The accurate calibration of photomultiplier tubes is critical in a wide variety of applications for which it is necessary to know the absolute number of detected photons or precisely determine the ...resolution of the signal. Conventional calibration methods rely on fitting the photomultiplier response to a low intensity light source with analytical approximations to the single photoelectron distribution. We show that this approach often leads to biased estimates due to an inability to model the full distribution accurately, especially at low charge values. We present a simple statistical method to extract the relevant single photoelectron calibration parameters (first two central moments) without making any assumptions about the underlying single photoelectron distribution. We illustrate the use of this method through the calibration of a Hamamatsu R11410 photomultiplier tube and study the accuracy and precision of the method using Monte Carlo simulations. The method is found to have significantly reduced bias compared to conventional methods and works under a wide range of light intensities, making it suitable for the simultaneous calibration of large arrays of photomultiplier tubes where uniform illumination may not be possible.
1. Current anthropogenic disturbances have changed natural environments, broadly impacting ecosystem services and functions. Here, the authors focused on the secondary dispersal of diaspores by ants, ...which serve an important ecological function in the natural regeneration of degraded habitats.
2. The authors experimentally studied the effects of vegetation suppression and soil disturbance on (i) diaspore removal, (ii) the quality of secondary removal, and (iii) the structure of interaction networks between ants and diaspores. The authors tested whether the disturbance affected the species richness of seed removers, diaspore removal rate, removal distance and time, and removal effectiveness. Additionally, the authors tested whether the structure of ant‐diaspore networks, that is, specialisation, modularity and robustness, is altered by soil disturbance. To do that, the authors studied three degraded and three preserved areas in the Brazilian Cerrado.
3. The authors observed 25 ant species interacting with the diaspores. Disturbance did not affect ant species richness, removal distance or removal rate, but ants took twice as long to remove the diaspores in the preserved habitat. The frequency of interaction networks was higher in the preserved habitat, and the effectiveness of species in removing the diaspores differed between habitats. Surprisingly, the authors observed that ants considered effective dispersers mostly occurred in degraded habitats, highlighting the potential of myrmecochory in the regeneration of impacted environments.
4. The findings point to the potential of ants in acting as secondary seed dispersal, improving the restoration of areas highly impacted by soil disturbance. Moreover, this study contributes to understanding the effects of anthropogenic disturbances on ecological interactions and ecosystem functions.
Anthropogenic disturbances reshape the structure of ant‐diaspore networks.
Soil disturbance affects secondary seed removal dynamics.
Ants can mediate important ecological functions for natural regeneration.
In order to truly examine critical cultural and social issues pertaining to young people, researchers must find ways to overcome the ways in which young people naturally filter their responses when ...speaking with adults, as these filters may limit what researchers are able to discover through interviews and focus groups. Working through theatre offers the opportunity for researcher and participant to co-construct knowledge. Drama workshops and the creation of a theatrical performance creates a community in which ideas and questions can be deeply examined and self-filtering and censorship mitigated; participant voice is centered and privileged. For seven weeks, I worked with thirteen high school girls to explore issues of identity through a devised theatre performance. My intent was to examine the ways arts-based research might provide more insight than traditional qualitative methods. This article discusses how working through theatre provided a space in which the girls I worked with felt more comfortable expressing their uncensored thoughts and opinions and offers a deeper insight into the ways working through the arts provides a model for participatory research that yields deep and nuanced understandings.
To assess the presence of pulmonary embolism and inflammation after polidocanol foam injection into the peripheral veins of rabbits.
The animals were treated with polidocanol foam (1 or 3 mg/kg) or ...vehicle. Early (15 minutes) and late (30 days) animals were evaluated by perfusional lung scintigraphy and histopathological examination.
In the control group no alterations were found. After polidocanol foam injection it was observed that an important reduction of pulmonary perfusion in the early periods, was mainly in the left lung (P < 0.001), with consequent embolism in the histological evaluation. In late periods it was observed that the presence of thrombus was with fibrin in small veins, compatible with chronic thrombus and the presence of chronic pulmonary inflammation.
The injection of polidocanol foam in experimental animals can induce venous embolism and chronic inflammatory infiltration.
Delayed single- and few-electron emissions plague dual-phase time projection chambers, limiting their potential to search for light-mass dark matter. This paper examines the origins of these events ...in the XENON1T experiment. Characterization of the intensity of delayed electron backgrounds shows that the resulting emissions are correlated, in time and position, with high-energy events and can effectively be vetoed. In this work we extend previous S2-only analyses down to a single electron. From this analysis, after removing the correlated backgrounds, we observe rates <30 events/(electron×kg×day) in the region of interest spanning 1 to 5 electrons. We derive 90% confidence upper limits for dark matter-electron scattering, first direct limits on the electric dipole, magnetic dipole, and anapole interactions, and bosonic dark matter models, where we exclude new parameter space for dark photons and solar dark photons.
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