Further analysis of the connected moments expansion

We apply the connected moments expansion to simple quantum--mechanical examples and show that under some conditions the main equations of the approach are no longer valid. In particular we consider two--level systems, the harmonic oscillator and the pure quartic oscillator.Comment: 19 pages; 2 tables; 4 figure

Accurate calculation of the eigenvalues of non-uniforms strings and membranes

We describe a pseudospectral approach which combines a mapping procedure with the principle of minimal sensitivity to obtain accurate estimates for the eigenvalues of non-uniform strings and both uniform and nonuniform membranes. We illustrate the method on specific examples, including the case of a cross shaped membrane, with arms of infinite length.Fil: Amore, P.. Universidad de Colima; MéxicoFil: Fernández, Francisco Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Rodriguez, M.. Universidad de Colima; Méxic

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)$_{C} \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)_{Y^\prime}$. 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

Ancient mitochondrial pseudogenes reveal hybridization between distant lineages in the evolution of the Rupicapra genus

© The Author(s), 2017. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gene 628 (2017): 63-71, doi:10.1016/j.gene.2017.07.035.Mitochondrial pseudogenes (numts) inserted in the nuclear genome are frequently found in population studies. Its presence is commonly connected with problems and errors when they are confounded with true mitochondrial sequences. In the opposite side, numts can provide valuable phylogenetic information when they are copies of ancient mitochondrial lineages. We show that Rupicapra individuals of different geographic origin from the Cantabrian Mountains to the Apennines and the Caucasus share a nuclear COI fragment. The numt copies are monophyletic, and their pattern of differentiation shows two outstanding features: a long evolution as differentiated true mitochondrial lineage, and a recent integration and spread through the chamois populations. The COI pseudogene is much older than the present day mitochondrial clades of Rupicapra and occupies a basal position within the Rupicapra-Ammotragus- Arabitragus node. Joint analysis of this numt and a cytb pseudogene with a similar pattern of evolution places the source mitochondrial lineage as a sister branch that separated from the Ammotragus-Arabitragus lineage 6 million years ago (Mya). The occurrence of this sequence in the nucleus of chamois suggests hybridization between highly divergent lineages. The integration event seems to be very recent, more recent than the split of the present day mtDNA lineages of Rupicapra (1.9 Mya). This observation invites to think of the spread across the genus by horizontal transfer through recent male-biased dispersal.This work was funded by Ministerio de Economía y Competitividad. Spain. (Grant number CGL2011-25117).2018-07-1

Genomic Evolution of Two Acinetobacter baumannii Clinical Strains from ST-2 Clones Isolated in 2000 and 2010 (ST-2_clon_2000 and ST-2_clon_2010)

Acinetobacter baumannii is a successful nosocomial pathogen due to its ability to persist in hospital environments by acquiring mobile elements such as transposons, plasmids, and phages. In this study, we compared two genomes of A. baumannii clinical strains isolated in 2000 (ST-2_clon_2000) and 2010 (ST-2_clon_2010) from GenBank project PRJNA308422

Molecular simulation of methane hydrate growth confined into a silica pore

Financiaciado para publicación en acceso aberto: Universidade de Vigo/CISUGThe growth of a methane hydrate seed within a silica slit pore of fixed width has been studied using All- Atom Molecular Dynamics (AA-MD). An AA force field has been used to describe the molecules of the solid silica substrate, with a-quartz crystalline structure. The crystallisation of hydrates in confined geometries is not well understood yet, and the objective of this work is to study the hydrate growth inside a silica pore using molecular simulation. Both NVT and NpT ensembles were used in the AA-MD simulations to analyse the hydrate growth from an initial seed. Results showed that the boundary conditions imposed by the nanometric slit pore yielded a hydrate with structural defects, filling the accessible space between the silica walls. The water molecules which were not incorporated to the initial seed hydrate formed a high density water layer trapped between the silica walls and the crystallised hydrate. These results provide an interesting insight into the hydrate crystallisation process in confined geometries, resembling those found in natural hydrate deposits.Ministerio de Ciencia e Innovación | Ref. PID2021-125081NB-I00FEDER | Ref. SOE2/P1/P0823Xunta de Galicia | Ref. FSE-GALICIA 2014–2020Fundação para a Ciência e a Tecnologia | Ref. UIDB/50011/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/50011/2020Fundação para a Ciência e a Tecnologia | Ref. LA/ P/0006/2020Ministerio de Ciencia e Innovación | Ref. PID2019-105898GA-C22Comunidad de Madrid | Ref. APOYOJOVENES- 01HQ1S-129-B5E4M

Spondyloarthropathies in Autoimmune Diseases and Vice Versa

Polyautoimmunity is one of the major clinical characteristics of autoimmune diseases (ADs). The aim of this study was to investigate the prevalence of ADs in spondyloarthropathies (SpAs) and vice versa. This was a two-phase cross-sectional study. First, we examined the presence of ADs in a cohort of patients with SpAs (N = 148). Second, we searched for the presence of SpAs in a well-defined group of patients with ADs (N = 1077) including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and Sjögren's syndrome (SS). Among patients with SpAs, ankylosing spondylitis was observed in the majority of them (55.6%). There were two patients presenting with SS in the SpA group (1.4%) and 5 patients with autoimmune thyroiditis (3.5%). The global prevalence of ADs in SpAs was 4.86%. In the ADs group, there were 5 patients with SpAs (0.46%). Our results suggest a lack of association between SpAs and ADs. Accordingly, SpAs might correspond more to autoinflammatory diseases rather than to ADs

Incisivo lateral superior con dos raíces y dos conductos. Caso Clínico.

Las anomalías en la morfología del incisivo lateral superior son de muy baja frecuencia. Las anomalías de desarrollo radicular pueden presentarse como alteraciones tanto en el número de conductos, como en el número de raíces, así como en ambas regiones a la vez. En el presente trabajo, se reporta el caso de un paciente que se presenta a la consulta con malestar en el incisivo lateral superior izquierdo. En la radiografía preoperatoria se detectó la presencia de dos conductos y dos raíces, sin anomalía morfológica de su corona clínica, con requerimiento de tratamiento endodóntico. Concluimos que una correcta interpretación de las imágenes radiográficas preoperatorias es esencial, para poder detectar estas variantes y tomar las consideraciones necesarias para el adecuado tratamiento endodóntico.Fil: Martinez, P.. Universidad de Buenos Aires. Facultad de Odontología; Argentina;Fil: Boldo, M.. Universidad de Buenos Aires. Facultad de Odontología; Argentina;Fil: Corominola, P.. Universidad de Buenos Aires. Facultad de Odontología; Argentina;Fil: Sierra, L.. Universidad de Buenos Aires. Facultad de Odontología; Argentina;Fil: Lenarduzzi, A.. Universidad de Buenos Aires. Facultad de Odontología; Argentina;Fil: Fernández Solari, Jose Javier. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; Argentina;Fil: Rodriguez, P.. Universidad de Buenos Aires. Facultad de Odontología; Argentina

Validation of a Microwave-Assisted Derivatization Gas Chromatography-Mass Spectrometry Method for the Quantification of 2-Hydroxybutyrate in Human Serum as an Early Marker of Diabetes Mellitus

Circulating levels of 2-hydroxybutyrate (2HB) are highly related to glycemic status in different metabolomic studies. According to recent evidence, 2HB is an early biomarker of the future development of dysglycemia and type 2 diabetes mellitus and may be causally related to the progression of normal subjects to impaired fasting glucose or insulin resistance. In the present study, we developed and validated a simple, specific and sensitive gas chromatography-mass spectrometry (GC-MS) method specifically intended to quantify serum levels of 2HB. Liquid-liquid extraction with ethyl acetate was followed by 2 min of microwave-assisted derivatization. The method presented acceptable accuracy, precision and recovery, and the limit of quantification was 5 µM. Levels of 2HB were found to be stable in serum after three freeze-thaw cycles, and at ambient temperature and at a temperature of 4 °C for up to 24 h. Extracts derivatized under microwave irradiation were stable for up to 96 h. No differences were found in 2HB concentrations measured in serum or plasma EDTA samples. In summary, the method is useful for a rapid, precise and accurate quantification of 2HB in serum samples assessed for the evaluation of dysglycemia and diabetes mellitus