Spatial isolation impacts pollinator visitation and reproductive success of a threatened self-incompatible Mediterranean tree

Pollination service is crucial to achieve successful plant sexual reproduction and long-term population persistence. This pollination service can be affected by plant conspecific density and also by intrinsic features of individuals related to their flowering phenology and floral display. However, studies examining intrinsic and extrinsic traits on pollinator visitation and reproductive success of Mediterranean trees with limited reproduction are still scarce. We analyzed the effects of plant isolation, flowering phenology, flower weight and tree size on flower visitation probability, flowering patch visitation probability, fruit set and crop size. To this end, we intensively monitored pollinator visitation and fruit production of 67 (in 2019) and 73 (in 2020) Pyrus bourgaeana Decne trees within a threatened Mediterranean population. Our results revealed that isolated individuals received more pollinators than those on conspecific aggregations, suggesting intraspecific competition for pollinators in dense flowering neighborhoods. However, fruit set was higher in trees close to flowering conspecifics despite having fewer visits from pollinators, suggesting pollen limitation but not pollinator limitation in spatially isolated trees. Interestingly, we found increased crop sizes in spatially isolated trees which could be related to reduced intraspecific competition for resources in low-density neighborhoods (water, nutrients) and/or to higher reproductive investment (i.e. higher flower production). Overall, our results indicated pollen but not pollinator limitation in spatially isolated trees. Under this scenario of sexual reproduction mediated by pollinators, our findings stress the relevance of individuals’ spatial distribution for self-incompatible trees exhibiting low individuals’ densitiesinfo:eu-repo/semantics/publishedVersio

Dispersive ππ→KKˉ\pi\pi\rightarrow K\bar K amplitude and giant CP violation in B to three light-meson decays at LHCb

The LHCb collaboration has recently reported the largest CP violation effect from a single amplitude, as well as other giant CP asymmetries in several $B$-meson decays into three charmless light mesons. It is also claimed that this is predominantly due to $\pi\pi\rightarrow K\bar K$ rescattering in the final state, particularly in the 1 to 1.5 GeV region. In these analyses the $\pi\pi\rightarrow K\bar K$ amplitude is by default estimated from the $\pi\pi$ elastic scattering amplitude and does not describe the existing $\pi\pi\rightarrow K\bar K$ scattering data. Here we show how the recent model-independent dispersive analysis of $\pi\pi\rightarrow K\bar K$ data can be easily implemented in the LHCb formalism. This leads to a more accurate description of the asymmetry, while being consistent with the measured scattering amplitude and confirming the prominent role of hadronic final state interactions, paving the way for more elaborated analyses.Comment: 9 pages, 6 figures. Minor corrections and discussions were added. Extended appendix with an additional improved model of the S-wave. Final version to appear in Phys.Rev.Let

Interspecific interactions among functionally diverse frugivores and their outcomes for plant reproduction: a new approach based on camera-trap data and tailored null models

Research ArticleThe study of plant-frugivore interactions is essential to understand the ecology and evolution of many plant communities. However, very little is known about how interactions among frugivores indirectly affect plant reproductive success. In this study, we examined direct interactions among vertebrate frugivores sharing the same fruit resources. Then, we inferred how the revealed direct interspecific interactions could lead to indirect (positive or negative) effects on reproductive success of fleshy fruited plants. To do so, we developed a new analytical approach that combines camera trap data (spatial location, visitor species, date and time, activity) and tailored null models that allowed us to infer spatial-temporal interactions (attraction, avoidance or indifference) between pairs of frugivore species. To illustrate our approach, we chose to study the system composed by the Mediterranean dwarf palm, Chamaerops humilis, the Iberian pear tree, Pyrus bourgaeana, and their shared functionally diverse assemblages of vertebrate frugivores in a Mediterranean area of SW Spain. We first assessed the extent to which different pairs of frugivore species tend to visit the same or different fruiting individual plants. Then, for pairs of species that used the same individual plants, we evaluated their spatial-temporal relationship. Our first step showed, for instance, that some prey frugivore species (e.g. lagomorphs) tend to avoid those C. humilis individuals that were most visited by their predators (e.g. red foxes). Also, the second step revealed temporal attraction between large wild and domestic frugivore ungulates (e.g. red deer, cows) and medium-sized frugivores (e.g. red foxes) suggesting that large mammals could facilitate the C. humilis and P. bourgaeana exploitation to other smaller frugivores by making fruits more easily accessible. Finally, our results allowed us to identify direct interaction pathways, that revealed how the mutualistic and antagonistic relations between animal associates derived into indirect effects on both plants seed dispersal success. For instance, we found that large-sized seed predators (e.g. ungulates) had a direct positive effect on the likelihood of visits by legitimate seed dispersers (e.g. red foxes) to both fleshy fruited plants. Then, seed predators showed an indirect positive effect on the plants’ reproductive Our new analytical approach provides a widely applicable framework for further studies on multispecies interactions in different systems beyond plant-frugivore interactions, including plant-pollinator interactions, the exploitation of plants by herbivores, and the use of carcasses by vertebrate scavengersinfo:eu-repo/semantics/publishedVersio

TReR: A Lightweight Transformer Re-Ranking Approach for 3D LiDAR Place Recognition

Autonomous driving systems often require reliable loop closure detection to guarantee reduced localization drift. Recently, 3D LiDAR-based localization methods have used retrieval-based place recognition to find revisited places efficiently. However, when deployed in challenging real-world scenarios, the place recognition models become more complex, which comes at the cost of high computational demand. This work tackles this problem from an information-retrieval perspective, adopting a first-retrieve-then-re-ranking paradigm, where an initial loop candidate ranking, generated from a 3D place recognition model, is re-ordered by a proposed lightweight transformer-based re-ranking approach (TReR). The proposed approach relies on global descriptors only, being agnostic to the place recognition model. The experimental evaluation, conducted on the KITTI Odometry dataset, where we compared TReR with s.o.t.a. re-ranking approaches such as alphaQE and SGV, indicate the robustness and efficiency when compared to alphaQE while offering a good trade-off between robustness and efficiency when compared to SGV.Comment: This preprint has been submitted to 26th IEEE International Conference on Intelligent Transportation Systems ITSC 202

Simple and efficient furfural production from xylose in media containing 1-Butyl-3-Methylimidazolium hydrogen sulfate

The acidic 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim][HSO4]) ionic liquid was explored as both a reaction medium and a catalyst in the furfural production from xylose. Preliminary experiments were carried out at 100–140 °C for 15–480 min in systems containing just xylose dissolved in [bmim][HSO4] in the absence of externally added catalysts. More than 95% xylose conversion was achieved when operating at 120 or 140 °C for 300 and 90 min, respectively; but just 36.7% of the initial xylose was converted to furfural. Operation in biphasic reaction systems (in the presence of toluene, methyl-isobutyl ketone or dioxane as extraction solvents) at 140 °C under selected conditions resulted in improved furfural production (73.8%, 80.3%, and 82.2% xylose conversion to furfural for the cited extraction solvents, respectively)

Evaluation of alternative alkali pretreatment for oat straw saccharification and fermentation

ECO-BIO 2016Introduction: Lignocellulosic biofuels production requires the sustainable pretreatment for its processing. Lime pretreatment is considered an alternative alkali pretreatment, easily to recover and inexpensive that allows to operate under milder conditions of temperature and pressure. The aim of this work was the evaluation of lime pretreatment for bioethanol production from oat straw. Methods: Oat straw was subjected to lime pretreatment at liquid to solid ratio of 10 g/g. The following operational conditions of lime pretreatment were evaluated: temperature (in the range 90-134 ºC), time (30-120 min) and Ca(OH)2/g (01-04 g/g). The pretreated oat straw was recovered by filtration, washed until pH=7 and analysed for chemical composition. The enzymatic susceptibility of lime pretreated solids was evaluated under favourable conditions of solid and enzymes loadings (25 g/g and 25 FPU of CellicTec2/g). Selected condition of lime pretreatment (134 ºC, 30 min and 0.1 g of Ca(OH)2/g of oat straw) was used for the bioethanol production by simultaneous saccharification and fermentation (14 % of solids and 20 FPU/g) using an industrial Saccharomyces cerevisiae PE-2 strain and its metabolic engineered version (MEC1133) for xylose consumption. Results and Discussion: Under selected conditions (134 ºC for 30 min and a Ca(OH)2 load of 0.1g/g) 96 % of glucan and 77 % of xylan were recovered and 42 % of delignification was achieved. Moreover, the lime pretreatment allowed enhancing the enzymatic saccharification achieving 75 % of glucan to glucose conversion and 100 % of xylan to xylose conversion. The use of MEC1133 strain increased a 20 % of ethanol concentration comparing to PE-2 obtaining 41 and 34 g/L of ethanol, respectively. This work provides a suitable process for the fractionation of oat straw. Lime pretreatment yields a pretreated raw material with high polysaccharide content susceptible to be efficiently converted into ethanol.info:eu-repo/semantics/publishedVersio