Austral University of Chile

Field trials were conducted to define several parameters associated with adding LEDs to monitoring traps for codling moth (CM), Cydia pomonella (L.), using both a sex pheromone lure (PH1X) and a non-pheromone lure (CM4K). Traps with LEDs emitting at a peak of 395 nm with 1000-2000 mW/m2 were the most effective. Lights with greater intensities caught similar numbers of CMs and significantly more non-targets. Adding the UV-A lights did not increase moth catches early in the season with either the PH1X or CM4K lures. However, UV-A LEDs, when used with these two lures, significantly increased total moth catches 7- and 3-fold in July and August, respectively. The addition of the UV-A LEDs allowed CM4K-baited traps to perform significantly better in previously limiting situations, such as in weedy orchards, and in pear relative to apple. Distance from the light source is a key factor affecting light energy. Irradiance dropped >90% at 15 cm, which is the distance from the lure to the entrance of a standard delta trap. A smaller trap (7.5 cm radius) had a 4-fold greater irradiance at its entrance and caught greater numbers of non-targets but not CMs than delta traps without LEDs.

Propolis is a chemically complex natural product with recognized antioxidant potential, but its compositional heterogeneity and poor aqueous solubility complicate formulation and interpretation of in vitro release behavior. In this study, a nanostructured lipid carrier (NLC) based on Gelucire® 44/14 was developed as a physicochemical platform to modulate the accessibility of a selected Chilean ethanolic propolis extract. Propolis extracts from different origins were first screened using complementary antioxidant assays (DPPH, ABTS, ORAC, FRAP), leading to the selection of the Peñaflor extract, which exhibited the highest phenolic content (~41 mg GAE/g) and antioxidant capacity. The selected extract was incorporated into NLCs with encapsulation efficiencies above 90%, a narrow size distribution (~200 nm), and high stability over 90 days. Under simple aqueous conditions, propolis release remained limited (<15% over 6 h), consistent with diffusion- and partition-controlled transport. In simulated gastrointestinal media containing bile components, pronounced pH- and composition-dependent effects were observed. While fed-state intestinal conditions induced extensive morphological remodeling without increasing the analytically accessible fraction (<3% at 4 h), fasted-state intestinal media promoted a higher accessible fraction (~14% within 1 h) without complete carrier disruption, as confirmed by transmission electron microscopy. Preliminary cytocompatibility studies in HepG2 cells showed acceptable viability at 10-40 µg/mL and concentration-dependent effects at higher doses. Overall, this work demonstrates that bile components modulate propolis accessibility through dynamic partitioning and colloidal reorganization rather than simple carrier breakdown, providing a physicochemical framework for future digestion and absorption studies.

The wildfire regime in South-Central Chile (SCC, 30º to 44ºS) has changed in recent decades due to changes in land use, climate conditions, and characteristics of weather extreme events. While during 1976-2016, the mean annual burned area was ~54,000 ha, during the last decade a sequence of seasons multiplied that value, in particular 2016-2017 with 570,000 ha and 2022-2023 with 450,000 ha. To the north of this region, the fire regime is fuel-limited (e.g. amount and connectivity of biomass), while to the south, it is primarily climate-limited (i.e. plenty of wet fuels). In contrast to all other Mediterranean regions worldwide, SCC has a very low rate of natural ignitions (520 ha, N~800) within 7 SCC sub-regions, previously delimited according to climate, topography, and land use. Using historical wildfire records (including start date, duration, and burned area) from the National Forestry Corporation (CONAF) spanning 1984-2025, we describe the mean local 15-days evolution of weather conditions centered on the start dates of wildfires. For this, we use daily ERA5 data, including maximum temperature, minimum specific humidity, mean sea-level pressure, and maximum surface wind intensity. Furthermore, within each subregion, a cluster analysis reveals distinct mean weather sequences and typical thresholds for these variables related to wildfires. While subtle weather variability is detected in the northern part of SCC, for the southern part of SCC our analysis reveals the relevance of mid-latitud synoptic variability–in particular blocking patterns induced by migratory anticyclones–, as well as associated mesoscale phenomena, especially coastal lows and foehn wind systems. Moreover, prominent differences in wildfire characteristics are found between distinct extreme weather events, such as heat waves and single hot days.As a second task, we explore the intra-seasonal evolution leading to selected weather patterns associated with wildfires in SCC. We find groups of events that reveal different sequences of significant mid-latitude and tropical circulation anomalies up to 14 days before the wildfire start dates. For each group, we show that the corresponding weather-fire relationship is in fact mediated by a distinct trajectory of the Fire Weather Index (FWI). Finally, we suggest a scheme based on the Madden-Julian Oscillation (MJO) index and the Standardized Extra-Tropical Index (sETI) to monitor intra-seasonal atmospheric teleconnections favoring weather fire in SCC.

How land-use intensity (LUI) affects soil structure-dependent functions and organic matter (OM) quality in Patagonian wetland soils (Vegas) of southern Chile is an intriguing question. These wetland soils, which store large amounts OM and regulate water and nutrient fluxes, are increasingly exposed to intensification. While degradation of peatlands under drainage and conversion to agricultural activities is well documented, the long-term effects of contrasting LUI under intensification of livestock systems and peat extraction in southern Patagonia remain poorly understood. Research was conducted along a west–east climatic and aridity gradient in the Magallanes Region Chile. Four pairs of Vegas with contrasting LUI, low-and-high-intensity use of livestock and peat extraction sites were selected, spanning Histosols and Gleysols, including sedge meadows and Sphagnum peatlands. At each site, environmental conditions, vegetation inventory, and livestock management (stocking rate and density) were characterized. Soil structure-dependent functions were quantified from undisturbed cores collected at the surface horizon (5 cm) and the last horizon (~ 70 cm) before the appearance of glacial material or the water table. The water retention and shrinkage curves were measured, and from this, the bulk density (BD), air capacity (AC), plant available water (PAW), coefficient of linear extensibility (COLE), air permeability (Ka) were derived. The saturated hydraulic conductivity (ks), and anisotropy of air and water flows were quantified. The total and dissolved organic carbon and nitrogen (TC, TOC, IC, DOC, TN, TIN and TON), stable isotopes (¹³C, ¹⁵N), and ATR-FTIR spectroscopy. Most Vegas showed high OC (3,69-44%) with very high porosity (&gt;80%), high shrinkage capacity, and strong deformation due to soil drying (COLE&gt; 0.09), particularly in Histosols. and ks decrease with depth, especially in Sphagnum peatlands due to the OM decomposition and pore-size reduction. A soil structural shrinkage phase normally is presence, being often a residual and zero-shrinkage phases absent under low LIU. Anisotropy in fluid conduction was sporadic and more pronounced in the Gleysolic sites. OM quality varied strongly in the top and depth soils across sites. Sphagnum peatlands had the highest C:N ratios and high FTIR signatures of recalcitrant organic compounds, whereas sedge-dominated Vegas showed more similar spectral patterns. Depth profile declines in C:N and shifts in ¹³C and ¹⁵N abundances showing progressive OM decomposition and N enrichment. Unexpectedly, we found that high LUI did not deteriorate the structure-dependent functions. In several cases, more intensive but better managed systems displayed higher porosity, greater ks and Ka, and well-developed structural shrinkage phases. However, peat extraction in Sphagnum systems clearly damaged structural integrity. Results indicate that LUI effects are context dependent and that both low-intensity and over grazing for livestock production can be detrimental. A high LUI did not result in a marked deterioration of structure dependent soil functions, instead, it revealed a continuum of responses across the study sites. Recovery in structure-dependent soil functions were primarily associated with increased organic matter content, accompanied by a relative enhancement in organic matter quality. This implies that low land use intensity can be just as harmful without proper utilization and controlled use of natural resources.