3,350 research outputs found
Multispectral mapping of the lunar surface using groundbased telescopes
Images of the lunar surface were obtained at several wavelengths using a silicon vidicon imaging system and groundbased telescopes. These images were recorded and processed in digital form so that quantitative information is preserved. The photometric precision of the images is shown to be better than 1 percent. Ratio images calculated by dividing images obtained at two wavelengths (0.40/0.56 micrometer) and 0.95/0.56 micrometer are presented for about 50 percent of the lunar frontside. Spatial resolution is about 2 km at the sub-earth point. A complex of distinct units is evident in the images. Earlier work with the reflectance spectrum of lunar materials indicates that for the most part these units are compositionally distinct. Digital images of this precision are extremely useful to lunar geologists in disentangling the history of the lunar surface
Combatting electoral traces: the Dutch tempest discussion and beyond
In the Dutch e-voting debate, the crucial issue leading to the abandonment of all electronic voting machines was compromising radiation, or tempest. Other countries, however, do not seem to be bothered by this risk. In this paper, we use actor-network theory to analyse the socio-technical origins of the Dutch tempest issue in e-voting, and its consequences for e-voting beyond the Netherlands. We introduce the term electoral traces to denote any physical, digital or social evidence of a voter's choices in an election. From this perspective, we provide guidelines for risk analysis as well as an overview of countermeasures
Neuroprotection in Parkinson's Disease: A Systematic Review of the Preclinical Data.
Aim: This study aimed to systematically review the preclinical data of neuroprotective agents for Parkinson's disease (PD) to support the translation of these compounds. Methods: The study consisted of two phases. In phase I, Pubmed and Scopus were systematically searched for neuroprotective agents for PD. In phase II, a systematic search was conducted for each substance identified in phase I. Articles were included if they used MPTP, 6-OHDA, rotenone or paraquat injury models. Results: Phase I led to the identification of 168 putative neuroprotective agents. Eventually ten compounds were included: melatonin, estrogen, nicotine, caffeine, riluzole, curcumin, coenzyme Q10, aspirin, EGCG and resveratrol. Phase II revealed 113 experimental studies and three reviews. Conclusion: This study clearly depicts the preclinical data of ten promising neuroprotective agents. While some of these compounds have already been tested in clinical use, none of them was studied in an appropriately designed trial to determine a neuroprotective effect. In expectation of qualitatively improved neuroprotection trials, the data from this study provide a firm foundation for future research. © Douna et al
Preliminary results of spectral reflectance studies of tycho crater
The preliminary analysis and interpretation of near infrared spectra obtained for both the interior and exterior deposits associated with the Tycho crater is presented. Specific objectives were: (1) to determine the composition and stratigraphy of the highland crust in the Tycho target site; (2) to determine the likely composition of the primary ejecta which may be present in ray deposits; (3) to investigate the nature of spectral units defined in previous studies; (4) to further investigate the nature and origin of both the bright and dark haloes around the rim crest; and (5) to compare the compositions determined for the Tycho units with those of the Aristarchus crater as well as typical highland deposits. The spectra obtained for the interior areas exhibit similar spectral features. These include relatively strong 1 micron absorption bands whose minima are centered between 0.97 and 0.99 microns and shallow to intermediate continuum slopes. The spectra generally exhibit indications of a 1.3 micron feature consistent with the presence of Fe(2+) bearing plagioclase feldspar. The strong 1 micron absorption features indicate a dominant high Ca clinopyroxene component. Results obtained from the ejecta deposits show that the spectrum of the inner, bright halo is almost identical with those obtained for interior units. The spectrum of the dark halo exhibits a wide, relatively shallow absorption feature centered at 1.01 microns, a 1.3 micron absorption, and a steep continuum slope. This spectrum is interpreted as indicating the presence of pyroxene, Fe-bearing feldspar, and a significant component of Fe-bearing impact melt glass. Finally, the spectra of spots inside Tycho show similarity with certain spectra for Aristarchus. However, the suite of spectra obtained for Tycho exhibits a different trend in terms of band center versus width
In de achtertuin van het Carons Hofke: archeologisch onderzoek te Merksplas, Carons Hofke
Dit rapport werd ingediend bij het agentschap samen met een aantal afzonderlijke digitale bijlagen. Een aantal van deze bijlagen zijn niet inbegrepen in dit pdf document en zijn niet online beschikbaar. Sommige bijlagen (grondplannen, fotos, spoorbeschrijvingen, enz.) kunnen van belang zijn voor een betere lezing en interpretatie van dit rapport. Indien u deze bijlagen wenst te raadplegen kan u daarvoor contact opnemen met: [email protected]
Natural supramolecular protein assemblies
Supramolecular protein assemblies are an emerging area within the chemical sciences, which combine the topological structures of the field of supramolecular chemistry and the state-of-the-art chemical biology approaches to unravel the formation and function of protein assemblies. Recent chemical and biological studies on natural multimeric protein structures, including fibers, rings, tubes, catenanes, knots, and cages, have shown that the quaternary structures of proteins are a prerequisite for their highly specific biological functions. In this review, we illustrate that a striking structural diversity of protein assemblies is present in nature. Furthermore, we describe structure–function relationship studies for selected classes of protein architectures, and we highlight the techniques that enable the characterisation of supramolecular protein structures
Understanding How Components of Organisations Contribute to Attacks
Attacks on organisations today explore many different layers, including buildings infrastructure, IT infrastructure, and human factor – the physical, virtual, and social layer. Identifying possible attacks, understanding their impact, and attributing their origin and contributing factors is difficult. Recently, system models have been used for automatically identifying possible attacks on the modelled organisation. The generated attacks consider all three layers, making the contribution of building infrastructure, computer infrastructure, and humans (insiders and outsiders) explicit. However, this contribution is only visible in the attack trees as part of the performed steps; it cannot be mapped back to the model directly since the actions usually involve several elements (attacker and targeted actor or asset). Especially for large attack trees, understanding the relations between several model components quickly results in a large quantity of interrelations, which are hard to grasp. In this work we present several approaches for visualising attributes of attacks such as likelihood of success, impact, and required time or skill level. The resulting visualisations provide a link between attacks on an organisations and the contribution of parts of an organisation to the attack and its impact
- …