APLF (C2orf13) is a novel component of poly(ADP-ribose) signaling in mammalian cells

APLF is a novel protein of unknown function that accumulates at sites of chromosomal DNA strand breakage via forkhead-associated (FHA) domain-mediated interactions with XRCC1 and XRCC4. APLF can also accumulate at sites of chromosomal DNA strand breaks independently of the FHA domain via an unidentified mechanism that requires a highly conserved C-terminal tandem zinc finger domain. Here, we show that the zinc finger domain binds tightly to poly(ADP-ribose), a polymeric posttranslational modification synthesized transiently at sites of chromosomal damage to accelerate DNA strand break repair reactions. Protein poly(ADP-ribosyl)ation is tightly regulated and defects in either its synthesis or degradation slow global rates of chromosomal single-strand break repair. Interestingly, APLF negatively affects poly(ADP-ribosyl)ation in vitro, and this activity is dependent on its capacity to bind the polymer. In addition, transient overexpression in human A549 cells of full-length APLF or a C-terminal fragment encoding the tandem zinc finger domain greatly suppresses the appearance of poly(ADP-ribose), in a zinc finger-dependent manner. We conclude that APLF can accumulate at sites of chromosomal damage via zinc finger-mediated binding to poly(ADP-ribose) and is a novel component of poly(ADP-ribose) signaling in mammalian cells

The effect of neural adaptation of population coding accuracy

Most neurons in the primary visual cortex initially respond vigorously when a preferred stimulus is presented, but adapt as stimulation continues. The functional consequences of adaptation are unclear. Typically a reduction of firing rate would reduce single neuron accuracy as less spikes are available for decoding, but it has been suggested that on the population level, adaptation increases coding accuracy. This question requires careful analysis as adaptation not only changes the firing rates of neurons, but also the neural variability and correlations between neurons, which affect coding accuracy as well. We calculate the coding accuracy using a computational model that implements two forms of adaptation: spike frequency adaptation and synaptic adaptation in the form of short-term synaptic plasticity. We find that the net effect of adaptation is subtle and heterogeneous. Depending on adaptation mechanism and test stimulus, adaptation can either increase or decrease coding accuracy. We discuss the neurophysiological and psychophysical implications of the findings and relate it to published experimental data.Comment: 35 pages, 8 figure

Submillimetre dust polarisation and opacity in the HD163296 protoplanetary ring system

We present ALMA images of the sub-mm continuum polarisation and spectral index of the protoplanetary ringed disk HD163296. The polarisation fraction at 870{\mu}m is measured to be ~0.9% in the central core and generally increases with radius along the disk major axis. It peaks in the gaps between the dust rings, and the largest value (~4%) is found between rings 1 and 2. The polarisation vectors are aligned with the disk minor axis in the central core, but become more azimuthal in the gaps, twisting by up to +/-9degrees in the gap between rings 1 and 2. These general characteristics are consistent with a model of self-scattered radiation in the ringed structure, without requiring an additional dust alignment mechanism. The 870/1300{\mu}m dust spectral index exhibits minima in the centre and the inner rings, suggesting these regions have high optical depths. However, further refinement of the dust or the disk model at higher resolution is needed to reproduce simultaneously the observed degree of polarisation and the low spectral index.Comment: 5 pages +2 pages supplemental data. v2 - revised figures and final values; conclusions unchange

On partial skew Armendariz rings

In this paper we consider rings R with a partial action α of an infinite cyclic group G on R. We introduce the concept of partial skew Armendariz rings and partial α-rigid rings. We show that partial α-rigid rings are partial skew Armendariz rings and we give necessary and sufficient conditions for R to be a partial skew Armendariz ring. We study the transfer of Baer property, a.c.c. on right annhilators property, right p.p. property and right zip property between R and R[x;α]. We also show that R[x;α] and R⟨x;α⟩ are not necessarily associative rings when R satisfies the concepts mentioned above

Abundance trends of highly migratory species in the Atlantic Ocean: accounting for water temperature profiles

Relative abundance trends of highly migratory species (HMS) have played a central role in debates over the health of global fisheries. However, such trends have mostly been inferred from fishery catch rates, which can provide misleading signals of relative abundance. While many biases are accounted for through traditional catch rate standardization, pelagic habitat fished is rarely directly considered. Using a method that explicitly accounts for temperature regimes, we analysed data from the US pelagic longline fishery to estimate relative abundance trends for 34 HMS in the Atlantic Ocean from 1987 through 2013. This represents one of the largest studies of HMS abundance trends. Model selection emphasized the importance of accounting for pelagic habitat fished with water column temperature being included in nearly every species’ model, and in extreme cases, a temperature variable explained 50–60% of the total deviance. Our estimated trends represent observations from one fishery only, and a more integrated stock assessment should form the basis for conclusions about stock status overall. Nonetheless, our trends serve as indicators of stock abundance and they suggest that a majority of HMS (71% of analysed species) are either declining in relative abundance or declined initially with no evidence of rebuilding. Conversely, 29% of the species exhibited stable, increasing, or recovering trends; however, these trends were more prevalent among tunas than either billfishes or sharks. By estimating the effects of pelagic habitat on fishery catch rates, our results can be used in combination with ocean temperature trends and forecasts to support bycatch avoidance and other time-area management decisions

A Novel Solid State Ultracapacitor

Novel dielectric materials were researched to develop an internal barrier layer capacitor that is fully solid state. These materials included reduced nanoparticles of barium titanate that were coated with various atomic layer deposited oxides. The nanoparticle powders were then densified into pellets and characterized using a dielectric test fixture over a frequency range of 20 Hz to 2 MHz. Densification and sintering were evaluated using scanning electron microscopic techniques. Ultimately, the samples showing the most promising electrical characteristics of permittivity, dissipation factor and equivalent series resistance were chosen to manufacture devices for subsequent testing