841 research outputs found

    Analysis of Representativeness of the Paramo Ecosystem in the Conservation Modalities of the Chimborazo Province

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    The paramo ecosystem has ecological, social, cultural and economic importance due to the ecosystemic services of supply, regulation, support and culture that it provides to local populations for their well-being, therefore, it needs to be conserved and managed from an ecosystemic approach. The objective of this work is to analyze the conservation modalities that protect the paramo ecosystem in the Chimborazo province. To conduct the research, a systematic review of 30 cartographic sources was carried out, and documentary information on 7 variables of the paramo ecosystem was made, provided by institutions in charge of managing the province's natural resources, and found in articles consulted in scientific and academic databases. Additionally, gray literature has been included through manual search. The results indicate that the Chimborazo province has 17.93% of its extension under conservation modality, through 121 protected natural spaces, distributed in 3 modalities. The paramo ecosystem represents 36.40% of the province's size, and is made up of 9 vegetation formations. 15.10% of this ecosystem are under conservation modality, however, only 3 of the 121 spaces have planning documents for the management of these spaces. Keywords: paramo ecosystem, ecosystem services, conservation modalities. Resumen El ecosistema páramo tiene importancia ecológica, social, cultural y económica por los servicios ecosistémicos de abastecimiento, regulación, soporte y culturales que suministra a las poblaciones locales para su bienestar, por tanto, requiere ser conservado y manejado desde un enfoque ecosistémico. El objetivo de este trabajo es analizar las modalidades de conservación que protegen el ecosistema páramo en la provincia de Chimborazo. Para llevar a cabo la investigación se realizó una revisión sistémica de 30 fuentes de información cartográfica y documental sobre 7 variables del ecosistema páramo, facilitadas por instituciones encargadas del manejo de los recursos naturales de la provincia, y encontradas en artículos consultados en bases de datos científicas y académicas, adicionalmente se ha incluido literatura gris mediante la búsqueda manual. Los resultados indican que la provincia de Chimborazo tiene 17,93% de su extensión bajo modalidad de conservación, a través de 121 espacios naturales protegidos, distribuidos en 3 modalidades. El ecosistema páramo representa el 36,40% de la extensión de la provincia y está conformada por 9 formaciones vegetales. El 15,10% de éste ecosistema se encuentran bajo modalidad de conservación, sin embargo, únicamente 3 de los 121 espacios poseen documentos para el manejo de estos espacios. Palabras clave: ecosistema páramo, servicios ecosistémicos, modalidades de conservación

    Passive odd viscoelasticity

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    Active chiral viscoelastic materials exhibit elastic responses perpendicular to the applied stresses, referred to as odd elasticity. We use a covariant formulation of viscoelasticity combined with an entropy production analysis to show that odd elasticity is not only present in active systems but also in broad classes of passive chiral viscoelastic fluids. In addition, we demonstrate that linear viscoelastic chiral solids require activity in order to manifest odd elastic responses. To model the phenomenon of passive odd viscoelasticity we propose a chiral extension of Jeffreys model. We apply our covariant formalism in order to derive the dispersion relations of hydrodynamic modes and obtain clear imprints of odd viscoelastic behavior

    Running Economy: Reproductibility at submaximal high speed

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    INTRODUCTION: The running economy (RE) has been traditionally determined by measuring the steady-state consumption of oxygen at a specific speed; however few studies has been designed to evaluate the reproductibility of the RE at a high rate of maximum oxygen consumption after repeated submaximal efforts within the same session. PURPOSE: The purpose of this study was valuate if the reproductibility of running economy at submaximal high speed could be affected by two previous submaximal efforts. METHODS: In this study participated 19 subjects (mean±SD; age, 21.8±2.5 years; body mass, 71.0±10.6 and height, 175.2±8.1). During three days of assessment separately for at least 24h of recovery, subjects performed the following tests. Day 1 a maximum incremental test, to determine the intensities. Day 2 a test of running economy at 80% of VO2max. Day 3 a test of running economy at 30, 70 and 80% of VO2max separated by 5 min of recovery. t-student test was conducted to measure test-retest differences in RE the p value were set al ≤0.05. RESULTS: No significant differences were found in the Running Economy at 80% of VO2max determined in both economy tests RE 220.1± 21.6vs 219.6±20.6 (ml·kg-1·km-1), ICC; 0.92, CV; 4.4 ± 2.6. CONCLUSION: The results of the present study showed exercises sessions at 30 and 70 of VO2max performed before the submaximal exercise test (80% of VO2max) did not affected the RE during an exercise test performed at 80% of VO2max

    Reparación del cartílago articular con injerto libre de pericondrio estudio experimental

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    Ante la incapacidad de regeneración espontánea de lesiones profundas y amplias del cartílago articular, estudiamos la reparación cartilaginosa con plastias de pericondrio tomadas de la región condro-costal e implantándolas con su cara condrogénica sobre una lesión osteocondral realizada en la superficie articular rotuliana. Macroscópica e histológicamente, a la octava semana, el neocartílago formado tenía igual apariencia que el cartílago hialino normal, no existiendo separación entre el cartílago remanente y el neoformado a partir de la plastia. Estos resultados corroboran el gran potencial condrogénico del pericondrioFaced with the incapacity of spontaneous regeneration of deep and extensive lesions of the articular cartilage we studied the cartilaginous repair with pericondrium grafts taken from the chondro-costal region. Grafts were implanted with their condrogenic face over an osteochondral defect located at the surface of the patella. At the 8th week, the neocartilage formed had macroscopically and histologically, the same appearance as the normal hyaline cartilage, with no separation between the remaining cartilage and the neocartilage induced by the graft. These results corroborate the high chondrogenic potential of the perichondrium

    The optical counterpart of the bright X-ray transient Swift J1745-26

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    We present a 30-day monitoring campaign of the optical counterpart of the bright X-ray transient Swift J1745-26, starting only 19 minutes after the discovery of the source. We observe the system peaking at i' ~17.6 on day 6 (MJD 56192) to then decay at a rate of ~0.04 mag/day. We show that the optical peak occurs at least 3 days later than the hard X-ray (15-50 keV) flux peak. Our measurements result in an outburst amplitude greater than 4.3 magnitudes, which favours an orbital period < 21 h and a companion star with a spectral type later than ~ A0. Spectroscopic observations taken with the GTC-10.4 m telescope reveal a broad (FWHM ~ 1100 km/s), double-peaked H_alpha emission line from which we constrain the radial velocity semi-amplitude of the donor to be K_2 > 250 km/s. The breadth of the line and the observed optical and X-ray fluxes suggest that Swift J1745-26 is a new black hole candidate located closer than ~7 kpc.Comment: 5 pages, 4 figures, accepted for publication in MNRA

    The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features

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    The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (~90 s), which included a detailed coverage of the most active phase of the event. We present a database consisting of 651 optical spectra obtained during this event, that we combine with 58 spectra gathered during the fainter December 2015 sequel outburst, as well as with 57 spectra from the 1989 event. We previously reported the discovery of wind-related features (P-Cygni and broad-wing line profiles) during both 2015 outbursts. Here, we build diagnostic diagrams that enable us to study the evolution of typical emission line parameters, such as line fluxes and equivalent widths, and develop a technique to systematically detect outflow signatures. We find that these are present throughout the outburst, even at very low optical fluxes, and that both types of outflow features are observed simultaneously in some spectra, confirming the idea of a common origin. We also show that the nebular phases depict loop patterns in many diagnostic diagrams, while P-Cygni profiles are highly variable on time-scales of minutes. The comparison between the three outbursts reveals that the spectra obtained during June and December 2015 share many similarities, while those from 1989 exhibit narrower emission lines and lower wind terminal velocities. The diagnostic diagrams presented in this work have been produced using standard measurement techniques and thus may be applied to other active low-mass X-ray binaries.Comment: Accepted for publication in MNRAS. 23 pages paper, plus a 9 pages appendix with extra tables and figures. 18 figures are included in the paper and 8 in the appendi

    Familial hypercholesterolemia: Molecular characterization of possible cases from the Azores Islands (Portugal)

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    Familial hypercholesterolemia (FH) is an autosomal dominant disorder of the cholesterol metabolism, which constitutes a risk factor for coronary arterial disease (CAD). In the Azores Islands (Portugal), where mortality from CAD doubles its rate comparatively to the rest of the country and where a high frequency of dyslipidemia has been reported, the prevalence and distribution of FH remain unknown. The molecular characterization of a group of 33 possible cases of FH of Azorean background was undertaken in this study. A DNA array was initially used to search mutations in the LDLR, APOB and PCSK9 loci in 10 unrelated possible cases of FH. No mutations were detected in the array; after sequencing the full LDLR gene, 18 variants were identified, corresponding to two missense (c.806G > A; c.1171G > A) and sixteen synonymous alterations. Six of the synonymous variants which are consistently described in the literature as associated with altered cholesterol levels were used to build haplotypes. The most frequent haplotype corresponded to TTCGCC (45%), a "risk" haplotype, formed exclusively by alleles that were reported to increase cholesterol levels. Some of the variants detected in the full sequencing of the LDLR gene fell within the ligand-binding domain of this gene, defined by exons 2 to 6. To add information as to the role of such variants, these exons were sequenced in the remaining 23 possible FH cases. Two missense alterations (c.185C > T; c.806G > A) were found in this subset of possible FH cases. The missense alteration c.185C > T, identified in one individual, is novel for the Portuguese population. In silico analysis was not conclusive for this alteration, whose role will have to be further investigated. This study represents the first approach to the establishment of the mutational profile of FH in the Azores Islands.This work was supported by the project entitled “High prevalence pathologies in the Azores: genetic and biochemical markers” with reference (M2.1.2/I/026/2008) funded by SRCTE. M. R. receives a PhD fellowship (M3.1.2/F/006/2011) from Fundo Regional para a Ciência. T.C. receives a post-doctoral fellowships from Fundação para a Ciência e a Tecnologia (SFRH/BPD/38659/ 2007) and N. K. (M3.1.7/F/002/2008) and A. R. (M3.1.7/F/031/2011) both receives post-doctoral fellowships from Fundo Regional para a Ciência
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