Habenula-prefrontal resting-state connectivity in reactive aggressive men - A pilot study.

Disproportionate anger and reactive aggression in response to provocation are core symptoms of intermittent-explosive disorder (IED). Previous research shows a link between the propensity for aggression in healthy individuals and altered functioning of prefrontal-limbic and default-mode networks (DMN) at rest when no provocation is present. In a pilot study, we used resting-state functional magnetic resonance imaging to investigate the effects of pronounced reactive aggression in men, exemplified by IED, on the functional organization of resting-state brain networks including subcortical nodes such as the habenula previously implicated in aggression in preclinical models. Graph theory was applied to resting-state networks to determine alterations in global efficiency and clustering in high reactive aggressive men compared to low reactive aggressive men (controls). Further, we computed within-group correlations between trait aggression and graph measures, as well as within-group whole-brain seed-to-voxel regression analyses between trait aggression and habenula resting-state functional connectivity (rsFC). Reactive aggressive men compared to controls showed higher global efficiency in the left habenula, the left pulvinar in the thalamus, the left dorso-lateral prefrontal cortex, and the right temporal pole, as well as a trend for decreased clustering in DMN nodes. In the reactive aggressive group, high levels of trait aggression were linked to lower global efficiency of the left habenula, and to lower rsFC between the left habenula and the left ventro-lateral prefrontal cortex, a core region involved in inhibitory control. Together with preclinical evidence, our findings in men underline the relevance of aberrant habenula-prefrontal connectivity for the severity of aggressive behavior. This article is part of the Special Issue entitled 'Current status of the neurobiology of aggression and impulsivity'.

Reduced flow impacts salmonid smolt emigration in a river with low-head weirs.

The impacts of large dams on the hydrology and ecology of river systems are well understood, yet the impacts of low-head structures are poorly known. While impacts of small weirs on upstream-migrating fish have long been mitigated by fish ladders, it is assumed that downstream migration of surface-oriented fishes is unaffected under natural flow regimes. To test this, the effects of low-head weirs and the influence of river flow on the migration of brown trout (Salmo trutta) smolts in the River Tweed, UK, were examined. Movements of acoustic tagged smolts were quantified in 2010 and 2011 using automatic listening stations and manual tracking throughout the migration route. In both years, smolts exhibited major losses, most likely due to predators, with escapement rates of 19% in 2010 and 45% in 2011. Loss rates were greater in 2010 when flows were frequently below Q95 (20% of study period) compared to 2011 when more typical flows predominated (0% of study period below Q95). Smolts experienced significantly longer delays at weirs during 2010 than 2011, associated with the different hydrographs during emigration as well as weir design. Flow comparisons within the study periods and historical records show that low flows experienced in 2010 were not unusual. The swimming behaviour of smolts in relation to flow conditions differed between years, with smolts in 2010 increasing their rate of movement in relation to increasing flow at a faster rate than smolts in 2011. This is the first study to demonstrate river flow impacts on the migration success of wild salmonid smolts at small weirs. Because small weirs are common in rivers and because spring-summer low-flow periods may become more frequent with climate change (based on UKCIP09 models) and altered river hydrology, further research and improved management is needed to reduce the impacts of low river flows in combination with low-head weirs on salmonid smolt migration.

Situational changes in self-awareness influence 3- and 4-year-olds' self-regulation.

In adults, heightened self-awareness leads to adherence to socially valued norms, whereas lowered self-awareness is associated with antinormative behavior. Levels of self-awareness are influenced by environmental cues such as mirrors. Do situational changes in self-awareness also have an impact on preschoolers' self-regulation? Adherence to a socially valued standard was observed under different conditions of self-focus. In Experiment 1 the standard was prescribed ("don't look in the box"), and in Experiment 2 children had the opportunity to be altruistic. Heightened self-focus was induced using a large mirror. In a neutral condition, the nonreflective side of the mirror was shown. To lower self-focus, children wore a disguise. Preschoolers peeked less and showed more altruism when the mirror image was present. As found for adults, it appears that self-awareness leads 3- and 4-year-olds to adhere to salient social standards. These results suggest that self-focus has a socially adaptive regulatory function from an early age.

Ho:YLF pumped HBr laser.

A Ho:YLF laser pumped HBr molecular laser was developed that produced up to 2.5 mJ of energy in the 4 micron wavelength region. The Ho:YLF laser was fiber pumped using a commercial Tm:fibre laser. The Ho:YLF laser was operated in a single longitudinal mode via injection seeding with a narrow band diode laser which in turn was locked to one of the HBr transitions. The behavior of the HBr laser was described using a rate equation mathematical model and this was solved numerically. Good agreement both qualitatively and quantitatively between the model and experimental results was obtained.

The relevance of Vygotsky's theory of the "zone of proximal development' to the assessment of children with intellectual disabilities.

This paper reports a study which investigated the relevance of Vygotsky's concept of the "zone of proximal development' (ZPD) to the assessment of children with intellectual disabilities. The ZPD is the difference between a child's actual level of development shown by unassisted performance, and his or her potential level as indicated by assisted performance. This study aimed to test the validity of measuring the ZPD both among children with intellectual disabilities and in the area of map use. The results are discussed in terms of their bearing on the issues of assessment, instruction and the concept of intellectual disability.

Fungal transmission of plant viruses.

Thirty soilborne viruses or virus-like agents are transmitted by five species of fungal vectors. Ten polyhedral viruses, of which nine are in the family Tombusviridae, are acquired in the in vitro manner and do not occur within the resting spores of their vectors, Olpidium brassicae and O. bornovanus. Fungal vectors for other viruses in the family should be sought even though tombusviruses are reputed to be soil transmitted without a vector. Eighteen rod-shaped viruses belonging to the furo- and bymovirus groups and to an unclassified group are acquired in the in vivo manner and survive within the resting spores of their vector, O. brassicae, Polymyxa graminis, P. betae, and Spongospora subterranea. The viral coat protein has an essential role in in vitro transmission. With in vivo transmission a site in the coat protein-read through protein (CP-RT) of beet necrotic yellow vein furovirus determines vector transmissibility as does a site in a similar 98-kDa polyprotein of barley mild mosaic bymovirus. The mechanisms by which virions move (or are moved) into and out of the protoplasm of zoospores or of thalli needs study.

Involvement of the cucumber necrosis virus coat protein in the specificity of fungus transmission by Olpidium bornovanus.

Cucumber necrosis (CNV) and the cherry strain of tomato bushy stunt (TBSV-Ch) are tombusviruses which differ in transmissibility by the fungus Olpidium bornovanus (Sahtiyanci) Karling (= O. radicale Schwartz and Cook). Zoospores acquire and transmit CNV, but not TBSV-Ch, in the in vitro manner. To assess the role of the coat protein in the specificity of fungus transmission, reciprocal exchanges were made between the coat protein genes of these two viruses in full-length infectious cDNA clones. Virions containing a modified TBSV-Ch genome with the CNV coat protein gene were efficiently transmitted, but those containing a modified CNV genome with the TBSV-Ch coat protein gene were not. This is the first direct demonstration for the role of a viral coat protein in the specificity of transmission by a fungus.

Transmission of cucumber leaf spot virus by Olpidium radicale.

The ability of zoospores of four cultures of Olpidium radicale and one of O. brassicae to transmit viruses acquired in vitro from dilute virus solutions was compared. Transmission was demonstrated by infectivity and serological assays of the roots of cucumber seedlings 6 days after inoculation. A bulk culture of O. radicale, from cucumber plant roots collected near Nantes, France, a single-sporangial culture derived from it, and a single-sporangial culture from melon plant roots collected near Woodland, California, U.S.A., transmitted cucumber leaf spot virus (CLSV) and the cucumber fruit streak strain of CLSV (CLSV-FS). A bulk culture of O. radicale from melon plant roots collected at Montfavet, France, did not transmit CLSV or CLSV-FS. All four cultures transmitted cucumber necrosis and melon necrotic spot viruses, used as positive controls, but they did not transmit cucumber soil-borne, squash necrosis, petunia asteroid mosaic or tobacco necrosis viruses. In each of the trials a single-sporangial culture of O. brassicae from lettuce plant grown in California transmitted only tobacco necrosis virus.

Numerical investigation of a three-mirror resonator for a TE CO(2) laser.

A numerical model of a three-mirror resonator for a TE CO(2) laser was developed. This model was used to determine if a three-mirror resonator with an etalon could be used to ensure tunable single-mode action on the lower gain lines of CO(2). Single-mode pulse energies were also predicted and good agreement was found with experimentally measured values. An analysis of the thermal frequency drift of the resonator is also presented.