Since 2010, the “Aquila” company is offering GPS/GSM dataloggers. It started with 35 g units, that were further developed into 22 g devices. Already then, the goal was to withstand the harshest ...possible conditions – especially during European winter. Simultaneously the GSM technology provided more economic form of tracking compared to satellite devices. These two goals had been achieved and together with competitive performance features – like fix every 3 minutes (with possibility of direct dispatch to the server) – plus innovative and user-friendly data portal, have helped researching and conserving birds in many parts of the world, as well as have proved to be a reliable and outstanding product on the market. Now, after 13 years, it is time for new models and new technologies. With 9 g devices and internet transmission begins a new era…
Delivering information on bird movement is the main reason for utilization of dataloggers in research. It was, however, very soon discovered, that information regarding mortality factors can ...sometimes be of higher conservation value. Since 2011, the “Aquila” company is offering GPS/GSM dataloggers. Today an attempt is made to measure the efficiency of Aquila dataloggers in delivering solid data regarding bird mortality rate. Analysed were 111 devices used in Eastern Europe and Asia within 7 scientific projects from 2017 to 2021. The results show that over 67% of the devices are either still operational or were collected providing evidence of the bird mortality problems. Of the remaining 33%, further probable mortality issues could be withdrawn from the delivered data, despite lacking clear evidence, for half of the cases. In total, fate of 18% of the tagged birds remains unknown.
Single-Cycle Nonlinear Optics Goulielmakis, E; Schultze, M; Hofstetter, M ...
Science (American Association for the Advancement of Science),
06/2008, Letnik:
320, Številka:
5883
Journal Article
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Nonlinear optics plays a central role in the advancement of optical science and laser-based technologies. We report on the confinement of the nonlinear interaction of light with matter to a single ...wave cycle and demonstrate its utility for time-resolved and strong-field science. The electric field of 3.3-femtosecond, 0.72-micron laser pulses with a controlled and measured waveform ionizes atoms near the crests of the central wave cycle, with ionization being virtually switched off outside this interval. Isolated sub-100-attosecond pulses of extreme ultraviolet light (photon energy ~ 80 electron volts), containing ~0.5 nanojoule of energy, emerge from the interaction with a conversion efficiency of ~10⁻⁶. These tools enable the study of the precision control of electron motion with light fields and electron-electron interactions with a resolution approaching the atomic unit of time (~24 attoseconds).
This article explores the place of music in the classical liberal arts curriculum, which consists of the trivium (the arts of language) and the quadrivium (the arts of number). Music is part of the ...quadrivial disciplines and studied as applied arithmetic. However, as argued in this article, it is also a bridge to the discipline of rhetoric, which is part of the trivium. The article begins with a brief review of St. Augustine’s De Musica, the first in a planned (but unrealized) series of dialogs on the value of the classical liberal arts to the emerging Christian culture of Antiquity. It proceeds to a discussion of music and its relation to the contemporary American liberal arts curriculum. Two case studies follow that address the ontological reality of music as a time-bound medium, and attempts to mute this reality in the service of creating a sense of timelessness. Thus subsuming the temporal into the Divine–what Augustine called “a poem of the universe”. The first case study is Dante Alighieri’s Paradiso, which is a journey through the heavens with each planet representing one of the seven liberal arts as preparatory to the Beatific Vision. The second case study focuses on J.S. Bach’s attempts to create a sense of timelessness in the St. Matthew Passion by the use of musical forms and musical rhetorical devices that tend to abolish time. The article concludes with suggestions on how teachers can use 20th and 21st-century movements in Western art music as pathways to appreciate music’s pivotal role in the Catholic liberal arts tradition.
Sleeping sickness is a fatal disease caused by the protozoan parasite Trypanosoma brucei (Tb). Inosine-5'-monophosphate dehydrogenase (IMPDH) has been proposed as a potential drug target, since it ...maintains the balance between guanylate deoxynucleotide and ribonucleotide levels that is pivotal for the parasite. Here we report the structure of TbIMPDH at room temperature utilizing free-electron laser radiation on crystals grown in living insect cells. The 2.80 Å resolution structure reveals the presence of ATP and GMP at the canonical sites of the Bateman domains, the latter in a so far unknown coordination mode. Consistent with previously reported IMPDH complexes harboring guanosine nucleotides at the second canonical site, TbIMPDH forms a compact oligomer structure, supporting a nucleotide-controlled conformational switch that allosterically modulates the catalytic activity. The oligomeric TbIMPDH structure we present here reveals the potential of in cellulo crystallization to identify genuine allosteric co-factors from a natural reservoir of specific compounds.
Intense femtosecond x-ray pulses from free-electron laser sources allow the imaging of individual particles in a single shot. Early experiments at the Linac Coherent Light Source (LCLS) have led to ...rapid progress in the field and, so far, coherent diffractive images have been recorded from biological specimens, aerosols, and quantum systems with a few-tens-of-nanometers resolution. In March 2014, LCLS held a workshop to discuss the scientific and technical challenges for reaching the ultimate goal of atomic resolution with single-shot coherent diffractive imaging. This paper summarizes the workshop findings and presents the roadmap toward reaching atomic resolution, 3D imaging at free-electron laser sources.
Abstract
X-ray free-electron lasers can generate radiation pulses with extreme peak intensities at short wavelengths. This enables the investigation of laser–matter interactions in a regime of high ...fields, yet at a non-relativistic ponderomotive potential, where ordinary rules of light–matter interaction may no longer apply and nonlinear processes are starting to become observable. Despite small cross-sections, first nonlinear effects in the hard x-ray regime have recently been observed in solid targets, including x-ray-optical sum-frequency generation (XSFG), x-ray second harmonic generation (XSHG) and two-photon Compton scattering (2PCS). Nonlinear interactions of bound electrons in the x-ray range are fundamentally different from those dominating at optical frequencies. Whereas in the optical regime nonlinearities are predominantly caused by anharmonicities of the atomic potential in the chemical bonds, x-ray nonlinearities far above atomic resonances are expected to be due to nonlinear oscillations of quasi-free electrons, including inner-shell atomic electrons. While the quasi-free-electron model agrees reasonably well with the experimental data for XSFG and XSHG, 2PCS measurements have led to unexpected results: the energy of the nonlinearly scattered photons from non-relativistic electrons shows a substantial unexpected red shift in addition to the Compton shift that is well beyond that predicted by a nonlinear quantum electrodynamics model for free electrons.
A potential explanation for the spectral broadening is based on a previously unexplored scattering process that involves the whole atom rather than just quasi-free electrons. A first simulation that includes the atomic binding potential was successful in describing a broadening of the spectrum of the nonlinearly scattered photons to longer wavelengths for soft x-rays. However, the same model does not show any broadening at hard x-ray wavelengths, which is in agreement with other simulation approaches. To this point no calculation has been able to reproduce the experimentally observed broadening.
Here we present further experimental data of 2PCS for an extended parameter range using additional diagnostics. In particular, we present measurements of the electron momentum distribution during the interaction that strongly suggest that the spectral broadening is not caused by an increased plasma temperature. We extend our measurement of the magnitude of the red shift in beryllium to
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in addition to the Compton shift expected for free electrons and expand the measurement of the angular distribution to include forward scattering angles. We also present first measurements of 2PCS from diamond.
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