The Mercedes water Cherenkov detector Assis, P.; Bakalová, A.; Barres de Almeida, U. ...
The European physical journal. C, Particles and fields,
10/2022, Letnik:
82, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The concept of a small, single-layer water Cherenkov detector, with three photomultiplier tubes (PMTs), placed at its bottom in a
120
∘
star configuration (
Mercedes
Water Cherenkov Detector) is ...presented. The PMTs are placed near the lateral walls of the stations with an adjustable inclination and may be installed inside or outside the water volume. To illustrate the technical viability of this concept and obtain a first-order estimation of its cost, an engineering design was elaborated. The sensitivity of these stations to low energy Extensive Air Shower (EAS) electrons, photons and muons is discussed, both in compact and sparse array configurations. It is shown that the analysis of the intensity and time patterns of the PMT signals, using machine learning techniques, enables the tagging of muons, achieving an excellent gamma/hadron discrimination for TeV showers. This concept minimises the station production and maintenance costs, allowing for a highly flexible and fast installation. Mercedes Water Cherenkov Detectors (WCDs) are thus well-suited for use in high-altitude large gamma-ray observatories covering an extended energy range from the low energies, closing the gap between satellite and ground-based measurements, to very high energy regions, beyond the PeV scale.
Approximately 20,000 species of flowering plant offer mainly pollen to their pollinators, generally bees. Stamen dimorphism, a floral trait commonly present in some pollen flowers, is thought to be ...associated with exclusive pollen provision for highly effective bee pollinators. Notwithstanding, little is known about how stamen dimorphism is related to other floral morphological traits and, consequently, plant–pollinator interactions at the community scale. Here we investigated the relationship between stamen dimorphism and other floral morphological traits, as well as the interactions with pollinators in plants of Melastomataceae.
We characterized each plant species as stamen dimorphic or stamen isomorphic according to differences in size and shape between stamen sets. Data on interactions between the plants and their bee pollinators were analysed as quantitative bipartite networks.
We found that petal and style size and shape were correlated to stamen dimorphism. Stamen dimorphic species present larger flowers and less variable style shapes than stamen isomorphic species. Furthermore, stamen dimorphism is associated with higher richness of visiting bees, i.e. higher ecological generalization.
During the evolutionary history of Melastomataceae, the dependence on pollinators for fruit set has possibly favoured the evolution of larger flowers with dimorphic stamens, which in turn are able to make use of a larger spectrum of pollen‐collecting bees, leading to ecological generalization.
Stamen dimorphic species present larger flowers, have less variable style shapes and are associated with greater richness of visiting bees than stamen isomorphic species.
ABSTRACT
We investigate stellar magnetic activity from the theoretical point of view, by using stellar evolution models to calculate theoretical convective turnover times (τc) and Rossby numbers (Ro) ...for pre-main-sequence and main-sequence stars. The problem is that the canonical place where τc is usually determined (half a mixing length above the base of the convective zone) fails for fully convective stars and there is no agreement on this in the literature. Our calculations were performed with the ATON stellar evolution code. We concentrated our analysis on fully and partially convective stars motivated by recent observations of slowly rotating fully convective stars, whose X-ray emissions correlate with their Rossby numbers in the same way as in solar-like stars, suggesting that the presence of a tachocline is not required for magnetic field generation. We investigate the behaviour of τc over the stellar radius for stars of different masses and ages. As Ro depends on τc, which varies strongly with the stellar radius, we use our theoretical results to determine a better radial position at which to calculate it for fully convective stars. Using our alternative locations, we fit a sample of 847 stars in the rotation–activity diagram (LX/Lbol versus Ro) with a two-part power-law function. Our fit parameters are consistent with previous work, showing that stars with ${\rm \mathit {Ro}}\, \le \, {\rm \mathit {Ro}_{sat}}$ are distributed around a saturation level in LX/Lbol and, for stars with ${\rm \mathit {Ro}}\, \gt \, {\rm \mathit {Ro}_{sat}}$, LX/Lbol clearly decays with Ro with an exponent of −2.4 ± 0.1.
Purpose
This study aimed to develop a 3D MRI technique to assess lung ventilation in free‐breathing and without the administration of contrast agent.
Methods
A 3D‐UTE sequence with a koosh ball ...trajectory was developed for a 3 Tesla scanner. An oversampled k‐space was acquired, and the direct current signal from the k‐space center was used as a navigator to sort the acquired data into 8 individual breathing phases. Gradient delays were corrected, and iterative SENSE was used to reconstruct the individual timeframes. Subsequently, the signal changes caused by motion were eliminated using a 3D image registration technique, and ventilation‐weighted maps were created by analyzing the signal changes in the lung tissue. Six healthy volunteers and 1 patient with lung cancer were scanned with the new 3D‐UTE and the standard 2D technique. Image quality and quantitative ventilation values were compared between both methods.
Results
UTE‐based self‐gated noncontrast‐enhanced functional lung (SENCEFUL) MRI provided a time‐resolved reconstruction of the breathing motion, with a 49% increase of the SNR. Ventilation quantification for healthy subjects was in statistical agreement with 2D‐SENCEFUL and the literature, with a mean value of 0.11 ± 0.08 mL/mL for the whole lung. UTE‐SENCEFUL was able to visualize and quantify ventilation deficits in a patient with lung tumor that were not properly depicted by 2D‐SENCEFUL.
Conclusion
UTE‐SENCEFUL represents a robust MRI method to assess both morphological and functional information of the lungs in 3D. When compared to the 2D approach, 3D‐UTE offered ventilation maps with higher resolution, improved SNR, and reduced ventilation artifacts.
Demographic data are essential to assessments of the status of endangered species. However, establishing an integrated monitoring program to obtain useful data on contemporary and future population ...trends requires both the identification of priority areas and populations and realistic evaluations of the kinds of data that can be obtained under different monitoring regimes. We analyzed all known populations of a critically endangered primate, the muriqui (genus: Brachyteles) using population size, genetic uniqueness, geographic importance (including potential importance in corridor programs) and implementability scores to define monitoring priorities. Our analyses revealed nine priority populations for the northern muriqui (B. hypoxanthus) and nine for the southern muriqui (B. arachnoides). In addition, we employed knowledge of muriqui developmental and life history characteristics to define the minimum monitoring intensity needed to evaluate demographic trends along a continuum ranging from simple descriptive changes in population size to predictions of population changes derived from individual based life histories. Our study, stimulated by the Brazilian government's National Action Plan for the Conservation of Muriquis, is fundamental to meeting the conservation goals for this genus, and also provides a model for defining priorities and methods for the implementation of integrated demographic monitoring programs for other endangered and critically endangered species of primates.
•This is the first study of bioaerosols in the Athens Metro system.•We used ITS sequencing to characterise subway aerosol mycobiome diversity.•Bacterial and fungal taxa of environmental origin ...dominated the Metro station PM10.•Outdoor air and commuters are key sources of subway microbial airborne particles.
To date, few studies have examined the aerosol microbial content in Metro transportation systems. Here we characterised the aerosol microbial abundance, diversity and composition in the Athens underground railway system. PM10 filter samples were collected from the naturally ventilated Athens Metro Line 3 station “Nomismatokopio”. Quantitative PCR of the 16S rRNA gene and high throughput amplicon sequencing of the 16S rRNA gene and internal transcribed spacer (ITS) region was performed on DNA extracted from PM10 samples. Results showed that, despite the bacterial abundance (mean = 2.82 × 105 16S rRNA genes/m3 of air) being, on average, higher during day-time and weekdays, compared to night-time and weekends, respectively, the differences were not statistically significant. The average PM10 mass concentration on the platform was 107 μg/m3. However, there was no significant correlation between 16S rRNA gene abundance and overall PM10 levels. The Athens Metro air microbiome was mostly dominated by bacterial and fungal taxa of environmental origin (e.g. Paracoccus, Sphingomonas, Cladosporium, Mycosphaerella, Antrodia) with a lower contribution of human commensal bacteria (e.g. Corynebacterium, Staphylococcus). This study highlights the importance of both outdoor air and commuters as sources in shaping aerosol microbial communities. To our knowledge, this is the first study to characterise the mycobiome diversity in the air of a Metro environment based on amplicon sequencing of the ITS region. In conclusion, this study presents the first microbial characterisation of PM10 in the Athens Metro, contributing to the growing body of microbiome exploration within urban transit networks. Moreover, this study shows the vulnerability of public transport to airborne disease transmission.
Background
Subungual melanoma (SM) is rare. The lesions are thick at the time of diagnosis. Few studies have evaluated SM in Brazil.
Objective
The objective of this study was to investigate the ...factors associated with the survival of SM patients from the Brazilian National Cancer Institute.
Methods
One‐hundred and fifty‐seven patients diagnosed with SM were included in this study. We evaluated the epidemiologic, clinical, and histopathological data. Overall survival (OS) and relapse‐free survival (RFS) curves were computed using the Kaplan‐Meier method. Multivariable analyses were conducted using the Cox proportional hazard regression model.
Results
Among the 157 patients, 87 (55.4%) were female. The median age was 68 years old. Median tumor depth was 6.0 mm. Lesions were ulcerated in 94 (59.9%). OS and RFS rates for 5 years were 61.0% and 41.8%, respectively. Median follow‐up time was 28 months. The factors associated with OS were Breslow thickness and ulceration, and for RFS, they were the anatomical site, Breslow thickness, and ulceration.
Conclusion
This is the largest series of SM patients. The 5‐year OS and RFS rates were low (61.0% and 48.2%, respectively), and the main prognostic factors for OS were Breslow thickness and ulceration.
GRASPs are proteins involved in cell processes that seem paradoxical: responsible for shaping the Golgi cisternae and involved in unconventional secretion mechanisms that bypass the Golgi. Despite ...its physiological relevance, there is still a considerable lack of studies on full-length GRASPs. Our group has previously reported an unexpected behavior of the full-length GRASP from the fungus C. neoformans: its intrinsically-disordered characteristic. Here, we generalize this finding by showing that it is also observed in the GRASP from S. cerevisae (Grh1), which strongly suggests it might be a general property within the GRASP family. Furthermore, Grh1 is also able to form amyloid-like fibrils either upon heating or when submitted to changes in the dielectric constant of its surroundings, a condition that is experienced by the protein when in close contact with membranes of cell compartments, such as the Golgi apparatus. Intrinsic disorder and fibril formation can thus be two structural properties exploited by GRASP during its functional cycle.
We present a concise workflow to enhance the mass spectrometric detection of crosslinked peptides by introducing sequential digestion and the crosslink identification software xiSEARCH. Sequential ...digestion enhances peptide detection by selective shortening of long tryptic peptides. We demonstrate our simple 12‐fraction protocol for crosslinked multi‐protein complexes and cell lysates, quantitative analysis, and high‐density crosslinking, without requiring specific crosslinker features. This overall approach reveals dynamic protein–protein interaction sites, which are accessible, have fundamental functional relevance and are therefore ideally suited for the development of small molecule inhibitors.
Synopsis
A new workflow combining sequential digestion and the search software Xi increases the number of identified crosslinks in a wide range of applications. By detecting dynamic protein interactions, crosslinking is synergistic with other structural approaches and is promising for drug development.
Sequential digestion outperforms parallel digestion by shortening long peptides and thus facilitates crosslink identification.
xiSEARCH outperforms other search algorithms.
A dynamic interaction identified in the OCCM complex, and not seen before by cryoEM, is a potential target for cancer therapy.
A new workflow combining sequential digestion and the search software Xi increases the number of identified crosslinks in a wide range of applications. By detecting dynamic protein interactions, crosslinking is synergistic with other structural approaches and is promising for drug development.
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