Congener profiles of polychlorinated biphenyls and the effect on marine mussels at an outfall site, Port Elizabeth, South Africa

This study investigated the effect of freshwater as a point source of PCBs contributing to a marine outfall region. Inflowing and outflowing water from the North End Lake, Port Elizabeth, was collected to determine the contamination levels of polychlorinated biphenyls (PCBs). Mussels at the outflow to the sea were also sampled. The samples were analysed by an internal standard method for 6 indicator PCB congeners using gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring (SIM) mode. The total PCB concentrations in the water (dissolved plus particulate phases) ranged from 0.180 to 0.355 ng∙L-1 and from 20.84 to 31.34 ng∙g-1 wet weight (ww) in mussels. Lighter PCB congeners exhibited highest concentrations in the water samples while heavier PCBs were dominant in mussels. PCB-52 was the most abundant in the water samples while PCB-153 was abundant in mussels. To protect human health from the possible effects of eating fish and shellfish contaminated with PCBs, the Environmental Protection Agency regulates that the level of PCBs in water be no greater than 0.17 ng∙L-1 of water. The levels of PCBs in water from the North End Lake were found to be high (0.180 – 0.355 ng∙L-1) compared to the levels recommended by EPA.Keywords: dissolved phase, GC/MS, North End Lake, particulate phase, sedentary organism

The benthic regeneration of N and P in the Great Brak estuary, South Africa

The Great Brak is a temporarily open/closed estuary (TOCE) located on the south coast of South Africa. The construction of the Wolwedans Dam in 1989 reduced baseflow to the estuary by 56%, decreasing the intensity of flushing events and causing the mouth to breach less often. The aim of this study was to  investigate the flux of inorganic nutrients (NH4 +, TOxN [NO3 - + NO2 -], SRP) as well as total N and P across the  sediment–water interface in the estuary. There have been very few studies on nutrient cycling and benthic  pelagic coupling in South African estuaries. This study showed that the sediment had a net efflux of NH4 +, SRP, TN and TP while TOxN was taken up or converted to other forms of N. The estuary acted as a source of N and P during both summer and winter. If the estuary  remains closed for a prolonged period (12 months), with an increased organic load present on the benthos, the associated rates of efflux of N and P would increase. In order to reduce the organic load to the system better flushing methods or, more importantly, an increase in base flow, is needed to reduce residence times of water in the estuary.Keywords: water quality, nutrient cycling, benthic-pelagic coupling, estuar

Use of dietary supplements by cardiologists, dermatologists and orthopedists: report of a survey

<p>Abstract</p> <p>Background</p> <p>Dietary supplements are regularly used by a majority of the American population, and usage by health professionals is also common. There is considerable interest in usage patterns within the population and in the reasons for using dietary supplements. The "Life...supplemented" Healthcare Professionals 2008 Impact Study (HCP Impact Study) surveyed usage of dietary supplements by physicians in three specialties: cardiology, dermatology, and orthopedics.</p> <p>Methods</p> <p>The HCP Impact Study was conducted online by Ipsos Public Affairs for the Council for Responsible Nutrition (CRN), a trade association of the dietary supplement industry. Respondents were 900 physicians, including 300 each from three specialties - cardiology, dermatology, and orthopedics.</p> <p>Results</p> <p>Fifty-seven percent of cardiologists said they use dietary supplements at least occasionally, as did 75% of dermatologists and 73% of orthopedists. The product most commonly reported to be used was a multivitamin, but over 25% in each specialty said they used omega-3 fatty acids and over 20% said they used some botanical supplements. Regular dietary supplement use was reported by 37% of cardiologists, 59% of dermatologists, and 50% of orthopedists. Seventy-two percent of cardiologists, 66% of dermatologists, and 91% of orthopedists reported recommending dietary supplements to their patients. The primary reason given for recommending dietary supplements to patients was for heart health or lowering cholesterol for the cardiologists; benefits for skin, hair and nails for the dermatologists; and bone and joint health for the orthopedists.</p> <p>Conclusions</p> <p>Reported dietary supplement use was relatively common in this sample of physicians, and when they recommended dietary supplements to patients, they tended to do so for reasons related to their specialty.</p

Reinterpreting the development of reading skills

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88027/1/RRQ.40.2.3.pd

A silent cry for leadership : organizing for leading (in) clusters

Leadership research so far has neglected clusters as a particular context for leadership, while research on networks and clusters has hardly studied leadership issues. This paper fills this dual gap in the abundant research on leadership on the one hand and on networks/clusters on the other by investigating leadership in photonics clusters from a structuration perspective. Apart from giving an insight into the variety and patterns of leadership practices observed, the paper addresses the dilemma that regional innovation systems such as clusters usually have a critical need of some kind of leadership, but that neither individual nor organizational actors wish to be led. This dilemma can only be ‘managed’ by organizing for leading (in) clusters in a certain way

A divergence of opinion: how those involved in child and family social work are responding to the challenges of the Internet and social media

This discussion paper suggests that there is possibly a divergence of opinion taking place within the field of child and family social work and that the stated positions are influencing how practitioners identify and deal with risks and opportunities afforded by the Internet and social media. The suggested divergence is examined and the conclusion drawn is that what is taking place mirrors the fact that the introduction of any new technology inevitably brings with it division and debate. In seeking to understand the reaction to digital technology consideration is given to a series of wider social discourses on childhood and risk which includes the controversial notion that the profession is a harbinger of moral panic and that the management of risk has been broadened from child protection to child safety. The discussion paper concludes by calling for child and family social work practitioners to have a balanced debate that needs to be not only informed by current research but also by an open and honest discussion about personal use and an acknowledgemen

Large introns in relation to alternative splicing and gene evolution: a case study of Drosophila bruno-3

Background: Alternative splicing (AS) of maturing mRNA can generate structurally and functionally distinct transcripts from the same gene. Recent bioinformatic analyses of available genome databases inferred a positive correlation between intron length and AS. To study the interplay between intron length and AS empirically and in more detail, we analyzed the diversity of alternatively spliced transcripts (ASTs) in the Drosophila RNA-binding Bruno-3 (Bru-3) gene. This gene was known to encode thirteen exons separated by introns of diverse sizes, ranging from 71 to 41,973 nucleotides in D. melanogaster. Although Bru-3's structure is expected to be conducive to AS, only two ASTs of this gene were previously described. Results: Cloning of RT-PCR products of the entire ORF from four species representing three diverged Drosophila lineages provided an evolutionary perspective, high sensitivity, and long-range contiguity of splice choices currently unattainable by high-throughput methods. Consequently, we identified three new exons, a new exon fragment and thirty-three previously unknown ASTs of Bru-3. All exon-skipping events in the gene were mapped to the exons surrounded by introns of at least 800 nucleotides, whereas exons split by introns of less than 250 nucleotides were always spliced contiguously in mRNA. Cases of exon loss and creation during Bru-3 evolution in Drosophila were also localized within large introns. Notably, we identified a true de novo exon gain: exon 8 was created along the lineage of the obscura group from intronic sequence between cryptic splice sites conserved among all Drosophila species surveyed. Exon 8 was included in mature mRNA by the species representing all the major branches of the obscura group. To our knowledge, the origin of exon 8 is the first documented case of exonization of intronic sequence outside vertebrates. Conclusion: We found that large introns can promote AS via exon-skipping and exon turnover during evolution likely due to frequent errors in their removal from maturing mRNA. Large introns could be a reservoir of genetic diversity, because they have a greater number of mutable sites than short introns. Taken together, gene structure can constrain and/or promote gene evolution

The influence of a major disaster on suicide risk in the population

The authors investigated the relationship between the September 11, 2001 terrorist attacks and suicide risk in New York City from 1990 to 2006. The average monthly suicide rate over the study period was 0.56 per 100,000 people. The monthly rate after September 2001 was 0.11 per 100,000 people lower as compared to the rate in the period before. However, the rate of change in suicide was not significantly different before and after the disaster, and regression discontinuity analysis indicated no change at this date. There was no net change in the suicide rate in New York City attributable to this disaster, suggesting that factors other than exposure to traumatic events (e.g., cultural norms, availability of lethal methods) may be key drivers of suicide risk in this context.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64557/1/20473_ftp.pd

Measurement properties of asthma-specific quality-of-life measures: protocol for a systematic

Background: Asthma is a frequent chronic inflammatory disease of the airways, and the assessment of health-related quality of life (HrQoL) is important in both research and routine care. Various asthma-specific measures of HrQoL exist but there is uncertainty which measures are best suited for use in research and routine care. Therefore, the aim of the proposed research is a comprehensive systematic assessment of the measurement properties of the existing measures that were developed to measure asthma-specific quality of life. Methods/design: This study is a systematic review of the measurement properties of asthma-specific measures of health-related quality of life. PubMed and Embase will be searched using a selection of relevant search terms. Eligible studies will be primary empirical studies evaluating, describing or comparing measurement properties of asthma-specific HRQL tools. Eligibility assessment and data abstraction will be performed independently by two reviewers. Evidence tables will be generated for study characteristics, instrument characteristics, measurement properties and interpretability. The quality of the measurement properties will be assessed using predefined criteria. Methodological quality of studies will be assessed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. A best evidence synthesis will be undertaken if more than one study have investigated a particular measurement property. Discussion: The proposed systematic review will produce a comprehensive assessment of measurement properties of existing measures of asthma-specific health-related quality of life. We also aim to derive recommendations in order to help researchers and practitioners alike in the choice of instrument