The microwave spectrum of solar millisecond spikes

The microwave radiation from solar flares sometimes shows short and intensive spikes which are superimposed on the burst continuum. In order to determine the upper frequency limit of their occurrence and the circular polarization, a statistical analysis was performed on digital microwave observations from 3.2 to 92.5 GHz. Additionally, fine structures were investigated with a fast 32-channel spectrometer at 3.47 GHz. It was found that about 10 percent of the bursts show fine structures at 3.2 and 5.2 GHz, whereas none occurred above 8.4 GHz. Most of the observed spikes were very short and their bandwidth varied from below 0.5 MHz to more than 200 MHz. Simultaneous observations at two further frequencies showed no coincident spikes at the second and third harmonic. The observations can be explained by the theory of electron cyclotron masering if the observed bandwidths are determined by magnetic field inhomogeneities or if the rise times are independent of the source diameters. The latter would imply source sizes between 50 and 100 km

Script-Based QOS Specifications for Multimedia Presentations

Multimedia presentations can convey information not only by the sequence of events but by their timing. The correctness of such presentations thus depends on the timing of events as well as their sequence and content. This paper introduces a formal specification language for playback of real-time presentations. The main contribution of this language is a quality of service (QOS) specification that relaxes resolution and synchronization requirements for playback. Our definitions give a precise meaning to the correctness of a presentation. This specification language will form the basis for a QOS interface for reservation of operating system resources

Einfluss von Kraftfutterreduzierung auf Milchleistung und Tiergesundheit in einem Schweizerischen Milchviehbetrieb – erste Resultate

Obwohl die Richtlinien der Bio Suisse einen maximalen Anteil an Kraftfutter von 10% je Grossvieheinheit zulassen, wird zur Zeit diskutiert, ob unter den Bedingungen der Schweizerischen Biomilchproduktion ein vollständiger Verzicht auf Kraftfutter und tierphysiologischen Aspekten möglich ist, um eine nachhaltige Tierhaltung konsequent umzusetzen. In einem Schweizer Biomilchbetrieb mit ca. 70 Kühen und 7300 kg Milch / Jahr wurden daher die Kühe per Zufall in 2 Fütterungsgruppen aufgeteilt, wobei Gruppe A (n = 42) als Versuchsgruppe ohne Kraftfutter (schrittweise Kürzung innerhalb der Laktation) und Gruppe B (n=27) gemäss Richtlinien (<10% Kraftfutter) über zunächst ein Jahr gefüttert wurden. Zusätzlich wurde eine Hochleistungsgruppe (C; n=13) beobachtet, die nicht Teil der vergleichenden Analyse war. Sie enthielt Kühe, die nach Angaben der Besitzer oder gemäss vorgängig ausgewerteter Milchleistungs- und Gesundheitsdaten als Risikokühe nicht in die zufällige Auswahl für die beiden Vergleichsgruppen aufgenommen werden sollten. Während eines Jahres wurden die Milchleistung, Körperfettauflage (Body Condition Score; BCS) und Tiergesundheit aufgezeichnet. Kühe der Gruppe A reduzierten die durchschnittliche Milchleistung im Vergleich zum Vorjahr deutlich um 15% im Vergleich zu 1% Reduktion in Gruppe B. Der BCS lag im Mittelwert während Tag 31 bis 100 nach der Geburt etwas höher in der Gruppe A (2,98) im Vergleich zu Gruppe B (2.88). Es wurde kein signifikanter Unterschied zwischen der Anzahl tierärztlicher Diagnosen im Hinblick auf Stoffwechselstörungen und Fruchtbarkeit ermittelt. Insgesamt mussten über ein Jahr 6 Kühe der Gruppe A (14%) musste wieder von Konzentraten gefüttert werden, da entweder der BCS unter 2.5 zu sinken drohte (Abbruchkriterium, das allerdings keine Kuh tatsächlich erreichte; n=4) oder stoffwechselbezogene Therapien durchgeführt wurden, ohne allerdings klinisch erkrankte Tiere zu registrieren (n=2). Diese 6 Tiere und die 13 Kühe, die nicht in die Untersuchung aufgenommen wurden ergeben, dass bei 75% der Kühe der untersuchten Herde eine vollständige Reduktion von Konzentraten durchführbar ist, ohne Tiergesundheitsdepressionen zu provozieren. Allerdings muss eine signifikante Reduktion der Milchleistung in Kauf genommen werden, bei stabilen Milchinhaltsstoffen

Device and Physical Data Independence for Multimedia Presentations

Multimedia computing promises access to any type of visual or aural medium on the desktop. But in this networked future, will every type of media be accessible from every terminal device? Current multimedia standards do not allow content that is authored for high-bandwidth workstations to scale down for low-bandwidth applications. The problem is that application requests are commonly interpreted as requests for the highest possible quality and resource overloads are handled by ad hoc methods. We can begin to solve this problem by specifying Quality of Service (QOS) requirements based on functionality rather than on content encoding and device capabilities

Polariton quantum boxes in semiconductor microcavities

We report on the realization of polariton quantum boxes in a semiconductor microcavity under strong coupling regime. The quantum boxes consist of mesas that confine the cavity photon, etched on top of the spacer of a microcavity. For mesas with sizes of the order of a few micron in width and nm in depth, we observe quantization, caused by the lateral confinement, of the polariton modes in several peaks. We evidence the strong exciton-photon coupling regime through a typical/clear anticrossing curve for each quantized level. Moreover the growth technique is of high quality, which opens the way for the conception of new optoelectronic devices

Buying drugs on a Darknet market: A better deal? Studying the online illicit drug market through the analysis of digital, physical and chemical data.

Darknet markets, also known as cryptomarkets, are websites located on the Darknet and designed to allow the trafficking of illicit products, mainly drugs. This study aims at presenting the added value of combining digital, chemical and physical information to reconstruct sellers' activities. In particular, this research focuses on Evolution, one of the most popular cryptomarkets active from January 2014 to March 2015. Evolution source code files were analysed using Python scripts based on regular expressions to extract information about listings (i.e., sales proposals) and sellers. The results revealed more than 48,000 listings and around 2700 vendors claiming to send illicit drug products from 70 countries. The most frequent categories of illicit drugs offered by vendors were cannabis-related products (around 25%) followed by ecstasy (MDA, MDMA) and stimulants (cocaine, speed). The cryptomarket was then especially studied from a Swiss point of view. Illicit drugs were purchased from three sellers located in Switzerland. The purchases were carried out to confront digital information (e.g., the type of drug, the purity, the shipping country and the concealment methods mentioned on listings) with the physical analysis of the shipment packaging and the chemical analysis of the received product (purity, cutting agents, chemical profile based on minor and major alkaloids, chemical class). The results show that digital information, such as concealment methods and shipping country, seems accurate. But the illicit drugs purity is found to be different from the information indicated on their respective listings. Moreover, chemical profiling highlighted links between cocaine sold online and specimens seized in Western Switzerland. This study highlights that (1) the forensic analysis of the received products allows the evaluation of the accuracy of digital data collected on the website, and (2) the information from digital and physical/chemical traces are complementary to evaluate the practices of the online selling of illicit drugs on cryptomarkets

A geographical analysis of trafficking on a popular darknet market

© 2017 Elsevier B.V. Cryptomarkets are online marketplaces, located on the darknet, that facilitate the trading of a variety of illegal goods, mostly drugs. While the literature essentially focus on drugs, various other goods and products related to financial or identity fraud, firearms, counterfeit goods, as well as doping products are also offered on these marketplaces. Through the analysis of relevant data collected on a popular marketplace in 2014–2015, Evolution, this research provides an analysis of the structure of trafficking (types and proportions of products, number of vendors and shipping countries). It also aims at highlighting geographical patterns in the trafficking of these products (e.g. trafficking flows, specialisation of vendors and assessment of their role in the distribution chain). The analysis of the flow of goods between countries emphasises the role of specific countries in the international and domestic trafficking, potentially informing law enforcement agencies to target domestic mails or international posts from specific countries. The research also highlights the large proportion of licit and illicit drug listings and vendors on Evolution, followed by various fraud issues (in particular, financial fraud), the sharing of knowledge (tutorials) and finally goods, currencies and precious metals (principally luxury goods). Looking at the shipping country, there seems to be a clear division between digital and physical products, with more specific information for physical goods. This reveals that the spatial analysis of trafficking is particularly meaningful in the case of physical products (such as illicit drugs) and to a lesser extent for digital products. Finally, the geographical analysis reveals that spatial patterns on Evolution tend to reflect the structure of the traditional illicit market. However, regarding illicit drugs, country-specificity has been observed and are presented in this article

Résistances aux vermifuges et gestion durable des parasites des pâturages

La lutte contre les parasites chez les bovins prend un nouveau tournant et n’est plus uniquement résolue par l’application de vermifuge. Dès qu’une résistance existe, il faut à tout prix endiguer sa progression. Le bovin développe une immunité durable contre les strongles gastro-intestinaux : profitons-en ! Au vu des résultats suisses concernant la résistance aux vermifuges, les plans de maitrise de l’infestation par les parasites des pâturages doivent être conçus pour prévenir l’impact sanitaire et économique. Or, ces plans doivent absolument tenir compte des conséquences à plus long terme de l’usage des traitements anthelminthiques : développement des résistances, résidus, impacts sur la biodiversité

Repenser la gestion et l’impact des parasites internes chez les bovins

Certains vermifuges ont un impact très néfaste sur les insectes coprophages. Il est donc essentiel d’intégrer la gestion des parasites internes du bovin et le soin à la terre dans ses pratiques