Modelling Braided River Morphodynamics Using a Particle Travel Length Framework

Numerical models that predict channel evolution are an essential tool for investigating processes that occur over timescales which render field observation intractable. The current generation of morphodynamic models, however, either oversimplify the relevant physical processes or, in the case of more physically complete codes based on computational fluid dynamics (CFD), have computational overheads that severely restrict the space–time scope of their application. Here we present a new, open-source, hybrid approach that seeks to reconcile these modelling philosophies. This framework combines steady-state, two-dimensional CFD hydraulics with a rule-based sediment transport algorithm to predict particle mobility and transport paths which are used to route sediment and evolve the bed topography. Data from two contrasting natural braided rivers (Rees, New Zealand, and Feshie, United Kingdom) were used for model verification, incorporating reach-scale quantitative morphological change budgets and volumetric assessment of different braiding mechanisms. The model was able to simulate 8 of the 10 empirically observed braiding mechanisms from the parameterized bed erosion, sediment transport, and deposition. Representation of bank erosion and bar edge trimming necessitated the inclusion of a lateral channel migration algorithm. Comparisons between simulations based on steady effective discharge versus event hydrographs discretized into a series of model runs were found to only marginally increase the predicted volumetric change, with greater deposition offsetting erosion. A decadal-scale simulation indicates that accurate prediction of event-scale scour depth and subsequent deposition present a methodological challenge because the predicted pattern of deposition may never “catch up” to erosion if a simple path-length distribution is employed, thus resulting in channel over-scouring. It may thus be necessary to augment path-length distributions to preferentially deposit material in certain geomorphic units. We anticipate that the model presented here will be used as a modular framework to explore the effect of different process representations, and as a learning tool designed to reveal the relative importance of geomorphic transport processes in rivers at multiple timescales

Long-Term Monitoring Of A High-Latitude Coral Reef System Off Southeast Florida, Usa: A Partnership Between Academia And Resource Management

Significant coral reef community development exists along the eastern shelf of the United States from the Dry Tortugas through the Florida Keys (Monroe County) and Southeast (SE) Florida (Miami-Dade, Broward, Palm Beach, and Martin Counties). State and county resource managers have partnered with academia to monitor the health of the SE Florida reef system. Since 2000, more than 20 sites have been monitored annually offshore Broward County. Quantitative data includes stony coral species cover, colony size, density, and condition (bleaching, disease, etc.) and gorgonian and sponge density. The SE Florida Coral Reef Evaluation and Monitoring Project (SECREMP) was established in 2003 as an expansion of the Florida Keys Coral Reef Evaluation and Monitoring Project (CREMP). Thirteen SECREMP sites are monitored annually across the 4 SE Florida counties. The stony coral, gorgonian, sponge, and other functional group cover data collected within the SECREMP sites and the Keys CREMP sites provides status and trend information for the entire Florida reef tract. The SE Florida reef system typically has 2-4% stony coral cover with more than 30 stony coral species and a diverse assemblage of octocoral, sponges, and fishes. Since their inception, monitoring efforts have shown relatively stable levels in stony coral cover and density. However, there have been many impacts to the SE Florida ecosystem resulting from its proximity to the highly developed and urbanized SE Florida coast. These reefs are influenced by many factors including commercial and recreational fishing and diving, major shipping ports, sewer outfalls, ship groundings, and coastal construction activities. SE Florida’s coral reef ecosystems generate $1.1 billion in annual income and support 36,000 jobs in the region. The uniqueness and value of these resources to the community demands sustained cooperative monitoring efforts and increased investigations into limiting environmental/ecological processes

Closing a Sediment Budget for a Reconfigured Reach of the Provo River, Utah

We quantified all components of a fluvial sediment budget for a discrete flood on an aggrading gravel bed river. Bed load transport rates were measured at the upstream and downstream ends of a 4 km study area on the Provo River, Utah, during a dam-controlled flood. We also collected high-resolution measurements of channel topography before and after the controlled flood for the entire reach. Topographic uncertainty in the digital elevation models (DEM) was characterized using a spatially variable approach. The net sediment flux provided unambiguous indication of storage. Sediment input to the reach (319 m3) exceeded output (32 m3), producing a net accumulation of approximately 290 m3. The difference between the scour and fill was also positive (470 m3), but uncertainty in the topographic differencing was larger than the observed net storage. Thus, the budget would have been indeterminate if based on morphologic data alone. Although topographic differencing was not sufficiently accurate to indicate net storage, it was able to demonstrate that internal erosion was a larger sediment source than the net sediment flux. The magnitude of total erosion (1454 m3) and deposition (1926 m3) was considerably larger than net change in storage, showing that internal sources and sinks were the dominant driver of channel change. The findings provide guidance for the development of sediment budgets in settings in which one must choose between a morphological approach and the direct measurement of sediment flux

Modelling Eurasian Beaver Foraging Habitat and Dam Suitability, for Predicting the Location and Number of Dams Throughout Catchments in Great Britain

Eurasian beaver (Castor fiber) populations are expanding across Europe. Depending on location, beaver dams bring multiple benefits and/or require management. Using nationally available data, we developed: a Beaver Forage Index (BFI), identifying beaver foraging habitat, and a Beaver Dam Capacity (BDC) model, classifying suitability of river reaches for dam construction, to estimate location and number of dams at catchment scales. Models were executed across three catchments, in Great Britain (GB), containing beaver. An area of 6747 km2 was analysed for BFI and 16,739 km of stream for BDC. Field surveys identified 258 km of channel containing beaver activity and 89 dams, providing data to test predictions. Models were evaluated using a categorical binomial Bayesian framework to calculate probability of foraging and dam construction. BFI and BDC models successfully categorised the use of reaches for foraging and damming, with higher scoring reaches being preferred. Highest scoring categories were ca. 31 and 79 times more likely to be used than the lowest for foraging and damming respectively. Zero-inflated negative binomial regression showed that modelled dam capacity was significantly related (p = 0.01) to observed damming and was used to predict numbers of dams that may occur. Estimated densities of dams, averaged across each catchment, ranged from 0.4 to 1.6 dams/km, though local densities may be up to 30 dams/km. These models provide fundamental information describing the distribution of beaver foraging habitat, where dams may be constructed and how many may occur. This supports the development of policy and management concerning the reintroduction and recolonisation of beaver

North Carolina macular dystrophy (MCDR1) caused by a novel tandem duplication of the PRDM13 gene

PURPOSE: To identify the underlying cause of disease in a large family with North Carolina macular dystrophy (NCMD). METHODS: A large four-generation family (RFS355) with an autosomal dominant form of NCMD was ascertained. Family members underwent comprehensive visual function evaluations. Blood or saliva from six affected family members and three unaffected spouses was collected and DNA tested for linkage to the MCDR1 locus on chromosome 6q12. Three affected family members and two unaffected spouses underwent whole exome sequencing (WES) and subsequently, custom capture of the linkage region followed by next-generation sequencing (NGS). Standard PCR and dideoxy sequencing were used to further characterize the mutation. RESULTS: Of the 12 eyes examined in six affected individuals, all but two had Gass grade 3 macular degeneration features. Large central excavation of the retinal and choroid layers, referred to as a macular caldera, was seen in an age-independent manner in the grade 3 eyes. The calderas are unique to affected individuals with MCDR1. Genome-wide linkage mapping and haplotype analysis of markers from the chromosome 6q region were consistent with linkage to the MCDR1 locus. Whole exome sequencing and custom-capture NGS failed to reveal any rare coding variants segregating with the phenotype. Analysis of the custom-capture NGS sequencing data for copy number variants uncovered a tandem duplication of approximately 60 kb on chromosome 6q. This region contains two genes, CCNC and PRDM13. The duplication creates a partial copy of CCNC and a complete copy of PRDM13. The duplication was found in all affected members of the family and is not present in any unaffected members. The duplication was not seen in 200 ethnically matched normal chromosomes. CONCLUSIONS: The cause of disease in the original family with MCDR1 and several others has been recently reported to be dysregulation of the PRDM13 gene, caused by either single base substitutions in a DNase 1 hypersensitive site upstream of the CCNC and PRDM13 genes or a tandem duplication of the PRDM13 gene. The duplication found in the RFS355 family is distinct from the previously reported duplication and provides additional support that dysregulation of PRDM13, not CCNC, is the cause of NCMD mapped to the MCDR1 locus

Primary recovery factor as a function of production rate: implications for conventional reservoirs with different drive mechanisms

This study evaluates the dependency of production rate on the recovery of hydrocarbon from conventional reservoirs using MBAL simulator. The results indicated that the recoveries are sensitive to the production rate in almost all hydrocarbon reservoirs. It was also found that the recovery of volumetric gas drive reservoirs is not impacted by the production rate. In fact, any increase in the production rate improves gas recovery in weak and strong water drive reservoirs. Moreover, increasing the production rate in oil reservoirs decreases the recovery with a significant effect observed in the weak water drive reservoirs. The results of this study demonstrate the need for implementing an effective reservoir management in order to obtain a maximum recovery

Testosterone treatment is not associated with increased risk of adverse cardiovascular events: results from the Registry of Hypogonadism in Men (RHYME).

SummaryAims The aim of this study was to assess cardiovascular (CV) safety of testosterone replacement therapy (TRT) in a large, diverse cohort of European men with hypogonadism (HG). Methods The Registry of Hypogonadism in Men (RHYME) was designed as a multi-national, longitudinal disease registry of men diagnosed with hypogonadism (HG) at 25 clinical sites in six European countries. Data collection included a complete medical history, physical examination, blood sampling and patient questionnaires at multiple study visits over 2–3 years. Independent adjudication was performed on all mortalities and CV outcomes. Results Of 999 patients enrolled with clinically diagnosed HG, 750 (75%) initiated some form of TRT. Registry participants, including both treated and untreated patients, contributed 23 900 person-months (99.6% of the targeted) follow-up time. A total of 55 reported CV events occurred in 41 patients. Overall, five patients died of CV-related causes (3 on TRT, 2 untreated) and none of the deaths were adjudicated as treatment-related. The overall CV incidence rate was 1522 per 100 000 person-years. CV event rates for men receiving TRT were not statistically different from untreated men (P=.70). Regardless of treatment assignment, CV event rates were higher in older men and in those with increased CV risk factors or a prior history of CV events. Conclusions Age and prior CV history, not TRT use, were predictors of new-onset CV events in this multi-national, prospective hypogonadism registry