68 research outputs found
Electron-positron annihilation into phi f_{0}(980) and clues for a new 1^{--} resonance
We study the e^{+}e^{-} to phi pi pi reaction for pions in an isoscalar
s-wave which is dominated by loop mechanisms. For kaon loops we start from the
conventional RCHPT, but use the unitarized amplitude for KbarK-pipi scattering
and the full kaon form factor instead of the lowest order terms. We study also
effects of vector mesons using RCHPT supplemented with the conventional
anomalous term for VVP interactions and taking into account the effects of
heavy vector mesons in the K*K transition form factor. We find a peak in the
dipion invariant mass around the f_{0}(980) as in the experiment. Selecting the
phi f_{0}(980) contribution as a function of the e^{+}e^{-} energy we also
reproduce the experimental data except for a narrow peak, yielding support to
the existence of a 1^{--} resonance above the phi f_{0}(980) threshold,
coupling strongly to this state.Comment: 18 pages, 4 figure
Predictive Pati-Salam theory of fermion masses and mixing
We propose a Pati-Salam extension of the standard model incorporating a
flavor symmetry based on the group. The theory
realizes a realistic Froggatt-Nielsen picture of quark mixing and a predictive
pattern of neutrino oscillations. We find that, for normal neutrino mass
ordering, the atmospheric angle must lie in the higher octant, CP must be
violated in oscillations, and there is a lower bound for the
decay rate. For the case of inverted mass ordering, we find that the lower
atmospheric octant is preferred, and that CP can be conserved in oscillations.
Neutrino masses arise from a low-scale seesaw mechanism, whose messengers can
be produced by a portal at the LHC.Comment: 28 pages, 3 figures, published versio
Simple theory for scotogenic dark matter with residual matter-parity
Dark matter stability can result from a residual matter-parity symmetry
surviving spontaneous breaking of an extended gauge symmetry. We propose the
simplest scotogenic dark matter completion of the original SVS theory
(Phys.Rev. D22 (1980) 738), in which the "dark sector" particles as well as
matter-parity find a natural theoretical origin in the model. We briefly
comment on its main features.Comment: 14 pages, 2 figures. Matches published version in PL
Neutrino predictions from a left-right symmetric flavored extension of the standard model
We propose a left-right symmetric electroweak extension of the Standard Model
based on the family symmetry. The masses of all
electrically charged Standard Model fermions lighter than the top quark are
induced by a Universal Seesaw mechanism mediated by exotic fermions. The top
quark is the only Standard Model fermion to get mass directly from a tree level
renormalizable Yukawa interaction, while neutrinos are unique in that they get
calculable radiative masses through a low-scale seesaw mechanism. The scheme
has generalized symmetry and leads to a restricted range of neutrino
oscillations parameters, with a nonzero neutrinoless double beta decay
amplitude lying at the upper ranges generically associated to normal and
inverted neutrino mass ordering.Comment: 20 pages, 4 figures. Published versio
Tropical Grass Growth Functions Modeling by Using Nonlinear Mixed Models
Nonlinear Growth curves are used for modeling plant physiological variables. These models are preferable because the polynomial coefficients of the equations have a biological significance. The response variables of the curves occurs commonly with repeated measurements over time and measurements are on different environments. The traditional statistical analysis does not include a repeated measures approach, which can lead to improper estimation of the error terms. It is important to study the growth of tropical grass (Da Silva and Carvalho 2005)
Human IFIT1 inhibits mRNA translation of rubulaviruses but not other members of the Paramyxoviridae family
This work was supported by The Welcome Trust (101788/Z/13/Z, 101792/Z/13/Z) and Medical research council grant (G1100110/1, MR/K024213/1).We have previously shown that IFIT1 is primarily responsible for the antiviral action of interferon (IFN) alpha/beta against parainfluenza virus (PIV) type 5, selectively inhibiting the translation of PIV5 mRNAs. Here we report that whilst PIV2, PIV5 and mumps virus (MuV) are sensitive to IFIT1, non-rubulavirus members of the paramyxoviridae such as PIV3, Sendai virus (SeV) and canine distemper virus (CDV) are resistant. The IFIT1-sensitivity of PIV5 was not rescued by co-infection with an IFIT1-resistant virus (PIV3), demonstrating that PIV3 does not specifically inhibit the antiviral activity of IFIT1 and that the inhibition of PIV5 mRNAs is regulated by cis-acting elements. We developed an in vitro translation system using purified human IFIT1 to further investigate the mechanism of action of IFIT1. Whilst the translation of PIV2, PIV5 and MuV mRNAs were directly inhibited by IFIT1, the translation of PIV3, SeV and CDV mRNAs were not. Using purified human mRNA capping enzymes we show biochemically that efficient inhibition by IFIT1 is dependent upon a 5’ guanosine nucleoside cap (which need not be N7-methylated) and that this sensitivity is partly abrogated by 2’ O methylation of the cap 1 ribose. Intriguingly, PIV5 M mRNA, in contrast to NP mRNA, remained sensitive to inhibition by IFIT1 following in vitro 2’ O methylation, suggesting that other structural features of mRNAs may influence their sensitivity to IFIT1. Thus, surprisingly, the viral polymerases (which have 2’ -O-methyltransferase activity) of rubulaviruses do not protect these viruses from inhibition by IFIT1. Possible biological consequences of this are discussed. Importance Paramyxoviruses cause a wide variety of diseases and yet most of their genes encode for structural proteins and proteins involved in their replication cycle. Thus the amount of genetic information that determines the type of disease paramyxoviruses cause is relatively small. One factor that will influence disease outcomes is how they interact with innate host cell defences, including the interferon (IFN) system. Here we show that different paramyxoviruses interact in distinct ways with cells in a pre-existing IFN-induced antiviral state. Strikingly, all the rubulaviruses tested were sensitive to the antiviral action of ISG56/IFIT1, whilst all the other paramyxoviruses tested were resistant. We developed novel in vitro biochemical assays to investigate the mechanism of action of IFIT1, demonstrating that the mRNAs of rubulaviruses can be directly inhibited by IFIT1 and that this is at least partially because their mRNAs are not correctly methylated.Publisher PDFPeer reviewe
Occupational and Environmental Risks from Mancozeb in Aviation Facilities in the Banana Producing Area of Teapa, Tabasco, Mexico
Purpose: To identify occupational risks and practices in the four aerial fumigation facilities in the Sierra banana growing region and to evaluate environmental impacts from Mancozeb use.Methods: Occupational health risks were identified and practices in the four aerial fumigation facilities in the Sierra banana growing region were documented. Semi-structured interviews were conducted with installation managers. To evaluate environmental impact, samples of water and soil were collected and analysed in an acute toxicity bioassay with Vibrio fischeri, using uncontaminated soil and water to establish background levels.Results: Even in the largest and best-equipped facility, serious risks to workers’ health were encountered from inadequate use of protective equipment by workers. Furthermore, excessive use of pesticide, lack of re-use of unused product, poor facility design and poor use of wash-water were observed, resulting in maximum toxicity of > 5 times background in discharged water. Parallel soil samples were > 20 times more toxic than background, being most toxic at > 0.5 km from the discharge point.Conclusion: Areas of opportunity to improve worker health and the environment include proper and consistent use of protective equipment, re-use of unused product, wastewater reduction and appropriate wastewater treatment.Keywords: Black Sigatoka, Ethylene thiourea, Fumigation, Pesticide, Mancozeb, Airports, Microtox, Vibrio fischeri, Occupational health risks, Toxicit
Ecosystem-bedrock interaction changes nutrient compartmentalization during early oxidative weathering
Ecosystem-bedrock interactions power the biogeochemical cycles of Earth's
shallow crust, supporting life, stimulating substrate transformation, and
spurring evolutionary innovation. While oxidative processes have dominated half
of terrestrial history, the relative contribution of the biosphere and its
chemical fingerprints on Earth's developing regolith are still poorly
constrained. Here, we report results from a two-year incipient weathering
experiment. We found that the mass release and compartmentalization of major
elements during weathering of granite, rhyolite, schist and basalt was
rock-specific and regulated by ecosystem components.
A tight interplay between physiological needs of different biota, mineral
dissolution rates, and substrate nutrient availability resulted in intricate
elemental distribution patterns. Biota accelerated CO2 mineralization over
abiotic controls as ecosystem complexity increased, and significantly modified
stoichiometry of mobilized elements. Microbial and fungal components inhibited
element leaching (23.4% and 7%), while plants increased leaching and biomass
retention by 63.4%. All biota left comparable biosignatures in the dissolved
weathering products. Nevertheless, the magnitude and allocation of weathered
fractions under abiotic and biotic treatments provide quantitative evidence for
the role of major biosphere components in the evolution of upper continental
crust, presenting critical information for large-scale biogeochemical models
and for the search for stable in situ biosignatures beyond Earth.Comment: 41 pages (MS, SI and Data), 16 figures (MS and SI), 6 tables (SI and
Data). Journal article manuscrip
Can Complex Training Improve Acute and Long-Lasting Performance in Basketball Players? A Systematic Review
Basketball demands a sophisticated blend of tactical, technical, physical, and psychological skills, and various methods have been proposed to prepare players for these demands, including resistance training to enhance strength, power, speed, agility, and endurance. Complex training (CT) integrates diverse strength training methodologies by combining heavy-resistance exercises (e.g., squat at 90% of one repetition maximum) with high-velocity movements or plyometrics, both sharing the same biomechanical pattern. However, the optimal application of CT in basketball remains uncertain due to diverse protocols and a lack of consensus in the literature. The aim of this systematic review was to evaluate the acute and chronic effects of CT interventions on physical fitness performance in basketball players and identify the most effective characteristics of moderators. Methods: A bibliographic search was conducted using PubMed, SCOPUS, and Web of Science databases following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines using the PICOS strategy. Results: Fourteen studies met the inclusion criteria, three articles analyzed acute effects, and thirteen analyzed chronic effects. The total number of participants in the studies analyzing acute effects was 50, while for studies examining chronic effects, it was 362. Conclusions: Acutely, CT triggers post-activation potentiation and enhances sprint performance when coupled with brief rest intervals. Over time, these acute improvements contribute to more substantial, long-lasting benefits. Chronic effects of CT improve strength, as evidenced by enhanced 1 RM performance, jumps, sprints, and core muscle strength
Photo- and Electron-Production of Mesons on Nucleons and Nuclei
In these lectures I will show some results obtained with the chiral unitary
approach applied to the photo and electroproduction of mesons. The results for
photoproduction of and , together with
related reactions will be shown, having with common denominator the excitation
of the resonance which is one of those dynamically generated in
the chiral unitary approach. Then I will show results obtained for the reaction which reproduce the bulk of the data except for a
pronounced peak, giving support to a new mesonic resonance, X(2175). Results
will also be shown for the electromagnetic form factors of the
resonance, also dynamically generated in this approach. Finally, I will show
some results on the photoproduction of the in nuclei, showing that
present experimental results claiming a shift of the mass in the
medium are tied to a particular choice of background and are not conclusive.
One the other hand, the same experimental results show unambiguously a huge
increase of the width in the nuclear medium.Comment: Lecture at the "International School of Nuclear Physics", 29th Course
Quarks in Hadrons and Nuclei, Erice, Italy, September 2007. Note added in
Proofs concerning the mixed events technique and other comments on omega
productio
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