Pure State Properties of the Density Matrix Pure Versus Mixed State Concept of the Bloch Ball Time Evolution of the Density Matrix: Case of Mixed State The Relaxation Times T1 and T2 and the Bloch Equations Spin Orbit Interaction Spin Orbit Interaction in a Solid Magneto-Electric Sub-Bands in Quantum Confined Structures in the Presence of Spin-Orbit Interaction Dispersion Relations of Spin Resolv...

Klimti tööd tagasi saanud juudi pere müüb need maha

Index Scriptorium Estoniae

2006-01-01

Klimti maalide "Kasemets/Pöögimets" (1901), "Adele Bloch-Bauer II" (1912), "Õunapuu" (1912) ja "Majad Unterachis Attersee ääres" (1916) õiguspäraseks omanikuks tunnistati Ferdinand Bloch-Baueri vennatütar Maria Altmann. Maalid müüakse sügisel. Praegu asuvad maalid New Yorgis saksa ja austria kunsti muuseumis Neue Galerie's

Cambios alimenticios en tres especies de Sphoeroides (Tetraodontiformes: Tetraodontidae posterior al huracán Isidoro en Bocana de la Carbonera, Sureste del Golfo de México

Directory of Open Access Journals (Sweden)

Sonia Eugenia Palacios-Sánchez

2010-12-01

Full Text Available Se analizan los cambios producidos por el huracán Isidoro en la repartición de los recursos alimenticios de tres especies de peces de la familia Tetraodontidae (Sphoeroides nephelus, S. spengleri y S testudineus que cohabitan en la Bocana de la Carbonera (sureste del Golfo de México. Los Sphoeroides spp. basaron su alimentación en los organismos bentónicos, sobresaliendo por su consumo el mejillón (Brachidontes sp., la lapa (Balanus sp. y gasterópodos (Crepidula sp.. Previo al impacto del huracán, las tres especies utilizaron de forma diferencial los recursos alimenticios disponibles (bivalvos, gasterópodos, cirrípedos y decápodos recurriendo a diferentes estrategias que les permitieron minimizar la competencia interespecífica y coexistir. Posterior al impacto, la disponibilidad de las presas disminuyó y la competencia interespecífica por el alimento se incrementó provocando que S. testudineus y S. nephelus cambiaran su espectro trófico (xiphosuros, anfípodos, isópodos y detritus desplazando a S. spengleri de la bocana. La repartición de los recursos alimenticios estuvo condicionada por la abundancia y diversidad de las presas así como la respuesta adaptativa de cada especie.Feeding changes for three Sphoeroides species (Tetraodontiformes: Tetraodontidae after Isidore hurricane impact in Carbonera Inlet, Southeastern Gulf of Mexico. The coexistence of ecologically similar species may occur because of resources distribution, such as prey and habitat type and segregation time, that minimizes the interspecific competition. The changes brought about by Hurricane Isidore in the distribution of food resources by three coexisting fish species of the family Tetraodontidae (Sphoeroides nephelus, S. spengleri and S testudineus, were analyzed at the Carbonera Inlet. Sphoeroides spp. based their food on benthic organisms; principally, they consume mussels (Brachidontes sp., barnacles (Balanus sp. and gastropods (Crepidula sp. Before

BIOLOGICAL CHARACTERISTICS OF PRUSSIAN CARP (CARASSIUS AURATUS GIBELIO (BLOCH, 1782 COMMERCIAL STOCK OF THE DNIEPER-BUG ESTUARY

Directory of Open Access Journals (Sweden)

К. Heina

2017-09-01

Full Text Available Purpose. To provide the biological assessment of the silver Prussian carp (Carassius auratus gibelio (Bloch, 1782 commercial stock of the Dnieper-Bug estuary in the conditions of the transformed Dnieper river flow. Methodology. During the analysis of the biological state of the Prussian carp commercial stock, the main attention was given to the dynamics of age and sexual structure, length-weight growth rate, absolute fecundity and condition factor. The basic data were collected during the work of control-observation stations of the Institute of Fisheries in the Dnieper-Bug estuary during the current century. The collection and processing of ichthyological materials were performed in accordance with the generally accepted methodologies. Findings. The analysis showed that during the current century, the age structure of the Prussian carp of the Dnieper-Bug estuary was the most labile among other commercial cyprinids. It was found that as a result of an increase in the right wing of the age series, there was a gradual increase of the mean weighted age of its commercial stock. At the beginning of studies (2001-2002, the core of the stock was formed by age-3-6 fish (up ; however in subsequent years, a displacement of dominant groups toward the dominance of age-4-7 fish (more than 80% of the total stock was observed. At the same time, the relative number of age-3 fish (recruits was at a relatively high level – up to 10.6%. The linear growth varied more intensively until the age-5, but it reduced with ageing and did not show high variability. The body weight most variable was in age-4 fish (Cv=9.62%. The noted insignificant deviations in the body weight growth rate of the right wing of the age series was due to stable predominance of females in the stock structure, which were characterized by a variability of the mean weight as a result of different development of gonads. The dynamics of the age-related changes in the condition factor indicated on a

A Comparison of Implications in Orthomodular Quantum Logic—Morphological Analysis of Quantum Logic

Directory of Open Access Journals (Sweden)

Mitsuhiko Fujio

2012-01-01

Full Text Available Morphological operators are generalized to lattices as adjunction pairs (Serra, 1984; Ronse, 1990; Heijmans and Ronse, 1990; Heijmans, 1994. In particular, morphology for set lattices is applied to analyze logics through Kripke semantics (Bloch, 2002; Fujio and Bloch, 2004; Fujio, 2006. For example, a pair of morphological operators as an adjunction gives rise to a temporalization of normal modal logic (Fujio and Bloch, 2004; Fujio, 2006. Also, constructions of models for intuitionistic logic or linear logics can be described in terms of morphological interior and/or closure operators (Fujio and Bloch, 2004. This shows that morphological analysis can be applied to various non-classical logics. On the other hand, quantum logics are algebraically formalized as orhomodular or modular ortho-complemented lattices (Birkhoff and von Neumann, 1936; Maeda, 1980; Chiara and Giuntini, 2002, and shown to allow Kripke semantics (Chiara and Giuntini, 2002. This suggests the possibility of morphological analysis for quantum logics. In this article, to show an efficiency of morphological analysis for quantum logic, we consider the implication problem in quantum logics (Chiara and Giuntini, 2002. We will give a comparison of the 5 polynomial implication connectives available in quantum logics.

Dilation of non-quasifree dissipative evolution

Energy Technology Data Exchange (ETDEWEB)

Varilly, J C [Costa Rica Univ., San Jose. Escuela de Matematica

1981-03-01

A semigroup evolution for the 1/2-spin which admits a conservative dilation is known to be governed by a Bloch equation in a standard form. Here we construct a conservative dilation directly from the Bloch equation, thus yielding an example of a dilation scheme for an evolution which is not quasifree. Moreover, we show that this conservative evolution is never ergodic in the non-quasifree case.

The multiplication operators on some analytic function spaces of the ...

Indian Academy of Sciences (India)

Given f ∈ E1(Bn) we still denote by f (ξ) (ξ ∈ Sn) its admissible limit at the boundary which exists a.e. A ... BMOA is a Banach space under the following norm: || f ||2 ..... The same inequalities hold when ga is replaced by fa by the same observations. ... The case of the Bloch space and the weighted Bloch space. As in the ...

Matter-wave dark solitons in optical lattices

International Nuclear Information System (INIS)

Louis, Pearl J Y; Ostrovskaya, Elena A; Kivshar, Yuri S

2004-01-01

We analyse the Floquet-Bloch spectrum of matter waves in Bose-Einstein condensates loaded into single-periodic optical lattices and double-periodic superlattices. In the framework of the Gross-Pitaevskii equation, we describe the structure and analyse the mobility properties of matter-wave dark solitons residing on backgrounds of extended nonlinear Bloch-type states. We demonstrate that interactions between dark solitons can be effectively controlled in optical superlattices

A new species of Probursata Bravo-Hollis, 1984 (Mogenea: Heteraxinidae: Heteraxininae) parasite of Oligoplites spp. (Osteichthyes: Carangidae) from the coast of the state of Rio de Janeiro, Brazil

OpenAIRE

Ricardo M. Takemoto; J. F. R. Amato; José Luis Luque

1993-01-01

Probursata brasiliensis n. sp., a gill filament parasite of carangid fishes, O. palometa (Cuvier), Oligoplites saurus (Bloch & Schneider), and O. saliens (Bloch), from the Brazilian coast, is described and illustrated. The new species differs from Probursata veraecrucis Bravo-Hollis, 1984, the type and only species of this genus by the presence of spines in the auricular expansions of the genital atrium, by the trifurcate supplementary process of the clamp's midsclerite, and by having a l...

Copépodes parasitos de Oligoplites spp. (Osteichthyes, Carangidae) da costa brasileira, com a redescrição de Tuxophorus caligodes Wilson, 1908 (Siphonostomatoida, Tuxophoridae)

OpenAIRE

Takemoto, Ricardo Massato; Universidade Estadual de Matingá; Luque, José Luis; UFRRJ; Luque, José Luis; UFRRJ

2008-01-01

Four species of caligid copepods, parasites of Oligoplites palometa (Cuvier, 1833), O. saurus (Bloch & Schneider, 1801) and O. saliens (Bloch, 1793) (Osteichthyes: Carangidae) from the Sepetiba Bay, coast of the state of Rio de Janeiro, Brazil, are presented. New geographical and host records for Caligus robustus Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905, C. bonito Wilson, 1905 and Metacaligus rufus (Wilson, 1908) are given. Caligus oligoplitisi Carvalho, 1954 is considered a new jun...

Monogeneans of leatherjackets, Oligoplites spp. (Osteichthyes: Carangidae), with the description of a new species of Metacamopia (Monogenea: Allodiscocotylidae) from the coast of the State of Rio de Janeiro, Brazil

OpenAIRE

Takemoto,Ricardo M; Amato,JFR; Luque,José Luis

1996-01-01

Metacamopia oligoplites n. sp., a gill filament parasite of carangid fishes of three species of Oligoplites Gill, O. palometa (Cuvier), O. saurus (Bloch & Schneider), and O. saliens (Bloch), from the coast of the State of Rio de Janeiro, Brazil, is described and illustrated. Metacamopia oligoplites n. sp. differs from M. indica by: the shape of the body; the pre-, para-, and post-germarial testes; vaginas lacking sclerotized structures; well-developed seminal receptacles; muscular sleeves...

H.E. Mr Leonid A. Skotnikov, Ambassador, Permanent Representative of the Russian Federation to the United Nations and other International Organisations in Geneva

CERN Multimedia

Maximilien Brice

2003-01-01

Photo 01: H.E. Mr Leonid A. Skotnikov, Ambassador of the Russian Federation to the United Nations and other International Organisations in Geneva (centre) with (from left to right) V. Kaftanov, Ph. Bloch, N. Koulberg, F. Grishaev Photo 02: H.E. Mr Leonid A. Skotnikov, Ambassador of the Russian Federation to the United Nations and other International Organisations in Geneva (centre) with Ph. Bloch (behind the Ambassador, V. Kaftanov) visiting the crystal laboratory in building 27.

Manipulating quantum information on the controllable systems or subspaces

OpenAIRE

Zhang, Ming; Xi, Zairong; Wei, Jia-Hua

2010-01-01

In this paper, we explore how to constructively manipulate qubits by rotating Bloch spheres. It is revealed that three-rotation and one-rotation Hamiltonian controls can be constructed to steer qubits when two tunable Hamiltonian controls are available. It is demonstrated in this research that local-wave function controls such as Bang-Bang, triangle-function and quadratic function controls can be utilized to manipulate quantum states on the Bloch sphere. A new kind of time-energy performance ...

Myocardial T1 mapping at 3.0 tesla using an inversion recovery spoiled gradient echo readout and bloch equation simulation with slice profile correction (BLESSPC) T1 estimation algorithm.

Science.gov (United States)

Shao, Jiaxin; Rapacchi, Stanislas; Nguyen, Kim-Lien; Hu, Peng

2016-02-01

To develop an accurate and precise myocardial T1 mapping technique using an inversion recovery spoiled gradient echo readout at 3.0 Tesla (T). The modified Look-Locker inversion-recovery (MOLLI) sequence was modified to use fast low angle shot (FLASH) readout, incorporating a BLESSPC (Bloch Equation Simulation with Slice Profile Correction) T1 estimation algorithm, for accurate myocardial T1 mapping. The FLASH-MOLLI with BLESSPC fitting was compared with different approaches and sequences with regards to T1 estimation accuracy, precision and image artifact based on simulation, phantom studies, and in vivo studies of 10 healthy volunteers and three patients at 3.0 Tesla. The FLASH-MOLLI with BLESSPC fitting yields accurate T1 estimation (average error = -5.4 ± 15.1 ms, percentage error = -0.5% ± 1.2%) for T1 from 236-1852 ms and heart rate from 40-100 bpm in phantom studies. The FLASH-MOLLI sequence prevented off-resonance artifacts in all 10 healthy volunteers at 3.0T. In vivo, there was no significant difference between FLASH-MOLLI-derived myocardial T1 values and "ShMOLLI+IE" derived values (1458.9 ± 20.9 ms versus 1464.1 ± 6.8 ms, P = 0.50); However, the average precision by FLASH-MOLLI was significantly better than that generated by "ShMOLLI+IE" (1.84 ± 0.36% variance versus 3.57 ± 0.94%, P < 0.001). The FLASH-MOLLI with BLESSPC fitting yields accurate and precise T1 estimation, and eliminates banding artifacts associated with bSSFP at 3.0T. © 2015 Wiley Periodicals, Inc.

Proposal for a source of polarized protons; Projet de source de protons polarises

Energy Technology Data Exchange (ETDEWEB)

Abragam, A.; Winter, J. M. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Centre d' Etudes Nucleaires de Saclay, BP2, Gif-sur-Yvette (France)

1959-07-01

Proposal for a source of polarized protons based on the theory of adiabatic fast passage due to F. Bloch. Reprint of a paper published in 'Physical review letters', vol 1, n. 10, 15 Nov 1958, p. 374-375 [French] On propose une methode nouvelle pour la realisation d'une source de protons polarises basee sur la theorie du passage adiabatique de F. Bloch. Reproduction d'un article publie dans 'Physical review letters', vol 1, n. 10, 15 nov 1958, p. 374-375.

The Laughter as Hope Principle

Directory of Open Access Journals (Sweden)

Mateus Domingues da Silva

2015-04-01

Full Text Available The work aims to establish a parallel between the concept of laughter and the Hope Principle of Ernst Bloch, differentiating their relationship between the pursuit of individual happiness, said to be ideological, deceptive and precarious, and the pursuit of collective happiness, altruistic, that despite utopian it is also true and real, just for being selfless and real because, as a collective expression, indicating concretely and politically, is a real possibility.Keywords: Laughter, Hope Principle, Ernest Bloch, altruism.

Energy spectrum, the spin polarization, and the optical selection rules of the Kronig-Penney superlattice model with spin-orbit coupling

Science.gov (United States)

Li, Rui

2018-02-01

The Kronig-Penney model, an exactly solvable one-dimensional model of crystal in solid physics, shows how the allowed and forbidden bands are formed in solids. In this paper, we study this model in the presence of both strong spin-orbit coupling and the Zeeman field. We analytically obtain four transcendental equations that represent an implicit relation between the energy and the Bloch wave vector. Solving these four transcendental equations, we obtain the spin-orbital bands exactly. In addition to the usual band gap opened at the boundary of the Brillouin zone, a much larger spin-orbital band gap is also opened at some special sites inside the Brillouin zone. The x component of the spin-polarization vector is an even function of the Bloch wave vector, while the z component of the spin-polarization vector is an odd function of the Bloch wave vector. At the band edges, the optical transition rates between adjacent bands are nonzero.

Light quantum particles in a metallic environment

International Nuclear Information System (INIS)

Hedegad, P.

1986-04-01

The basic mechanism that limits the quantum behavior of light particles are fluctuations in the environment. We here develop a path integral formalism that accounts for the influence of the environment on the quantum motion of such particles. As our prime example we discuss a particle that moves in a tight binding band and interacts with an electron gas environment. This situation has received experimental attention recently in the case of muon diffusion in metals, and in the theoretical discussion of hydrogen on metal surfaces. It is shown that the adiabatic approximation, usually applied to such problems, does not apply. This has basically two consequences. At low temperatures we find that the particle moves in Bloch states with a renormalized (more narrow) band width. For higher temperatures (k B T > W ren ) the Bloch states acquire a lifetime that is shorter than K/W ren , which means a complete breakdown of the Bloch picture. (orig.)

Review of the Indo-Pacific labrid fish genus Hemigymnus

OpenAIRE

Randall, John E.

2013-01-01

The labrid fish genus Hemigymnus Günther consists of three relatively large coral-reef species: the wide-ranging Indo-Pacific H. fasciatus (Bloch) and H. melapterus (Bloch), and H. sexfasciatus (Rüppell) of the Red Sea and Gulf of Aden, usually regarded as a synonym of H. fasciatus. It is treated here as a species, distinguished by color pattern, longer pelvic fins of the terminal male, and fewer gill rakers. These three fishes are generally found as solitary individuals over sand or sand-and...

Engineering topological edge states in two dimensional magnetic photonic crystal

Science.gov (United States)

Yang, Bing; Wu, Tong; Zhang, Xiangdong

2017-01-01

Based on a perturbative approach, we propose a simple and efficient method to engineer the topological edge states in two dimensional magnetic photonic crystals. The topological edge states in the microstructures can be constructed and varied by altering the parameters of the microstructure according to the field-energy distributions of the Bloch states at the related Bloch wave vectors. The validity of the proposed method has been demonstrated by exact numerical calculations through three concrete examples. Our method makes the topological edge states "designable."

Cytogenetic characterization of Hoplias malabaricus (Bloch, 1794 from the Ctalamochita River (Córdoba, Argentina: first evidence for southernmost populations of this species complex and comments on its biogeography

Directory of Open Access Journals (Sweden)

Diego Javier Grassi

2017-01-01

Full Text Available Hoplias malabaricus (Bloch, 1794, a predatory freshwater fish with a wide distribution throughout South America, represents a species complex with seven well characterized karyomorphs at the cytogenetic level. Although this species has been extensively studied in several Brazilian basins, data are still scarce for hydrographic systems from other South American countries. This study aims to characterize cytogenetically the Hoplias malabaricus populations from the Argentinean Central Region, close to the southernmost distribution of this species complex. A total of 32 specimens from the Ctalamochita River, a tributary of Lower Paraná Basin located in the province of Córdoba, were analyzed using cytogenetic techniques (Giemsa staining, C- and Ag-NOR banding and fluorescent in situ hybridization with 18S rDNA. All the specimens showed diploid number 2n=42, chromosomic formula 22m + 20sm and absence of sexual chromosomes. Thus, the analyzed populations belong to the karyomorph named A. These populations showed a remarkable degree of divergence in their cytogenetic traits such as karyotypic formula, C-banding, NORs and 18S rDNA patterns for Hoplias malabaricus from other populations bearing the same karyomorph in the Middle and Upper Paraná Basin. These findings are consistent with molecular data from a recent study (where specimens collected in the present work were included, which indicate a closer phylogenetic relationship of Hoplias malabaricus populations from the Ctalamochita River with those from the Uruguay basin and the coastal regions of South Brazil than with populations from the Middle and Upper Paraná Basin. Overall, these pieces of evidence highlight the distinctive features of Hoplias malabaricus from the Ctalamochita River, and also reveal a complex history of dispersion of these populations. The present work is the first to provide cytogenetic information and include some phylogeographic aspects of Hoplias malabaricus populations

Comparison of spatial harmonics in infinite and finite Bragg stacks for metamaterial homogenization

DEFF Research Database (Denmark)

Clausen, Niels Christian Jerichau; Arslanagic, Samel; Breinbjerg, Olav

2014-01-01

Metamaterial homogenization may be based on the dominance of a single Floquet-Bloch spatial harmonic in an infinite periodic structure - with the dominance quantified in terms of the relative magnitude of the associated spatial harmonic Poynting vector. For the corresponding finite structure...... the field is not quasi-periodic and cannot be expanded in Floquet-Bloch spatial harmonics; however, a set of pseudo spatial harmonics can be defined and the dominance of a single such harmonic likewise be used to determine whether the structure can be homogenized. For three different lossless Bragg stack...

Parasitic copepods on Oligoplites spp. (Osteichthyes, Carangidae from the Brazilian coastal zone, with the redescription of Tuxophorus caligodes Wilson, 1908 (Siphonostomatoida, Tuxophoridae Copépodes parasitos de Oligoplites spp. (Osteichthyes, Carangidae da costa brasileira, com a redescrição de Tuxophorus caligodes Wilson, 1908 (Siphonostomatoida, Tuxophoridae

Directory of Open Access Journals (Sweden)

Ricardo Massato Takemoto

2002-05-01

Full Text Available Four species of caligid copepods, parasites of Oligoplites palometa (Cuvier, 1833, O. saurus (Bloch & Schneider, 1801 and O. saliens (Bloch, 1793 (Osteichthyes: Carangidae from the Sepetiba Bay, coast of the state of Rio de Janeiro, Brazil, are presented. New geographical and host records for Caligus robustus Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905, C. bonito Wilson, 1905 and Metacaligus rufus (Wilson, 1908 are given. Caligus oligoplitisi Carvalho, 1954 is considered a new junior synonym of C. robustus. Fishes of the genus Oligoplites are new host records for this species of copepod. Redescription and illustration of Tuxophorus caligodes Wilson, 1908, collected on the body surface of Oligoplites saliens, O. palometa and O. saurus, are provided.Quatro espécies de copépodes caligídeos, parasitos de Oligoplites palometa (Cuvier, 1833, O. saurus (Bloch & Schneider, 1801 e O. saliens (Bloch, 1793 (Osteichthyes, Carangidae da Baia de Sepetiba, litoral do Estado do Rio de Janeiro, Brasil, são descritos. São apresentados o registro de novo hospedeiro e nova distribuição geográfica para Caligus robustus Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905, C. bonito Wilson, 1905 e Metacaligus rufus (Wilson, 1908. Caligus oligoplitisi Carvalho, 1954, é considerado novo sinônimo júnior de C. robustus. Tuxophorus caligodes Wilson, 1908, coletado na superfície do corpo de Oligoplites saliens, O. palometa e O. saurus é redescrito e ilustrado. Peixes do gênero Oligoplites são novos hospedeiros para estas espécies de copépodes.

Quantum qubit measurement by a quantum point contact with a quantum Langevin equation approach

International Nuclear Information System (INIS)

Dong, Bing; Lei, X.L.; Horing, N.J.M.; Cui, H.L.

2007-01-01

We employ a microscopic quantum Heisenberg-Langevin equation approach to establish a set of quantum Bloch equations for a two-level system (coupled quantum dots) capacitively coupled to a quantum point contact (QPC). The resulting Bloch equations facilitate our analysis of qubit relaxation and decoherence in coupled quantum dots induced by measurement processes at arbitrary bias-voltage and temperature. We also examine the noise spectrum of the meter output current for a symmetric qubit. These results help resolve a recent debate about a quantum oscillation peak in the noise spectrum. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Selection rule for Dirac-like points in two-dimensional dielectric photonic crystals

KAUST Repository

Li, Yan

2013-01-01

We developed a selection rule for Dirac-like points in two-dimensional dielectric photonic crystals. The rule is derived from a perturbation theory and states that a non-zero, mode-coupling integral between the degenerate Bloch states guarantees a Dirac-like point, regardless of the type of the degeneracy. In fact, the selection rule can also be determined from the symmetry of the Bloch states even without computing the integral. Thus, the existence of Dirac-like points can be quickly and conclusively predicted for various photonic crystals independent of wave polarization, lattice structure, and composition. © 2013 Optical Society of America.

A new species of Probursata Bravo-Hollis, 1984 (Mogenea: Heteraxinidae: Heteraxininae parasite of Oligoplites spp. (Osteichthyes: Carangidae from the coast of the state of Rio de Janeiro, Brazil

Directory of Open Access Journals (Sweden)

Ricardo M. Takemoto

1993-06-01

Full Text Available Probursata brasiliensis n. sp., a gill filament parasite of carangid fishes, O. palometa (Cuvier, Oligoplites saurus (Bloch & Schneider, and O. saliens (Bloch, from the Brazilian coast, is described and illustrated. The new species differs from Probursata veraecrucis Bravo-Hollis, 1984, the type and only species of this genus by the presence of spines in the auricular expansions of the genital atrium, by the trifurcate supplementary process of the clamp's midsclerite, and by having a larger number of tests and clamps. This is the first record of the genus Probursata Bravo-Hollis, 1984, in the South Atlantic Ocean.

Entanglement of arbitrary superpositions of modes within two-dimensional orbital angular momentum state spaces

International Nuclear Information System (INIS)

Jack, B.; Leach, J.; Franke-Arnold, S.; Ireland, D. G.; Padgett, M. J.; Yao, A. M.; Barnett, S. M.; Romero, J.

2010-01-01

We use spatial light modulators (SLMs) to measure correlations between arbitrary superpositions of orbital angular momentum (OAM) states generated by spontaneous parametric down-conversion. Our technique allows us to fully access a two-dimensional OAM subspace described by a Bloch sphere, within the higher-dimensional OAM Hilbert space. We quantify the entanglement through violations of a Bell-type inequality for pairs of modal superpositions that lie on equatorial, polar, and arbitrary great circles of the Bloch sphere. Our work shows that SLMs can be used to measure arbitrary spatial states with a fidelity sufficient for appropriate quantum information processing systems.

Influence of ammonia on forming the toxicity of waters from the surface sources of water supply determined on Carassius auratus gibelio (Bloch, 1782

Directory of Open Access Journals (Sweden)

Е. Arystarkhova

2018-03-01

Full Text Available Purpose. Determination of the influence of ammonia in waters from surface sources of water supply of Zhytomyr city on forming the toxicity of these waters determined by test-reactions of atypical motor activity of Carassius auratus gibelio (Bloch, 1782 with the use of the «time sampling» method during 2012–2014. Methodology. Biotesting was performed at the Municipal Enterprise "Zhytomyrvodokanal". Water samples were taken once a month time from the Teteriv river reservoirs and tap water network and then placed into aquaria (8 dm3 on a group. Control and experimental groups of fish were formed according to the following scheme: control group — samples of settled (24 hours tap water; experimental group D-1 — water samples from the Denyshivske reservoir; experimental group D-2 — water samples from the Vidsichne water intake. Test specimens were females of C. auratus gibelio. Biotesting was conducted using the «time sampling» method by keeping fish (n=30 in water for 12 hours. The toxicity indexes of waters were calculated on the basis of the following test-reactions: spiral-like and vector movements, jumping out from water, immobilization and death of fish. Statistical processing of study results were performed using cross-correlation and regression analysis in MS Excel 2007 and Statistica-6. Findings. The study showed an effect of ammonia on the toxicity of waters from reservoirs of the Teteriv river that was determined by atypical motor activity with the use of the «time sampling» method, which consisted in the instantaneous fixation of the number of individuals that favored one or another act of behavior. It was shown that females not adapted to the action of ammonia reacted to its concentration in water of more than 0.55 mg/dm3 by disorders in movements. Unlike fish of experience groups, only single pathological acts were observed in the control group. A positive moderate relationship, which had a tendency to an increase, was

Five new species of philometrid nematodes (Philometridae) from marine fishes off Java, Indonesia.

Science.gov (United States)

Moravec, Frantisek; Walter, Thorsten; Yuniar, Asri Trisnani

2012-06-01

Based on light and scanning electron microscopical studies, the following five species of the Philometridae (Nematoda: Dracunculoidea) are described from female specimens collected from marine fishes off the southwestern coast of Java, Indonesia: Philometra lobotidis sp. n. from the abdominal cavity of the Atlantic tripletail Lobotes surinamensis (Bloch) (Lobotidae, Perciformes); Philometra javaensis sp. n. from the abdominal cavity of the immaculate puffer Arothron immaculatus (Bloch et Schneider) (Tetraodontidae, Tetraodontiformes); Philometra psettoditis sp. n. from the musculature of the Indian spiny turbot Psettodes erumei (Bloch et Schneider) (Psettodidae, Pleuronectiformes); Philometroides indonesiensis sp. n. from the musculature of the hound needlefish Tylosurus crocodilus crocodilus (Péron et Lesueur) (Belonidae, Beloniformes); and Philometroides trichiuri sp. n. from the dorsal fin of the largehead hairtail Trichiurus lepturus Linnaeus (type host) and the savalai hairtail Lepturacanthus savala (Cuvier) (both Trichiuridae, Perciformes). All these new species are distinguished from their congeners parasitizing marine fishes by morphological (mainly the shape and structure of the cephalic and caudal ends and of the oesophagus) and biometrical features. Besides previously known Philometra pellucida (Jägerskiöld, 1893) and Philometra ocularis Moravec, Ogawa, Suzuki, Miyazaki et Donai, 2002, they are the only nominal philometrid species recorded from Indonesian waters.

First record of the Indo-Pacific areolate grouper Epinephelus areolatus (Forsskål, 1775) (Perciformes: Epinephelidae) in the Mediterranean Sea.

Science.gov (United States)

Rothman, Shevy B S; Stern, Nir; Goren, Menachem

2016-01-25

The number of alien species in the Mediterranean Sea is steadily increasing and it seems that the pace has been accelerating since the turn of the century (Galil et al. 2014). In 2015 alone five additional fish species have been reported, Epinephelus geoffroyi (Klunzinger, 1870) (Golani et al. 2015); Stolephorus indicus (van Hasselt, 1823) (Fricke et al. 2015); Sardinella gibbosa (Bleeker, 1849) (Stern et al. 2015); Mobula japanica (Müller & Henle, 1841) (Capapé et al. 2015); and Cryptocentrus caeruleopunctatus (Rüppell, 1830) (Rothman & Goren 2015). Among the ca. 100 alien fish species reported from the Mediterranean to date (Galil & Goren 2014), five Indo-Pacific species belong to the genus Epinephelus Bloch, 1793: Epinephelus coioides (Hamilton, 1822), Epinephelus fasciatus (Forsskål, 1775), Epinephelus malabaricus (Bloch and Schneider, 1804) Epinephelus merra Bloch, 1793 (Golani et al. 2013a) and Epinephelus geoffroyi (Klunzinger, 1870) (Golani et al. 2015). Additional alien Epinephelus species reported from the Mediterranean are excluded for various reasons (Golani et al. 2013b). Here we report the finding of a sixth Indo-Pacific species of this genus along the Mediterranean coast of Israel.

The algebraic geometry of Harper operators

International Nuclear Information System (INIS)

Li, Dan

2011-01-01

Following an approach developed by Gieseker, Knoerrer and Trubowitz for discretized Schroedinger operators, we study the spectral theory of Harper operators in dimensions 2 and 1, as a discretized model of magnetic Laplacians, from the point of view of algebraic geometry. We describe the geometry of an associated family of Bloch varieties and compute their density of states. Finally, we also compute some spectral functions based on the density of states. We discuss the difference between the cases with rational or irrational parameters: for the two-dimensional Harper operator, the compactification of the Bloch variety is an ordinary variety in the rational case and an ind-pro-variety in the irrational case. This gives rise, at the algebro-geometric level of Bloch varieties, to a phenomenon similar to the Hofstadter butterfly in the spectral theory. In dimension 2, the density of states can be expressed in terms of period integrals over Fermi curves, where the resulting elliptic integrals are independent of the parameters. In dimension 1, for the almost Mathieu operator, with a similar argument, we find the usual dependence of the spectral density on the parameter, which gives rise to the well-known Hofstadter butterfly picture. (paper)

Mean excitation energy of polystyrene extracted from proton-stopping-power measurements

International Nuclear Information System (INIS)

Porter, L.E.

1980-01-01

The measured stopping power of polystyrene for 2.2- to 5.9-MeV protons has been analyzed with the Bloch projectile-z 4 correction term and a modified low-velocity projectile-z 3 term included in the Bethe-Bloch formula. When the full-strength Walske K-shell correction was utilized, the mean excitation energy corresponding to the best fit of the measurements was (71.1 +- 1.8) eV. This result was obtained for a value of the free parameter of the low-velocity projectile-z 3 effect formalism of 1.90 +- 0.05, whether or not a Walske L-shell correction was included

Mrs Hitler and her doctor.

Science.gov (United States)

Macleod, Sandy

2005-12-01

The doctor who attended the mother of Adolf Hitler in her terminal illness has been blamed as a cause of the Holocaust. The medical details recorded of this professional relationship are presented and discussed. Dr Bloch's medical care of Mrs Hitler was consistent with the prevailing medical practice of the management of fungating breast carcinoma. Indeed, the general practitioner's care and attention of the family appear to have been astute and supportive. There is nothing to suggest that Dr Bloch's medical care was other than competent. Doctors who have the (mis)fortune to professionally attend major figures of history may be unfairly viewed, despite their appropriate and adequate care.

A new phase coding method using a slice selection gradient for high speed flow velocity meaurements in NMR tomography

International Nuclear Information System (INIS)

Oh, C.H.; Cho, Z.H.; California Univ., Irvine

1986-01-01

A new phase coding method using a selection gradient for high speed NMR flow velocity measurements is introduced and discussed. To establish a phase-velocity relationship of flow under the slice selection gradient and spin-echo RF pulse, the Bloch equation was numerically solved under the assumption that only one directional flow exists, i.e. in the direction of slice selection. Details of the numerical solution of the Bloch equation and techniques related to the numerical computations are also given. Finally, using the numerical calculation, high speed flow velocity measurement was attempted and found to be in good agreement with other complementary controlled measurements. (author)

Symmetry characterization of electrons and lattice excitations

Directory of Open Access Journals (Sweden)

Schober H.

2012-03-01

Full Text Available Symmetry concerns all aspects of a physical system from the electronic orbitals to structural and magnetic excitations. In this article we will try to elaborate the fundamental connection between symmetry and excitations. As excitations are manyfold in physical systems it is impossible to treat them exhaustively. We thus concentrate on the two topics of Bloch electrons and phonons. These two examples are complementary in the sense that Bloch electrons describe single particles in an external periodic potential while phonons exemplify a decoupled system of interacting particles. The way we develop the argument gives as by-product a short account of molecular orbitals and molecular vibrations.

High-frequency homogenization for travelling waves in periodic media.

Science.gov (United States)

Harutyunyan, Davit; Milton, Graeme W; Craster, Richard V

2016-07-01

We consider high-frequency homogenization in periodic media for travelling waves of several different equations: the wave equation for scalar-valued waves such as acoustics; the wave equation for vector-valued waves such as electromagnetism and elasticity; and a system that encompasses the Schrödinger equation. This homogenization applies when the wavelength is of the order of the size of the medium periodicity cell. The travelling wave is assumed to be the sum of two waves: a modulated Bloch carrier wave having crystal wavevector [Formula: see text] and frequency ω 1 plus a modulated Bloch carrier wave having crystal wavevector [Formula: see text] and frequency ω 2 . We derive effective equations for the modulating functions, and then prove that there is no coupling in the effective equations between the two different waves both in the scalar and the system cases. To be precise, we prove that there is no coupling unless ω 1 = ω 2 and [Formula: see text] where Λ =(λ 1 λ 2 …λ d ) is the periodicity cell of the medium and for any two vectors [Formula: see text] the product a ⊙ b is defined to be the vector ( a 1 b 1 , a 2 b 2 ,…, a d b d ). This last condition forces the carrier waves to be equivalent Bloch waves meaning that the coupling constants in the system of effective equations vanish. We use two-scale analysis and some new weak-convergence type lemmas. The analysis is not at the same level of rigour as that of Allaire and co-workers who use two-scale convergence theory to treat the problem, but has the advantage of simplicity which will allow it to be easily extended to the case where there is degeneracy of the Bloch eigenvalue.

Reflection and transmission of light at periodic layered metamaterial films

Science.gov (United States)

Paul, Thomas; Menzel, Christoph; Śmigaj, Wojciech; Rockstuhl, Carsten; Lalanne, Philippe; Lederer, Falk

2011-09-01

The appropriate description of light scattering (transmission/reflection) at a bulky artificial medium, consisting of a sequence of functional metamaterial and natural material films, represents a major challenge in current theoretical nano-optics. Because in many relevant cases, in particular, in the optical domain, a metamaterial must not be described by an effective permittivity and permeability the usual Fresnel formalism cannot be applied. A reliable alternative consists in using a Bloch mode formalism known, e.g., from the theory of photonic crystals. It permits to split this complex issue into two more elementary ones, namely the study of light propagation in an infinitely extended metamaterial and the analysis of light scattering at interfaces between adjacent meta and natural materials. The first problem is routinely solved by calculating the relevant Bloch modes and their dispersion relations. The second task is more involved and represents the subject of the present study. It consists in using the general Bloch mode orthogonality to derive rigorous expressions for the reflection and transmission coefficients at an interface between two three-dimensional absorptive periodic media for arbitrary incidence. A considerable simplification can be achieved if only the fundamental Bloch modes of both media govern the scattering properties at the interface. If this approximation is valid, which depends on the longitudinal metamaterial period, the periodic metamaterial may be termed homogeneous. Only in this case the disentanglement of the fundamental modes of both media can be performed and the reflection/transmission coefficients can be expressed in terms of two impedances, each depending solely on the properties of the fundamental mode of the respective medium. In order to complement the picture, we apply the present formalism to the quite general problem of reflection/transmission at a metamaterial film sandwiched between a dissimilar metamaterial. This

Excitonic magnet in external field: Complex order parameter and spin currents

Science.gov (United States)

Geffroy, D.; Hariki, A.; Kuneš, J.

2018-04-01

We investigate spin-triplet exciton condensation in the two-orbital Hubbard model close to half-filling by means of dynamical mean-field theory. Employing an impurity solver that handles complex off-diagonal hybridization functions, we study the behavior of excitonic condensate in stoichiometric and doped systems subject to external magnetic field. We find a general tendency of the triplet order parameter to lie perpendicular with the applied field and identify exceptions from this rule. For solutions exhibiting k -odd spin textures, we discuss the Bloch theorem, which, in the absence of spin-orbit coupling, forbids the appearance of spontaneous net spin current. We demonstrate that the Bloch theorem is not obeyed by the dynamical mean-field theory.

Current stopping power analyses

International Nuclear Information System (INIS)

Porter, L.E.

1983-01-01

Modified Bethe-Bloch stopping power theory permits fairly accurate calculation of energy losses over a broad interval of projectile velocity v = νc insofar as several parameters appearing in the revised Bethe-Bloch formula have been corectly evaluated. Since the parameters cannot in general be ascertained by calculation from first principles, fits of theory to measurement remain the best method of evaluation. The parameters alluded to are: the target mean excitation energy; the shell correction scaling parameters; the composite single free parameter of the Barkas (projectile-z 3 ) effect correction formalism, and the strength of the correction term; the high velocity density effect correction parameter; and the low velocity charge state parameter. These parameters are discussed

Magnetic phenomena in F.F.A.G. cyclotrons; Phenomenes magnetiques dans les cyclotrons F.F.A.G

Energy Technology Data Exchange (ETDEWEB)

Beurtey, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-07-01

This study regroups and develops some experimental and theoretical results obtained with spiral tract cyclotrons. The method used has been studied previously by C. BLOCH, whom we thank for his helpful advice. We have tried to give the main useful results, which are also in accordance with the rather scarce experimental results obtained on spiral pole pieces. (author) [French] Cette etude regroupe et developpe des resultats experimentaux et theoriques sur les cyclotrons 'spirales'. La methode employee est celle etudiee par C. BLOCH, que nous remercions vivement pour sa bienveillance et ses conseils. Nous avons essaye de donner les resultats essentiels a la fois utilisables et compatibles avec les resultats experimentaux peu nombreux sur les pieces polaires spiralees. (auteur)

Geometric phase for N-level systems through unitary integration

International Nuclear Information System (INIS)

Uskov, D. B.; Rau, A. R. P.

2006-01-01

Geometric phases are important in quantum physics and are now central to fault-tolerant quantum computation. For spin 1/2, the Bloch sphere S 2 , together with a U(1) phase, provides a complete SU(2) description. We generalize to N-level systems and SU(N) in terms of a 2(N-1)-dimensional base space and reduction to a (N-1)-level problem, paralleling closely the two-dimensional case. This iteratively solves the time evolution of an N-level system and gives (N-1) geometric phases explicitly. A complete analytical construction of an S 4 Bloch-like sphere for two qubits is given for the Spin(5) or SO(5) subgroup of SU(4)

Generation of phase-covariant quantum cloning

International Nuclear Information System (INIS)

Karimipour, V.; Rezakhani, A.T.

2002-01-01

It is known that in phase-covariant quantum cloning, the equatorial states on the Bloch sphere can be cloned with a fidelity higher than the optimal bound established for universal quantum cloning. We generalize this concept to include other states on the Bloch sphere with a definite z component of spin. It is shown that once we know the z component, we can always clone a state with a fidelity higher than the universal value and that of equatorial states. We also make a detailed study of the entanglement properties of the output copies and show that the equatorial states are the only states that give rise to a separable density matrix for the outputs

The algebraic geometry of Harper operators

Science.gov (United States)

Li, Dan

2011-10-01

Following an approach developed by Gieseker, Knörrer and Trubowitz for discretized Schrödinger operators, we study the spectral theory of Harper operators in dimensions 2 and 1, as a discretized model of magnetic Laplacians, from the point of view of algebraic geometry. We describe the geometry of an associated family of Bloch varieties and compute their density of states. Finally, we also compute some spectral functions based on the density of states. We discuss the difference between the cases with rational or irrational parameters: for the two-dimensional Harper operator, the compactification of the Bloch variety is an ordinary variety in the rational case and an ind-pro-variety in the irrational case. This gives rise, at the algebro-geometric level of Bloch varieties, to a phenomenon similar to the Hofstadter butterfly in the spectral theory. In dimension 2, the density of states can be expressed in terms of period integrals over Fermi curves, where the resulting elliptic integrals are independent of the parameters. In dimension 1, for the almost Mathieu operator, with a similar argument, we find the usual dependence of the spectral density on the parameter, which gives rise to the well-known Hofstadter butterfly picture.

Clustering phenomena in nuclear matter below the saturation density

International Nuclear Information System (INIS)

Takemoto, Hiroki; Fukushima, Masahiro; Chiba, Satoshi; Horiuchi, Hisashi; Akaishi, Yoshinori; Tohsaki, Akihiro

2004-01-01

We investigate density-fluctuated states of nuclear matter as a result of clustering below the saturation density ρ 0 by description in terms of the Bloch function. The Bloch description has the advantage of a unified representation for a density-fluctuated state from an aggregate of uncorrelated clusters in extremely low-density regions to the plane-wave state of uniform matter in relatively high-density regions. We treat the density-fluctuated states due to α and 16 O clustering in symmetric nuclear matter and due to 10 He clustering in asymmetric nuclear matter. The density-fluctuated states develop as the density of matter decreases below each critical density around 0.2-0.4 ρ 0 which depends on what kind of effective force we use

On the treatment of light-ion electronic stopping in dense matter

Energy Technology Data Exchange (ETDEWEB)

Schiwietz, G. (Hahn-Meitner-Inst. Berlin GmbH, Div., FD (Germany)); Grande, P.L. (Hahn-Meitner-Inst. Berlin GmbH, Div., FD (Germany))

1994-05-01

A review is given on single-electron mechanisms and the corresponding theoretical approaches describing the electronic energy-transfer processes of light ions in gases and solids. Special emphasis is given to a discussion on the connection between exact Bloch-wave treatments and free-atom approximations. In the case of solids, perturbation theory is applied to the stopping of low-energy ions in the alkaline metals Li and Na. These calculations include Bloch wavefunctions of the Wigner-Seitz type obtained from a Hartree-Fock-Slater calculation and allow for a prediction of the mean energy loss under channeling conditions. Results of the most widely used local-density approximation are compared to data of our more complete perturbative treatment. Comparison is also made with recent LCAO calculations. (orig.)

Optically Controlled Quantum Dot Spins for Scaleable Quantum Computing

National Research Council Canada - National Science Library

Steel, Duncan G

2005-01-01

.... Our main achievements include working with a model system based on the exciton optical Bloch vector where we demonstrated the first solid state quantum logic device and made the first demonstration...

BAFRA BALIK GÖLÜ'NDE YAŞAYAN HAVUZ BALIĞI,Carassius gibelio (BLOCH, 1782'NUN KONDİSYON FAKTÖRÜ VE BOY-AĞIRLIK İLİŞKİSİNİN BELİRLENMESİ

Directory of Open Access Journals (Sweden)

Derya BOSTANCI

2009-02-01

Full Text Available Özet: Bu çalışmada, Bafra Balık Gölü'ndeki Havuz balığının (Carassius gibelio kondisyon faktörü ve boy-ağırlık ilişkisini belirlemek amacıyla, Ocak 2000-Eylül 2002 tarihleri arasında aylık olarak örneklenen 173 birey incelenmiştir. Populasyonda 168 ♀ (% 97.11, 5 ♂ (% 2.89 birey bulunmaktadır. Populasyonun çatal boy dağılımı 16.9-30 cm arasında, ağırlık dağılımı ise 125-730 g arasında değişmiş, boy-ağırlık ilişkisi W = 0.0265 L2,978 olarak hesaplanmıştır. Kondisyon faktörü ise 1.976–3.776 arasında değişmiş ve ortalama kondisyon faktörü 2.494±0.018 olarak belirlenmiştir. Anahtar kelimeler: Carassius gibelio, Kondisyon faktörü, Boy-ağırlık ilişkisi, Bafra Balık Gölü DETERMINATION OF CONDITION FACTOR AND LENGTH-WEİGHT RELATIONSHIP OF THE CRUCIAN CARP, Carassıus gıbelıo (BLOCH, 1782 INHABITING BAFRA FISH LAKE Abstract: In this study, it is examined the crucian carp (Carassius gibelio which is captured by montly sampling during the period of January 2000 to September 2002 in the Bafra Fish Lake to investigate for the condition factor and length-weight relationship. There are 168 ♀ (% 97.11, 5 ♂ (% 2.89 specimens in the population. The fork length distribution from 16.9 to 30 cm and weight varied between of 125 to 730 g; length-weight relationship was calculated as W = 0.0265 L2.978. Condition factors varied from 1.976 to 3.776 and the mean condition factors were determined as 2.494±0.018. Key words: Carassius gibelio, Condition factor, Length-weight relationship, Bafra Fish Lake

Particle size, spin wave and surface effects on magnetic properties of MgFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Aslibeiki, B., E-mail: b.aslibeiki@tabrizu.ac.ir [Department of Physics, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Varvaro, G.; Peddis, D. [Istituto di Struttura della Materia, National Research Council, Monterotondo Scalo, Roma 00015 (Italy); Kameli, P. [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2017-01-15

Magnesium ferrite, MgFe{sub 2}O{sub 4}, nanoparticles with a mean diameter varying from ∼6 to ∼17 nm were successfully synthesized using a simple thermal decomposition method at different annealing temperatures ranging in between 400 and 600 °C. Pure spinel ferrite nanoparticles were obtained at temperatures lower than 500 °C, while the presence of hematite (α-Fe{sub 2}O{sub 3}) impurities was observed at higher temperatures. Single-phase samples show a superparamagnetic behavior at 300 K, the saturation magnetization (M{sub s}) becoming larger with the increase of particles size. The temperature dependence of M{sub s} was explained in terms of surface spin-canting as well as spin wave excitations in the core. Using a modified Bloch law, [M{sub s}(T)=M{sub s}(0)(1−βT{sup α})], we observed a size dependent behavior of the Bloch constant β and the exponent α, whose values increase and decrease, respectively, as the particle size reduces. - Highlights: • MgFe{sub 2}O{sub 4} nanoparticles were synthesized using a thermal decomposition method. • Pure ferrite nanoparticles were obtained at temperatures lower than 500 °C. • Samples show a superparamagnetic behavior at room temperatures. • Spin wave excitations were studied using a modified Bloch law.

Coherent dynamics in semiconductors

DEFF Research Database (Denmark)

Hvam, Jørn Märcher

1998-01-01

enhanced in quantum confined lower-dimensional systems, where exciton and biexciton effects dominate the spectra even at room temperature. The coherent dynamics of excitons are at modest densities well described by the optical Bloch equations and a number of the dynamical effects known from atomic......Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

Reactively sputtered epitaxial γ′-Fe4N films: Surface morphology, microstructure, magnetic and electrical transport properties

KAUST Repository

Mi, Wenbo

2013-10-01

Epitaxial γ′-Fe4N films with (1 0 0) and (1 1 0) orientations have been fabricated by reactive sputtering; these films were characterized by X-ray θ-2θ and φ scans, pole figures and high-resolution transmission electron microscopy. The film surface is very smooth as the film is less than 58 nm thick. The films exhibit soft ferromagnetism, and the saturation magnetization decreases with an increase in temperature, following Bloch\\'s spin wave theory. The films also exhibit a metallic conductance mechanism. Below 30 K, magnetoresistance (MR) is positive and increases linearly with the applied field in the high-field range. In the low-field range, MR increases abruptly. Above 30 K, MR is negative, and its value increases linearly with the applied field.

Critical voltage effects in electron channeling patterns

International Nuclear Information System (INIS)

Farrow, R.C.

1984-01-01

Electron channeling patterns were used to study critical voltage effects in the metals molybdenum and tungsten. The purpose was to characterize both theoretically and experimentally how a critical voltage will affect the channeling pattern line shapes. The study focused on the second order critical voltage that results from the degeneracy between the Bloch wave states of the (110) and (220) reflections. Theoretical (110) series electron channeling pattern line profiles were calculated using the dynamical theory of Hirsch and Humphreys (1970). A 10 beam dynamical electron diffraction calculation was performed (using complex Fourier lattice potentials) to generate Bloch wave coefficients, excitation amplitudes, and absorption coefficients needed for determining backscattering coefficients and subsequent backscattered electron intensities. The theoretical model is applicable to electron diffraction at all energies since no high energy approximation or perturbation method was used

Broadband slow light in one-dimensional logically combined photonic crystals.

Science.gov (United States)

Alagappan, G; Png, C E

2015-01-28

Here, we demonstrate the broadband slow light effects in a new family of one dimensional photonic crystals, which are obtained by logically combining two photonic crystals of slightly different periods. The logical combination slowly destroys the original translational symmetries of the individual photonic crystals. Consequently, the Bloch modes of the individual photonic crystals with different wavevectors couple with each other, creating a vast number of slow modes. Specifically, we describe a photonic crystal architecture that results from a logical "OR" mixture of two one dimensional photonic crystals with a periods ratio of r = R/(R - 1), where R > 2 is an integer. Such a logically combined architecture, exhibits a broad region of frequencies in which a dense number of slow modes with varnishing group velocities, appear naturally as Bloch modes.

Alpha-chain states in 4N-nuclei from 20Ne to 32S

International Nuclear Information System (INIS)

Merchant, A.C.; Rae, W.D.M.

1992-01-01

A 6α-chain state has recently been discovered in 24 Mg which is some 16--17 MeV above the 6α-breakup threshold and yet paradoxically only 4--5 MeV wide. This surprising discovery raises the question of the possible existence of Nα-chain states in other 4N-nuclei. The excitation energy of this 6α-chain state is very close to the value predicted by the Bloch-Brink cluster model. Therefore, to aid the experimental search for similar states in other nuclei, we present here predictions of the excitation energies of the Nα-chain state bandheads in the 4N-nuclei from 20 Ne to 32 S obtained using the Bloch-Brink cranked cluster model with the Brink-Boeker effective interaction and free variation of all parameters

Impact of slow-light enhancement on optical propagation in active semiconductor photonic crystal waveguides

DEFF Research Database (Denmark)

Chen, Yaohui; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

2015-01-01

We derive and validate a set of coupled Bloch wave equations for analyzing the reflection and transmission properties of active semiconductor photonic crystal waveguides. In such devices, slow-light propagation can be used to enhance the material gain per unit length, enabling, for example......, the realization of short optical amplifiers compatible with photonic integration. The coupled wave analysis is compared to numerical approaches based on the Fourier modal method and a frequency domain finite element technique. The presence of material gain leads to the build-up of a backscattered field, which...... is interpreted as distributed feedback effects or reflection at passive-active interfaces, depending on the approach taken. For very large material gain values, the band structure of the waveguide is perturbed, and deviations from the simple coupled Bloch wave model are found....

and Asian catfish, Clarias batrachus

African Journals Online (AJOL)

ALEX

2013-02-27

Feb 27, 2013 ... crossing Indian catfish, Heteropneustes fossilis (Bloch) and Asian catfish, Clarias batrachus (Linn.) by ... Extensive culture of H. fossilis is prevalent in India, but with less growth, when ..... Kligerman AD, Bloom SE (1977).

A general multiscale framework for the emergent effective elastodynamics of metamaterials

Science.gov (United States)

Sridhar, A.; Kouznetsova, V. G.; Geers, M. G. D.

2018-02-01

This paper presents a general multiscale framework towards the computation of the emergent effective elastodynamics of heterogeneous materials, to be applied for the analysis of acoustic metamaterials and phononic crystals. The generality of the framework is exemplified by two key characteristics. First, the underlying formalism relies on the Floquet-Bloch theorem to derive a robust definition of scales and scale separation. Second, unlike most homogenization approaches that rely on a classical volume average, a generalized homogenization operator is defined with respect to a family of particular projection functions. This yields a generalized macro-scale continuum, instead of the classical Cauchy continuum. This enables (in a micromorphic sense) to homogenize the rich dispersive behavior resulting from both Bragg scattering and local resonance. For an arbitrary unit cell, the homogenization projection functions are constructed using the Floquet-Bloch eigenvectors obtained in the desired frequency regime at select high symmetry points, which effectively resolves the emergent phenomena dominating that regime. Furthermore, a generalized Hill-Mandel condition is proposed that ensures power consistency between the homogenized and full-scale model. A high-order spatio-temporal gradient expansion is used to localize the multiscale problem leading to a series of recursive unit cell problems giving the appropriate micro-mechanical corrections. The developed multiscale method is validated against standard numerical Bloch analysis of the dispersion spectra of example unit cells encompassing multiple high-order branches generated by local resonance and/or Bragg scattering.

TM-TE hybridization and tunable refraction in magnetophotonic crystals

Energy Technology Data Exchange (ETDEWEB)

Khanikaev, A.B. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1, Hibari-Ga-Oka, Toyohashi 441-8580 (Japan)]. E-mail: khanikaev@maglab.eee.tut.ac.jp; Inoue, M. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1, Hibari-Ga-Oka, Toyohashi 441-8580 (Japan); Granovsky, A.B. [Faculty of Physics, Lomonosov Moscow State University, Leninski Gory, Moscow 119992 (Russian Federation)

2006-05-15

In the present work we study the photonic band structure (PBS) and the polarization state of the Bloch eigenmodes of a two-dimensional magnetophotonic crystal (MPC) with square lattice formed from magneto-optically (MO) active cylinders. The refraction of light at the boundary of the MPC is analyzed. We found that both-the PBS and eigenmodes of the MPC-are most significantly altered by the MO activity in the vicinity of the degeneracies. For this case we demonstrated the possibility of an abrupt change in the propagation direction of light by the application of a magnetic field. For the Bloch wave vectors and frequencies corresponding to non-degenerate branches, the alteration of the PBS is shown to be negligible and eigenmodes almost completely coincide with linearly TE- and/or TM-polarized eigenmodes of the non-magnetic photonic crystal.

TM-TE hybridization and tunable refraction in magnetophotonic crystals

International Nuclear Information System (INIS)

Khanikaev, A.B.; Inoue, M.; Granovsky, A.B.

2006-01-01

In the present work we study the photonic band structure (PBS) and the polarization state of the Bloch eigenmodes of a two-dimensional magnetophotonic crystal (MPC) with square lattice formed from magneto-optically (MO) active cylinders. The refraction of light at the boundary of the MPC is analyzed. We found that both-the PBS and eigenmodes of the MPC-are most significantly altered by the MO activity in the vicinity of the degeneracies. For this case we demonstrated the possibility of an abrupt change in the propagation direction of light by the application of a magnetic field. For the Bloch wave vectors and frequencies corresponding to non-degenerate branches, the alteration of the PBS is shown to be negligible and eigenmodes almost completely coincide with linearly TE- and/or TM-polarized eigenmodes of the non-magnetic photonic crystal

Incoherent imaging using dynamically scattered coherent electrons

International Nuclear Information System (INIS)

Nellist, P.D.; Pennycook, S.J.

1999-01-01

We use a Bloch wave approach to show that, even for coherent dynamical scattering from a stationary lattice with no absorption, annular dark-field imaging in a scanning transmission electron microscope gives a direct incoherent structure image of the atomic-column positions of a zone-axis-aligned crystal. Although many Bloch waves may be excited by the probe, the detector provides a filtering effect so that the 1s-type bound states are found to dominate the image contrast for typical experimental conditions. We also find that the column intensity is related to the transverse kinetic energy of the 1s states, which gives atomic number, Z, contrast. The additional effects of phonon scattering are discussed, in particular the reasons why phonon scattering is not a prerequisite for transverse incoherence. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Integridad y desprecio. Motivos básicos de una concepción de la moral desde la teoría del reconocimiento

Directory of Open Access Journals (Sweden)

Hünneth, Axel

1992-05-01

Full Text Available Not available.

Si se admite con Emst Bloch que la completa integridad del hombre, su dignidad, sólo se alcanza estableciendo una adecuada protección ante los distintos modos de ofensa y de desprecio personal, entonces eso significa a la inversa que la integridad de la persona humana depende constitutivamente de la experiencia de reconocimiento intersubjetivo. El presente texto quiere aclarar esa conexión premisa propia de una teoría normativa del reconocimiento recíproco, entre desprecio e integridad humana que Bloch sugirió pero no desarrolló, para así poder introducir una tesis fuerte de sociología moral: la experiencia del desprecio personal representa un impulso moral en el proceso de desarrollo de la sociedad, pues el progreso moral es el resultado de la lucha por el reconocimiento.

Method to map one-dimensional electronic wave function by using multiple Brillouin zone angle resolved photoemission

Directory of Open Access Journals (Sweden)

Dong-Wook Lee

2010-10-01

Full Text Available Angle resolved photoemission spectroscopy (ARPES is a powerful tool to investigate electronic structures in solids and has been widely used in studying various materials. The electronic structure information by ARPES is obtained in the momentum space. However, in the case of one-dimensional system, we here show that we extract the real space information from ARPES data taken over multiple Brillouin zones (BZs. Intensities in the multiple BZs are proportional to the photoemission matrix element which contains information on the coefficient of the Bloch wave function. It is shown that the Bloch wave function coefficients can be extracted from ARPES data, which allows us to construct the real space wave function. As a test, we use ARPES data from proto-typical one-dimensional system SrCuO2 and construct the real space wave function.

Browse Title Index

African Journals Online (AJOL)

Items 51 - 100 of 286 ... Vol 1 (1998), Bloch's Theorem And Quasiperiodicity In The Theory Of Optical ... Vol 11 (2003), Block Coded Combined Shannon-Fano and GAC Codes ... in Mauritian Transport Sector for Cars and Dual Cars, Abstract PDF.

THE WEIGHTED POINCARÉ DISTANCE IN THE HALF PLANE

OpenAIRE

Byun, Jisoo; Baek, Seung Min; Cho, Hong Rae; Lee, Han-Wool

2014-01-01

In this paper we introduce the weighted Poincaré distance and the induced distance by the weighted Bloch type space. We prove that the weighted Poincaré distance is identical to the inner distance generated by the induced distance.

Debate, Research on E-Cigarettes Continues

Science.gov (United States)

Since they first began to be sold in North America in the mid-2000s, electronic cigarettes have been the subject of intense debate. NCI's Dr. Michele Bloch recently presented an update on some of the issues surrounding e-cigarettes.

RAPD analysis for genetic diversity of two populations of Mystus ...

African Journals Online (AJOL)

) was applied to analyze the genetic variation of the 2 populations of Mystus vittatus (Bloch) of Madhya Pradesh, India. 10 random 10-mer primers were primarily scored in 3 individuals from each of the 2 locations. Five primers, which gave ...

Nonlinear emission from dark anapole modes and route to all-dielectric metamaterial near-field lasers

KAUST Repository

Gongora, J. S. Totero; Miroshnichenko, Andrey E.; Kivshar, Yuri S.; Fratalocchi, Andrea

2016-01-01

By employing ab-initio simulations of Maxwell-Bloch equations with a source of quantum noise, we study a new laser concept based on photonic dark-matter nanostructures that emit only in the near-field, with no far-field radiation pattern

Near-Field Nanolasers based on Nonradiating Anapole Modes

KAUST Repository

Gongora, J. S. Totero; Miroshnichenko, Andrey E.; Kivshar, Yuri S.; Fratalocchi, Andrea

2016-01-01

By employing ab-initio simulations of Maxwell-Bloch equations with a source of quantum noise, we study a new laser concept based on photonic dark-matter nanostructures that emit only in the near-field, with no far-field radiation pattern.

Eelproov Musikvereinile ja "Turangalila-sümfoonia" / Igor Garšnek

Index Scriptorium Estoniae

Garšnek, Igor, 1958-

2010-01-01

Tallinna Filharmoonia hooaja avakontserdist 6. oktoobril Estonia kontserdisaalis, kus esinesid Tallinna Filharmoonikud ja Lisa Smirnova (klaver) Andres Mustoneni dirigeerimisel ja 8. oktoobril samas toimunud ERSO kontserdist Nikolai Aleksejevi dirigeerimisel, kavas Olivier Messiaeni "Turangalila-Sümfoonia", solistid Francois Weigel ja Thomas Bloch

Near-Field Nanolasers based on Nonradiating Anapole Modes

KAUST Repository

Gongora, J. S. Totero

2016-05-31

By employing ab-initio simulations of Maxwell-Bloch equations with a source of quantum noise, we study a new laser concept based on photonic dark-matter nanostructures that emit only in the near-field, with no far-field radiation pattern.

Nonlinear emission from dark anapole modes and route to all-dielectric metamaterial near-field lasers

KAUST Repository

Gongora, J. S. Totero

2016-08-29

By employing ab-initio simulations of Maxwell-Bloch equations with a source of quantum noise, we study a new laser concept based on photonic dark-matter nanostructures that emit only in the near-field, with no far-field radiation pattern

Küünarnukk purustas 1,7 miljardit maksva maali / Aadu Hiietamm

Index Scriptorium Estoniae

Hiietamm, Aadu, 1954-

2006-01-01

Kunstikoguja Steve Wynn lõhkus Las Vegases kogemata Picasso maali "La Reve" ("Unistus"), mille ta oli otsustanud maha müüa 139 miljoni dollari eest. Senine rekordhind - 135 miljonit dollarit - maksti Gustav Klimti portreemaali "Adele Bloch-Bauer I" eest

Quasiconfigurations: an approach to effective forces

International Nuclear Information System (INIS)

Poves, A.; Pasquini, E.; Zuker, A.P.

1978-01-01

Many body effective operators appear naturally by dressing states through a perturbative unitary transformation. They have forms that differ from those obtained in the Bloch-Horowitz approach. The fsub(7/2)sup(n) problem is treated explicitly. Pandya's transforms are generalized

CERN's 25th Anniversary

CERN Multimedia

CERN PhotoLab

1979-01-01

A ceremony in the Main Auditorium on 23 June 1979 to mark the 25th Anniversary of CERN. A photo of the five Director-Generals of CERN, from left to right: John Adams, Willi Jentschke, Felix Bloch, Viki Weisskopf and Leon van Hove.

Plasmonic fluorescence enhancement of DBMBF2 monomers and DBMBF2-toluene exciplexes using al-hole arrays

NARCIS (Netherlands)

Schmidt, T.M.; Bochenkov, V.E.; Espinoza, J.D.A.; Smits, E.C.P.; Muzafarov, A.M.; Kononevich, Y.N.; Sutherland, D.S.

2014-01-01

The optical properties of aluminum hole arrays fabricated via colloidal lithography were investigated. By tuning the hole diameter and hole spacing independently, their influence on the Bloch wave-surface plasmon polariton (BW-SPP) and localized surface plasmon resonances resonances (LSPR) could be

Ethical Ideologies: Do They Affect Shopping Behaviors and Perceptions of Morality?

Science.gov (United States)

Cho, Hyeon; Yoo, Jeong-Ju; Johnson, Kim K. P.

2005-01-01

Counterfeiting is a serious problem facing several industries, including the medical, agricultural, and apparel industries (Bloch, Bush, & Campbell, 1993). The authors investigated whether ethical viewpoints affect perceptions of the morality of particular shopping behaviors, attitudes toward counterfeit products, and intentions to purchase such…

Transitionless driving on adiabatic search algorithm

Energy Technology Data Exchange (ETDEWEB)

Oh, Sangchul, E-mail: soh@qf.org.qa [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Kais, Sabre, E-mail: kais@purdue.edu [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Department of Chemistry, Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)

2014-12-14

We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.

Study of the stopping power and straggling for alpha particles and protons in organic solids, liquids and gases

International Nuclear Information System (INIS)

Haque, A.K.M.; Mohammadi, A.; Nikjoo, H.

1985-01-01

The stopping power and straggling for 5.5 MeV alpha particles in liquid and vapour phases of water, methanol, ethanol, propanol, h-hexane, n-octane and cyclohexane, and those for low energy protons in ethylene, styrene and propylene and their polymers, have been measured. Range-energy data have been fitted with inverse stopping power functions to give the cross sections. In each case, five parameters have been adjusted to obtain the best fit. The value of chi-squared per degree of freedom has been calculated, together with the parameters. The theoretical stopping cross section has been considered employing the Bethe-Bloch expression together with various corrections (shell correction using Walske and Bichsel procedure, Z 1 3 contribution according to Ashley and Bloch correction based on Lindhard formalism). The existence of a phase effect has been clearly demonstrated for the stopping of both alpha particles and protons. (author)

Bandwidth broadening and asymmetric softening of collective spin waves in magnonic crystals

International Nuclear Information System (INIS)

Montoncello, F.; Giovannini, L.

2014-01-01

We investigate the dependence on the applied field of the frequency/wavevector dispersion relations of collective spin waves in arrays of dots, close to a magnetic transition. In particular, we focus on the low frequency “soft” modes in three different cases: end modes in the transition between two different saturated states in ellipses, fundamental mode in the saturated-to-vortex transition in disks, and gyrotropic mode in the vortex-to-saturated transition in disks. Noteworthy, the spin waves with nonzero Bloch wavevector along the direction of the applied field happen to soften earlier than spin waves with a Bloch wavevector along different directions, and this feature is responsible for an asymmetric broadening of the bandwidth along the different lattice directions. This is particularly useful in magnonic/spin-logic device research, if different binary digits are associated to modes with the same cell function but different propagation directions.

An active learning approach to education in MRI technology for the biomedical engineering curriculum

DEFF Research Database (Denmark)

Hanson, Lars G.

2012-01-01

techniques but can also be used for student exercises which may significantly improve the understanding of MRI concepts. The presentation demonstrates software made for the first few minutes of MRI education but focuses mostly on the educational value of the more advanced Bloch Simulator. It is explored how...... sense expressed in the math is in focus. Unfortunately, the nuclear dynamics happen in four dimensions, and are therefore not well suited for illustration on blackboard. 3D movies are more appropriate, but they do not encourage active learning. The typical solution employed by educators is hand waving...... (literally), since arm motions can to a limited extent be used to illustrate nuclear dynamics. Many students find this confusing, however, and students who do not grasp the meaning during lectures, are left in a bad position. For this reason, educational software was developed over the last decade (the Bloch...

Magnetization processes in amorphous R-Co/R'-Co/R-Co sandwiches (R, R'=Y, Nd, Gd, Er)

International Nuclear Information System (INIS)

Dieny, B.; Givord, D.; Ndjaka, J.M.B.; Alameda, J.M.

1990-01-01

Sandwiches consisting of three amorphous layers (R 0.33 ,Co 0.67 )( 1000 A / R ' 0.33 ,Co 0.67 ) 1000 A / (R 0.33 Co 0.67 ) 1000 A , have been prepared by dc triode sputtering (R, R' are rare-earth elements). The systems chosen are such that the bulk magnetization alternates from one layer to the next or the coercivity of each layer is significantly different. Magnetic transitions are observed under field. They have been quantitatively analyzed in terms of successive reversals of magnetization in the different layers. The creation or annihilation of planar Bloch walls parallel to the surface are associated with the magnetic transitions. The wall energy and wall width depend essentially on the competition between exchange energy and Zeeman energy. It is suggested that the existence of such Bloch walls may favor magnetization reversal in thin films by coherent processes

Axial channeling in electron diffraction

International Nuclear Information System (INIS)

Ichimiya, A.; Lehmpfuhl, G.

1978-01-01

Kossel patterns from Silicon and Niobium were obtained with a convergent electron beam. An intensity maximum in the direction of the zone axes [001] and [111] of Nb was interpreted as axial channeling. The intensity distribution in Kossel patterns was calculated by means of the Bloch wave picture of the dynamical theory of electron diffraction. Particularly zone axis patterns were calculated for different substance-energy combinations and they were compared with experimental observations. The intensity distribution in the calculated Kossel patterns was very sensitive to the model of absorption and it was found that a treatment of the absorption close to the model of Humphreys and Hirsch [Phil. Mag. 18, 115 (1968)] gave the best agreement with the experimental observations. Furthermore it is shown which Bloch waves are important for the intensity distribution in the Kossel patterns, how they are absorbed and how they change with energy. (orig.) [de

Simulating a topological transition in a superconducting phase qubit by fast adiabatic trajectories

Science.gov (United States)

Wang, Tenghui; Zhang, Zhenxing; Xiang, Liang; Gong, Zhihao; Wu, Jianlan; Yin, Yi

2018-04-01

The significance of topological phases has been widely recognized in the community of condensed matter physics. The well controllable quantum systems provide an artificial platform to probe and engineer various topological phases. The adiabatic trajectory of a quantum state describes the change of the bulk Bloch eigenstates with the momentum, and this adiabatic simulation method is however practically limited due to quantum dissipation. Here we apply the "shortcut to adiabaticity" (STA) protocol to realize fast adiabatic evolutions in the system of a superconducting phase qubit. The resulting fast adiabatic trajectories illustrate the change of the bulk Bloch eigenstates in the Su-Schrieffer-Heeger (SSH) model. A sharp transition is experimentally determined for the topological invariant of a winding number. Our experiment helps identify the topological Chern number of a two-dimensional toy model, suggesting the applicability of the fast adiabatic simulation method for topological systems.

Wave propagation in structured materials as a platform for effective parameters retrieving

DEFF Research Database (Denmark)

Andryieuski, Andrei; Ha, S.; Sukhorukov, A. A.

MM slab can be considered as a semi-infinite medium. Modelling the one-directional (forward) propagation of the wave inside a metamaterial slab thick enough to avoid transition layers effects and reflection from the rear interface we are able to restore complex refractive index3. Getting the input...... established yet. In this contribution, we present an overview of our activity in EPs retrieving based on observation of wave propagation phenomena in thick (multilayer) MMs. We put a goal to develop a method which is unambiguous, but at the same time simple and straightforward. The idea is that thick enough...... utilization of the Bloch-mode analysis5. The idea is to perform the Bloch mode expansion6 of the field inside the metamaterial slab when it is illuminated with a plane wave incident from vacuum. Then we determine the effective refractive index from the propagation constant of the dominating (fundamental...

Extraordinary Light-Trapping Enhancement in Silicon Solar Cell Patterned with Graded Photonic Super-Crystals

Directory of Open Access Journals (Sweden)

Safaa Hassan

2017-12-01

Full Text Available Light-trapping enhancement in newly discovered graded photonic super-crystals (GPSCs with dual periodicity and dual basis is herein explored for the first time. Broadband, wide-incident-angle, and polarization-independent light-trapping enhancement was achieved in silicon solar cells patterned with these GPSCs. These super-crystals were designed by multi-beam interference, rendering them flexible and efficient. The optical response of the patterned silicon solar cell retained Bloch-mode resonance; however, light absorption was greatly enhanced in broadband wavelengths due to the graded, complex unit super-cell nanostructures, leading to the overlap of Bloch-mode resonances. The broadband, wide-angle light coupling and trapping enhancement mechanism are understood to be due to the spatial variance of the index of refraction, and this spatial variance is due to the varying filling fraction, the dual basis, and the varying lattice constants in different directions.

Minimax estimation of qubit states with Bures risk

Science.gov (United States)

Acharya, Anirudh; Guţă, Mădălin

2018-04-01

The central problem of quantum statistics is to devise measurement schemes for the estimation of an unknown state, given an ensemble of n independent identically prepared systems. For locally quadratic loss functions, the risk of standard procedures has the usual scaling of 1/n. However, it has been noticed that for fidelity based metrics such as the Bures distance, the risk of conventional (non-adaptive) qubit tomography schemes scales as 1/\\sqrt{n} for states close to the boundary of the Bloch sphere. Several proposed estimators appear to improve this scaling, and our goal is to analyse the problem from the perspective of the maximum risk over all states. We propose qubit estimation strategies based on separate adaptive measurements, and collective measurements, that achieve 1/n scalings for the maximum Bures risk. The estimator involving local measurements uses a fixed fraction of the available resource n to estimate the Bloch vector direction; the length of the Bloch vector is then estimated from the remaining copies by measuring in the estimator eigenbasis. The estimator based on collective measurements uses local asymptotic normality techniques which allows us to derive upper and lower bounds to its maximum Bures risk. We also discuss how to construct a minimax optimal estimator in this setup. Finally, we consider quantum relative entropy and show that the risk of the estimator based on collective measurements achieves a rate O(n-1log n) under this loss function. Furthermore, we show that no estimator can achieve faster rates, in particular the ‘standard’ rate n ‑1.

Inverse problem for in vivo NMR spatial localization

International Nuclear Information System (INIS)

Hasenfeld, A.C.

1985-11-01

The basic physical problem of NMR spatial localization is considered. To study diseased sites, one must solve the problem of adequately localizing the NMR signal. We formulate this as an inverse problem. As the NMR Bloch equations determine the motion of nuclear spins in applied magnetic fields, a theoretical study is undertaken to answer the question of how to design magnetic field configurations to achieve these localized excited spin populations. Because of physical constraints in the production of the relevant radiofrequency fields, the problem factors into a temporal one and a spatial one. We formulate the temporal problem as a nonlinear transformation, called the Bloch Transform, from the rf input to the magnetization response. In trying to invert this transformation, both linear (for the Fourier Transform) and nonlinear (for the Bloch Transform) modes of radiofrequency excitation are constructed. The spatial problem is essentially a statics problem for the Maxwell equations of electromagnetism, as the wavelengths of the radiation considered are on the order of ten meters, and so propagation effects are negligible. In the general case, analytic solutions are unavailable, and so the methods of computer simulation are used to map the rf field spatial profiles. Numerical experiments are also performed to verify the theoretical analysis, and experimental confirmation of the theory is carried out on the 0.5 Tesla IBM/Oxford Imaging Spectrometer at the LBL NMR Medical Imaging Facility. While no explicit inverse is constructed to ''solve'' this problem, the combined theoretical/numerical analysis is validated experimentally, justifying the approximations made. 56 refs., 31 figs

Inverse problem for in vivo NMR spatial localization

Energy Technology Data Exchange (ETDEWEB)

Hasenfeld, A.C.

1985-11-01

The basic physical problem of NMR spatial localization is considered. To study diseased sites, one must solve the problem of adequately localizing the NMR signal. We formulate this as an inverse problem. As the NMR Bloch equations determine the motion of nuclear spins in applied magnetic fields, a theoretical study is undertaken to answer the question of how to design magnetic field configurations to achieve these localized excited spin populations. Because of physical constraints in the production of the relevant radiofrequency fields, the problem factors into a temporal one and a spatial one. We formulate the temporal problem as a nonlinear transformation, called the Bloch Transform, from the rf input to the magnetization response. In trying to invert this transformation, both linear (for the Fourier Transform) and nonlinear (for the Bloch Transform) modes of radiofrequency excitation are constructed. The spatial problem is essentially a statics problem for the Maxwell equations of electromagnetism, as the wavelengths of the radiation considered are on the order of ten meters, and so propagation effects are negligible. In the general case, analytic solutions are unavailable, and so the methods of computer simulation are used to map the rf field spatial profiles. Numerical experiments are also performed to verify the theoretical analysis, and experimental confirmation of the theory is carried out on the 0.5 Tesla IBM/Oxford Imaging Spectrometer at the LBL NMR Medical Imaging Facility. While no explicit inverse is constructed to ''solve'' this problem, the combined theoretical/numerical analysis is validated experimentally, justifying the approximations made. 56 refs., 31 figs.

Investigations into homogenization of electromagnetic metamaterials

DEFF Research Database (Denmark)

Clausen, Niels Christian Jerichau

This dissertation encompasses homogenization methods, with a special interest into their applications to metamaterial homogenization. The first method studied is the Floquet-Bloch method, that is based on the assumption of a material being infinite periodic. Its field can then be expanded in term...

Infrared phenomena in quantum electrodynamics : I. The physical one-electron states in the infrared region

NARCIS (Netherlands)

Haeringen, W. van

In view of remaining obscurities and difficulties in existing treatments of the infrared divergences in quantum electrodynamics this problem has been considered anew. The approximate model introduced in 1937 by Bloch and Nordsieck is rediscussed. It is explicitly shown to be a good substitute for

Re-Engineering the Stomatopod Eye, Nature’s Most Comprehensive Visual Sensor

Science.gov (United States)

2017-02-22

evolutionary trajectory for the past 400 million years. We want to learn from this evolutionarily based design. As their closest existing, artificial...of the Anterior Cruciate Ligament. The American Journal of Sports Medicine 0363546514566192. T. Charanya, T. York, S. Bloch, G. Sudlow, R. Tang, W

Carrier-carrier relaxation kinetics in quantum well semiconductor structures with nonparabolic energy bands

DEFF Research Database (Denmark)

Dery, H.; Tromborg, Bjarne; Eisenstein, G.

2003-01-01

We describe carrier-carrier scattering dynamics in an inverted quantum well structure including the nonparabolic nature of the valance band. A solution of the semiconductor Bloch equations yields strong evidence to a large change in the temporal evolution of the carrier distributions compared to ...

Quantum dynamical phenomena of independent electrons in semiconductor superlattices subject to a uniform electric field

International Nuclear Information System (INIS)

Bouchard, A.M.

1994-01-01

This report discusses the following topics: Bloch oscillations and other dynamical phenomena of electrons in semiconductor superlattices; solvable dynamical model of an electron in a one-dimensional aperiodic lattice subject to a uniform electric field; and quantum dynamical phenomena of electrons in aperiodic semiconductor superlattices

Bird of Passage at Four Universities

Indian Academy of Sciences (India)

IAS Admin

ship in the Research Department of a telephone com- pany, `Mix and .... the way he could guide research students. He always .... On his advice Peierls left ..... ciple fill the Bloch states, giving us a metal or an insulator (Figures 1a and 1b),.

Multiscale mechanics of dynamical metamaterials

NARCIS (Netherlands)

Geers, M.G.D.; Kouznetsova, V.; Sridhar, A.; Krushynska, A.; Kleiber, M.; Burczynski, T.; Wilde, K.; Gorski, J.; Winkelmann, K.; Smakosz, L.

2016-01-01

This contribution focuses on the computational multi-scale solution of wave propagation phenomena in dynamic metamaterials. Taking the Bloch-Floquet solution for the standard elastic case as a point of departure, an extended scheme is presented to solve for heterogeneous visco-elastic materials. The

Nonrandom variation in Poecilia marcellinoi n. sp. and P. salvatoris Regan, 1907 in El Salvador (Pisces, Poeciliidae)

NARCIS (Netherlands)

Poeser, Frederick N.

1995-01-01

A new species of the genus Poecilia Bloch & Schneider, 1801 is recorded from El Salvador. Morphological and meristic data of P. marcellinoi n. sp. and of the sympatric P. salvatoris Regan, 1907 are analysed. Intra- and interspecific variation are compared and correlated with environmental and

Unified Approach to Universal Cloning and Phase-Covariant Cloning

OpenAIRE

Hu, Jia-Zhong; Yu, Zong-Wen; Wang, Xiang-Bin

2008-01-01

We analyze the problem of approximate quantum cloning when the quantum state is between two latitudes on the Bloch's sphere. We present an analytical formula for the optimized 1-to-2 cloning. The formula unifies the universal quantum cloning (UQCM) and the phase covariant quantum cloning.

YBa2Cu3O7–La0.67Sr0.33MnO3 trilayers

Indian Academy of Sciences (India)

the near bulk value (~350 K) in films thicker than 200 Å, while thinner films show a slight drop in ... 1000 Oe field-cooled Ms(T) measurements (shown in figure 1) to the Bloch relation .... The solid lines in the inset are only guides to the eyes.

Length-weight relationships of five fish species in Epe lagoon, Nigeria

African Journals Online (AJOL)

The fishes (Clarias gariepinus (Burch), Illisha africana Bloch), Chrysichthys nigrodigitatus (Lacepede), Chrysichthys walkeri (Gunther) and Ethmalosa fimbriata (Bowdich)) were obtained from fish landing site at Epe market from November 2001 to October 2002, and January to December 2003. The parameters a and b of the ...

Roundtrip matrix method for calculating the leaky resonant modes of open nanophotonic structures

DEFF Research Database (Denmark)

de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper

2014-01-01

We present a numerical method for calculating quasi-normal modes of open nanophotonic structures. The method is based on scattering matrices and a unity eigenvalue of the roundtrip matrix of an internal cavity, and we develop it in detail with electromagnetic fields expanded on Bloch modes...

Data systems and computer science space data systems: Onboard memory and storage

Science.gov (United States)

Shull, Tom

1991-01-01

The topics are presented in viewgraph form and include the following: technical objectives; technology challenges; state-of-the-art assessment; mass storage comparison; SODR drive and system concepts; program description; vertical Bloch line (VBL) device concept; relationship to external programs; and backup charts for memory and storage.

Method to map individual electromagnetic field components inside a photonic crystal

NARCIS (Netherlands)

Denis, T.; Reijnders, B.; Lee, J.H.H.; van der Slot, Petrus J.M.; Vos, Willem L.; Boller, Klaus J.

2012-01-01

We present a method to map the absolute electromagnetic field strength inside photonic crystals. We apply the method to map the dominant electric field component Ez of a two-dimensional photonic crystal slab at microwave frequencies. The slab is placed between two mirrors to select Bloch standing

Spectrum properties of electrons in solids

International Nuclear Information System (INIS)

Avron, J.

1975-11-01

The electron spectra in the one-particle Bloch model is discussed. The presence of hamiltonian bands is proved, especially for the Dirac and Schrodinger hamiltonians. The analyticity of the quasimomentum k is described as well as the stability of the bands in singular disturbances. (B.G.)

The Faraday effect revisited

DEFF Research Database (Denmark)

Cornean, Horia; Nenciu, Gheorghe

2009-01-01

This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant. The main mathematical tool is a regularized magnetic and geometric...

Joint Force Quarterly. Number 12, Summer 1996

Science.gov (United States)

1996-08-01

Editor Martin J. Peters, Jr. Production Coordinator Calvin B. Kelley Copy Editor The Typography and Design Division of the U.S. Government Printing...mirror imaging of the worst sort. Immediately after the defeat of France in 1940, historian Marc Bloch (a French reserve officer who observed the

A Higgs at 125.1 GeV and baryon mass spectra derived from a Common U(3) Lie group framework

DEFF Research Database (Denmark)

Trinhammer, Ole; Bohr, Henrik; Jensen, Mogens O Stibius

2015-01-01

Baryons are described by a Hamiltonian on an intrinsic U(3) Lie group configuration space with electroweak degrees of freedom originating in specific Bloch wave factors. By opening the Bloch degrees of freedom pairwise via a U(2) Higgs mechanism, the strong and electroweak energy scales become...... related to yield the Higgs mass 125.085+/-0.017 GeV and the usual gauge boson masses. From the same Hamiltonian we derive both the relative neutron to proton mass ratio and the N and Delta mass spectra. All compare rather well with the experimental values. We predict neutral flavour baryon singlets...... to be sought for in negative pions scattering on protons or in photoproduction on neutrons and in invariant mass like Σ+c(2455)D- from various decays above the open charm threshold, e.g. at 4499, 4652 and 4723 MeV. The fundamental predictions are based on just one length scale and the fine structure coupling...

Dissipative effects in Multilevel Systems

Energy Technology Data Exchange (ETDEWEB)

Solomon, A I [Department of Physics and Astronomy, Open University, Milton Keynes MK7 6AA (United Kingdom); Schirmer, S G [Department of Applied Maths and Theoretical Physics, University of Cambridge, Cambridge, CB3 0WA (United Kingdom)

2007-11-15

Dissipation is sometimes regarded as an inevitable and regrettable presence in the real evolution of a quantum system. However, the effects may not always be malign, although often non-intuitive and may even be beneficial. In this note we we display some of these effects for N-level systems, where N = 2,3,4. We start with an elementary introduction to dissipative effects on the Bloch Sphere, and its interior, the Bloch Ball, for a two-level system. We describe explicitly the hamiltonian evolution as well as the purely dissipative dynamics, in the latter case giving the t {yields} {infinity} limits of the motion. This discussion enables us to provide an intuitive feeling for the measures of control-reachable states. For the three-level case we discuss the impossibility of isolating a two-level (qubit) subsystem; this is a Bohm-Aharonov type consequence of dissipation. We finally exemplify the four-level case by giving constraints on the decay of two-qubit entanglement.

Hydrogenated amorphous silicon nitride photonic crystals for improved-performance surface electromagnetic wave biosensors.

Science.gov (United States)

Sinibaldi, Alberto; Descrovi, Emiliano; Giorgis, Fabrizio; Dominici, Lorenzo; Ballarini, Mirko; Mandracci, Pietro; Danz, Norbert; Michelotti, Francesco

2012-10-01

We exploit the properties of surface electromagnetic waves propagating at the surface of finite one dimensional photonic crystals to improve the performance of optical biosensors with respect to the standard surface plasmon resonance approach. We demonstrate that the hydrogenated amorphous silicon nitride technology is a versatile platform for fabricating one dimensional photonic crystals with any desirable design and operating in a wide wavelength range, from the visible to the near infrared. We prepared sensors based on photonic crystals sustaining either guided modes or surface electromagnetic waves, also known as Bloch surface waves. We carried out for the first time a direct experimental comparison of their sensitivity and figure of merit with surface plasmon polaritons on metal layers, by making use of a commercial surface plasmon resonance instrument that was slightly adapted for the experiments. Our measurements demonstrate that the Bloch surface waves on silicon nitride photonic crystals outperform surface plasmon polaritons by a factor 1.3 in terms of figure of merit.

Lecture at the Globe | "From the Higgs boson to the search for new physics: the prospects for the LHC programme at CERN"

CERN Multimedia

2013-01-01

Christmas lecture (in French, with simultaneous interpreting into English): "From the Higgs boson to the search for new physics: the prospects for the LHC programme at CERN", by Philippe Bloch.   Globe of Science and Innovation Route de Meyrin, 1211 Genève Monday 16 December 2013 at 8:30 p.m. The discovery of the Higgs boson, which was the subject of this year's Nobel prize for physics, has brought us the missing piece of the Standard Model of particle physics. However, many observations (such as the predominance of matter over antimatter in the Universe, the existence of dark matter observed by cosmologists and even the fact that the Higgs boson has a relatively small mass) underline that our knowledge of the structure of matter and its interactions is incomplete.   A wide-ranging programme of research spanning several decades to come thus awaits us at the LHC. Philippe Bloch will begin his lecture by giving us the latest news on the Higg...

Strong photonic crystal behavior in regular arrays of core-shell and quantum disc InGaN/GaN nanorod light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Lewins, C. J., E-mail: c.j.lewins@bath.ac.uk; Le Boulbar, E. D.; Lis, S. M.; Shields, P. A.; Allsopp, D. W. E., E-mail: d.allsopp@bath.ac.uk [Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Edwards, P. R.; Martin, R. W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2014-07-28

We show that arrays of emissive nanorod structures can exhibit strong photonic crystal behavior, via observations of the far-field luminescence from core-shell and quantum disc InGaN/GaN nanorods. The conditions needed for the formation of directional Bloch modes characteristic of strong photonic behavior are found to depend critically upon the vertical shape of the nanorod sidewalls. Index guiding by a region of lower volume-averaged refractive index near the base of the nanorods creates a quasi-suspended photonic crystal slab at the top of the nanorods which supports Bloch modes. Only diffractive behavior could be observed without this region. Slab waveguide modelling of the vertical structure shows that the behavioral regime of the emissive nanorod arrays depends strongly upon the optical coupling between the nanorod region and the planar layers below. The controlled crossover between the two regimes of photonic crystal operation enables the design of photonic nanorod structures formed on planar substrates that exploit either behavior depending on device requirements.

On the unambiguous determination of effective optical properties of periodic metamaterials: a one-dimensional case study

DEFF Research Database (Denmark)

Mortensen, Asger; Yan, Min; Sigmund, Ole

2010-01-01

We show how branch ambiguities in the extraction of effective parameters is arising as a direct consequence of the underlying Bloch state physics. The mutual importance of the different branches in general depends on the experimental context, and we show how the Fourier spectrum of the field inside...

Significance of sterol structural specificity : desmosterol cannot replace cholesterol in lipid rafts

NARCIS (Netherlands)

Vainio, S.; Jansen, Maurice; Koivusalo, M.; Róg, T.; Karttunen, M.E.J.; Vattulainen, I.; Ikonen, E.

2006-01-01

Desmosterol is an immediate precursor of cholesterol in the Bloch pathway of sterol synthesis and an abundant membrane lipid in specific cell types. The significance of the difference between the two sterols, an additional double bond at position C24 in the tail of desmosterol, is not known. Here,

Author Details

African Journals Online (AJOL)

Sairkar, P. Vol 8, No 14 (2009) - Articles Genetic variability in Asparagus racemosus (Willd.) from Madhya Pradesh, India by random amplified polymorphic DNA Abstract PDF · Vol 8, No 17 (2009) - Articles RAPD analysis for genetic diversity of two populations of Mystus vittatus (Bloch) of Madhya Pradesh, India

Ultrafast dynamic optical prop erties of graphene%石墨烯超快动态光学性质∗

Institute of Scientific and Technical Information of China (English)

金芹; 董海明; 韩奎; 王雪峰

2015-01-01

Graphene exhibits excellent ultrafast optical properties due to its unique electronic structure. In this paper we investigate theoretically the ultrafast dynamic optical properties of graphene based on the Bloch-equations, and introduce the theoretical model of graphene. First, we give the energy which has a linear relationship with the wave vector k. The behavior of electrons in the vicinity of the two Dirac points can be described by the massless Dirac-equation, thus we have the Dirac equation of graphene. Second, we discuss the interaction between graphene and light field. The Bloch-equations of graphene are obtained through the Heisenberg equation and then we discuss the photon carriers ,electric polarization and optical current change over time by analyzing the Bloch-equations. It is found that the nonequilibrium carriers in graphene induced by a terahertz field can be built in 20–200 fs due to the Pauli blocking and the conservation of energy principle. The photon carrier density will increase with the frequency of enhanced light field. Thus an optical current can be created rapidly within 1 ps. A graphene system responds linearly to the external optical field for √2evFE0t≪~ω, while the graphene systems respond nonlinearly to the external optical field, where E0 andωare respectively the intensity and the frequency of the light, t is the time and vF the Dirac velocity in graphene. The electric polarization and optical current increase with increasing photon energies. These theoretical results are in agreement with recent experimental findings and indicate that graphene exhibits important features and has practical applications in the ultrafast optic filed, especially in terahertz field.

Anisotropy and multi-band effects in weak-coupling superconductors

International Nuclear Information System (INIS)

Berger, T.L.

1977-01-01

The techniques of second quantization and thermodynamic Green functions are used to investigate energy gap anisotropy and multi-band effects in pure, single-crystal, weak-coupling superconductors. A generalized version of the standard Gorkov factorization is used to linearize the Green functions equations of motion. The effects of lattice periodicity and band structure are taken into account by means of Bloch wave expansions and Bloch transforms. A pairing selection rule is derived which indicates the possibility of pairing between single particle states belonging to different bands, as well as the usual Cooper pairing. It is shown that the interband gap parameter, which is coupled to the usual gap parameter by the Green functions equations of motion, can only contribute indirectly to the tunneling electric current and the thermodynamic potential. In the absence of interband pairing, the equations of motion lead to the usual BCS gap equation. Also, in the absence of interband pairing, the gap parameter is found to be equal to the diagonal matrix element of the superconductor pair potential between electronic Bloch states. An essentially temperature independent anisotropy function which contains all angular dependence of the gap is shown to evolve naturally from this formalism. The overall temperature dependence of the gap is investigated and it is found that with a change of temperature, the magnitude of the gap in different directions changes in the same ration. The ordinary Markowitz-Kadanoff model is shown to be inappropriate for the case of a multi-band superconductor and a generalized version of this model is introduced and discussed. A special case of this model is considered which leads to gap discontinuities at Brillouin zone boundaries

QuTiP 2: A Python framework for the dynamics of open quantum systems

Science.gov (United States)

Johansson, J. R.; Nation, P. D.; Nori, Franco

2013-04-01

We present version 2 of QuTiP, the Quantum Toolbox in Python. Compared to the preceding version [J.R. Johansson, P.D. Nation, F. Nori, Comput. Phys. Commun. 183 (2012) 1760.], we have introduced numerous new features, enhanced performance, and made changes in the Application Programming Interface (API) for improved functionality and consistency within the package, as well as increased compatibility with existing conventions used in other scientific software packages for Python. The most significant new features include efficient solvers for arbitrary time-dependent Hamiltonians and collapse operators, support for the Floquet formalism, and new solvers for Bloch-Redfield and Floquet-Markov master equations. Here we introduce these new features, demonstrate their use, and give a summary of the important backward-incompatible API changes introduced in this version. Catalog identifier: AEMB_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMB_v2_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 No. of lines in distributed program, including test data, etc.: 33625 No. of bytes in distributed program, including test data, etc.: 410064 Distribution format: tar.gz Programming language: Python. Computer: i386, x86-64. Operating system: Linux, Mac OSX. RAM: 2+ Gigabytes Classification: 7. External routines: NumPy, SciPy, Matplotlib, Cython Catalog identifier of previous version: AEMB_v1_0 Journal reference of previous version: Comput. Phys. Comm. 183 (2012) 1760 Does the new version supercede the previous version?: Yes Nature of problem: Dynamics of open quantum systems Solution method: Numerical solutions to Lindblad, Floquet-Markov, and Bloch-Redfield master equations, as well as the Monte Carlo wave function method. Reasons for new version: Compared to the preceding version we have introduced numerous new features, enhanced performance, and made changes in

Interband coherence response to electric fields in crystals: Berry-phase contributions and disorder effects

Science.gov (United States)

Culcer, Dimitrie; Sekine, Akihiko; MacDonald, Allan H.

2017-07-01

In solid state conductors, linear response to a steady electric field is normally dominated by Bloch state occupation number changes that are correlated with group velocity and lead to a steady state current. Recently it has been realized that, for a number of important physical observables, the most important response even in conductors can be electric-field induced coherence between Bloch states in different bands, such as that responsible for screening in dielectrics. Examples include the anomalous and spin-Hall effects, spin torques in magnetic conductors, and the minimum conductivity and chiral anomaly in Weyl and Dirac semimetals. In this paper we present a general quantum kinetic theory of linear response to an electric field which can be applied to solids with arbitrarily complicated band structures and includes the interband coherence response and the Bloch-state repopulation responses on an equal footing. One of the principal aims of our work is to enable extensive transport theory applications using computational packages constructed in terms of maximally localized Wannier functions. To this end we provide a complete correspondence between the Bloch and Wannier formulations of our theory. The formalism is based on density-matrix equations of motion, on a Born approximation treatment of disorder, and on an expansion in scattering rate to leading nontrivial order. Our use of a Born approximation omits some physical effects and represents a compromise between comprehensiveness and practicality. The quasiparticle bands are treated in a completely general manner that allows for arbitrary forms of the spin-orbit interaction and for the broken time reversal symmetry of magnetic conductors. We demonstrate that the interband response in conductors consists primarily of two terms: an intrinsic contribution due to the entire Fermi sea that captures, among other effects, the Berry curvature contribution to wave-packet dynamics, and an anomalous contribution caused

Geometric interpretation of four-wave mixing

DEFF Research Database (Denmark)

Ott, Johan Raunkjær; Steffensen, Henrik; Rottwitt, Karsten

2013-01-01

-like coordinates of the electric fields, which reduce the FWM dynamics to a closed two-dimensional surface, similar to the Bloch sphere of quantum electrodynamics or the Pointcare´ sphere in polarization dynamics. The coordinates are chosen so as to use the gauge invariance symmetries of the FWM equations which...

Depot Medroxyprogesterone Acetate (Depo-Provlera) as a Contrac ...

African Journals Online (AJOL)

Depot Medroxyprogesterone Acetate (Depo-Provlera) as a Contrac·eptive Preparation. Basil Bloch. Abstract. Experience with depot medroxyprogesterone acetate as a contraceptive preparation in 7 335 patients for a total of 38 714 months over a 3-year period is described. The discontinuation rate was 18.3% and the ...

Significance of X-ray imaging techniques in the study of ferro-or ferri-magnets

International Nuclear Information System (INIS)

Miltat, J.

1983-01-01

The subject is discussed under the headings: introduction; basic physics of Bloch wall statics (magnetization (a) parallel (b) perpendicular, to the surface); magnetostrictive strains; detectability of magnetostrictive strains by means of X-ray imaging techniques; interactions of individual lattice defects and moving walls (optical studies; X-ray studies); conclusion. (U.K.)

Les innocents et les coupables; Essai d'exégese

NARCIS (Netherlands)

Gadourek-Backer, Johanna Carina Augusta

1963-01-01

Apres la publication des nouvelles, Camus consacra une grande partie de ses loisirs a la documentation requise pour les Reflexions sur la guillotine. Elles parurent en 1957, avec des contributions d'Arthur Koestler et de M. Bloch, dans un volume intitulé Réflexions sur la peine capitale. Le livre ne

Self-similar solutions of certain coupled integrable systems

CERN Document Server

Chakravarty, S; Kent, S L

2003-01-01

Similarity reductions of the coupled nonlinear Schroedinger equation and an integrable version of the coupled Maxwell-Bloch system are obtained by applying non-translational symmetries. The reduced system of coupled ordinary differential equations are solved in terms of Painleve transcendents, leading to new exact self-similar solutions for these integrable equations.

Self-similar solutions of certain coupled integrable systems

International Nuclear Information System (INIS)

Chakravarty, S; Halburd, R G; Kent, S L

2003-01-01

Similarity reductions of the coupled nonlinear Schroedinger equation and an integrable version of the coupled Maxwell-Bloch system are obtained by applying non-translational symmetries. The reduced system of coupled ordinary differential equations are solved in terms of Painleve transcendents, leading to new exact self-similar solutions for these integrable equations

Neutron scattering studies of low dimensional magnetic systems

DEFF Research Database (Denmark)

Hansen, Ursula Bengård

investigated at low temperaturesand in a longitudinal magnetic eld using neutron spectroscopy. Here we observe thehybridisation of the magnon bound states, inherent to the low dimensional nature ofCoCl2 · 2D2O.At higher temperature, signatures which can be attributed to Magnetic Bloch Oscillationsis observed...

Divergence of dielectric permittivity near phase transition within ferroelectric domain boundaries

Czech Academy of Sciences Publication Activity Database

Márton, Pavel; Stepkova, Vilgelmina; Hlinka, Jiří

2013-01-01

Roč. 86, č. 1 (2013), s. 103-108 ISSN 0141-1594 R&D Projects: GA ČR GAP204/10/0616 Institutional support: RVO:68378271 Keywords : Bloch wall * domain boundary * BaTiO 3 * Ginzburg-Landau-Devonshire theory * permittivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.044, year: 2013

Decoupling Stimulus Duration from Brightness in Metacontrast Masking: Data and Models

Science.gov (United States)

Di Lollo, Vincent; Muhlenen, Adrian von; Enns, James T.; Bridgeman, Bruce

2004-01-01

A brief target that is visible when displayed alone can be rendered invisible by a trailing stimulus (metacontrast masking). It has been difficult to determine the temporal dynamics of masking to date because increments in stimulus duration have been invariably confounded with apparent brightness (Bloch's law). In the research reported here,…

Coulomb drag in multiwall armchair carbon nanotubes

DEFF Research Database (Denmark)

Lunde, A.M.; Jauho, Antti-Pekka

2004-01-01

surface. The cylindrical geometry of the nanotubes and the different parities of the Bloch states are accounted for in the evaluation of the effective Coulomb interaction between charges in the concentric nanotubes. We find a broad peak in rho(21) as a function of temperature at roughly T similar to 0.4T...

A Review of Group Systems Theory

Science.gov (United States)

Connors, Joanie V.; Caple, Richard B.

2005-01-01

The ability to see interpersonal and group processes beyond the individual level is an essential skill for group therapists (Crouch, Bloch & Wanlass, 1994; Dies, 1994; Fuhriman & Burlingame, 1994). In addition to interpersonal therapy models (e.g., Sullivan and Yalom), there are a number of systems theory models that offer a broad array of…

Physical education, sport and recreation: A triad pedagogy of hope ...

African Journals Online (AJOL)

Bloch (2009, 58), a previous advocate of Outcomes-based Education (OBE), states that schooling in SA is a national disaster. Quality holistic education that includes Physical Education (PE) and school sport should be the focal point of progress in developing countries. However, PE is worldwide in a political crisis and the ...

Alien fish species in upper Sakarya River and their distribution ...

African Journals Online (AJOL)

However, the fact that the flood plains have been reclaimed, excessive hunting, destruction of the ecologic balance and invasion of the area by the alien fish species threatens the fish stocks in Sakarya River. In this study, we aimed to determine the dispersion area of Carassius gibelio (Bloch, 1782), Oreochromis niloticus ...

Effective-mass analysis of Bose-Einstein condensates in optical lattices: Stabilization and levitation

International Nuclear Information System (INIS)

Pu, H.; Zhang, W.; Meystre, P.; Baksmaty, L.O.; Bigelow, N.P.

2003-01-01

We investigate the time evolution of a Bose-Einstein condensate in a periodic optical potential. Using an effective mass formalism, we study the equation of motion for the envelope function modulating the Bloch states of the lattice potential. In particular, we show how the negative effective-mass affects the dynamics of the condensate

Homer: A Collection of Critical Essays. Twentieth Century Views Series.

Science.gov (United States)

Steiner, George, Ed.; Fagles, Robert, Ed.

One of a series of works aimed at presenting contemporary critical opinion on major authors, this collection includes essays by George Steiner, Leo Tolstoy, Ezra Pound, Erich Auerbach, Edwin Muir, Cedric H. Whitman, Albert B. Lord, W. H. Auden, Ernst Bloch, Georg Lukacs, C. Day Lewis, Gabriel Germain, Franz Kafka, Rachel Bespaloff, Robert…

Analysis of thin-film photonic crystal microstructures

International Nuclear Information System (INIS)

Pottage, John Mark

2003-01-01

Optical-scale microstructures containing thin-film photonic crystals (TFPCs) are modelled by transfer/scattering matrix methods, based on Fourier-series expansion of the optical Bloch eigenmodes. The majority of the TFPCs considered consist of 2D arrays of holes arranged in a triangular lattice, etched into high-index Al x Ga 1-x As and placed on a low-index oxidised substrate. These TFPCs can be easily fabricated by standard electron-beam lithography techniques. Unlike most photonic crystal devices that have been proposed, our 'intra-pass-band' TFPCs would work by exploiting the somewhat surprising properties of propagating optical Bloch waves rather than directly relying on photonic bandgaps. By numerical modelling, it is demonstrated that 2D-patterned TFPCs can support highly dispersive high-Q quasi-guided and truly-guided resonant modes, and the unusual properties of these modes are explained in terms of their Bloch-wave compositions. Modal dispersion diagrams of TFPCs, showing the loci of the resonant modes in in-plane wavevector space at fixed frequency, are calculated. These so-called 'resonance diagrams' and variants thereof, are shown to be a useful design tool for TFPC-based integrated optical components. It is suggested that TFPCs may be a viable alternative to distributed Bragg reflectors in semiconductor vertical cavity surface-emitting lasers, possessing potential advantages in terms of compactness and ease of fabrication. The high angular and spectral dispersion of the resonant modes implies that TFPCs could form the basis of a new family of compact devices for performing such functions as wavelength-division multiplexing/demultiplexing, beam-steering and frequency-selective filtering. Enhancement of nonlinear effects could also be achieved in TFPC resonators, because in them a high cavity Q-factor and a low in-plane group-velocity can be attained simultaneously. (author)

Atomic interferometers in an optical lattice

International Nuclear Information System (INIS)

Pelle, Bruno

2013-01-01

The aim of the ForCa-G project, for Casimir force and short range Gravitation, lies into the measurement of short range forces between atoms and a mirror using atomic interferometry techniques. Particularly, the Casimir-Polder force and the pursuit of short range gravitational tests in the frame of potential deviations of Newton's law are aimed. This experiment is based on the trapping of neutral atoms in a 1D vertical optical lattice, where the energy eigenvalues of the Hamiltonian describing this system is the so-called Wannier-Stark ladder of discrete energy states localized in each lattice well. This work constitutes a demonstration of principle of this project with atoms set far from the mirror. Each energy state is thus separated from the one of the adjacent well by the potential energy increment between those two wells, called the Bloch frequency ν B . Then, atomic interferometers are realized in the lattice using Raman or microwave pulses where the trapped atomic wave functions are placed, and then recombined, in a superposition of states between different energy states localized either in the same well, either in adjacent wells. This work presents the study of different kinds of atomic interferometers in this optical lattice, characterized in terms of sensibility and systematic effects on the Bloch frequency measurement. One of the studied interferometers accessed to a sensitivity on the Bloch frequency of σ δ ν B /ν B =9.0x10 -6 at 1∼s in relative, which integrates until σ δ ν B /ν B =1. 10 -7 in 2800∼s. This corresponds to a state-of-the-art measurement of the gravity acceleration g for a trapped atomic gravimeter. (author)

On the "Critique of Everyday Life" to "Metaphilosophy": Henri Lefebvre's Philosophical-Political Legacy of the Cultural Revolution

Science.gov (United States)

Sünker, Heinz

2014-01-01

Henri Lefebvre (1901-91), philosopher and sociologist, is, together with Theodor W. Adorno, Max Horkheimer, Walter Benjamin and Ernst Bloch, one of the most relevant representatives of the first generation in Western Marxism. His engagement with Marxism led him to analyse everyday life in post-war France in order to decipher the possibilities of,…

Theory of the nuclear self-oscillator used to measure the earth's magnetic field; Theorie de l'auto-oscillateur nucleaire utilise pour la mesure du champ magnetique terrestre

Energy Technology Data Exchange (ETDEWEB)

Solomon, Ionel

1961-07-01

After an energy assessment of the device, this note reports the development of theoretical formulations describing its operation. The author uses Bloch equations, addresses the rotating field produced by nuclear magnetisation, and discusses a steady solution. The next part discusses the field measurement precision, notably while assessing various noises. The sample is then presented.

Balts show strong notes in Grammy Awards

Index Scriptorium Estoniae

2005-01-01

Los Angeleses 8. veebr. Grammy Awards nominantide seas läti laulja Elina Garanca, dirigendid Paavo Järvi (Schumann "Cello Concerto" and Bloch's "Schelomo") ja Maris Jansons. Eelmisel aastal pälvis Grammy teos Sibelius "Cantatas" (esitajad Ellerheina tütarlastekoor Ester Loitme juhatusel, Eesti Rahvusmeeskoor, ERSO, dirigendid Ants Soots ja Paavo Järvi)

Schrödinger operators on a periodically broken zigzag carbon ...

Indian Academy of Sciences (India)

In this paper, we study the spectra of Schrödinger operators on zigzag carbon nanotubes, which are broken by abrasion or during refining process. Throughout this paper, we assume that the carbon nanotubes are broken periodically and we deal with one of those models. Making use of the Floquet–Bloch theory, we ...

Infrared problem in non-Abelian gauge theory

International Nuclear Information System (INIS)

Yao, Y.

1976-01-01

I extend the Bloch--Nordsieck idea to show that in the lowest nontrivial order of radiative correction the fermion--fermion and gauge-meson--fermion scattering rates are finite, provided that they are averaged over the initial and summed over the final internal spin states. Questions of the physical gauge coupling and infrared slavery are discussed

Computational Modeling of Ultrafast Pulse Propagation in Nonlinear Optical Materials

Science.gov (United States)

Goorjian, Peter M.; Agrawal, Govind P.; Kwak, Dochan (Technical Monitor)

1996-01-01

There is an emerging technology of photonic (or optoelectronic) integrated circuits (PICs or OEICs). In PICs, optical and electronic components are grown together on the same chip. rib build such devices and subsystems, one needs to model the entire chip. Accurate computer modeling of electromagnetic wave propagation in semiconductors is necessary for the successful development of PICs. More specifically, these computer codes would enable the modeling of such devices, including their subsystems, such as semiconductor lasers and semiconductor amplifiers in which there is femtosecond pulse propagation. Here, the computer simulations are made by solving the full vector, nonlinear, Maxwell's equations, coupled with the semiconductor Bloch equations, without any approximations. The carrier is retained in the description of the optical pulse, (i.e. the envelope approximation is not made in the Maxwell's equations), and the rotating wave approximation is not made in the Bloch equations. These coupled equations are solved to simulate the propagation of femtosecond optical pulses in semiconductor materials. The simulations describe the dynamics of the optical pulses, as well as the interband and intraband.

Modeling the diffusion magnetic resonance imaging signal inside neurons

International Nuclear Information System (INIS)

Nguyen, D V; Li, J R; Grebenkov, D S; Le Bihan, D

2014-01-01

The Bloch-Torrey partial differential equation (PDE) describes the complex transverse water proton magnetization due to diffusion-encoding magnetic field gradient pulses. The integral of the solution of this PDE yields the diffusion magnetic resonance imaging (dMRI) signal. In a complex medium such as cerebral tissue, it is difficult to explicitly link the dMRI signal to biological parameters such as the cellular geometry or the cellular volume fraction. Studying the dMRI signal arising from a single neuron can provide insight into how the geometrical structure of neurons influences the measured signal. We formulate the Bloch-Torrey PDE inside a single neuron, under no water exchange condition with the extracellular space, and show how to reduce the 3D simulation in the full neuron to a 3D simulation around the soma and 1D simulations in the neurites. We show that this latter approach is computationally much faster than full 3D simulation and still gives accurate results over a wide range of diffusion times

GOVERNING BOARD OF THE PENSION FUND

CERN Multimedia

2004-01-01

The Governing Board held its 120th and 121st meetings on 4 November and 2 December 2003 respectively. At the first of these two meetings, the Board first continued its examination of ESO's requests. In connection to this, the Board heard a presentation of the requests by M. Bloch, ESO's Head of Personnel, including a proposal that ESO's contributions and benefits to its beneficiaries be paid in euros. This option had previously been examined by the Working Group on ESO's Requests which had submitted a negative opinion to the Governing Board. Mr Bloch informed the Board that ESO was suspending that request and therefore invited the Governing Board to concentrate on the other options. After some discussion, the Governing Board decided that the euro-based request should be deemed withdrawn and that the Working Group would resume its examination of the other options put forward by ESO at the beginning of the year. At the same meeting, J.-P. Matheys reported on the recent meeting of the Working Group on Actuarial...

Monogeneans of leatherjackets, Oligoplites spp. (Osteichthyes: Carangidae, with the description of a new species of Metacamopia (Monogenea: Allodiscocotylidae from the coast of the State of Rio de Janeiro, Brazil

Directory of Open Access Journals (Sweden)

Ricardo M Takemoto

1996-04-01

Full Text Available Metacamopia oligoplites n. sp., a gill filament parasite of carangid fishes of three species of Oligoplites Gill, O. palometa (Cuvier, O. saurus (Bloch & Schneider, and O. saliens (Bloch, from the coast of the State of Rio de Janeiro, Brazil, is described and illustrated. Metacamopia oligoplites n. sp. differs from M. indica by: the shape of the body; the pre-, para-, and post-germarial testes; vaginas lacking sclerotized structures; well-developed seminal receptacles; muscular sleeves around the constriction between the vaginas and the seminal receptacles; and the haptor highly asymmetric, with a large, heel-like area; and differs from M. chorinemi by: the esophagus lacking diverticles; a larger number of testes (26-55 and not just, approximately 10; and the vaginas lacking sclerotized structures of any kind. This is the first record of Metacamopia in the South Atlantic Ocean. The generic diagnosis of Metacamopia is emended. Hargicola oligoplites is reported for the first time in the South Atlantic Ocean. Oligoplites palometa and O. saliens are new host records for Hargicola oligoplites.

Transients of the electromagnetically-induced-transparency-enhanced refractive Kerr nonlinearity: Theory

International Nuclear Information System (INIS)

Pack, M. V.; Camacho, R. M.; Howell, J. C.

2006-01-01

We present a theory describing the transients and rise times of the refractive Kerr nonlinearity which is enhanced using electromagnetically induced transparency (EIT). We restrict our analysis to the case of a pulsed signal field with continuous-wave EIT fields, and all fields are well below saturation. These restrictions enable the reduction of an EIT Kerr, four-level, density-matrix equation to a two-level Bloch-vector equation which has a simple and physically intuitive algebraic solution. The physically intuitive picture of a two-level Bloch vector provides insights that are easily generalized to more complex and experimentally realistic models. We consider generalization to the cases of Doppler broadening, many-level EIT systems (we consider the D1 line of 87 Rb), and optically thick media. For the case of optically thick media we find that the rise time of the refractive EIT Kerr effect is proportional to the optical thickness. The rise time of the refractive EIT Kerr effect sets important limitations for potential few-photon applications

Accurate donor electron wave functions from a multivalley effective mass theory.

Science.gov (United States)

Pendo, Luke; Hu, Xuedong

Multivalley effective mass (MEM) theories combine physical intuition with a marginal need for computational resources, but they tend to be insensitive to variations in the wavefunction. However, recent papers suggest full Bloch functions and suitable central cell donor potential corrections are essential to replicating qualitative and quantitative features of the wavefunction. In this talk, we consider a variational MEM method that can accurately predict both spectrum and wavefunction of isolated phosphorus donors. As per Gamble et. al, we employ a truncated series representation of the Bloch function with a tetrahedrally symmetric central cell correction. We use a dynamic dielectric constant, a feature commonly seen in tight-binding methods. Uniquely, we use a freely extensible basis of either all Slater- or all Gaussian-type functions. With a large basis able to capture the influence of higher energy eigenstates, this method is well positioned to consider the influence of external perturbations, such as electric field or applied strain, on the charge density. This work is supported by the US Army Research Office (W911NF1210609).

Photonic quantum simulator for unbiased phase covariant cloning

Science.gov (United States)

Knoll, Laura T.; López Grande, Ignacio H.; Larotonda, Miguel A.

2018-01-01

We present the results of a linear optics photonic implementation of a quantum circuit that simulates a phase covariant cloner, using two different degrees of freedom of a single photon. We experimentally simulate the action of two mirrored 1→ 2 cloners, each of them biasing the cloned states into opposite regions of the Bloch sphere. We show that by applying a random sequence of these two cloners, an eavesdropper can mitigate the amount of noise added to the original input state and therefore, prepare clones with no bias, but with the same individual fidelity, masking its presence in a quantum key distribution protocol. Input polarization qubit states are cloned into path qubit states of the same photon, which is identified as a potential eavesdropper in a quantum key distribution protocol. The device has the flexibility to produce mirrored versions that optimally clone states on either the northern or southern hemispheres of the Bloch sphere, as well as to simulate optimal and non-optimal cloning machines by tuning the asymmetry on each of the cloning machines.

Magnetic and structural properties of ZNn-doped YIG nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Garcia, R.P.; Del Toro, A.D.; Davila, Y.G.; Gomes, J.L.; Goncalves, L.P.; Hernandez, E.P. [Universidade Federal de Pernambuco (UFPE), PR (Brazil)

2016-07-01

Full text: Zn-doped YIG was prepared using the sol gel method and TGA measurements showed the phase formation between 900°C and 1000°C. XRD analysis showed close to 1100°C the formation of Franklinite phase, coexisting with the cubic YIG. Y3(Fe1-xZnx)5O12 samples with different Zn concentrations (x = 0, 0.01, 0.03 and 0.05) were prepared and analyzed by a magnetic study. A decrease in magnetic moment of the samples was confirmed with increasing the concentration of Zn ions. The diminishing is due to the substitution of Fe ions by Zn. This also confirmed the results of XRD showing the linear increasing in the lattice parameter. Fittings by the Bloch's law shows results compared with those already reported in the literature. Both the exponent of how Bloch constant presented similar values to those reported in YIG doped with other ions. We obtained the parameter α ∼ 10-6 K-n and n close to 1.9 for all samples. (author)

Field driven magnetic racetrack memory accompanied with the interfacial Dzyaloshinskii-Moriya interaction

Science.gov (United States)

Kim, June-Seo; Lee, Hyeon-Jun; Hong, Jung-Il; You, Chun-Yeol

2018-06-01

The in-plane magnetic field pulse driven domain wall motion on a perpendicularly magnetized nanowire is numerically investigated by performing micromagnetic simulations and magnetic domain wall dynamics are evaluated analytically with one-dimensional collective coordinate models including the interfacial Dzyaloshinskii-Moriya interaction. With the action of the precession torque, the chirality and the magnetic field direction dependent displacements of the magnetic domain walls are clearly observed. In order to move Bloch type and Neel type domain walls, a longitudinal and a transverse in-plane magnetic field pulse are required, respectively. The domain wall type (Bloch or Neel) can easily be determined by the dynamic motion of the domain walls under the applied pulse fields. By applying a temporally asymmetric in-plane field pulse and successive notches in the perpendicularly magnetized nanowire strip line with a proper interval, the concept of racetrack memory based on the synchronous displacements of the chirality dependent multiple domain walls is verified to be feasible. Requirement of multiple domain walls with homogeneous chirality is achieved with the help of Dzyaloshinskii-Moriya interaction.

( ucleus rofeno (Bloch s assay ofos to ) using y

African Journals Online (AJOL)

SAM

eus assay. T. s a useful to and can be y, profenofos, chemicals o ural farming aterbodies. Th onment has b ... ty of p tatus ( ucleus. N. S. Nagp ational Bureau. U.P., India. ent of Zoology .... and may b ni et al. 2006) ond to toxic an allow the y hazardous. NA per cell, t d the low m .... Saleh KA, Alshehri MA (2011). The intensity ...

Bloch walls and the non-ideal bose gas spectrum

International Nuclear Information System (INIS)

Vitiello, S.A.S.

1986-05-01

The quasi-particle spectrum of non-ideal Bose gas with domain walls in the condensate is investigated. The existence of such a system is determined from solutions of Gross-Pitaevskii equation which represent many-soliton systems. The walls which make the condensate non-uniform are responsible for density and velocity fields ρ(x) and υ(x) repectively. In the laboratory, the Bogoliubov spectrum, supposed to be true for an uniform condensate at rest, is changed due to the velocity field to which the quasi-particles are submited. The spectrum in the laboratory frame is obtained by considering the Galileu invariance principle and the interaction energy between the quasi-particle and its medium. The importance in considering the last two facts is illustrated by the analyse of a constant density condensate which moves uniformly in the laboratory. The many-soliton spectrum configuration and structure function are studied by the Monte Carlo method. In an approximation that assumes the quasi-particle to be point like, the condensate can be treated as locally uniform. For each event the position x of a quasi-particle and its momentum in a frame with velocity υ(x) are determined. Thus, by a convenient Galileu transformation the energy spectrum in the laboratory an be obtained. The results show a phonon spectrum which splits in two branches in the high momenta region. In this region the lower energy branch exibiths a point of minimum. Analogies with the He II are explored. (author) [pt

Errata Resonance, Vol.20, No.12, 2015. Rajaram Nityananda, Sun ...

Indian Academy of Sciences (India)

IAS Admin

Resonance, Vol.20, No.12, 2015. Rajaram Nityananda, Sun, Sky and Clouds: Where Light and Matter Meet. Page 1121: The correct Figure 5 is reproduced below: Resonance, Vol.20, No.11, 2015. Anil Kumar, Felix Bloch (1905–1983). Page 956: Para 1, Line 5, 'also from Zürich' should be read as 'from nearby Bern'.

Magnetic phenomena in F.F.A.G. cyclotrons

International Nuclear Information System (INIS)

Beurtey, R.

1957-01-01

This study regroups and develops some experimental and theoretical results obtained with spiral tract cyclotrons. The method used has been studied previously by C. BLOCH, whom we thank for his helpful advice. We have tried to give the main useful results, which are also in accordance with the rather scarce experimental results obtained on spiral pole pieces. (author) [fr

Optical bistability without the rotating wave approximation

Energy Technology Data Exchange (ETDEWEB)

Sharaby, Yasser A., E-mail: Yasser_Sharaby@hotmail.co [Physics Department, Faculty of Applied Sciences, Suez Canal University, Suez (Egypt); Joshi, Amitabh, E-mail: ajoshi@eiu.ed [Department of Physics, Eastern Illinois University, Charleston, IL 61920 (United States); Hassan, Shoukry S., E-mail: Shoukryhassan@hotmail.co [Mathematics Department, College of Science, University of Bahrain, P.O. Box 32038 (Bahrain)

2010-04-26

Optical bistability for two-level atomic system in a ring cavity is investigated outside the rotating wave approximation (RWA) using non-autonomous Maxwell-Bloch equations with Fourier decomposition up to first harmonic. The first harmonic output field component exhibits reversed or closed loop bistability simultaneously with the usual (anti-clockwise) bistability in the fundamental field component.

Optical bistability without the rotating wave approximation

International Nuclear Information System (INIS)

Sharaby, Yasser A.; Joshi, Amitabh; Hassan, Shoukry S.

2010-01-01

Optical bistability for two-level atomic system in a ring cavity is investigated outside the rotating wave approximation (RWA) using non-autonomous Maxwell-Bloch equations with Fourier decomposition up to first harmonic. The first harmonic output field component exhibits reversed or closed loop bistability simultaneously with the usual (anti-clockwise) bistability in the fundamental field component.

Estructura de la comunidad de peces en el sistema Candelaria-Panlau, Campeche, México

Directory of Open Access Journals (Sweden)

Luis Amado Ayala-Pérez

1998-09-01

Full Text Available Se describe el comportamiento de los parámetros de temperatura, salinidad, transparencia del agua y temperatura ambiente, y de la abundancia y diversidad de la comunidad del peces del sistema Candelaria-Panlau en escalas temporal y espacial. Los trabajos de campo se realizaron de manera mensual en cinco estaciones entre abril de 1993 y abril de 1994. La comunidad de peces quedó representada por 50 especies con 7 926 organismos y 144.7 kg de peso. Los valores de abundancia y diversidad de la comunidad fueron: 0.09 ind/m², 1.61 g/m² 18.25 g/ind, H’n = 1.879, J = 0.475 y D = 5.681. Las especies con dominio ecológico fueron: Cathorops melanopus, Diapterus rhombeus, Anchoa mitchilli, Sphoeroides testudineus, Bairdiella chrysura, B. ronchus, Cynoscion arenarius, y C. nebulosus, que en conjunto representan el 90.9 % en número y el 78.9 % en peso de la captura total. Las matrices de valores de los parámetros ambientales y de abundancia numérica de la comunidad de peces, fueron sometidas a un análisis de factores con el método de extracción de componentes principales, su representación gráfica confirma la definición de especies dominantes y demuestra que la salinidad, estación cinco y mes de febrero son los componentes que caracterizan al sistema y a la comunidad de peces.The environmental and ecological patterns of the fish community in Candelaria-Panlau system (Mexico are described. Parameters of the water temperature, salinity and transparency, and density, biomass and diversity of the fish community were analyzed. Between April 1993 and April 1994 five stations were sampled monthly. The fish community had 50 species (7 926 individuals, 144.7 kg of weight. The abundance and diversity values for the fish community were: 0.09 ind/m² ; 1.61 g/m²; 18.25 g/ind ; H'n = 1.879; J = 0.475 and D = 5.681. The species with ecological dominance were: Cathorops melanopus, Diapterus rhombeus, Anchoa mitchilli, Sphoeroides testudineus, Bairdiella

Stopping powers of Zr, Pd, Cd, In and Pb for 6.5 MeV protons and mean excitation energies

International Nuclear Information System (INIS)

Ishiwari, R.; Shiomi, N.; Sakamoto, N.

1983-01-01

Stopping powers of Zr, Pd, Cd, In and Pb have been measured for 6.5 MeV protons. Mean excitation energies have been extracted from the stopping power data by taking into account Bloch correction and Z 1 3 correction. For the shell correction the Bonderup shell correction has been used. The results agree fairly well with those of other authors

Ultrastructure of the spermatozoon of the diphyllobothriidean cestode Cephalochlamys namaquensis (Cohn, 1906)

Czech Academy of Sciences Publication Activity Database

Bruňanská, M.; Matey, V.; Nebesářová, Jana

2012-01-01

Roč. 111, č. 3 (2012), s. 1037-1043 ISSN 0932-0113 Institutional support: RVO:60077344 Keywords : GLARIDACRIS-CATOSTOMI COOPER * WENYONIA-VIRILIS WOODLAND * SPERMATOLOGICAL CHARACTERS * MATURE SPERMATOZOON * ALAPTERURUS-ELECTRICUS * SPERM ULTRASTRUCTURE * CRASSUM BLOCH * SPERMIOGENESIS * PARASITE * SPERMATOGENESIS Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.852, year: 2012 http://link.springer.com/article/10.1007%2Fs00436-012-2928-4

Selection of planes in nuclear magnetic resonance tomography

International Nuclear Information System (INIS)

Bonagamba, T.J.

1986-01-01

A prototype aiming to obtain images in nuclear magnetic resonance tomography was developed, by adjusting NMR spectrometer in the IFQSC Laboratory. The techniques for selecting planes were analysed by a set of computer codes, which were elaborated from Bloch equation solutions to simulate the spin system behaviour. Images were obtained using planes with thickness inferior to 1 cm. (M.C.K.)

Work notice

CERN Multimedia

TS-FM

2005-01-01

Please note that work to repair the water mains on Route Bloch near Gate C will be carried out between 12 and 30 September 2005. The area between Route Bakker and Gate C will be closed to traffic during this period. You are kindly requested to comply with the road signs in place. Thank you for your understanding. TS-FM Group

A rigorous proof of the Landau-Peierls formula and much more

DEFF Research Database (Denmark)

Briet, Philippe; Cornean, Horia; Savoie, Baptiste

2012-01-01

We present a rigorous mathematical treatment of the zero-field orbital magnetic susceptibility of a non-interacting Bloch electron gas, at fixed temperature and density, for both metals and semiconductors/insulators. In particular, we obtain the Landau-Peierls formula in the low temperature and d...... and density limit as conjectured by Kjeldaas and Kohn (Phys Rev 105:806–813, 1957)....

Excitation transfer in two two-level systems coupled to an oscillator

International Nuclear Information System (INIS)

Hagelstein, P L; Chaudhary, I U

2008-01-01

We consider a generalization of the spin-boson model in which two different two-level systems are coupled to an oscillator, under conditions where the oscillator energy is much less than the two-level system energies, and where the oscillator is highly excited. We find that the two-level system transition energy is shifted, producing a Bloch-Siegert shift in each two-level system similar to what would be obtained if the other were absent. At resonances associated with energy exchange between a two-level system and the oscillator, the level splitting is about the same as would be obtained in the spin-boson model at a Bloch-Siegert resonance. However, there occur resonances associated with the transfer of excitation between one two-level system and the other, an effect not present in the spin-boson model. We use a unitary transformation leading to a rotated system in which terms responsible for the shift and splittings can be identified. The level splittings at the anticrossings associated with both energy exchange and excitation transfer resonances are accounted for with simple two-state models and degenerate perturbation theory using operators that appear in the rotated Hamiltonian

Zak phase and band inversion in dimerized one-dimensional locally resonant metamaterials

Science.gov (United States)

Zhu, Weiwei; Ding, Ya-qiong; Ren, Jie; Sun, Yong; Li, Yunhui; Jiang, Haitao; Chen, Hong

2018-05-01

The Zak phase, which refers to Berry's phase picked up by a particle moving across the Brillouin zone, characterizes the topological properties of Bloch bands in a one-dimensional periodic system. Here the Zak phase in dimerized one-dimensional locally resonant metamaterials is investigated. It is found that there are some singular points in the bulk band across which the Bloch states contribute π to the Zak phase, whereas in the rest of the band the contribution is nearly zero. These singular points associated with zero reflection are caused by two different mechanisms: the dimerization-independent antiresonance of each branch and the dimerization-dependent destructive interference in multiple backscattering. The structure undergoes a topological phase-transition point in the band structure where the band inverts, and the Zak phase, which is determined by the numbers of singular points in the bulk band, changes following a shift in dimerization parameter. Finally, the interface state between two dimerized metamaterial structures with different topological properties in the first band gap is demonstrated experimentally. The quasi-one-dimensional configuration of the system allows one to explore topology-inspired new methods and applications on the subwavelength scale.

Geometric description of modular and weak values in discrete quantum systems using the Majorana representation

Science.gov (United States)

Cormann, Mirko; Caudano, Yves

2017-07-01

We express modular and weak values of observables of three- and higher-level quantum systems in their polar form. The Majorana representation of N-level systems in terms of symmetric states of N  -  1 qubits provides us with a description on the Bloch sphere. With this geometric approach, we find that modular and weak values of observables of N-level quantum systems can be factored in N  -  1 contributions. Their modulus is determined by the product of N  -  1 ratios involving projection probabilities between qubits, while their argument is deduced from a sum of N  -  1 solid angles on the Bloch sphere. These theoretical results allow us to study the geometric origin of the quantum phase discontinuity around singularities of weak values in three-level systems. We also analyze the three-box paradox (Aharonov and Vaidman 1991 J. Phys. A: Math. Gen. 24 2315-28) from the point of view of a bipartite quantum system. In the Majorana representation of this paradox, an observer comes to opposite conclusions about the entanglement state of the particles that were successfully pre- and postselected.

Contribution to the study of nuclear resonance in magnetic media (1963); Contribution a l'etude de la resonance nucleaire dans les milieux magnetique (1963)

Energy Technology Data Exchange (ETDEWEB)

Hartmann-Boutron, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-06-15

An attempt is made to interpret the results of nuclear magnetic resonance experiments made by various workers on ferro and ferrimagnetic compounds of the iron group. The problems encountered are the following: effects of the dipolar fields and the hyperfine structure anisotropy; signal intensity; frequency pulling due to the Suhl-Nakamura interaction between nuclear spins ; nuclear relaxation and ferrimagnetic resonance in single domain samples of impure YIG; nuclear relaxation in the Bloch walls of insulators. The results of our calculations are generally in good agreement with experiment. (author) [French] On se propose d'interpreter les resultats d'experiences de resonance magnetique nucleaire fates par divers auteurs sur des composes ferro et ferrimagnetiques du groupe du fer. Les problemes abordes sont les suivants: effets des champs dipolaires et de l'anisotropie de structure hyperfine; intensite des signaux; deplacement de frequence du a l'interaction de Suhl-Nakamura entre spins nucleaires; relaxation nucleaire et resonance ferrimagnetique dans les echantillons monodomaines de grenat de fer et d'yttrium impur; relaxation nucleaire dans les parois de Bloch des isolants. Les resultats des calculs sont generalement en bon accord avec l'experience. (auteur)

Magnetic hysteresis scaling in thulium: Implication of irreversibility-related scaling for soliton wall motion in an Ising system

International Nuclear Information System (INIS)

Kobayashi, Satoru

2013-01-01

We report low-field magnetic hysteresis scaling in thulium with strong uniaxial anisotropy. A power-law hysteresis scaling with an exponent of 1.13±0.02 is found between hysteresis loss and remanent flux density of minor loops in the low-temperature ferrimagnetic phase. This exponent value is slightly lower than 1.25–1.4 observed previously for ferromagnets and helimagnets. Unlike spiral and/or Bloch walls with a finite transition width, typical for Dy, Tb, and Ho with planar anisotropy, a soliton wall with a sudden phase shift between neighboring domains may dominate in Tm due to its Ising-like character. The observations imply the presence of universality class of hysteresis scaling that depends on the type of magnetic anisotropy. - Highlights: ► We observe magnetic hysteresis scaling in thulium with a power law exponent of 1.13. ► Irreversibility of soliton walls dominates owing to its strong uniaxial anisotropy. ► The exponent is lower than those for Bloch wall and spiral wall. ► The results imply the presence of universality class that depends on the wall type.

Some models of spin coherence and decoherence in storage rings

International Nuclear Information System (INIS)

Heinemann, K.

1997-09-01

I present some simple exactly solvable models of spin diffusion caused by synchrotron radiation noise in storage rings. I am able to use standard stochastic differential equation and Fokker-Planck methods and I thereby introduce, and exploit, the polarization density. This quantity obeys a linear evolution equation of the Bloch type, which is, like the Fokker-Planck equation, universal in the sense that it is independent of the state of the system. I also briefly consider Bloch equations for other local polarization quantities derived from the polarization density. One of the models chosen is of relevance for some existing and proposed low energy electron (positron) storage rings which need polarization. I present numerical results for a ring with parameters typical of HERA and show that, where applicable, the results of my approach are in satisfactory agreement with calculations using SLIM. These calculations provide a numerical check of a basic tenet of the conventional method of calculating depolarization using the n-vector-axis. I also investigate the equilibrium behaviour of the spin ensemble when there is no synchrotron radiation. Finally, I summarize other results which I have obtained using the polarization density and which will be published separately. (orig.)

Magnetic and structural properties of Zn-doped yttrium iron garnet nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pena-Garcia, R.; Delgado, A.; Guerra, Y.; Farias, B.V.M.; Martinez, D. [Pos Graduacao em Ciencia de Materiais, Universidade Federal de Pernambuco, Recife, PE (Brazil); Skovroinski, E. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Recife, PE (Brazil); Galembeck, A. [Pos Graduacao em Ciencia de Materiais, Universidade Federal de Pernambuco, Recife, PE (Brazil); Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Recife, PE (Brazil); Padron-Hernandez, E. [Pos Graduacao em Ciencia de Materiais, Universidade Federal de Pernambuco, Recife, PE (Brazil); Departamento de Fisica, Universidade Federal de Pernambuco, Recife, PE (Brazil)

2016-09-15

Zn-doped YIG was prepared using the sol-gel method with TGA measurements showing the phase formation between 900 and 1000 C. XRD analysis showed close to 1100 C the formation of Franklinite phase, coexisting with the cubic YIG. Y{sub 3}(Fe{sub 1-x}Zn{sub x}){sub 5}O{sub 12} samples with different Zn concentrations (x = 0, 0.01, 0.03, and 0.05) were prepared and analyzed for a magnetic study. A decrease in magnetic moment of the samples was confirmed on increasing the concentration of Zn ions. This decrease is due to the substitution of Fe ions by Zn. This also confirmed the results of XRD showing the linear increase in the lattice parameter. Fittings by Bloch's law shows results compared with those already reported in the literature. The exponent and constant for the Bloch law presented similar values to those reported for YIG doped with other ions. We obtained the parameter α ∝10{sup -6} K{sup -n} with n close to 1.9 for all samples. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Einstein-Podolsky-Rosen steering: Its geometric quantification and witness

Science.gov (United States)

Ku, Huan-Yu; Chen, Shin-Liang; Budroni, Costantino; Miranowicz, Adam; Chen, Yueh-Nan; Nori, Franco

2018-02-01

We propose a measure of quantum steerability, namely, a convex steering monotone, based on the trace distance between a given assemblage and its corresponding closest assemblage admitting a local-hidden-state (LHS) model. We provide methods to estimate such a quantity, via lower and upper bounds, based on semidefinite programming. One of these upper bounds has a clear geometrical interpretation as a linear function of rescaled Euclidean distances in the Bloch sphere between the normalized quantum states of (i) a given assemblage and (ii) an LHS assemblage. For a qubit-qubit quantum state, these ideas also allow us to visualize various steerability properties of the state in the Bloch sphere via the so-called LHS surface. In particular, some steerability properties can be obtained by comparing such an LHS surface with a corresponding quantum steering ellipsoid. Thus, we propose a witness of steerability corresponding to the difference of the volumes enclosed by these two surfaces. This witness (which reveals the steerability of a quantum state) enables one to find an optimal measurement basis, which can then be used to determine the proposed steering monotone (which describes the steerability of an assemblage) optimized over all mutually unbiased bases.

A imaginação histórica da sociologia The historical imagination of sociology

Directory of Open Access Journals (Sweden)

Theda Skocpol

2007-05-01

Full Text Available O texto aborda o início e os desdobramentos da tradição da sociologia histórica durante o século XX. Parte da análise do eclipse parcial dos estudos históricos durante o período de hegemonia do funcionalismo e das teorias da modernização para depois empreender uma síntese do processo de resgate da tradição histórica a partir da obra de nove estudiosos: Marc Bloch, Perry Anderson, E. P. Thompson, Barrington Moore, Karl Polanyi, Immanuel Wallerstein, Reinhard Bendix, Charles Tilly e S. N. Eisenstadt. Palavras-chave: Sociologia. História. Funcionalismo. Imaginação. The text deals with the beginnings and the development of sociology historical tradition. It starts with an analysis of the partial eclipse of historical studies during the hegemony of functionalism and modernization theories, but its central subject is the re-emergence of the historical tradition in the works of nine scholars: Marc Bloch, Perry Anderson, E. P. Thompson, Barrington Moore, Karl Polanyi, Immanuel Wallerstein, Reinhard Bendix, Charles Tilly e S. N. Eisenstadt. Keywords: Sociology; History; Functionalism; Imagination.

Contribution to the study of nuclear resonance in magnetic media (1963); Contribution a l'etude de la resonance nucleaire dans les milieux magnetique (1963)

Energy Technology Data Exchange (ETDEWEB)

Hartmann-Boutron, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-06-15

An attempt is made to interpret the results of nuclear magnetic resonance experiments made by various workers on ferro and ferrimagnetic compounds of the iron group. The problems encountered are the following: effects of the dipolar fields and the hyperfine structure anisotropy; signal intensity; frequency pulling due to the Suhl-Nakamura interaction between nuclear spins ; nuclear relaxation and ferrimagnetic resonance in single domain samples of impure YIG; nuclear relaxation in the Bloch walls of insulators. The results of our calculations are generally in good agreement with experiment. (author) [French] On se propose d'interpreter les resultats d'experiences de resonance magnetique nucleaire fates par divers auteurs sur des composes ferro et ferrimagnetiques du groupe du fer. Les problemes abordes sont les suivants: effets des champs dipolaires et de l'anisotropie de structure hyperfine; intensite des signaux; deplacement de frequence du a l'interaction de Suhl-Nakamura entre spins nucleaires; relaxation nucleaire et resonance ferrimagnetique dans les echantillons monodomaines de grenat de fer et d'yttrium impur; relaxation nucleaire dans les parois de Bloch des isolants. Les resultats des calculs sont generalement en bon accord avec l'experience. (auteur)

Dynamical electrical conductivity of graphene.

Science.gov (United States)

Rani, Luxmi; Singh, Navinder

2017-06-28

For graphene (a Dirac material) it has been theoretically predicted and experimentally observed that DC resistivity is proportional to T 4 when the temperature is much less than Bloch-Grüneisen temperature ([Formula: see text]) and T-linear in the opposite case ([Formula: see text]). Going beyond this case, we investigate the dynamical electrical conductivity in graphene using the powerful method of the memory function formalism. In the zero frequency regime, we obtain the above mentioned behavior which was previously obtained using the Bloch-Boltzmann kinetic equation. In the finite frequency regime, we obtain several new results: (1) the generalized Drude scattering rate, in the zero temperature limit, shows [Formula: see text] behavior at low frequencies ([Formula: see text]) and saturates at higher frequencies. We also observed the Holstein mechanism, however, with different power laws from that in the case of metals; (2) at higher frequencies, [Formula: see text], and higher temperatures [Formula: see text], we observed that the generalized Drude scattering rate is linear in temperature. In addition, several other results are also obtained. With the experimental advancement of this field, these results should be experimentally tested.

Radiotherapy Proton Interactions in Matter

OpenAIRE

Gottschalk, Bernard

2018-01-01

A survey of physics useful to proton radiotherapy, centered on stopping, scattering and hard scatters: 1. Introduction 2. The fundamental formula dose = fluence x mass stopping power. Practical units, comments on effective stopping power. 3. Range: experimental definition, Beth-Bloch CSDA theory, range-energy tables and approximations, range straggling. 4. Multiple Coulomb Scattering: suggested reading, elements of Moliere theory, the Gaussian approximation, scattering power. 5. Hard scatters...

An introduction to presheaves with transfers and motivic cohomology

Energy Technology Data Exchange (ETDEWEB)

Biglari, Shahram [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)

2001-08-01

The construction of motivic cohomology theories has generated a lot of new research activities in algebraic geometry in the last years. In this work some preliminary ideas of schemes and morphisms, some homological algebra in abelian categories and Grothendieck topologies are given.The connection between Milnor and Quillen K-theory of fields is defined as well as the motivic cohomology and Bloch's higher Chou groups.

Electric- and magnetic-dipole contributions to a theory of radiation reaction field and atom self-energy: An operator reaction field

International Nuclear Information System (INIS)

Obada, A.S.F.; Mahran, M.H.

1982-08-01

The consequences of including magnetic-dipole contributions, besides the electric-dipole, are considered in the operators for the radiation field. The Bloch equations which describe the two-level atom operators are modified. These equations together with the field operators are discussed, and the contributions are manifested. The spectrum for spontaneous emission and a generalized dynamical Stark effect are obtained. Rabi frequency is modified. (author)

Mass and charge identification of fragments detected with the Chimera Silicon-CsI(Tl) telescopes

Energy Technology Data Exchange (ETDEWEB)

Le Neindre, N.; Alderighi, M.; Anzalone, A.; Barna, R.; Bartolucci, M.; Berceanu, I.; Borderie, B.; Bougault, R.; Bruno, M.; Cardella, G.; Cavallaro, S.; D' Agostino, M. E-mail: dagostino@bo.infn.it; Dayras, R.; De Filippo, E.; De Pasquale, D.; Geraci, E.; Giustolisi, F.; Grzeszczuk, A.; Guazzoni, P.; Guinet, D.; Iacono-Manno, M.; Italiano, A.; Kowalski, S.; Lanchais, A.; Lanzano, G.; Lanzalone, G.; Li, S.; Lo Nigro, S.; Maiolino, C.; Manfredi, G.; Moisa, D.; Pagano, A.; Papa, M.; Paduszynski, T.; Petrovici, M.; Piasecki, E.; Pirrone, S.; Politi, G.; Pop, A.; Porto, F.; Rivet, M.F.; Rosato, E.; Russo, S.; Sambataro, S.; Sechi, G.; Simion, V.; Sperduto, M.L.; Steckmeyer, J.C.; Sutera, C.; Trifiro, A.; Tassan-Got, L.; Trimarchi, M.; Vannini, G.; Vigilante, M.; Wilczynski, J.; Wu, H.; Xiao, Z.; Zetta, L.; Zipper, W

2002-09-01

Mass and charge identification of charged products detected with Silicon-CsI(Tl) telescopes of the Chimera apparatus are presented. An identification function, based on the Bethe-Bloch formula, is used to fit empirical correlations between {delta}E and E ADC readings, in order to determine, event by event, the atomic and mass numbers of the detected charged reaction products prior to energy calibration.

The Faraday effect in two-dimensional magneto-photonic crystals

International Nuclear Information System (INIS)

Merzlikin, A.M.; Vinogradov, A.P.; Inoue, M.; Khanikaev, A.B.; Granovsky, A.B.

2006-01-01

The necessary conditions for the observation of the Faraday effect in 2D magneto-photonic crystals are discussed. It is found. that the Faraday effect may be observed in the directions where any couple of the wave vectors of the harmonics consisting the Bloch waves of TE and TM solutions in zero magnetic field are identical. This direction corresponds neither to Faraday nor to Voigt geometry

The Faraday effect in two-dimensional magneto-photonic crystals

Energy Technology Data Exchange (ETDEWEB)

Merzlikin, A.M. [Institute for Theoretical and Applied Electromagnetism, OIVT, Russian Academy of Sciences, Izhorskay 13/19, Moscow 125412 (Russian Federation)]. E-mail: merzlikin_a@mail.ru; Vinogradov, A.P. [Institute for Theoretical and Applied Electromagnetism, OIVT, Russian Academy of Sciences, Izhorskay 13/19, Moscow 125412 (Russian Federation); Inoue, M. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1, Hibari-Ga-Oka, Tempaku, Toyohashi 441-8580 (Japan); Khanikaev, A.B. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1, Hibari-Ga-Oka, Tempaku, Toyohashi 441-8580 (Japan); Granovsky, A.B. [Faculty of Physics, Lomonosov Moscow State University, Leninski Gory, Moscow 119992 (Russian Federation)

2006-05-15

The necessary conditions for the observation of the Faraday effect in 2D magneto-photonic crystals are discussed. It is found. that the Faraday effect may be observed in the directions where any couple of the wave vectors of the harmonics consisting the Bloch waves of TE and TM solutions in zero magnetic field are identical. This direction corresponds neither to Faraday nor to Voigt geometry.

Kuidas üheskoos ajalugu mäletada? / Taavi Arus

Index Scriptorium Estoniae

Arus, Taavi

2007-01-01

Tallinna Ülikoolis 26. ja 27. juulil toimuvast loengusarjast, kus astuvad loengutega üles ajaloolased Peter Burke, Leonidas Donskis ja Maurice Bloch. Tallinna Ülikooli rektori professor Rein Raua sõnul on nimetatud loengusari üks selle suve intellektuaalseid kõrghetki. Loengutele järgnevad arutelud, mida juhivad vastavalt Tallinna Ülikooli Eesti Humanitaarinstituudi lektor Marek Tamm, filosoofiaprofessor Tõnu Viik ning antropoloogiadotsent Lorenzo Canas

The semi classical laser theory and some applications of laser

International Nuclear Information System (INIS)

Abdalla, Abbaker Ali

1995-04-01

The semi classical laser theory is concerned with the interaction between light and matter in such a way that the matter is treated quantum-mechanically whereas light is treated in terms of the classical electromagnetic equations. In this work the Maxwell-Bloch equations are employed to describe the interaction between light and matter. Applications of the theory as well as different types of lasers are reviewed. (Author)

An introduction to presheaves with transfers and motivic cohomology

International Nuclear Information System (INIS)

Biglari, Shahram

2001-08-01

The construction of motivic cohomology theories has generated a lot of new research activities in algebraic geometry in the last years. In this work some preliminary ideas of schemes and morphisms, some homological algebra in abelian categories and Grothendieck topologies are given.The connection between Milnor and Quillen K-theory of fields is defined as well as the motivic cohomology and Bloch's higher Chou groups

Physics of Magnetic Resonance. Chapter 14

Energy Technology Data Exchange (ETDEWEB)

Song, Hee Kwon [Hospital of the University of Pennsylvania, Philadelphia (United States)

2014-09-15

The discovery of nuclear magnetic resonance (NMR), a property of nuclei in a magnetic field where they are able to absorb applied radiofrequency (RF) energy and subsequently release it at a specific frequency, goes back many decades to the early 1900s. Physicist Isidor I. Rabi, fascinated by the work of Otto Stern and Walther Gerlach which demonstrated that particles have intrinsic quantum properties, delved into the magnetic properties of nuclei, and in 1938 Rabi discovered the phenomenon of NMR. Several years later, in 1946, Felix Bloch and Edward Purcell refined the methods and successfully measured the NMR signal from liquids and solids. For their discoveries, Rabi received the Nobel Prize for physics in 1944 and Bloch and Purcell in 1952. While Rabi, Bloch, Purcell and other physicists working in this field had laid the foundations, a major discovery that transformed the NMR phenomenon for imaging was not made until 1973, when Paul Lauterbur developed a method for spatially encoding the NMR signal by utilizing linear magnetic field gradients. About the same time, Peter Mansfield had also discovered a means of determining the spatial structure of solids by introducing a linear gradient across the object. The idea of applying magnetic field gradients to induce spatially varying resonance frequencies to resolve the spatial distribution of magnetization was a major milestone and the beginning of magnetic resonance imaging (MRI). For their work, Lauterbur and Mansfield were awarded the Nobel Prize for medicine in 2003. Since its discovery, MRI has quickly become one of the most important medical imaging devices available to physicians today. Unlike other imaging modalities, such as X ray and computed tomography, MRI does not involve ionizing radiation. MRI also offers superior soft tissue contrast that is not possible with other imaging modalities. Furthermore, in MRI, the desired level of image contrast among different tissues can often be precisely controlled

Creatine kinase rate constant in the human heart measured with 3D-localization at 7 tesla.

Science.gov (United States)

Clarke, William T; Robson, Matthew D; Neubauer, Stefan; Rodgers, Christopher T

2017-07-01

We present a new Bloch-Siegert four Angle Saturation Transfer (BOAST) method for measuring the creatine kinase (CK) first-order effective rate constant k f in human myocardium at 7 tesla (T). BOAST combines a variant of the four-angle saturation transfer (FAST) method using amplitude-modulated radiofrequency pulses, phosphorus Bloch-Siegert B1+-mapping to determine the per-voxel flip angles, and nonlinear fitting to Bloch simulations for postprocessing. Optimal flip angles and repetition time parameters were determined from Monte Carlo simulations. BOAST was validated in the calf muscle of two volunteers at 3T and 7T. The myocardial CK forward rate constant was then measured in 10 volunteers at 7T in 82 min (after 1 H localization). BOAST kfCK values were 0.281 ± 0.002 s -1 in the calf and 0.35 ± 0.05 s -1 in myocardium. These are consistent with literature values from lower fields. Using a literature values for adenosine triphosphate concentration, we computed CK flux values of 4.55 ± 1.52 mmol kg -1 s -1 . The sensitive volume for BOAST depends on the B 1 inhomogeneity of the transmit coil. BOAST enables measurement of the CK rate constant in the human heart at 7T, with spatial localization in three dimensions to 5.6 mL voxels, using a 10-cm loop coil. Magn Reson Med 78:20-32, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Biochemical composition of the alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785)

Science.gov (United States)

Sanaye, Sushant Vilas; Pawar, Ashwini Pandurang; Rivonker, Chandrasheker Umanath; Sreepada, Rayadurga Anantha; Ansari, Zakir Ali; Ram, Anirudh

2017-11-01

Considering the economic importance in traditional Chinese medicine (TCM) and lack of baseline information, we evaluated the proximate composition, fatty acid and amino acid profiles, trace element content and C:N ratio in the alligator pipefish, Syngnathoides biaculeatus. Amongst proximate principals, a crude protein formed the major biochemical component ((58.9±2.2)% dry weight). Mean percent concentrations (dry weight) of other components such as a total lipid (TL), ash and nitrogen-free extract measured were, (1.8±0.2)%, (19.2±2.2)% and (20.1±0.45)%, respectively. The fatty acid profile revealed the presence of 27 saturated fatty acids (SFA) with 13 straight-chained and 14 branched-chained, 28 unsaturated fatty acids (UFA) with 14 monounsaturated and 14 polyunsaturated and nine other minor fatty acids. Mean percent contributions of total SFAs and UFAs to TL were found to be (55.41±0.24)% and (44.05±0.25)%, respectively. Altogether, 16 different amino acids with an equal number of essential (EAA) and non-essential (NAA) ones were identified. Percent contributions by EAA and NAA to the total amino acid content were 38.11% and 61.89%, respectively. Trace metal concentrations in S. biaculeatus were generally low and their distribution followed the order, Mg>Fe>Zn>Mn>Cu>Cr>Ni>Hg>Co. The C:N ratio was (4.37±0.04)%. The profile of major biochemical constituents in alligator pipefish, S. biaculeatus revealed its potential use in TCM as well as a nutritional diet for human consumption. The results of the study would also form the basis for formulation and optimization of diets for the culture of S. biaculeatus.

A Compressed Sensing Framework for Magnetic Resonance Fingerprinting

OpenAIRE

Davies, Mike; Puy, Gilles; Vandergheynst, Pierre; Wiaux, Yves

2013-01-01

Inspired by the recently proposed Magnetic Resonance Fingerprinting (MRF) technique, we develop a principled compressed sensing framework for quantitative MRI. The three key components are: a random pulse excitation sequence following the MRF technique; a random EPI subsampling strategy and an iterative projection algorithm that imposes consistency with the Bloch equations. We show that theoretically, as long as the excitation sequence possesses an appropriate form of persistent excitation, w...

Quantum memory for nonstationary light fields based on controlled reversible inhomogeneous broadening

International Nuclear Information System (INIS)

Kraus, B.; Tittel, W.; Gisin, N.; Nilsson, M.; Kroell, S.; Cirac, J. I.

2006-01-01

We propose a method for efficient storage and recall of arbitrary nonstationary light fields, such as, for instance, single photon time-bin qubits or intense fields, in optically dense atomic ensembles. Our approach to quantum memory is based on controlled, reversible, inhomogeneous broadening and relies on a hidden time-reversal symmetry of the optical Bloch equations describing the propagation of the light field. We briefly discuss experimental realizations of our proposal

Initial States: IR and Collinear Divergences

International Nuclear Information System (INIS)

Lavelle, Martin; McMullan, David

2007-01-01

The standard approach to the infra-red problem is to use the Bloch-Nordsieck trick to handle soft divergences and the Lee-Nauenberg (LN) theorem for collinear singularities. We show that this is inconsistent in the presence of massless initial particles. Furthermore, we show that using the LN theorem with such initial states introduces a non-convergent infinite series of diagrams at any fixed order in perturbation theory

Dollar Summary of Prime Contract Awards by State, Place, and Contractor, FY84, Part 5, (Ashton, Rhode Island-Sinclair, Wyoming).

Science.gov (United States)

1984-01-01

BERGSTROM AIR FORCE CITY OF AUSTIN 4,745 4,745 CPT CORPORATION 66 66 CSR CONTRACTING INC 554 554 DAILEY...317 STARBUCK INDUSTRIAL PUMP SALES COM 147 147 RIDGE CONSTRUCTION CO INC 240 240 SIUSLAW CONSTRUCTION 352 352 SPOONER MECHANICAL CONTRS 226 226 TOTAL... STARBUCK 965 965 STEVENSON BLOCH LUMBER COMPANY 44 44 SUMNER SPACE TECH ENGINEERING INC 762 762 SUNNYSIDE INDEPENDENT FOOD PROCSSRS CORP 86 66 TACOMA

Picasso kõrge hind / Riina Robinson

Index Scriptorium Estoniae

Robinson, Riina

2007-01-01

Pablo Picassost, tema loomingust, 2003.a Malagas Picasso muuseumi ja kunstniku sünnikodu avamisest, maailma kallemailt müüdud maalide TOP 10-sse kuuluvatest maalidest "Poiss piibuga" (1905) ja "Dora Maar kassiga" (1941), hindadest. Maailma kalleimad oksjonil müüdud maalid: I - Jackson Pollocki "Nr.5, 1948" (hind:140 miljonit dollarit), II - William De Kooningi "Woman III" (1952-53), III - Gustav Klimti "Adele Bloch-Bauer I portree" (1907)

Engineered Potentials and Dynamics of Ultracold Quantum Gases Under the Microscope

Science.gov (United States)

2014-05-09

CONTRACT OR GRANT NUMBER: DESCRIPTION OF MATERIAL INSTITUTION: PRINCIPAL INVESTIGATOR: Paola Cappellaro TYPE REPORT: Ph.D. Dissertation PERIOD...CONTRACT NUMBER Engineered potentials and dynamics of ulu·acold quantum gases W911NF-11-1-0400 under the microscope Sb. GRANT NUMBER Sc. PROGRAM...Schnorrberger, M. Moreno- Cardoner , S. Fölling, and I. Bloch, “Counting atoms using interaction blockade in an optical superlat- tice,” Phys. Rev. Lett

Jacob's ladder of approximations to paraxial dynamic electron scattering

OpenAIRE

Lubk, A.; Rusz, Jan

2015-01-01

Dynamical scattering theory describes the dominant scattering process of beam electrons at targets in the transmission electron microscope (TEM). Hence, practically every quantitative TEM study has to consider its ramifications, typically by some approximate modeling. Here, we elaborate on a hierarchy within the various approximations focusing on the two principal approaches used in practice, Bloch wave and multislice. We reveal characteristic differences in the capability of these methods to...

Elisa Alicia Lynch: a Dama de Aço do Paraguai * Elisa Alicia Lynch: the Steel ‘S Lady of Paraguay

OpenAIRE

Frota, Luciara Silveira de Aragão e

2015-01-01

Este trabalho mostra uma nova visão da irlandesa Elisa Alicia Lynch, longe da figura de prostituta manipuladora que incitou o Marechal Solano López no começo da Guerra do Paraguai. Dentro de uma corrente revisionista histórica, apoiada em Marc Bloch, propõe uma nova análise de seu papel na vida de Solano López e do Paraguai, comentando a literatura sobre o assunto.

Spatial and temporal characterization of fish assemblages in a tropical coastal system influenced by freshwater inputs: northwestern Yucatan peninsula

Directory of Open Access Journals (Sweden)

Daniel Arceo-Carranza

2009-06-01

Full Text Available Coastal lagoons are important systems for freshwater, estuarine and marine organisms; they are considered important zones of reproduction, nursery and feeding for many fish species. The present study investigates the fish assemblages of the natural reserve of Dzilam and their relationship with the hydrologic variables. A total of 6 474 individuals (81 species were collected, contributing with more than 50% considering the Importance Value Index (IVI, Sphoeroides testudineus, Fundulus persimilis, Anchoa mitchilli, Eucinostomus gula, Eucinostomus argenteus and Mugil trichodon. Differences in species composition were found between seasons the highest during the cold fronts. Spatially, differences were related with the presence of freshwater seeps, the highest in the ecological characterized eastern part and the lowest with higher difference in specific composition located in the western part of the internal zone, due to a higher abundance and dominance of L. rhomboides. Salinity and temperature were the variables that presented a higher influence in the distribution of some pelagic species such as A. mitchilli and A. hepsetus. Because of the abundant freshwater seeps characteristic of the coastal lagoons of Yucatan Peninsula their community structure and fish assemblage display spatial and temporal differences in specific composition. Rev. Biol. Trop. 57 (1-2: 89-103. Epub 2009 June 30.Las lagunas costeras son sistemas importantes para muchas especies de organismos dulceacuícolas, estuarinos y marinos, ya que son consideradas zonas de reproducción, refugio y alimentación de muchas especies de peces. El presente estudio analizó los ensamblajes de la comunidad íctica de la reserva de Dzilam y su relación con las variables hidrológicas. Se capturaron un total de 6 474 individuos (81 especies, en donde Sphoeroides testudineus, Fundulus persimilis, Anchoa mitchilli, Eucinostomus gula, Eucinostomus argenteus and Mugil trichodon contribuyeron con m

18 octobre 2013 - Le Préfet de l’Ain L. Touvet signe le livre d'or avec le Directeur général du CERN R. Heuer et le Chef du Département Technologie F. Bordry. Photo de groupe, de gauche à droite: T. Kupisz, Secrétaire général de la sous préfecture de Gex; L. Miralles, Chef du Département Infrastructure et services généraux; F. Eder, Délégué aux Relations avec les Etats hôtes; S. Donnot, Sous-préfet de Gex; L. Touvet, Préfet de l'Ain; E. Sches, Sous-préfète de Nantua; E.Gröniger-Voss, Conseiller juridique du CERN; R. Heuer, Directeur général; F. Bordry, Chef du Département Technologie et P. Bloch, Chef du Département Physique.

CERN Multimedia

Anna Pantelia

2013-01-01

18 octobre 2013 - Le Préfet de l’Ain L. Touvet signe le livre d'or avec le Directeur général du CERN R. Heuer et le Chef du Département Technologie F. Bordry. Photo de groupe, de gauche à droite: T. Kupisz,\tSecrétaire général de la sous préfecture de Gex; L. Miralles, Chef du Département Infrastructure et services généraux; F. Eder, Délégué aux Relations avec les Etats hôtes; S. Donnot, Sous-préfet de Gex; L. Touvet, Préfet de l'Ain; E. Sches, Sous-préfète de Nantua; E.Gröniger-Voss, Conseiller juridique du CERN; R. Heuer, Directeur général; F. Bordry, Chef du Département Technologie et P. Bloch, Chef du Département Physique.

Some Advances in the Circuit Modeling of Extraordinary Optical Transmission

Directory of Open Access Journals (Sweden)

F. Medina

2009-06-01

Full Text Available The phenomenon of extraordinary optical transmission (EOT through electrically small holes perforated on opaque metal screens has been a hot topic in the optics community for more than one decade. This experimentally observed frequency-selective enhanced transmission of electromagnetic power through holes, for which classical Bethe's theory predicts very poor transmission, later attracted the attention of engineers working on microwave engineering or applied electromagnetics. Extraordinary transmission was first linked to the plasma-like behavior of metals at optical frequencies. However, the primary role played by the periodicity of the distribution of holes was soon made evident, in such a way that extraordinary transmission was disconnected from the particular behavior of metals at optical frequencies. Indeed, the same phenomenon has been observed in the microwave and millimeter wave regime, for instance. Nowadays, the most commonly accepted theory explains EOT in terms of the interaction of the impinging plane wave with the surface plasmon-polariton-Bloch waves (SPP-Bloch supported by the periodically perforated plate. The authors of this paper have recently proposed an alternative model whose details will be briefly summarized here. A parametric study of the predictions of the model and some new potential extensions will be reported to provide additional insight.

30 July 2012 - Prime Minister of France, Mr. Jean-Marc Ayrault, visits CERN

CERN Multimedia

Maximillien Brice

2012-01-01

Ligne d'accueil: Directeur général, R. Heuer présente: Directeur S. Myers, Chef des Relations internationales F. Pauss et Chefs de Département P. Bloch et A.-S. Catherin ; Représentants du CEA et du CNRS des 4 experiences LHC : J.-L. Faure, L. Fayard, C. Guyot, M.-H. Schune, Y. Schutz, Y. Sirois, Protocole CERN S. Molinari. Les autorités locales saluent le Premier ministre: M. Christophe Bouvier, maire de Cessy, M. Rachel Mazuir, sénateur de l'Ain, président du CG01, M. Etienne Blanc, député de l'Ain, maire de Divonne les Bains, et Mme Yvette Brachet, conseillère régionale représentant M. Jean-Jack Queyranne, président du CR Rhône Alpes. CERN-GE-1207163 32: dans le tunnel du LHC au Point 5: R. Garoby, Chef adjoint du département Faisceaux P. Lebrunm, Attaché à la Direction P. Bloch, Chef du département Physique J. Bertrand, (représente Alain Fuchs),CNRS Y. Sirois, Collaboration CMS, Responsable pour la France, Directeur de Recherche au CNRS, LLR Ecole Polytechnique J.-Y. Le Deaut, Dépu...

Validity of the electrical model representation of the effects of nuclear magnetic resonance (1961); Validite de la representation par modele electrique des effets de resonance magnetique nucleaire (1961)

Energy Technology Data Exchange (ETDEWEB)

Bonnet, G [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1961-07-01

When studying the behaviour of a magnetic resonance transducer formed by the association of an electrical network and of a set of nuclear spins, it is possible to bring about a representation that is analytically equivalent by means of an entirely electrical model, available for transients as well as steady-state. A detailed study of the validity conditions justifies its use in most cases. Also proposed is a linearity criterion of Bloch's equations in transient state that is simply the prolongation of the well-known condition of non-saturation in the steady-state. (author) [French] L'etude du comportement d'un transducteur a resonance magnetique forme de l'association d'un reseau electrique et d'un ensemble de noyaux dotes de spin, montre qu'il est possible d'en deduire une representation analytiquement equivalente au moyen d'un modele entierement electrique utilisable pour un regime transitoire aussi bien que pour un regime permanent. Une etude detaillee des conditions de validite permet d'en justifier l'emploi dans la majorite des cas. On propose enfin un critere de linearite des equations de Bloch en regime transitoire, qui constitue un prolongement de la condition connue de non-saturation en regime stationnaire. (auteur)

Influence of temperature on the critical in-plane field range for VBLs in the walls of hard domains

International Nuclear Information System (INIS)

Nie, X.F.; Guo, G.X.; Xu, J.P.; Liu, S.P.; Wang, L.N.; Huo, S.G.

2006-01-01

The influence of temperature on the critical in-plane field range for vertical Bloch lines in the walls of three kinds of hard domains is investigated experimentally. It is found that for each kind of three hard domains, there exists a critical in-plane field range, i. e. [H ip (1) (T),H ip (2) (T)], which depends on temperatures and in which vertical Bloch lines are unstable. Here, H ip (1) (T) is the initial critical in-plane field where VBLs in the walls of three kinds of hard domains are annihilated, and H ip (2) (T) is the lowest in-plane field where VBLs in their corresponding hard domains are annihilated completely. H ip (1) (T), H ip (2) (T) and [H ip (1) (T),H ip (2) (T)], all decrease as the temperature increase. Furthermore, H ip (1) (T) and H ip (2) (T) reach zero at T 0 1 and T 0 , respectively. In addition, there exists a relationship among them, when T is unchanged, H ip (1) (T) of the three kinds of hard domains (ordinary hard bubbles (OHB), first kind of dumbbell domain (ID) and second kind of dumbbell domains (IID)) decrease successively, and theirH ip (2) (T) are the same

The dc electrical conductivity calculation purely from the dissipative component of the ac conductivity II. formula for conductors with static scatterers

International Nuclear Information System (INIS)

Milinski, Nikola; Milinski, Eduard

2001-01-01

While the first part of this work was devoted to the conceptual and most crucial questions of the dc electrical conductivity σ, the present second part is devoted to the technical questions of the theory, to elaboration of the concept to the particular systems. The conducting system to be investigated has been defined here by five suppositions (postulates), rather general to include the systems of practical interest, like metals in solid and liquid phase are, and the amorphous conductors, like the alloys and conducting glasses are. A formula for dc conductivity calculation has been derived, which gives σ in terms of the matrix elements / k +g/F/Ψ k >/ 2 , where F is scattering force, and Ψ k +g, Ψ k , are the Bloch functions. For the case when Bloch functions are approximated by plane waves, an approximate formula for σ has been obtained in a more tractable form. Specific to our concept is the inclusion of an equation constitutive to σ calculation, which also has been elaborated for the considered system, to the stage suitable for practical application, σ calculation in conjunction with the mentioned constitutive equation is the most important innovative element of our concept, and we expect it will lead to substantial advance in research of this subject. (authors)

Dynamical electrical conductivity of graphene

Science.gov (United States)

Rani, Luxmi; Singh, Navinder

2017-06-01

For graphene (a Dirac material) it has been theoretically predicted and experimentally observed that DC resistivity is proportional to T 4 when the temperature is much less than Bloch-Grüneisen temperature ({{ \\Theta }\\text{BG}} ) and T-linear in the opposite case (T\\gg {{ \\Theta }\\text{BG}} ). Going beyond this case, we investigate the dynamical electrical conductivity in graphene using the powerful method of the memory function formalism. In the zero frequency regime, we obtain the above mentioned behavior which was previously obtained using the Bloch-Boltzmann kinetic equation. In the finite frequency regime, we obtain several new results: (1) the generalized Drude scattering rate, in the zero temperature limit, shows {ω4} behavior at low frequencies (ω \\ll {{k}\\text{B}}{{ \\Theta }\\text{BG}}/\\hbar ) and saturates at higher frequencies. We also observed the Holstein mechanism, however, with different power laws from that in the case of metals; (2) at higher frequencies, ω \\gg {{k}\\text{B}}{{ \\Theta }\\text{BG}}/\\hbar , and higher temperatures T\\gg {{ \\Theta }\\text{BG}} , we observed that the generalized Drude scattering rate is linear in temperature. In addition, several other results are also obtained. With the experimental advancement of this field, these results should be experimentally tested.

Optical pulse dynamics for quantum-dot logic operations in a photonic-crystal waveguide

Energy Technology Data Exchange (ETDEWEB)

Ma, Xun; John, Sajeev [Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 Canada (Canada)

2011-11-15

We numerically demonstrate all-optical logic operations with quantum dots (QDs) embedded in a bimodal photonic-crystal waveguide using Maxwell-Bloch equations in a slowly varying envelope approximation (SVEA). The two-level QD excitation level is controlled by one or more femtojoule optical driving pulses passing through the waveguide. Specific logic operations depend on the relative pulse strengths and their detunings from an inhomogeneouslly broadened (about 1% for QD transitions centered at 1.5 {mu}m) QD transition. This excitation controlled two-level medium then determines passage of subsequent probe optical pulses. Envelope equations for electromagnetic waves in the linear dispersion and cutoff waveguide modes are derived to simplify solution of the coupled Maxwell-Bloch equations in the waveguide. These determine the quantum mechanical evolution of the QD excitation and its polarization, driven by classical electromagnetic (EM) pulses near a sharp discontinuity in the EM density of states of the bimodal waveguide. Different configurations of the driving pulses lead to distinctive relations between driving pulse strength and probe pulse passage, representing all-optical logic and, or, and not operations. Simulation results demonstrate that such operations can be done on picosecond time scales and within a waveguide length of about 10 {mu}m in a photonic-band-gap (PBG) optical microchip.

SHAPIRO EFFECT IN INDUCTIVE QUANTUM CIRCUITS WITH CHARGE DISCRETENESS EFECTO SHAPIRO EN CIRCUITOS CUÁNTICOS INDUCTIVOS CON CARGA DISCRETA

Directory of Open Access Journals (Sweden)

Kristopher Chandía Valenzuela

2006-08-01

Full Text Available ABSTRACT As it is known, quantum inductive circuits with charge discreteness show Bloch-like oscillations in electrical current under a dc external voltage. In this paper, the effect of a superimposed ac voltage in the circuit is considered. The Shapiro effect is found to be related to the existence of resonance. Surprisingly, in the limit of low frequency (no resonance, the electrical averaged current exists and has always the same sign. Eventually this allows for an experimental method to measure discrete charge effect in quantum mesoscopic circuits.RESUMEN Es sabido que circuitos cuánticos inductivos con carga discreta, cuando se someten a un voltaje continuo externo, presentan oscilaciones de Bloch en la corriente. En este trabajo se considera, además, la superposición de un voltaje alterno en el circuito. El efecto Shapiro, relacionado con la existencia de resonancias, es encontrado de modo explícito. Sorprendentemente, en el límite de bajas frecuencias (sin resonancia la corriente eléctrica promediada existe y tiene siempre el mismo signo. Eventualmente, esto entrega un método experimental para medir los efectos de la discretización de la carga en circuitos cuánticos mesosocópicos.

CBED contrast in the lower order Laue zone

International Nuclear Information System (INIS)

Rossouw, C.J.; Maunders, C.J.; Whitfield, H.J.; Etheridge, J.

2006-01-01

Contrast in a systematic arrangement of lower order Laue zone (LOLZ) beams is reported and analysed using a Bloch wave description. Observations are reported for hexagonal barium ruthenium zirconate (Ba 4 Ru 3 ZrO 12 ) and barium ruthenium titanate (Ba 3 Ti 2 RuO 9 ), both near the c -axis orientation. The specific scattering dynamics invoked by this diffraction geometry may have novel uses in the exploration of crystallographic parameters

Effects of crop rotation on weed density, biomass and yield of wheat (Titicum aestivum L.)

OpenAIRE

A. Zareafeizabadi; H.R. Rostamzadeh

2016-01-01

In order to study the weed populations in wheat, under different crop rotations an experiment was carried out at Agricultural Research Station of Jolgeh Rokh, Iran. During growing season this project was done in five years, based on Randomized Complete Bloch Design with three replications, on Crop rotations included: wheat monoculture for the whole period (WWWWW), wheat- wheat- wheat- canola- wheat (WWWCW), wheat- sugar beet- wheat-sugar beet- wheat (WSWSW), wheat- potato- wheat- potato- whea...

Secondary electron emission induced by channeled relativistic electrons in a (1 1 0) Si crystal

International Nuclear Information System (INIS)

Korotchenko, K.B.; Kunashenko, Yu P.; Tukhfatullin, T.A.

2012-01-01

A new effect that accompanies electrons channeled in a crystal is considered. This phenomenon was previously predicted was called channeling secondary electron emission (CSEE). The exact CSEE cross-section on the basis of using the exact Bloch wave function of electron channeled in a crystal is obtained. The detailed investigation of CSEE cross-section is performed. It is shown that angular distribution of electrons emitted due to CSEE has a complex form.

Hoarding behavior among young children with obsessive-compulsive disorder

OpenAIRE

Frank, Hannah; Stewart, Elyse; Walther, Michael; Benito, Kristen; Freeman, Jennifer; Conelea, Christ; Garci, Abbe

2013-01-01

Previous research has shown that among the various subtypes of obsessive-compulsive disorder (OCD), adults (e.g. Frost, Krause & Steketee, 1996) and older children and adolescents (Bloch et al., 2009; Storch et al., 2007) with problematic hoarding have distinct features and a poor treatment prognosis. However, there is limited information on the phenomenology and prevalence of hoarding behaviors in young children. The present study characterizes children ages 10 and under who present with OCD...

Mode-Locking in Broad-Area Semiconductor Lasers Enhanced by Picosecond-Pulse Injection

OpenAIRE

Kaiser, J; Fischer, I; Elsasser, W; Gehrig, E; Hess, O

2004-01-01

We present combined experimental and theoretical investigations of the picosecond emission dynamics of broad-area semiconductor lasers (BALs). We enhance the weak longitudinal self-mode-locking that is inherent to BALs by injecting a single optical 50-ps pulse, which triggers the output of a distinct regular train of 13-ps pulses. Modeling based on multimode Maxwell-Bloch equations illustrates how the dynamic interaction of the injected pulse with the internal laser field efficiently couples ...

19th November 2010 - President of Application of Detectors and Accelerators to Medecine A. Colussi signs the guest book with CERN Director-General R. Heuer, on the occassion of the inauguration of the First Unit of the Linac for Image Guided Hadron Therapy (LIGHT) in building 904.

CERN Multimedia

Maximilien Brice

2010-01-01

CERN-EX-1011305 14: from left to right: ADAM Vice President D. Campi, ADAM Scientific Committee Member G. Brianti, ADAM Scientific Committee Chair U. Amaldi, CERN Director-General R. Heuer, ADAM President A. Colussi, Italian Ambassador to the U.N. L. Mirachian, CERN Director for Research and Scientific Computing S. Bertolucci, CERN Physics Department Head P. Bloch, ADAM Board of Directors Member C. Lamprecht, ADAM Scientific Committee Member F. Sauli, P. Pearce and J. Bernier.

Electroweak evolution equations

International Nuclear Information System (INIS)

Ciafaloni, Paolo; Comelli, Denis

2005-01-01

Enlarging a previous analysis, where only fermions and transverse gauge bosons were taken into account, we write down infrared-collinear evolution equations for the Standard Model of electroweak interactions computing the full set of splitting functions. Due to the presence of double logs which are characteristic of electroweak interactions (Bloch-Nordsieck violation), new infrared singular splitting functions have to be introduced. We also include corrections related to the third generation Yukawa couplings

A many-particle quantum-kinetic formalism for describing properties of light emitters in frozen dielectrics

Directory of Open Access Journals (Sweden)

Gladush M.G.

2017-01-01

Full Text Available A many particle quantum-kinetic formalism is suggested to derive the Maxwell-Bloch-type equations which describe the interaction of quantum emitters with light in a frozen dielectric. It is shown that the quantum-kinetic formalism can meet the concept of local variations of dielectric properties and their influence on the emitter. The definitions of the local response and the effective refractive index in macroscopically homogeneous media are discussed.

Compressing the hidden variable space of a qubit

OpenAIRE

Montina, Alberto

2010-01-01

In previously exhibited hidden variable models of quantum state preparation and measurement, the number of continuous hidden variables describing the actual state of a single realization is never smaller than the quantum state manifold dimension. We introduce a simple model for a qubit whose hidden variable space is one-dimensional, i.e., smaller than the two-dimensional Bloch sphere. The hidden variable probability distributions associated with the quantum states satisfy reasonable criteria ...

On a simple model of the photonic or photonic crystal

International Nuclear Information System (INIS)

Kosevich, A.M.

2001-01-01

A model is proposed for a one-dimensional dielectric or superlattice (SL) that relatively simply describes the frequency spectrum of electromagnetic or acoustic waves. The band frequency spectrum is reduced to minibands contracting with increasing frequency. A procedure is suggested for obtaining local states near a defect in a SL, and the simplest of these states is described. Conditions for the initiation of Bloch oscillations of a wave packet in a SL are discussed

Ultrafast Gain Dynamics in Quantum Dot Amplifiers: Theoretical Analysis and Experimental Investigations

DEFF Research Database (Denmark)

Poel, Mike van der; Gehrig, Edeltraud; Hess, Ortwin

2005-01-01

Ultrafast gain dynamics in an optical amplifier with an active layer of self-organized quantum dots (QDs) emitting near 1.3$muhbox m$is characterized experimentally in a pump-probe experiment and modeled theoretically on the basis of QD Maxwell–Bloch equations. Experiment and theory are in good......$factor) is theoretically predicted and demonstrated in the experiments. The fundamental analysis reveals the underlying physical processes and indicates limitations to QD-based devices....

Inner bremsstrahlung accompanying beta decay of 170Tm

International Nuclear Information System (INIS)

Sanjeeviah, H.; Venkataramaiah, P.; Gundu Rao, K.S.

1980-01-01

The inner bremmsstrahlung (IB) spectrum accompanying beta decay of 170 Tm was measured using magnetic deflection technique. The raw spectrum was unfolded using the procedure of Liden and Starfelt. The unfolded IB spectrum was compared with the theories of Knipp and Uhlenbeck and Bloch; Lewis and Ford. Comparison was made with Ford and Martin theory in order to estimate the contribution of detour transitions to the IB spectrum of 170 Tm. (author)

Transporte electronico en nanoestructuras de carbono

Science.gov (United States)

Jodar Ferrandez, Esther

transmission function. We analyze the influence of the width of the cavity and the distance between them (in the case of multiple cavities). Some interesting results are obtained in these calculations which have been published in international journals (Jodar et al. 2006, Jodar y Perez-Garrido 2007). We emphasize the presence of quasi-localized states in the cavities, which affects to the transmission function, the behaviour of some cavities formed with semi-conductor as quantum dots, or the study of the evolution of the system with multiple cavities to the limit of infinite cavities. (4) Chapter 4: Bloch Oscillations. In this chapter we investigate the properties of carbon nanotubes under a constant electric field. This configuration show Bloch oscillations, according to the work of Bloch and Zener. We study here the dynamics of these oscillations for different geometries as a function of the electric field applied. Specially, the behaviour of the occupation probability and the averaged quadratic displacement as a function of time. We have not found bibliography that deals with this phenomenon in Carbon Nanotubes, which is the aim of this chapter. We first study the behaviour of electrons in pure carbon nanotubes in a constant electric field, for different lengths of the CNT and different values of the electric field applied. We show how wavefunctions oscillate with a period that coincides with that given by theoretical expressions of Bloch oscillations for linear chains of atoms. Besides, we show the different kind of behaviour of localized and extended waves. In the final part of this chapter we apply a constant electric field to the structure studied in the chapter 3, i.e., the cavity. We show in this case that, besides Bloch oscillations, electrons can be confined in certain regions only by inserting the nanotube in an electric field.

Tightening Quantum Speed Limits for Almost All States.

Science.gov (United States)

Campaioli, Francesco; Pollock, Felix A; Binder, Felix C; Modi, Kavan

2018-02-09

Conventional quantum speed limits perform poorly for mixed quantum states: They are generally not tight and often significantly underestimate the fastest possible evolution speed. To remedy this, for unitary driving, we derive two quantum speed limits that outperform the traditional bounds for almost all quantum states. Moreover, our bounds are significantly simpler to compute as well as experimentally more accessible. Our bounds have a clear geometric interpretation; they arise from the evaluation of the angle between generalized Bloch vectors.

Monsieur Philippe Galli Préfet de l’Ain France

CERN Multimedia

Maximilien Brice

2011-01-01

Photo 35: Le chef du département Physique P. Bloch, le porte-parole de la Collaboration CMS G. Tonelli,le Sous-Préfet de Gex O. Laurens-Bernard, le chef du département Technologie F. Bordry, le Péfet de l'Ain P. Galli et le Directeur-général R. Heuer. Photo 62: signature du livre d'or avec le Directeur de la recherche et de l'informatique S. Bertolucci.

Ambient Smell and the Retail Environment: Relating Olfaction Research to Consumer Behavior

OpenAIRE

Ward, Philippa; Davies, Barry; Kooijman, Dion

2004-01-01

This paper focuses on the use of ambient scent within retail environments, and investigates those mediating factors that help shape the emotional and behavioural responses that are stimulated. In doing so, it draws on the work of Mehrabian and Russell (1974), and attempts to contribute to the work on ambient scent in retailing by extending and elaborating the Gulas and Bloch (1995) model to encompass current research on human olfaction. The paper also introduces and specifically considers the...

Reciprocal mass tensor : a general form

International Nuclear Information System (INIS)

Roy, C.L.

1978-01-01

Using the results of earlier treatment of wave packets, a general form of reciprocal mass tensor has been obtained. The elements of this tensor are seen to be dependent on momentum as well as space coordinates of the particle under consideration. The conditions under which the tensor would reduce to the usual space-independent form, are discussed and the impact of the space-dependence of this tensor on the motion of Bloch electrons, is examined. (author)

The month of August - an Annales approach to the history of the Kowie: August 1881 to August 1914.

OpenAIRE

Hummel, H C

1985-01-01

• Opsomming: Die analities-historiese denkrigting in Frankryk, bekend as die Annalesskool, is deur Lucien Febvre en Marc Bloch tot stand gebring en meesterlik deur Fernand Braudel in sy klassieke werk oor die Middellandse Seegebied (1949) toegepas. Hierdie benadering geniet reeds wêreldwye aansien en navolging omdat dit die klem hoofsaaklik laat val op die soort geskiedenis wat nie op die tradisionele vlak of in gebaande weë lê nie. Gevolglik bied dit 'n uiters geskikte m...

Phase-space quantum mechanics study of two identical particles in an external oscillatory potential

Science.gov (United States)

Nieto, Luis M.; Gadella, Manuel

1993-01-01

This simple example is used to show how the formalism of Moyal works when it is applied to systems of identical particles. The symmetric and antisymmetric Moyal propagators are evaluated for this case; from them, the correct energy levels of energy are obtained, as well as the Wigner functions for the symmetric and antisymmetric states of the two identical particle system. Finally, the solution of the Bloch equation is straightforwardly obtained from the expressions of the Moyal propagators.

The Barkas effect and other higher-order Z1-contributions to the stopping power

International Nuclear Information System (INIS)

Andersen, H.H.

1985-01-01

The experimental evidence for contributions to the stopping power proportional to Z 1 3 (Barkas effect) and Z 1 4 (Bloch correction) at velocities around 10 v 0 is reviewed. Quantitative evidence is found for both terms but it is not possible experimentally to discern whether hard collisions contribute to the Barkas term. Evidence from single-collision events are drawn into the discussion and some experiments which may turn out to be decisive are discussed. (orig.)

Magnetization Transfer Effects on the Efficiency of Flow-driven Adiabatic Fast Passage Inversion of Arterial Blood

OpenAIRE

Hernandez-Garcia, Luis; Lewis, David P.; Moffat, Bradford; Branch, Craig A.

2007-01-01

Continuous arterial spin labeling experiments typically use flow-driven adiabatic fast passage (AFP) inversion of the arterial blood water protons. In this article, we measure the effect of magnetization transfer in blood and how it affects the inversion label. We use modified Bloch equations to model flow-driven adiabatic inversion in the presence of magnetization transfer in blood flowing at velocities from 1 to 30 cm/s in order to explain our findings. Magnetization transfer results in a r...

Electronic energy spectra in antiferromagnetic media with broken reciprocity

International Nuclear Information System (INIS)

Vitebsky, I.; Edelkind, J.; Bogachek, E.N.; Scherbakov, A.G.; Landman, U.

1997-01-01

Electronic energy spectra var-epsilon(q) of antiferromagnetically ordered media may display nonreciprocity; that is, the energies corresponding to Bloch states with wave numbers q and -q may be different. In this paper a simple Kronig-Penney model, which includes a staggered microscopic magnetic and electric fields of the proper symmetry, is employed to estimate the magnitude of nonreciprocity effects in systems such as antiferromagnetically ordered crystals as well as periodical layered structures. copyright 1997 The American Physical Society

Resilience to decoherence of the macroscopic quantum superpositions generated by universally covariant optimal quantum cloning

International Nuclear Information System (INIS)

Spagnolo, Nicolo; Sciarrino, Fabio; De Martini, Francesco

2010-01-01

We show that the quantum states generated by universal optimal quantum cloning of a single photon represent a universal set of quantum superpositions resilient to decoherence. We adopt the Bures distance as a tool to investigate the persistence of quantum coherence of these quantum states. According to this analysis, the process of universal cloning realizes a class of quantum superpositions that exhibits a covariance property in lossy configuration over the complete set of polarization states in the Bloch sphere.

Experimental and theoretical investigations of photocurrents in non-centrosymmetric semiconductor quantum wells

Energy Technology Data Exchange (ETDEWEB)

Duc, Huynh Thanh; Foerstner, Jens; Meier, Torsten [Department of Physics and CeOPP, University Paderborn (Germany); Priyadarshi, Shekar; Racu, Ana Maria; Pierz, Klaus; Siegner, Uwe; Bieler, Mark [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

2010-07-01

We compute photocurrents generated by femtosecond single-color laser pulses in non-centrosymmetric semiconductor quantum wells by combining a 14 x 14 k.p band structure theory with multi-band semiconductor Bloch equations. The transient photocurrents are investigated experimentally by measuring the associated Terahertz emission. The dependencies of the photocurrent and the Terahertz emission on the excitation conditions are discussed for (110)-oriented GaAs quantum wells. The comparison between theory and experiment shows a good agreement.

Hadronic total cross-sections through soft gluon summation in impact parameter space

International Nuclear Information System (INIS)

Grau, A.

1999-01-01

IThe Bloch-Nordsieck model for the parton distribution of hadrons in impact parameter space, constructed using soft gluon summation, is investigated in detail. Its dependence upon the infrared structure of the strong coupling constant α s is discussed, both for finite as well as singular, but integrable, α s . The formalism is applied to the prediction of total proton-proton and proton-antiproton cross-sections, where screening, due to soft gluon emission from the initial valence quarks, becomes evident

Propagation of complex shaped ultrafast pulses in highly optically dense samples

International Nuclear Information System (INIS)

Davis, J. C.; Fetterman, M. R.; Warren, W. S.; Goswami, D.

2008-01-01

We examine the propagation of shaped (amplitude- and frequency-modulated) ultrafast laser pulses through optically dense rubidium vapor. Pulse reshaping, stimulated emission dynamics, and residual electronic excitation all strongly depend on the laser pulse shape. For example, frequency swept pulses, which produce adiabatic passage in the optically thin limit (independent of the sign of the frequency sweep), behave unexpectedly in optically dense samples. Paraxial Maxwell optical Bloch equations can model our ultrafast pulse propagation results well and provide insight

Antimicrobial activity of different tissues of snakehead fish Channa striatus (Bloch

Directory of Open Access Journals (Sweden)

Pravin Kumar N

2012-05-01

Full Text Available Objective: The aim of this study was to identify the presence of antimicrobial activity in different organs/tissues (gills, blood, skin, liver, intestine, kidney, tissue and ovary extract of snakehead fish Channa striatus. Methods: A total of 48 fractions from the organs and tissue extracts were obtained by solid-phase extraction and the fractions were assayed for antimicrobial activity. The screening of antimicrobial activity for all the fractions were tested against 8 human pathogens including Gram positive (Methicillin-resistant Staphylococcus aureus (MRSA, Staphylococcus aureus, Bacillus cereus and Gram negative bacteria (Salmonella enteritidis, Shigella flexneri, Acinetobacter baumanni, Escherichia coli, Klebsiella pneumoniae using the British Society for Antimicrobial Chemotherapy (BSAC standardized disc susceptibility test method. The activity was measured in terms of zone of inhibition in mm. Results: The results indicated that, among the 8 organs/tissues tested only blood and gills extract fractions (40 and 60 % ACN fraction showed inhibition against Escherichia coli and 60 % ACN fraction of gill extract showed inhibition against Salmonella enteritidis. Protein profile analysis by SDS-PAGE showed that antimicrobial activity of the partially purified blood and gill tissue extracts might be due to low molecular weight peptides. Conclusions: The present study showed that, gill and blood extracts of Channa striatus can be a potential source of an antimicrobial protein for specific human pathogens.

Microbiological studies of irradiated dried mackerel (Cybium guttatum Bloch and Schnieder)

International Nuclear Information System (INIS)

Ahmed, M.; Joardar, S.K.; Bhuiya, A.D.; Islam, M.S.

1985-01-01

Microbiological studies of sun-dried mackerel fish, Cybium guttatum, were conducted by exposing the fish to doses of gamma-rays from 0.50 to 8.00 kGy at the storage temperatures of 10.20 and 30oC. The reduction of bacterial flora was determined both qualitatively and quantitatively. At 4 kGyone log cycle reduction of bacterial flora was achieved and at 8 kGy the reduction was nearly 2 log cycles. The irradiated samples were stored for two months and viable bacterial counts were taken. Except in a few cases, reduction in viable counts occurred. Bacterial isolates were made and both Mesophiles and Psychrophiles were identified. Micrococcus, Staphylococcus, Corymebacterium and some Bacillus were found to be the prominent groups in mesophiles, while Bacillus dominated in psychrophiles. Staphylococcus was found to be the most dominant bacterial flora in unirradiated samples, but they were highly affected by irradiation

Discontinuous Galerkin Approximations for Computing Electromagnetic Bloch Modes in Photonic Crystals

NARCIS (Netherlands)

Lu, Zhongjie; Cesmelioglu, A.; van der Vegt, Jacobus J.W.; Xu, Yan

We analyze discontinuous Galerkin finite element discretizations of the Maxwell equations with periodic coefficients. These equations are used to model the behavior of light in photonic crystals, which are materials containing a spatially periodic variation of the refractive index commensurate with

Finding of triploid Carassius Gibelio (Bloch, 1780)(Cypriniformes, Cyprinidae), in Turkey

Czech Academy of Sciences Publication Activity Database

Kalous, Lukáš; Memis, D.; Bohlen, Jörg

2004-01-01

Roč. 28, č. 1 (2004), s. 77-79 ISSN 0399-0974 R&D Projects: GA ČR GA523/02/0460 Institutional research plan: CEZ:AV0Z5045916 Keywords : carassius gibelio * cyprinidae * Turkey Subject RIV: ED - Physiology Impact factor: 0.312, year: 2004

Wannier-Bloch approach to localization in high-harmonics generation in solids

Czech Academy of Sciences Publication Activity Database

Osika, E.N.; Chacon, A.; Ortmann, L.; Suarez, N.; Perez-Hernandez, J.A.; Szafran, B.; Ciappina, Marcelo F.; Sols, F.; Landsman, A.S.; Lewenstein, M.

2017-01-01

Roč. 7, č. 2 (2017), 1-14, č. článku 021017. ISSN 2160-3308 R&D Projects: GA MŠk EF15_008/0000162; GA MŠk LQ1606 EU Projects: European Commission(XE) 654148 - LASERLAB-EUROPE Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 Keywords : field * photoemission * spectroscopy * ionization Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 12.789, year: 2016

Positronium bloch function, and trapping of positronium in vacancies, in ice

International Nuclear Information System (INIS)

Mogensen, O.E.; Eldrup, M.

1977-08-01

Positron annihilation techniques were used to study the behaviour of positronium (Ps) in pure light and heavy ice in the temperature interval -185 2 was extracted by very detailed computer analyses. A nearly-free-Ps theory, including phonon influence, could not explain the temperature dependence of /Asub(g vector)/ 2 . The Ps trapping in vacancies could not be explained in detail in terms of several models, including the simple 'trapping model'. A main difficulty was the fact that para-Ps and ortho-Ps are trapped at roughly the same amount at a certain vacancy concentration. Our results imply a high (several ppm) vacancy concentration at the melting point in ice in agreement with other independent estimates. This fact might introduce pronounced changes in currently accepted theories of the electrical properties of ice. (author)

Dynamical corrections to density-functional theory for quasiparticles in ferromagnetic 4f systems. I. T = 0 results for EuO

International Nuclear Information System (INIS)

Nolting, W.; Borstel, G.; Borgiel, W.

1987-01-01

A theory for the electronic quasiparticle spectrum of ferromagnetic 4f systems is presented and applied to the semiconductor EuO. The starting point is a d-f exchange model, which we solve exactly for T = 0. One of the results is a simple relationship between the spin-up quasiparticle energies and the ''free'' Bloch energies epsilon-c/sub m/(k), which we use to fix the epsilon-c/sub m/(k) in a highly realistic manner by performing a new self-consistent spin-polarized band-structure calculation based on density-functional theory. With the so-determined Bloch energies we investigate the spin-down quasiparticle spectrum, which exhibits even at T = 0 strong many-body effects as a consequence of spin-exchange processes between localized magnetic 4f moments and itinerant conduction electrons. We discuss in detail the spin-down quasiparticle spectral density for the ΓL direction, which should be observable in an inverse photoemission experiment. The shape of this function is strongly k dependent, revealing different types of quasiparticles. The prominent quasiparticle peaks in the spin-down quasiparticle spectral density are used to construct a quasiparticle band structure, which shows some striking deviations from the one-particle solution of the density-functional theory. Furthermore, results for the electronic self-energy and the quasiparticle density of states are presented

Beam profiles for fast neutrons; and reply

International Nuclear Information System (INIS)

Bewley, D.K.; Parnell, C.J.; Bloch, P.

1976-01-01

The authors express surprise that Bloch et al. (Bloch, P.H., Hendry, G.O., Hilton, J.L., Quam, W.M., Reinhard, D.K., and Wilson, C., 1976, Phys. Med. Biol., Vol. 21, 450) justified a target size of 5.5 x 5.5 cm in a neutron generator by comparison with the profile given by a 2.5 MV X-ray generator. The penumbral width of this new neutron generator is more than twice that of a modern megavoltage X-ray machine, and larger than those of beams from standard 60 Co units, or of the Hammersmith Hospital cyclotron beam. The large target size of the neutron generator may have to be accepted as a necessary evil, but should not be considered satisfactory. In reply, one of the authors of the original note presents the results of calculations of beam profiles for 14 MeV neutron beams in a tissue-equivalent phantom, and suggests that the broader profiles are principally caused by the larger probability of side scatter, not by source size. The most fruitful approach to sharpening the neutron beam profile would seem to be to design a field flattening filter to increase relative dose near the edge inside the geometrically defined field. Calculations indicating that Bewley and Parnell have underestimated the penumbral widths of 60 Co beams are also presented. (U.K.)

A quick and easy test for deciding entanglement status of an N-qubit pure quantum state

International Nuclear Information System (INIS)

Mehendale, D.P.; Joag, P.S.

2018-01-01

We develop a simple criterion in terms of a necessary-sufficient condition (NS condition) for deciding separability of an arbitrary n-qubit pure quantum state. This NS condition provides a quick and easy test procedure to determine the entanglement status of a pure quantum state. We normalize the given quantum state and using this normalized state we can easily build a simplest system of equations containing trigonometric functions by making use of the well known Bloch Sphere representation for single qubit states and check whether or not this system of equations is consistent. According to proposed NS condition the given pure quantum state is separable (entangled) if and only if the above mentioned system of equations is consistent (inconsistent). We build this system of equations by equating the coefficients of computational basis states in the superposition representing the given pure quantum state with certain products of trigonometric functions obtained using standard Bloch Sphere representation for single qubit states. To establish separability of given state one requires to find a valid solution of the above mentioned system of equations but entanglement on the other hand follows when any two equations in this system of equations are mutually inconsistent. Thus, entanglement of the state can follow easily if one succeeds in finding any two mutually inconsistent equations in the above mentioned system of equations.

Ultrawide low frequency band gap of phononic crystal in nacreous composite material

International Nuclear Information System (INIS)

Yin, J.; Huang, J.; Zhang, S.; Zhang, H.W.; Chen, B.S.

2014-01-01

The band structure of a nacreous composite material is studied by two proposed models, where an ultrawide low frequency band gap is observed. The first model (tension-shear chain model) with two phases including brick and mortar is investigated to describe the wave propagation in the nacreous composite material, and the dispersion relation is calculated by transfer matrix method and Bloch theorem. The results show that the frequency ranges of the pass bands are quite narrow, because a special tension-shear chain motion in the nacreous composite material is formed by some very slow modes. Furthermore, the second model (two-dimensional finite element model) is presented to investigate its band gap by a multi-level substructure scheme. Our findings will be of great value to the design and synthesis of vibration isolation materials in a wide and low frequency range. Finally, the transmission characteristics are calculated to verify the results. - Highlights: • A Brick-and-Mortar structure is used to discuss wave propagation through nacreous materials. • A 1D Bloch wave solution of nacreous materials with a tension-shear chain model is obtained. • The band structure and transmission characteristics of nacreous materials with the FE model are examined. • An ultrawide low frequency band gap is found in nacreous materials with both theory and FE model

Group Theory of Wannier Functions Providing the Basis for a Deeper Understanding of Magnetism and Superconductivity

Directory of Open Access Journals (Sweden)

Ekkehard Krüger

2015-05-01

Full Text Available The paper presents the group theory of optimally-localized and symmetry-adapted Wannier functions in a crystal of any given space group G or magnetic group M. Provided that the calculated band structure of the considered material is given and that the symmetry of the Bloch functions at all of the points of symmetry in the Brillouin zone is known, the paper details whether or not the Bloch functions of particular energy bands can be unitarily transformed into optimally-localized Wannier functions symmetry-adapted to the space group G, to the magnetic group M or to a subgroup of G or M. In this context, the paper considers usual, as well as spin-dependent Wannier functions, the latter representing the most general definition of Wannier functions. The presented group theory is a review of the theory published by one of the authors (Ekkehard Krüger in several former papers and is independent of any physical model of magnetism or superconductivity. However, it is suggested to interpret the special symmetry of the optimally-localized Wannier functions in the framework of a nonadiabatic extension of the Heisenberg model, the nonadiabatic Heisenberg model. On the basis of the symmetry of the Wannier functions, this model of strongly-correlated localized electrons makes clear predictions of whether or not the system can possess superconducting or magnetic eigenstates.

Semiclassical methods in solid state physics : two examples

Science.gov (United States)

Bellissard, Jean; Barelli, Armelle

1993-02-01

We present here a review of two problems motivated by 2D models for high T, superconductivity. The first part concerns the energy spectrum of 2D Bloch electrons in a uniform magnetic field. A semiclassical analysis provides a qualitative as well as a quantitative understanding of this spectrum. In the second part we make the case for the application of “Quantum Chaos" to strongly correlated fermion systems. It is illustrated by the level spacing distribution for the t - J model in two dimensions. Ce travail est une revue de deux problèmes motivés par l'étude des modèles bidimensionnels pour la supraconductivité à haute température critique. La première partie concerne l'étude du spectre d'énergie pour des électrons de Bloch bidimensionnels soumis à un champ magnétique uniforme. Une analyse semi-classique permet d'en comprendre les propriétés qualitatives et quantitatives. La deuxième partie est un plaidoyer pour l'utilisation des méthodes du “Chaos Quantique" dans l'étude des systèmes de fermions fortement corrélés. La distribution des écarts de niveaux d'un modèle t - J en deux dimensions, en fournit une illustration.

Improving the time efficiency of the Fourier synthesis method for slice selection in magnetic resonance imaging.

Science.gov (United States)

Tahayori, B; Khaneja, N; Johnston, L A; Farrell, P M; Mareels, I M Y

2016-01-01

The design of slice selective pulses for magnetic resonance imaging can be cast as an optimal control problem. The Fourier synthesis method is an existing approach to solve these optimal control problems. In this method the gradient field as well as the excitation field are switched rapidly and their amplitudes are calculated based on a Fourier series expansion. Here, we provide a novel insight into the Fourier synthesis method via representing the Bloch equation in spherical coordinates. Based on the spherical Bloch equation, we propose an alternative sequence of pulses that can be used for slice selection which is more time efficient compared to the original method. Simulation results demonstrate that while the performance of both methods is approximately the same, the required time for the proposed sequence of pulses is half of the original sequence of pulses. Furthermore, the slice selectivity of both sequences of pulses changes with radio frequency field inhomogeneities in a similar way. We also introduce a measure, referred to as gradient complexity, to compare the performance of both sequences of pulses. This measure indicates that for a desired level of uniformity in the excited slice, the gradient complexity for the proposed sequence of pulses is less than the original sequence. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Dynamical renormalization group approach to relaxation in quantum field theory

International Nuclear Information System (INIS)

Boyanovsky, D.; Vega, H.J. de

2003-01-01

The real time evolution and relaxation of expectation values of quantum fields and of quantum states are computed as initial value problems by implementing the dynamical renormalization group (DRG). Linear response is invoked to set up the renormalized initial value problem to study the dynamics of the expectation value of quantum fields. The perturbative solution of the equations of motion for the field expectation values of quantum fields as well as the evolution of quantum states features secular terms, namely terms that grow in time and invalidate the perturbative expansion for late times. The DRG provides a consistent framework to resum these secular terms and yields a uniform asymptotic expansion at long times. Several relevant cases are studied in detail, including those of threshold infrared divergences which appear in gauge theories at finite temperature and lead to anomalous relaxation. In these cases the DRG is shown to provide a resummation akin to Bloch-Nordsieck but directly in real time and that goes beyond the scope of Bloch-Nordsieck and Dyson resummations. The nature of the resummation program is discussed in several examples. The DRG provides a framework that is consistent, systematic, and easy to implement to study the non-equilibrium relaxational dynamics directly in real time that does not rely on the concept of quasiparticle widths

Experimental demonstration of a Hadamard gate for coherent state qubits

DEFF Research Database (Denmark)

Tipsmark, Anders; Dong, Ruifang; Laghaout, Amine

2011-01-01

We discuss and make an experimental test of a probabilistic Hadamard gate for coherent state qubits. The scheme is based on linear optical components, nonclassical resources, and the joint projective action of a photon counter and a homodyne detector. We experimentally characterize the gate for t...... for the coherent states of the computational basis by full tomographic reconstruction of the transformed output states. Based on the parameters of the experiment, we simulate the fidelity for all coherent state qubits on the Bloch sphere....

Experimental demonstration of a Hadamard gate for coherent state qubits

Energy Technology Data Exchange (ETDEWEB)

Tipsmark, Anders; Laghaout, Amine; Andersen, Ulrik L. [Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby (Denmark); Dong, Ruifang [Quantum Frequency Standards Division, National Time Service Center (NTSC), Chinese Academy of Sciences, 710600 Lintong, Shaanxi (China); Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby (Denmark); Marek, Petr [Department of Optics, Palacky University, 17. listopadu 12, CZ-77146 Olomouc (Czech Republic); Jezek, Miroslav [Department of Optics, Palacky University, 17. listopadu 12, CZ-77146 Olomouc (Czech Republic); Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby (Denmark)

2011-11-15

We discuss and make an experimental test of a probabilistic Hadamard gate for coherent state qubits. The scheme is based on linear optical components, nonclassical resources, and the joint projective action of a photon counter and a homodyne detector. We experimentally characterize the gate for the coherent states of the computational basis by full tomographic reconstruction of the transformed output states. Based on the parameters of the experiment, we simulate the fidelity for all coherent state qubits on the Bloch sphere.

Is quark-antiquark annihilation infrared safe at high energy

International Nuclear Information System (INIS)

Frenkel, J.; Gatheral, J.G.M.; Taylor, J.C.

1983-01-01

In perturbative QCD, the Bloch-Nordsieck cross section for quark-antiquark annihilation is known, to order g 4 , to be infrared finite, except for terms which are power suppressed at high energies. A fairly simple explanation of this fact, using analyticity, unitarity and an analysis of mass-singularities in both Feynman and axial gauges, is given. The argument applies fairly easily to order g 6 . Assuming a generalized unitarity principle, the argument can be extended to all orders. (Author) [pt

Univalent Functions in the Möbius Invariant QK Space

Directory of Open Access Journals (Sweden)

Fernando Pérez-González

2011-01-01

Full Text Available It is shown that a univalent function f belongs to QK if and only if sup a∈∫01M∞2(r,f∘φa-f(aK′(log (1/rdr<∞, where φa(z=(a-z/(1-a¯z, provided K satisfies certain regularity conditions. It is also shown that under these conditions QK contains all univalent Bloch functions if and only if ∫01(log ((1+r/(1-r2K′(log (1/rdr<∞.

Time-dependent screening of a positive charge distribution in metals: Excitons on an ultra-short time scale

OpenAIRE

Schöne, Wolf-Dieter; Ekardt, Walter

2000-01-01

Experiments determining the lifetime of excited electrons in crystalline copper reveal states which cannot be interpreted as Bloch states [S. Ogawa {\\it et al.}, Phys. Rev. B {\\bf 55}, 10869 (1997)]. In this article we propose a model which explains these states as transient excitonic states in metals. The physical background of transient excitons is the finite time a system needs to react to an external perturbation, in other words, the time which is needed to build up a polarization cloud. ...

Bose-Einstein condensates in optical lattices: Band-gap structure and solitons

International Nuclear Information System (INIS)

Louis, Pearl J. Y.; Kivshar, Yuri S.; Ostrovskaya, Elena A.; Savage, Craig M.

2003-01-01

We analyze the existence and stability of spatially extended (Bloch-type) and localized states of a Bose-Einstein condensate loaded into an optical lattice. In the framework of the Gross-Pitaevskii equation with a periodic potential, we study the band-gap structure of the matter-wave spectrum in both the linear and nonlinear regimes. We demonstrate the existence of families of spatially localized matter-wave gap solitons, and analyze their stability in different band gaps, for both repulsive and attractive atomic interactions

Approximate representations of propagators in an external field

International Nuclear Information System (INIS)

Fried, H.M.

1979-01-01

A method of forming approximate representations for propagators with external field dependence is suggested and discussed in the context of potential scattering. An integro-differential equation in D+1 variables, where D represents the dimensionality of Euclidian space-time, is replaced by a Volterra equation in one variable. Approximate solutions to the latter provide a generalization of the Bloch-Nordsieck representation, containing the effects of all powers of hard-potential interactions, each modified by a characteristic soft-potential dependence [fr

A wave propagation matrix method in semiclassical theory

International Nuclear Information System (INIS)

Lee, S.Y.; Takigawa, N.

1977-05-01

A wave propagation matrix method is used to derive the semiclassical formulae of the multiturning point problem. A phase shift matrix and a barrier transformation matrix are introduced to describe the processes of a particle travelling through a potential well and crossing a potential barrier respectively. The wave propagation matrix is given by the products of phase shift matrices and barrier transformation matrices. The method to study scattering by surface transparent potentials and the Bloch wave in solids is then applied

Local orbitals approach to the anomalous Hall and Nernst effects in itinerant ferromagnets

Directory of Open Access Journals (Sweden)

Středa Pavel

2014-07-01

Full Text Available Linear response of the orbital momentum to the gradient of the chemical potential is used to obtain anomalous Hall conductivity. Transition from the ideal Bloch system for which the conductivity is determined by the Berry phase curvatures to the case of strong disorder for which the conductivity becomes dependent on the relaxation time is analysed. Presented tight-binding model reproduces experimentally observed qualitative features of the anomalous Hall conductivity and the transverse Peltier coefficient in the so called bad-metal and scattering-independent regimes.

Spermatological characters of monozoic tapeworms (Cestoda: Caryophyllidea), including first data on a species from the Indomalayan catfish

Czech Academy of Sciences Publication Activity Database

Yoneva, A.; Levron, Céline; Ash, Anirban; Scholz, Tomáš

2012-01-01

Roč. 98, č. 2 (2012), s. 423-430 ISSN 0022-3395 R&D Projects: GA ČR GA524/08/0885; GA ČR GD206/09/H026; GA ČR GAP506/10/1994; GA ČR GBP505/12/G112 Institutional research plan: CEZ:AV0Z60220518 Keywords : GLARIDACRIS-CATOSTOMI COOPER * WENYONIA-VIRILIS WOODLAND * EUBOTHRIUM-CRASSUM BLOCH * SPERM ULTRASTRUCTURE * SPERMIOGENESIS * PLATYHELMINTHES * SPERMATOZOA * EUCESTODA * SPERMATOGENESIS * PHYLOGENY Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.321, year: 2012

Observaton of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides

DEFF Research Database (Denmark)

Ha, Sangwoo; Sukhorukov, Andrey A.; Lavrinenko, Andrei

2011-01-01

We report the experimental observation of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides shifted longitudinally by half of modulation period. According to the symmetry analysis, such a coupler supports two electromagnetic modes with exactly matched slow or fast...... group velocities but different phase velocities for frequencies close to the edge of the photonic band. We confirm the predicted properties of the modes by directly extracting their dispersion and group velocities from the near-field measurements using specialized Bloch-wave spectral analysis method....