335 research outputs found
Neutrino mixing and masses in a left-right model with mirror fermions
In the framework of a left-right model containing mirror fermions with gauge
group SU(3),
we estimate the neutrino masses, which are found to be consistent with their
experimental bounds and hierarchy. We evaluate the decay rates of the Lepton
Flavor Violation (LFV) processes , and . We obtain upper limits for the
flavor-changing branching ratios in agreement with their present experimental
bounds. We also estimate the decay rates of heavy Majorana neutrinos in the
channels , and , which are roughly equal for large values of the heavy
neutrino mass. Starting from the most general Majorana neutrino mass matrix,
the smallness of active neutrino masses turns out from the interplay of the
hierarchy of the involved scales and the double application of seesaw
mechanism. An appropriate parameterization on the structure of the neutrino
mass matrix imposing a symmetric mixing of electron neutrino with muon and tau
neutrinos leads to Tri-bimaximal mixing matrix for light neutrinos.Comment: Accepted by European Physical Journal
Arginine-rich peptides destabilize the plasma membrane, consistent with a pore formation translocation mechanism of cell penetrating peptides
Recent molecular dynamics simulations (Herce and Garcia, PNAS, 104: 20805
(2007)) have suggested that the arginine-rich HIV Tat peptides might be able to
translocate by destabilizing and inducing transient pores in phospholipid
bilayers. In this pathway for peptide translocation, arginine residues play a
fundamental role not only in the binding of the peptide to the surface of the
membrane but also in the destabilization and nucleation of transient pores
across the bilayer, despite being charged and highly hydrophilic. Here we
present a molecular dynamics simulation of a peptide composed of nine arginines
(Arg-9) that shows that this peptide follows the same translocation pathway
previously found for the Tat peptide. We test this hypothesis experimentally by
measuring ionic currents across phospholipid bilayers and cell membranes
through the pores induced by Arg-9 peptides. We find that Arg-9 peptides, in
the presence of an electrostatic potential gradient, induce ionic currents
across planar phospholipid bilayers, as well as in cultured osteosarcoma cells
and human smooth muscle cells freshly isolated from the umbilical artery. Our
results suggest that the mechanism of action of Arg-9 peptide involves the
creation of transient pores in lipid bilayers and cell membranes.Comment: This is an extended version of the published manuscript, which had to
be shortened before publication to fit within the number of pages required by
the journa
Neutrino masses and mixing parameters in a left-right model with mirror fermions
In this work we consider a left-right model containing mirror fermions with
gauge group SU(3). The model has several free parameters which here we have
calculated by using the recent values for the squared-neutrino mass
differences. Lower bound for the mirror vacuum expectation value helped us to
obtain crude estimations for some of these parameters. Also we estimate the
order of magnitude of the masses of the standard and mirror neutrinos.Comment: 13 pages, version submitted to European Physical Journal
Antimicrobial resistance through the lens of one health in Ethiopia: a review of the literature among humans, animals, and the environment
OBJECTIVES: We aimed to review and describe antimicrobial resistance (AMR) prevalence in humans, animals, and the environment in Ethiopia. METHODS: We conducted a structured review of the literature on AMR in humans, animals, and the environment in Ethiopia from 2016 to 2020. We reported the pooled prevalence of AMR of bacterial pathogens in all three sectors. RESULTS: We included 43 articles in our review. Only five studies evaluated AMR across multiple sectors. The most common bacteria in humans were Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. High prevalence of resistance to third-generation cephalosporins, fluoroquinolones, and sulfamethoxazole-trimethoprim were seen in gram-negative organisms, often with >50% prevalence of resistance. Highest resistance rates were seen in humans, followed by environmental isolates. Salmonella spp. exhibited higher rates of resistance than previously reported in the literature. We found methicillin-resistant S. aureus (MRSA) in approximately half of S. aureus from the environment and a third from human isolates. Few studies evaluated AMR across all three sectors. CONCLUSION: Our review demonstrated high prevalence of AMR among bacteria in humans, animals, and the environment in Ethiopia. Integrating a One Health approach into AMR surveillance as part of Ethiopia's national surveillance program will inform future implementation of One Health interventions
Newton-Hooke/Carrollian expansions of (A)dS and Chern-Simons gravity
We construct finite- and infinite-dimensional non-relativistic extensions of the Newton-Hooke and Carroll (A)dS algebras using the algebra expansion method, starting from the (anti-)de Sitter relativistic algebra in D dimensions. These algebras are also shown to be embedded in different affine Kac-Moody algebras. In the three-dimensional case, we construct Chern-Simons actions invariant under these symmetries. This leads to a sequence of non-relativistic gravity theories, where the simplest examples correspond to extended Newton-Hooke and extended (post-)Newtonian gravity together with their Carrollian counterparts
Efficiency of Combined Processes Coagulation/Solar Photo Fenton in the Treatment of Landfill Leachate
The combined coagulation-solar photo Fenton treatment of leachate from the sanitary landfill located in Atlantico-Colombia was investigated. Firstly, the efficiency of two alternative combined treatments for the reduction of chemical oxygen demand in leachate was assessed, coagulation with poly-aluminum chloride followed by solar photo-Fenton process (Treatment 1) and coagulation with FeCl3·6H2O followed by ferrioxalate-induced solar photo-Fenton process (Treatment 2). Afterwards, treatments 1 and 2 were compared with the treatment currently used in the sanitary landfill (only coagulation with poly-aluminum chloride), in terms of efficiency and costs. An optimization study of alternative treatments was performed combining central-composite experimental design and response surface methodology. The optimum conditions resulted in a chemical oxygen demand reduction of 73 % and 80 % for Treatment 1 and 2, respectively. Both alternative treatments for the leachate are more efficient than the treatment currently used in the sanitary landfill (chemical oxygen demand reduction of 20 %). In terms of costs, treatment 1 would be the most competitive to implement in the sanitary landfill, since this would have an increase of 13.3 % in the total unitary cost compared to an increase of 39.5 % of treatment 2
Behavioral Variant Frontotemporal Lobar Degeneration with Amyotrophic Lateral Sclerosis with a Chromosome 9p21 Hexanucleotide Repeat
To determine the genetic basis of familial frontotemporal lobar degeneration (FTLD) with amyotrophic lateral sclerosis (ALS) we performed a clinical and genetic analysis of an affected family. A 51-year-old man with behavioral variant FTLD with ALS had a family history of the disease suggestive of autosomal dominant inheritance with incomplete penetrance. Genetic studies in this patient demonstrated the presence of an amplified hexanucleotide repeat (>30) polymorphism in the chromosome 9 open reading frame 72 (C9ORF72) gene which was previously identified as a cause of FTLD. Five others unaffected from the family were negative (all had less than 11 repeats). Because of the clinical and pathological overlap between FTLD and AD we performed a larger genome-wide association study and did not find association of single nucleotide polymorphisms (SNPs) in the C9ORF72 gene with Alzheimer’s disease (AD) risk. Bioinformatic analysis of C9ORF72 using the Gene Expression Omnibus database showed expression differences in patients with muscular dystrophy, neural tube defects, and schizophrenia. We also report analysis of gene expression in brain regions using the Allen Human Brain Atlas. Defects in this recently reported gene are now believed to be the most common cause of inherited ALS and an important cause of inherited FTLD. Our work suggests that the gene may also be important in other neurological and psychiatric conditions
Building process of industrial chimneys of brick in Valencia and Murcia
[ES] A partir de entrevistas realizadas a distintos maestros constructores de chimeneas industriales de ladrillo, pertenecientes
a las escuelas valenciana y murciana, que recurren a estilos y sistemas de ejecución muy diferentes, se ha procedido a describir
los sistemas empleados en España para la construcción de estos monolitos industriales.
Los sistemas abordados implementan los conocimientos de la Historia de la Construcción española, con un elemento que
tuvo una corta vida, pero que fue esencial en la evolución industrial y son clave a la hora de enfrentarnos a una posible
restauración del elemento.[EN] The system used in Spain for the construction of industrial brick chimneys in east and south east of Spain and those that
have been its influence is described in this paper, from interviews with different master builders belonging to the Valencia
and Murcia schools, with styles and systems of very different execution.
The addressed systems implement the knowledge of the Spanish Construction History, of an item that had a short life
though it was essential in industrial development and becomes the key for a possible restoration of the element.López Patiño, MG.; Verdejo Gimeno, P.; Martínez Antón, A.; Benlloch Marco, J. (2016). Proceso de ejecución de chimeneas industriales de ladrillo valencianas y murcianas. Informes de la Construcción. 68(543):1-10. doi:10.3989/ic.15.068S11068543(1) Valdés, N. (1870). Manual del ingeniero y arquitecto. Madrid: Imprenta de Gabriel Alhambra.(2) Rebolledo, J.A. (1875). Construcción general. Madrid: Imprenta y Fundición de J. Antonio García.(3) Wilson, R. (1877). Boiler and factory chimneys, their draught-power and stability. London: Crosby Lockwood & Co.(4) Buchanan, R. (1850). An account of the chimney of the Edimburg Gas Works, with observations on the principles of its strenght and stability. Civil Engineers and Architects Journal.(6) Bancroft, R.M., Bancroft F.J. (1885). A practical treatise on the construction of Tall chimney Shafts. Manchester: John Calvert
Susceptibility of biological stages of the horn fly, Haematobia irritans, to entomopathogenic fungi (Hyphomycetes)
The susceptibility of the egg, pupa, and adult of Haematobia irritans (L.) (Diptera: Muscidae) to isolates of the fungi Metarhizium anisopliae (Metsch.) Sor., Beauveria bassiana (Bals.) Vuill., and Paecilomyces fumosoroseus (Wize) Brown and Smith, was evaluated under laboratory conditions. Groups of 20 eggs than 4 h old, pupae less than 48h old and adults were sprayed with a conidial suspension of each isolate. Eggs, pupae and adults of horn fly were susceptible to these entomopathogenic fungi. For treated eggs, the isolates Ma3, Ma 15, Ma25, Pfr1, and Pfr8 reduced adult emergence to 3.8% to 6.3% in comparison with the control (72%). The mortality of pupae infected by the isolates Ma2, Ma25, and Pfr10 ranged between 50% and 71.3%. Mortality of adults after treatment with the isolates Ma6, Ma 10, Ma 14, Ma 15, Pfr 1, Pfr 9, Pfr 10, Pfr 11, and Pfr12 were higher than 90%. The isolate Ma6 produced the lowest LC(50) against adult horn flies (8.08 × 10(2)conidia/ml). These findings supported the hypotheses that isolates of M. anisopliae, and P. fumosoroseus are pathogenic against the different biological stages of horn flies by reducing adult emergence when applied on groups of eggs and pupae, and producing mortality when applied to adults
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