Organisational controls, typologies and time scales of paraglacial gravel-dominated coastal systems

The fundamental controls on the initiation and development of gravel-dominated deposits (beaches and barriers) on paraglacial coasts are particle size and shape, sediment supply, storm wave activity (primarily runup), relative sea-level (RSL) change, and terrestrial basement structure (primarily as it affects accommodation space). This paper examines the stochastic basis for barrier organisation as shown by variation in gravel barrier architecture. We recognise punctuated self-organisation of barrier development that is disrupted by short phases of barrier instability. The latter results from positive feedback causing barrier breakdown when sediment supply is exhausted. We examine published typologies for gravel barriers and advocate a consolidated perspective using rate of RSL change and sediment supply. We also consider the temporal variation in controls on barrier development. These are examined in terms of a simple behavioural model (BARCH) for prograding gravel barrier architecture and its sensitivity to such controls. The nature of macroscale (102–103 years) gravel barrier development, including inherited characteristics that influence barrier genesis, as well as forcing from changing RSL, sediment supply, headland control and barrier inertia, is examined in the context of long-surviving barriers along the southern England coastline.

Observational evidence of gentle chromospheric evaporation during the impulsive phase of a solar flare

Observational evidence of gentle chromospheric evaporation during the impulsive phase of a C9.1 solar flare is presented using data from the Reuven Ramaty High-Energy Solar Spectroscopic Imager and the Coronal Diagnostic Spectrometer on board the Solar and Heliospheric Observatory. Until now, evidence of gentle evaporation has often been reported during the decay phase of solar flares, where thermal conduction is thought to be the driving mechanism. Here we show that the chromospheric response to a low flux of nonthermal electrons (>= 5 cm(-2) s(-1)) results in plasma upflows of 13 +/- 16, 16 +/- 18, and 110 +/- 58 km s(-1) in the cool He I and O V emission lines and the 8 MK Fe XIX line, respectively. These findings, in conjunction with other recently reported work, now confirm that the dynamic response of the solar atmosphere is sensitively dependent on the flux of incident electrons.

Aggression after traumatic brain injury: Analysing socially desirable responses and the nature of aggressive traits.

Primary objective: To compare patients with traumatic brain injury (TBI) with controls on sub-types of aggression and explore the role of social desirability.
Design: Quasi-experimental, matched-participants design.
Methods and procedures: Sixty-nine participants were included in the study. The sample comprised a TBI group (n = 24), a spinal cord injury (SCI) group (n = 21) and an uninjured (UI) group of matched healthy volunteers (n = 24). Participants were given self-report measures of aggression, social desirability and impulsivity. Sixty-one independent ‘other-raters’ were nominated, who rated participant pre-morbid and post-morbid aggression.
Main outcomes and results: Using standardized norms, 25–39% of participants with TBI were classified as high average–very high on anger and 35–38% as high average–very high on verbal aggression. Other-raters rated participants with TBI as significantly higher on verbal aggression than SCI and UI participants. There were no differences between the groups on physical aggression. The TBI group also had higher levels of impulsivity than SCI and UI groups. Social desirability was a highly significant predictor of self-reported aggression for the entire sample.
Conclusions: Impulsive verbal aggression and anger are the principal aggressive traits after brain injury. Physical aggression may present in extreme cases after TBI, but appears less prominent overall in this population. Social desirability, previously overlooked in research examining TBI aggression, emerged as an influential variable that should be considered in future TBI research.

Impulsive electric fields driven by high-intensity interactions

The interaction of high-intensity laser pulses with matter releases instantaneously ultra-large currents of highly energetic electrons, leading to the generation of highly-transient, large-amplitude electric and magnetic fields. We report results of recent experiments in which such charge dynamics have been studied by using proton probing techniques able to provide maps of the electrostatic fields with high spatial and temporal resolution. The dynamics of ponderomotive channeling in underdense plasmas have been studied in this way, as also the processes of Debye sheath formation and MeV ion front expansion at the rear of laser-irradiated thin metallic foils. Laser-driven impulsive fields at the surface of solid targets can be applied for energy-selective ion beam focusing.

A complex zinc finger controls the enzymatic activities of nidovirus helicases.

Nidoviruses (Coronaviridae, Arteriviridae, and Roniviridae) encode a nonstructural protein, called nsp10 in arteriviruses and nsp13 in coronaviruses, that is comprised of a C-terminal superfamily 1 helicase domain and an N-terminal, putative zinc-binding domain (ZBD). Previously, mutations in the equine arteritis virus (EAV) nsp10 ZBD were shown to block arterivirus reproduction by disrupting RNA synthesis and possibly virion biogenesis. Here, we characterized the ATPase and helicase activities of bacterially expressed mutant forms of nsp10 and its human coronavirus 229E ortholog, nsp13, and correlated these in vitro activities with specific virus phenotypes. Replacement of conserved Cys or His residues with Ala proved to be more deleterious than Cys-for-His or His-for-Cys replacements. Furthermore, denaturation-renaturation experiments revealed that, during protein refolding, Zn2+ is essential for the rescue of the enzymatic activities of nidovirus helicases. Taken together, the data strongly support the zinc-binding function of the N-terminal domain of nidovirus helicases. nsp10 ATPase/helicase deficiency resulting from single-residue substitutions in the ZBD or deletion of the entire domain could not be complemented in trans by wild-type ZBD, suggesting a critical function of the ZBD in cis. Consistently, no viral RNA synthesis was detected after transfection of EAV full-length RNAs encoding ATPase/helicase-deficient nsp10 into susceptible cells. In contrast, diverse phenotypes were observed for mutants with enzymatically active nsp10, which in a number of cases correlated with the activities measured in vitro. Collectively, our data suggest that the ZBD is critically involved in nidovirus replication and transcription by modulating the enzymatic activities of the helicase domain and other, yet unknown, mechanisms.