Cladocerans are a diverse group of species that show rapid responses to changes in environmental conditions. This adaptive capacity has important implications for egg production and life cycle, ...especially in transitory environments such as temporary waterbodies. The present study investigated the life history and egg production of Alona gutatta Sars, 1862 (Crustacea, Cladocera), an abundant and frequent species from a high-altitude temporary pond (Lagoa Seca, Minas Gerais, Brazil). Newly hatched neonates were monitored in relation to time of maturation, number of eggs produced per female and time of survival. Neonates required a mean of 8 days to mature. A. guttata survived for a mean of 30.9 ± 8.1 days and produced 2 eggs per brood, generating a mean of 10.95 ± 6.41 neonates during the entire life cycle. The rapid development, short time to produce eggs and long life cycle are important adaptations to the adverse environmental conditions of temporary aquatic environments, which can contribute to the rapid colonization of Alona guttata in transitory ecosystems.
High-energy astrophysics polarimetry may significantly benefit from e-ASTROGAM and from AMEGO mission proposals, since to date limited polarimetric measurements were performed in this domain, ...exclusively under 1 MeV. The polarimetric potential of both missions was analyzed in the Compton regime by Monte Carlo mass model simulations with MEGAlib toolkit. The performance of e-ASTROGAM was analyzed by simulating Si tracker and calorimeter alternative configurations and detection materials, within missions’ volume, mass and power margins. The modulation polarimetric factor,
Q
, and the MDP were calculated for different polarized source types and for variable incidence angle measurement conditions. Finally, the polarimetric performances of both instruments was compared and analyzed.
Q
modulation factors obtained ranged between ~0.2 and ~0.4 in the 0.2–2.0 MeV band and MDP ~0.65% was estimated for a 100% polarized Crab type source, 1 Ms. observation time and 3
σ
significance.
In this work we describe the ongoing construction of a Time Projection Chamber-based (TPC) spectrometer for light charged particles utilising magnetic field as a means for energy measurement, ...combining Multi Wire Proportional Chambers (MWPC) with Timepix3 pixel detectors for improved spatial and angular resolution. The spectrometer will be operated at the Institute of Experimental and Applied Physics (IEAP) Van-de-Graaff facility with the goal of verifying the so-called ATOMKI anomaly (deviation in the distribution of the opening angle between electrons and positrons originating in internal pair creations – IPC – in the decay of 8Be and 4He excited nuclei). Description of the detectors is provided along with a few results.
A new experimental system was recently developed to measure the mobility of both positive and negative ions: the Dual-Polarity Ion Drift Chamber (DP-IDC). In this work, we present a detailed ...description of the experimental setup and technique used, as well as the initial studies carried out. The reduced ion mobilities of SF5− and SF6− were measured in pure SF6, SF6-CF4 and SF6-N2, for pressures between 10 and 30 Torr and reduced electric fields ranging from 10 to 40 Td. The results were compared with experimental and theoretical data available, and a good performance was found. The study of the mobility of positive ions in Ne-CF4 gas mixtures was also performed, with the results obtained showing a good agreement with those determined in a similar setup previously developed by our group. The importance of this type of studies is also discussed, along with the future prospects for this experimental system.
Operation of a TPC using the SAMPA chip integrated in the SRS de Souza, Geovane G.A.; Cortez, André F.V.; Penteado, Cesar G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2023, Letnik:
1045
Journal Article
Recenzirano
The SAMPA chip is an ASIC originally designed for the ALICE experiment at CERN and has been adopted by other large experiments. The offer of such systems for smaller, though scalable, experiments and ...the versatility of this ASIC has pushed towards its implementation as a front-end readout chip for the Scalable Readout System (SRS). In this work we present the first results of the integration of SAMPA in the SRS. To test the electronics and the readout capability a small Time Projection Chamber (10×10×8cm3) was built and cosmic rays were used to generate tracks and to develop the data construction.
A new experimental system was recently developed to measure the mobility of both positive and negative ions: the Dual-Polarity Ion Drift Chamber (DP-IDC). This system is intended to better understand ...the transport properties of ions in gases relevant for the performance of large volume gaseous detectors like the Negative Ion Time Projection Chambers (NITPCs). In this work, we present a description of the experimental setup and technique used, and the initial studies carried out in Xe–SF6 mixtures, whose interest has attracted attention as a possible alternative in searches for the neutrinoless double-beta decay.
New strategies to manage the pool of potential donors are needed to increase organ donation rates. The purpose of the study was to identify the main causes of lack of organ donation and to identify ...the sociodemographic and clinical profiles of potential organ donors in an area of northeastern Brazil.
We conducted a cross-sectional, retrospective, observational study between November 2015 and January 2017.
A total of 150 potential donors were included in the sample. The main cause of death among potential donors was hemorrhagic stroke (35.3%). Hypertension was the most prevalent comorbidity (25.6%). Family member's refusal was cited as the most common reason for not performing organ donation (49.4%). Among the causes of family member's refusal, the most prevalent was declaration of non-consent in life (23%), followed by family disagreement (20.3%).
There is clearly a need for public educational efforts with regard to organ donation. Educational advertising campaigns can help improve the authorization rate of organ donation.
Experimental ion mobility measurements for the LCTPC Collaboration Cortez, A.F.V.; Santos, M.A.G.; Veenhof, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
Measuring the mobility of ions in gases is relevant in several areas, from physics to chemistry, e.g. in gaseous radiation detectors modelling and in the understanding of the pulse shape formation. ...One of these examples is the upcoming LCTPC (Linear Collider TPC) for the International Linear Collider (ILC), where a gating device will be installed at a certain distance from the gas amplification stage to neutralize the ions produced. Knowing the ion mobility will allow to calculate this distance and to ensure a high ion reduction while minimizing the thickness of the end plate. This work focuses on measurements of positive ion mobility for mixtures of interest for the LCTPC, more specifically Ar-CF4-iC4H10 (95-3-2).
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