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The C(K, X) spaces for compact metric spaces K and X with a uniformly convex maximal factor

GALEGO, Eloi Medina
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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In this paper, we prove that if a Banach space X contains some uniformly convex subspace in certain geometric position, then the C(K, X) spaces of all X-valued continuous functions defined on the compact metric spaces K have exactly the same isomorphism classes that the C(K) spaces. This provides a vector-valued extension of classical results of Bessaga and Pelczynski (1960) [2] and Milutin (1966) [13] on the isomorphic classification of the separable C(K) spaces. As a consequence, we show that if 1 < p < q < infinity then for every infinite countable compact metric spaces K(1), K(2), K(3) and K(4) are equivalent: (a) C(K(1), l(p)) circle plus C(K(2), l(q)) is isomorphic to C(K(3), l(p)) circle plus (K(4), l(q)). (b) C(K(1)) is isomorphic to C(K(3)) and C(K(2)) is isomorphic to C(K(4)). (C) 2011 Elsevier Inc. All rights reserved.

Bioremediation of herbicide velpar K® in vitro in aqueous solution with application of EM-4 (effective microorganisms)

Ramos, Márcio Antônio Gomes; Yoshioka, Sergio Akinobu
Fonte: Brazilian Archives of Biology and Technology Publicador: Brazilian Archives of Biology and Technology
Tipo: Artigo de Revista Científica
Português
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This work assessed the bioremediation of herbicide Velpar K®, in vitro in aqueous solution, used against weeds in sugar cane in São Paulo state. The herbicide contained Hexazinone and Diuron. It was used the microbial inoculant denominated Effective Microorganisms (EM-4), pool of microorganisms from soil that contained lactic and photosynthetic bacteria, fungi, yeasts and actinomycetes for bioremediation. Results for the depth of cultivation on agar-agar inoculated with EM-4 showed the microorganisms growth in the concentrations between 0.2% and 1.0% of the Velpar K®in the gel. The analysis of high performance liquid chromatography (HPLC) showed that the EM-4 was effective for the bioremediation of the herbicide, which reached the values of 80% for diuron and 70% for hexazinone after 21 days in solution of 2:1 of Velpar K®/EM-4 ratio. These results could be useful for planning the bioremediation of contaminated areas with Velpar K®.

Ontogenia das proteínas aquaporina-4 e Kir 4.1 e o efeito de inibidores dessas proteínas sobre a secreção de S100B em fatias hipocampais de rato

Zanotto, Caroline
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
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46.48954%
A aquaporina-4 (AQP-4) é o principal canal de água localizado no sistema nervoso central (SNC). Durante o aumento do potássio (K+) extracelular, a captação de K+ pelos astrócitos está provavelmente associada com o co-transporte de água. Neste caso, a AQP-4 poderia servir como uma rota de saída para a água, e isto seria vantajoso para a liberação de K+ se a permeabilidade à água da AQP-4 fosse aumentada pela alta concentração de K+ extracelular. Diversos estudos demonstraram a sobreposição da expressão ontogenética de AQP-4 e do canal retificador interno de K+ Kir 4.1, sugerindo uma associação molecular da AQP-4 e Kir 4.1 no tamponamento espacial do K+, o que facilitaria o movimento de água através da membrana plasmática. A S100B é uma proteína expressa e secretada no SNC principalmente por astrócitos, que possui efeitos neurotróficos quando expressa em concentrações nanomolar (nM) e efeitos neurotóxicos quando presente em concentrações micromolar (μM). Foi demonstrado um aumento compensatório na AQP-4 em resposta a superexpressão de S100B, no entanto ainda não foi demonstrado se a AQP-4 ou os canais Kir 4.1 podem modular a secreção de S100B. Além disso, há poucos relatos sobre as alterações da expressão de AQP-4 e Kir 4.1 ao longo do desenvolvimento cerebral. Nós investigamos se a secreção de S100B é alterada em fatias hipocampais de ratos com diferentes idades (15...

Subcellular localization and kinetic characterization of a gill (Na +, K+)-ATPase from the giant freshwater prawn macrobrachium rosenbergii

França, Juliana L.; Pinto, Marcelo R.; Lucena, Malson N.; Garçon, Daniela P.; Valenti, Wagner Cotroni; McNamara, John C.; Leone, Francisco A.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 529-543
Português
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The stimulation by Mg2+, Na+, K+, NH 4 +, and ATP of (Na+, K+)-ATPase activity in a gill microsomal fraction from the freshwater prawn Macrobrachium rosenbergii was examined. Immunofluorescence labeling revealed that the (Na +, K+)-ATPase α-subunit is distributed predominantly within the intralamellar septum, while Western blotting revealed a single α-subunit isoform of about 108 kDa M r. Under saturating Mg2+, Na+, and K+ concentrations, the enzyme hydrolyzed ATP, obeying cooperative kinetics with V M = 115.0 ± 2.3 U mg-1, K 0.5 = 0.10 ± 0.01 mmol L-1. Stimulation by Na+ (V M = 110.0 ± 3.3 U mg-1, K 0.5 = 1.30 ± 0.03 mmol L -1), Mg2+ (V M = 115.0 ± 4.6 U mg -1, K 0.5 = 0.96 ± 0.03 mmol L-1), NH4 + (V M = 141.0 ± 5.6 U mg -1, K 0.5 = 1.90 ± 0.04 mmol L-1), and K+ (V M = 120.0 ± 2.4 U mg-1, K M = 2.74 ± 0.08 mmol L-1) followed single saturation curves and, except for K+, exhibited site-site interaction kinetics. Ouabain inhibited ATPase activity by around 73 % with K I = 12.4 ± 1.3 mol L-1. Complementary inhibition studies suggest the presence of F0F1-, Na+-, or K +-ATPases, but not V(H+)- or Ca2+-ATPases, in the gill microsomal preparation. K+ and NH4 + synergistically stimulated enzyme activity (≈25 %), suggesting that these ions bind to different sites on the molecule. We propose a mechanism for the stimulation by both NH4 +...

Nitric oxide (NO)-induced activation of large conductance Ca2+-dependent K+ channels (BKCa) in smooth muscle cells isolated from the rat mesenteric artery

Mistry, D K; Garland, C J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1998 Português
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To assess the action of nitric oxide (NO) and NO-donors on K+ current evoked either by voltage ramps or steps, patch clamp recordings were made from smooth muscle cells freshly isolated from secondary and tertiary branches of the rat mesenteric artery.Inside-out patches contained channels, the open probability of which increased with [Ca2+]i. The channels had a linear slope conductance of 212±5 pS (n=12) in symmetrical (140 mM) K+ solutions which reversed in direction at 4.4 mV. In addition, the channels showed K+ selectivity, in that the reversal potential shifted in a manner similar to that predicted by the Nernst potential for K+. Barium (1 mM) applied to the intracellular face of the channel produced a voltage-dependent block and external tetraethylammonium (TEA; at 1 mM) caused a large reduction in the unitary current amplitude. Taken together, these observations indicate that the channel most closely resembled BKCa.In five out of six inside-out patches, NO (45 or 67 μM) produced an increase in BKCa activity. In inside-out patches, BKCa activity was also enhanced in some patches with 100 or 200 μM 3-morpholino-sydnonimine (SIN-1) (4/11) and 100 μM sodium nitroprusside (SNP) (3/8). The variability in channel opening with the NO donors may reflect variability in the release of NO from these compounds.In inside-out patches...

Aminoacid Ν-substituted 1,4,7-triazacyclononane and 1,4,7,10-tetraazacyclododecane Zn²⁺, Cd²⁺ and Cu²⁺ complexes. A preparative, potentiometric titration and NMR spectroscopic study; Aminoacid Nu-substituted 1,4,7-triazacyclononane and 1,4,7,10-tetraazacyclododecane Zn(2+), Cd(2+) and Cu(2+) complexes. A preparative, potentiometric titration and NMR spectroscopic study

Plush, S.; Lincoln, S.; Wainwright, K.
Fonte: Royal Soc Chemistry Publicador: Royal Soc Chemistry
Tipo: Artigo de Revista Científica
Publicado em //2004 Português
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The pK(a)s and Zn2+, Cd2+ and Cu2+ complexation constants (K) for 1,4,7-tris[(2'S)-acetamido-2'-(methyl-3'-phenylpropionate)]-1,4,7-triazacyclononane, 1, 1,4,7-tris[(2'S)-acetamido-2'-(1'-carboxy-3'-phenylpropane)]-1,4,7-triazacyclononane, H(3)2, 1,4,7-tris[(2'S)-acetamido-2'-(methyl-3'-(1H-3-indolyl)propionate)]-1,4,7-triazacyclononane, 3, and 1,4,7,10-tetrakis[(2'S)-acetamido-2'-(methyl-3'-phenylpropionate)]-1,4,7,10-tetraazacyclododecane, 4, 1,4,7,10-tetrakis[(2'S)-acetamido-2'-(1'-carboxy-3'-phenylpropane)]-1,4,7,10-tetraazacyclododecane, H(4)5, in 20 : 80 v/v water-methanol solution are reported. The pK(a)s within the potentiometric detection range for H(3)1(3+) = 8.69 and 3.59, for H(6)2(3+) = 9.06, 6.13, 4.93 and 4.52, H(3)3(3+) = 8.79 and 3.67, H(4)4(4+) = 8.50, 5.62 and 3.77 and for H(8)5(4+) = 9.89, 7.06, 5.53, 5.46, 4.44 and 4.26 where each tertiary amine nitrogen is protonated. The complexes of 1: [Zn(1)]2+(9.00), [Cd(1)]2+ (6.49), [Cd(H1)]3+ (4.54) and [Cu(1)]2+ (10.01) are characterized by the log(K/dm3 mol(-1)) values shown in parentheses. Analogous complexes are formed by 3 and 4: [Zn(3)]2+ (10.19), [Cd(3)]2+ (8.54), [Cu(3)]2+ (10.77), [Zn(4)]2+ (11.41) [Cd(4)]2+ (9.16), [Cd(H4)]3+ (6.16) and [Cu(4)]2+ (11.71). The tricarboxylic acid H(3)2 generates a greater variety of complexes as exemplified by: [Zn(2)-] (10.68) [Zn(H2)] (6.60) [Zn(H(2)2)+] (5.15)...

Synthesis and coordination chemistry of 1,4,7,10,13-pentakis( 2-hydroxyethyl)-1,4,7,10,13-pentaazacyclopentadecane: a five armed pendant donor macrocycle

Walters, K.; Buntine, M.; Lincoln, S.; Wainwright, K.
Fonte: Royal Soc Chemistry Publicador: Royal Soc Chemistry
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
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Synthesis of the five armed pendant donor macrocycle 1,4,7,10,13-pentakis(2-hydroxyethyl)-1,4,7,10,13- pentaazacyclopentadecane (phec15) has been achieved by reaction of 1,4,7,10,13-pentaazacyclopentadecane ([15]aneN₅) with ethylene oxide in the absence of light and oxygen over an eight day period. The first three pKa values for phec15 have been determined by potentiometric titration (I = 0.1 mol dm⁻³ NEt₄ClO₄) to be 8.51 ± 0.01, 7.57 ± 0.01 and 3.74 ± 0.01, respectively, and the final two are < 2.3. The stability constants (log(K/dm³ mol⁻¹) for [M(phec15]²⁺ complexes in aqueous solution where M = Co(II), Cu(II), Zn(II), Cd(II) and Pb(II) are 7.45 ± 0.03, 14.69 ± 0.02, 8.47 ± 0.01, 12.57 ± 0.03, and 10.35 ± 0.03, respectively. Gas phase ab initio modelling predicts that phec15 adopts the trans-I configuration, by virtue of linked hydrogen bonding between the five pendant hydroxyl groups, and that [Ba(phec15)]²⁺ and [Sr(phec15)]²⁺ are ten coordinate with an approximately pentagonal prismatic structure in which the plane of the five oxygen atoms is rotated either clockwise or anticlockwise with respect to the nitrogen atom plane, giving rise to Λ and Δ enantiomers, respectively. Variable temperature ¹³C{¹H} NMR spectra support these structural predictions and in the case of [Ba(phec15)]²⁺ complete lineshape analysis gave the kinetic parameters k = (4.0 ± 0.3) × 10⁴s⁻¹...

Effects of Streptococcus thermophilus TH-4 on intestinal mucositis induced by the chemotherapeutic agent 5-Fluorouracil (5-FU)

Whitford, E.; Cummins, A.; Butler, R.; Prisciandaro, L.; Fauser, J.; Yazbek, R.; Lawrence, A.; Cheah, K.; Wright, T.; Lymn, K.; Howarth, G.
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
Publicado em //2009 Português
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Beneficial bacteria (probiotics) and probiotic-derived factors have the potential to ameliorate disorders of the intestine. The aim of this study was to compare live Streptococcus thermophilus TH-4 (TH-4), dead TH-4 and TH-4 supernatant in rats treated with 5-Fluorouracil. Rats were randomly allocated to five treatment groups (n=8-10): Saline+Water; 5-FU+Skim Milk; 5-FU+Live TH-4; 5-FU+Supernatant TH-4; and 5-FU+Dead TH-4. 5-FU (150mg.kg(-1)) was administered by a single intraperitoneal injection on day 0; animals were killed on day 4. Treatments were administered daily from days -2 to 3 via oro-gastric gavage. Metabolic parameters were measured daily. Blood was obtained by cardiac puncture, and intestinal tissues removed for quantitative and qualitative histological assessment, including: villous height and area; crypt depth and area, mitotic count and crypt fission; biochemical determination of sucrase and myeloperoxidase (MPO) activity; and disease severity scoring. One-way ANOVA statistical analyses were conducted for the majority of outcome measures. Live TH-4 significantly reduced disease severity score by 13% (p< 0.05), and partially normalised mitotic counts compared with 5-FU+Skim milk controls. Live and supernatant TH-4 reduced crypt fission by 69% and 48% (p< 0.05)...

Improved approximation algorithms for computing k disjoint paths subject to two constraints

Guo, L.; Shen, H.; Liao, K.
Fonte: Springer; Germany Publicador: Springer; Germany
Tipo: Conference paper
Publicado em //2013 Português
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For a given graph G with positive integral cost and delay on edges, distinct vertices s and t, cost bound C ∈ Z  +  and delay bound D ∈ Z  + , the k bi-constraint path (kBCP) problem is to compute k disjoint st-paths subject to C and D. This problem is known NP-hard, even when k = 1 [4]. This paper first gives a simple approximation algorithm with factor-(2,2), i.e. the algorithm computes a solution with delay and cost bounded by 2*D and 2*C respectively. Later, a novel improved approximation algorithm with ratio (1+β,max{2,1+ln1β}) is developed by constructing interesting auxiliary graphs and employing the cycle cancellation method. As a consequence, we can obtain a factor-(1.369, 2) approximation algorithm by setting 1+ln1β=2 and a factor-(1.567, 1.567) algorithm by setting 1+β=1+ln1β . Besides, by setting β = 0, an approximation algorithm with ratio (1, O(ln n)), i.e. an algorithm with only a single factor ratio O(ln n) on cost, can be immediately obtained. To the best of our knowledge, this is the first non-trivial approximation algorithm for the kBCP problem that strictly obeys the delay constraint.; Longkun Guo, Hong Shen, and Kewen Liao

Effect of placental restriction and neonatal exendin-4 treatment on postnatal growth, adult body composition and in vivo glucose metabolism in the sheep

Liu, H.; Schultz, C.G.; De Blasio, M.J.; Peura, A.M.; Heinemann, G.K.; Harryanto, H.; Hunter, D.S.; Wooldridge, A.L.; Kind, K.L.; Giles, L.C.; Simmons, R.A.; Owens, J.A.; Gatford, K.L.
Fonte: American Physiological Society Publicador: American Physiological Society
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
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Intrauterine growth restriction (IUGR) increases risks of adult type 2 diabetes (T2D) and obesity. Neonatal exendin-4 treatment can prevent diabetes in the IUGR rat, but whether this will be effective in a species where the pancreas is more mature at birth, is unknown. We therefore evaluated the effects of neonatal exendin-4 administration after experimental restriction of placental and fetal growth on growth and adult metabolic outcomes in sheep. Body composition, glucose tolerance and insulin secretion and sensitivity were assessed in singleton-born adult sheep from control (CON; n = 6 F, 4 M) and placentally restricted pregnancies (PR; n = 13 F, 7 M), and in sheep from PR pregnancies that were treated with exendin-4 as neonates (daily s.c. injections of 1 nmol.kg(-1) exendin-4; PR+EX-4; n = 11 F, 7 M). Placental restriction reduced birth weight (by 29%) and impaired glucose tolerance in the adult, but did not affect adult adiposity, insulin secretion, or insulin sensitivity. Neonatal exendin-4 suppressed growth during treatment followed by delayed catch-up growth and unchanged adult adiposity. Neonatal exendin-4 partially restored glucose tolerance in PR progeny but did not affect insulin secretion or sensitivity. Although the effects on glucose tolerance are promising...

Restricted usefulness of tetraethylammonium and 4-aminopyridine for the characterization of receptor-operated K+-channels.

Drukarch, B.; Kits, K. S.; Leysen, J. E.; Schepens, E.; Stoof, J. C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1989 Português
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1. Recently, we suggested that the D2-dopamine receptor involved in the inhibition of evoked [3H]-acetylcholine release from rat striatum is coupled to K+-channels. 2. In the present study, an attempt was made to elucidate further the role of these K+-channels, using the K+-channel blocking agents tetraethylammonium and 4-aminopyridine. With a superfusion method, the effects of both drugs on the D2-dopamine receptor-mediated inhibition of the electrically evoked release of [3H]-acetylcholine from rat striatal tissue slices was investigated. 3. Both tetraethylammonium (30 mM) and 4-aminopyridine (0.1 mM) significantly stimulated the electrically evoked release of [3H]-acetylcholine and completely abolished the effect of the selective D2-receptor agonist LY 171555 (1 microM) on evoked acetylcholine release. In addition, tetraethylammonium (0.03-30 mM) and 4-aminopyridine (0.003-1 mM) strongly increased the basal (non-evoked) release of radioactivity in a concentration-dependent manner. The results suggest that the effect of the drugs on the basal release of radioactivity and on the electrically evoked release of acetylcholine cannot exclusively be explained by their action on K+-channels. 4. Furthermore, with the use of a receptor binding assay...

Three- and four-nucleon absorption processes observed in the $K^-$-$^4$He reaction at rest

Suzuki, T.; Bhang, H.; Chiba, J.; Choi, S.; Fukuda, Y.; Hanaki, T.; Hayano, R. S.; Iio, M.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kienle, P.; Kim, J. H.; Matsuda, Y.; Ohnishi, H.; Okada, S.; Outa, H.; Sato, M.; S
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/09/2010 Português
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Correlations of back-to-back coincident $\Lambda d$ and $\Lambda t$ pairs from the stopped $K^-$ reaction on $^4$He had been investigated, thereby $\Lambda d$ and $\Lambda t$ branches of non-mesonic three- and four-nucleon absorption processes of antikaon at rest were identified as well-separable processes, respectively. The branching ratio of the three-nucleon process, ($^4$He-$K^-$)$_{atomic} \rightarrow \Lambda d "n"$, is estimated to be $(0.9 \pm 0.1 (stat) \pm 0.2 (syst)) \times 10^{-3}$ from the normalized $\Lambda d$ spectrum in a $\Lambda d n$ final state, while the fraction of the four-nucleon process, ($^4$He-$K^-$)$_{atomic} \rightarrow \Lambda t$, is obtained to be $(3.1 \pm 0.4 (stat) \pm 0.5 (syst)) \times 10^{-4}$ per stopped $K^-$.; Comment: 6 pages, 4 figures, to be submitted to Physics Letters B

Secure Top-k Query Processing on Encrypted Databases

Meng, Xianrui; Zhu, Haohan; Kollios, George
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.23812%
Privacy concerns in outsourced cloud databases have become more and more important recently and many efficient and scalable query processing methods over encrypted data have been proposed. However, there is very limited work on how to securely process top-k ranking queries over encrypted databases in the cloud. In this paper, we focus exactly on this problem: secure and efficient processing of top-k queries over outsourced databases. In particular, we propose the first efficient and provable secure top-k query processing construction that achieves adaptively IND-CQA security. We develop an encrypted data structure called \emph{EHL} and describe several secure sub-protocols under our security model to answer top-k queries. Furthermore, we optimize our query algorithms for both space and time efficiency. Finally, in the experiments, we empirically analyze our protocol using real world datasets and demonstrate that our construction is efficient and practical.

Electric field gradient wave (EFGW) in iron-based superconductor Ba(0.6)K(0.4)Fe2As2 studied by M\"ossbauer spectroscopy

Jasek, A. K.; Komedera, K.; Blachowski, A.; Ruebenbauer, K.; Bukowski, Z.; Storey, J. G.; Karpinski, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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46.33695%
The optimally doped 122 iron-based superconductor Ba(0.6)K(0.4)Fe2As2 has been studied by 57Fe Moessbauer spectroscopy versus temperature ranging from 4.2 K till 300 K with particular attention paid to the superconducting transition around 38 K. The spectra do not contain magnetic components and they exhibit quasi-continuous distribution of quadrupole split doublets. A distribution follows the electric field gradient (EFG) spatial modulation (wave) - EFGW. The EFGW is accompanied by some charge density wave (CDW) having about an order of magnitude lesser influence on the spectrum. The EFGW could be modeled as widely separated narrow sheets with the EFG increasing from small till maximum value almost linearly and subsequently dropping back to the original value in a similar fashion - across the sheet. One encounters very small and almost constant EFG between sheets. The EFGW shape and amplitude as well as the amplitude of CDW are strongly affected by a superconducting transition. All modulations are damped significantly at transition (38 K) and recover at a temperature being about 14 K lower. The maximum quadrupole splitting at 4.2 K amounts to about 2.1 mm/s, while the dispersion of CDW seen on the iron nuclei could be estimated far away from the superconducting gap opening and at low temperature as 0.5 el./a.u.^3. It drops to about 0.3 el./a.u.^3 just below transition to the superconducting state.

Spin-Peierls transition in TiPO$_4$

Law, J. M.; Hoch, C.; Glaum, R.; Heinmaa, I.; Stern, R.; Kang, J.; Lee, C.; Whangbo, M. -H.; Kremer, R. K.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/04/2011 Português
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46.30957%
We investigated the magnetic and structural properties of the quasi-one dimensional 3$d^1$-quantum chain system TiPO$_4$ ($J \sim$ 965 K) by magnetic susceptibility, heat capacity, ESR, x-ray diffraction, NMR measurements, and by density functional calculations. TiPO$_4$ undergoes two magnetostructural phase transitions, one at 111 K and the other at 74 K. Below 74 K, NMR detects two different $^{31}$P signals and the magnetic susceptibility vanishes, while DFT calculations evidence a bond alternation of the Ti...Ti distances within each chain. Thus, the 74 K phase transition is a spin-Peierls transition which evolves from an incommensurate phase existing between 111 K and 74 K.; Comment: 4 pages, 3 figures, accepted by Phys. Rev. B as a Rapid Communication

Study on the family of K3 surfaces induced from the lattice $(D_4)^3 \oplus < -2 > \oplus < 2 >

Koike, K; Shiga, H; Takayama, N; Tsutsui, T
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/03/2000 Português
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Let us consider the rank 14 lattice $P=D_4^3\oplus < -2> \oplus < 2>$. We define a K3 surface S of type P with the property that $P\subset {\rm Pic}(S) $, where ${\rm Pic}(S) $ indicates the Picard lattice of S. In this article we study the family of K3 surfaces of type P with a certain fixed multipolarization. We note the orthogonal complement of P in the K3 lattice takes the form $$ U(2)\oplus U(2)\oplus (-2I_4). $$ We show the following results: \item{(1)} A K3 surface of type P has a representation as a double cover over ${\bf P}^1\times {\bf P}^1$ as the following affine form in (s,t,w) space: $$ S=S(x): w^2=\prod_{k=1}^4 (x_{1}^{(k)}st+x_{2}^{(k)}s+x_{3}^{(k)}t+x_{4}^{(k)}), \ x_k=\pmatrix{x_{1}^{(k)}&x_{2}^{(k)}\cr x_{3}^{(k)}&x_{4}^{(k)}} \in M(2,{\bf C}). $$ We make explicit description of the Picard lattice and the transcendental lattice of S(x). \item{(2)} We describe the period domain for our family of marked K3 surfaces and determine the modular group. \par \noindent \item{(3)} We describe the differential equation for the period integral of S(x) as a function of $x\in (GL(2,{\bf C}))^4$. That bocomes to be a certain kind of hypergeometric one. We determine the rank, the singular locus and the monodromy group for it. \par \noindent \item{(4)} It appears a family of 8 dimensional abelian varieties as the family of Kuga-Satake varieties for our K3 surfaces. The abelian variety is characterized by the property that the endomorphism algebra contains the Hamilton quarternion field over ${\bf Q}$.; Comment: 26 pages...

Improved measurements of branching fractions and CP partial rate asymmetries for $B\to\omega K$ and $B\to\omega\pi$

Jen, by C. -M.; Chang, P.; Abe, K.; Abe, K.; Adachi, I.; Aihara, H.; Collaboration, for the Belle
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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We report improved measurements of $B$ to pseudoscalar-vector decays containing an $\omega$ meson in the final states. Our results are obtained from a data sample that contains $388\times 10^{6}$ $B\bar{B}$ pairs accumulated at the $\Upsilon(4S)$ resonance, with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We measure the following branching fractions: ${\mathcal B}(B^{+} \to \omega K^{+}) = [8.1\pm0.6({\rm stat.})\pm{0.6}({\rm syst.})]\times 10^{-6}$, ${\mathcal B}(B^{+} \to \omega \pi^{+}) = [6.9\pm{0.6}({\rm stat.})\pm{0.5}({\rm syst.})]\times 10^{-6}$, and ${\mathcal B}(B^{0} \to \omega K^{0}) = [4.4^{+0.8}_{-0.7}({\rm stat.})\pm{0.4}({\rm syst.})]\times 10^{-6}.$ The partial width ratio $\frac{\Gamma (B^{+}\to \omega K^{+})}{\Gamma (B^{0}\to \omega K^{0})}$ = $1.8\pm0.4({\rm stat.})\pm0.1({\rm sys.})$. We also set the 90% confidence level upper limit ${\mathcal B}(B^{0} \to \omega \pi^{0}) < 2.0\times 10^{-6}.$ In addition, we obtain the partial rate asymmetries ${\mathcal A}_{CP} = 0.05^{+0.08}_{-0.07}(\rm {stat.}) \pm 0.01(\rm {syst.})$ for $B^{+} \to \omega K^{+}$, and ${\mathcal A}_{CP} = -0.02 \pm 0.09(\rm {stat.}) \pm 0.01(\rm {syst.})$ for $B^{+}\to \omega \pi^{+}$.; Comment: 6 pages, 2 figures, 2 tables...

Measurement of $e^+ e^- \to \omega \pi^0$, $K^{\ast}(892)\bar{K}$ and $K_2^{\ast}(1430)\bar{K}$ at $\sqrt{s}$ near 10.6 GeV

Belle Collaboration; Shen, C. P.; Yuan, C. Z.; Sibidanov, A.; Wang, P.; Hayasaka, K.; Wang, X. L.; Adachi, I.; Aihara, H.; Asner, D. M.; Aushev, T.; Bakich, A. M.; Bala, A.; Bhardwaj, V.; Bhuyan, B.; Bondar, A.; Bonvicini, G.; Bozek, A.; Bračko, M.; Brow
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.381807%
Using data samples of 89 fb$^{-1}$, 703 fb$^{-1}$, and 121 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider at center-of-mass energies 10.52 GeV, 10.58 GeV, and 10.876 GeV, respectively, we study the exclusive reactions $e^+e^- \to \omega\pi^0$, $K^{\ast}(892)\bar{K}$, and $K_2^{\ast}(1430)\bar{K}$ (Charge-conjugate modes are included implicitly). Significant signals of $\omega\pi^0$, $K^{\ast}(892)^0\bar{K}^0$, and $K_2^{\ast}(1430)^-K^+$ are observed for the first time at these energies, and the energy dependencies of the cross sections are presented. On the other hand, no significant excesses for $K^{\ast}(892)^-K^+$ and $K_2^{\ast}(1430)^0 \bar{K}^0$ are found, and we set limits on the cross section ratios $R_{\rm VP} = \frac{\sigma_B(e^+e^-\to K^{\ast}(892)^0\bar K^0)} {\sigma_B(e^+e^-\to K^{\ast}(892)^-K^+)}>$ 4.3, 20.0, and 5.4, and $R_{\rm TP} = \frac{\sigma_B(e^+e^-\to K_2^{\ast}(1430)^0\bar K^0)} {\sigma_B(e^+e^-\to K_2^{\ast}(1430)^-K^+)}<$ 1.1, 0.4, and 0.6, for center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.876 GeV, respectively, at the 90% C.L.; Comment: 17 pages, 4 figures; accepted for publication as a Regular Article in Physical Review D

Galanin inhibits GLP-1 and GIP secretion via the GAL? receptor in enteroendocrine L and K cells; Galanin inhibits GLP-1 and GIP via GAL? receptor

Psichas, Arianna; Glass, Leslie L.; Sharp, Stephen J.; Reimann, Frank; Gribble, Fiona M.
Fonte: Wiley Publicador: Wiley
Tipo: Article; accepted version
Português
Relevância na Pesquisa
46.30957%
This is the author accepted manuscript. It is currently embargoed pending publication.; BACKGROUND AND PURPOSE: Galanin is a widely-expressed neuropeptide, which in the gut is thought to modulate gastrointestinal motility and secretion. We aimed to elucidate the poorly characterised mechanisms underlying the inhibitory effect of galanin and the potential involvement of G protein-coupled inwardly-rectifying potassium (GIRK, K??3) channels in glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) secretion. EXPERIMENTAL APPROACH: Purified murine L and K cells were analysed for expression of galanin receptors and GIRK subunits. Hormone secretion was measured from primary murine intestinal cultures. Intracellular cAMP was monitored in primary L cells derived from mice expressing the Epac2camps sensor under the control of the proglucagon promoter. KEY RESULTS: Galanin receptor 1 (Galr1) and GIRK channel 1 (K??3.1, Kcnj3) and 4 (K??3.4, Kcnj5) mRNA expression was highly enriched in K and L cells. Galanin and a selective GAL? receptor agonist (M617) potently inhibited GLP-1 and GIP secretion from primary small intestinal cultures. In L cells, galanin significantly inhibited the forskolin-induced cAMP response. The GIRK1/4 activator ML297 significantly reduced glucose- and IBMX-stimulated GLP-1 secretion but had no effect on GIP. The GIRK blocker tertiapin-Q (TPN-Q) did not impair galanin-mediated GLP-1 inhibition. CONCLUSIONS AND IMPLICATIONS: Galanin...

Study of CP violation in Dalitz-plot analyses of B^0 → K^+K^-K^0_S, B^+ → K^+K^-K^+, and B^+ → K^0_S K^0_S K^+

Lees, J. P.; Chao, D. S.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.
Fonte: American Physical Society Publicador: American Physical Society
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 22/06/2012 Português
Relevância na Pesquisa
46.38324%
We perform amplitude analyses of the decays B^0→K^+K^-K_S^0, B^+→K^+K^-K^+, and B^+→K_S^0K_S^0K^+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470×10^6 BB decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory. For B^+→K^+K^-K^+, we find a direct CP asymmetry in B^+→ϕ(1020)K^+ of A_(CP)=(12.8±4.4±1.3)%, which differs from zero by 2.8σ. For B^0→K^+K^-K_S^0, we measure the CP-violating phase β_(eff)(ϕ(1020)K_S^0)=(21±6±2)°. For B^+→K_S^0K_S^0K^+, we measure an overall direct CP asymmetry of A_(CP)=(4_(-5)^(+4)±2)%. We also perform an angular-moment analysis of the three channels and determine that the f_X(1500) state can be described well by the sum of the resonances f_0(1500), f_2^′(1525), and f_0(1710).