Physical and biological consequences of a climate event in the central North Pacific

Climatic changes over the North Pacific which began in the mid 1970s, peaked in the early 1980s, and ended by the late 1980s, appear to have altered productivity at various trophic levels in the marine ecosystem in the central North Pacific. The climatic change resulted in increased mixed layer depth and the frequency of deep mixing events, particularly during January-March. A number of biological time series for species ranging from primary to apex levels in the North-western Hawaiian Islands, show corresponding declines in productivity of 30–50% from the early 1980s to the present. We hypothesize that during the early 1980s, increased mixing due to the climate event resulted in greater nutrient input into the euphotic zone and ultimately increased ecosystem productivity. Productivity over a range of trophic levels declined when the climate event ended.     

Impact of the Leeuwin Current on the spatial distribution of the puerulus settlement of the western rock lobster (Panulirus cygnus) and implications for the fishery of Western Australia

Previous studies have shown that the strength of the Leeuwin Current is correlated with the level of the puerulus (post-larval stage) settlement in the western rock lobster ( Panulirus cygnus ). The level of puerulus settlement has also been shown to be a reliable predictor of catch in the rock lobster fishery in Western Australia, 3 and 4 yr later. This study examines the impact of the south-flowing Leeuwin Current on the spatial distribution of the puerulus settlement along the coast based on information from 10 settlement sites. In years of strong Leeuwin Current, the location of the peak settlement occurs further south by up to 2° latitude compared with years of weak Leeuwin Current. The key months of Leeuwin Current strength that affect the abundance of the puerulus settlement are generally February to April, during the early larval stages. However, the months that affect the spatial distribution are from June onwards, which is closer to the period of puerulus settlement that starts in about August each year. The mean latitude of puerulus settlement shows a very good relationship with Leeuwin Current strength in June to December ( r  = 0.86, P  < 0.001). The variation in spatial distribution in puerulus settlement can be used to predict the spatial distribution of fishing effort and catch, 3 and 4 yr later ( r  = 0.78 and 0.84, respectively, P  < 0.001).     

Network Structure,Knowledge Governance,and Firm Performance: Evidence from Innovation Networks and SMEs in the UK

It is increasingly understood that learning and thus innovation often occurs via highly interactive, iterative, network‐based processes. Simultaneously, economic development policy is increasingly focused on small and medium‐sized enterprises (SMEs) as a means of generating growth, creating a clear research issue in terms of the roles and interactions of government policy, universities, and other sources of knowledge, SMEs, and the creation and dissemination of innovation. This paper analyses the contribution of a range of actors in an SME innovation creation and dissemination framework, reviewing the role of various institutions therein, exploring the contribution of cross‐locality networks, and identifying the mechanisms required to operationalise such a framework. Bivariate and multivariate (regression) techniques are employed to investigate both innovation and growth outcomes in relation to these structures; data are derived from the survey responses of over 450 SMEs in the UK. Results are complex and dependent upon the nature of institutions involved, the type of knowledge sought, and the spatial level of the linkages in place but overall highlight the value of cross‐locality networks, network governance structures, and certain spillover effects from universities. In general, we find less support for the factors predicting SME growth outcomes than is the case for innovation. Finally, we outline an agenda for further research in the area.     

Interactions between climate and population density in the episodic recruitment of bocaccio,Sebastes paucispinis,a Pacific rockfish

Climate strongly influences the population dynamics of many species, but intrinsic and extrinsic factors such as density‐dependence and anthropogenic impacts can confound the effects of climate. Further, the temporal scale of climate response is determined by the unique characteristics of a species’ life history, and determining the most appropriate climate indicator at the proper scale is a challenge faced by population ecologists. We focused on how climate influences juvenile survival of bocaccio (Sebastes paucispinis), a threatened Pacific rockfish, because its abundance has declined >90% in the last 25 years, ostensibly as the result of overfishing. Bocaccio recruitment is episodic, with strong recruitment events apparently related to climate conditions. We developed a sequence of models that related log of juvenile survival to the predictor variables population density and climate, as measured by the Northern Oscillation Index. A model that contained only population density as a predictor variable explained only 1.4% of the variance, while a model that included only climate indices explained 52%. Including density additively with climate did not improve model fit. However, a model that included an interaction between density and climate explained more than 68% of the variance. In addition, models that represented climate as monthly indices fit the juvenile survival data much better than those that averaged climate over 2‐ or 3‐month periods. Our results suggest that climate affects bocaccio recruitment as a series of pulses corresponding to particular life‐history events, with population density mediating the magnitude of the climate effect during the settlement stage.     

Role of phenotypic plasticity in morphological differentiation between watersnake populations

An individual's morphology is shaped by the environmental pressures it experiences, and the resulting morphological response is the culmination of both genetic factors and environmental (non‐genetic) conditions experienced early in its life (i.e. phenotypic plasticity). The role that phenotypic plasticity plays in shaping phenotypes is important, but evidence for its influence is often mixed. We exposed female neonate diamond‐backed watersnakes (Nerodia rhombifer) from populations experiencing different prey‐size regimes to different feeding treatments to test the influence of phenotypic plasticity in shaping trophic morphology. We found that snakes in a large‐prey treatment from a population frequently encountering large prey exhibited a higher growth rate in body size than individuals in a small‐prey treatment from the same population. This pattern was not observed in snakes from a population that regularly encounters small prey. We also found that regardless of treatment, snakes from the small‐prey population were smaller at birth than snakes from the large‐prey population and remained so throughout the study. These results suggest that the ability to plastically respond to environmental pressures may be population‐specific. These results also indicate a genetic predisposition towards larger body sizes in a population where large prey items are more common.     

RADIOGRAPHY AND COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF NONNEOPLASTIC EQUINE MANDIBULAR DISEASE

We compared the information gained from computed tomography (CT) vs. radiography in horses with nonneoplastic disease of the mandible. We hypothesized that CT would provide additional diagnostic information. Medical records, radiographs, and CT images of horses with nonneoplastic mandibular disease evaluated between 1994 and 2008 were reviewed. Nineteen horses were identified; 11 had a tooth root abscess and related disease, four had a fracture of the teeth and/or mandible, and four had a nonneoplastic mass. Both CT images and radiographs allowed identification of diseased teeth that appeared clinically normal otherwise. CT allowed identification of teeth that were clinically affected but appeared normal radiographically. Parameters such as tooth pulp involvement, lamina dura destruction, presence of bone fragments, lingual and buccal mandibular bone periosteal reaction, and cortical bone destruction were more conspicuous with CT. Performing radiography and CT in horses with nonneoplastic mandibular disease provides a more complete evaluation than either technique alone. CT contributes additional information that could otherwise be overlooked with radiographs alone in horses with a mandibular fracture. CT provides ancillary information to radiographs in horses with dental infection or a nonneoplastic mass of the mandible.     

The fine-scale mapping of grassland protein densities

A simple and accurate remote sensing technique for the fine-scale mapping of grassland protein densities was developed during a study of sward quality and antelope dispersion in Kenya, East Africa. Using measures of spectral reflectance and a vehicular navigation system, estimates of protein densities were recorded at rates exceeding 1000 samples per hour. Nitrogen analyses confirmed that reflectance measures were accurate predictors of protein density for a variety of grass swards but not for two species of sedge. Because the regression coefficients linking reflectance to protein density differed significantly between sward types, good estimates using this method will require a separate calibration for each type of grassland. By monitoring and correcting for variations in ambient light levels, the method can be used under a wide range of lighting conditions and for long periods. This facilitates sampling sufficiently systematically and intensively that contour plots of protein density can be constructed and then correlated with distributions of underlying abiotic factors, foraging activity of sympatric herbivores, or prior maps to characterize successional and historical change.     

USE OF CONTRAST-ENHANCED COMPUTED TOMOGRAPHY TO ASSESS ANGIOGENESIS IN DEEP DIGITAL FLEXOR TENDONOPATHY IN A HORSE

We compared contrast-enhanced computed tomography (CT) and high field magnetic resonance (MR) imaging in a horse with deep digital flexor tendonopathy. Lesions in the distal extremity were documented grossly and histopathologically. In contrast-enhanced CT, the deep digital flexor tendon lesions were markedly contrast enhancing with evidence of angiogenesis in the core and dorsal border lesions. The lesion morphology was clearly delineated on MR imaging, but without contrast media angiogenesis cannot be identified. Gross examination, histopathologic examination, and CD31 immunohistochemistry confirmed the tendonopathy and an increased presence of small blood vessels. In this horse, deep digital flexor tendon lesions appeared similarly on contrast-enhanced CT and MR imaging. Contrast-enhanced CT may be an alternative to MR imaging for assessing tendon and ligament injury in the digit of the horse.