58 research outputs found
Trace Metals in Surface Sediments of St. Clair River and Lake St. Clair, Michigan
St. Clair River and Lake St. Clair form the waterway connecting channel from Lake
Huron to the Detroit River then drains into Lake Erie. They provide water supply for millions of
people, and critical habitat for maintaining biodiversity in the aquatic environment. Previous
studies reported that the contamination level in St. Clair River and Lake St. Clair sediments
exceeded the allowable limits, and designated the connecting channels as Areas of Concern.
Therefore, the aim of this study was to evaluate the trace metal concentrations (Ag, As, Ba, Cd,
Cr, Cu, Fe, Mn, Hg, Ni, Pb, Se, and Zn) and physico-chemical properties (grain size, total solids,
specific gravity, density, COD, volatile solids, and TOC) in the sediments of St. Clair River and
Lake St. Clair. Sediments were collected from seven sampling locations of St. Clair River in
2009 and nineteen sampling locations of Lake St. Clair in 2010. To characterize the seasonal
variation of the metabolic activities of heterotrophic microorganisms in the sediments, additional
samples were collected from six locations of St. Clair River and Lake St. Clair in spring,
summer, fall and winter of 2015. The analytical results indicated that the metal concentrations
were unevenly distributed on the river and lake bottoms. The metal concentrations of St. Clair
River sediments were lower than Lake St. Clair sediments, due to the fact that rivers such as St.
Clair River, are lotic ecosystems and characterized by rapidly moving freshwater. Therefore,
rivers do not accumulate much of the metals in the sediments but transport the metals to lakes
where the metals concentrate. Nonetheless, the metal concentrations in sediment of the study
were below the allowable regulatory limits. Comparison of metal concentrations of this study
with other connecting lakes and rivers led to the conclusion that the Clinton River and Rouge
River appears to be the source of contamination, and the anthropogenic factors dominated the
process regulating the metal distributions within the study area. The Biolog Ecoplate assay
showed that differences in heterotrophic growth and metabolic diversity between the two
ecosystems were slightly significant, but the differences were more significant between sites
within each ecosystem. This is likely a result of differences in sediment texture between
locations and seasonal changes.Master of ScienceEnvironmental Science, College of Arts, Sciences, and LettersUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/136198/1/Trace Metals in Surface Sediments of St. Clair River and Lake St. Clair, Michigan-Final.pdfDescription of Trace Metals in Surface Sediments of St. Clair River and Lake St. Clair, Michigan-Final.pdf : Thesi
A Comprehensive Analysis of Groundwater Inundation Vulnerability and Remediation for Infrastructures
The rising threat of groundwater inundation, characterized by the elevation of the water table above the ground surface, is increasingly impacting various infrastructure components. This issue has the potential to damage critical infrastructure elements such as building foundations, roads, bridges, and other essential aspects. The intensification of this problem can be linked to the growing frequency of severe weather events, alterations in land use, and increased groundwater withdrawals. This comprehensive review paper seeks to capture the current knowledge base concerning groundwater inundation vulnerability and potential remediation strategies for infrastructure. To achieve this, we performed a thorough literature review encompassing a variety of sources, including peer-reviewed journals, conference proceedings, and technical reports, among others. Our goal is to consolidate the existing understanding of groundwater inundation and its implications for infrastructures and assess the current methodologies for vulnerability evaluation and damage mitigation. Our findings from this review are intended to provide insight into the present state of this field and highlight the significant challenges and promising opportunities for future research
Observations on the Pearl Oyster Fishery of Kuwait
The pearl oyster fishery of Kuwait was monitored daily from January 1989 to May 1990. Landings of pearl oysters in 1989 totaled 287 tons with a market value of U.S. $1.0 million. Commercial pearls (\u3e3 mm) were estimated to be present in one of every 4200 oysters. Most of the pearl oysters landed were new recruits with hinge lengths between 40-56 mm. There was a curvilinear relationship between total weight and size of oysters (length) and the sex ratio approached 1:1. Spawning occurs throughout the year, with a spat settlement peak in early fall. Over the size range examined there was no relationship between the size of oysters and the size of pearls and subsequent resource management strategies are discussed
The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon
We investigated the influence of seagrass canopies on the benthic biodiversity of bacteria and macroinvertebrates in a Red Sea tropical lagoon. Changes in abundance, number of taxa and assemblage structure were analyzed in response to seagrass densities (low, SLD; high, SHD; seagrasses with algae, SA), and compared with unvegetated sediments. Biological and environmental variables were examined in these four habitats (hereafter called treatments), both in the underlaying sediments and overlaying waters, at three randomly picked locations in March 2017. Differences between treatments were more apparent in the benthic habitat than in the overlaying waters. The presence of vegetation (more than its cover) and changes in sedimentary features (grain size and metals) at local scales influenced the observed biological patterns, particularly for macroinvertebrates. Of note, the highest percentage of exclusive macroinvertebrate taxa (18% of the gamma diversity) was observed in the SHD treatment peaking in the SA for bacteria. Benthic macroinvertebrates and bacteria shared a generally low number of taxa across treatments and locations; approximately, 25% of the gamma diversity was shared among all treatments and locations for macrofauna, dropping to 11% for bacteria. Given the low overlap in the species distribution across the lagoon, sustaining the connectivity among heterogeneous soft sediment habitats appears to be essential for maintaining regional biodiversity. This study addresses a current scientific gap related to the relative contributions of vegetated and unvegetated habitats to biodiversity in tropical regions.Peer reviewe
Adsorption of fluoride on a green adsorbent derived from wastepaper: Kinetic, isotherm and characterisation study
The excessive concentration of fluoride (Fâ) in water represents a grave problem for several countries, especially those that depend on groundwater as a main source of drinking water. Therefore, many treatment methods, such as chemical precipitation and membrane, were practised to remove Fâ from water. However, the traditional methods suffer from many limitations, such as the high cost and the slowness. Hence, many studies have been directed towards developing novel and effective water defluoridation methods. In this context, the current study investigates the development of an eco-friendly adsorbent by extracting Ca, Al, and Fe from industrial by-products, precipitating them on sand particles, and using this new adsorbent to remove Fâ from water. The removal experiments were commenced under different pH levels (3-10), contact times (0â240 minutes) and concentrations of Fâ (7.5â37.5 mg/L). X-ray fluorescence (XRF), X-ray diffraction Investigator (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) methods were used to characterise the green adsorbent. Adsorption isotherm and kinetic studies were also conducted to define the adsorption type. The results confirmed that the new adsorbent could remove as high as 86% of Fâ at pH, contact time, agitation speed and adsorbent dose of 10, 180 minutes, 200 rpm and 15 mg/L, respectively. The characterisation studies prove the occurrence of the sorption process and the suitability of the morphology of the adsorbent for Fâ removal. Adsorption kinetics follow better with a pseudo-first-order model that indicates the predominance of physisorption, which agrees with the FTIR results. The isotherm study indicated that Langmuir isotherm is more suitable for representing data with an R2 value of 0.992, which means the adsorption of Fâ occurs as monolayer adsorption on homogeneous sites on the surface of the new adsorbent. In summary, it can be concluded that the developed adsorbent in this study could be a promising alternative to the traditional Fâ removal methods
Species replacement dominates megabenthos beta diversity in a remote seamount setting
Seamounts are proposed to be hotspots of deep-sea biodiversity, a pattern potentially arising from increased productivity in a heterogeneous landscape leading to either high species co-existence or species turnover (beta diversity). However, studies on individual seamounts remain rare, hindering our understanding of the underlying causes of local changes in beta diversity. Here, we investigated processes behind beta diversity using ROV video, coupled with oceanographic and quantitative terrain parameters, over a depth gradient in Annan Seamount, Equatorial Atlantic. By applying recently developed beta diversity analyses, we identified ecologically unique sites and distinguished between two beta diversity processes: species replacement and changes in species richness. The total beta diversity was high with an index of 0.92 out of 1 and was dominated by species replacement (68%). Species replacement was affected by depth-related variables, including temperature and water mass in addition to the aspect and local elevation of the seabed. In contrast, changes in species richness component were affected only by the water mass. Water mass, along with substrate also affected differences in species abundance. This study identified, for the first time on seamount megabenthos, the different beta diversity components and drivers, which can contribute towards understanding and protecting regional deep-sea biodiversity
Effect of Different Extrusion Treatments and Particle Size Distribution on the Physicochemical Properties of Rice Flour
Concept based retrieval and information filtering
Information filtering has become an important component of modern information systems due to significant increase in its applications. The major goals of a successful Information Filtering System include: to close the representation gap between documents and user profiles, and to classify/categorize documents efficiently as they arrive into the system. In this thesis, we develop a conceptual query model that is close to the user\u27s need and investigate an information filtering method for text categorization/classification. The central idea of our conceptual model is captured in a rule based query model. The proposed approach involves preprocessing of the rule base to generate Minimal Term Sets (MTSs) that speed up the retrieval process. Furthermore, we extend our model into two directions when document terms are non-binary. First, we incorporate the p-Norm model into the process of evaluating MTSs. Second, we adopt the Generalized Vector Space model (GVSM) in which the term-term association is well established. For text classification/categorization, we investigate a steepest descent induction algorithm combined with a two-level preference relation on user ranking. The performance of the proposed algorithm is evaluated experimentally. The experiments are conducted using Reuters-21578 data collection. Finally, we demonstrate effectiveness of proposed method by comparing experimental results to other inductive methods
Body mass index, dietary intake and feeding problems of Turkish children with autism spectrum disorder (ASD)
Due to copyright restrictions, the access to the full text of this article is only available via subscription.The body mass index of 164 children (aged 4â18 years) attending four autism rehabilitation centers in Istanbul, Turkey, was determined and assessed using the BMI-for-age percentile charts by the World Health Organization (WHO). The mean intake of energy and nutrients of 115 children were calculated using three-day food records. The feeding assessment surveys filled in by the parents/caregivers indicated that the major feeding problem among children was food selectivity. The majority of the children were overweight or obese (58.5%). A total of 11% of children were found to be severely thin and thin. The calcium, zinc, vitamin B6 and folate intake of the majority of children were inadequate. The salt consumption in all age groups and cholesterol intake in normal, overweight and obese children were high
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