Bacterioplankton dynamics in the Southern Benguela upwelling region

The role of heterotrophic bacteria in the carbon and nitrogen flux of the pelagic food web was investigated during laboratory and field-based studies of the temporal development of the planktonic community after upwelling. Bacterial community structure, activity and production were closely coupled to the upwelling cycle and to the dynamics of the phytoplankton community. The initial bacterial population (<l x 10⁶ cells ml⁻¹, 20 to 40 μg C l⁻¹) was metabolically dormant. Increased availability of phytosynthetically produced dissolved organic carbon (PDOC) stimulated bacterial growth (0.016 h⁻¹) and abundance (8 to 10 x 10⁶ cells ml⁻¹, 140 to 200 μg C l⁻¹). Rapid successions in the dominant plateable strains were attributed to substrate preferences and substrate availability. Significant correlations of bacterial biomass with total standing stocks of phytoplankton and particulate carbon provided evidence of close coupling between bacteria and PDOC, and between bacteria and recalcitrant substrates available during phytoplankton decay. These relationships were best described by power functions, suggesting that bacterial biomass was relatively reduced at high levels by predation. A microcosm study indicated that zooflagellate predation could control bacterial biomass. Low net growth yields (34 to 36%) of flagellates suggested inefficient transfer of carbon to higher trophic levels, but considerable nitrogen regeneration (ca 6 to 7 μg N mg dry weight⁻¹ h⁻¹). Thymidine-measured bacterial production (TTI, <0.1 to 1.25 mg C m⁻³ h⁻¹) was linearly related to phytoplankton growth. Non-uniform response of bacteria to added tracer substrates may result in underestimates of bacterial production by 2 to 34 times by TTI, particularly in deep or oligotrophic waters, or during phytoplankton decay. Close coupling of copepod (Calanoides carinatus) production to the upwelling cycle suggested co-existence of the microbial food web and the classical diatom-copepod food chain. Recently upwelled water was dominated by phytoplankton. Assuming that all phytoplankton carbon was available for utilisation, copepods and bacteria were calculated to consume approximately 12 and 22% of primary production respectively. As the bloom declined the planktonic community was increasingly dominated by bacteria, detritus and mesozooplankton. On average, copepods consumed 60% of primary production, while bacteria consumed 49%. Carbon consumption requirements of both bacteria and copepods were satisfied by resource partitioning and carbon cycling. Under food-limiting conditions herbivorous copepods may switch to omnivory, ingesting microzooplankton of the microbial food web, and stimulating enhanced remineralisation to further sustain primary production. A generic size-based simulation model of the dynamics of the plankton community indicated that bacteria and the microbial food web increase the overall productivity of the planktonic food web, and that heterotroph predation in the smaller size classes (<200 μm) is an important mechanism in nutrient recycling

Forecasts of recruitment in South African anchovy from sarp field data using a simple deterministic expert system

A rule-based deterministic model is used to forecast recruitment of anchovy Engraulis capensis in the southern Benguela from field measurements of biological and environmental variables collected during two consecutive years. Field data were obtained on a monthly basis during the anchovy spawning season as part of the South African Sardine and Anchovy Recruitment Programme (SARP). A total of six indicator variableswas considered for the analysis: distance offshore of the 16°C isotherm; southerly wind stress; anchovy egg abundance; incidence of oocyte atresia in adult females; an index of fish starvation; and oil : meal ratios obtained from commercial data (which were used as an index of fish condition). In the model, data for each variable were assessed against a threshold value. “Active” variables were assumed to contribute towards below-average recruitment by being either above or below their threshold values, as defiNed by the rules. The model was not based on the SARP field data, which were used to test the model. Predicted results from the expert system compared favourably with final estimates of recruitment strength for both 1994 and 1995 (years of below average recruitment), indicating that field measurements of biological and environmental variables may be used in a structured manner to obtain forecasts of anchovy recruitment to the fishery

Invoice, Warschaw Painting Co.- Mr.Jacob Goodman

Bill: Itemized invoice for house repair and painting from Warschaw Painting Co., Inc., Dr. Painters, Decorators and General Contractors, New York, New York. Date December 29, 192

Risk management:the effect of FIST on perceived safety in crowded large space buildings

Facilities management within large space buildings used by large crowds must involve effective risk management as a key component. Poor risk management within large space buildings such as sports stadiums, concert halls, and religious buildings have resulted in crowd disasters in various venues across the world. Fruin suggested that Force, Information, Space and Time (FIST) are the main factors that influence the occurrence of crowd disaster. Within the built environment, safety is considered in two main parts: objective safety (normative and substantive) and subjective safety (perceived). This paper theorised that poor perceived safety alone could result in crowd disaster, and by using the FIST model, it investigates the relationship between the four critical FIST factors and perceived safety in crowded large space buildings. The research chose to use the Holy Mosque in Makkah as a case study, a building where large crowd always use on a continuous basis all year round with its peak occupancy usually reached during the Hajj (an annual pilgrimage to Makkah that is undertaken by Muslims from all over the world). The Holy Mosque is a large building of 356,800 square metres with a maximum capacity of two million users (pilgrims). Data was collected using iPad devices via a group-administered questionnaire distributed to 1940 pilgrims of 62 different nationalities. The results were analysed using SPSS for descriptive analysis and AMOS 22 for Confirmatory Factor Analysis (CFA) and Structural Equation Modelling (SEM). The fitness of the model was tested, and the unidimensionality, convergent validity, discriminant validity, and reliability were assessed. The findings confirmed that there is a significant relationship between the FIST factors and perceived safety in crowded large space buildings. These findings will assist the facilities managers by making them aware of the users’ safety perception and the factors that make them feel unsafe

Seasonal changes in phytoplankton biomass on the Western Agulhas bank, South Africa

Data on temporal and spatial changes in phytoplankton biomass and distribution on the western Agulhas Bank during the main spawning season of pelagic fish were obtained from monthly cruises conducted betweenAugust and March in 1993/94 and September and March in 1994/95. The period was divided into three oceanographic seasons based on different levels of upwelling activity: late winter (August and September), spring(October–December) and summer (January–March). Cross-shelf and vertical distribution patterns of chlorophyll changed markedly during these seasonal periods, reflecting changes in hydrographic structure and in nutrient availability. During late winter, chlorophyll was evenly distributed in the deep, upper-mixed layer (>40 m) across the shelf. A clump-forming Thalassiosira sp. contributed to the moderately high mean chlorophyllconcentration (1.9 mg·m–3) in the upper 30 m. In October and/or September, warming of surface waters inshore gave rise to a modest (2–5 mg chl·m–3) spring bloom, typical of the temperate zone. This was terminated in November by an influx across the shelf of warm, nutrient-impoverished water. Upwelling was sporadic and weak in spring. Summer was characterized by intense, episodic upwelling inshore, with pronounced cross-shelf thermal gradients, intensified by the presence of water of Agulhas origin along the shelf-edge. During an upwelling cycle, rapid hydrographic and biological changes occur over four phases: onset of upwelling, sustained upwelling, quiescence and downwelling. The upwelling productive zone, bounded by the 20°C isotherm, varied fro

Modeling energy savings of glazed and unglazed collectors used for space heating, water heating, and space cooling

Glazed and unglazed solar thermal collectors were compared in TRNSYS simulations for a multi-use application of water heating, space heating, and space cooling. The collectors provided space cooling by radiating heat to the night sky. The overall solar fraction achieved by two (7.6 m2) of the glazed collectors was similar to the solar fraction achieved by six (22.8 m2) of the unglazed collectors in the climates of Raleigh, NC, Jacksonville, FL, and Albuquerque, NM. However, the unglazed collectors produced less energy cost savings at these sizes because a greater proportion of their energy was provided as cooling, which was supplied more efficiently by auxiliary equipment. For each type of collector, the greatest solar fraction of space heating and water heating were achieved in Jacksonville, and the greatest solar fraction of space cooling was achieved in Albuquerque. The climate of Raleigh generally produced heating and cooling performances that were in the middle of the range produced by collectors in the three geographic regions. For glazed and unglazed arrays of equal size in Raleigh (15.2 m2), the ratio of the unglazed solar fraction to the glazed solar fraction was 0.26 for space heating, 0.73 for water heating, and 2.71 for space cooling

Comparisons of students’ perceptions on BIM practice among Australia, China and UK

University students are the future driving forces in and leaders of the architectural, engineering and construction (AEC) industry advancement. Although BIM pedagogical studies have been performed in different institutions, there has not been sufficient research providing a global perspective of BIM education and students’ perceptions toward BIM practice and application following their learning progress. The purpose of this paper is to adopt student samples from Swinburne University of Technology (SUT, Australia), Wenzhou University (WZU, China) and University of Brighton (UK) as three case studies to investigate the BIM practice and application-related perceptions and motivations. Design/methodology/approach Based on the thorough understanding of the BIM pedagogical delivery including teaching contents and assessment methods among the three institutions, a questionnaire survey approach was adopted to collect AEC students’ perceptions of BIM. Within each selected case, statistical analysis was conducted to investigate both the overall sample and subgroup differences regarding students’ opinions on BIM’s functions (e.g. as a 3D visualization tool) and BIM usefulness in various industry professions, their motivation in BIM-related jobs and their perceptions of challenges encountered in BIM practice and application. Multiple factors influencing BIM learners’ perceptions were discussed, such as pedagogical assessment approach, and individual factors (e.g. disciplines). Findings The results showed that students were able to discern the latest industry practices and critical thinking in BIM movements. For example, SUT students perceived more challenges from the government legislation or incentive policies, which was consistent with Australia’s BIM policy movement. WZU students tended to have less positive views on BIM usefulness. The results also indicated fewer differences regarding perceived challenges among students from these three institutions. Originality/value This study contributed to the body of knowledge in managerial BIM by focusing on learners’ perceptions from the perspective of students’ understanding, motivation and individual views of BIM, which were insightful to both BIM educators and employers. By initiating the framework of BIM learning process and its influence factors, the current study serves as a point of reference to continue the future work in strengthening the connection between institutional BIM education and industry practical needs worldwide

Relationships Between Poe's Imagery and His View of the Universe

55 leaves.Poe's images in both his prose and his poetry are closely related to his concept of the universe and man's position in it. The images suggest many of the ideas Poe presents in Eureka. Much of the preparation for this thesis was involved with a careful reading of Poe's work. His critical writing, especially Eureka, was studied in an attempt to make some basic observations about his philosophy. His prose and poetry were then viewed in light of his basic philosophical assumptions. Conclusions were then drawn regarding the appropriateness of Poe's images for his central themes. Secondary sources were consulted either to expand or substantiate some of the arguments of the thesis. Poe describes the universe in terms of repulsion and attraction, forces that work on both the physical and the spiritual dimensions. Repulsion has caused a moving away from unity; consequently, Poe's images reflect the superiority of the past and the inferiority of man's present condition. However, the attractive force sends all in the direction of unity and, therefore, is associated with positive images. In addition, Poe's images suggest man's quest for spiritual understanding and his attempt to reconcile the demands of his body with the demands of his soul