Cool spots on the surface of the active giant PZ Mon

Based on the multiband (BVRIJHKL) photometric observations of the active red giant PZ Mon performed for the first time in the winter season of 2017-2018, we have determined the main characteristics of the spotted stellar surface in a parametric three-spot model. The unspotted surface temperature is Teff=4730 K, the temperature of the cool spots is Tspot=3500 K, their relative area is about 41%, and the temperature of the warm spots is Twarm=4500 K with a maximum relative area up to 20%. The distribution of spots over the stellar surface has been modeled. The warm spots have been found to be distributed at various longitudes in the hemisphere on the side of the secondary component and are most likely a result of its influence.Comment: 5 pages, 7 figure

Inositol Trisphosphate and Cyclic ADP-Ribose–Mediated Release of Ca2+ from Single Isolated Pancreatic Zymogen Granules

AbstractIn pancreatic acinar cells low (physiological) agonist concentrations evoke cytosolic Ca2+ spikes specifically in the apical secretory pole that contains a high density of secretory (zymogen) granules (ZGs). Inositol 1,4,5-trisphosphate (IP3) is believed to release Ca2+ from the endoplasmic reticulum, but we have now tested whether the Ca2+-releasing messengers IP3 and cyclic ADP-ribose (cADPr) can liberate Ca2+ from ZGs. In experiments on single isolated ZGs, we show using confocal microscopy that IP3 and cADPr evoke a marked decrease in the free intragranular Ca2+ concentration. Using a novel high resolution method, we have measured changes in the Ca2+ concentration in the vicinity of an isolated ZG and show that IP3 and cADPr cause rapid Ca2+ release from the granule, explaining the agonist-evoked cytosolic Ca2+ rise in the secretory pole

Macrozoobenthos communities along the marine pipeline route at the Lunskoye field (shelf of northeastern Sakhalin) and their long-term variability

Results of benthos surveys conducted along the marine pipeline at the Lunskoe oilfield in July of 2006-2010 are presented. The sediment samples were taken at 59 stations with the depth 0-45 m by van Veen grab (0.05 m2, 0.11 m2, 0.25 m2), 1-3 samples per each station, in total 375 samples. Macrozoobenthos was extracted from the sampled sediments by seawater washing through 1 mm sieve and preserved by 4 % buffered formaldehyde. Its species composition, biomass and abundance were determined according to standard techniques. Eight phyla and 257 species of macrozoobenthos are identified in the surveyed area, mainly amphipods (103 species) and polychaetes (60 species). Its mean biomass amounts to 192.2 ± 12.1 g/m2, the mean distribution density - 28331.8 ± 3055.9 ind./m2. Cumaceans and amphipod crustaceans dominate by their number and bivalve molluscs and cumaceans - by their biomass. Six benthic communities are revealed by the hierarchical agglomerative method of multidimensional clustering with group-average linking of Bray-Curtis similarities, after 4th root transformation of the species biomass values (PRIMER software). Type of the bottom sediments and depth are the main factors determining characteristics and distribution patterns of the benthic assemblages

Macrozoobenthos communities in the area of marine pipeline route at Piltun-Astokhskoye oil field (shelf of northeastern Sakhalin) and their long-term variability

Results of macrozoobenthos surveys (in total 86 stations, 432 sediment samples) in the area of marine pipeline route at Piltun-Astokhskoye oil field in July of 2007-2010 are presented. The sediment samples were collected by van Veen sampler (1-3 samples per site from the area 0.05 m2, 0.11 m2, or 0.25 m2) at the depth 0-45 m. The samples were washed by sea water through the sieve with mesh 1 mm, and the residues including macrobenthos were preserved by 4 % buffered formaldehyde for later processing with total identification of macrozoobenthos (species composition, abundance and biomass) in the laboratories of Far-Eastern Research Hydrometeorological Institute and Institute of Marine Biology in Vladivostok, following to standard techniques. The data were analysed using the PRIMER software including multidimensional cluster analysis of samples by hierarchical agglomerative method of group-average linking based on Bray-Curtis similarity of the macrozoobenthos species composition by biomass. In total, 272 species of macrozoobenthos are identified at the surveyed area, with the highest species number for amphipods (86 species) and polychaetes (72 species). Mean total abundance of macrozoobenthos is 26556.4 ± 2660.9 ind/m2, its mean total biomass is 669.7 ± 40.3 g/m2. Cumaceans and amphipod crustaceans are the most numerous groups; sea-urchins, bivalves and cumaceans have the highest biomass. Five benthic communities are defined by cluster analysis. There is concluded that the bottom sediments and depth are the main factors determining the characteristics and distribution patterns of benthic assemblages at present time

Efficient Maximum Likelihood Estimation of Kinetic Rate Constants from Macroscopic Currents

A new method is described that accurately estimates kinetic constants, conductance and number of ion channels from macroscopic currents. The method uses both the time course and the strength of correlations between different time points of macroscopic currents and utilizes the property of semiseparability of covariance matrix for computationally efficient estimation of current likelihood and its gradient. The number of calculation steps scales linearly with the number of channel states as opposed to the cubic dependence in a previously described method. Together with the likelihood gradient evaluation, which is almost independent of the number of model parameters, the new approach allows evaluation of kinetic models with very complex topologies. We demonstrate applicability of the method to analysis of synaptic currents by estimating accurately rate constants of a 7-state model used to simulate GABAergic macroscopic currents

Segmental and descending control of primary afferent input to the spinal lamina X

Despite being involved in a number of functions, such as nociception and locomotion, spinal lamina X remains one of the least studied central nervous system regions. Here, we show that Aδ- and C-afferent inputs to lamina X neurons are presynaptically inhibited by homo- and heterosegmental afferents as well as by descending fibers from the corticospinal tract, dorsolateral funiculus, and anterior funiculus. Activation of descending tracts suppresses primary afferent-evoked action potentials and also elicits excitatory (mono- and polysynaptic) and inhibitory postsynaptic responses in lamina X neurons. Thus, primary afferent input to lamina X is subject to both spinal and supraspinal control being regulated by at least 5 distinct pathways

Functional Characterization of Lamina X Neurons in ex-Vivo Spinal Cord Preparation

Functional properties of lamina X neurons in the spinal cord remain unknown despite the established role of this area for somatosensory integration, visceral nociception, autonomic regulation and motoneuron output modulation. Investigations of neuronal functioning in the lamina X have been hampered by technical challenges. Here we introduce an ex-vivo spinal cord preparation with both dorsal and ventral roots still attached for functional studies of the lamina X neurons and their connectivity using an oblique LED illumination for resolved visualization of lamina X neurons in a thick tissue. With the elaborated approach, we demonstrate electrophysiological characteristics of lamina X neurons by their membrane properties, firing pattern discharge and fiber innervation (either afferent or efferent). The tissue preparation has been also probed using Ca2+ imaging with fluorescent Ca2+ dyes (membrane-impermeable or -permeable) to demonstrate the depolarization-induced changes in intracellular calcium concentration in lamina X neurons. Finally, we performed visualization of subpopulations of lamina X neurons stained by retrograde labeling with aminostilbamidine dye to identify sympathetic preganglionic and projection neurons in the lamina X. Thus, the elaborated approach provides a reliable tool for investigation of functional properties and connectivity in specific neuronal subpopulations, boosting research of lamina X of the spinal cord

Distinct mechanisms of signal processing by lamina I spino-parabrachial neurons

Lamina I spino-parabrachial neurons (SPNs) receive peripheral nociceptive input, process it and transmit to the supraspinal centres. Although responses of SPNs to cutaneous receptive field stimulations have been intensively studied, the mechanisms of signal processing in these neurons are poorly understood. Therefore, we used an ex-vivo spinal cord preparation to examine synaptic and cellular mechanisms determining specific input-output characteristics of the neurons. The vast majority of the SPNs received a few direct nociceptive C-fiber inputs and generated one spike in response to saturating afferent stimulation, thus functioning as simple transducers of painful stimulus. However, 69% of afferent stimulation-induced action potentials in the entire SPN population originated from a small fraction (19%) of high-output neurons. These neurons received a larger number of direct Ad- and C-fiber inputs, generated intrinsic bursts and efficiently integrated a local network activity via NMDA-receptor-dependent mechanisms. The high-output SPNs amplified and integrated the nociceptive input gradually encoding its intensity into the number of generated spikes. Thus, different mechanisms of signal processing allow lamina I SPNs to play distinct roles in nociception.The authors thank Mr. Andrew Dromaretsky for the technical assistance. P.B. was supported by the National Academy of Sciences of Ukraine (NASU), grant NASU # 0116U004470, grant NASU#67/15-Н. N.V. was supported by the NASU Biotechnology and NASU-KNU grants; NIH 1R01NS113189-01. B.V.S. was supported by the FEDER funds through the COMPETE 2020 (POCI), Portugal 2020, and by the FCT project PTDC/NEU-NMC/1259/2014 (POCI-01-0145-FEDER-016588

Wildfire smoke in the Siberian Arctic in summer: source characterization and plume evolution from airborne measurements

We present airborne measurements of carbon dioxide (CO<sub>2</sub>), carbon monoxide (CO), ozone (O<sub>3</sub>), equivalent black carbon (EBC) and ultra fine particles over North-Eastern Siberia in July 2008 performed during the YAK-AEROSIB/POLARCAT experiment. During a "golden day" (11 July 2008) a number of biomass burning plumes were encountered with CO mixing ratio enhancements of up to 500 ppb relative to a background of 90 ppb. Number concentrations of aerosols in the size range 3.5–200 nm peaked at 4000 cm<sup>−3</sup> and the EBC content reached 1.4 μg m<sup>−3</sup>. These high concentrations were caused by forest fires in the vicinity of the landing airport in Yakutsk where measurements in fresh smoke could be made during the descent. We estimate a combustion efficiency of 90 ± 3% based on CO and CO<sub>2</sub> measurements and a CO emission factor of 65.5 ± 10.8 g CO per kilogram of dry matter burned. This suggests a potential increase in the average northern hemispheric CO mixing ratio of 3.0–7.2 ppb per million hectares of Siberian forest burned. For BC, we estimate an emission factor of 0.52 ± 0.07 g BC kg<sup>−1</sup>, comparable to values reported in the literature. The emission ratio of ultra-fine particles (3.5–200 nm) was 26 cm<sup>−3</sup> (ppb CO)<sup>−1</sup>, consistent with other airborne studies. <br><br> The transport of identified biomass burning plumes was investigated using the FLEXPART Lagrangian model. Based on sampling of wildfire plumes from the same source but with different atmospheric ages derived from FLEXPART, we estimate that the e-folding lifetimes of EBC and ultra fine particles (between 3.5 and 200 nm in size) against removal and growth processes are 5.1 and 5.5 days respectively, supporting lifetime estimates used in various modelling studies