Aedes aegypti larvae that develop in containers largely depend on plant detritus as a source of nutritional resources. However, few studies have evaluated the performance of immature individuals ...under natural amounts and quality of this food source. Here, we aimed to assess the effect of the variation in the accumulation time and amount of detritus on life history traits of Ae. aegypti under semi‐field conditions. Ae. aegypti larvae were raised with detritus collected in different sites to represent natural variability in its amount, simulating short (28 days) and long (70 days) accumulation. A control with optimal food conditions (yeast) was included. Survival, development time and wing length of adults were compared among treatments. Survival was relatively high in all treatments. Development time was similar among treatments but significantly longer and more variable in containers with the lowest detritus amounts. Wing lengths were smaller in the treatments with detritus than in the control, especially in females. The results support the hypothesis that, in a temperate region, Ae. aegypti larvae may have a nutritional limitation, at least in some containers, and emphasize the importance of performing experiments that simulate the environmental conditions to which individuals are exposed in nature.
Development times of Aedes aegypti were longer and more variable with low amounts of detritus than with higher amounts of detritus or yeast.
The amount of detritus had no effect on Ae. aegypti adult body size, and females feeding on natural detritus attained smaller body size than those fed on yeast.
The results show that Ae. aegypti larvae feeding on natural detritus may be nutritionally limited and emphasize the need for experiments that simulate natural environmental conditions.
SABRE aims to directly measure the annual modulation of the dark matter interaction rate with NaI(Tl) crystals. A modulation compatible with the standard hypothesis, in which our Galaxy is immersed ...in a dark matter halo, has been measured by the DAMA experiment in the same target material. Other direct detection experiments, using different target materials, seem to exclude the interpretation of such modulation in the simplest scenario of WIMP-nucleon elastic scattering. The SABRE experiment aims to carry out an independent search with sufficient sensitivity to confirm or refute the DAMA claim. The goal of the SABRE experiment is to achieve the lowest background rate for a NaI(Tl) experiment (order of 0.1 cpd/kg/keV
ee
in the energy region of interest for dark matter). This challenging goal could be achievable by operating high-purity crystals inside a liquid scintillator veto for active background rejection. In addition, twin detectors will be located in the northern and southern hemispheres to identify possible contributions to the modulation from seasonal or site-related effects. The SABRE project includes an initial Proof-of-Principle phase at LNGS (Italy), to assess the radio-purity of the crystals and the efficiency of the liquid scintillator veto. This paper describes the general concept of SABRE and the expected sensitivity to WIMP annual modulation.
This paper reports on the observation of the sidereal large-scale anisotropy of cosmic rays using data collected by the ARGO-YBJ experiment over 5 years (2008-2012). This analysis extends previous ...work limited to the period from 2008 January to 2009 December, near the minimum of solar activity between cycles 23 and 24. With the new data sample, the period of solar cycle 24 from near minimum to maximum is investigated. A new method is used to improve the energy reconstruction, allowing us to cover a much wider energy range, from 4 to 520 TeV. Below 100 TeV, the anisotropy is dominated by two wide regions, the so-called "tail-in" and "loss-cone" features. At higher energies, a dramatic change of the morphology is confirmed. The yearly time dependence of the anisotropy is investigated. Finally, no noticeable variation of cosmic-ray anisotropy with solar activity is observed for a median energy of 7 TeV.
In this work we present a low noise high speed readout electronics for large area Silicon Photomultipiers (SiPMs) to be used in a cryogenic environment. The board is able to manage the signals coming ...from a 25 cm
2
SiPM tile, showing ¡10% SPE resolution and wide dynamic. The sub-nanosecond timing properties make them suitable to work with the typical mixtures of Liquid Scintillators currently being used in particle and astroparticle physics experiments. The boards have been tested with several types of SiPMs from room temperature down to -70 C showing excellent single photo-electron resolution in all the enviroments. The board’s PCBs have been developed with ultra low background material in order to be used in rare event searches.
We report on the performance of commercial SiPM-based photo-detector Multi-Pixel Photon Counter (MPPC) S13360-6075CS by Hamamatsu Photonics from room temperature down to -50 °C at INFN - Sezione di ...Roma Tre. The work presented here is focused on the realization of 10 m
2
SiPM surface for the Taishan Antineutrino Observatory (TAO) near detector in the framework of the Jiangmen Underground Neutrino Observatory (JUNO) neutrino experiment.
The hadronic interaction of cosmic rays with solar atmosphere can produce high energy gamma-rays. The gamma-ray luminosity is correlated both with the flux of primary cosmic rays and the intensity of ...the solar magnetic field. The gamma-rays below 200 GeV have been observed by Fermi without any evident energy cutoff. The bright gamma-ray flux above 100 GeV has been detected only during solar minimum. The only available data in the TeV range come from the HAWC observations, however, outside the solar minimum. The ARGO-YBJ data set has been used to search for sub-TeV/TeV gamma-rays from the Sun during the solar minimum from 2008 to 2010, the same time period covered by the Fermi data. A suitable model containing the Sun shadow, solar disk emission, and inverse-Compton emission has been developed, and the chi-square minimization method was used to quantitatively estimate the disk gamma-ray signal. The result shows that no significant gamma-ray signal is detected and upper limits to the gamma-ray flux at 0.3-7 TeV are set at the 95% confidence level. In the low energy range these limits are consistent with the extrapolation of the Fermi-LAT measurements taken during solar minimum and are compatible with a softening of the gamma-ray spectrum below 1 TeV. They also provide an experimental upper bound to any solar disk emission at TeV energies. Models of dark matter annihilation via long-lived mediators predicting gamma-ray fluxes >10−7 GeV cm−2 s−1 below 1 TeV are ruled out by the ARGO-YBJ limits.
We report on a measurement of thermal neutrons, generated by the hadronic component of extensive air showers (EAS), by means of a small array of EN-detectors developed for the PRISMA project (PRImary ...Spectrum Measurement Array), novel devices based on a compound alloy of ZnS(Ag) and 6LiF. This array has been operated within the ARGO-YBJ experiment at the high altitude Cosmic Ray Observatory in Yangbajing (Tibet, 4300 m a.s.l.). Due to the tight correlation between the air shower hadrons and thermal neutrons, this technique can be envisaged as a simple way to estimate the number of high energy hadrons in EAS. Coincident events generated by primary cosmic rays of energies greater than 100 TeV have been selected and analyzed. The EN-detectors have been used to record simultaneously thermal neutrons and the air shower electromagnetic component. The density distributions of both components and the total number of thermal neutrons have been measured. The correlation of these data with the measurements carried out by ARGO-YBJ confirms the excellent performance of the EN-detector.
The ARGO-YBJ detector, located at the Yangbajing Cosmic Ray Laboratory (4300 m a. s. l., Tibet, China), was a "full coverage" (central carpet with an active area of ∼93%) air shower array dedicated ...to gamma-ray astronomy and cosmic-ray studies. The wide field of view (∼2 sr) and high duty cycle (>86%), made ARGO-YBJ suitable to search for short and unexpected gamma-ray emissions like gamma-ray bursts (GRBs). Between 2007 November 6 and 2013 February 7, 156 satellite-triggered GRBs (24 of them with known redshift) occurred within the ARGO-YBJ field of view (zenith angle θ ≤ 45°). A search for possible emission associated with these GRBs has been made in the two energy ranges 10-100 GeV and 10-1000 GeV. No significant excess has been found in time coincidence with the satellite detections nor in a set of different time windows inside the interval of one hour after the bursts. Taking into account the EBL absorption, upper limits to the energy fluence at a 99% confidence level have been evaluated, with values ranging from ∼10−5 erg cm−2 to ∼10−1 erg cm−2. The Fermi-GBM burst GRB 090902B, with a high-energy photon of 33.4 GeV detected by Fermi-LAT, is discussed in detail.
The ARGO-YBJ experiment is a full-coverage air shower detector operating at the Yangbajing International Cosmic Ray Observatory (Tibet, PR China, 4300m a.s.l.). The detector was in stable data taking ...in its full configuration from November 2007 to February 2013. More than 5×1011 events have been collected and reconstructed. Due to its characteristics (full-coverage, high segmentation, high altitude operation) the ARGO-YBJ experiment is able to investigate the cosmic ray energy spectrum in a wide energy range and offer the possibility of measuring the cosmic ray light component spectrum down to the TeV region, where direct balloon-borne measurements are available. In this work we present the measurement of the proton and helium spectra in the energy range 1–300TeV by using a large data sample collected between January 2008 and December 2011.
•We have measured the light component spectrum of cosmic rays.•The measurement has been performed by the full coverage high altitude ARGO-YBJ experiment.•The measurement covers the energy range 1–300TeV where direct measurements are available.
This article describes a design of an field-programmable gate array (FPGA) implementation of a clock and data recovery (CDR) system. The core will be integrated in the FPGA configuration for the ...front-end electronics (FEE) board of the Jiangmen underground neutrino observatory (JUNO) experiment. The front-end will be placed on the main detector, underground and underwater, making the electronics not accessible after installation. The timing and trigger system relies on a synchronous link connection over CAT5e cable (up to 100 m long) between the front-end and the back-end electronics (BEE), where a twisted-pair is dedicated to clock-forwarding. The robustness of the recovery clock system is essential for the stability of the FPGA firmware. The proposed project is intended to improve the clock recovery operation by increasing the immunity of the link to sudden electromagnetic interference (EMI). On top of this, the core allows to free a twisted-pair in the link, since the clock can be recovered from the data and there is no more need for a clock-dedicated transmission. This will optimize the link granting the possibility to implement other features. The design is based on two components: a numerically-controlled oscillator (NCO), in order to create a controlled frequency clock signal, and a digital phase detector (PD) to match the clock frequency with the data rate. NCOs are often coupled with a digital-to-analog converter (DAC) to create direct digital synthesizers (DDSs), which are able to produce analog waveforms of any desired frequency. In the presented case instead, the NCO generates a digital clock signal of an arbitrary frequency, while the PD manages this frequency by intercepting any shifting on the relative phase between the clock and the data. A phase aligner (PA) module guarantees that data are sampled in the middle of the eye pattern, which represents the optimal sampling point. The article presents an overview of the NCO-based CDR design and implementation, together with some tests and results in order to verify the CDR reliability. Moreover, in the last section, some other possible applications of the core are illustrated.
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