The landscape context of planning for recreation: "the psycho- physiological approach to the design of open spaces"

The demand of modern living with social and economic tensions has created a society characterised by change. This constant change in most aspects of daily life has encouraged an increasing number of people to turn to recreation interests as a means of gaining inner satisfaction, self expression and personal fulfilment. Recreation has become an important component of the urban planning and design for societies.The research is devoted to the study of recreation as a vital component of life. Its importance stems from its maintenance of the physical and mental health for both society and individuals. The lack of satisfactory planning and design for recreation in a society would accordingly lead to slow disintegration

Towards a code of ethics for community psychology and community practice in the Arab world: Defining ethical values

In response to the need for ethical guidance in Arab community psychology and other forms of community practice, this thesis used mixed methods to explore the ethical values that are of relevance to community psychologists and other community practitioners in the Arab World. A total of 18 community practitioners in the Arab region were interviewed to share their views on the importance of Arab societal values, the values of community psychology, and the principles identified in globally dominant codes of ethics for psychologists in community practice in the Arab world. Using thematic analysis, 53 themes were identified in the collected qualitative data, portraying the most important and influential values in Arab community practice. Moreover, 211 community practitioners in the Arab world responded to a self-administered questionnaire on the extent to which certain values are beneficial or problematic for Arab community practice. Descriptive statistics were used to analyze the questionnaire, identifying the most beneficial values, controversial values and values that were sometimes viewed as irrelevant to Arab community practice. Based on the interview and questionnaire data, a list of recommended ethical values for Arab community practice is identified. Since codes of ethics are built on values, the results of this research are the first step towards building a comprehensive and culturally relevant code of ethics for community practitioners, including community psychologists, in the Arab region

Koeficijenti udarne ionizacije elektronom i šupljinom u poluvodičima s jakim poljem

We have fitted the soft lucky drift model of impact ionization of Ridley to experimental data for GaAs, InP, Si, Ge and In0.47Ga0.53As semiconductors. Excellent fits of the theory to experimental data were obtained by using least-squares fitting algorithm. A generalized Keldysh formula has been used to introduce a soft threshold factor. Generalized Keldysh formula originates from realistic energy bands in semiconductors at high electric field which reflects the density of states of energy bands. Keldysh factor and a new mean free path are calculated. A comparison with reported values of both Ridley and Marsland showed reasonable agreement for mean free path, but there are still large differences among Keldysh factors.Načinili smo prilagodbe Ridleyvog mekog sretno-posmičnog modela eksperimentalnim podacima za GaAs, InP, Si, Ge i In0.47Ga0.53As. Postigli smo odlično slaganje teorije i eksperimentalnih podataka primjenom metode najmanjih kvadrata. Primijenili smo poopćenu Keldyshevu formulu radi uvođenja mekog faktora praga. Poopćena Keldysheva formula proizlazi iz realnih razmatranja energijskih vrpci u poluvodičima s jakim električnim poljima što odražava gustoću stanja energijskih vrpci. Izračunali smo Keldyshev faktor i nove vrijednosti srednjih slobodnih puteva. Ridleyeve and Marslandove objavljene vrijednosti za srednje slobodne puteve u dobrom su skladu s našima, ali još uvijek nalazimo velike razlike među Keldyshevim faktorima

Koeficijenti udarne ionizacije elektronom i šupljinom u poluvodičima s jakim poljem

We have fitted the soft lucky drift model of impact ionization of Ridley to experimental data for GaAs, InP, Si, Ge and In0.47Ga0.53As semiconductors. Excellent fits of the theory to experimental data were obtained by using least-squares fitting algorithm. A generalized Keldysh formula has been used to introduce a soft threshold factor. Generalized Keldysh formula originates from realistic energy bands in semiconductors at high electric field which reflects the density of states of energy bands. Keldysh factor and a new mean free path are calculated. A comparison with reported values of both Ridley and Marsland showed reasonable agreement for mean free path, but there are still large differences among Keldysh factors.Načinili smo prilagodbe Ridleyvog mekog sretno-posmičnog modela eksperimentalnim podacima za GaAs, InP, Si, Ge i In0.47Ga0.53As. Postigli smo odlično slaganje teorije i eksperimentalnih podataka primjenom metode najmanjih kvadrata. Primijenili smo poopćenu Keldyshevu formulu radi uvođenja mekog faktora praga. Poopćena Keldysheva formula proizlazi iz realnih razmatranja energijskih vrpci u poluvodičima s jakim električnim poljima što odražava gustoću stanja energijskih vrpci. Izračunali smo Keldyshev faktor i nove vrijednosti srednjih slobodnih puteva. Ridleyeve and Marslandove objavljene vrijednosti za srednje slobodne puteve u dobrom su skladu s našima, ali još uvijek nalazimo velike razlike među Keldyshevim faktorima

Dielectric Function in Highly doped GaN Semiconductor

Inverse of Dielectric Function of highly doped  GaN has been calculated by using Lindhard formalism.  For simplicity collisional damping,  nonparabolicity and the coupling  between various  electrons and holes  were  neglected. The inverse of the dielectric function for both Fermi- Dirac and Maxwell Boltzman distribution showed antiscreening peak at small phonon wave vector. On the contrary, both Thomas Fermi and Debye inverse of dielectric function showed screening as expected at same phonon wave vector. There is a sharp growth in the antiscreening peak in the inverse of dielectric function at carrier temperature 77 K and 300K, accompanied with a singularity at carrier concentration greater than . Key words: dielectric function, GaN and screened optical phonon scattering rat

Seismic hazard studies in Egypt

Abstract The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba–Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5°) within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA) values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA) values were detected in the western part of the western desert and it is less than 25 gal

Spectroscopic and biological activity studies on tridentate Schiff base ligands and their transition metal complexes

Schiff base ligands are prepared via condensation of pyridine-2,6-dicarboxaldehyde with 2-aminothiophenol (H2L1) and 2-aminobenzoic acid (H2L2), respectively. The ligands are characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, and thermal analyses (TG, DTG and DTA). The molar conductance reveals that all the metal chelates are non-electrolytes except Th(IV) H2L2 complex which is 1:1 electrolyte . IR spectra show that H2L1 and H2L2 ligands behave as neutral tridentate ligands and bind to the metal ions via the two azomethine N and pyridine N. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral (Cr(III)- and Fe(III)-H2L1 and H2L2, Th(IV)-H2L2 and Mn(II)-H2L1 complexes) and triagonal bipyramidal (Co(II), Ni(II), Cu(II), Cd(II) and UO2(II)-H2L1 and H2L2 and Mn(II)-H2L2 complexes). The thermal behaviour of these chelates is studied using TG and DTA techniques and the activation thermodynamic parameters are calculated using Coats-Redfern method. The synthesized ligands and their metal complexes were screened for their biological activity against bacterial species (Escherichia coli, P. vulgavis, B. subtilis and S. pyogones) and fungi (F. solani, A. niger and A. liavus). The activity data show that the metal complexes have antibacterial and antifungal activity more than the parent Schiff base ligands against one or more bacterial or fungi species

Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

Copyright © 2016 Yousif et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License Creative Commons Attribution 4.0 International, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.When processing sensory signals, the brain must account for noise, both noise in the stimulus and that arising from within its own neuronal circuitry. Dopamine receptor activation is known to enhance both visual cortical signal-to-noise-ratio (SNR) and visual perceptual performance; however, it is unknown whether these two dopamine-mediated phenomena are linked. To assess this, we used single-pulse transcranial magnetic stimulation (TMS) applied to visual cortical area V5/MT to reduce the SNR focally and thus disrupt visual motion discrimination performance to visual targets located in the same retinotopic space. The hypothesis that dopamine receptor activation enhances perceptual performance by improving cortical SNR predicts that dopamine activation should antagonize TMS disruption of visual perception. We assessed this hypothesis via a double-blinded, placebo-controlled study with the dopamine receptor agonists cabergoline (a D2 agonist) and pergolide (a D1/D2 agonist) administered in separate sessions (separated by 2 weeks) in 12 healthy volunteers in a William's balance-order design. TMS degraded visual motion perception when the evoked phosphene and the visual stimulus overlapped in time and space in the placebo and cabergoline conditions, but not in the pergolide condition. This suggests that dopamine D1 or combined D1 and D2 receptor activation enhances cortical SNR to boost perceptual performance. That local visual cortical excitability was unchanged across drug conditions suggests the involvement of long-range intracortical interactions in this D1 effect. Because increased internal noise (and thus lower SNR) can impair visual perceptual learning, improving visual cortical SNR via D1/D2 agonist therapy may be useful in boosting rehabilitation programs involving visual perceptual training.Peer reviewe