Evaluation of easy-removing antioxidant films of chitosan with Melaleuca alternifolia essential oil

Chitosan - tea tree essential oil (TTEO) films were obtained as a new biodegradable material. Malic acid or lactic acid solvents were evaluated to obtain easy-removing films. The microstructure by SEM and FT-IR, the thermal properties by TGA/DSC, the mechanical properties, the water vapor permeability, the antioxidant (DPPH• and ABTS•+) activity and the optical properties of the formulated films were evaluated. A complete dissolution of the film in water was obtained. The elongation to break was higher in the films with malic acid (145.88–317.33%), comparing with those with lactic acid (25.54–44.08%). Chitosan film obtained in malic acid with TTEO showed the highest antioxidant activity. The colour and transparency of the samples did not suffer significant variations by TTEO addition. Films showed good UV-barrier properties, with a slightly improvement by TTEO addition. The films obtained showed a great potential for food packaging applicationsThe authors appreciate the funding support of PROM International Scholarship Exchange for PhD Students and Academic Staff (NAWA, Poland), co-financed from the European Social Fund under the Operational Programme Knowledge Education Development, non-competitive project entitled International Scholarship Exchange for PhD Students and Academic Staff, under the contract POWR.03.03.00-00-PN13/18, with the fellowship granted to Patricia Cazón DíazS

Revisiting the implications of Liouville's theorem to the anisotropy of cosmic rays

We present a solution to Liouville's equation for an ensemble of charged particles propagating in magnetic fields. The solution is presented using an expansion in spherical harmonics of the phase space density, allowing a direct interpretation of the distribution of arrival directions of cosmic rays. The results are found for chosen conditions of variability and source distributions. We show there are two conditions for an initially isotropic flux of particles to remain isotropic while traveling through a magnetic field: isotropy and homogeneity of the sources. The formalism is used to analyze the data measured by the Pierre Auger Observatory, contributing to the understanding of the dependence of the dipole amplitude with energy and predicting the energy in which the quadrupole signal should be measured

Cosmic-Ray Anisotropies in Right Ascension Measured by the Pierre Auger Observatory

We present measurements of the large-scale cosmic-ray (CR) anisotropies in R.A., using data collected by the surface detector array of the Pierre Auger Observatory over more than 14 yr. We determine the equatorial dipole component, through a Fourier analysis in R.A. that includes weights for each event so as to account for the main detector-induced systematic effects. For the energies at which the trigger efficiency of the array is small, the east-west method is employed. Besides using the data from the array with detectors separated by 1500 m, we also include data from the smaller but denser subarray of detectors with 750 m separation, which allows us to extend the analysis down to ∼0.03 EeV. The most significant equatorial dipole amplitude obtained is that in the cumulative bin above 8 EeV, %, which is inconsistent with isotropy at the 6σ level. In the bins below 8 EeV, we obtain 99% CL upper bounds on d ⊥ at the level of 1%-3%. At energies below 1 EeV, even though the amplitudes are not significant, the phases determined in most of the bins are not far from the R.A. of the Galactic center, at GC =-94°, suggesting a predominantly Galactic origin for anisotropies at these energies. The reconstructed dipole phases in the energy bins above 4 EeV point instead to R.A. that are almost opposite to the Galactic center one, indicative of an extragalactic CR origin

EUSO-SPB1 mission and science

The Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of ⪆ 3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search

Wheat Blast: A Disease Spreading by Intercontinental Jumps and Its Management Strategies

Wheat blast (WB) caused by Magnaporthe oryzae pathotype Triticum (MoT) is an important fungal disease in tropical and subtropical wheat production regions. The disease was initially identified in Brazil in 1985, and it subsequently spread to some major wheat-producing areas of the country as well as several South American countries such as Bolivia, Paraguay, and Argentina. In recent years, WB has been introduced to Bangladesh and Zambia via international wheat trade, threatening wheat production in South Asia and Southern Africa with the possible further spreading in these two continents. Resistance source is mostly limited to 2NS carriers, which are being eroded by newly emerged MoT isolates, demonstrating an urgent need for identification and utilization of non-2NS resistance sources. Fungicides are also being heavily relied on to manage WB that resulted in increasing fungal resistance, which should be addressed by utilization of new fungicides or rotating different fungicides. Additionally, quarantine measures, cultural practices, non-fungicidal chemical treatment, disease forecasting, biocontrol etc., are also effective components of integrated WB management, which could be used in combination with varietal resistance and fungicides to obtain reasonable management of this disease

Interactions between Cosmic Rays and the Atmosphere: Modeling and Practical Applications

Cosmic rays arriving at Earth's atmosphere, where they produce up to billions of secondary particles, may provide a very valuable information about the changes in the atmosphere. We consider cosmic rays both as an object of research and as a research tool. The first part of the research is devoted to the problem of the influence of changes in the atmosphere on the intensity of secondary components of cosmic rays at the surface. Some of the greatest experiments of cosmic rays observed a strong correlation of the stratosphere's temperature with the arrival of high energy cosmic muons. We analyse the possibility of reproducing those measurements using a small detector of high resolution, called TRAGALDABAS, installed at the Faculty of Physics of the Univ. of Santiago de Compostela, in Spain. In order to achive our goals, we select low energy events and look for correlations between muon rates and the temperature profiles provided by reanalysis datasets. Our aim focuses also on evaluating the vertical temperature profiles for different atmospheric situations, developing a Monte Carlo code to simulate cosmic-ray cascades in the atmosphere. Eventually, we evaluate the inverse problem of retrieving the temperature profiles using cosmic-ray data taken at the surface. This gives rise to the future possibility of using such devices to improve very significantly the mid and long term weather forecast. In the second part of the research, we study the influence of cosmic rays on the atmosphere. In particular, we investigate the effect of cosmic-ray induced ionization in the atmosphere, which is modulated by the solar activity, in the growth of aerosols, small atmospheric particles precursors of cloud condensation nuclei. To this end, we use a global 3-D model of atmospheric chemistry to perform several simulations of different atmospheric situations durin

Multiscale Soil Carbon Distribution in Two Sub-Arctic Landscapes

In recent years, concern has grown over the consequences of global warming. The arctic region is thought to be particularly vulnerable to increasing temperatures, and warming is occurring here substantially more rapidly than at lower latitudes. Consequently, assessments of the state of the Arctic are a focus of international efforts. For the terrestrial Arctic, large datasets are generated by remote sensing of above-ground variables, with an emphasis on vegetation properties, and, by association, carbon fluxes. However, the terrestrial component of the carbon (C) cycle remains poorly quantified and the below-ground distribution and stocks of soil C can not be quantified directly by remote sensing. Large areas of the Arctic are also difficult to access, limiting field surveys. The scientific community does know, however, that this region stores a massive proportion (although poorly quantified, soil C stocks for tundra soils vary from 96 to 192 Gt C) of the global reservoir of soil carbon, much of it in permafrost (900 Gt C), and these stocks may be very vulnerable to increased rates of decomposition due to rising temperatures. The consequences of this could be increasing source strength of the radiatively forcing gases carbon dioxide (CO2) and methane (CH4). The principal objective of this project is to provide a critical evaluation of methods used to link soil C stocks and fluxes at the usual scales spanned by the field surveys (centimetre to kilometre) and remote sensing surveys (kilometre to hundreds of kilometres). The soil C distribution of two sub-arctic sites in contrasting climatic, landscape/geomorphologic and vegetation settings has been described and analysed. The transition between birch forest and tundra heath in the Abisko (Swedish Lapland) field site, and the transition between mire and birch forest in the Kevo (Finnish Lapland) field site span several vegetation categories and landscape contexts. The natural variability of below-ground C stocks (excluding coarse roots > 2 mm diameter), at scales from the centimetre to the kilometre scale, is high: 0.01 to 18.8 kg C m-2 for the 0 - 4 cm depth in a 2.5 km2 area of Abisko. The depths of the soil profiles and the soil C stocks are not directly linked to either vegetation categories or Leaf Area Index (LAI), thus vegetation properties are not a straightforward proxy for soil C distribution. When mapping soil or vegetation categories over large areas, it is usually necessary to aggregate several vegetation or soil categories to simplify the output (both for mapping and for modelling). Using this approach, an average value of 2.3 kg C m-2 was derived both for soils beneath treeless areas and forest understorey. This aggregated value is potentially misleading, however, because there is significant skew resulting from the inclusion of exposed ridges (with very low soil C stocks) in the ‘treeless’ category. Furthermore, if birch trees colonise tundra heath and other ‘open’ plant communities in the coming decades, there will likely be substantial shifts in soil C stocks. This will be both due to direct climate effects on decomposition, but also due to changes in above- and below-ground C inputs (both in quantity and quality) and possibly changes in so-called root ‘priming’ effects on the decomposition of existing organic matter. A model of soil respiration using parameters from field surveys shows that soils of the birch forest are more sensitive to increases in mean annual temperature than soils under tundra heath. The heterogeneity of soil properties, moisture and temperature regimes and vegetation cover in ecotone areas means that responses to climate change will differ across these landscapes. Any exercise in upscaling results from field surveys has to indicate the heterogeneity of vegetation and soil categories to guide soil sampling and modelling of C cycle processes in the Arctic

Evaluación biológica pesquera de elasmobranquios capturados por la pesca artesanal en el Golfo de Chiriquí.

Los elasmobranquios constituyen parte de la denominada "captura incidental" en las capturas de especies objetivo, tanto en la pesca artesanal como en la pesca industrial. En este sentido se analizaron las capturas de tiburones y rayas como consecuencia de la pesca artesanal en el Golfo de Chiriquí. El estudio se realizó entre marzo 2009 y agosto 2010 se incluyó 53 faenas, con cuatro artes diferentes de pesca (palangre de fondo, palangre superficial, línea vertical y redes agalleras) dirigidos a la captura de pargo, cherna, dorado, corvinas y otros grupos conocidos como revoltura; adicionalmente se realizaron 77 observaciones de descarga procedentes de la pesca con redes agalleras. Durante las observaciones a bordo de embarcaciones se registró información operacional y biológica (identificación de especies, cantidad, peso, sexo, condición reproductiva y longitud total). En total se capturaron 754 tiburones y 22 rayas pertenecientes, a 14 especies de tiburones y 8 de rayas. De los tiburones capturados, Sphyrna lewini representó el 59 % del total, Carcharhinus porosus, 12.1 %, Mustelus lunulatus 9.4 %, Carcharhinus limbatus 7.4 % y Nasolamia velox (6.6 %). El resto de las especies (S tiburo S media, S corona, Alopias pelagicus, M dorsalis, Galeocerdo curvier, Rhizoprionodon longurio Ginglymostoma cirratum y Triaenodon obesus) no superaron el 6 % de la captura total. De las rayas las más frecuentes fueron Rhinobatos leucorhynchus y Dasyatis longa y ocasionalmente Aetobatus narinari Urotrigon rogesi, Zapteryx exasperata, Rhinobatos glaucostigma y Raja velezi. Con relación a la reproducción solo 41 tiburones de los 754 capturados fueron clasificados como adultos 16 correspondieron a M lunulatus y 11 a C porosus. Relevante es el caso de S lewini donde de los 448 ejemplares capturados solamente uno resultó adulto, un macho de 216.6 cm de LT. La captura por unidad de esfuerzo con el palangre de fondo fue de 0.5 md/1000 anz. (70 015 anzuelos calados) con palangre superficial, 0.08 md/1000 anz. (13 533 anzuelos calados) mientras que con trasmallo se capturaron 1.62 ind/lance (250 lances). La talla promedio mostró diferencias significativas según arte de pesca. El palangre de superficie capturó ejemplares de mayor talla (X = 115.1 ± 31.9 cm) seguido del palangre de fondo y la línea vertical sin diferencias entre ellas (palangre de fondo X= 90.0 ± 22.01 cm, línea vertical X = 87 ± 19.54 cm) y los individuos de menor tamaño fueron capturados con redes agalleras malla de tres pulgadas (X = 55.9 ± 14.66 cm). En el caso de las rayas solo se capturaron con palangre de fondo 0.02 ind/1000 anz. y redes agalleras O.02 ind/lance. Los desembarques estuvieron dominados por juveniles del género Sphyrna y Cacharinus que se comercializan por su carne y aletas

Evaluación biológica-pesquera de elasmobranquios capturados por la pesca artesanal en el Golfo de Chiriquí

Los Elasmobranquios constituyen parte de la denominada "captura incidental" en las capturas de especies objetivo, tanto en la pesca artesanal como en la pesca industrial. En este sentido se analizaron las capturas de tiburones y rayas como consecuencia de la pesca artesanal en el Golfo de Chiriquí. El estudio se realizó entre marzo 2009 y agosto 2010 se incluyó 53 faenas, con cuatro artes diferentes de pesca (palagre de fondo, palagre superficial, línea vertical y redes agalleras) dirigidos a la captura de pargo, cherna, dorado, corvinas y otros grupos conocidos como revoltura; adicionalmente se realizaron 77 observaciones de descarga procedentes de la pesca con redes agalleras. Durante las observaciones a bordo de embarcaciones se registró información operacional y biológica (identificación de especies, cantidad, peso, sexo, condición reproductiva y longitud total). En total se capturaron 754 tiburones y 22 rayas, pertenecientes a 14 especies de tiburones y 8 de 4 rayas. De los tiburones capturados, Sphyrna lewini representó el 59%, Carcharhinus porosus, 12.1%, Mustelus lunulatus 9.4%, Carcharhinus limbatus 7.4% y Nasolamia velox (6.6%). El resto de las especies (S. tiburo S. media, S. corona, Alopias pelagicus, M. dorsalis, Galeocerdo curvier, Rhizoprionodon longurio, Ginglymostoma cirratum y Triaenodon obesus), no superaron el 6% de la captura total. De las rayas las más frecuentes fueron Rhinobatos leucorhynchus y Dasyatis longa y ocasionalmente, Aetobatus narinari, Urotrigon rogesi, Zapteryx exasperata, Rhinobatos glaucostigma y Raja velezi. Con relación a la reproducción, solo 41 tiburones de los 754 capturados fueron clasificados como adultos, 16 correspondieron a M. lunulatus y 11 a C. prosus. Relevante es el caso de S. lewini, donde de los 448 ejemplares capturados solamente uno resultó adulto, un macho de 216.6 cm de LT. La captura por unidad de esfuerzo con el palangre de fondo fue de 0.5 ind/1000 anz. (70 015 anzuelos calados), con palangre superficial, 0.08 ind/1000 anz (13 533 anzuelos calados), mientras que con trasmallo, se capturaron 1.62 ind/lance (250 lances). La talla promedio mostró diferencias significativas según arte de pesca. El palangre de superficie capturó ejemplares de mayor talla (X= 115.1Î 31.9 cm), seguido del palangre de fondo y la línea vertical, sin diferencias entre ellas (palangre de fondo X= 90.0 Î 22.01 cm, línea vertical X= 87 Î19.54 cm) y los individuos de menor tamaño fueron capturados con redes agalleras, malla de tres pulgadas (X= 55.9 Î14.66 cm). En el caso de las rayas, solo se capturaron con palangre de fondo, 0.02 ind/1000 anz. Y redes agalleras, 0.02 ind/lance. Los desembarques estuvieron dominados por juveniles del género Sphyrna y Cacharinus que se comercializan por su carne y aletas