Lead and Cadmium Concentrations in Throughfall of Pinus eldarica and Cupressus arizonica Plantations in a Semi-Arid Polluted Area

This research was carried out in order to quantify throughfall (TF) and interception loss (I) and to compare the chemical composition of TF, i.e. lead (Pb) and cadmium (Cd) as well as electrical conductivity (EC) and pH beneath Pinus eldarica and Cupressus arizonica plantations and the open field rainfall. The research was accomplished in the Chitgar Forest Park, a semi-arid polluted urban area, around Tehran, Iran. Gross rainfall (GR) was measured using ten collectors located in an open field. TF was quantified by randomly manual TF collectors placed beneath each plantation. Measurements were recorded on an event basis from 15 April 2010 to 15 February 2011. During the measurement, eighteen rainfall events with cumulative GR value of 114.8 mm were recorded. Interception loss was 35.3 mm by P. eldarica plantation and 30.4 mm by C. arizonica. There were strong correlations between I:GR and GR ((r2 Pinus = 0.686, r2 Cupressus = 0.766, p value ≤ 0.01). Pb and Cd concentrations as well as EC of TF were significantly different among P. eldarica and C. arizonica and the open field. The results demonstrated that interception represents a considerable portion of GR in P.eldarica and C. arizonica plantations and, therefore, it should be considered while choosing trees for plantations in semiarid climate zones of Iran. Our results showed that P.eldarica and C. arizonica plantations have good potentials for filtering the polluted air with Pb and Cd

Analysis and correction of noise on electronic circuits in an accelerator environment

Accelerator noise sources can cause both analog and digital electronic circuits to malfunction. This paper identifies and analyzes noise sources, and describes the methodology for measurement. Both general remedies and specific solutions to minimize the noise effects on accelerator electronic circuits are described. A policy for electronic design, board layout, assembly, and fabrication is established. Conclusions are drawn based on theoretical principles with practical examples shown in case studies

A high-current, high-voltage power supply with special output current waveform for APS injector synchrotron dipole magnets

This paper describes a high-voltage, high-current power supply for the injector synchrotron dipole magnets at APS. In order to reset the dipole magnets in each cycle two different current waveforms are suggested. The first current waveform consists of three sections, namely: dc-reset, linear ramp, and recovery sections where injection is done ``on the fly``. The second current waveform consists of six different sections, dc-reset, transition to injection level, injection flat level, parabolic, linear ramp and recovery sections. The effect of such waveforms on the beam is discussed and the power supply limitations to follow such waveforms are given. The power supply limitations are due to the power components and control loops. The reference for the current loop is generated by a DAC which is discussed

Complex systems and the technology of variability analysis

Characteristic patterns of variation over time, namely rhythms, represent a defining feature of complex systems, one that is synonymous with life. Despite the intrinsic dynamic, interdependent and nonlinear relationships of their parts, complex biological systems exhibit robust systemic stability. Applied to critical care, it is the systemic properties of the host response to a physiological insult that manifest as health or illness and determine outcome in our patients. Variability analysis provides a novel technology with which to evaluate the overall properties of a complex system. This review highlights the means by which we scientifically measure variation, including analyses of overall variation (time domain analysis, frequency distribution, spectral power), frequency contribution (spectral analysis), scale invariant (fractal) behaviour (detrended fluctuation and power law analysis) and regularity (approximate and multiscale entropy). Each technique is presented with a definition, interpretation, clinical application, advantages, limitations and summary of its calculation. The ubiquitous association between altered variability and illness is highlighted, followed by an analysis of how variability analysis may significantly improve prognostication of severity of illness and guide therapeutic intervention in critically ill patients

Effects of silvicultural thinning on stand structure and coarse woody debris in the deciduous Arasbaran forest, Iran

Forest stand structure is influenced by artificial factors such as silvicultural activities, and by natural factors such as wildfires, floods, windstorms, diseases, and insect infestations. The silvicultural treatments used during the transformation of coppice to the coppice-with-standard system are a main source of coarse woody debris (CWD). Even small changes in the amounts and/or types of CWD can threaten forest biodiversity, including plant and bird diversity. In this study, we compared managed and unmanaged forest stands in Northwest Iran to better understand changes in species composition and stand characteristics (with particular reference to CWD) in relation to silvicultural practices. In total, thirty-six 0.5-hectare sampling plots were surveyed (total area: 18 ha). We found significant differences between the cut (active management) and uncut areas (proforestation) in indices of height, number of tree species, canopy cover of live and fallen trees, dead tree density, and relative frequency of dead trees. The sample plots included 22 species of live trees, and the CWD was generated by 16 of these species. The number of stems of live trees in the sample plots was 2.653 (SE = 181), with Carpinus orientalis accounting for the highest mean density of live trees. C. orientalis also provided the highest total frequency of downed logs (70%) in the stands, followed by Quercus macranthera (20%). Q. macranthera accounted for the highest relative frequency of dead trees in the stands. In total, around 42% of the CWD consisted of logs lying on the forest floor, followed by dead trees (39%) and stumps (19%). Most of the CWD was included in decay class (DC) 2 (71.6%), followed by DC1 (16.7%) and DC3 (11.3%). Forest managers must balance the amount of CWD, especially from dead trees, in these stands to conserve the diversity of the material in terms of both decay class and tree species

A high-current, high-voltage power supply with special output current waveform for APS injector synchrotron dipole magnets

This paper describes a high-voltage, high-current power supply for the injector synchrotron dipole magnets at APS. In order to reset the dipole magnets in each cycle two different current waveforms are suggested. The first current waveform consists of three sections, namely: dc-reset, linear ramp, and recovery sections where injection is done on the fly''. The second current waveform consists of six different sections, dc-reset, transition to injection level, injection flat level, parabolic, linear ramp and recovery sections. The effect of such waveforms on the beam is discussed and the power supply limitations to follow such waveforms are given. The power supply limitations are due to the power components and control loops. The reference for the current loop is generated by a DAC which is discussed