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Assessment of aerosol optical depth using MAIAC and AERONET data during the 2020 wildfire season in southeastern South America

2026-01-01T00:00:00Z

Título: Assessment of aerosol optical depth using MAIAC and AERONET data during the 2020 wildfire season in southeastern South America Autor: Valle Seijo, María Fernanda; Otero, Lidia Ana; Agesta, Alejandro; Frins, Erna; Piacentini, Rubén Darío Resumen: Wildfires are major contributors to air pollution, with significant impacts on regional air quality and public health. The objective of this study is to assess aerosol optical depth (AOD) during the intense 2020 wildfire season in southeastern South America. AOD data were retrieved from the MAIAC/MODIS algorithm and fire data from VIIRS/SUOMI-NPP satellite. The satellite AOD was correlated with AERONET measurements over Buenos Aires and Montevideo to evaluate satellite performance during fire periods, with higher correlations expected under smoke dominated conditions. Results for the whole area reveal significantly higher AOD values in 2020, with a median of approximately 0.118. Seasonal analysis highlights notable peaks in fire pixel counts during austral spring (median AOD = 0.154) and winter 2020 (median AOD = 0.114). AERONET observations indicated robust correlations with MAIAC AOD during 2020 (R = 0.75). Moderately strong correlations are observed during winter and spring due to elevated aerosol loads from biomass burning. Specifically, Buenos Aires exhibited changes in the AOD-Ångstrom ¨ Exponent relationship, indicating fine-mode aerosol dominance, while Montevideo displayed less pronounced variability but consistent seasonal patterns. These findings show the impact of biomass burning events on air quality, and the utility of integrating satellite and ground-based data for aerosol analysis.

Supplementation with eicosapentaenoic and docosahexaenoic acids during late gestation alters fatty acid profiles in ewe colostrum, milk, and plasma, and lamb plasma

2025-01-01T00:00:00Z

Título: Supplementation with eicosapentaenoic and docosahexaenoic acids during late gestation alters fatty acid profiles in ewe colostrum, milk, and plasma, and lamb plasma Autor: Carranza Martin, Ana Cristina; Nickles, Kirsten; Sherlock, Danielle Nicole; Relling, Alejandro E. Resumen: Our aim was to evaluate the effects of increasing dietary levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) during the final third of gestation on plasma and milk fatty acid (FA) profiles of ewes and their offspring. Additionally, correlation between maternal and offspring plasma, colostrum, and milk FA profiles were examined. Seventy-two pregnant ewes (92.2 ± 2.94 kg body weight at d 100 of gestation) were blocked by body condition score and randomly assigned to one of three diets containing 0, 1, or 2% of a Ca salt of FA enriched with EPA and DHA during the last 50 d of gestation. Animals were housed in 8 pens per treatment (3 ewes per pen) during the supplementation period. At lambing, all ewes were penned together and offered a diet without FA supplementation. For FA profile, blood samples were collected from ewes at d -20 prepartum, at lambing, and d 15 postpartum. Lamb plasma samples were obtained at birth (0.5 to 8 h post-suckling). Colostrum (0.5 to 8 h postpartum) and milk (d 15 postpartum) were also collected. Data were analyzed using a randomized complete block design. The model included the fixed effects of the treatment for lamb plasma FA profile; and the fixed effects of treatment, time, and their interaction for ewe plasma and colostrum and milk FAprofile. Supplementation with EPA and DHA increased (diet by time interaction; P ≤ 0.06) the polyunsaturated FA (PUFA; C20:40, C20:5, and all omega 3) in ewe plasma until lambing but was similar between treatments 15 d post lambing. Colostrum from supplemented ewes showed greater PUFA (C22:5 and C22:6) concentrations and the difference decreased in the milk (diet by time interaction; P < 0.01), although the colostrum PUFA increase was not correlated with most individual plasma PUFA (C18:2, C20:3n6 and n3, C20:4, C20:5, C22:5, and C22:6), except for C18:3, which showed a positive association (P = 0.03). Furthermore, colostrum PUFA concentrations were positively correlated with the FA composition of lamb plasma post-suckling (P < 0.02). The PUFA concentrations were also increased in lamb plasma at lambing (P < 0.01), suggesting potential effects on neonatal lipid metabolism. These findings demonstrate that dietary supplementation with EPA and DHA, initiated 50 days before lambing and terminated at parturition, can alter the FA composition of maternal plasma, colostrum, and milk, and also influence the plasma FA profile of the offspring.

Fermi Sea Topology and Boundary Geometry for Free Particles in One- and Two-Dimensional Lattices

2026-01-01T00:00:00Z

Título: Fermi Sea Topology and Boundary Geometry for Free Particles in One- and Two-Dimensional Lattices Autor: Zemba, Guillermo Raúl Resumen: Free gases of spinless fermions moving on a lattice-symmetric geometric background are considered. Their topological properties at zero temperature can be used to classify their Fermi seas and associated boundaries. The flat orbifolds ℝ𝑑/Γ , where Γ is the crystallographic group of symmetry in d-dimensional momentum space, are used to accomplish this task. Two topological classes exist for 𝑑=1 : an interval, which is identified as a conductor, and a circumference, which corresponds to an insulator. The number of topological classes increases to 17 for 𝑑=2 : 8 have the topology of a disk, that are generally recognized as conductors, and 4 correspond to a two-sphere, matching insulators. Both sets eventually contain a finite number of conical singularities and reflection corners at the boundaries. The remaining cases in the listing relate to conductors (annulus, Möbius strip) and insulators (two-torus, real projective plane, Klein bottle). Examples that fall under this list are given, along with physical interpretations of the singularities. It is anticipated that the findings of this classification will be robust under perturbative interactions due to its topological character.

Spatial Variation in Turf Surface Properties of Polo Pitches: A Case Study of Different Handicaps of Argentina

2026-01-01T00:00:00Z

Título: Spatial Variation in Turf Surface Properties of Polo Pitches: A Case Study of Different Handicaps of Argentina Autor: Blanco, María Alejandra; Peterson, Michael L.; Cipriotti, Pablo Ariel; Apecechea, Fernando Resumen: Polo is a high-speed equestrian sport that imposes mechanical demands on horses and turf, yet limited research has examined the functional behavior of polo playing surfaces. This study characterizes the spatial variability of mechanical surface properties across turf polo pitches representing high-, medium-, and low-handicap categories. Three fields were assessed using lightweight field-based instruments, including the Impact Test Device (ITD), Rotational Peak Shear (RPS) tester, Going Stick© for penetration (GSP) and shear (GSS), and a TDR probe for volumetric moisture content (VMC%). A total of 210–223 grid-based sampling points per pitch were analyzed to evaluate mechanical responses under vertical and horizontal loading conditions. Significant differences among pitches were observed, with ITD and VMC emerging as the indicators of surface behaviour. Spatial analysis revealed heterogeneous within-pitch patterns, expressed as directional gradients and localized variability. Linear discriminant analysis demonstrated that the combined measurements could differentiate pitches associated with different handicap levels with high classification accuracy (0.88). Although the applied instruments do not replicate full equine biomechanical loading, they proved effective in detecting spatial variability in surface uniformity, a functional property relevant to performance and equine welfare. These findings support integration of spatially explicit surface assessments into routine turf management practices.