We developed a radio interferometric technique for the observation of extensive air showers initiated by cosmic particles. In this proof-of-principle study we show that properties of extensive air ...showers can be derived with high accuracy in a straightforward manner. When time synchronisation below
∼
1 ns between different receivers can be achieved, direction reconstruction resolution of
<
0
.
2
∘
and resolution on the depth of shower maximum of
<
10
g/cm
2
are obtained over the full parameter range studied, with even higher accuracy for inclined incoming directions. In addition, by applying the developed method to dense arrays of radio antennas, the energy threshold for the radio detection of extensive air showers can be significantly lowered. The proposed method can be incorporated in operational and future cosmic particle observatories and with its high accuracy it has the potential to play a crucial role in unravelling the composition of the ultra-high-energy cosmic-particle flux.
► Predictions for radio pulses emitted by extensive air showers obtained in a full MC simulation (ZHAireS). ► Results compatible with superposition of geomagnetic and charge excess radio emission. ► ...Geometry coupled to relativistic effects play prominent role. ► Toy model developed. Variable refractive index.
We present predictions for the radio pulses emitted by extensive air showers using ZHAireS, an AIRES-based Monte Carlo code that takes into account the full complexity of ultra-high energy cosmic-ray induced shower development in the atmosphere, and allows the calculation of the electric field in both the time and frequency domains. We do not presuppose any emission mechanism and our results are compatible with a superposition of geomagnetic and charge excess radio emission effects. We investigate the polarization of the electric field as well as the effects of the refractive index
n and shower geometry on the radio pulses. We show that geometry, coupled to the relativistic effects that appear when using a realistic refractive index
n
>
1, play a prominent role on the radio emission of air showers.
There has been a recent surge in interest in the detection of τ-lepton-induced air showers from detectors at altitude. When a τ neutrino (ντ) enters the Earth, it produces τ leptons as a result of ...nuclear charged-current interactions. In some cases, this process results in a τ lepton exiting the surface of the Earth, which can subsequently decay in the atmosphere and produce an extensive air shower. These upward-going air showers can be detected via fluorescence, optical Cherenkov, or geomagnetic radio emission. Several experiments have been proposed to detect these signals. We present a comprehensive simulation of the production of τ leptons by ντ’s propagating through Earth to aid the design of future experiments. These simulations for ντ’s and leptons in the energy range from 1015 eV to 1021 eV treat the full range of incidence angles from Earth-skimming to diametrically traversing. Propagation of ντ’s and leptons includes the effects of rock and an ocean or ice layer of various thicknesses. The interaction models include ντ regeneration and account for uncertainties in the Standard Model neutrino cross section and in the photonuclear contribution to the τ energy-loss rate.
There is growing evidence in the literature suggesting that caste differentiation in the stingless bee, Melipona scutellaris, and other bees in the genus Melipona, is triggered by environmental ...signals, particularly a primer pheromone. With the proper amount of food and a chemical stimulus, 25% of females emerge as queens, in agreement with a long-standing "two loci/two alleles model" proposed in the 1950s. We surmised that these larvae must be equipped with an olfactory system for reception of these chemical signals. Here we describe for the first time the diversity of antennal sensilla in adults and the morphology of larvae of M. scutellaris. Having found evidence for putative olfactory sensilla in larvae, we next asked whether olfactory proteins were expressed in larvae. Since the molecular basis of M. scutellaris is still unknown, we cloned olfactory genes encoding chemosensory proteins (CSP) and odorant-binding proteins (OBPs) using M. scutellaris cDNA template and primers designed on the basis CSPs and OBPs previously reported from the European honeybee, Apis mellifera. We cloned two CSP and two OBP genes and then attempted to express the proteins encoded by these genes. With a recombinant OBP, MscuOBP8, and a combinatorial single-chain variable fragment antibody library, we generated anti-MscuOBP8 monoclonal antibody. By immunohistochemistry we demonstrated that the anti-MscuOBP8 binds specifically to the MscuOBP8. Next, we found evidence that MscuOBP8 is expressed in M. scutellaris larvae and it is located in the mandibular region, thus further supporting the hypothesis of olfactory function in immature stages. Lastly, molecular modeling suggests that MscuOBP8 may function as a carrier of primer pheromones or other ligands.
With the advent of genomic sequences and next-generation sequencing technologies (RNA-Seq), multiple repertoires of olfactory proteins in various insect species are being unraveled. However, ...functional analyses are lagging behind due in part to the lack of simple and reliable methods for heterologous expression of odorant receptors (ORs). While the Xenopus oocyte recording system fulfills some of this lacuna, this system is devoid of other olfactory proteins, thus testing only the “naked” ORs. Recently, a moth OR was expressed in the majority of neurons in the antennae of the fruit fly using Orco-GAL4 to drive expression of the moth OR. Electroantennogram (EAG) was used to de-orphanize the moth OR, but generic application of this approach was brought to question. Here, we describe that this system works with ORs not only from taxonomically distant insect species (moth), but also closely related species (mosquito), even when the fruit fly has highly sensitive innate ORs for the odorant being tested. We demonstrate that Orco-GAL4 flies expressing the silkworm pheromone receptor, BmorOR1, showed significantly higher responses to the sex pheromone bombykol than the control lines used to drive expression. Additionally, we show that flies expressing an OR from the Southern house mosquito, CquiOR2, gave significantly stronger responses to the cognate odorants indole and 2-methylphenol than the “background noise” recorder from control lines. In summary, we validate the use of Orco-GAL4 driven UAS-OR lines along with EAG analysis as a simple alternative for de-orphanization and functional studies of insect ORs in an intact olfactory system.
The Beamforming Elevated Array for COsmic Neutrinos (BEACON) is a planned neutrino telescope designed to detect radio emission from upgoing air showers generated by ultrahigh energy tau neutrino ...interactions in the Earth. This detection mechanism provides a measurement of the tau flux of cosmic neutrinos. We have installed an 8-channel prototype instrument at high elevation at Barcroft Field Station, which has been running since 2018, and consists of 4 dual-polarized antennas sensitive between 30–80 MHz, whose signals are filtered, amplified, digitized, and saved to disk using a custom data acquisition system (DAQ). The BEACON prototype is at high elevation to maximize effective volume and uses a directional beamforming trigger to improve rejection of anthropogenic background noise at the trigger level. Here we discuss the design, construction, and calibration of the BEACON prototype instrument. We also discuss the radio frequency environment observed by the instrument, and categorize the types of events seen by the instrument, including a likely cosmic ray candidate event.
This work presents a use case of building a data visualization interface for open-access repositories. The case in the analysis is the Brazilian Digital Library of Theses and Dissertations (BDTD). ...From the almost 670,000 records of BDTD, one applies statistical methods using the language R. One of the visualization packages of R is called Shiny, which makes it easy to build interactive web applications straight from R. Through the app, a user can visualize data in a fast and customizable way. It could help to keep track of metadata and usage statistics over the repositories and also can be applied to discovering scientific information, such as bibliographic data and lists of specialists in a certain research domain. These data visualization tools can stimulate others to create open repositories and join either national, regional or international repositories networks.
Cosmic neutrinos are expected to include a significant flux of tau neutrinos due to flavor mixing over astronomical length scales. However, the tau-neutrino content of astrophysical neutrinos is ...poorly constrained and a significant flux of cosmogenic tau neutrinos awaits discovery. Earth-skimming tau neutrinos undergo charged-current interactions that result in a tau lepton exiting the Earth. The tau lepton decay generates anextensive air shower and geomagnetic radio emission. To target the tau neutrinos, we present a new tau neutrino detector concept that uses phased antenna arrays placed on high elevation mountains. Simulation studies indicate that a modest array size and small number of stations can achieve competitive sensitivity, provided the receivers are at highs enough elevation.
Resumo Enquanto a pesquisa-ação busca a transformação de uma realidade tal como ela é, a popularização da ciência visa inserir os cidadãos em um processo decisório e participativo, retirando-os da ...situação de usuários compulsórios dos produtos da ciência e tecnologia, passivos e invisibilizados. A tese defendida neste ensaio é a de que a pesquisa-ação pode colaborar com a popularização da ciência, de modo que haja apropriação do conhecimento pelos participantes não cientistas e haja, também, uma mudança de sujeitos passivos para sujeitos críticos e de agentes individuais para agentes sociais. A partir de uma metodologia de natureza reflexiva, interpretativa e crítica da realidade estudada, a conclusão é que todos aqueles envolvidos com a ciência devem considerar a utilização mais frequente da pesquisa-ação em suas práticas de extensão e pesquisa. Esta parece ser a chave para quem busca uma ciência democrática e inclusiva.
Abstract While action research seeks to transform reality as it is, the popularization of science aims to insert citizens in decision-making and participatory process, removing them from the situation of compulsory users of science and technology products, who are passive and made invisible. The thesis defended in this essay is that action research can contribute to science popularization, so that there can be an appropriation of knowledge by non-scientific participants, as well as a change from passive subjects to critical subjects and individual agents for social agents. Based on a methodology of a reflexive, interpretative and critical nature of the studied reality, the conclusion is that all those involved with science should consider the more frequent use of action research in their extension and research practices. This seems to be the key for anyone looking for democratic and inclusive science.
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