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## Photophysical characterization of the plant growth regulator 2-(1-naphthyl) acetamide

Silva, Eliana Sousa Da; Wong-Wah-Chung, Pascal; Sarakha, Mohamed; Burrows, Hugh D.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.285747%
The photophysical properties of the widely used plant growth regulator 2-(1-naphthyl) acetamide (NAD) were studied in water and representative organic solvents (ethanol, ethylene glycol, acetonitrile, chloroform, 1,4-dioxane) employing steady-state and time-resolved spectroscopy. Quantum yields and lifetimes of fluorescence, phosphorescence and triplet formation and triplet–triplet absorption spectra were obtained. From these, all radiative and radiationless rate constants have been determined, together with singlet and triplet excited state energies (4.00 and 2.69 eV, respectively). The fluorescence quantum yield and lifetime increased on going from water (ΦF 0.066, τF 35.0 ns) to non-hydrogen bonding solvents (ΦF 0.357, τF 51.0 ns in 1,4-dioxane), probably due to decreased internal conversion. Fluorescence was quenched by several anions through an electron transfer process. A limit on the reduction potential of 1NAD* of E0 2.1 ± 0.2 V was estimated. The attribution of the transient absorption seen in nanosecond laser flash photolysis to 3NAD* was confirmed by energy transfer and oxygen quenching. Quenching of triplet states leads to singlet oxygen formation, with quantum yields varying from 0.097 in water to 0.396 in chloroform. However...

## The 2:1 cycloadducts from [3+2] 1,3-dipolar cycloaddition of nitrile oxide and vinylacetic acid. Synthesis and liquid crystal behaviour

Tavares, Aline; Vilela, Guilherme D.; Toldo, Josene; Goncalves, Paulo F. B.; Eccher, Juliana; Bechtold, Ivan H.; Sampaio, Anderson R.; Viscovini, Ronaldo C.; Schneider, Paulo H.; Merlo, Aloir A.
Fonte: TAYLOR & FRANCIS LTD; ABINGDON Publicador: TAYLOR & FRANCIS LTD; ABINGDON
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.656953%
Four liquid crystals (LC) 3,7a-bis(4-alkyloxyphenyl)-7,7a-dihydro-6H-isoxazolo[2,3-d][1,2,4]oxadiazol-6-yl)acetic acid (7a-d) were synthesised and the mesomorphic behaviour reported. The LCs were characterised as 2: 1 bisadducts, which were obtained from a double [3+2] 1,3-dipolar cycloaddition. In the first step, the cycloaddition of 4-alkyloxyphenylnitrile oxide (4a-d) and vinylacetic acid (5) gave the initial unobserved 1:1 cycloadducts 2-[3-(4-alkyloxyphenyl)-4,5-dihydroisoxazol-5-yl]acetic acid (6a-d). In the second step, the addition of a second equivalent of 4 to 6 yielded the 2: 1 bisadducts 7a-d without any traces of 6. All compounds 7a-d were unstable during the transition from the mesophase to the isotropic state upon first heating as evidenced by the large peaks in the differential scanning calorimetry traces. Due to the chemical instability of the compounds upon heating, the transition temperature related to the smectic C to smectic A transitions was acquired by means of an image processing method. X-Ray diffraction experiments were also used to analyse the liquid-crystalline phases. A theoretical calculation was performed using density functional theory (DFT) methods at the PBE1PBE/6-311+G(2d,p) level (with solvent effect) in order to get information about the energetic profile of the 2: 1 cycloaddition. DFT studies revealed that the cycloaddition process is controlled by the HOMO(dipolarophile) - LUMO(1...

## A new spin-2 self-dual model in D=2+1

Dalmazi, D.; Mendonca, Elias L.
Tipo: Artigo de Revista Científica Formato: 14
Português
Relevância na Pesquisa
76.47011%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); There are three self-dual models of massive particles of helicity + 2 (or -2) in D = 2 + 1. Each model is of first, second, and third-order in derivatives. Here we derive a new self-dual model of fourth-order, L(SD)((4)), which follows from the third-order model (linearized topologically massive gravity) via Noether embedment of the linearized Weyl symmetry. In fact, each self-dual model can be obtained from the previous one L(SD)((i)) -> L(SD)((i+1)), i = 1, 2, 3 by the Noether embedment of an appropriate gauge symmetry, culminating in L(SD)((4)). The new model may be identified with the linearized version of L(HDTMG) = epsilon(mu nu rho)Gamma(epsilon)(mu gamma) [partial derivative(nu)Gamma(gamma)(epsilon rho) + (2/3)Gamma(gamma)(nu delta)Gamma(delta)(rho epsilon)]/8m + root-g[R(mu nu)R(nu mu) - 3R(2)/8]/2m(2). We also construct a master action relating the third-order self-dual model to L(SD)((4)) by means of a mixing term with no particle content which assures spectrum equivalence of L(SD)((4)) to other lower-order self-dual models despite its pure higher derivative nature and the absence of the Einstein-Hilbert action. The relevant degrees of freedom of L(SD)((4)) are encoded in a rank-two tensor which is symmetric...

## Dual descriptions of spin-two massive particles in D=2+1 via master actions

Dalmazi, D.; Mendonca, Elias L.
Fonte: Amer Physical Soc Publicador: Amer Physical Soc
Tipo: Artigo de Revista Científica Formato: 7
Português
Relevância na Pesquisa
76.5001%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 06/59563-0; In the first part of this work we show the decoupling (up to contact terms) of redundant degrees of freedom which appear in the covariant description of spin-two massive particles in D=2+1. We make use of a master action which interpolates, without solving any constraints, between a first-, second-, and third-order (in derivatives) self-dual model. An explicit dual map between those models is derived. In our approach the absence of ghosts in the third-order self-dual model, which corresponds to a quadratic truncation of topologically massive gravity, is due to the triviality (no particle content) of the Einstein-Hilbert action in D=2+1. In the second part of the work, also in D=2+1, we prove the quantum equivalence of the gauge invariant sector of a couple of self-dual models of opposite helicities (+2 and -2) and masses m(+) and m(-) to a generalized self-dual model which contains a quadratic Einstein-Hilbert action, a Chern-Simons term of first order, and a Fierz-Pauli mass term. The use of a first-order Chern-Simons term instead of a third-order one avoids conflicts with the sign of the Einstein-Hilbert action.

## Duality of parity doublets of helicity +/- 2 in D=2+1 dimensions

Dalmazi, D.; Mendonca, Elias L.
Fonte: Amer Physical Soc Publicador: Amer Physical Soc
Tipo: Artigo de Revista Científica Formato: 8
Português
Relevância na Pesquisa
76.434585%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); In D = 2 + 1 dimensions there are two dual descriptions of parity singlets of helicity +/-1, namely, the self-dual model of first order (in derivatives) and the Maxwell-Chern-Simons theory of second order. Correspondingly, for helicity +/-2 there are four models S-SD+/-((r)) describing parity singlets of helicities +/-2. They are of first, second, third, and fourth order (r = 1, 2, 3, 4), respectively. Here we show that the generalized soldering of the opposite helicity models S-SD+((4)) and S-SD-((4)) leads to the linearized form of the new massive gravity suggested by Bergshoeff, Hohm, and Townsend (BHT) similarly to the soldering of S-SD+((3)) and S-SD-((3)). We argue why in both cases we have the same result. We also find out a triple master action which interpolates between the three dual models: linearized BHT theory, S-SD+((3)) + S-SD-((3)), and S-SD+((4)) + S-SD-((4)). By comparing gauge invariant correlation functions we deduce dual maps between those models. In particular, we learn how to decompose the field of the linearized BHT theory in helicity eigenstates of the dual models up to gauge transformations.

## Unitarity of spin-2 theories with linearized Weyl symmetry in D=2+1 dimensions

Dalmazi, D.
Fonte: Amer Physical Soc Publicador: Amer Physical Soc
Tipo: Artigo de Revista Científica Formato: 6
Português
Relevância na Pesquisa
76.42553%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Here we prove unitarity of the recently found fourth-order (in derivatives) self-dual model of spin-2 by investigating the analytic structure of its propagator. The model describes massive particles of helicity +2 (or -2) in D = 2 + 1 dimensions and corresponds to the quadratic truncation of a higher derivative topologically massive gravity about a flat background. It is an intriguing example of a theory where a term in the propagator of the form 1/[square(2)(square - m(2))] does not lead to ghosts. The crucial role of the linearized Weyl symmetry in getting rid of the ghosts is pointed out. We use a peculiar pair of gauge conditions which fix the linearized reparametrizations and linearized Weyl symmetries separately.

## Generalized soldering of +/- 2 helicity states in D=2+1

Dalmazi, D.; Mendonca, Elias L.
Fonte: Amer Physical Soc Publicador: Amer Physical Soc
Tipo: Artigo de Revista Científica Formato: 7
Português
Relevância na Pesquisa
76.403906%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The direct sum of a couple of Maxwell-Chern-Simons gauge theories of opposite helicities +/- 1 does not lead to a Proca theory in D=2+1, although both theories share the same spectrum. However, it is known that by adding an interference term between both helicities we can join the complementary pieces together and obtain the physically expected result. A generalized soldering procedure can be defined to generate the missing interference term. Here, we show that the same procedure can be applied to join together +/- 2 helicity states in a full off-shell manner. In particular, by using second-order (in derivatives) self-dual models of helicities +/- 2 (spin-2 analogues of Maxwell-Chern-Simmons models) the Fierz-Pauli theory is obtained after soldering. Remarkably, if we replace the second-order models by third-order self-dual models (linearized topologically massive gravity) of opposite helicities, after soldering, we end up exactly with the new massive gravity theory of Bergshoeff, Hohm, and Townsend in its linearized approximation.

## MÉTODO ALTERNATIVO PARA A SÍNTESE E MECANISMO DE 2-(1,3-DITIANO-2-ILIDENO)-ACETONITRILA

Ferreira,Marcelle S.; Figueroa-Villar,José D.
Tipo: Artigo de Revista Científica Formato: text/html
Relevância na Pesquisa
76.27158%
We report an alternative method for the synthesis of 2-(1,3-dithian-2-ylidene)-acetonitrile using 3-(4-chlorophenyl)-3-oxopropanenitrile and carbon disulfide as starting materials. The methanolysis of the intermediate 3-(4-chlorophenyl)-2-(1,3-dithian-2-ylidene)-3-oxopropanenitrile occurs via three possible intermediates, leading to the formation of the product at a 75% overall yield. Molecular modeling simulation of the reaction pathway using B3LYP 6-311G++(2df,2p) justified the proposed reaction mechanism.

## Dual descriptions of massive spin-3 particles in D=2+1 via Noether gauge embedment

Mendonca, E. L.; Dalmazi, D.
Fonte: Amer Physical Soc Publicador: Amer Physical Soc
Tipo: Artigo de Revista Científica Formato: 1-9
Português
Relevância na Pesquisa
76.363525%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); We present here a relationship among massive self-dual models for spin-3 particles in D = 2 + 1 via the Noether gauge embedment (NGE) procedure. Starting with a first-order model (in derivatives) S-SD(1) we have obtained a sequence of four self-dual models S-SD(i) where i = 1; 2; 3; 4. We demonstrate that the NGE procedure generates the correct action for the auxiliary fields automatically. We obtain the whole action for the fourth-order self-dual model including all the needed auxiliary fields to get rid of the ghosts of the theory.

## Delta inulin: a novel, immunologically active, stable packing structure comprising β-d-[2 → 1] poly(fructo-furanosyl) α-d-glucose polymers

Cooper, Peter D; Petrovsky, Nikolai
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.29522%
We report a novel isoform of β-d-[2 → 1] poly(fructo-furanosyl) α-d-glucose termed delta inulin (DI), comparing it with previously described alpha (AI), beta (BI) and gamma (GI) isoforms. In vitro, DI is the most immunologically active weight/weight in human complement activation and in binding to monocytes and regulating their chemokine production and cell surface protein expression. In vivo, this translates into potent immune adjuvant activity, enhancing humoral and cellular responses against co-administered antigens. As a biocompatible polysaccharide particle, DI is safe and well tolerated by subcutaneous or intramuscular injection. Physico-chemically, DI forms as an insoluble precipitate from an aqueous solution of suitable AI, BI or GI held at 37–48°C, whereas the precipitate from the same solution at lower temperatures has the properties of AI or GI. DI can also be produced by heat conversion of GI suspensions at 56°C, whereas GI is converted from AI at 45°C. DI is distinguished from GI by its higher temperature of solution in dilute aqueous suspension and by its lower solubility in dimethyl sulfoxide, both consistent with greater hydrogen bonding in DI's polymer packing structure. DI suspensions can be dissolved by heat...

## Dual descriptions of spin two massive particles in $D=2+1$ via master actions

Dalmazi, D.; Mendonca, Elias L.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.5001%
In the first part of this work we show the decoupling (up to contact terms) of redundant degrees of freedom which appear in the covariant description of spin two massive particles in $D=2+1$. We make use of a master action which interpolates, without solving any constraints, between a first, second and third order (in derivatives) self-dual model. An explicit dual map between those models is derived. In our approach the absence of ghosts in the third order self-dual model, which corresponds to a quadratic truncation of topologically massive gravity, is due to the triviality (no particle content) of the Einstein-Hilbert action in $D=2+1$. In the second part of the work, also in $D=2+1$, we prove the quantum equivalence of the gauge invariant sector of a couple of self-dual models of opposite helicities (+2 and -2) and masses $m_+$ and $m_-$ to a generalized self-dual model which contains a quadratic Einstein-Hilbert action, a Chern-Simons term of first order and a Fierz-Pauli mass term. The use of a first order Chern-Simons term instead of a third order one avoids conflicts with the sign of the Einstein-Hilbert action.; Comment: title and abstract slightly modified, 3 references added, comments on interactions included

## Duality of parity doublets of helicity $\pm 2$ in $D=2+1$

Dalmazi, D.; Mendonça, Elias L.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
76.434585%
In $D=2+1$ dimensions there are two dual descriptions of parity singlets of helicity $\pm 1$, namely the self-dual model of first-order (in derivatives) and the Maxwell-Chern-Simons theory of second-order. Correspondingly, for helicity $\pm 2$ there are four models $S_{SD\pm}^{(r)}$ describing parity singlets of helicities $\pm 2$. They are of first-, second-,third- and fourth-order ($r=1,2,3,4$) respectively. Here we show that the generalized soldering of the opposite helicity models $S_{SD+}^{(4)}$ and $S_{SD-}^{(4)}$ leads to the linearized form of the new massive gravity suggested by Bergshoeff, Hohm and Townsend (BHT) similarly to the soldering of $S_{SD+}^{(3)}$ and $S_{SD-}^{(3)}$. We argue why in both cases we have the same result. We also find out a triple master action which interpolates between the three dual models: linearized BHT theory, $S_{SD+}^{(3)} + S_{SD-}^{(3)}$ and $S_{SD+}^{(4)} + S_{SD-}^{(4)}$. By comparing gauge invariant correlation functions we deduce dual maps between those models. In particular, we learn how to decompose the field of the linearized BHT theory in helicity eigenstates of the dual models up to gauge transformations.; Comment: 15 pages, no figures

## Generalised scalar particle quantisation in 1+1 dimensions and $D(2,1;\alpha)$

Corney, S P; Jarvis, P D; Tsohantjis, I; McAnally, D S
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
76.478374%
The exceptional superalgebra $\D21a$ has been classified as a candidate conformal supersymmetry algera in two dimensions. We propose an alternative interpretation of it as an extended BFV-BRST quantisation superalgebra in 2D ($D(2,1;1) \simeq osp(2,2|2)$). A superfield realization is presented wherein the standard extended phase space coordinates can be identified. The physical states are studied via the cohomology of the BRST operator. Finally we reverse engineer a classical action corresponding to the algebraic model we have constructed, and identify the Lagrangian equations of motion.; Comment: 16 pages, no figures

## Unitarity of spin-2 theories with linearized Weyl symmetry in $D=2+1$

Dalmazi, D.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
76.42553%
Here we prove unitarity of the recently found fourth-order self-dual model of spin-2 by investigating the analytic structure of its propagator. The model describes massive particles of helicity +2 (or -2) in $D=2+1$ and corresponds to the quadratic truncation of a higher derivative topologically massive gravity about a flat background. It is an intriguing example of a theory where a term in the propagator of the form $1/\lbrack\Box^2 (\Box - m^2)\rbrack$ does not lead to ghosts. The crucial role of the linearized Weyl symmetry in getting rid of the ghosts is pointed out. We use a peculiar pair of gauge conditions which fix the linearized reparametrizations and linearized Weyl symmetries separetely.; Comment: 9 pages, no figures

## A study of the gauge invariant, nonlocal mass operator $Tr \int d^4x F_{\mu\nu}(D^2)^{-1} F_{\mu\nu}$ in Yang-Mills theories

Capri, M. A. L.; Dudal, D.; Gracey, J. A.; Lemes, V. E. R.; Sobreiro, R. F.; Sorella, S. P.; Verschelde, H.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.43192%
The nonlocal mass operator $Tr \int d^4x F_{\mu\nu} (D^2)^{-1} F_{\mu\nu}$ is considered in Yang-Mills theories in Euclidean space-time. It is shown that the operator $Tr \int d^4x F_{\mu\nu} (D^2)^{-1} F_{\mu\nu}$ can be cast in local form through the introduction of a set of additional fields. A local and polynomial action is thus identified. Its multiplicative renormalizability is proven by means of the algebraic renormalization in the class of linear covariant gauges. The anomalous dimensions of the fields and of the mass operator are computed at one loop order. A few remarks on the possible role of this operator for the issue of the gauge invariance of the dimension two condensates are outlined.; Comment: 34 pages

## Generalized soldering of $\pm 2$ helicity states in $D=2+1$

Dalmazi, D.; Mendonça, Elias L.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
76.426914%
The direct sum of a couple of Maxwell-Chern-Simons (MCS) gauge theories of opposite helicities $\pm 1$ does not lead to a Proca theory in $D=2+1$, although both theories share the same spectrum. However, it is known that by adding an interference term between both helicities we can join the complementary pieces together and obtain the physically expected result. A generalized soldering procedure can be defined to generate the missing interference term. Here we show that the same procedure can be applied to join together $\pm 2$ helicity states in a full off-shell manner. In particular, by using second-order (in derivatives) self-dual models of helicities $\pm 2$ (spin two analogues of MCS models) the Fierz-Pauli theory is obtained after soldering. Remarkably, if we replace the second-order models by third-order self-dual models (linearized topologically massive gravity) of opposite helicities we end up after soldering exactly with the new massive gravity theory of Bergshoeff, Hohm and Townsend in its linearized approximation.; Comment: 12 pages, to appear in Phys. Rev. D

## Dual descriptions of massive spin-3 particles in $D=2+1$ via Noether gauge embedment

Mendonça, E. L.; Dalmazi, D.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
76.384307%
We present here a relationship among massive self-dual models for spin-3 particles in $D=2+1$ via the Noether Gauge Embedment $(NGE)$ procedure. Starting with a first order model (in derivatives) $S_{SD(1)}$ we have obtained a sequence of four self-dual models $S_{SD(i)}$ where $i=1,2,3,4$. We demonstrate that the $NGE$ procedure generate the correct action for the auxiliary fields automatically. We obtain the whole action for the $4th$ order self-dual model including all the needed auxiliary fields to get rid of the ghosts of the theory.; Comment: 16 pages, 1 table

## The D(2,1;\alpha) Particle

Corney, S P; Jarvis, P D; McAnally, D S
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
76.535884%
The exceptional superalgebra $D(2,1;\alpha)$ has been classified as a candidate conformal supersymmetry algebra in two dimensions. We propose an alternative interpretation of it as extended BFV-BRST quantisation superalgebras in 2D ($D(2,1;1) \simeq osp(2,2|2)$). A superfield realization is presented wherein the standard extended phase space coordinates can be identified. The physical states are studied via the cohomology of the BRST operator. It is conjectured that the underlying model giving rise to this `quantisation' is that of a scalar relativistic particle in 1+1 dimensions, for which the light cone coordinates $x_R$, $x_L$ transform under worldline diffeomorphisms as scalar densities of appropriate weight.; Comment: 6 pages, talk given at the 22nd International Colloqium for Group Theoretical Methods in Physics

## Master actions for massive spin-3 particles in D=2+1

Mendonça, E. L.; Dalmazi, D.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.396323%
We present here a relationship among massive self-dual models for spin-3 particles in $D=2+1$ via the master action procedure. Starting with a first order model (in derivatives) $S_{SD(1)}$ we have constructed a master action which interpolates among a sequence of four self-dual models $S_{SD(i)}$ where $i=1,2,3,4$. By analyzing the particle content of mixing terms, we give additional arguments that explain why it is apparently impossible to jump from the fourth order model to a higher order model. We have also analyzed similarities and differences between the fourth order $K$-term in the spin-2 case and the analogous fourth order term in the spin-3 context.; Comment: 16 pages

## A new spin-2 self-dual model in $D=2+1$

Dalmazi, D.; Mendonca, E. L.
There are three self-dual models of massive particles of helicity +2 (or -2) in $D=2+1$. Each model is of first, second, and third-order in derivatives. Here we derive a new self-dual model of fourth-order, $\cL {SD}^{(4)}$, which follows from the third-order model (linearized topologically massive gravity) via Noether embedment of the linearized Weyl symmetry. In fact, each self-dual model can be obtained from the previous one $\cL {SD}^{(i)} \to \cL {SD}^{(i+1)}, i=1,2,3$ by the Noether embedment of an appropriate gauge symmetry, culminating in $\cL {SD}^{(4)}$. The new model may be identified with the linearized version of $\cL {HDTMG} = \epsilon^{\mu\nu\rho} \Gamma_{\mu\gamma}^\epsilon (\p_\nu\Gamma_{\epsilon\rho}^\gamma + (2/3)\Gamma_{\nu\delta}^\gamma \Gamma_{\rho\epsilon}^\delta) /8 m + \sqrt{-g}(R_{\mu\nu} R^{\nu\mu} - 3 R^2/8) /2 m^2$. We also construct a master action relating the third-order self-dual model to $\cL {SD}^{(4)}$ by means of a mixing term with no particle content which assures spectrum equivalence of $\cL {SD}^{(4)}$ to other lower-order self-dual models despite its pure higher derivative nature and the absence of the Einstein-Hilbert action. The relevant degrees of freedom of $\cL {SD}^{(4)}$ are encoded in a rank-two tensor which is symmetric...