Cluster Analysis of Variations in the Diurnal Pattern of Grass Pollen Concentrations in Northern Europe (Copenhagen) and Southern Europe (Córdoba)

From an allergological point of view, Poaceae pollen is one of the most important type of pollen that the population is exposed to in the ambient environment. There are several studies on intra diurnal patterns in grass pollen concentrations, and agreement on the high variability. However, the method for analysing the different patterns is not yet well established. The aim of the present study is therefore to examine the method of pattern analysis by statistical clustering, as well as relating the proposed patterns to time of season and meteorological variables at two highly different biogeographical locations; Córdoba, Spain and Copenhagen, Denmark. Airborne pollen is collected by Hirst type volumetric spore traps and counted using an optical microscope at both sites. The counts were converted to two-hours concentrations and a new method based on cluster analysis was applied with the aim of determining the most frequent diurnal patterns in pollen concentrations and their dependencies of site, season and meteorological variables. Three different well defined diurnal patterns were identified at both locations. The most frequent pattern in Copenhagen was associated with days having peak pollen concentrations in the evening (maximum between18h-20h), whereas the most frequent pattern at Córdoba was associated with days having peak pollen concentrations in the afternoon (maximum between 14h-16h). These three patterns account for 70% of days with no rain and pollen concentrations above 20 grains m-3. The most frequent pattern accounts for 40% and 57% of the days in Córdoba and Copenhagen respectively. The analysis clearly shows the great variation in pollen concentration pattern, albeit a dominating pattern can be found. It was not possible to explain all the differences in the patterns by the meteorological variables when examined individual. Clustering method is estimated to be an appropriate methodology for studying aerobiological phenomena with high variability

Diagnostic accuracy of sliding sign for detecting pouch of Douglas obliteration and bowel involvement in women with suspected endometriosis: systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to evaluate the diagnostic accuracy of the sliding sign on transvaginal ultrasound (TVS) in detecting pouch of Douglas obliteration and bowel involvement in patients with suspected endometriosis, using laparoscopy as the reference standard

Beware the recent past: a bias in spectral energy distribution modelling due to bursty star formation

We investigate how the recovery of galaxy star formation rates (SFRs) using energy-balance spectral energy distribution (SED) fitting codes depends on their recent star formation histories (SFHs). We use the Magphys and Prospector codes to fit 6,706 synthetic spectral energy distributions (SEDs) of simulated massive galaxies at $1 < z < 8$ from the Feedback in Realistic Environments (FIRE) project. We identify a previously unknown systematic error in the Magphys results due to bursty star formation: the SFR estimates of individual galaxies can differ from the true values by as much as 1 dex, at large statistical significance ($>5\sigma$), depending on the details of their recent SFH. The SFRs inferred using Prospector do not exhibit this trend, likely because unlike Magphys, Prospector uses non-parametric SFHs. We urge caution when using Magphys, or other codes assuming parametric SFHs, to study galaxies where the average SFR may have changed significantly over the last $\sim$100 Myr, such as those which have recently quenched their star formation or those experiencing an ongoing burst. This concern is especially relevant, for example, when fitting JWST observations of very high-redshift galaxies.Comment: 5 pages, 3 figures, submitted to MNRAS Letter

Tree genetic resources at risk in South America: A spatial threat assessment to prioritize populations for conservation

Background Humans threat the populations of tree species by overexploitation, deforestation, land use change, and climate change. We present a novel threat assessment at intraspecific level to support the conservation of genetic resources of 80 socioeconomically viable tree species in South America. In this assessment, we evaluate the threat status of Ecogeographic Range Segments (ERSs). ERSs are groups of populations of a specific species in a certain ecological zone of a particular grid cell of a species’ geographic occupancy. Methods We used species location records to determine the species distributions and species‐specific ERSs. We distinguished eight threat situations to assess the risk of extirpation of the ERSs of all 80 species. These threat situations were determined by large or little tree cover, low or high human pressure, and low or high climate change impact. Available layers of tree cover and threats were used to determine the levels of fragmentation and direct human pressure. Maxent niche modelling with two Global Circulation Models helped determining climate change impact by the 2050s. Results When all 80 species are considered, in total, 59% of the ERSs are threatened by little tree cover or high human pressure. When climate change is also considered, then 71‐73% of the ERSs are threatened. When an increased risk of extirpation of populations outside protected areas is considered, then 84–86% of the ERSs are threatened. Seven species warrant special attention because all their ERSs are threatened across their whole distribution in South America: Balfourondendron riedelianum, Cariniana legalis, Dalbergia nigra, Handroanthus pulcherrimus, Pachira quintana, Prosopis flexuosa, and Prosopis pallida. Conclusions Our results confirm the urgency to set up a regional action plan for the conservation of tree genetic resources in South America. With this threat assessment, we aim to support governments and organizations who are taking up this task

Beware the recent past: a bias in spectral energy distribution modelling due to bursty star formation

© 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We investigate how the recovery of galaxy star formation rates (SFRs) using energy-balance spectral energy distribution (SED) fitting codes depends on their recent star formation histories (SFHs). We use the Magphys and Prospector codes to fit 6,706 synthetic spectral energy distributions of simulated massive galaxies at $1 5\sigma$), depending on the details of their recent SFH. SFRs inferred using Prospector with non-parametric SFHs do not exhibit this trend. We show that using parametric SFHs (pSFHs) causes SFR uncertainties to be underestimated by a factor of up to $5\times$. Although this undoubtedly contributes to the significance of the systematic, it cannot explain the largest biases in the SFRs of the starbursting galaxies, which could be caused by details of the stochastic prior sampling or the burst implementation in the Magphys libraries. We advise against using pSFHs and urge careful consideration of starbursts when SED modelling galaxies where the SFR may have changed significantly over the last ~100 Myr, such as recently quenched galaxies, or those experiencing a burst. This concern is especially relevant, e.g. when fitting JWST observations of very high-redshift galaxies.Peer reviewe

Comparative study of airborne pollen counts located in different areas of the city of Cordoba (south-western Spain

Abstract Airborne pollen counts are mainly determined using a volumetric suction sampler based on the impact principle, that is, a Hirst-type spore trap. As a consequence of their volumetric nature, samplers detect pollen from a wide area, and therefore, a single sampler is frequently used to acquire information on airborne pollen counts for the whole city. The main goal of the present study was to compare airborne pollen counts at two sites located at opposite ends (south-west vs. north-east) of the southern Spanish city of Córdoba, to assess the advantages and disadvantages of using more than one sampler in the city. Also, a comparative study was carried out using two samplers at the same site, in order to confirm the efficiency of the samplers. Results revealed that data from one volumetric sampler-located within a city of medium size with uniform topography and vegetation conditions-are sufficient to establish monitoring of the main airborne pollen types, the pollen seasons involved and the timing of peak counts. For clinical studies, however, data on pollen counts in specific areas of the city may be of value, since pollen intensity may vary from one district to another, mainly in the case of ornamental plants with a local distribution inside the city. Comparison of data obtained by the two samplers running at the same site indicated that potential inter-site differences could not be attributed to differences in sampler efficiency

Landau-Zener and Rabi oscillations in the spin-dependent conductance

We describe the spin-dependent quantum conductance in a wire where a magnetic field is spatially modulated. The changes in direction and intensity of the magnetic field acts as a perturbation that mixes spin projections. This is exemplified by a ferromagnetic nanowire. There the local field varies smoothly its direction generating a domain wall (DW) as described by the well known Cabrera-Falicov model. Here, we generalize this model to include also a strength modulation. We identify two striking diabatic regimes that appear when such magnetic inhogeneity occurs. 1) If the field strength at the DW is weak enough the local Zeeman energies result in an avoided crossing. Thus, the spin flip probability follows the Landau-Zener formula. 2) For strong fields, the spin-dependent conductance shows oscillations as function of the DW width. We interpret them in terms of Rabi oscillations. Time and length scales obtained from this simplified view show an excellent agreement with the exact dynamical solution of the spin-dependent transport. These results remain valid for other situations involving modulated magnetic structures and thus they open new prospects for the use of quantum interferences in spin-based devices.http://iopscience.iop.org/0295-5075/105/1/17005publishedVersionFil: Fernández Alcázar, Lucas Jonatan. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Fernández Alcázar, Lucas Jonatan. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Pastawski, Horacio Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Pastawski, Horacio Miguel. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Física de los Materiales Condensado

Solvent-assisted in situ synthesis of cysteamine-capped silver nanoparticles

Silver nanoparticles offer a huge potential for biomedical applications owing to their exceptional properties and small size. Specifically, cysteamine-capped silver nanoparticles could form the basis for new anticancer therapies combining the cytotoxic effect of the silver core with the inherent antitumor activity of cysteamine, which inhibit cancer cell proliferation and suppress invasion and metastasis. In addition, the capability of the cysteamine coating monolayer to couple a variety of active principles and targeting (bio)molecules of interest proves key to the tailoring of this platform in order to exploit the pathophysiology of specific tumor types. Nevertheless, the chain length and conformational flexibility of cysteamine, together with its ability to attach to the surface of silver nanoparticles via both the thiol and the amine group, have made the in situ synthesis of these particles an especially challenging task. Herein we report a solvent-assisted in situ synthesis method that solves this problem. The obtained nanoparticles have been fully characterized by UV–visible absorption spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, electron diffraction measurement, high resolution transmission electron microscopy, scanning transmission electron microscopy, energy dispersive x-ray spectroscopy nanoanalysis, and dynamic light scattering measurement. Our synthesis method achieves extremely high yield and surface coating ratio, and colloidal stability over a wide range of pH values including physiological pH. Additionally, we have demonstrated that cysteamine-capped nanoparticles obtained by this method can be conjugated to an antibody for active targeting of the epidermal growth factor receptor, which plays an important role in the pathogenesis and progression of a wide variety of tumors, and induce cell death in human squamous carcinoma cells. We believe this method can be readily extended to combinations of noble metals and longer chain primary, secondary, ternary or even quaternary aminethiolsEspaña, Junta de Andalucía P10- FQM-6615España, Ministerio de Economia y Competitividad CTP2016-80206-