1,115 research outputs found
Saprophytic fungi on tomato phylloplane: Effect of fungicides and leaf position on abundance, composition and diversity
Fungal isolations were made from leaves of tomato plants cultivated in greenhouses in an area close to La Plata, Argentina. Three different schemes of fungicide application were evaluated: high frequency preventive sprayings (Commercial Greenhouse I), low frequency preventive applications (Commercial Greenhouse II) and no fungicide spraying (Control Greenhouse). Leaves were sampled immediately after second fruit formation from three levels of the foliage: low, medium and high. Plating dilution was used to isolate fungal species. Total c.f.u. number and species composition and diversity were assessed by the plating dilution technique. Fungal populations were most abundant on leaves from lower parts of the foliage in the Control Greenhouse. Diversity varied according to fungicide application frequency and leaf position in the canopy. Higher values were recorded for lower leaves in the Control Greenhouse compared with upper leaves from Commercial Greenhouse II. Likewise position in the canopy influenced the frequency of some species. The implications for natural biological control are discussed.Centro de Investigaciones de Fitopatologí
Pembuatan Aplikasi Perencanaan Jaringan Komputer Berbasis Android
Technology is now growing rapidly in the world, namely smartphones, making us easy to do many things in daily life - today. The number of smartphones with Android Operating System helped us in many ways, including in the field of work. Along with the development of smartphone technology that requires a data connection, the computer network becomes a matter that needs to be developed. For the sake of ease of development of the network, the need for computer network design simulation software.This application helps in the manufacture of computer network that have personal computer components, switches and routers. IP on each component mounting aided by the function checks the correct format, subnet calculator that can help calculate IP quickly, and alsothe function of static routing on the router. This application is built using the Java programming language with the android his studio as an IDE.Results of the testing system, component in ease of application make some form of assistance filling of each object. The main canvas which has rescaling makes it easy to adapt the application with device that based on Android. The function of the switch which automatically takes the IP from each end of the interface. The search function is an automatic way data transmission and will identify existing static routing makes us also can map the data transmission device
Distinct ubiquitin binding modes exhibited by SH3 domains: Molecular determinants and functional implications
SH3 domains constitute a new type of ubiquitin-binding domains. We previously showed that the third SH3 domain (SH3-C) of CD2AP binds ubiquitin in an alternative orientation. We have determined the structure of the complex between first CD2AP SH3 domain and ubiquitin and performed a structural and mutational analysis to decipher the determinants of the SH3-C binding mode to ubiquitin. We found that the Phe-to-Tyr mutation in CD2AP and in the homologous CIN85 SH3-C domain does not abrogate ubiquitin binding, in contrast to previous hypothesis and our findings for the first two CD2AP SH3 domains. The similar alternative binding mode of the SH3-C domains of these related adaptor proteins is characterised by a higher affinity to C-terminal extended ubiquitin molecules. We conclude that CD2AP/CIN85 SH3-C domain interaction with ubiquitin constitutes a new ubiquitin-binding mode involved in a different cellular function and thus changes the previously established mechanism of EGF-dependent CD2AP/CIN85 mono-ubiquitination. © 2013 Ortega Roldan et al
Comparison of two experiments on radiative neutron decay
Over 10 years ago we proposed an experiment on measuring the characteristics
of radiative neutron decay in papers [1, 2]. At the same time we had published
the theoretical spectrum of radiative gamma quanta, calculated within the
framework of the electroweak interactions, on the basis of which we proposed
the methodology for the future experiment [3,4]. However, because we were
denied beam time on the intensive cold neutron beam at ILL (Grenoble, France)
for a number of years, we could only conduct the experiment in 2005 on the
newly opened FRMII reactor of Technical University of Muenchen. The main result
of this experiment was the discovery of radiative neutron decay and the
measurement of its relative intensity B.R.= (3.2+-1.6)10-3 with C.L.=99.7% for
radiative gamma quanta with energy over 35 kev [5,6]. Over a year after our
first announcement about the results of the conducted experiment, "Nature" [7]
published a letter asserting that its authors have also measured the branching
ratio of radiative neutron decay B.R.= (3.13+-0.34)10-3 with C.L.=68% and gamma
quanta energy from 15 to 340 kev. This article aims to compare these two
experiments. It is shown that the use of strong magnetic fields in the NIST
(Washington, USA) experiment methodology not only prevents any exact
measurement of the branching ratio and identification of radiative neutron
decay events, but also makes registration of ordinary neutron decay events
impossible.Comment: contribution on conference ISINN-1
alpha^2 corrections to parapositronium decay: a detailed description
We present details of our recent calculation of alpha^2 corrections to the
parapositronium decay into two photons. These corrections are rather small and
our final result for the parapositronium lifetime agrees well with the most
recent measurement. Implications for orthopositronium decays are briefly
discussed.Comment: 18 pages, late
Order alpha^3 ln(1/alpha) Corrections to Positronium Decays
The logarithmically enhanced alpha^3 ln(1/alpha) corrections to the para- and
orthopositronium decay widths are calculated in the framework of dimensionally
regularized nonrelativistic quantum electrodynamics.In the case of
parapositronium, the correction is negative, approximately doubles the effect
of the leading logarithmic alpha^3 ln^2(1/alpha) one, and is comparable to the
nonlogarithmic O(alpha^2) one. As for orthopositronium, the correction is
positive and almost cancels the alpha^3 ln^2(1/alpha) one. The uncertainties in
the theoretical predictions for the decay widths are reduced.Comment: 10 pages (Latex); missing term added, corrected coefficient B_p used,
numerical results insignificantly change
Evanescence in Coined Quantum Walks
In this paper we complete the analysis begun by two of the authors in a
previous work on the discrete quantum walk on the line [J. Phys. A 36:8775-8795
(2003) quant-ph/0303105 ]. We obtain uniformly convergent asymptotics for the
"exponential decay'' regions at the leading edges of the main peaks in the
Schr{\"o}dinger (or wave-mechanics) picture. This calculation required us to
generalise the method of stationary phase and we describe this extension in
some detail, including self-contained proofs of all the technical lemmas
required. We also rigorously establish the exact Feynman equivalence between
the path-integral and wave-mechanics representations for this system using some
techniques from the theory of special functions. Taken together with the
previous work, we can now prove every theorem by both routes.Comment: 32 pages AMS LaTeX, 5 figures in .eps format. Rewritten in response
to referee comments, including some additional references. v3: typos fixed in
equations (131), (133) and (134). v5: published versio
Saprophytic fungi on tomato phylloplane: Effect of fungicides and leaf position on abundance, composition and diversity
Fungal isolations were made from leaves of tomato plants cultivated in greenhouses in an area close to La Plata, Argentina. Three different schemes of fungicide application were evaluated: high frequency preventive sprayings (Commercial Greenhouse I), low frequency preventive applications (Commercial Greenhouse II) and no fungicide spraying (Control Greenhouse). Leaves were sampled immediately after second fruit formation from three levels of the foliage: low, medium and high. Plating dilution was used to isolate fungal species. Total c.f.u. number and species composition and diversity were assessed by the plating dilution technique. Fungal populations were most abundant on leaves from lower parts of the foliage in the Control Greenhouse. Diversity varied according to fungicide application frequency and leaf position in the canopy. Higher values were recorded for lower leaves in the Control Greenhouse compared with upper leaves from Commercial Greenhouse II. Likewise position in the canopy influenced the frequency of some species. The implications for natural biological control are discussed.Centro de Investigaciones de Fitopatologí
Accurate characterization of weak macromolecular interactions by titration of NMR residual dipolar couplings: application to the CD2AP SH3-C:ubiquitin complex
The description of the interactome represents one of key challenges remaining for structural biology. Physiologically important weak interactions, with dissociation constants above 100 μM, are remarkably common, but remain beyond the reach of most of structural biology. NMR spectroscopy, and in particular, residual dipolar couplings (RDCs) provide crucial conformational constraints on intermolecular orientation in molecular complexes, but the combination of free and bound contributions to the measured RDC seriously complicates their exploitation for weakly interacting partners. We develop a robust approach for the determination of weak complexes based on: (i) differential isotopic labeling of the partner proteins facilitating RDC measurement in both partners; (ii) measurement of RDC changes upon titration into different equilibrium mixtures of partially aligned free and complex forms of the proteins; (iii) novel analytical approaches to determine the effective alignment in all equilibrium mixtures; and (iv) extraction of precise RDCs for bound forms of both partner proteins. The approach is demonstrated for the determination of the three-dimensional structure of the weakly interacting CD2AP SH3-C:Ubiquitin complex (Kd = 132 ± 13 μM) and is shown, using cross-validation, to be highly precise. We expect this methodology to extend the remarkable and unique ability of NMR to study weak protein–protein complexes
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