Petrarch's Principle: how protected human-made reefs can help the reconstruction of fisheries and marine ecosystems

Petrarch's Principle, named here, is to know things unseen, yet to ignore things seen. We apply the principle to the debate over the appropriate role and utility of human-made reefs (HMRs) in fishery and ecosystem management by reviewing four linked issues that were discussed at the recent 7th International Conference on Artificial Reefs and Related Aquatic Habitats. First, deploying protected HMRs can help to mitigate the depletion of fishery stocks through overharvest and habitat degradation. Secondly, to achieve this objective effectively, it is essential that HMRs are protected as no-take areas, and that, thirdly, HMRs are large, well-planned, evaluated and monitored. Finally, ecosystem modelling and adaptive management responses are necessary to forecast and manage the benefits of HMRs. Moreover, uncertainty about the resolution of the well-rehearsed attraction/production debate may be resolved by ensuring that HMRs are managed as protected no-take areas. And to ensure an unbiased attitude that will aid the clarification of consequences, costs and benefits, we propose a change in terminology, from artificial reefs to human-made reefs.     

Management Strategies of Free-Roaming Horses in Alberta Compared with Other Jurisdictions

Management strategies of free-roaming species are subject to polarizing debates around the world. This paper provides perspectives on free-roaming horse management strategies practiced in Alberta and compares them against national management strategies used in Canada and internationally (United States and Australia) to illustrate importance of science-based and socially inclusive management schemes. Owing to their pluralistic status as an introduced and culturally significant species of western Canada, free-roaming horse populations are a contentious environmental management issue in Alberta. Some stakeholders (e.g., indigenous people, horse and animal rights advocates) believe the government aims to extirpate free-roaming horses in favor of cattle grazing. However, the Albertan government and ranchers believe it is important to conserve and manage free-roaming horse populations for all land users while minimizing adverse environmental effects in sensitive foothill and mountain grasslands and associated riparian areas in Alberta. Despite this contention, a systematic approach that is mindful of the history and cultural value of horses to society is required to properly manage this species. Best management practices from case studies were used to compare against four main concerns identified from the literature of free-roaming horse management used in Alberta. Concerns include 1) cultural heritage values, 2) free-roaming (or wild) horse designation, 3) lack of scientifically rigorous population monitoring, and 4) societal considerations. Ecological effects of free-roaming horses and human dimensions of their management are discussed. It is recommended that lessons learned from other jurisdictions be applied to free-roaming horse management in Alberta to provide a more holistic framework as the government develops a “feral horse management strategy.”     

Bonded sealants for fractured teeth

Dental fractures in veterinary patients are relatively common. Historically, very little treatment has been provided for these fractures. Because of the relatively thin layer of enamel present in canine and feline dentition, most fractures result in exposure of dentin and/or pulp. This article discusses the rationale and procedure for treatment of exposed dentin in vital (live) teeth. Correct case selection and treatment improve patient comfort and help decrease the chance of future endodontic involvement in these teeth. This procedure may be considered an entry-level restorative procedure. Once mastered, the materials and principles will allow the practitioner to branch into more sophisticated restorative procedures, such as composite restorations, auto-incline planes, and restoration of endodontic access sites.     

Surface quality sensing of trembling aspen (Populus tremuloides Michx.) veneer products by near infrared spectroscopy

Abstract

The potential of near infrared spectroscopy (NIRS) to estimate wood moisture content (MC), surface energy characteristics and adhesive bond strength were evaluated on aspen (Populus tremuloides Michx.) veneer subjected to different drying times. For samples dried progressively at 103°C, the best MC prediction model was for the total MC range (0–100%) with an R² value of 0.68. However, exposure at 180°C produced surface colour changes, and the CIE L*a*b* colour parameters measuring colour changes were better estimated using the 400–900 nm spectral data than the 1100–2400 nm spectral data. Increased exposure time at 180°C resulted in lower wettability and, hence, larger contact angles, especially when ethylene glycol was used as probe solvent. Lap shear strength tests on veneers showed that adhesion by phenol formaldehyde resins was impaired by the high temperature exposure; however, the lap shear strength test had high variability so there was not always a clear relationship between contact angle and lap shear strength test.     

Geographical classification of honey samples by near-infrared spectroscopy: a feasibility study

The potential of near-infrared (NIR) spectroscopy to determine the geographical origin of honey samples was evaluated. In total, 167 unfiltered honey samples (88 Irish, 54 Mexican, and 25 Spanish) and 125 filtered honey samples (25 Irish, 25 Argentinean, 50 Czech, and 25 Hungarian) were collected. Spectra were recorded in transflectance mode. Following preliminary examination by principal component analysis (PCA), modeling methods applied to the spectral data set were partial least-squares (PLS) regression and soft independent modeling of class analogy (SIMCA); various pretreatments were investigated. For unfiltered honey, best SIMCA models gave correct classification rates of 95.5, 94.4, and 96% for the Irish, Mexican, and Spanish samples, respectively; PLS2 discriminant analysis produced a 100% correct classification for each of these honey classes. In the case of filtered honey, best SIMCA models produced correct classification rates of 91.7, 100, 100, and 96% for the Argentinean, Czech, Hungarian, and Irish samples, respectively, using the standard normal variate (SNV) data pretreatment. PLS2 discriminant analysis produced 96, 100, 100, and 100% correct classifications for the Argentinean, Czech, Hungarian, and Irish honey samples, respectively, using a second-derivative data pretreatment. Overall, while both SIMCA and PLS gave encouraging results, better correct classification rates were found using PLS regression.     

Pigments in avocado tissue and oil

Pigments are important contributors to the appearance and healthful properties of both avocado fruits and the oils extracted from these fruits. This study determined carotenoid and chlorophyll pigment concentrations in the skin and three sections of the flesh (outer dark green, middle pale green, and inner yellow flesh-nearest the seed) and anthocyanin concentrations in the skin of Hass avocado during ripening at 20 degrees C. Pigments were extracted from frozen tissue with acetone and measured using high-performance liquid chromatography. Pigments were also measured in the oil extracted from freeze-dried tissue sections by an accelerated solvent extraction system using hexane. Carotenoids and chlorophylls identified in the skin, flesh, and oil were lutein, alpha-carotene, beta-carotene, neoxanthin, violaxanthin, zeaxanthin, antheraxanthin, chlorophylls a and b, and pheophytins a and b with the highest concentrations of all pigments in the skin. Chlorophyllides a and b were identified in the skin and flesh tissues only. As the fruit ripened and softened, the skin changed from green to purple/black, corresponding to changes in skin hue angle, and a concomitant increase in cyanidin 3-O-glucoside and the loss of chlorophyllide a. In flesh tissue, chroma and lightness values decreased with ripening, with no changes in hue angle. The levels of carotenoids and chlorophylls did not change significantly during ripening. As fruit ripened, the total chlorophyll level in the oil from the flesh sections remained constant but declined in the oil extracted from the skin.     

The impact of significant earthquakes on Christchurch,New Zealand's urban forest

The resilience of Christchurch, New Zealand's urban forest has been tested during a year of major earthquakes and aftershocks. Tree loss has resulted from mass soil movement, soil liquefaction, rockfalls, and land slips. At the time of writing, only 384 trees have been documented as removed, however, thousands more are scheduled for removal. Additionally, the changes to the soil environment resulting from liquefaction will require existing trees to adapt quickly to their new soil environment. Their fate will not be known for years. Though the total number of trees removed is unlikely to reduce city-wide canopy cover appreciably, it is important to recognize that spatial patterns of tree loss were highly localized and thus local canopy cover has been drastically reduced in some areas. Short-term management of the urban forest in the aftermath of the earthquake focused on removal of trees deemed unstable or unsafe. In the medium-term, attempts have been made to monitor the health and stability of remaining trees using an asset management system, though some difficulties related to consistency and ubiquity of its use have been identified. Though short and medium-term management have been largely effective, long-term management of Christchurch's urban forests will largely be dictated by government policy, which will be informed by public consultation and land ownership. Many of the benefits provided by urban forests are well understood. However, trees and greenspaces provided additional benefits during earthquakes and in the aftermath. Planted trees in the hills surrounding the city prevented rockfall from damaging infrastructure and human life downslope, while greenspaces were used as a base for search and rescue staff during rescue and recovery operations, and as temporary living spaces for residents who lost their homes.