Reduced Spontaneous Eye Blink Rates in Recreational Cocaine Users: Evidence for Dopaminergic Hypoactivity

Chronic use of cocaine is associated with a reduced density of dopaminergic D2 receptors in the striatum, with negative consequences for cognitive control processes. Increasing evidence suggests that cognitive control is also affected in recreational cocaine consumers. This study aimed at linking these observations to dopaminergic malfunction by studying the spontaneous eyeblink rate (EBR), a marker of striatal dopaminergic functioning, in adult recreational users and a cocaine-free sample that was matched on age, race, gender, and personality traits. Correlation analyses show that EBR is significantly reduced in recreational users compared to cocaine-free controls, suggesting that cocaine use induces hypoactivity in the subcortical dopamine system

Infrared spectra of three M(I)M(III)S(2) type synthetic minerals (M(I)=Ag or Tl, M(III)=Sb or As)

The infrared spectra of three compounds of the M(I)M(III)S(2) type (smithite, AgAsS2; weissbergite, TlSbS2; and miargyrite, AgSbS2) were studied at room temperature (RT) and at the boiling temperature of liquid nitrogen (LNT). The infrared spectrum of smithite was compared with that of the formally analogous mineral lorandite, TlAsS2. Although the mentioned synthetic minerals have crystal structures which differ from each other, the infrared spectra of smithite and lorandite, on the one hand, and of weissbergite and miargyrite on the other, are similar. The analysis of the spectra indicate that the Tl-S interaction has a more pronounced ionic character than the Ag-S one

Landslide characterization in the Polog Region (R.N. Macedonia) by innovative and conventional methods

The paper presents the preliminary results of an ongoing international multidisciplinary project funded by the United Nations Development Programme (UNDP) over the Polog Region in R.N. Macedonia. The combined effects of a complex geological setting, an articulate morphology and particular climate conditions make the Polog Region one of the most landslide-prone areas in the country. Over the study area (extending for approximately 1000 km2), preliminary landslide susceptibility studies were performed; however, the extent of landslide hazard in the region needs to be understood to a higher level of detail. The aim of the project is to detect critical sediment sources in the Polog Region and propose technical measures - at a feasibility study level - for the areas exposed to the highest hazard level. In the first stage, via the joint contribution of geologists/geomorphologists, hydrologists, geotechnical and hydraulic engineers, the activities focused on the preparation of thematic sediment source maps, among which the landslide inventory is of highest importance. Preliminarily, base activities entailed i) the analysis of old and recent geological and topographic maps as well as technical reports on past landslides, ii) field surveys, and iii) the collection of witnesses to particular landslide events. The collected data were then analyzed in combination with wide-area airborne LIDAR (Light Detection and Ranging) and displacement measurements by means of satellite multipass Synthetic Aperture Radar Differential Interferometry (DInSAR), which was applied for the first time in this region for such a purpose. Preliminary landslide susceptibility analyses were also carried out in GIS environment. The followed approach proved to be satisfactory for a feasibility study level when base and thematic maps are incomplete or lacking. The obtained results allowed i) gathering an overview of the unstable conditions affecting the slopes of Polog Region and ii) detecting the most landslide-prone areas, wherein more detailed studies should be addressed in the following stages of the project

Vibrational spectra of (MMIII)-M-I S-2 type synthetic minerals (M-I = Tl or Ag and M-III = As or Sb)

The far infrared and Raman spectra of four (MMS2)-M-I-S-III type synthetic minerals (lorandite, TIAsS2; smithite, AgAsS2; weissbergite, TlSbS2, and miargyrite, AgSbS2) were studied at room temperature. Their vibrational spectra were compared with the corresponding far infrared and Raman spectra Of (M2S3)-S-III type minerals: orpiment, As2S3 and stibnite, Sb2S3. In spite of different crystal structure of these minerals, a similarity between the vibrational spectra of the three arsenic containing minerals (orpiment, As2S3; lorandite, TlAsS2 and smithite, AgAsS2), on the one hand, and the three antimony containing minerals (stibnite, Sb2S3; weissbergite, TlSbS2 and miargyrite, AgSbS2), on the other hand, has been detected. The observed spectral behavior was discussed in terms of structural similarities and differences between the minerals containing As atoms and the ones containing Sb atoms. Thus, the arsenic containing minerals are characterized by the layer-like structure and the presence of rather similar As-S bond distances (208-236 pm), whereas the antimony containing minerals have sheet-like structure and the variety of Sb-S bond distances, spreading in a wider range of values (241-296 pm). (C) 2003 Elsevier Science B.V. All rights reserved

Vibrational spectra of (M3MS3)-M-I-S-III type synthetic minerals (M-I = Tl or Ag and M-III = As or Sb)

The vibrational (Raman and far infrared) spectra of four (M3MS3)-M-I-S-III type synthetic minerals (proustite, Ag3AsS3; ellisite, Tl3AsS3; pyrargyrite, Ag3SbS3; stibioellisite, Tl3SbS3) in the region from 600 to 100 cm(-1) (Raman) and 600 to 20cm(-1) (far infrared) were investigated. Their infrared and Raman spectra were compared with corresponding vibrational spectra of natural orpiment, As2S3, and stibnite, Sb2S3. In general, rather expressed similarity between the Raman spectra of the (M3AsS3)-As-I type synthetic minerals, and particularly between the (M3SbS3)-Sb-I type synthetic minerals (M-I = Ag or Tl) was observed. This is, most probably, due to the presence of the (MS3)-S-III pyramids (M-III = As or Sb) as main structural units in all minerals. The observed similarity between the Raman spectra of the (M3AsS3)-As-I type minerals and the corresponding spectrum of orpiment, As2S3 (also built up of (MS3)-S-III pyramids), justifies the treatment of those pyramids as a main vibrational units. The agreement between the Raman spectra of (M3SbS3)-Sb-I type minerals, on the one hand, and the Raman spectrum of stibnite, Sb2S3, on the other hand, is even much more pronounced. It was found, however, that the bands in the infrared spectra in the studied (M3MS3)-M-I-S-III type minerals, besides the sensitivity to the M-III atom (As or Sb), are significantly influenced by the nature of the M-I atom (Ag or Tl). This is most probably related to the different extent of the covalent character of the Ag-S bonds compared to the Tl-S bonds. (C) 2003 Published by Elsevier B.V