177,497 research outputs found
The shrimp mitochondrial FoF1-ATPase inhibitory factor 1 (IF1)
No full textThe whiteleg shrimp species Litopenaeus vannamei is exposed to cyclic changes of the dissolved oxygen concentration of seawater and must neutralize the adverse effects of hypoxia by using ATP as energy source. In crustaceans, the mitochondrial FOF1-ATP synthase is pivotal to the homeostasis of ATP and function prevalently as a FOF1-ATPase. Hitherto, it is unknown whether these marine invertebrates are equipped with molecules able to control the FOF1-ATPase inhibiting the ATP consumption. In this study, we report two variants of the mitochondrial FOF1-ATPase Inhibitory Factor 1 (IF1) ubiquitously expressed across tissues of the Litopenaeus vannamei transcriptome: the IF1_Lv1 and the IF1_Lv2. The IF1_Lv1, with a full-length sequence of 550 bp, encodes a 104 aa long protein and its mRNA amounts are significantly affected by hypoxia and re-oxygenation. The IF1_Lv2, with a sequence of 654 bp, encodes instead for a protein of 85 aa. Both proteins share a 69 % homology and contain a conserved minimal inhibitory sequence (IATP domain) along with a G-rich region on their N-terminus typical of the invertebrate. In light of this characterization IF1 is here discussed as an adaptive mechanism evolved by this marine species to inhibit the FOF1-ATPase activity and avoid ATP dissipation to thrive in spite of the changes in oxygen tension.Fil: Chimeo, Cindy. Centro de Investigacion en Alimentacion y Desarrollo; MéxicoFil: Fernandez Gimenez, Analia Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Campanella, Michelangelo. University of London; Reino Unido. University College London; Estados UnidosFil: Mendez Romero, Ofelia. Centro de Investigacion en Alimentacion y Desarrollo; MéxicoFil: Muhlia Almazan, Adriana. Centro de Investigacion en Alimentacion y Desarrollo; Méxic
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
I calcestruzzi ad alte prestazioni nei riguardi delle azioni di natura chimico-fisica e della durabilità
No full textMitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
A High-Statistics Lattice Calculation of and in the meson
No full textWe present a high-statistics lattice calculation of the kinetic energy of the heavy quark inside the -meson and of the chromo-magnetic term , related to the -- mass splitting, performed in the HQET. Our results have been obtained from a numerical simulation based on 600 gauge field configurations generated at , on a lattice volume and using, for the meson correlators, the results obtained with the SW-Clover improved lattice action for the light quarks. For the kinetic energy we found ~GeV, which is interesting for phenomenological applications. We also find GeV, which is about one half of the experimental value. The origin of the discrepancy with the experimental number needs to be clarified.We present a high-statistics lattice calculation of the kinetic energy of the heavy quark inside the -meson and of the chromo-magnetic term , related to the -- mass splitting, performed in the HQET. Our results have been obtained from a numerical simulation based on 600 gauge field configurations generated at , on a lattice volume and using, for the meson correlators, the results obtained with the SW-Clover improved lattice action for the light quarks. For the kinetic energy we found GeV, which is interesting for phenomenological applications. We also find GeV, corresponding to GeV, which is about one half of the experimental value. The origin of the discrepancy with the experimental number needs to be clarified.We present a high-statistics lattice calculation of the kinetic energy of the heavy quark inside the -meson and of the chromo-magnetic term , related to the -- mass splitting, performed in the HQET. Our results have been obtained from a numerical simulation based on 600 gauge field configurations generated at , on a lattice volume and using, for the meson correlators, the results obtained with the SW-Clover improved lattice action for the light quarks. For the kinetic energy we found GeV, which is interesting for phenomenological applications. We also find GeV, corresponding to GeV, which is about one half of the experimental value. The origin of the discrepancy with the experimental number needs to be clarified.We present a high-statistics lattice calculation of the kinetic energy of the heavy quark inside the -meson and of the chromo-magnetic term , related to the -- mass splitting, performed in the HQET. Our results have been obtained from a numerical simulation based on 600 gauge field configurations generated at , on a lattice volume and using, for the meson correlators, the results obtained with the SW-Clover improved lattice action for the light quarks. For the kinetic energy we found GeV, which is interesting for phenomenological applications. We also find GeV, corresponding to GeV, which is about one half of the experimental value. The origin of the discrepancy with the experimental number needs to be clarified.We present a high-statistics lattice calculation of the kinetic energy − λ 1 /2 m b of the heavy quark inside the B -meson and of the chromo-magnetic term A2, related to the B ∗ −B mass splitting, performed in the HQET Our results have been obtained from a numerical simulation based on 600 gauge field configurations generated at β = 6.0, on a lattice volume 24 3 × 40 and using, for the meson correlators, the results obtained with the SW-Clover O ( a ) improved lattice action for the light quarks. For the kinetic energy we found −λ 1 = 〈B| h ̄ (iD) 2 h|B〉/(2M B ) = −(0.09 ± 0.14) GeV 2 , which is interesting for phenomenological applications. We also found λ 2 = 0.07 ± 0.01 GeV 2 , corresponding to M B∗ 2 − M B 2 = 4λ 2 = 0.280 ± 0.060 GeV 2 , which is about one half of the experimental value. The origin of the discrepancy with the experimental number needs to be clarified
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Anticuerpos Antirreceptores a Neurotransmisores y su Correlacion con la Alteracion de la Dispersión del QT y de la Variabilidad de la Frecuencia Cardiaca
No full textFil: Mitelman, Jorge E. Instituto Universitario de Ciencias de la Salud. Fundación Barceló; Argentina.Fil: Gimenez, Luisa. Instituto Universitario de Ciencias de la Salud. Fundación Barceló; Argentina.Fil: Pugliese, O. Instituto Universitario de Ciencias de la Salud. Fundación Barceló; Argentina.Fil: Sturgeom, C. Instituto Universitario de Ciencias de la Salud. Fundación Barceló; Argentina.Estudiar la asociación entre las alteraciones de la variabilidad de la frecuencia cardiaca (VFC); dispersión del qt y la presencia de anticuerpos antirreceptores a neurotrasmisores en la enfermedad de Chagas (con o sin cardiopatía)
First lattice calculation of the B-meson binding and kinetic energies
No full textWe present the first lattice calculation of the B-meson binding energy \labar and of the kinetic energy -\lambda_1/2 m_Q of the heavy-quark inside the pseudoscalar B-meson. This calculation has required the non-perturbative subtraction of the power divergences present in matrix elements of the Lagrangian operator \bar h D_4 h and of the kinetic energy operator \bar h \vec D^2 h. The non-perturbative renormalisation of the relevant operators has been implemented by imposing suitable renormalisation conditions on quark matrix elements, in the Landau gauge. Our numerical results have been obtained from several independent numerical simulations at \beta=6.0 and 6.2, and using, for the meson correlators, the results obtained by the APE group at the same values of \beta. Our best estimate, obtained by combining results at different values of \beta, is \labar =190 \err{50}{30} MeV. For the \overline{MS} running mass, we obtain \overline {m}_b(\overline {m}_b) =4.17 \pm 0.06 GeV, in reasonable agreement with previous determinations. From a subset of 36 configurations, we were only able to establish a loose upper bound on the b-quark kinetic energy in a B-meson, \lambda_1=\langle B \vert \bar h \vec{D}^{2} h \vert B \rangle /(2 M_B )<~1\, GeV^2. This shows that a much larger statistical sample is needed to determine this important parameter.We present the first lattice calculation of the B-meson binding energy \labar and of the kinetic energy of the heavy-quark inside the pseudoscalar B-meson. This calculation has required the non-perturbative subtraction of the power divergences present in matrix elements of the Lagrangian operator and of the kinetic energy operator . The non-perturbative renormalisation of the relevant operators has been implemented by imposing suitable renormalisation conditions on quark matrix elements, in the Landau gauge. Our numerical results have been obtained from several independent numerical simulations at and , and using, for the meson correlators, the results obtained by the APE group at the same values of . Our best estimate, obtained by combining results at different values of , is \labar =190 \err{50}{30} MeV. For the running mass, we obtain GeV, in reasonable agreement with previous determinations. From a subset of 36 configurations, we were only able to establish a loose upper bound on the -quark kinetic energy in a -meson, 1\, GeV. This shows that a much larger statistical sample is needed to determine this important parameter.We present the first lattice calculation of the B-meson binding energy Λ and of the kinetic energy − λ 1 /2 m Q of the heavy-quark inside the pseudoscalar B-meson. This calculation has required the non-perturbative subtraction of the power divergences present in matrix elements of the Lagrangian operator h − D 4 h and of the kinetic energy operator h − D 2 h . The non-perturbative renormalisation of the relevant operators has been implemented by imposing suitable renormalisation conditions on quark matrix elements, in the Landau gauge. Our numerical results have been obtained from several independent numerical simulations at β = 6.0 and 6.2, and using, for the meson correlators, the results obtained by the APE group at the same values of β. Our best estimate, obtained by combining results at different values of β, is Λ − = 190 −30 +50 MeV . For the MS running mass, we obtain m b ( m b ) = 4.17 ± 0.06 GeV , in reasonable agreement with previous determinations. From a subset of 36 configurations, we were only able to establish a loose upper bound on the b-quark kinetic energy in a B -meson, Λ = 〈B∥ h − D 2 h∥B〉/(2M B ) < 1 GeV 2 . This shows that a much larger statistical sample is needed to determine this important parameter
Forecasting ocean warming impacts on seabird demography: a case study on the European storm petrel
No full textBottom-up climatic forcing has been shown to be influential for a variety of marine
taxa, but evidence on seabird populations is scarce. Seasonal variation in environmental conditions
can have an indirect effect on subsequent reproduction, which, given the longevity and
single-brooding of seabirds, may affect population dynamics. Our study focuses on linking the
effect of oceanographic conditions (from 1991 to 2013) to the fecundity and consequently pop -
ulation growth rate of the Mediterranean subspecies of the European storm petrel Hydrobates
pelagicus melitensis. In this study, we examined 23 yr of > 5400 capture–mark−recaptures (CMR)
and modelled the probability of skipping reproduction as a function of oceanographic variables
using CMR models. We demonstrate that a decrease in sea surface temperature in the pre-breeding
period negatively influences skipping propensity, and therefore hypothesize that this behaviour
would have significant influence on population abundance over time. For this reason, we analysed
population growth as a function of skipping probability as affected by oceanographic
conditions. We used stochastic demographic models to forecast the fate of the population, and
evaluated contrasted environmental condition scenarios. As a result, we found that a decrease in
frequency of cold winter events would probably reduce skipping propensity, with a positive effect
on the population as a whole
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