Synchronized single electron emission from dynamical quantum dots

We study synchronized quantized charge pumping through several dynamical quantum dots (QDs) driven by a single time modulated gate signal. We show that the main obstacle for synchronization being the lack of uniformity can be overcome by operating the QDs in the decay cascade regime. We discuss the mechanism responsible for lifting the stringent uniformity requirements. This enhanced functionality of dynamical QDs might find applications in nanoelectronics and quantum metrology.Comment: 4 pages, 3 figures, submitted to AP

Diurnal inhibition of NMDA-EPSCs at rat hippocampal mossy fibre synapses through orexin-2 receptors.

Diurnal release of the orexin neuropeptides orexin-A (Ox-A, hypocretin-1) and orexin-B (Ox-B, hypocretin-2) stabilises arousal, regulates energy homeostasis and contributes to cognition and learning. However, whether cellular correlates of brain plasticity are regulated through orexins, and whether they do so in a time-of-day-dependent manner, has never been assessed. Immunohistochemically we found sparse but widespread innervation of hippocampal subfields through Ox-A- and Ox-B-containing fibres in young adult rats. The actions of Ox-A were studied on NMDA receptor (NMDAR)-mediated excitatory synaptic transmission in acute hippocampal slices prepared around the trough (Zeitgeber time (ZT) 4-8, corresponding to 4-8 h into the resting phase) and peak (ZT 23) of intracerebroventricular orexin levels. At ZT 4-8, exogenous Ox-A (100 nm in bath) inhibited NMDA receptor-mediated excitatory postsynaptic currents (NMDA-EPSCs) at mossy fibre (MF)-CA3 (to 55.6 ± 6.8% of control, P = 0.0003) and at Schaffer collateral-CA1 synapses (70.8 ± 6.3%, P = 0.013), whereas it remained ineffective at non-MF excitatory synapses in CA3. Ox-A actions were mediated postsynaptically and blocked by the orexin-2 receptor (OX2R) antagonist JNJ10397049 (1 μm), but not by orexin-1 receptor inhibition (SB334867, 1 μm) or by adrenergic and cholinergic antagonists. At ZT 23, inhibitory effects of exogenous Ox-A were absent (97.6 ± 2.9%, P = 0.42), but reinstated (87.2 ± 3.3%, P = 0.002) when endogenous orexin signalling was attenuated for 5 h through i.p. injections of almorexant (100 mg kg(-1)), a dual orexin receptor antagonist. In conclusion, endogenous orexins modulate hippocampal NMDAR function in a time-of-day-dependent manner, suggesting that they may influence cellular plasticity and consequent variations in memory performance across the sleep-wake cycle

High abundances of neurotrophin 3 in atopic dermatitis mast cell

<p>Abstract</p> <p>Background</p> <p>Neurotrophin 3 (NT-3) is a member of the neurotrophin family, a group of related proteins that are known to regulate neuro-immune interactions in allergic diseases. Their cellular sources and role in the recruitment of mast cell precursors in atopic dermatitis have not been characterized in detail so far.</p> <p>Objective</p> <p>Characterize NT-3 on a transcriptional and translational level in individuals with atopic dermatitis with special focus on mast cells.</p> <p>Methods</p> <p>To meet this objective NT-3 levels in the serum of AD patients were measured, the effect of NT-3 on keratinocytes was evaluated and the gene expression and regulation assessed using ELISA, immunohistochemistry and RNA quantification.</p> <p>Results</p> <p>Systemic levels of NT-3 were found to be higher in individuals with AD as compared to healthy controls. A distinct genetic expression was found in the various cells of the skin. In lesional mast cells of individuals with atopic dermatitis an increased amount of NT-3 was apparent. Functional <it>in vitro </it>experiments demonstrated that NT-3 stimulation led to a suppression of IL-8 secretion by HaCat cells.</p> <p>Conclusion</p> <p>These findings could imply a role for NT-3 in the pathogenesis of allergic skin diseases.</p

The Missing Angle: Ecosystem Consequences of Phenological Mismatch

Climate change leads to unequal shifts in the phenology of interacting species, such as consumers and their resources, leading to potential phenological mismatches. While studies have investigated how phenological mismatch affects wild populations, we still lack studies and a framework for investigating how phenological mismatch affects ecosystems, particularly nutrient cycling

Galaxy merger histories and the role of merging in driving star formation at z>1

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.We use Horizon-AGN, a hydrodynamical cosmological simulation, to explore the role of mergers in the evolution of massive (M > 10^10 MSun) galaxies around the epoch of peak cosmic star formation (1zR(4:1 3 are 'blue' (i.e. have significant associated star formation), the proportion of 'red' mergers increases rapidly at ztodays stellar mass was formed.Peer reviewe

Interactions among climate, topography and herbivory control greenhouse gas (CO2, CH4 and N2O) fluxes in a subarctic coastal wetland

High-latitude ecosystems are experiencing the most rapid climate changes globally, and in many areas these changes are concurrent with shifts in patterns of herbivory. Individually, climate and herbivory are known to influence biosphere-atmosphere greenhouse gas (GHG) exchange; however, the interactive effects of climate and herbivory in driving GHG fluxes have been poorly quantified, especially in coastal systems that support large populations of migratory waterfowl. We investigated the magnitude and the climatic and physical controls of GHG exchange within the Yukon-Kuskokwim Delta in western Alaska across four distinct vegetation communities formed by herbivory and local microtopography. Net CO2 flux was greatest in the ungrazed Carex meadow community (3.97 ± 0.58 [SE] µmol CO2 m−2 s−1), but CH4 flux was greatest in the grazed community (14.00 ± 6.56 nmol CH4 m−2 s−1). The grazed community is also the only vegetation type where CH4 was a larger contributor than CO2 to overall GHG forcing. We found that vegetation community was an important predictor of CO2 and CH4 exchange, demonstrating that variation in regional gas exchange is best explained when the effect of grazing, determined by the difference between grazed and ungrazed communities, is included. Further, we identified an interaction between temperature and vegetation community, indicating that grazed regions could experience the greatest increases in CH4 emissions with warming. These results suggest that future GHG fluxes could be influenced by both climate and by changes in herbivore population dynamics that expand or contract the vegetation community most responsive to future temperature change

Early Goose Arrival Increases Soil Nitrogen Availability More Than an Advancing Spring in Coastal Western Alaska

An understudied aspect of climate change-induced phenological mismatch is its effect on ecosystem functioning, such as nitrogen (N) cycling. Migratory herbivore arrival time may alter N inputs and plant–herbivore feedbacks, whereas earlier springs are predicted to increase N cycling rates through warmer temperatures. However, the relative importance of these shifts in timing and how they interact to affect N cycling are largely unknown. We conducted a 3-year factorial experiment in coastal western Alaska that simulated different timings of Pacific black brant (Branta bernicla nigricans) arrival (3 weeks early, typical, 3 weeks late, or no-grazing) and the growing season (ca. 3 weeks advanced and ambient) on adsorbed and mobile inorganic (NH4+–N, NO3-–N) and mobile organic N (amino acid) pools. Early grazing increased NH4+–N, NO3-–N, and amino acids by 103%, 119%, and 7%, respectively, whereas late grazing reduced adsorbed NH4+–N and NO3−–N by 16% and 17%, respectively. In comparison, the advanced growing season increased mobile NH4+–N by 26%. The arrival time by geese and the start of the season did not interact to influence soil N availability. While the onset of spring in our system is advancing at twice the rate of migratory goose arrival, earlier goose migration is likely to be more significant than the advances in springs in influencing soil N, although both early goose arrival and advanced springs are likely to increase N availability in the future. This increase in soil N resources can have a lasting impact on plant community composition and productivity in this N-limited ecosystem