Speculations on Isolated Lepton Events at HERA

Speculations on mechanisms which might be responsible for events with an isolated high p_T lepton, a hadron jet and missing energy, as observed in the H1 experiment at HERA, are discussed.Comment: LaTeX, 6 pages, 2 figures, presented at the XXXI Conference of Theoretical Physics "Matter to the Deepest", Ustron, Poland, September 5-11, 200

Mode-switching: a new technique for electronically varying the agglomeration position in an acoustic particle manipulator

Acoustic radiation forces offer a means of manipulating particles within a fluid. Much interest in recent years has focussed on the use of radiation forces in microfluidic (or “lab on a chip”) devices. Such devices are well matched to the use of ultrasonic standing waves in which the resonant dimensions of the chamber are smaller than the ultrasonic wavelength in use. However, such devices have typically been limited to moving particles to one or two predetermined planes, whose positions are determined by acoustic pressure nodes/anti-nodes set up in the ultrasonic standing wave. In most cases devices have been designed to move particles to either the centre or (more recently) the side of a flow channel using ultrasonic frequencies that produce a half or quarter wavelength over the channel, respectively.It is demonstrated here that by rapidly switching back and forth between half and quarter wavelength frequencies – mode-switching – a new agglomeration position is established that permits beads to be brought to any arbitrary point between the half and quarter-wave nodes. This new agglomeration position is effectively a position of stable equilibrium. This has many potential applications, particularly in cell sorting and manipulation. It should also enable precise control of agglomeration position to be maintained regardless of manufacturing tolerances, temperature variations, fluid medium characteristics and particle concentration

The stratigraphy and structure of the Faroese continental margin

This paper presents a summary of the stratigraphy and structure of the Faroese region. As the Faroese area is mostly covered by volcanic material, the nature of the pre-volcanic geology remains largely unproven. Seismic refraction data provide some indications of the distribution of crystalline basement, which probably comprises Archaean rocks, with the overlying cover composed predominantly of Upper Mesozoic (Cretaceous?) and Cenozoic strata. The Cenozoic succession is dominated by the syn-break-up Faroe Islands Basalt Group, which crops out on the Faroe Islands (where it is up to 6.6 km thick) and shelf areas; post-break-up sediments are preserved in the adjacent deep-water basins, including the Faroe–Shetland Basin. Seismic interpretation of the post-volcanic strata shows that almost every sub-basin in the Faroe–Shetland Basin has been affected by structural inversion, particularly during the Miocene. These effects are also observed on the Faroe Platform, the Munkagrunnur Ridge and the Fugloy Ridge, where interpretation of low-gravity anomalies suggests a large-scale fold pattern. The structure of the Iceland–Faroe Ridge, which borders the NW part of the Faroe area, remains ambiguous. The generally thick crust, together with the absence of well-defined seawards-dipping reflectors, may indicate that much of it is underlain by continental material

Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans

The Greenland and Antarctic Ice Sheets cover ~\n10% of global land surface, but are rarely considered as active components of the global iron cycle. The ocean waters around both ice sheets harbour highly productive coastal ecosystems, many of which are iron limited. Measurements of iron concentrations in subglacial runoff from a large Greenland Ice Sheet catchment reveal the potential for globally significant export of labile iron fractions to the near-coastal euphotic zone. We estimate that the flux of bioavailable iron associated with glacial runoff is 0.40–2.54?Tg per year in Greenland and 0.06–0.17?Tg per year in Antarctica. Iron fluxes are dominated by a highly reactive and potentially bioavailable nanoparticulate suspended sediment fraction, similar to that identified in Antarctic icebergs. Estimates of labile iron fluxes in meltwater are comparable with aeolian dust fluxes to the oceans surrounding Greenland and Antarctica, and are similarly expected to increase in a warming climate with enhanced melting

Does Worksharing Work? Some Empirical Evidence from the IAB Panel

Recent policy debate in Europe suggests that a shorter workweek will lead to more jobs (worksharing). We derive and estimate a model where the firm employs two types of worker, some working overtime, the rest standard hours. Worksharing is not always a prediction of the theory. Using German establishment-level panel data (the IAB panel), 1993-1999, we find pro-worksharing effects in small plants in the East German non-service sector. There is evidence that a cut in standard hours lowers the proportion of overtime workers in a plant, as predicted by the theory, and increases the proportion of standard-time plants.In der wirtschaftspolitischen Debatte werden immer wieder Ver- kürzungen der wöchentlichen Normalarbeitszeit zur Bekämpfung der Arbeitslosigkeit gefordert. Wir präsentieren in dem vorliegenden Papier ein Arbeitsnachfragemodell, das zwischen Beschäftigten mit und ohne Überstunden unterscheidet. Der Effekt einer Arbeitszeitverkürzung auf die Beschäftigung kann dabei nicht eindeutig beantwortet werden. Auf der Basis des IAB-Betriebspanels, 1993-1999, finden wir, dass in kleinen Betrieben des Produzierenden Gewerbes Ostdeutschlands Arbeitszeitverkürzungen und Beschäftigungserhöhungen miteinander einhergingen. Au?erdem zeigt sich, dass eine Verkürzung der wöchentlichen Arbeitszeit den Anteil der Überstundenbeschäftigten - so wie von der Theorie vorhergesagt - senkt und den Anteil der Betriebe ohne Überstunden erhöht