Wind reduction patterns around isolated biomass for wind erosion control in a desertified area of Central Sudan

The aim of this study was to assess the effectiveness of sparse vegetation, feature common in arid zone, to reduce wind force (velocity) and hence protect the surface and regions downwind from drifting sand and their consequences. Respectively 4 (with heights h of 4, 3.2, 2 and 1.66 m), 2 (with h of 3 and 2.5 m) and 3 (with h of 1.04, 0.9 and 0.8 m ) well established single biomass configurations of Leptadenia pyrotechnica trees, Prosopis juliflora trees and Panicum turgidum grass, were selected in the field. Solar powered cup anemometer wind measurements with a data logger system were taken at heights of 0.25 and 0.5 h, at distances 0.5 and 1 h, at four sides of the tree in the prevailing wind direction and perpendicular to it, and additionally at 2, 4 and 6 h windward and leeward. The protection effectiveness of the biomass was calculated as a wind reduction ratio and in terms of objects protection, which was evaluated using the dimensionless protection index (É). The study showed that windward protection provided by Leptadenia and Prosopis at level 0.25h and distance 0.5 h was similar, w ith a wind reduction ratio R0.8, while Panicum showed comparably higher R-values. Even at the 0.5 h level, Panicum showed an R of 0.65 at 0.5 h distance. Leew ard, at 0.25 h level differences were small, R increasing from 0.6/0.7 to 0.8/1 with distance, Leptadenia protecting best. At higher level (0.5 h) at distances 0.5 and 1 h Prosopis gave better protection than the other two at distances 0.5, 1 and 2 h. The research is an exam ple of simple experimental work under difficult environmental conditions in Africa. It was part of studies in which additional attention was paid to quantification aspects under such conditions as well as to the problems it helped solve in the African societies concerned as agrometeorological service

Les "Diary methods" : présentation et cas d'application d'une méthode de collecte de données basée sur la tenue d'un journal personnel

La vie est ponctuée d'événements quotidiens, prenant la forme de décisions, d'engagements, et d'actes, et suscitant des réactions émotionnelles, attitudinales et comportementales. Une analyse de la vie des salariés dans les organisations, basée sur l'étude des événements semble dés lors cruciale pour la compréhension des expériences quotidiennes vécues dans un contexte de travail. Puisque des événements plus ou moins importants se produisent à toute heure dans une journée de travail, la vie des salariés est régulièrement soumise aux aléas que ces expériences engendrent, même si elle donne l'impression d'une certaine stabilité. Ces événements et ces expériences en évolution quotidienne font que notre humeur peut changer d'un jour à l'autre. Les attitudes et les traits de personnalité sont certes importants, cependant leur impact sur nos vies passe inéluctablement par les événements et les expériences quotidiens. Pour exprimer cela plus formellement, nous pouvons dire que la vie est un processus dynamique, changeant et continue, impliquant événements, expériences, réflexions, sentiments et motivations qui varient considérablement dans le temps.gestion des ressources humaines;méthode du journal personnel

A parametric study of fear generalization to faces and non-face objects: relationship to discrimination thresholds

Fear generalization is the production of fear responses to a stimulus that is similar—but not identical—to a threatening stimulus. Although prior studies have found that fear generalization magnitudes are qualitatively related to the degree of perceptual similarity to the threatening stimulus, the precise relationship between these two functions has not been measured systematically. Also, it remains unknown whether fear generalization mechanisms differ for social and non-social information. To examine these questions, we measured perceptual discrimination and fear generalization in the same subjects, using images of human faces and non-face control stimuli (“blobs”) that were perceptually matched to the faces. First, each subject’s ability to discriminate between pairs of faces or blobs was measured. Each subject then underwent a Pavlovian fear conditioning procedure, in which each of the paired conditioned stimuli (CS) were either followed (CS+) or not followed (CS−) by a shock. Skin conductance responses (SCRs) were also measured. Subjects were then presented with the CS+, CS− and five levels of a CS+-to-CS− morph continuum between the paired stimuli, which were identified based on individual discrimination thresholds. Finally, subjects rated the likelihood that each stimulus had been followed by a shock. Subjects showed both autonomic (SCR-based) and conscious (ratings-based) fear responses to morphs that they could not discriminate from the CS+ (generalization). For both faces and non-face objects, fear generalization was not found above discrimination thresholds. However, subjects exhibited greater fear generalization in the shock likelihood ratings compared to the SCRs, particularly for faces. These findings reveal that autonomic threat detection mechanisms in humans are highly sensitive to small perceptual differences between stimuli. Also, the conscious evaluation of threat shows broader generalization than autonomic responses, biased towards labeling a stimulus as threatening

THE USE OF LANDSCAPE ARCHITECTURE TO ENHANCE THE BUILT ENVIRONMENTA STUDY OF THE CITY OF ALEXANDRIA, EGYPT

The landscape architecture profession and its role in the planning process in Egypt are not clear and well defined. This led to the production of plans which lacks the existence of an obvious landscape strategy to both existing and new cities. A landscape planning concept which helps to maximize the contribution of the open spaces to the character and appearance of the city; conserve features and areas of historic interest; conserve and enhance existing features of wildlife interest and where appropriate create new habitats; facilitate public enjoyment and recreation in a way which respects the landscape and minimizes its erosion; to provide a linked network of safe, rich and varied open spaces for us all to enjoy and value throughout the city and to promote links with the surrounding countryside. The overall objective of this paper is to produce a set of guidelines for developing a landscape strategy for the Egyptian cities. This aims to ensure that the city’s landscape is adequately protected and cared for, so that its extent, quality, biological diversity and contribution to the character and appearance of the city can be sustained and enriched for the benefit and enjoyment of the people and visitors. As well as addressing the need to restore a balance within the city\u27s landscape, whereby the natural forces of change are managed, the damaging actions of people are limited and a climate is created to encourage the development of good quality landscape design throughout the city. This will be enhanced by using an analytical approach to focus on the city of Alexandria as an example of the Egyptian statues of landscape architecture, reaching the development of a landscape strategy check list

THE USE OF SMART GEOMTRY IN ISLAMIC PATTERNS A GENERATIVE APPROACH TO THE RESTORATION OF THE ISLAMIC URBAN AREAS

Geometry is an essential design generator in the Islamic architectural style. Islamic styles are distinct for using the art of geometry in their creative designs. In the Islamic designs, geometry represents the order, harmony and beauty in calculations, scale and proportion. It clearly exists in the design of plans, façade, ornaments and patterns. It expresses many concepts of Islam such as the unity and the oneness of Allah, the perfection and the infinity of creation in the universe, the containments and the continuity. The main proportions of the Islamic style depend on the square proportions(ex: Islamic proportion 1:√2 (Williams, 2006), in which the square is the basic module shape that generates the other geometric forms such as the famous Islamic star, octagonal Islamic rose. In addition, square gives the basic axes and symmetry in the main internal spaces such as the Courtyard in the mosques. So far the role of geometry has been fundamentally dependent in which in it contains, regulates and supports the module of the elements. Islamic geometry and proportions are following special shape grammar rules and relations which should be taken into consideration while the design process or the restoration of historical buildings. One can see the Islamic geometry simple in shape but precisely it is composed of a number of complex relations. And when the rules and the relations increase, the complexity in manipulating the geometry manually increases. That requires more time and effort to execute or modify.Therefore, parametric design strategies are employed to aid in solving this complexity.Parametric design develops the geometry to be more related and dependent. Consequently geometry is introduced in a new smart one. In the traditional CAD software’s, if one of the related geometries is deleted or changed, the modeled relationship may be lost. However, Smart geometry, as well as the parametric design, can convert lines, arcs, shapes, solids, and surfaces into a set of algebraic and geometric constraints that could easily generate those patterns according to a specific relations and proportions. Thus, a number of alternatives are presented to use the most suitable solution in a short time

Metabolic Environment and Cellular Signaling in Haematopoietic Stem Cells and Progenitor Cells

This work demonstrates how the nutrient and physico-chemical environment can indeed affect the self-renewal versus differentiation of haematopoietic progenitor cells in vitro, consistent with the proposed existence of metabolic niches in vivo that contribute to the organization and control of haematopoiesis. The identification of Nme2 as a key link between metabolic and signaling activities should enable more detailed analysis of these relationships in the future

IMPACT OF MERGER AND ACQUISITION STRATEGIES ON BUSINESS GROWTH IN QATAR AND GLOBAL MARKETS

Increased globalization and competition in various industries has led to the rise of mergers and acquisitions for companies seeking competitive edge. The objective of this study is to investigate the impact of mergers and acquisitions (M&A) on business growth in Qatar and global markets. The study adopted a quantitative research design approach to understand the post-M&A performance dynamics, examining key variables such as revenue growth and return on investment (ROI). The survey also explores other factors influenced by M&A, like market share, profitability, liquidity, and leverage. The study's population encompassed four Qatar-based companies and three global companies involved in M&A transactions since 2009. The study used secondary data from financial reports as well the regulatory authorities' annual reports of the merged companies before and after merging with competitors. Descriptive statistics compared pre- and post-merger values, offering insights into changes in business performance and operations. Correlation analysis assessed associations between variables before and after mergers, while regression analysis explored their relationship with business growth. Findings indicate M&A boost revenue growth in Qatar-based firms, even though exceptions exist among international corporations. Qatar firms showed no significant ROI improvement post-merger, unlike Verizon Inc. Market share increased for all the companies post-merger, indicating enhanced market dominance. Likewise, profitability ratios decreased for most companies except Verizon Inc. Liquidity ratios also decreased post-merger, except for AT&T Inc., while leverage varied. Correlation analysis revealed positive relationships between market share and growth pre- and post-merger, with ROI showing a weaker premerger negative correlation, shifting to a weaker positive correlation post-merger. Pre-merger regression had limited explanatory power (19.1% variance), contrasting with post-merger (86.3%). None of the variables were statistically significant pre-merger, but post-merger, ROI and leverage showed positive but insignificant relationships with business growth. The findings highlight M&A's varied impact on business growth, emphasizing the importance of integration management and strategic planning for maximizing benefits and driving sustainable growth in Qatar and global markets

The binding and activation of the glucagon-like peptide-1 receptor by exendin-4

Background and purpose Exendin-4 (EX4) has the same physiological properties as glucagon-like peptide-1 (7-36)amide (GLP-1). EX4 has 50% identity with GLP-1, with an extra nine amino acids at its C-terminus. The two peptides mediate their functions through coupling to the glucagon like peptide-1 receptor (GLP-1R) with similar affinity and potency. Unlike N-terminally truncated GLP-1, (GLP-1(15-36)amide), the equivalently truncated EX4(9-39) binds GLP-1R without significant loss of affinity; furthermore, GLP-1(15-36) is a partial agonist while EX4(9-39) is an antagonist. Previous binding analysis of either N or C-terminally truncated EX4 at rGLP-1R suggested that the residues responsible for its extra affinity are at its C-terminus, EX4 residues 31-39. Crystal structures supported by mutagenesis showed similar interactions of both GLP-1 and EX4 at the isolated N-terminal domain of human GLP-1R (hGLP-1R-NTD) apart from a subtle hydrogen bond between Ser32 in EX4 and Glu68 in hGLP-1R-NTD. Experimental approach The affinities and activities of GLP-1, EX4 and various analogues were measured at human and rat GLP-1R (hGLP-1R and rGLP-1R, respectively) and various receptor variants. Computer models, molecular dynamics coupled with in silico mutagenesis, were used to model and interpret the data. Key results The membrane-tethered NTDs of hGLP-1R displayed similar affinity for GLP-1 and EX4 in contrast to previous studies using the soluble isolated domain. The selective high affinity at rGLP-1R and the rGLP-1R-like mutant hGLP-1R-Glu68Asp for EX4(9–39) over EX4(9–30) was due to Ser32 in the ligand. This selectivity was not observed with hGLP-1R and the hGLP-1R-like mutant rGLP-1R-Asp68Glu. Gly16-EX4(9–30) was an agonist for rGLP-1R and hGLP-1R-Glu68Asp but was an antagonist for hGLP-1R and rGLP-1R-Asp68Glu. Glu22-GLP-1(15-36) was a partial agonist for all tested receptors. Insertion of (EEEAVRL) of EX4 instead of their equivalent sequence in GLP-1(15-36) prevented its activity and did not enhance its affinity. Substitution of Ser32 in EX4 by similar hydrogen bond donor amino acids did not enhance EX4 affinity or potency. Conclusions and implications GLP-1 and EX4 bind to the NTD of hGLP-1R with similar affinity. A hydrogen bond between Ser32 of EX4 and Asp68 of rGLP-1R is responsible for the improved affinity of EX4 and can play a role in the antagonist/agonist switch of Gly16-EX4(9–30) at the rat receptor. The discovery of the novel antagonist/agonist switch suggests a new mechanism of activation by GLP-1 which does not require its extreme N-terminal residues.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Fabrication of Tm2O3/Al2O3-silica preform by improved MCVD-chelate delivery system

The fabrication of Tm/Al-doped silica preforms by an improved MCVD method with metal chelate precursors is discussed. Two fabrication techniques are employed, namely; simultaneous soot-dopant deposition (or standard MCVD) and stepwise soot-dopant deposition. The preforms are characterized by refractive index profiler and EPMA. The results show that the stepwise soot-dopant technique has a higher incorporation of Al2O3 and Tm2O3 as compared to the simultaneous soot-dopant method. This is due to the drawbacks of our chelate delivery system such as the temperature gradient and flow design. For the stepwise technique, the measured index difference of the preform is 0.006 with 0.8 wt% (maximum) Tm incorporated in the core