Praeornis sharovi Rautian, 1978 a fossil feather from the early Late Jurassic of Kazakhstan

Since its original description as a feather belonging to a basal bird, the phylogenetic position of Praeornis sharovi was debated. It was considered as belonging to a bird, a cycad leaf, or as a ‘transitional’ integumentary structure between reptile scales and bird feathers. Recently, a basal enantiornithine bird was collected in Early Cretaceous beds of Brazil. This specimen shows very well-preserved rachis-dominated tail feathers with a very thick rachis and thick and rigid barbules. These features are present in Praeornis, suggesting that this fossil may be interpreted as the tail feather of a basal bird. In this way, Praeornis constitutes one of the oldest records of rachis-dominated feathers in the world. Rachis-dominated tail feathers, including that of Praeornis appear to be rigid paired structures not performed for aerodynamical purposes, suggesting that may be important in body balance

Interference effects in the H(→ γγ) + 2 jets channel at the LHC

We compute the interference between the resonant process pp → H(→ γγ) + 2 jets and the corresponding continuum background at leading order in QCD. For the Higgs signal, we include gluon fusion (GF) and vector boson fusion (VBF) production channels, while for the background we consider all tree-level contributions, including pure EW effects (O(α 4 QED)) and QCD contributions (O(α 2 QEDα 2 s )), plus the loopinduced gluon-initiated process. After convolution with the experimental mass resolution, the main effect of the interference is to shift the position of the mass peak, as in the inclusive GF case studied previously. The apparent mass shift is small in magnitude but strongly dependent on the Higgs width, potentially allowing for a measurement of, or bound on, the width itself. In the H(→ γγ) + 2 jets channel, the VBF and GF contributions generate shifts of opposite signs which largely cancel, depending on the sets of cuts used, to as little as 5 MeV (toward a lower Higgs mass). The small magnitude of the shift makes this channel a good reference mass for measuring the inclusive mass shift of around 60 MeV in the Standard Model.Fil: Coradeschi, F.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Università degli Studi di Firenze; ItaliaFil: de Florian, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Dixon, L. J.. University of Stanford; Estados Unidos. Walter Burke Institute for Theoretical Physics; Estados UnidosFil: Fidanza Romani, Nerina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Höche, S.. University of Stanford; Estados UnidosFil: Ita, H.. Albert Ludwigs Universität Freiburg; AlemaniaFil: Li, Y.. University of Stanford; Estados UnidosFil: Mazzitelli, Javier Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin

Form factors and decoupling of matter fields in four-dimensional gravity

We extend previous calculations of the non-local form factors of semiclassical gravity in $4D$ to include the Einstein-Hilbert term. The quantized fields are massive scalar, fermion and vector fields. The non-local form factor in this case can be seen as the sum of a power series of total derivatives, but it enables us to derive the beta function of Newton's constant and formally evaluate the decoupling law in the new sector, which turns out to be the standard quadratic one.Comment: 17 pages, 2 figures; v2: improved the discussion of section

On the Entropy and the Density Matrix of Cosmological Perturbations

We look at the transition to the semiclassical behaviour and the decoherence process for the inhomogeneous perturbations in the inflationary universe. Two different decoherence mechanisms appear: one dynamical, accompanied with a negligible, if at all, entropy gain, and the other, effectively irreversible dephasing, due to a rapid variation in time of the off-diagonal density matrix elements in the post-inflationary epoch. We thus settle the discrepancies in the entropy content of perturbations evaluated by different authors.Comment: LaTeX2e with the epsf packag

Toxicological Study Employing Repeated Doses of Garcinielliptone FC, a Polyisoprenylated-Benzophenone Isolated from Seed of Platonia Insignis Mart

The major constituent from the hexane extract of the seeds of P. insignis is GFC (garcinielliptone FC). Doses of 25, 50and 75 mg/kg of GFC were aseptically suspended in 0.05% Tween 80 dissolved in 0.9% saline (vehicle) and orally administered for30, 90 and 120 consecutive days to adult Swiss mice. In this work, the repeated oral administration, in animals of both sexes,demonstrates that this compound is not able to induce mortality and/or behavioral changes in adult mice. In addition, body weightgain, feed intake and disposal of excreta were not altered by the administration of this compound with repeated doses. Furthermore,no differences in weight and macroscopic structure of the brain, liver, kidney, lung, heart and spleen between groups of male andfemale adult mice were observed after treatment. During the periods of treatment, GFC produced no significant changes onhaematological and biochemical parameters in male and female mice treated with all doses used. The aim of this study was toinvestigate the toxicological potential of GFC through behavioral, hematological, biochemical and morphological parameters inanimals in order to ensure the safe use of Platonia insignis in folk medicine.Fil: Silva, Ana P.. Federal University of Piauí; BrasilFil: Filho, José Carlos C. L. S.. North Union of Parana; BrasilFil: da Costa Júnior, Joaquim S.. Federal Institute of Piauí; BrasilFil: Peláez, Walter José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Faillace, Martín Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Falcão Ferraz, Alexandre de B.. Lutheran University of Brazil; BrasilFil: David, Jorge M.. Institute Of Chemistry, Federal University Of Bahia; Brasil. Universidade Federal da Bahia; BrasilFil: Freitas, Rivelilson M.. Federal University of Bahia; Brasi

Influencia de diferentes temperaturas de sustrato y concentraciones de ácido indolbutírico en el esquejado de Coriaria myrtifolia

Se estudia Coriaria myrtifolia Linn., especie autóctona de interés ecológico (fijadora de N), medicinal (coriamirtina en los frutos) y ornamental (uso en reforestación de zonas pobres en N y como verde de complemento en floristería y en jardinería). Se pretende mejorar su multiplicación por esqueje, mediante uso de ácido indolbutírico (AIB) como hormona favorecedora del enraizamiento que ya ha mostrado su efectividad en numerosas especies, entre ellas Nerium oleander (Kose, 2000), también autóctona del Mediterráneo.Trabajo financiado por los proyectos: MCYT-FEDER AGL2001-2249-C03-01 y AGL2000-052 CICYT-FEDER. Expresamos nuestro agradecimiento a la Dir. Gral. de Investigación y Transf. Tecnológica de la Consejería de Agricultura, Agua y Medio Ambiente de la Región de Murcia por su colaboración para la ejecución de este trabaj

Magnetite mineralization inside cross-linked protein crystals

Crystallization in confined spaces is a widespread process in nature that also has important implications for the stability and durability of many man-made materials. It has been reported that confinement can alter essential crystallization events, such as nucleation and growth and, thus, have an impact on crystal size, polymorphism, morphology, and stability. Therefore, the study of nucleation in confined spaces can help us understand similar events that occur in nature, such as biomineralization, design new methods to control crystallization, and expand our knowledge in the field of crystallography. Although the fundamental interest is clear, basic models at the laboratory scale are scarce mainly due to the difficulty in obtaining well-defined confined spaces allowing a simultaneous study of the mineralization process outside and inside the cavities. Herein, we have studied magnetite precipitation in the channels of cross-linked protein crystals (CLPCs) with different channel pore sizes, as a model of crystallization in confined spaces. Our results show that nucleation of an Fe-rich phase occurs inside the protein channels in all cases, but, by a combination of chemical and physical effects, the channel diameter of CLPCs exerted a precise control on the size and stability of those Fe-rich nanoparticles. The small diameters of protein channels restrain the growth of metastable intermediates to around 2 nm and stabilize them over time. At larger pore diameters, recrystallization of the Fe-rich precursors into more stable phases was observed. This study highlights the impact that crystallization in confined spaces can have on the physicochemical properties of the resulting crystals and shows that CLPCs can be interesting substrates to study this process

Meta-action research with pre-service teachers: a case study

This article analyses a case of action research collaboratively conducted by a university teacher and 50 students in a master's course in teacher training. Its originality resides in the socio-economic, academic, and conceptual nature of the obstacles encountered in the module; in the meta-theoretical orientation of the action research that was chosen to overcome them; and in how triangulation strategies were devised to compensate for the limitations imposed by the academic framing of the course. In spite of the brevity of the research cycle, both the structure of the course and teacher-student interaction improved rapidly and significantly, as did the latter's trust in the teacher. As a result, important advances in learning also ensued, and the pedagogical potential of this research method was thereby confirmed