1,352 research outputs found
LATTES: a novel detector concept for a gamma-ray experiment in the Southern hemisphere
The Large Array Telescope for Tracking Energetic Sources (LATTES), is a novel
concept for an array of hybrid EAS array detectors, composed of a Resistive
Plate Counter array coupled to a Water Cherenkov Detector, planned to cover
gamma rays from less than 100 GeV up to 100 TeVs. This experiment, to be
installed at high altitude in South America, could cover the existing gap in
sensitivity between satellite and ground arrays.
The low energy threshold, large duty cycle and wide field of view of LATTES
makes it a powerful tool to detect transient phenomena and perform long term
observations of variable sources. Moreover, given its characteristics, it would
be fully complementary to the planned Cherenkov Telescope Array (CTA) as it
would be able to issue alerts.
In this talk, a description of its main features and capabilities, as well as
results on its expected performance, and sensitivity, will be presented.Comment: Proceedings of the 35th International Cosmic Ray Conference
(ICRC2017), Busan, South Korea. Presented by R. Concei\c{c}\~{a}o. 8 pages;
v2: correct affiliation + journal referenc
LATTES: A new gamma-ray detector concept for South America
Currently the detection of Very High Energy gamma-rays for astrophysics rely on the measurement of the Extensive Air Showers (EAS) either using Cherenkov detectors or EAS arrays with larger field of views but also larger energy thresholds. In this talk we present a novel hybrid detector concept for a EAS array with an improved sensitivity in the lower energies (~ 100 GeV). We discuss its main features, capabilities and present preliminary results on its expected perfomances and sensitivities.This wide field of view experiment is planned to be installed at high altitude in South America making it a complementary project to the planned Cherenkov telescope experiments and a powerful tool to trigger further observations of variable sources and to detect transients phenomena
Adenomatous polyposis coli regulates radial axonal sorting and myelination in the PNS
The tumor suppressor protein adenomatous polyposis coli (APC) is multifunctional – it participates in the canonical Wnt/β-catenin signal transduction pathway as well as modulating cytoskeleton function. Although APC is expressed by Schwann cells, the role that it plays in these cells and in the myelination of the peripheral nervous system (PNS) is unknown. Therefore, we used the Cre-lox approach to generate a mouse model in which APC expression is specifically eliminated from Schwann cells. These mice display hindlimb weakness and impaired axonal conduction in sciatic nerves. Detailed morphological analyses revealed that APC loss delays radial axonal sorting and PNS myelination. Furthermore, APC loss delays Schwann cell differentiation in vivo, which correlates with persistent activation of the Wnt signaling pathway and results in perturbed extension of Schwann cell processes and disrupted lamellipodia formation. In addition, APC-deficient Schwann cells display a transient diminution of proliferative capacity. Our data indicate that APC is required by Schwann cells for their timely differentiation to mature, myelinating cells and plays a crucial role in radial axonal sorting and PNS myelination
Exploiting Cherenkov Radiation With BGO-Based Metascintillators
[EN] In time-of-flight positron emission tomography (TOF-PET), the timing capabilities of the scintillation-based detector play an important role. An approach for fast timing is using the so-called metascintillators, which combine two materials leading to the synergistic blending of their favorable characteristics. An added effect for BGO-based metascintillators is taking advantage of better transportation of Cherenkov photons through UV-transparent materials such as plastic (type EJ232). To prove this, we use an optimized Coincidence Time Resolution (CTR) setup based on electronic boards with two output signals (timing and energy) and near-ultraviolet (NUV) and vacuum-ultraviolet (VUV) silicon photomultipliers (SiPMs) from Fondazione Bruno Kessler (FBK), along with different coupling materials. As a reference detector, we employed a 3x3x5-mm(3) LYSO:Ce,Ca crystal pixel coupled with optical grease to an NUV-HD SiPM. The evaluation is based on low-threshold rise time, energy and time of arrival of event datasets. Timing results of a BGO/EJ232 3x3x15-mm(3) metapixel show detector time resolutions (DTRs) of 159 ps for the full photopeak. We demonstrate the possibility of event discrimination using subsets with different DTR from the rise time distributions (RTDs). Finally, we present the synergistic capability of metascintillators to enhance Cherenkov photons detection when used along with VUV-sensitive SiPMs.This work was supported in part by the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Program (4D-PET) under Grant 695536, and in part by the Brazilian Funding Agency Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) under Grant 202378/2020-9.Latella, R.; González Martínez, AJ.; Bonifacio, DAB.; Kovylina-Zabyako, M.; Griol Barres, A.; Benlloch Baviera, JM.; Lecoq, P.... (2023). Exploiting Cherenkov Radiation With BGO-Based Metascintillators. IEEE Transactions on Radiation and Plasma Medical Sciences. 7(8):810-818. https://doi.org/10.1109/TRPMS.2023.33105818108187
LATTES: A new gamma-ray detector concept for South America
In this contribution we discuss the main features and capabilities of a novel hybrid-detector concept for a gamma extensive air-shower array with improved sensitivity towards the lower energies (100GeV). Preliminary results on its expected perfomance and sensitivity are presented. This wide field-of-view experiment is planned to be installed at high altitude in South America making it a complementary project to the planned Cherenkov telescope experiments and a powerful tool to trigger further observations of variable sources and to detect transient phenomena
Label-free optical biosensing with slot-waveguides.
We demonstrate label-free molecule detection by using an integrated biosensor based on a Si3N4 /SiO2 slotwaveguide microring resonator. Bovine serum albumin (BSA) and anti-BSA molecular binding events on the sensor surface are monitored through the measurement of resonant wavelength shifts with varying biomolecule concentrations. The biosensor exhibited sensitivities of 1.8 and 3.2 nm/ _ng/mm2_ for the detection of anti-BSA and BSA, respectively. The estimated detection limits are 28 and 16 pg/mm2 for anti-BSA and BSA, respectively, limited by wavelength resolutio
Single-cell isoform RNA sequencing characterizes isoforms in thousands of cerebellar cells
Full-length RNA sequencing (RNA-Seq) has been applied to bulk tissue, cell lines and sorted cells to characterize transcriptomes1–11, but applying this technology to single cells has proven to be difficult, with less than ten single-cell transcriptomes having been analyzed thus far12,13. Although single splicing events have been described for ≤200 single cells with statistical confidence14,15, full-length mRNA analyses for hundreds of cells have not been reported. Single-cell short-read 3′ sequencing enables the identification of cellular subtypes16–21, but full-length mRNA isoforms for these cell types cannot be profiled. We developed a method that starts with bulk tissue and identifies single-cell types and their full-length RNA isoforms without fluorescence-activated cell sorting. Using single-cell isoform RNA-Seq (ScISOr-Seq), we identified RNA isoforms in neurons, astrocytes, microglia, and cell subtypes such as Purkinje and Granule cells, and cell-type-specific combination patterns of distant splice sites6–9,22,23. We used ScISOr-Seq to improve genome annotation in mouse Gencode version 10 by determining the cell-type-specific expression of 18,173 known and 16,872 novel isoforms
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