A Strong Pulsing Nature of Negative Intracloud Dart Leaders Accompanied by Regular Trains of Microsecond-Scale Pulses

We report the first observations of negative intracloud (IC) dart-stepped leaders accompanied by regular trains of microsecond-scale pulses, simultaneously detected by shielded broadband magnetic loop antennas and the radio telescope Low Frequency Array (LOFAR). Four investigated pulse trains occurred during complicated IC flashes on 18 June 2021, when heavy thunderstorms hit the Netherlands. The pulses within the trains are unipolar, a few microseconds wide, and with an average inter-pulse interval of 5–7 μs. The broadband pulses perfectly match energetic, regularly distributed, and relatively isolated bursts of very high frequency sources localized by LOFAR. All trains were generated by negative dart-stepped leaders propagating at a lower speed than usual dart leaders. They followed channels of previous leaders occurring within the same flash several tens of milliseconds before the reported observations. The physical mechanism remains unclear as to why we observe dart-stepped leaders, which show mostly regular stepping, emitting energetic microsecond-scale pulses.</p

The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses

The contents of the colon of the Tyrolean Iceman who lived Ga. 5300 years ago include muscle fibres, cereal remains, a diversity of pollen, and most notably that of the hop hornbeam (Ostrya carpinifolia) retaining cellular contents, as well as a moss leaf (Neckera complanata) and eggs of the parasitic whipworm (Trichuris trichiura). Based almost solely on stable isotope analyses and ignoring the work on the colon contents, two recently published papers on the Iceman's diet draw ill- founded conclusions about vegetarianism and even veganism. Neither the pollen nor the moss is likely to have been deliberately consumed as food by the Iceman. All the available evidence concerning the Iceman's broad-based diet is reviewed and the significance of the colon contents for matters other than assessment of food intake is outlined

Cosmic Ray Physics with the LOFAR Radio Telescope

The LOFAR radio telescope is able to measure the radio emission from cosmic ray induced air showers with hundreds of individual antennas. This allows for precision testing of the emission mechanisms for the radio signal as well as determination of the depth of shower maximum $X_{\max}$, the shower observable most sensitive to the mass of the primary cosmic ray, to better than 20 g/cm$^2$. With a densely instrumented circular area of roughly 320 m$^2$, LOFAR is targeting for cosmic ray astrophysics in the energy range $10^{16}$ - $10^{18}$ eV. In this contribution we give an overview of the status, recent results, and future plans of cosmic ray detection with the LOFAR radio telescope.Comment: Proceedings of the 26th Extended European Cosmic Ray Symposium (ECRS), Barnaul/Belokurikha, 201

Calibration of the LOFAR low-band antennas using the Galaxy and a model of the signal chain

The LOw-Frequency ARray (LOFAR) is used to make precise measurements of radio emission from extensive air showers, yielding information about the primary cosmic ray. Interpreting the measured data requires an absolute and frequency-dependent calibration of the LOFAR system response. This is particularly important for spectral analyses, because the shape of the detected signal holds information about the shower development. We revisit the calibration of the LOFAR antennas in the range of 30 - 80 MHz. Using the Galactic emission and a detailed model of the LOFAR signal chain, we find an improved calibration that provides an absolute energy scale and allows for the study of frequency-dependent features in measured signals. With the new calibration, systematic uncertainties of 13% are reached, and comparisons of the spectral shape of calibrated data with simulations show promising agreement.Comment: 23 pages, 10 figure

Affective resonance in response to others' emotional faces varies with affective ratings and psychopathic traits in amygdala and anterior insula

Despite extensive research on the neural basis of empathic responses for pain and disgust, there is limited data about the brain regions that underpin affective response to other people's emotional facial expressions. Here, we addressed this question using event-related functional magnetic resonance imaging to assess neural responses to emotional faces, combined with online ratings of subjective state. When instructed to rate their own affective response to others' faces, participants recruited anterior insula, dorsal anterior cingulate, inferior frontal gyrus, and amygdala, regions consistently implicated in studies investigating empathy for disgust and pain, as well as emotional saliency. Importantly, responses in anterior insula and amygdala were modulated by trial-by-trial variations in subjective affective responses to the emotional facial stimuli. Furthermore, overall task-elicited activations in these regions were negatively associated with psychopathic personality traits, which are characterized by low affective empathy. Our findings suggest that anterior insula and amygdala play important roles in the generation of affective internal states in response to others' emotional cues and that attenuated function in these regions may underlie reduced empathy in individuals with high levels of psychopathic traits.This work was supported by the Portuguese Foundation for Science and Technology (Fundação para a Ciencia e Tecnologia) under grant number [SFRH/BD/60279/2009] awarded to A.S.C.; the Economic and Social Research Council under grant number [RES-062-23-2202] award to E.V; E.V. is a Royal Society Wolfson Research Merit Award holder; C.L.S. was partially supported during the writing of this article by an Economic and Social Research Council award [ES/K008951/1]; J.P.R. is funded by the Wellcome Trust

‘O sibling, where art thou?’ – a review of avian sibling recognition with respect to the mammalian literature

Avian literature on sibling recognition is rare compared to that developed by mammalian researchers. We compare avian and mammalian research on sibling recognition to identify why avian work is rare, how approaches differ and what avian and mammalian researchers can learn from each other. Three factors: (1) biological differences between birds and mammals, (2) conceptual biases and (3) practical constraints, appear to influence our current understanding. Avian research focuses on colonial species because sibling recognition is considered adaptive where ‘mixing potential’ of dependent young is high; research on a wider range of species, breeding systems and ecological conditions is now needed. Studies of acoustic recognition cues dominate avian literature; other types of cues (e.g. visual, olfactory) deserve further attention. The effect of gender on avian sibling recognition has yet to be investigated; mammalian work shows that gender can have important influences. Most importantly, many researchers assume that birds recognise siblings through ‘direct familiarisation’ (commonly known as associative learning or familiarity); future experiments should also incorporate tests for ‘indirect familiarisation’ (commonly known as phenotype matching). If direct familiarisation proves crucial, avian research should investigate how periods of separation influence sibling discrimination. Mammalian researchers typically interpret sibling recognition in broad functional terms (nepotism, optimal outbreeding); some avian researchers more successfully identify specific and testable adaptive explanations, with greater relevance to natural contexts. We end by reporting exciting discoveries from recent studies of avian sibling recognition that inspire further interest in this topic