1,457 research outputs found
Heroin abusers’ performance on the Tower of London Test relates to the baseline EEG alpha2 mean frequency shifts
No full textPlanning function deficit is the most consistent finding in neuropsychological studies of heroin addicts. The performance on the Tower of London Test (TLT) correlated with the duration of daily heroin abuse (DDHA) in our previous study. Alpha2 mean frequency in anterior/central derivations was also predicted by DDHA in the same patient population. This retrospective study was undertaken in order to understand better the relationships between observed neurological deviations in heroin abusers. Thirty-three heroin addicts and 12 healthy males were evaluated with 14 neuropsychological tests and resting eyes-closed electroencephalography (EEG). Multivariate tests showed that performance on the difficult (five-move) problems of TLT was strongly predicted by the EEG alpha2 mean frequency shifts, and these relationships were generally mediated by chronic heroin length. However, post-hoc analyses at separate leads demonstrated that the relationships between cognitive variables and alpha2 mean frequencies in the left hemisphere were independent of chronic heroin effects, whereas elevation of alpha2 frequency in the right hemisphere was strongly predicted by chronic heroin intake length. The patients with extremely high alpha2 mean frequency at the left central region were especially prone to failure in TLT due to the inability of the hypothesized alpha2-generating network, which normally projects to the central and temporal derivations bilaterally and to the right posterior temporal derivation to function appropriately. Hence, it was concluded that planning dysfunction in heroin abusers is related to alpha2 mean frequency shifts predominantly at the central regions
EEG spectral power and mean frequencies in early heroin abstinence
No full textThe purpose of the present study was to investigate cumulative heroin effects on brain functioning by studying relationships between EEG spectral power and mean frequencies and heroin abusing history. Eyes closed resting EEG data were collected from the 19 monopolar electrode sites in 33 heroin abusers and 13 age-matched healthy volunteers. The mean age of the patients was 23.1±4.5, the duration of daily heroin abuse (DDHA) ranged from 4 to 44 months, the i.v. doses of heroin ranged from 0.04 to 1.00 g/day, the abstinence length ranged from 6 days to 4.5 months. GLM repeated measures procedure revealed a significant group effect on the distribution of the mean power spectrum between bands and mean frequencies in almost all analyzed derivations. Further analysis demonstrated that these intergroup differences were diversely related to at least three aspects of heroin taking history. Frequency shifts in alpha2 range, most prominent in frontal and central derivations, were related to duration of daily heroin consumption. Slowing of alpha1 mean frequency, most prominent in central, temporal and occipital derivations, was registered mainly in heroin addicts who abused high doses of the drug. Spectral power characteristics of brain electrical activities in our patient population were strongly predicted by abstinence length. The present results give grounds to suppose that chronic heroin taking induces neuronal oscillation frequency changes, that may contribute to the development of antisocial trends and some semantic processes disturbances in these patients. Supplementary neurophysiological deficit is characteristic for heroin addicts, who takes high doses of the drug, however, its relation to heroin abusing remains unclear. Pronounced desynchronization is observed in acute heroin withdrawal, and spectral power characteristics tend to normalize almost completely during several weeks of abstinence
Single and combined effects of sympathetic and parasympathetic activity on perceptual sensitivity and attention
No full textPulse rate and cephalic pulse volume were recorded from 17 male and 37 female normal subjects during performance of an attentional task under high and low stress conditions. Verbal threshold (perceptual sensitivity) and word recognition (attention) were assessed using a visual verbal recognition task. Subjects were divided at the median for pulse rate and pulse volume during baseline, instruction, and task periods and grouped in terms of these two measures to represent different patterns of parasympathetic (vagal) and sympathetic activity. Analysis of variance was used to examine the effects of gender, stress condition, and autonomic pattern on autonomic activity, perceptual sensitivity, and attentional performance. Gender showed significant effects for pulse rate with higher scores for women during the instruction and task periods. High stress reduced perceptual sensitivity and resulted in better attentional performance. Whereas stress-induced sympathetic activity was related to low perceptual sensitivity and good attentional performance, high sympathetic in conjunction with low vagal baseline activity predicted relatively high perceptual sensitivity and poor attentional performance. Low or high baseline activity in both autonomic systems predicted low perceptual sensitivity and good attentional performance. Predictions of perception and attention can be improved by examining the effects of patterns of sympathetic and parasympathetic activity
Umbilicaria platyrhiza Davydov 2022, sp. nov.
No full textUmbilicaria platyrhiza Davydov, sp. nov. (Figure 1, 2) MycoBank no. 841496 Similar to U. crustulosa, differing by apothecia with a single gyrus of sterile tissue, grey-brown to black lower surface with flattened to strap-like rhizinomorphs, smaller ascospores, and by producing umbilicaric acid. Type:— TURKEY. Prov. Izmir (35): southern slope of Yamanlar Dað, small valley N of Karþiyaka, 38°30’ N, 27°07’ E, elev. 125 m, on vertical siliceous rocks. 30 June 2001, V. John [V. John: Lichenes Anatolici Exsiccati, 171, as U. spodochroa Hoffm.] (holotype, M!, isotypes examined in ALTB! ex GZU, GZU!, LE L–1933!). Sequences of the holotype: ITS: KY947760; RPB2: KY972608; mtLSU: KY947904. Thallus 2–4 cm in diam. and 0.2–0.3 mm thick, umbilicate, monophyllous. Upper surface pale to dark grey, sometimes with a brown or violet tinge, lighter at the center, minutely rimose, pruinose, more rough and partly radially folded in the center, sometimes with branched to strap-like rhizinomorphs (Fig. 2C). Lower surface usually dirty ochre-brown to grey-brown and black, darker towards the center, rimose to coarsely papillate with abundant to scarce rhizinomorphs. Rhizinomorphs simple to few times branched under the sharp angle, often flattened to strap-like, ca. 1 mm long; colored at the base the same as the lower surface, and getting darker toward the tips, with rimose to papillate surface (Fig. 2A–B). Thalloconidia absent. Upper cortex paraplectenchymatous, brownish in the outer part and hyaline in the inner part, 25–60 μm, epicortex 12–30 μm, algal layer continuous, 38–100 μm thick, algae Trebouxioid, with cells (5–)7–10–13(–15) μm in diam., medulla colourless, more or less loose, 75–95 μm thick, lower cortex colourless, scleroplectenchymatous, 25–80 μm thick, including a colourless inner layer 20–34 μm thick and a brown outer layer 15–40 μm thick. Apothecia frequent at the periphery of thalli, ca. 1 mm in diam., disc first flat, with age becoming convex, i.e. broadly cone-like with a single central protruding gyrus of sterile tissue (Fig. 2D) with cells 5–9 μm diam. (Fig. 2E); epihymenium brown, 13–25 μm thick; hymenium yellowish 65–92 μm thick, hypothecium ochre to light brown, 40–130 μm thick; excipulum inner part yellowish, outer part brown; paraphyses septate, branched, 2.5 μm thick, sometimes slightly thickened at the tips, up to 3 μm; asci 50–60 × 20–30 μm; ascospores hyaline, simple, (14.0–) 16.0–17.5–18.5(–20.0) × (9.0–)9.5–11.5–13.0(–17.5) μm (N=60). Pycnidia at the periphery of thalli, 125–175 μm in diameter, covered by cortex and algal layer, with black prominent ostiole, the wall brown, 10 μm thick, pycnoconidia bacilliform, 3–4×1 μm. Chemistry: gyrophoric (major), umbilicaric (minor), and lecanoric (minor) acids detected by TLC and HPLC; medulla K–, C+ red, KC+ red, Pd–, UV–. Etymology: platyrhiza derived from Greek πλατύς – ‘wide, flat’, and ρίζα – ‘root’, with reference to the flattened rhizinomorphs. Ecology: Umbilicaria platyrhiza grows on siliceous rocks in maritime territories. Distribution: The species is so far known from only two localities in coastal territories of the Aegean Sea (Turkey, Izmir) and Black Sea (Bulgaria, Burgas). Additional specimens of Umbilicaria platyrhiza examined : BULGARIA. Burgas: loco Veselita skala dicto supra fl. Ropotamo prope inter Sozopol und Primorsko, alt. 30 m s. m. Ad saxa andesitica, 21 August 1977. A. Vežda [Exsicc. Lich. Sel. no. 1531, as U. spodochroa] (GZU –324242!, GZU –s.n.!, ALTB! ex GZU).Published as part of Davydov, Evgeny A., 2022, Umbilicaria platyrhiza-a new Mediterranean endemic species of the subgenus Papillophora (Umbilicariaceae, lichenized Ascomycota), pp. 143-148 in Phytotaxa 533 (2) on page 144, DOI: 10.11646/phytotaxa.533.2.3, http://zenodo.org/record/603631
Mexico: 30 years of neoliberal paradigm
No full textInterview with Vladimir Mikhailovich Davydov, Doctor of Economics, Corresponding Member of the Russian Academy of Sciences, Scientific Director of the Institute of Latin America of the Russian Academy of Sciences, Director of the Institute of Latin America of the Russian Academy of Sciences (1995-2017). Being one of the leading specialists in Latin American studies in Russia, Dr. Davydov is the author of more than 350 research papers. His works made a huge contribution to the study of socio-economic and political processes taking place in Latin America, as well as to the development of Iberoamericanism in Russia.The interview was conducted by: A.A. Habarta
Changes in the conformational parameters of 1-allylbenzotriazole in a mixed halide pi-complex [CuCl0.85Br0.15(C6H4N3CH2CH = CH2)] under the action of bromine atoms
No full textSingle crystals of [CuCl0.85Br0.15(C6H4N3CH2CH=CH2)] (1) were obtained by alternating current electrochemical synthesis; their X-ray structural investigation has been carried out (DARCh automatic diffractometer, MoK alpha radiation, theta/2 theta scanning; 1460 reflections with F >= 4 sigma(F), R=0.0517). The crystals are monoclinic, their space group is P2(1)/c, a=7.292(3) angstrom, b=17.947(8) angstrom, c=7.398(4) angstrom, beta=93.56(4)degrees, V=966(1) angstrom(3), Z=4). Complex I is close in structure to the previously investigated compound [CuCl(C6H4N3CH2CH=CH2)] (II). In both structures, the trigonal-pyramidal surroundings of the copper atom include two halide atoms (one is apical), a nitrogen atom, and a C=C group. The Cu2X2, dimers are associated into {[Cu2X2(C6H5N3CH2CH=CH2)]}(n) layers due to the bridging function of the 1-allylbenzotriazole molecule. In spite of the similar coordination polyhedra of the metal atoms and identical bridging function of the ligand molecule in I and II, the differences in the conformation parameters of the allyl group pi-coordinated by the copper(I) atom (trans-like in I and cis-like in II) caused by the presence of bromine atoms in the coordination sphere predetermine different structures of the organometallic [Cu2X2(C6H5N3CH2CH=CH2)](4) tetramer subunits in the layers and, as a consequence, formation of different crystal structures
Complexation between N-allylmorpholinium derivatives and copper(I) halides. Synthesis and crystal structure of pi-complex {[C4H8ONH(C3H5)](+)}(2)[CU2Cl4](2-)
No full textCopper(I) pi-complex {[C4H8ONH(C3H5)](+)}(2)[Cu2Cl4](2-) (I) was obtained by ac electrochemical synthesis from N-allylmorpholine hydrochloride and copper(II) chloride in ethanol and structurally characterized. In structure 1, copper and chlorine atoms form unique noncentrosymmetric Cu2Cl42- fragments. Both crystallographically independent N-allylmorpholinium cations are involved in the pi-interaction and are coordinated by the copper atom through the C=C bond of the allyl group. The trigonal pyramidal environment of the Cu(1) atom is composed of three chlorine atoms and the C=C bond, while the Cu(2) atom coordinates two chlorine atoms and the C=C bond forming a planar triangle. The extremely strong N-(HCl)-Cl-... hydrogen bond ((HCl)-Cl-... 2.2 angstrom) prevents the CI(1) atom from acting as a bridge and favors the formation of fragments Cu2Cl42-
Semiconductors V. 35, I. 12
No full textSemiconductors -- December 2001
Volume 35, Issue 12, pp. 1347-1417
ELECTRONIC AND OPTICAL PROPERTIES OF SEMICONDUCTORS
Paramagnetic Defects in Silicon Carbide Crystals Irradiated with Gamma-Ray Quanta
I. V. Ilyin, E. N. Mokhov, and P. G. Baranov
pp. 1347-1354 Full Text: PDF (117 kB)
Interaction of Hydrogen with Radiation Defects in p-Si Crystals
O. V. Feklisova, N. A. Yarykin, E. B. Yakimov, and J. Weber
pp. 1355-1360 Full Text: PDF (84 kB)
Electrical Properties of the Proton-Irradiated Semi-Insulating GaAs:Cr
V. N. Brudnyi and A. I. Potapov
pp. 1361-1365 Full Text: PDF (80 kB)
Dynamics of Nonequilibrium Gratings Induced in Silicon Films by Femtosecond Laser Pulses
M. F. Galyautdinov, V. S. Lobkov, S. A. Moiseev, and I. V. Negrashov
pp. 1366-1368 Full Text: PDF (55 kB)
Radiative Recombination via Direct Optical Transitions in In1 – xGaxAs (0 <= x <= 0.16) Solid Solutions
M. Aidaraliev, N. V. Zotova, S. A. Karandashev, B. A. Matveev, M. A. Remennyi, N. M. Stus', and G. N. Talalakin
pp. 1369-1371 Full Text: PDF (49 kB)
Effect of Structural Imperfection on the Spectrum of Deep Levels in 6H-SiC
A. A. Lebedev, D. V. Davydov, A. S. Tregubova, E. V. Bogdanova, M. P. Shcheglov, and M. V. Pavlenko
pp. 1372-1374 Full Text: PDF (457 kB)
SEMICONDUCTOR STRUCTURES, INTERFACES, AND SURFACES
The Contact of Metal with Silicon Carbide: Schottky Barrier Height in Relation to SiC Polytype
S. Yu. Davydov, A. A. Lebedev, O. V. Posrednik, and Yu. M. Tairov
pp. 1375-1377 Full Text: PDF (35 kB)
LOW-DIMENSIONAL SYSTEMS
Ostwald Ripening of Quantum-Dot Nanostructures
R. D. Vengrenovich, Yu. V. Gudyma, and S. V. Yarema
pp. 1378-1382 Full Text: PDF (60 kB)
Kinetics of Exciton Photoluminescence in Low-Dimensional Silicon Structures
A. V. Sachenko, É. B. Kaganovich, É. G. Manoilov, and S. V. Svechnikov
pp. 1383-1389 Full Text: PDF (145 kB)
Renormalization of Energy Spectrum of Quantum Dots under Vibrational Resonance Conditions
A. V. Fedorov, A. V. Baranov, A. Itoh, and Y. Masumoto
pp. 1390-1397 Full Text: PDF (111 kB)
AMORPHOUS, VITREOUS, AND POROUS SEMICONDUCTORS
Scanning Tunneling Spectroscopy of a-C:H and a-C:(H, Cu) Films Prepared by Magnetron Sputtering
T. K. Zvonareva, V. I. Ivanov-Omskii, V. V. Rozanov, and L. V. Sharonova
pp. 1398-1403 Full Text: PDF (78 kB)
PHYSICS OF SEMICONDUCTOR DEVICES
InAsSb/InAsSbP Double-Heterostructure Lasers Emitting in the 3–4 µm Spectral Range
T. N. Danilova, A. N. Imenkov, N. M. Kolchanova, and Yu. P. Yakovlev
pp. 1404-1417 Full Text: PDF (183 kB)Archived web conten
GUADALUPIAN BRACHIOPODS FROM DJEBEL TEBAGA DE MEDENINE, SOUTH TUNISIA
No full textHere we describe a Guadalupian brachiopod fauna from units III to V of the shallow water carbonate succession cropping out at Djebel Tebaga de Medenine, South Tunisia. The fauna comprises 29 taxa of the orders Productida, Orthotetida, Orthida, Rhynchonellida, Athyridida, Spiriferida and Terebratulida, whose distribution is consistent with the Wordian-Capitanian age suggested by the associated fusulinids and conodonts. Most of the brachiopod taxa are pedicle attached genera or cemented ones and thus were permanently attached, and only two were free living concavo-convex semi-infaunal genera; this indicates that they were mostly living in high energy environmental settings, where the settling strategies require firm attachment to the substrate at shallow depth under the influence of fair-weather waves. The brachiopods from South Tunisia are very similar to the fauna from the allochthonous limestones of Pietra di Salomone, Rupe del Passo di Burgio and Rocca di San Benedetto of Sosio Valley, Sicily, Italy, a fauna which is also dominated by cemented and pediculate taxa. Both regions were located at palaeoequatorial latitudes in the western termination of the Tethyan Gulf during Middle Permian time
Umbilicaria rhizinata Krzewicka 2010
No full textUmbilicaria rhizinata (Frey & Poelt) Krzewicka (2010: 491) Mycobank no. 548351 Umbilicaria decussata (Vill.) Zahlbr. var. rhizinata Frey & Poelt (Poelt 1977: 419). Type:— NEPAL. Mahalangur: Himal Khumbu, Moränen des Lobuche-Gletschers bei Lobuche, elev. 4950–5000 m, September 1962, J. Poelt L247a (lectotype M–0035585!; isolectotype M–0035586!). Umbilicaria aprina Nyl. var. halei Llano (1956: 183), syn. nov. Type:— CANADA. N.W.T.: Baffin Island, head of Clyde Fiord, on exposed gneiss boulders, 26 August 1950, M. E. Hale 450 (holotype MIN–664956!, Fig. 1). The holotype specimen of U. aprina var. halei has a similar morphology to the Himalayan U. rhizinata: small size, dark grey granulate upper surface, lower surface covered with black patches of thalloconidia in the central part only, and scarce dichotomous pale rhizinomorphs (Fig. 1). Thalloconidia are sphaerical to ellipsoid, brown to dark brown 3- or 4-celled when mature, but often also 2- or rarely 1-celled (Fig. 2). The sizes were (12.6–)15.0–16.2–17.5(–18.7) × (10.7–)12.6–13.7–14.9(–16.5) μm for (3-)4-celled (n=25), (11.6–)12.8–13.7–14.9(–16.5) × (8.0–)8.7–9.7–10.7(–11.7) μm for 2-celled (n=25), and (8.1–)9.3–10.3–11.4(–12.0) × (7.6–)8.5–9.5–10.6(–11.4) μm for 1-celled thalloconidia (n=25). The wall was 1.3–1.8(2.8) μm. The average size for all types of thalloconidia is 10.9–13.6–16.4 × 8.8–11.0– 13.2 μm which agrees well with the data presented by Krzewicka (2010) for U. rhizinata. All the remaining characters of U. aprina var. halei also perfectly fit the circumscription of U. rhizinata, except, none of the three specimens of the U. aprina var. halei holotype has a distinct reticulate pattern at the centre. They are coarsely pruinose with crystals positioned centrally near the umbo, but lack a reticulate pattern. Additionally, examined specimens from the Altai Mts. are only occasionally reticulate at the centre. This can be explained by the smaller size of both the holotype and the Altaian specimens (0.8–1.3 cm v. 1–2(–3) cm of U. rhizinata). As has been shown in phylogenies (Davydov et al. 2017), U. rhizinata is closely related to U. aprina, and only distantly related to U. decussata, which consistently possesses this reticulate pattern. Therefore, this character should be used with care as a diagnosis for U. rhizinata. Thus, it is proposed that U. aprina var. halei be reduced to synonymy with U. rhizinata. Umbilicaria rhizinata resembles immature U. aprina, but differs in its 3–4 celled thalloconidia. Due to the different conception of U. aprina var. halei by Wei & Jiang (1993) who did not pay attention to thalloconidium septation, material cited by them should be re-identified. Based on the information on the apothecia of U. aprina var. halei given in Wei & Jiang (1993) their material probably belongs to U. aprina. Umbilicaria rhizinata was previously known from Nepal and Stanovoye Nagor’e Highlands (South Siberia, Russia) in Asia, Tanzania in Africa, and Bolivia in South America (Poelt 1977, Krzewicka 2010, Davydov et al. 2019a). Further populations in the Altai Mts. both in Russia and China are recorded here. So, we have at least one verified locality for China – in Xinjiang. Selected specimens examined. RUSSIA. Altai Territory: Altai Mts., Korgonsky range, headwaters of Sentelek River, 51°03’ N, 83°43’ E, elev. 1900–2200 m, mountain tundra, 19 August 1996. E. A. Davydov 5350 (ALTB); Republic of Altai: Katunsky range, Ak-Kem River, stone fields and rocks, 49°59’15.6’’ N, 86°35’09.3’’ E, elev. 2686 m, 9 August 2009. E. A. Davydov 6879 (ALTB).— CHINA. Xinjiang: South Altai range, 49°01’41’’ N, 86°50’38’’ E, elev. 2300–2600 m, 17 July 2007. Davydov 6542 (ALTB).Published as part of Davydov, Evgeny A., 2022, On the status of Umbilicaria aprina var. halei and U. canescens (Umbilicariaceae, lichenized Ascomycota), pp. 91-97 in Phytotaxa 533 (1) on pages 92-93, DOI: 10.11646/phytotaxa.533.1.6, http://zenodo.org/record/597407
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