Oxygen Uptake Kinetics Is Slower in Swimming Than Arm Cranking and Cycling during Heavy Intensity.

Oxygen uptake ([Formula: see text]) kinetics has been reported to be influenced by the activity mode. However, only few studies have compared [Formula: see text]O2 kinetics between activities in the same subjects in which they were equally trained. Therefore, this study compared the [Formula: see text]O2 kinetics response to swimming, arm cranking, and cycling within the same group of subjects within the heavy exercise intensity domain. Ten trained male triathletes (age 23.2 ± 4.5 years; height 180.8 ± 8.3 cm; weight 72.3 ± 6.6 kg) completed an incremental test to exhaustion and a 6-min heavy constant-load test in the three exercise modes in random order. Gas exchange was measured by a breath-by-breath analyzer and the on-transient [Formula: see text]O2 kinetics was modeled using bi-exponential functions. [Formula: see text]O2peak was higher in cycling (65.6 ± 4.0 ml·kg(-1)·min(-1)) than in arm cranking or swimming (48.7 ± 8.0 and 53.0 ± 6.7 ml·kg(-1)·min(-1); P < 0.01), but the [Formula: see text]O2 kinetics were slower in swimming (τ1 = 31.7 ± 6.2 s) than in arm cranking (19.3 ± 4.2 s; P = 0.001) and cycling (12.4 ± 3.7 s; P = 0.001). The amplitude of the primary component was lower in both arm cranking and swimming (21.9 ± 4.7 and 28.4 ± 5.1 ml·kg(-1)·min(-1)) compared with cycling (39.4 ± 4.1 ml·kg(-1)·min(-1); P = 0.001). Although the gain of the primary component was higher in arm cranking compared with cycling (15.3 ± 4.2 and 10.7 ± 1.3 ml·min(-1)·W(-1); P = 0.02), the slow component amplitude, in both absolute and relative terms, did not differ between exercise modes. The slower [Formula: see text]O2 kinetics during heavy-intensity swimming is exercise-mode dependent. Besides differences in muscle mass and greater type II muscle fibers recruitment, the horizontal position adopted and the involvement of trunk and lower-body stabilizing muscles could be additional mechanisms that explain the differences between exercise modalities

Covalent organic frameworks as catalyst support: A case study of thermal, hydrothermal, and mechanical pressure stability of β-ketoenamine-linked TpBD-Me2

Covalent organic frameworks (COFs) are crystalline, ordered networks, that, due to their high surface areas and the opportunity for periodic placement of catalytically active sites, are interesting materials for catalysis. Despite the great interest in the use of COFs for this application, there is currently a lack of fundamental understanding on how catalytically relevant conditions affect the integrity of the materials. To gain insight into the stability of COFs as catalyst supports, we herein subjected a β-ketoenamine-linked COF to thermal treatment at high temperatures, to autogenous pressure in water at different temperatures, and to mechanical pressure during pelletizing, after which the materials were thoroughly characterized to gain insight into the structural changes occurring during these catalytically relevant treatments. The COF was largely stable under all hydrothermal conditions studied, highlighting the applicability of β-ketoenamine-linked COFs under aqueous and vapor conditions. On the other hand, thermal and pressure treatments led to a rapid decline in the surface area already at the lowest temperatures and pressures studied. Theoretical calculations indicated this loss to stem from interlayer rearrangement or buckling of the COF layers induced by the applied conditions. This study demonstrates the suitability of β-ketoenamine-linked COFs for use under hydrothermal conditions, and sheds light on the degradation pathways under thermal and pressure treatments, opening the path to the design of COFs with increased stability under such conditions.Fundação para a Ciência e a Tecnologia | Ref. UTA-EXPL/NPN/0055/2019Fundação para a Ciência e a Tecnologia | Ref. PTDC/QUI-OUT/2095/2021Fundação para a Ciência e a Tecnologia | Ref. PTDC/EQU-EQU/1707/2020Agencia Estatal de Investigación | Ref. RYC2020-030414-IUniversidade de Vigo/CISU

Recopilación de métodos analíticos para la caracterización y determinación del quitosano y las principales aplicaciones del polímero en los envases activos alimentarios

Antimicrobial films for food packaging applications have received increasing attention from the industry in recent years. Due to their exceptional properties, such as non-toxicity, biodegradability, antimicrobial characteristics, and biocompatibility, chitosan has proven useful for the development of active materials. This review aims to provide anoverview of the main techniques used for the characterization of chitin and chitosan, including Fourier transforminfrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, UV spectrophotometry, viscosimetry, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), titrations, scanning electron microscopy (SEM) and size exclusion chromatography (SEC) among others. In addition, the main applications of the polymer in food packaging are also reportedEn los últimos años los films antimicrobianos han recibido una gran atención por parte de la industria para su aplicación en el envasado alimentario. Debido a sus excepcionales propiedades, no-tóxico, biodegradable, características antimicrobianas y biocompatible, el quitosano ha demostrado ser útil para el desarrollo de materiales activos. Este artículo de revisión tiene por objeto proporcionar una visión general de las principales técnicas usadas para la caracterización de quitina y quitosano incluidas la espectroscopia infrarroja (FTIR), la espectroscopia RMN de 1H y 13C, la espectrofotometría UV, viscosimetría, análisis elemental, difracción de rayos-X (XRD), análisis termogravimétrico (TGA), titulaciones, microscopía electrónica de barrido (SEM) y cromatografía de exclusión por tamaños (SEC)entre otras. Además, se describen las principales aplicaciones del polímero en el envasado de los alimentosThis work was funded under the Project no. 95935 from FONCICYT C002-2008-1/ALA 127 249S

Cyprus as an ancient hub for house mice and humans

© 2018 The Authors. Journal of Biogeography Published by John Wiley & Sons Ltd Aim: The distribution of the western house mouse (Mus musculus domesticus) around the world has been strongly influenced by the movement of humans. The close association between the house mouse and human phylogeography has been primarily studied in the peripheral distribution of the species. Here, we inferred the complex colonization history of Cyprus, situated close to the centre of the house mouse distribution and one of the first European islands to be colonized by the species. We investigated the resulting complexity of house mouse population genetics as well as considering the value of the house mouse as a bioproxy for studying modern human movement. Location: The study was carried out on Cyprus. Methods: The analysis was performed using 221 new mitochondrial D-loop sequences and assessed the fine-scale population genetic structure using 18 autosomal microsatellite loci from 191 modern house mice specimens. Results: We found a high genetic variability in the island that is illustrated by the presence of individuals from 9 of the 11 previously identified house mouse haplogroups for the D-loop, reflecting the hub-like nature of the island to mice. Two main waves of mouse introductions were tentatively identified based on coalescent and mismatch analysis. The first is apparently related to the Bronze Age expansion and the second one to more recent human movements. Cyprus represents an island with high complexity due to different introductions related to human transport and activity. Main conclusions: The dispersal of mice along with humans has left a complex footprint on the island with two main waves of introductions suggested. The phylogeography of the house mouse on Cyprus is in concordance with the complex human colonization history of the island and validates the use of the house mouse as a proxy to study human migration

The poetics of indigenous radio in Colombia

In 2002, 14 indigenous radio stations began operating in Colombia reaching 78.6 percent of the national indigenous population. Colombian indigenous radio stations are shaped by intense deliberations among each indigenous people about the poetics of information and communication technologies, understood as the exploration of the specific sets of social, cultural and political relations in which each radio station would exist if brought into each indigenous territory. Colombian indigenous peoples' appropriation of information and communication technologies is framed by new legislative frameworks made possible by the Colombian constitutional reform of 1991, by indigenous peoples' critique of Colombian mainstream media and, more significantly, by discussions among indigenous peoples about the adoption of radio — what we call a poetics of radio.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Morphometrics and genetics highlight the complex history of Eastern Mediterranean spiny mice

© 2020 The Linnean Society of London, Biological Journal of the Linnean Society. Spiny mice of the Acomys cahirinus group display a complex geographical structure in the Eastern Mediterranean area, as shown by previous genetic and chromosomal studies. To better elucidate the evolutionary relationships between insular populations from Crete and Cyprus and continental populations from North Africa and Cilicia in Turkey, genetic and morphometric variations were investigated, based on mitochondrial D-loop sequences, and the size and shape of the first upper molar. The Cypriot and the Cilician populations show idiosyncratic divergence in molar size and shape, while Cretan populations present a geographical structure with at least three differentiated subpopulations, as shown by congruent distributions of haplogroups, Robertsonian fusions and morphometric variation. A complex history of multiple introductions is probably responsible for this structure, and insular isolation coupled with habitat shift should have further promoted a pronounced and rapid morphological evolution in molar size and shape on Crete and Cyprus

Asymptotic behaviour of the gluon propagator from lattice QCD

We study the flavorless gluon propagator in the Landau gauge from high statistics lattice calculations. Hypercubic artifacts are efficiently eliminated by taking the $\sum p_\mu^4 \to 0$ limit. The propagator is fitted to the three-loops perturbative formula in an energy window ranging form $\sim$ 2.5 GeV up to $\sim$ 5.5 GeV. $\alpha_s$ is extracted from the best fit in a continuous set of renormalisation schemes. The fits are very good, with a $\chi^2$ per d.o.f smaller than 1. We propose a more stringent test of asymptotic scaling based on scheme independence of the resulting $\Lambda_{\bar MS}$. This method shows that asymptotic scaling at three loops is not reached by the gluon propagator although we use rather large energies. We are only able to obtain an effective flavorless three-loops estimate $\Lambda_{\bar MS}^{(3)}= 353 \pm 2 ^{+25}_{-10}$ MeV. We argue that the real asymptotic value for $\Lambda_{\bar MS}$ should plausibly be smaller.Comment: 16 pages, 9 figures, revTe

Sedimentary cycles in a Mesoproterozoic aeolian erg-margin succession: Mangabeira Formation, Espinhaço Supergroup, Brazil

Aeolian systems were abundant and widespread in the early Proterozoic, post-2.2 Ga. However, the majority of aeolian successions of such great age are intensely deformed and are preserved only in a fragmentary state meaning that, hitherto, few attempts have been made to apply a sequence stratigraphic approach to determine mechanisms of aeolian construction, accumulation and preservation in such systems. The Mangabeira Formation is a well preserved Mesoproterozoic erg successions covering part of the São Francisco Craton, northeastern Brazil. The lower unit of the Mangabeira Formation (~ 500 m thick) comprises aeolian deposits of dune, interdune, and sand-sheet origin, as well as some of waterlain origin. These deposits are organized into vertically stacked depositional cycles, each 6 to 20 m thick, and characterized by aeolian sandsheet and waterlain deposits succeeded by aeolian dune and interdune deposits indicative of a drying-upward trend. Aeolian cross-strata exhibit a mean dip direction to the north. Each of these cycles likely arose in response to climatic oscillation from relatively humid to arid conditions, possibly related to orbital forcing. The lower unit of the Mangabeira Formation comprises up to 14 erg sequences. The accumulation and preservation of each was determined by the relative rate of water-table rise and the availability of sand for aeolian transport, both of which changed through time, resulting in the preservation of a succession of repeated drying-upward cycles

Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius $A$. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic