Adaptation and application of multivariate AMBI (M-AMBI) in US coastal waters.

The multivariate AMBI (M-AMBI) is an extension of the AZTI Marine Biotic Index (AMBI) that has been used extensively in Europe, but not in the United States. In a previous study, we adapted AMBI for use in US coastal waters (US AMBI), but saw biases in salinity and score distribution when compared to locally calibrated indices. In this study we modified M-AMBI for US waters and compared its performance to that of US AMBI. Index performance was evaluated in three ways: 1) concordance with local indices presently being used as management tools in three geographic regions of US coastal waters, 2) classification accuracy for sites defined a priori as good or bad and 3) insensitivity to natural environmental gradients. US M-AMBI was highly correlated with all three local indices and removed the compression in response seen in moderately disturbed sites with US AMBI. US M-AMBI and US AMBI did a similar job correctly classifying sites as good or bad in local validation datasets (83 to 100% accuracy vs. 84 to 95%, respectively). US M-AMBI also removed the salinity bias of US AMBI so that lower salinity sites were not more likely to be incorrectly classified as impaired. The US M-AMBI appears to be an acceptable index for comparing condition across broad-scales such as estuarine and coastal waters surveyed by the US EPA's National Coastal Condition Assessment, and may be applicable to areas of the US coast that do not have a locally derived benthic index.

Comparing volunteer and professionally collected monitoring data from the rocky subtidal reefs of Southern California, USA.

Volunteer-based citizen monitoring has increasingly become part of the natural resources monitoring framework, but it is often unclear whether the data quality from these programs is sufficient for integration with traditional efforts conducted by professional scientists. At present, the biological and physical characteristics of California's rocky reef kelp forests are concurrently monitored by two such groups, using similar methodologies--underwater visual census (UVC) of fish, benthic invertebrates, and reef habitat, though the volunteer group limits their sampling to transects close to the reef surface and they use a more constrained list of species for enumeration and measurement. Here, we compared the data collected from 13 reefs that were sampled by both programs in 2008. These groups described relatively similar fish communities, total fish abundance and abundance of the dominant fish species but there were some differences in the measured size distributions of the dominant fish species. Descriptions of the benthic invertebrate community were also similar, though there were some differences in relative abundance that may have resulted from the less detailed subsampling protocols used by the volunteers. The biggest difference was in characterization of the physical habitat of the reefs, which appeared to result from selection bias of transect path by the volunteer program towards more complex structured sections of a reef. Changes to address these differences are relatively simple to implement and if so, offer the promise of better integration of the trained volunteer monitoring with that of professional monitoring groups.

Benthic habitat condition of the continental shelf surrounding oil and gas platforms in the Santa Barbara Channel, Southern California.

The continental shelf of southern California is an important location for the extraction of petroleum and natural gas. Many platforms in the region have been operating for more than four decades and are being targeted for decommissioning. Information on the condition of surrounding habitats to the platforms will be important for regulators. The condition of sediments near (250 m-2 km) four active oil/gas platforms was evaluated with measures of macrobenthic infauna, toxicity, and chemical composition using standardized assessment indices and compared to that of equivalent locations across the region without platforms. Assessment scores indicated that the sediments surrounding the oil platforms were in a relatively good state, with reference-condition infauna, minimal levels of chemical exposure, and five instances (25% of samples) of low-level toxicity. Samples from around the oil platforms were in overall similar condition to the region, with slightly better condition infauna, nearly identical chemistry, and slightly worse toxicity.

Selecting Comparator Sites for Ecological Causal Assessment Based on Expected Biological Similarity.

Sites in poor ecological condition often require causal assessment to determine appropriate follow-up actions. Site-specific causal assessments can be time consuming. To streamline the process, we describe a quantitative method that expedites a key component of causal assessment: identifying a group of ecologically similar (comparator) sites that are used to compare and contrast biological condition and stressor exposure at the site of interest. A good set of comparator sites should: 1. Be capable of supporting similar biota to the impaired site in the absence of disturbance; 2. Comprise a gradient of biotic condition; and 3. Contain enough sites to assess variability. We used expected biological similarity to select good sets of comparator sites from a large pool of potential sites. Expected biological similarity was measured as Bray-Curtis dissimilarity values (BC) calculated from the expected benthic macroinvertebrate taxa lists produced by a predictive biotic index of stream health. Sets of comparator sites were created for 15 demonstration sites across Southern California in poor condition. We examined the stressor and biological data collected at the 15 sites and their comparators to assess the likelihood that four example stressors - total nitrogen, ammonia, specific conductivity, and bifenthrin - contribute to the poor biotic conditions that were observed. We were able to select more than 100 comparator sites for all but 1 of the 15 demonstration sites at a BC <0.1. These sets of comparator sites were then used to evaluate the four example stressors using two commonly used causal assessment types of evidence. Elevated conductivity was the most frequently supported likely cause among the demonstration sites, though total nitrogen and bifenthrin were also indicated at some sites. Though our specific approach was tailored for application in California's stream bioassessment framework, the concepts could be adapted for any bioassessment program with a large amount of sample data and an associated predictive index of biotic condition. Furthermore, this approach lays the groundwork for developing a novel approach to causal assessment that begins with a rapid, screening-level evaluation of stressors common in a region using these data-rich groups of comparator sites, which then informs follow-up management actions.

Non-Mechanical Large-Bowel Obstruction.

Four cases of non-mechanical large-bowel obstruction are presented and the significant clinical features considered. The importance of barium-enema examination in doubtful cases is emphasized, and the places of conservative and operative treatment in this condition are defined.

The Management of Closed Liver Trauma Treated by Hemihepatectomy.

A case of closed liver trauma treated by hemihepatectomy is described, and the management of the metabolic derangements following this operation are discussed.

Non-functioning Palliative Gastro-enterostomy.

The cases of three patients are reported in whom palliative gastro-enterostomy failed to provide adequate drainage, although no mechanical obstruction was found on reoperation. It appeared that local propulsive failure was responsible. Details of a technique to reduce stasis at the anastomotic site are suggested, and the use of sympathetic blocking drugs is proposed in the treatment of the established case.

Anastomotic Ulceration.

Seventy-eight operations on 68 patients with suspected anastomotic ulceration have been analysed. The incidence, investigation, diagnosis and management of this condition are discussed. SUMMARY: Seventy-eight operations on 68 patients with anastomotic ulceration have been assessed. Only 50% of these patients had a completely satisfactory result. Problems of investigations and diagnosis are discussed. It is suggested that better results can be obtained by a careful selection of patients for operation, and choice of the appropriate operation following full investigation.

The Surgical Treatment of Pyloric Obstruction due to Peptic Ulceration.

The results of surgery in 232 cases of peptic ulcer complicated by pyloric obstruction have been reviewed and the results of different operative procedures compared. SUMMARY: In this series vagotomy and drainage gave much better results in the presence of pyloric obstruction than in the treatment of peptic ulcer in general, whereas the results of Pólya gastrectomy appear marginally worse. It appears that the risk of stomal ulceration is the major difference, as the stomal ulcer rate for vagotomy and drainage in the presence of pyloric obstruction was 2% as compared with 8% in the total series. Conversely, the incidence of stomal ulcer following gastrectomy appears to be slightly increased. These findings suggest that vagotomy with drainage is the treatment of choice in pyloric obstruction.

The Results of Surgical Treatment for Peptic Ulceration, 1960 - 1964.

The results of 530 consecutive operations for peptic ulceration have been assessed and classified as satisfactory or unsatisfactory. The disabilities which determined the result have been analysed, and their incidences after gastrectomy and after vagotomy and drainage compared.