1,530 research outputs found

    Entanglement and quantum phase transition in the one-dimensional anisotropic XY model

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    In this paper the entanglement and quantum phase transition of the anisotropic s=1/2 XY model are studied by using the quantum renormalization group method. By solving the renormalization equations, we get the trivial fixed point and the untrivial fixed point which correspond to the phase of the system and the critical point, respectively. Then the concurrence between two blocks are calculated and it is found that when the number of the iterations of the renormalziation trends infinity, the concurrence develops two staturated values which are associated with two different phases, i.e., Ising-like and spin-fluid phases. We also investigate the first derivative of the concurrence, and find that there exists non-analytic behaviors at the quantum critical point, which directly associate with the divergence of the correlation length. Further insight, the scaling behaviors of the system are analyzed, it is shown that how the maximum value of the first derivative of the concurrence reaches the infinity and how the critical point is touched as the size of the system becomes large.Comment: 10 pages, 5 figure

    Tratamiento quirúrgico en las cifosis congénitas: Revisión de 14 pacientes

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    Los autores efectúan una revisión de 14 pacientes con cifosis congénita, intervenidos entre los años 1979-1989, con un seguimiento medio de 7 años. La edad media preoperatoria fue de 11 años (todos ellos mayores de 5 años), con una cifosis media de 7 9 . En 6 casos se realizó una artrodesis posterior y en 8 una anterior combinada con una fusión posterior. Inicialmente obtuvieron una corrección media de la curva de 18° con la artrodesis posterior y 20° con la artrodesis combinada. La pérdida postoperatoria final fue de 10° y 8° respectivamente. En un caso, se produjo una pseudoartrosis por fusión corta. Como complicaciones postoperatorias en 5 pacientes, una radiculopatía, una infección superficial y cuatro protusiones de material que requirieron su extracción. Los autores analizan los factores que han podido influir en los resultados obtenidos, comparándolos posteriormente con los conseguidos por otros centros hospitalarios importantes.Fourteen patients with congenital kyphosis treated surgically between 1979- 1989 were reviewed. All had a follow-up of 2 years or more, with an average follow-up of 7 years. The average age at surgery was 11 and the average kyphosis was 79°. Six cases had posterior fusion only and eigth had combined anterior and posterior fusion. The results showed an average correction of the curve at surgery of 18° with posterior arthrodesis and 20° with combined arthrodesis. There was thus an average loss of 10° and 8° respectively from the time of surgery in both types of treatment. Pseudoarthrosis by short fusion ocurred in one case. Other complications after surgery were 1 radiculopathy, one wound infection and four rod protusion (six patients). The factors that have influence in this results were analysed. A comparison from the results of treatment at other medical centers was also carried out

    Clinical Study of Memory Disorders in Aging Patients with Associated Cardiovascular, Neurological, Neurobehavioral and Metabolic Diseases”. A Review

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    We have observed semantic memory and episodic memory disorders (100%) in patients ranging from 40 to 92 years-old, associated to cardiovascular diseases and blood hypertension (82%), sleep disorders (50%), neurobehavioral disorders (44%), such as depression, anxiety, aggression, and vascular demencia, disorders of language (36%), neurosensory disorders (28%), as diminution of visual and hearing acuity, dizziness (26%), Parkinson disease (34%), Alzheimer disease (21%), gait disturbances (10%), vertigo (10%), cervicalgia and cervicogenic headache (10%) trigeminal neuralgia (2%,), We observed as comorbidities the following non-nervous diseases: metabolic diseases as diabetes (21%) and hypothyroidism (5%), gastrointestinal pathology (21%), such as constipation, loss of sphincter control, and gastritis, arthritis (13%), prostatic hypertrophy (1%) and loss of weight (1%). We consider that according to their high frequency the most risk factors associated to memory disorders are cardiovascular diseases and blood hypertension (82%), sleep disorders (50%), neurobehavioral disorders (44%), such as depression, anxiety, aggression, and vascular demencia, disorders of language (36%), neurosensory disorders (28%), as diminution of visual and hearing acuity, dizziness (26%), and Parkinson disease (34%)

    Micro-tomographic characterization of the root and canal system morphology of mandibular first premolars in a Chilean population

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    Indexación ScopusThis study aimed to analyze the root anatomy and root canal system morphology of mandibular first premolars in a Chilean population. 186 teeth were scanned using micro-computed tomography and reconstructed three-dimensionally. The root canal system morphology was classified using both Vertucci’s and Ahmed’s criteria. The radicular grooves were categorized using the ASUDAS system, and the presence of Tomes’ anomalous root was associated with Ahmed’s score. A single root canal was identified in 65.05% of teeth, being configuration type I according to Vertucci’s criteria and code 1MP1 according to Ahmed’s criteria. Radicular grooves were observed in 39.25% of teeth. The ASUDAS scores for radicular grooves were 60.75%, 13.98%, 12.36%, 10.22%, 2.15%, and 0.54%, from grade 0 to grade 5, respectively. The presence of Tomes’ anomalous root was identified only in teeth with multiple root canals, and it was more frequently associated with code 1MP1–2 of Ahmed’s criteria. The root canal system morphology of mandibular first premolars showed a wide range of anatomical variations in the Chilean population. Teeth with multiple root canals had a higher incidence of radicular grooves, which were closely related to more complex internal anatomy. Only teeth with multiple root canals presented Tomes’ anomalous root. © 2021, The Author(s).https://www-nature-com.recursosbiblioteca.unab.cl/articles/s41598-020-80046-

    Evolution and Biogeographic History of Rubyspot Damselflies (Hetaerininae: Calopterygidae: Odonata)

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    The damselflies Hetaerininae, a subfamily of Calopterygidae, comprise four genera distributed from North to South America: Hetaerina, Mnesarete, Ormenophlebia and Bryoplathanon. While several studies have focused on the intriguing behavioral and morphological modifications within Hetaerina, little of the evolutionary history of the group is well understood. Understanding the biogeographical history of Hetaerininae is further complicated by uncertainty in important geological events, such as the closure of the Central American Seaway (CAS). We generated a phylogenetic hypothesis to test the relationships and divergence times within Hetaerininae using IQtree and BEAST2 and found that Mnesarete and Ormenophlebia render Hetaerina paraphyletic. Reclassification of the genera within Hetaerininae is necessary based on our results. We also tested the fit to our dataset of two different hypotheses for the closure of CAS. Our results supported a gradual closure, starting in the Oligocene and ending in the Pliocene. Using Ancestral Character State Reconstruction, we found that the rubyspot, which is associated with higher fecundity in several species, was ancestral for Hetaerininae and subsequently lost four times. Estimates of diversification in association with the rubyspot are needed to understand the plasticity of this important character. Forest habitat was the ancestral state for Hetaerininae, with transitions to generalist species of Hetaerina found primarily in the Mesoamerican region. These results add to our understanding of the relationship between morphology, biogeography and habitat in a charismatic group of damselflie

    Seguridad de la ivermectina: toxicidad y reacciones adversas en diversas especies de mamíferos

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    P. 2129-2137La ivermectina es un fármaco antiparasitario muy utilizado en Medicina Veterinaria, dado su espectro de actividad que abarca tanto endo como ectoparásitos, elevada eficacia y amplio margen de seguridad. No obstante, su administración puede dar lugar a efectos tóxicos. La mayoría de ellos derivan de la sobredosificación del compuesto, aunque también se han descrito, a dosis terapéuticas, casos de susceptibilidad extrema a los efectos neurotóxicos del fármaco en determinadas razas o subpoblaciones de animales, así como reacciones anafilácticas por la destrucción masiva de parásitos.S

    Aspergillus fumigatus Fumagillin Contributes to Host Cell Damage

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    The activity of fumagillin, a mycotoxin produced by Aspergillus fumigatus, has not been studied in depth. In this study, we used a commercial fumagillin on cultures of two cell types (A549 pneumocytes and RAW 264.7 macrophages). This toxin joins its target, MetAP2 protein, inside cells and, as a result, significantly reduces the electron chain activity, the migration, and the proliferation ability on the A549 cells, or affects the viability and proliferation ability of the RAW 264.7 macrophages. However, the toxin stimulates the germination and double branch hypha production of fungal cultures, pointing out an intrinsic resistant mechanism to fumagillin of fungal strains. In this study, we also used a fumagillin non-producer A. fumigatus strain (∆fmaA) as well as its complemented strain (∆fmaA::fmaA) and we tested the fumagillin secretion of the fungal strains using an Ultra High-Performance Liquid Chromatography (UHPLC) method. Furthermore, fumagillin seems to protect the fungus against phagocytosis in vitro, and during in vivo studies using infection of immunosuppressed mice, a lower fungal burden in the lungs of mice infected with the ∆fmaA mutant was demonstrated.This research was funded by the Basque Government: grant number IT1362-19. X.G. and S.C.-S. received a Ph.D. fellowship from the Basque Government; and U.P.-C. from the University of the Basque Country

    STA, the Space Trajectory Analysis Project

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    This article describes the objectives of the Space Trajectory Analysis (STA) project. The article also details the birth of STA, and its present configuration. STA is a project to develop an open source astrodynamics software suite involving university science departments and space research institutions. It was initiated by ESA as internal activity in 2005 and now it involves 16 partners. The article explains the partnership into the STA Steering Board. The main purpose of the STA is to allow advanced simulation for the analysis of space trajectories in an open and free environment under the premises of innovation and reliability.Further, the article explains that the STA development is open source and is based on the state of the art astrodynamics routines that are grouped into modules. Finally, the article concludes about the benefits of the STA initiative: the STA project allows a strong link among applied mathematics, space engineering, and informatics disciplines by reinforcing the academic community with requirements and needs coming from real missions
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