Radiocarbon calibration in the Anglo-Saxon period: AD 495-725

Radiocarbon dating has been rarely used for chronological problems relating to the Anglo-Saxon period. The "flatness" of the calibration curve and the resultant wide range in calendrical dates provide little advantage over traditional archaeological dating in this period. Recent advances in Bayesian methodology have, however, created the possibility of refining and checking the established chronologies, based on typology of artifacts, against 14C dates. The calibration process, within such a confined age range, however, relies heavily on the structural accuracy of the calibration curve. We have therefore re-measured, at decadal intervals, a section of the Irish oak chronology for the period AD 495–725. These measurements have been included in IntCal04.

PVT Property Measurements for Some Aliphatic Esters from (298 to 393) K and up to 35 MPa

The results of PVT measurements of the liquid phase within the temperature range of (298 to 393) K and up to 35 MPa are presented for some aliphatic esters. Measurements were made by means of a vibrating-tube densimeter, model DMA 512P from Anton Parr. The calibration of the densimeter was performed with water and n-heptane as reference fluids. The experimental PVT data have been correlated by a Tait equation. This equation gives excellent results when used to predict the density of the esters using the method proposed by Thomson et al. (AIChE J. 1982, 28, 671-676). Isothermal compressibilities, isobaric expansivities, thermal pressure coefficients, and changes in the isobaric heat capacity have been calculated from the volumetric data.

Impairments of hippocampal synaptic plasticity induced by aggregated beta-amyloid (25-35) are dependent on stimulation-protocol and genetic background

The aggregation of beta-amyloid to plaques in the brain is one of the hallmarks of Alzheimer disease (AD). Numerous studies have tried to elucidate to what degree amyloid peptides play a role in the neurodegenerative developments seen in AD. While most studies report an effect of amyloid on neural activity and cognitive abilities of rodents, there have been many inconsistencies in the results. This study investigated to what degree the different genetic backgrounds affect the outcome of beta-amyloid fragment (25-35) on synaptic plasticity in vivo in the rat hippocampus. Two strains, Wistar and Lister hooded rats, were tested. In addition, the effects of a strong (600 stimuli) and a weak stimulation protocol (100 stimuli) on impairments of LTP were analysed. Furthermore, since the state of amyloid aggregation appears to play a role in the induction of toxic processes, it was tested by dual polarisation interferometry to what degree and at what speed beta-amyloid (25-35) can aggregate in vitro. It was found that 100 nmol beta-amyloid (25-35) injected icv did impair LTP in Wistar rats when using the weak but not the strong stimulation protocol (P <0.001). One-hundred nano mole of the reverse sequence amyloid (35-25) had no effect. LTP in Lister Hooded rats was not impaired by amyloid at any stimulation protocol. The aggregation studies showed that amyloid (25-35) aggregated within hours, while amyloid (35-25) did not. These results show that the genetic background and the stimulation protocol are important variables that greatly influence the experimental outcome. The fact that amyloid (25-35) aggregated quickly and showed neurophysiological effects, while amyloid (35-25) did not aggregate and did not show any effects indicates that the state of aggregation plays an important role in the physiological effects.

Production of ultracollimated bunches of multi-MeV electrons by 35 fs laser pulses propagating in exploding-foil plasmas

Very collimated bunches of high energy electrons have been produced by focusing super-intense femtosecond laser pulses in submillimeter under-dense plasmas. The density of the plasma, preformed with the laser exploding-foil technique, was mapped using Nomarski interferometry. The electron beam was fully characterized: up to 10(9) electrons per shot were accelerated, most of which in a beam of aperture below 10(-3) sterad, with energies up to 40 MeV. These measurements, which are well modeled by three-dimensional numerical simulations, validate a reliable method to generate ultrashort and ultracollimated electron bunches. (C) 2002 American Institute of Physics.

Ultrafast low-loss 42-70 GHz differential SPDT switch in 0.35 μm SiGe technology

This paper presents an ultrafast wideband low-loss single-pole double-throw (SPDT) differential switch in 0.35 µ m SiGe bipolar technology. The proposed topology adopting current-steering technique results in a total measured switching time of 75 ps , which suggests a maximum switching rate of 13 Gb/s, the fastest ever reported at V-band. In addition, the switch exhibits an insertion loss lower than 1.25 dB and an isolation higher than 18 dB from 42 GHz to 70 GHz. © 2006 IEEE.

40-70 GHz 13 Gbps 1-dB loss SPST and SPDT differential switches in 0.35 μm SiGe technology

This paper presents the design and characterization of ultrafast wideband low-loss single-pole single-throw (SPST) and single-pole double-throw (SPDT) differential switches. The SPDT switch exhibits insertion loss of lower than 1.25 dB from 42 to 70 GHz and isolation of better than 20 dB from 40 to 65 GHz. Similar low-loss and broadband characteristics are also observed from the measured SPST switch. The proposed switch topologies adopting current-steering technique and implemented in 0.35 µm SiGe bipolar technology result in a switching time of only 75 ps. This suggests a maximum switching speed of 13 Gbps, the fastest ever reported at V-band.

Cultures of Rioting and Anti-Systemic Politics in Southern Europe

The article investigates why, despite similar background conditions, Greece has been the site of frequent, highly visible, fringe, anti-system politics and street riots, while similar phenomena are rare in Spain. Although the article's focal point is the eruption of the December 2008 riots in Athens, it sheds light on the two countries' diverse social reactions to the sovereign debt crisis. Deploying the tool of media framing, it argues that historical legacies and political cultures matter. In the Greek case, the transition to democracy shaped a political ‘culture of sympathy’ towards acts of resistance to the state, a culture that has been institutionalised since the mid-1970s.

Switchable radar cross-section evanescent waveguide antenna affiliation

We present a simple method of forming a switchable radar cross-section (RCS) in evanescent waveguide.Here, the antenna can be selected to be matched to free space, or to act as an almost perfect reflector of incident energy via a single SPST switch located at the antenna aperture. With the aperture switch open, the antenna is matched over a measured bandwidth of 17.5%, from 2.35 to 2.8 GHz, for reflection coefficient <-10 dB, in 2.725 GHz cutoff waveguide. With the aperture switch closed, a minimum reflection coefficient of -2.5 dB across the bandwidth is observed, proving that the antenna has the capacity to be made RCS reconfigurable. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1849–1851, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26981

Carrefours de la sociocritique. E´ dite´ par ANTHONY GLINOER. (¼ Texte: revue de critique et de the´orie litte´raire, 45/46). Toronto: E´ ditions Trintexte, 2009. 227 pp. Pb CAD $35.00

French Studies (2012) 66 (1): 125-126 doi:10.1093/fs/knr208