136 research outputs found
Atlantic water flow into the Arctic Ocean through the St. Anna Trough in the northern Kara Sea
The Atlantic Water flow from the Barents and Kara seas to the Arctic Ocean through the St. Anna Trough (SAT) is conditioned by interaction between Fram Strait branch water circulating in the SAT and Barents Sea branch water—both of Atlantic origin. Here we present data from an oceanographic mooring deployed on the eastern flank of the SAT from September 2009 to September 2010 as well as CTD (conductivity-temperature-depth) sections across the SAT. A distinct vertical density front over the SAT eastern slope deeper than ∼50 m is attributed to the outflow of Barents Sea branch water to the Arctic Ocean. In turn, the Barents Sea branch water flow to the Arctic Ocean is conditioned by two water masses defined by relative low and high fractions of the Atlantic Water. They are also traceable in the Nansen Basin downstream of the SAT entrance. A persistent northward current was recorded in the subsurface layer along the SAT eastern slope with a mean velocity of 18 cm s−1 at 134–218 m and 23 cm s−1 at 376–468 m. Observations and modeling suggest that the SAT flow has a significant density-driven component. It is therefore expected to respond to changes in the cross-trough density gradient conditioned by interaction between the Fram Strait and Barents Sea branches. Further modeling efforts are necessary to investigate hydrodynamic instability and eddy generation caused by the interaction between the SAT flow and the Arctic Ocean Fram Strait branch water boundary current
Casimir scaling as a test of QCD vacuum
Recent accurate measurements of static potentials between sources in various
representations of the gauge group SU(3) performed by G.Bali provide a crucial
test of the QCD vacuum models and different approaches to confinement. The
Casimir scaling of the potential observed for all measured distances implies
strong suppression of higher cumulant contributions. The consequences for the
instanton vacuum model and the spectrum of the QCD string are also discussed.Comment: LaTeX, 15 pages, 1 figur
Tree-level (pi, K)-amplitude and analyticity
We consider the tree-level amplitude, describing all 3 channels of the binary
(pi ,K)-reaction, as a meromorphic polynomially bounded function of 3 dependent
complex variables. Relying systematically on the Mittag-Leffler theorem, we
construct 3 convergent partial fraction expansions, each one being applied in
the corresponding domain. Noting, that the mutual intersections of those
domains are nonempty, we realize the analytical continuation. It is shown that
the necessary conditions to make such a continuation feasible, are the
following: 1) The only parameters completely determining the amplitude are the
on-shell couplings and masses; 2) These parameters are restricted by a certain
(infinite) system of bootstrap equations; 3) The full cross-symmetric amplitude
takes the typically dual form, the Pomeron contribution being taken into
account; 4)This latter contribution corresponds to a nonresonant background,
which, in turn, is expressed in terms of cross-channel resonances parameters.
It is demonstrated also, that the Chiral Symmetry provides a unique scale for
the mentioned parameters, the resonance saturation effect appearing as a direct
consequence of the above results
NADP-Dependent Aldehyde Dehydrogenase from Archaeon Pyrobaculum sp.1860
We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. In vitro, AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60–85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.04 Å resolution), three binary complexes with the coenzyme (1.90, 2.06, and 2.19 Å), and the ternary complex with the coenzyme and isobutyraldehyde as a substrate (2.66 Å). The nicotinamide moiety of the coenzyme is disordered in two binary complexes, while it is ordered in the ternary complex, as well as in the binary complex obtained after additional soaking with the substrate. AlDHPyr1147 structures demonstrate the strengthening of the dimeric contact (as compared with the analogues) and the concerted conformational flexibility of catalytic Cys287 and Glu253, as well as Leu254 and the nicotinamide moiety of the coenzyme. A comparison of the active sites of AlDHPyr1147 and dehydrogenases characterized earlier suggests that proton relay systems, which were previously proposed for dehydrogenases of this family, are blocked in AlDHPyr1147, and the proton release in the latter can occur through the substrate channel
Effective Chiral Lagrangian from Dual Resonance Models
Parameters of the effective chiral lagrangian (EChL) of orders and
are extracted from low--energy behaviour of dual resonance models for
and scattering amplitudes. Dual resonance models are
considered to be good candidates for the resonance spectrum and for hadronic
scattering amplitudes in the large limit of QCD. We discuss dual
resonance models in the presence of spontaneous and explicit chiral symmetry
breaking. Obtained parameters of the EChL are used to estimate chiral
corrections up to the sixth order to various low--energy characteristics of
and scattering amplitudes.Comment: 32 pages, the references list is updated, comparison with chiral
quark model is done in more detail
The Polarised Valence Quark Distribution from semi-inclusive DIS
The semi-inclusive difference asymmetry A^{h^{+}-h^{-}} for hadrons of
opposite charge has been measured by the COMPASS experiment at CERN. The data
were collected in the years 2002-2004 using a 160 GeV polarised muon beam
scattered off a large polarised ^6LiD target and cover the range 0.006 < x <
0.7 and 1 < Q^2 < 100 (GeV/c)^2. In leading order QCD (LO) the asymmetry
A_d^{h^{+}-h^{-}} measures the valence quark polarisation and provides an
evaluation of the first moment of Delta u_v + Delta d_v which is found to be
equal to 0.40 +- 0.07 (stat.) +- 0.05 (syst.) over the measured range of x at
Q^2 = 10 (GeV/c)^2. When combined with the first moment of g_1^d previously
measured on the same data, this result favours a non-symmetric polarisation of
light quarks Delta u-bar = - Delta d-bar at a confidence level of two standard
deviations, in contrast to the often assumed symmetric scenario Delta u-bar =
Delta d-bar = Delta s-bar = Delta s.Comment: 7 pages, 3 figures, COMPASS, revised: details added, author list
update
Retinoblastoma seeds: Impact on American Joint Committee on Cancer clinical staging
Aim To investigate whether the American Joint Committee on Cancer (AJCC) clinical category cT2b needs to be subclassified by the type and distribution of retinoblastoma (RB) seeding. Methods Multicentre, international registry-based data were collected from RB centres enrolled between January 2001 and December 2013. 1054 RB eyes with vitreous or subretinal seeds from 18 ophthalmic oncology centres, in 13 countries within six continents were analysed. Local treatment failure was defined as the use of secondary enucleation or external beam radiation therapy (EBRT) and was estimated with the Kaplan-Meier method. Results Clinical category cT2b included 1054 eyes. Median age at presentation was 16.0 months. Of these, 428 (40.6%) eyes were salvaged, and 430 (40.8%) were treated with primary and 196 (18.6%) with secondary enucleation. Of the 592 eyes that had complete data for globe salvage analysis, the distribution of seeds was focal in 143 (24.2%) and diffuse in 449 (75.8%). The 5-year Kaplan-Meier cumulative globe-salvage (without EBRT) was 78% and 49% for eyes with focal and diffuse RB seeding, respectively. Cox proportional hazards regression analysis confirmed a higher local treatment failure risk with diffuse seeds as compared with focal seeds (hazard rate: 2.8; p<0.001). There was insufficient evidence to prove or disprove an association between vitreous seed type and local treatment failure risk(p=0.06). Conclusion This international, multicentre, registry-based analysis of RB eyes affirmed that eyes with diffuse intraocular distribution of RB seeds at diagnosis had a higher risk of local treatment failure when compared with focal seeds. Subclassification of AJCC RB category cT2b into focal vs diffuse seeds will improve prognostication for eye salvage.Fil: Tomar, Ankit Singh. New York Eye Cancer Center; Estados UnidosFil: Finger, Paul T.. New York Eye Cancer Center; Estados UnidosFil: Gallie, Brenda. University Of Toronto. Hospital For Sick Children; CanadáFil: Kivelä, Tero. University of Helsinki; Finlandia. Helsinki University Hospital; FinlandiaFil: Mallipatna, Ashwin. University Of Toronto. Hospital For Sick Children; Canadá. Narayana Nethralaya; IndiaFil: Zhang, Chengyue. Beijing Children's Hospital; ChinaFil: Zhao, Junyang. Beijing Children's Hospital; ChinaFil: Wilson, Matthew. University of Tennessee; Estados UnidosFil: Brennan, Rachel. St Jude Children's Research Hospital; Estados UnidosFil: Burges, Michala. University of Tennessee; Estados UnidosFil: Kim, Jonathan. Keck Medical School of the University of Southern California; Estados UnidosFil: Berry, Jesse L.. Children's Hospital Los Angeles; Estados UnidosFil: Jubran, Rima. Childrens Hospital Society of Los Angeles; Estados UnidosFil: Khetan, Vikas. Vitreo Retinal Services; IndiaFil: Ganeshan, Suganeswari. Vitreo Retinal Services; IndiaFil: Yarovoy, Andrey. Fyodorov Eye Microsurgery Federal State Institution; RusiaFil: Yarovaya, Vera. Fyodorov Eye Microsurgery Federal State Institution; RusiaFil: Kotova, Elena. Fyodorov Eye Microsurgery Federal State Institution; RusiaFil: Volodin, Denis. Fyodorov Eye Microsurgery Federal State Institution; RusiaFil: Yousef, Yacoub. King Hussein Cancer Center; JordaniaFil: Nummi, Kalle. University of Helsinki; Finlandia. Helsinki University Hospital; FinlandiaFil: Ushakova, Tatiana L.. N.N. Blokhin Russian Cancer Research Center; Rusia. Russian Academy of Postgraduate Medical Education; RusiaFil: Yugay, Olga V.. N.N. Blokhin Russian Cancer Research Center; RusiaFil: Polyakov, Vladimir G. N.N. Blokhin Russian Cancer Research Center; Rusia. Russian Academy of Sciences; RusiaFil: Ramirez Ortiz, Marco Antonio. Hospital Infantil de Mexico Federico Gomez; MéxicoFil: Esparza Aguiar, Elizabeth. Hospital Infantil de Mexico Federico Gomez; MéxicoFil: Chantada, Guillermo Luis. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrÃa "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Schaiquevich, Paula Susana. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrÃa "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Fandiño, Adriana Cristina. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrÃa "Juan P. Garrahan"; ArgentinaFil: Yam, Jason C.. The Chinese University of Hong Kong Faculty of Medicine; Hong Kon
The role of maternal age & birth order on the development of unilateral and bilateral retinoblastoma: a multicentre study
BACKGROUND/OBJECTIVES: Retinoblastoma is a common childhood intraocular malignancy, the bilateral form of which most commonly results from a de novo germline pathogenic variant in the RB1 gene. Both advanced maternal age and decreasing birth order are known to increase the risk of de novo germline pathogenic variants, while the influence of national wealth is understudied. This cohort study aimed to retrospectively observe whether these factors influence the ratio of bilateral retinoblastoma cases compared to unilateral retinoblastoma, thereby inferring an influence on the development of de novo germline pathogenic variants in RB1. SUBJECTS/METHODS: Data from 688 patients from 11 centres in 10 countries were analysed using a series of statistical methods. RESULTS: No associations were found between advanced maternal age, birth order or GDP per capita and the ratio of bilateral to unilateral retinoblastoma cases (p values = 0.534, 0.201, 0.067, respectively), indicating that these factors do not contribute to the development of a de novo pathogenic variant. CONCLUSIONS: Despite a lack of a definitive control group and genetic testing, this study demonstrates that advanced maternal age, birth order or GDP per capita do not influence the risk of developing a bilateral retinoblastoma
Development of 3D detectors at FBK-irst
We report on the development of 3D detectors at Fondazione Bruno Kessler - irst in the framework of the CERN RD-50 Collaboration. Technological and design aspects dealing with the 3D Single Type Column detectors are reviewed, and selected results from the electrical and functional characterization of prototypes are reported and discussed. A new detector concept, namely 3D Double-side Double Type Column detectors, allowing for significant performance enhancement while maintaining a reasonable process complexity, is final ly addressed
Lag Time between Onset of First Symptom and Treatment of Retinoblastoma: An International Collaborative Study of 692 Patients from 10 Countries.
BACKGROUND: The relationship between lag time and outcomes in retinoblastoma (RB) is unclear. In this study, we aimed to study the effect of lag time between onset of symptoms and diagnosis of retinoblastoma (RB) in countries based on their national-income and analyse its effect on the outcomes. METHODS: We performed a prospective study of 692 patients from 11 RB centres in 10 countries from 1 January 2019 to 31 December 2019. RESULTS: The following factors were significantly different among different countries based on national-income level: age at diagnosis of RB (p = 0.001), distance from home to nearest primary healthcare centre (p = 0.03) and mean lag time between detection of first symptom to visit to RB treatment centre (p = 0.0007). After adjusting for country income, increased lag time between onset of symptoms and diagnosis of RB was associated with higher chances of an advanced tumour at presentation (p < 0.001), higher chances of high-risk histopathology features (p = 0.003), regional lymph node metastasis (p < 0.001), systemic metastasis (p < 0.001) and death (p < 0.001). CONCLUSIONS: There is a significant difference in the lag time between onset of signs and symptoms and referral to an RB treatment centre among countries based on national income resulting in significant differences in the presenting features and clinical outcomes
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