The historical and plastic dimensions of Arabic calligraphy

DOI: 10.7176/ADS/105-05 Publication date:June 30th  2023 ملخص: يتناول هذا البحث الخط العربي بأبعاده التاريخية و مراحل تطوره و تحوله من أسلوب عادي للكتابة اليومية الى الكتابة الجميلة ، من خلال رصد مراحل تطوره و الفترات الزمنية المفصلية في تلك المراحل ، كما يتناول البحث الأبعاد التشكيلية و كيف تم الالتفات الى الخط العربي وتوظيفه في الأعمال التشكيلية من محيط العربي الى خليجه. في محاولة منهم للجمع بين الأصالة و المعاصرة. يتسائل البحث عن مبررات التشكيليين لتضمين و توظيف الخط العربي و العلامة الخطية في أعمالهم، و يستعرض بعض اختلافات الرؤى و الأساليب.

Identification of low oxygen-tolerating bacteria in prostate secretions of cancer patients and discussion of possible aetiological significance

MW was in receipt of Barts and The London Charity Equipment Grant for provision of MOLDI-TOF (Grant reference number 486/1193)

Genotype – environment interaction study in sugar beet (Beta vulgaris L.)

The research was carried out to study the response of 16 cultivars of sugar beet in 3 seasons at one major sugar beet producing location, Hama, in Syria in autumn time, and assess genotype by environment interaction, and to estimate the stability of the varieties performance, according to the yield stability statistics (Ysi), for the studied traits of these varieties. A randomized complete block design with four replications was used. Data collected from each experiment were subjected to simple analysis of variance and after homogenization of error variance, combined analysis for four traits including Sucrose content (SC %), Purity (P %), Root yield (RY ton.ha-1), and Sugar yield (SY ton.ha-1) were carried out. Combined analysis of variance over years, exhibited significant differences (P≤0.05) among the varieties. Results of yield stability statistics (Ysi) revealed that five of the monogerm sugar beet varieties (Vico, Dita, Al Ceste, Chimene, and SR305) were stable for all of the studied traits, during three seasons, which is recommended to be planted in autumn time.International Journal of Environment Vol.5(3) 2016, pp.74-86</p

Seasonal dynamics of microbial sulfate reduction in temperate intertidal surface sediments: controls by temperature and organic matter

The role of microbial sulfate reduction on organic matter oxidation was studied quantitatively in temperate intertidal surface sediments of the German Wadden Sea (southern North Sea) on a seasonal base in the years 1998–2007. The sampling sites represent the range of sediments found in the back-barrier tidal area of Spiekeroog Island: sands, mixed and muddy flats. The correspondingly different contents in organic matter, metals, and porosities lead to significant differences in the activity of sulfate-reducing bacteria with volumetric sulfate reduction rates (SRR) in the top 15 cm of up to 1.4 μmol cm−3 day−1. Depth-integrated areal SRR ranged between 0.9 and 106 mmol m−2 day−1, with the highest values found in the mudflat sediments and lower rates measured in sands at the same time, demonstrating the impact of both temperature and organic matter load. According to a modeling approach for a 154-km2 large tidal area, about 39, 122, and 285 tons of sulfate are reduced per day, during winter, spring/autumn, and summer, respectively. Hence, the importance of areal benthic organic matter mineralization by microbial sulfate reduction increases during spring/autumn and summer by factors of about 2 and 7, respectively, when compared to winter time. The combined results correspond to an estimated benthic organic carbon mineralization rate via sulfate reduction of 78 g C m−2 year−1

Methane and organic matter as sources for excess carbon dioxide in intertidal surface sands: Biogeochemical and stable isotope evidence

The tidal areas of the German Wadden Sea form an important transition zone between the terrestrial and marine environment. Tidal areas represent highly productive marine coastal ecosystems that are under additional influence of riverine inputs. The re-mineralization of organic matter is coupled to reductive processes using oxygen, nitrate, Mn,Fe oxy(hydroxi)des and sulfate as final electron acceptors. Sulfate reduction is involved in the oxidation of DOC and methane, and is the most important anaerobic process leading to a re-flux of CO2 into the water column. CH4 and CO2 are important greenhouse gases. Both are produced in marine sediments but methane fluxes from marine sediments to the water column or the atmosphere are often limited by oxidation. Upon oxidation of organic matter and methane, carbon dioxide is added to pore waters, and both, carbon dioxide and methane may be liberated from intertidal surface sediments into the bottom waters or the atmosphere. Sizes and quality of OM pools and methane concentrations, transport properties as well as biogeochemical processs in intertidal sediments differ in different sediment types (sands, mixed and mud flats). Pore waters and surface sediments from the intertidal of the German Wadden Sea, North Sea, have been analyzed on a seasonal base for a number of (bio)geochemical parameters as, for instance, the contents and isotope composition of TOC, DIC, methane, sulphate reduction rates (SRR), sulfate, sulfide, pyrite, AVS. The typical sediments of the tidal area of Spiekeroog Island have been considered, as sands, mixed and mud flats. The C-13/C-12 partitioning was used to identify the major sources of DIC and key reactions in the coupled C-S cycles. SRR showed a control by season (temperature) and organic matter contents. Bulk organic matter in the surface sediments showed stable carbon isotope data between about -19 and -25 per mil with lighter data found in mixed and mud flats, indicating mixtures between marine and terrestrial organic matter. (Biogenic) methane in hypersulfidic surface sands contained isotope signatures down to -65 per mil. Below reduced sandy surfaces, the isotopic composition of enhanced DIC down to -36 per mil indicate methane as a major source for the oxidized carbon pool. In contrast, DIC was less enriched in the lighter isotope below oxidized surface sands or mixed flats where oxidation of organic matter using oxygen and sulfate as electron acceptors dominated. At Sylt Island the effect of bioturbation and bioirrigation by dwelling organisms (lugworms Arenicola marina) on experimental field sites, was considered, too. In the top 10 cmbsf, highest SRR, DIC concentrations, and lightest C-13 signatures in DIC were observed during summer time with no contribution from CH4

Community structure and activity of a highly dynamic and nutrient-limited hypersaline microbial mat in Um Alhool Sabkha, Qatar.

The Um Alhool area in Qatar is a dynamic evaporative ecosystem that receives seawater from below as it is surrounded by sand dunes. We investigated the chemical composition, the microbial activity and biodiversity of the four main layers (L1-L4) in the photosynthetic mats. Chlorophyll a (Chl a) concentration and distribution (measured by HPLC and hyperspectral imaging, respectively), the phycocyanin distribution (scanned with hyperspectral imaging), oxygenic photosynthesis (determined by microsensor), and the abundance of photosynthetic microorganisms (from 16S and 18S rRNA sequencing) decreased with depth in the euphotic layer (L1). Incident irradiance exponentially attenuated in the same zone reaching 1% at 1.7-mm depth. Proteobacteria dominated all layers of the mat (24%-42% of the identified bacteria). Anoxygenic photosynthetic bacteria (dominated by Chloroflexus) were most abundant in the third red layer of the mat (L3), evidenced by the spectral signature of Bacteriochlorophyll as well as by sequencing. The deep, black layer (L4) was dominated by sulfate reducing bacteria belonging to the Deltaproteobacteria, which were responsible for high sulfate reduction rates (measured using 35S tracer). Members of Halobacteria were the dominant Archaea in all layers of the mat (92%-97%), whereas Nematodes were the main Eukaryotes (up to 87%). Primary productivity rates of Um Alhool mat were similar to those of other hypersaline microbial mats. However, sulfate reduction rates were relatively low, indicating that oxygenic respiration contributes more to organic material degradation than sulfate reduction, because of bioturbation. Although Um Alhool hypersaline mat is a nutrient-limited ecosystem, it is interestingly dynamic and phylogenetically highly diverse. All its components work in a highly efficient and synchronized way to compensate for the lack of nutrient supply provided during regular inundation periods

Effect of sulfate on low-temperature anaerobic digestion

The effect of sulfate addition on the stability of, and microbial community behavior in, low-temperature anaerobic expanded granular sludge bed-based bioreactors was investigated at 15 degrees C. Efficient bioreactor performance was observed, with chemical oxygen demand (COD) removal efficiencies of >90%, and a mean SO42- removal rate of 98.3%. In situ methanogensis appeared unaffected at a COD: SO42- influent ratio of 8:1, and subsequently of 3:1, and was impacted marginally only when the COD: SO42- ratio was 1:2. Specific methanogenic activity assays indicated a complex set of interactions between sulfate-reducing bacteria (SRB), methanogens and homoacetogenic bacteria. SO42- addition resulted in predominantly acetoclastic, rather than hydrogenotrophic, methanogenesis until >600 days of SO42--influenced bioreactor operation. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes. Fluorescence in situ hybridizations (FISH), qPCR and microsensor analysis were combined to investigate the distribution of microbial groups, and particularly SRB and methanogens, along the structure of granular biofilms. qPCR data indicated that sulfidogenic genes were present in methanogenic and sulfidogenic biofilms, indicating the potential for sulfate reduction even in bioreactors not exposed to SO42-. Although the architecture of methanogenic and sulfidogenic granules was similar, indicating the presence of SRB even in methanogenic systems, FISH with rRNA targets found that the SRB were more abundant in the sulfidogenic biofilms. Methanosaeta species were the predominant, keystone members of the archaeal community, with the complete absence of the Methanosarcina species in the experimental bioreactor by trial conclusion. Microsensor data suggested the ordered distribution of sulfate reduction and sulfide accumulation, even in methanogenic granules.Pádhraig Madden was supported by a scholarship from the Irish Research Council. Gavin Collins is supported by a European Research Council (ERC) Starting Grant (‘3C-BIOTECH’; project no. 261330). Profs. Michael Böttcher and Tim Ferdelman, and Dr. Raeid Abed, are thanked for their insightful conversations.peer-reviewe