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Abstract: Objective: Glycated hemoglobin (HbA1c) is a stable index of chronic glycemic status and hyperglycemia associated with progressive development of insulin resistance and frank diabetes. It is also associated with premature aging and increased mortality. To uncover novel loci for HbA1c that are associated with healthy aging, we conducted a genome-wide association study (GWAS) using non-diabetic participants in the Long Life Family Study (LLFS), a study with familial clustering of exceptional longevity in the US and Denmark. Methods: A total of 4088 non-diabetic subjects from the LLFS were used for GWAS discoveries, and a total of 8231 non-diabetic subjects from the Atherosclerosis Risk in Communities Study (ARIC, in the MAGIC Consortium) and the Health, Aging, and Body Composition Study (HABC) were used for GWAS replications. HbA1c was adjusted for age, sex, centers, 20 principal components, without and with BMI. A linear mixed effects model was used for association testing. Results: Two known loci at GCK rs730497 (or rs2908282) and HK1 rs17476364 were confirmed (p< 5e-8). Of 25 suggestive (5e-8< p <1e-5) loci, one known (G6PC2 rs560887, replication p =5e-5) and one novel (OR10R3P/SPTA1− rs12041363, replication p =1e-17) loci were replicated (p <0.0019). Similar findings resulted when HbA1c was further adjusted for BMI. Further validations are crucial for the remaining suggestive loci including the emerged variant near OR10R3P/SPTA1. Conclusions: The analysis reconfirmed two known GWAS loci (GCK, HK1) and identified 25 suggestive loci including one reconfirmed variant in G6PC2 and one replicated variant near OR10R3P/SPTA1. Future focused survey of sequence elements containing mainly functional and regulatory variants may yield additional findings. [Copyright &y& Elsevier]

A three-dimensional (3D) hydrodynamic model for the Pearl River Estuary based on Delft3D is established and calibrated to study the changes in tidal circulation and flushing in Victoria Harbour. The tidal circulation and flushing were simulated by this 3D model under the existing reclamation conditions, including Central Reclamation Phases I, II, and III (CRI, CRII, and CRIII), and Wan Chai Reclamation Phase I (WRI). The model is also applied to predict the hydrodynamic changes after the reclamation of proposed Wan Chai Development Phase II (WDII) to be constructed in 2017. Compared to the coastline in 1975 (before large-scale reclamation), the numerical results show that the following changes have taken place after the existing reclamation: (1) The peak flow at all cross sections along Victoria Harbour decreases by about 9-25%, with an average value of about 15% for the existing reclamation; (2) the peak velocity in the eastern harbour near Lei Yue Mun decreases after the existing reclamation because of the reduction of flow, but it increases in the central and western harbour due to the significant narrowing in harbour width; (3) flushing time in Victoria Harbour increases by about 25-40% in the wet season and increases by almost 15-30% in the dry season as a result of the changes of the flow discharge and tidal range. After the reclamation of WDII, the flushing rate and flow discharge in Victoria Harbour only change slightly compared with that under the existing reclamation condition. Another finding is that for the present coastline, the flushing time ranges about 1.5-2.5 days in the wet season and 5-7 days in the dry season. [ABSTRACT FROM AUTHOR]

Late-onset Alzheimer's disease (LOAD) risk is strongly influenced by genetic factors such as the presence of the apolipoprotein E ε4 allele (referred to here as APOE4), as well as non-genetic determinants including ageing. To pursue mechanisms by which these affect human brain physiology and modify LOAD risk, we initially analysed whole-transcriptome cerebral cortex gene expression data in unaffected APOE4 carriers and LOAD patients. APOE4 carrier status was associated with a consistent transcriptomic shift that broadly resembled the LOAD profile. Differential co-expression correlation network analysis of the APOE4 and LOAD transcriptomic changes identified a set of candidate core regulatory mediators. Several of these-including APBA2, FYN, RNF219 and SV2A-encode known or novel modulators of LOAD associated amyloid beta A4 precursor protein (APP) endocytosis and metabolism. Furthermore, a genetic variant within RNF219 was found to affect amyloid deposition in human brain and LOAD age-of-onset. These data implicate an APOE4 associated molecular pathway that promotes LOAD. [ABSTRACT FROM AUTHOR]

Background: VEGF is one of the key drivers of physiological or pathological angiogenesis hence several VEGF inhibitors are in different stages of clinical development. To further dissect the role of VEGF in different stages of tumor progression in lung tumors, we utilized KrasG12D-LSL GEMMs (genetically engineered mouse models). Methods: Intranasal delivery of adenoviruses expressing cre recombinase in KrasG12D-LSL mice results in the expression of mutant Kras that leads to development of tumor lesions ranging from adenomatous hyperplasia to large adenoma and adenocarcinoma over time in lung. In the current study, we treated KrasG12D-LSL mice at 14 weeks post inhalation with three different angiogenic inhibitors including axitinib and PF-00337210 both of which are selective inhibitors of VEGFR and sunitinib which targets VEGFR, C-SF1-R, PDGFR and KIT. Results: Pathology findings showed no significant difference in percentage of adenomatous hyperplastic lesions between the vehicle vs. any of the treatments suggesting that angiogenesis may not play a major role at early stages of tumorigenesis. However, each inhibitor suppressed percentage of benign adenoma lesions and almost fully inhibited growth of adenocarcinoma lesions in the recipients which was consistent with a reduction in tumor vasculature. Treatment with sunitinib which is a multi-targeted RTKI did not provide any advantage compared to selective VEGFR inhibitor further emphasizing role of VEGF in tumor angiogenesis in this model. Conclusion: Overall, our studies indicate significance of VEGF and angiogenesis in a spontaneous model of lung tumorigenesis and provide a proof of mechanism for anti-cancer activity of VEGF inhibitors in this model. [ABSTRACT FROM AUTHOR]

Partially treated wastewater discharge from marine outfall diffusers often contains inorganic and organic solids that may settle close to the source and give rise to sludge banks that affect benthic ecology. An experimental and theoretical investigation of the structure and settling mechanisms of a horizontal sediment momentum jet in stagnant ambient has been carried out. The cross-sectional particle concentration distribution of a horizontal sediment jet is measured for the first time. Bottom deposition measurements are made for a total of 41 experiments of momentum jets laden with sand particles or synthetic spherical glass particles. The sediment jet can be characterised by a sedimentation length scale defined by the jet momentum flux and particle settling velocity. The measured longitudinal sediment deposition rate can be described by a semiempirical log-normal distribution based on . In the instantaneous particle distribution, the sediment fallout is concentrated in a central region and settles in a zig-zag trajectory. The time-mean transverse particle concentration shows that the upper half of sediment jet behaves like a pure jet with concentric contours for . For , the sediment cloud starts to depart from the water jet; for , the particle cloud separates significantly from the water jet. For , the maximum particle concentration is located within the jet region and the decay of closely follows the classical jet theory. For , is significantly less than that given by the jet theory. The time-mean particle concentration distribution across the jet is horseshoe-shaped, with an open end at the bottom due to sedimentation. The concentration distribution is elongated in the vertical direction and shaped like an ellipse. A two-layer Lagrangian jet model is developed to predict the mixing of dilute horizontal sediment jets. The predictions are in excellent agreement with the layer-averaged particle concentrations and bottom deposition rate measurement. [ABSTRACT FROM AUTHOR]

Multiple buoyant jets are found in the natural and artificial environment: thermal discharges from fossil and nuclear-fueled electricity generation, domestic and industrial wastewater discharges, brine disposal from desalination plants, and various heat sources in the built environment. An overview of theoretical and experimental modeling of multiple buoyant jets over the past three decades is presented. Basic measurements of the structure of buoyant jet flows, integral jet modeling and three-dimensional numerical solutions of the Reynolds-averaged equations are reviewed. A semianalytical model is proposed to predict the dynamic interaction of multiple buoyant jets in stagnant fluid. The unknown jet trajectories are obtained from an iterative solution of an integral jet model and the irrotational external flow. Predictions are in good agreement with experiments of clustered jet groups, turbulent plume pairs, alternating diffusers, and rosette buoyant jet groups; the approach can also be extended to multiple jets in cross-flow. The mixing of a rosette buoyant jet group in a cross-flow is reviewed. The use of jet theory in solving two unconventional urban environment problems are highlighted: (1) the unraveling of the cause of the severe acute respiratory syndrome (SARS) outbreak in Hong Kong in 2003; and (2) design of a complex river junction for flood control under tight space constraints. It is suggested that experiments will remain a source of new theoretical ideas and the need for a civil engineer to solve complex problems with tractable models and analytical clarity will prevail. [ABSTRACT FROM AUTHOR]

Background: Shortening of chromosomal telomeres is a consequence of cell division and is a biological factor related to cellular aging and potentially to more rapid organismal biological aging. Objective: To determine whether shorter telomere length (TL), as measured in human blood samples, is associated with the development of Alzheimer disease and mortality. Design: We studied available stored leukocyte DNA from a community-based study of aging using realtime polymerase chain reaction analysis to determine mean TL in our modification of a method measuring the ratio of telomere sequence to single-copy gene sequence. Setting: Amultiethnic community-based study of aging and dementia. Participants: One thousand nine hundred eighty three subjects 65 years or older. Mean (SD) age at blood draw was 78.3 (6.9) years; at death, 86.0 (7.4) years. Median follow-up for mortality was 9.3 years; 190 (9.6%) developed incident dementia. Results: The TL was inversely related to age and shorter in men than women. Persons dying during follow-up had a shorter TL compared with survivors (mean [SD], 6218 [819] vs 6491 [881] base pairs [bp] [P<.001]), even after adjustment for age, sex, education, and apolipoprotein E genotype. Individuals who developed dementia had significantly shorter TL (mean [SD], 6131 [798] bp for prevalent cases and 6315 [817] bp for incident cases) compared with those remaining dementia-free (6431 [864] bp). Cox-regression analyses showed that shorter TL was a risk for earlier onset of dementia (P=.05), but stratified analyses for sex showed that this association of age at onset of dementia with shorter TL was significant in women only. Conclusion: Our findings suggest that shortened leukocyte TL is associated with risks for dementia and mortality and may therefore be a marker of biological aging. [ABSTRACT FROM AUTHOR]

Background Balanced chromosomal rearrangements occasionally have strong phenotypic effects, which may be useful in understanding pathobiology. However, conventional strategies for characterising breakpoints are laborious and inaccurate. We present here a proband with a thoracic aortic aneurysm (TAA) and a balanced translocation t(10;11) (q23.2;q24.2). Our purpose was to sequence the chromosomal breaks in this family to reveal a novel candidate gene for aneurysm. Methods and results Intracranial aneurysm (IA) and TAAs appear to run in the family in an autosomal dominant manner: After exploring the family history, we observed that the proband's two siblings both died from cerebral haemorrhage, and the proband's parent and parent's sibling died from aortic rupture. After application of a genome-wide paired-end DNA sequencing method for breakpoint mapping, we demonstrate that this translocation breaks intron 1 of a splicing isoform of Neurotrimin at 11q25 in a previously implicated candidate region for IAs and AAs (OMIM 612161). Conclusions Our results demonstrate the feasibility of genome-wide paired-end sequencing for the characterisation of balanced rearrangements and identification of candidate genes in patients with potentially disease-associated chromosome rearrangements. The family samples were gathered as a part of our recently launched National Registry of Reciprocal Balanced Translocations and Inversions in Finland (n=2575), and we believe that such a registry will be a powerful resource for the localisation of chromosomal aberrations, which can bring insight into the aetiology of related phenotypes. [ABSTRACT FROM AUTHOR]

The role of PI3K and MAPK pathways in tumor initiation and progression is well established; hence, several inhibitors of these pathways are currently in different stages of clinical trials. Recent studies identified a PI3K/mTOR (PF-04691502) and a MEK inhibitor (PD-0325901) with strong potency and efficacy in different cell lines and tumor models. PD-0325901, however, showed adverse effects when administered at or above MTD (maximum tolerated dose) in the clinic. Here, we show in preclinical models that PD-0325901 at doses well below MTD (sub-MTD 1.5 mg/kg SID) is still a potent compound as single agent or in combination with PF-04691502. We first observed that PD-0325901 at 1.5 mg/kg SID and in combination with PF-04691502 (7.5 mg/kg; SID) significantly inhibited growth of H460 (carry Kras and PIK3CA mutations) orthotopic lung tumors. Additionally, we tested efficacy of PD-0325901 in Kras(G12D-LSL) conditional GEMMs (genetically engineered mouse models) which are a valuable tool in translational research to study tumor progression. Intranasal delivery of adenoviruses expressing Cre recombinase (Adeno-Cre) resulted in expression of mutant Kras leading to development of tumor lesions in lungs including adenomatous hyperplasia, large adenoma, and adenocarcinoma. Similar to H460 tumors, PD-0325901 as single agent or in combination with PF-04691502 significantly inhibited growth of tumor lesions in lungs in Kras(G12D-LSL) mice when treatment started at adenocarcinoma stage (at 14 weeks post-Adeno-Cre inhalation). In addition, immunohistochemistry showed inhibition of pS6 (phosphorylated ribosomal S6) in the treated animals particularly in the combination group providing a proof of mechanism for tumor growth inhibition. Finally, m-CT imaging in live Kras(G12D-LSL) mice showed reduction of tumor burdens in PD-0325901-treated animals at sub-MTD dose. In conclusion, our data suggest that PD-0325901 at doses below MTD is still a potent compound capable of tumor growth inhibition where Kras and/or PI3K are drivers of tumor growth and progression. [ABSTRACT FROM AUTHOR]

Background/Aims: Genetic variants that affect estrogen activity may influence the risk of Alzheimer's disease (AD). We examined the relation of polymorphisms in the gene for the estrogen receptor-beta (ESR2) to the risk of AD in women with Down syndrome. Methods: Two hundred and forty-nine women with Down syndrome, 31-70 years of age and nondemented at baseline, were followed at 14- to 18-month intervals for 4 years. Women were genotyped for 13 single-nucleotide polymorphisms (SNPs) in the ESR2 gene, and their association with AD incidence was examined. Results: Among postmenopausal women, we found a 2-fold increase in the risk of AD for women carrying 1 or 2 copies of the minor allele at 3 SNPs in introns seven (rs17766755) and six (rs4365213 and rs12435857) and 1 SNP in intron eight (rs4986938) of ESR2. Conclusion: These findings support a role for estrogen and its major brain receptors in modulating susceptibility to AD in women. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background/Aims. Genetic variants that affect estrogen activity may influence the risk of Alzheimer's disease (AD). In women with Down syndrome, we examined the relation of polymorphisms in hydroxysteroid-17beta-dehydrogenase (HSD17B1) to age at onset and risk of AD. HSD17B1 encodes the enzyme 17β-hydroxysteroid dehydrogenase (HSD1), which catalyzes the conversion of estrone to estradiol. Methods. Two hundred and thirty-eight women with DS, nondemented at baseline, 31-78 years of age, were followed at 14-18-month intervals for 4.5 years. Women were genotyped for 5 haplotype-tagging single-nucleotide polymorphisms (SNPs) in the HSD17B1 gene region, and their association with incident AD was examined. Results. Age at onset was earlier, and risk of AD was elevated from two- to threefold among women homozygous for the minor allele at 3 SNPs in intron 4 (rs676387), exon 6 (rs605059), and exon 4 in COASY (rs598126). Carriers of the haplotype TCC, based on the risk alleles for these three SNPs, had an almost twofold increased risk of developing AD (hazard ratio = 1.8, 95% CI, 1.1-3.1). Conclusion. These findings support experimental and clinical studies of the neuroprotective role of estrogen. [ABSTRACT FROM AUTHOR]

The study aim was to estimate the genetic contribution to individual differences in different forms of memory in a large family-based group of older adults. As part of the Late Onset Alzheimer's Disease Family Study, 899 persons (277 with Alzheimer's disease, 622 unaffected) from 325 families completed a battery of memory tests from which previously established composite measures of episodic memory, semantic memory, and working memory were derived. Heritability in these measures was estimated using the maximum likelihood variance component method, controlling for age, gender, and education. In analyses of unaffected family members, the adjusted heritability estimates were 0.62 for episodic memory, 0.49 for semantic memory, and 0.72 for working memory, where a heritability estimate of 1 indicates that genetic factors explain all of the phenotypic variance and a heritability of 0 indicates that genetic factors explain none. Adjustment for APOE genotype had little effect on these estimates. When analyses included affected and unaffected family members, adjusted heritability estimates were lower (0.47 for episodic memory, 0.32 for semantic memory, 0.42 for working memory). Adjusting for APOE slightly reduced the estimate for episodic memory (0.40) but had no effect on the remaining estimates. The results indicate that memory functions are under strong genetic influence in older persons with and without AD, and are only partly attributable to APOE. This suggests that genetic analyses of memory endophenotypes may help to identify genetic variants associated with AD. [ABSTRACT FROM AUTHOR]

Objective: To reexamine the association between the neuronal sortilin-related receptor gene (SORL1) and Alzheimer disease (AD). Design: Comprehensive and unbiased meta-analysis of all published and unpublished data from case-control studies for the SORL1 single-nucleotide polymorphisms (SNPs) that had been repeatedly assessed across studies. Setting: Academic research institutions in the United States, the Netherlands, Canada, Belgium, the United Kingdom, Singapore, Japan, Sweden, Germany, France, and Italy. Participants: All published white and Asian casecontrol data sets, which included a total of 12 464 cases and 17 929 controls. Main Outcome Measures: Alzheimer disease according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) and the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (now known as the Alzheimer's Association). Results: In the white data sets, several markers were associated with AD after correction for multiple testing, including previously reported SNPs 8, 9, and 10 (P<.001). In addition, the C-G-C haplotype at SNPs 8 through 10 was associated with AD risk (P< .001). In the combined Asian data sets, SNPs 19 and 23 through 25 were associated with A Drisk (P<.001). The disease-associated alleles at SNPs 8, 9, and 10 (120 873 131-120 886 175 base pairs [bp]; C-G-C alleles), at SNP 19 (120 953 300 bp; G allele), and at SNPs 24 through 25 (120 988 611 bp; T and C alleles) were the same previously reported alleles. The SNPs 4 through 5, 8 through 10, 12, and 19 through 25 belong to distinct linkage disequilibrium blocks. The same alleles at SNPs 8 through 10 (C-G-C), 19 (G), and 24 and 25 (T and C) have also been associated with AD endophenotypes, including white matter hyperintensities and hippocampal atrophy on magnetic resonance imaging, cerebrospinal fluid measures of amyloid β-peptide 42, and full-length SORL1 expression in the human brain. Conclusion: This comprehensive meta-analysis provides confirmatory evidence that multiple SORL1 variants in distinct linkage disequilibrium blocks are associated with AD. [ABSTRACT FROM AUTHOR]

Background: Familial aggregation of dementia with Lewy bodies (DLB) remains unclear. Objectives: To determine the degree of family aggregation of DLB by comparing DLB risk between siblings of probands with clinically diagnosed DLB and siblings of probands with clinically diagnosed Alzheimer disease in a cohort of Caribbean Hispanic families and to explore the degree of aggregation of specific clinical manifestations (ie, cognitive fluctuations, visual hallucinations, and parkinsonism) in DLB. Design: Familial cohort study. Setting: Academic research. Patients: We separately compared risks of possible DLB, probable DLB, and clinical core features of DLB (cognitive fluctuations, visual hallucinations, and parkinsonism) between siblings of probands with clinically diagnosedDLB( n=344) and siblings of probands with clinically diagnosed Alzheimer disease (n=280) in 214 Caribbean Hispanic families with extended neurologic and neuropsychological assessment. Main Outcome Measures: We applied general estimating equations to adjust for clustering within families. In these models, age and proband disease status were independent variables, and disease status of siblings was the measure of disease risk and the dependent variable. Results: Compared with siblings of probands having clinically diagnosed Alzheimer disease, siblings of probands having clinically diagnosed DLB had higher risks of probable DLB (odds ratio [OR], 2.29; 95% confidence interval [CI], 1.04-5.04) and visual hallucinations (2.32; 1.16-4.64). They also had increased risks of possible DLB (OR, 1.51; 95% CI, 0.97-2.34) and cognitive fluctuations (1.55; 0.95-2.53). Conclusions: Dementia with Lewy bodies and core features of DLB aggregate in families. Compared with siblings of probands having clinically diagnosed AD, siblings of probands having clinically diagnosed DLB are at increased risks of DLBand visual hallucinations. These findings are an important step in elucidating the genetic risk factors underlying DLB and in delineating DLB from other neurodegenerative diseases, such as Alzheimer disease. [ABSTRACT FROM AUTHOR]

The East River (Dong Jiang), a major tributary of the Pearl River (Zhu Jiang, the second largest river in China by discharge), is situated in southern China, which has the highest rates of urbanization and development on Earth. The East River also provides 80% of Hong Kong’s water supply. However, there have been no ecological studies to examine the combined impacts of changes in land use and water quality degradation on this river ecosystem. We tested the hypothesis that land-use disturbance and water quality degradation would significantly reduce benthic biodiversity in the East River by investigating macroinvertebrate community composition and relating it to data on water quality and catchment condition. The percentage of total impervious area within each catchment (%TIA—an indicator of land-use disturbance) was negatively related to a composite water quality index—the ERWQI—we developed for the East River. Modeling by partial least squares projection to latent structures (PLS) showed that family richness and relative abundance index (RAI) of macroinvertebrates were strongly influenced by both %TIA and ERWQI. Multi-response permutation procedure (MRPP) tests showed highly significant differences in family richness composition and RAI of macroinvertebrates among sites in the upper, middle, and lower course of the East River. MRPP also revealed differences in the family richness composition of nighttime drift samples between upper and middle site groups. Abundance (individuals m−3) and total family richness of drifting macroinvertebrates at each site were positively related to %TIA (range: 1.0–8.5%), while drift biomass was negatively related to dissolved oxygen and positively related to total suspended solids. Thus, human disturbances associated with land-use changes (increasing %TIA) and nutrient inputs severely degraded ecosystem integrity and the water quality of the East River and thereby reduced aquatic biodiversity. [ABSTRACT FROM AUTHOR]

Deep Bay is a semienclosed bay that receives sewage from Shenzhen, a fast-growing city in China. NH4 is the main N component of the sewage (>50% of total N) in the inner bay, and a twofold increase in NH4 and PO4 concentrations is attributed to increased sewage loading over the 21-year period (1986-2006). During this time series, the maximum annual average NH4 and PO4 concentrations exceeded 500 and 39 μM, respectively. The inner bay (Stns DM1 and DM2) has a long residence time and very high nutrient loads and yet much lower phytoplankton biomass (chlorophyll (Chl) <10 μg L-1 except for Jan, July, and Aug) and few severe long-term hypoxic events (dissolved oxygen (DO) generally >2 mg L-1) than expected. Because it is shallow (~2 m), phytoplankton growth is likely limited by light due to mixing and suspended sediments, as well as by ammonium toxicity, and biomass accumulation is reduced by grazing, which may reduce the occurrence of hypoxia. Since nutrients were not limiting in the inner bay, the significant long-term increase in Chl a (0.52-0.57 μg L-1 year-1) was attributed to climatic effects in which the significant increase in rainfall (11 mm year-1) decreased salinity, increased stratification, and improved water stability. The outer bay (DM3 to DM5) has a high flushing rate (0.2 day-1), is deeper (3 to 5 m), and has summer stratification, yet there are few large algal blooms and hypoxic events since dilution by the Pearl River discharge in summer, and the invasion of coastal water in winter is likely greater than the phytoplankton growth rate. A significant long-term increase in NO3 (0.45-0.94 μM year-1) occurred in the outer bay, but no increasing trend was observed for SiO4 or PO4, and these long-term trends in NO3, PO4, and SiO4 in the outer bay agreed with those long-term trends in the Pearl River discharge. Dissolved inorganic nitrogen (DIN) has approximately doubled from 35-62 to 68- 107 μM in the outer bay during the last two decades, and consequently DIN to PO4 molar ratios have also increased over twofold since there was no change in PO4. The rapid increase in salinity and DO and the decrease in nutrients and suspended solids from the inner to the outer bay suggest that the sewage effluent from the inner bay is rapidly diluted and appears to have a limited effect on the phytoplankton of the adjacent waters beyond Deep Bay. Therefore, physical processes play a key role in reducing the risk of algal blooms and hypoxic events in Deep Bay. [ABSTRACT FROM AUTHOR]

The size-fractionated phytoplankton biomass and primary production were investigated in four contrasting areas of Hong Kong waters in 2006. Phytoplankton biomass and production varied seasonally in response to the influence of the Pearl River discharge. In the dry season, the phytoplankton biomass and production were low (<42 mg chl m-2 and <1.8 g C m-2day-1) in all four areas, due to low temperatures and dilution and reduced light availability due to strong vertical mixing. In contrast, in the wet season, in the river-impacted western areas, the phytoplankton biomass and production increased greater than five-fold compared to the dry season, especially in summer. In summer, algal biomass was 15-fold higher than in winter, and the mean integrated primary productivity (IPP) was 9 g C m-2day-1 in southern waters due to strong stratification, high temperatures, light availability, and nutrient input from the Pearl River estuary. However, in the highly flushed western waters, chl a and IPP were lower (<30 mg m-2 and 4 g C m-2day-1, respectively) due to dilution. The maximal algal biomass and primary production occurred in southern waters with strong stratification and less flushing. Spring blooms (>10 μg chlaL-1) rarely occurred despite the high chl-specific photosynthetic rate (mostly >10 μg C μg chla-1day-1) as the accumulation of algal biomass was restricted by active physical processes (e.g., strong vertical mixing and freshwater dilution). Phytoplankton biomass and production were mostly dominated by the >5-μm size fraction all year except in eastern waters during spring and mostly composed of fast-growing chain-forming diatoms. In the stratified southern waters in summer, the largest algal blooms occurred in part due to high nutrient inputs from the Pearl River estuary. [ABSTRACT FROM AUTHOR]

The article discusses a study which compares the methods, nutrient enrichment bioassays, ambient nutrient ratios and turnover times of phosphorus that are applied to evaluate which nutrient most limits phytoplankton growth in Hong Kong, China. Researchers believe that knowing which nutrient is limiting the growth of phytoplankton is important in order to alleviate hypoxia. They conclude that the comparison of bioassays and nutrient ratios indicates that nutrient ratios are an effective method to predict limiting nutrient.

Analysis of multiple traits can provide additional information beyond analysis of a single trait, allowing better understanding of the underlying genetic mechanism of a common disease. To accommodate multiple traits in familial correlation analysis adjusting for confounders, we develop a regression model for canonical correlation parameters and propose joint modeling along with mean and scale parameters. The proposed method is more powerful than the regression method modeling pairwise correlations because it captures familial aggregation manifested in multiple traits through maximum canonical correlation. [ABSTRACT FROM AUTHOR]

Submarine ocean outfalls are commonly used for the disposal of partially treated effluents in coastal cities. Typically, the greatest environmental risk caused by toxic substances occurs in the near field of the outfall discharge. The ecological impact of the effluent varies greatly under different discharge and environmental conditions that are characterized by both regular and stochastic variations. For a comprehensive environmental risk assessment of a coastal discharge, it is necessary to determine both the likelihood and severity of the adverse effects on the biological community. We present the first integrated stochastic (Monte Carlo) environmental risk assessment of a major coastal sewage outfall discharge - the Stonecutters Island outfall of the Harbour Area Treatment Scheme (HATS) in Hong Kong. Unionized ammonia (NH3) is used as the target pollutant. To accurately envisage the ambient concentrations of NH3, a Lagrangian jet model (JETLAG/VISJET) is used to analyze pollutant concentrations in the nearfield of the outfall. The environmental conditions are simulated from 3D hydrodynamic model simulations over a 4 month period fortypical wet and dry seasons. Statistical characteristics of the effluent discharge and receiving water temperature are derived from field data. The probability distribution of predicted exposure concentrations (EC) is generated from this integrated simulation. A species sensitivity distribution, which represents a statistical distribution of threshold sublethal effects levels or benchmark concentrations (BC) for various marine organisms is constructed using available chronic toxicity data. The environmental risk of NH3 on the marine community is characterized by computing statistical distributions of Hazard Quotient (HA = EC/BC) using Monte Carlo simulation. It is found that the probability of HQ > 1 for HATS Stage 1(1.6 million m³/day sewage treated with chemically enhanced primary treatment) is around 0.11 for wet season but just about 0.06 for the dry season. The risk increases by about 10% to 0.08-0.13 with additional sewage loads of 0.8 million m³/day at the same level of treatment (HATS Stage 2A). With an upgrade to secondary treatment (HATS Stage 2B), the probability will be reduced to 0.03-0.05. Compared to the use of "worst case" scenarios or point pollution threshold estimates, the present method offers a more holistic ecological assessment, and is much less sensitive to arbitrary choice of model parameters. The present risk assessment approach can be readily extended to the accurate determination of mixing zones based on statistical evaluation of ecological risks. [ABSTRACT FROM AUTHOR]

A tangential vortex intake is a compact structure that can convey storm water efficiently as a swirling flow down a vortex dropshaft. It has been studied in physical models and successfully employed in urban drainage and hydroelectric plant applications, but a comprehensive account of the key flow characteristics has not been reported and a theoretical design guideline of a tangential intake is not available. In this study the hydraulics of tangential slot vortex intakes is investigated via extensive experiments. It is found that the flow in the tapering and downward sloping vortex inlet channel is strongly dependent on the geometry of the inlet and dropshaft. Under some conditions, hydraulic instability and overflow can occur, rendering the design ineffective. It is shown that the hydraulic stability depends on the discharge at which flow control shifts from upstream to downstream (Qc), as well as the free drainage discharge (Qf). A theoretical design criterion for stable flow is developed in terms of Qf and Qc as a function of the vortex inlet geometry. For a “stable” design, the flow in the tapering inlet evolves from supercritical flow to subcritical flow smoothly as the discharge increases. Fifteen different tangential vortex intake models are tested. The experimental observations are in excellent agreement with the theoretical prediction. The present study provides a general guideline for designing a tangential vortex intake that can convey the flow smoothly without unstable fluctuating flow associated with a hydraulic jump. [ABSTRACT FROM AUTHOR]