éditorial.

In this editorial, Peter Dixon expresses what a great honour it is to him to take on the editorship of the Canadian Journal of Experimental Psychology. He further remarks that the Journal has a long tradition of scientific excellence and rigour that he intends to uphold and foster. Dixon goes on to discuss various aspects of the Journal's nature, and also touches upon a few topics about the Journal's editorial policies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

TERRA COTTA KILN SLAB INVESTIGATION1

Following several discussions as to the constitution of a good kiln slab for terra cotta manufacture, a coöperative test was made in which slabs of various compositions were manufactured by a producer of refractories, tested under actual service conditions, and physical measurements were determined by the Ceramic Department, Rutgers University. Series included the use of tight-firing medium refractory clays, open-firing refractory clays with grog, both vitreous and porous. Grogs were sized (definite proportions of size ranges constituting the different members). Conclusions were drawn as to effect of all these variables.     

Economic analysis of water temperature reduction practices in a large river floodplain: an exploratory study of the Willamette River,Oregon

This paper examines ecosystem restoration practices that focus on water temperature reductions in the upper mainstem Willamette River, Oregon, for the benefit of endangered salmonids and other native cold‐water species. The analysis integrates hydrologic, natural science and economic models to determine the cost‐effectiveness of alternative water temperature reduction strategies. A temperature model is used to simulate the effects of combinations of upstream riparian shading and flow augmentations on downstream water temperatures. Costs associated with these strategies are estimated and consist of the opportunity costs of lost agricultural production and recreation opportunities due to flow releases from an up‐stream reservoir. Temperature reductions from another strategy, hyporheic flow enhancement, are also examined. Restoration strategies associated with enhanced hyporheic cooling consist of removal/reconnection of current obstacles to the creation of dynamic river channel complexity. The observed reduction of summer water temperatures associated with enhanced channel complexity indicates that restoring hyporheic flow processes is more likely to achieve cost‐effective temperature reductions and meet the total maximum daily load (TMDL) target than conventional approaches that rely on increased riparian shading or/and combinations of flow augmentation. Although the costs associated with the hyporheic flow enhancement approach are substantial, the effects of such a long‐term ecological improvement of the floodplain are expected to assist the recovery of salmonid populations and provide ancillary benefits to society. Copyright © 2008 John Wiley & Sons, Ltd.     

创意自然

<正>当今,人类与自然不和谐、不符合自然规律的关系普遍存在。从农业砍伐森林、筑坝发电,到工业污染物充斥的空气,这些互动往往意味着破坏。即使破坏性的干预措施被更富有创意的措施取代,这种不和谐仍然存在。     

Concentration and distribution of heavy metals in urban airborne particulate matter in Frankfurt am Main, Germany

Heavy metal concentrations were measured in airborne dust collected at three sites with different traffic densities from August 2001 to July 2002 in the Frankfurt am Main area. Bulk samples of particulate matter (PM) with an aerodynamic equivalent diameter of <22 microm were collected on cellulose nitrate filters using air filtration devices. Fractionated samples of PM with an aerodynamic equivalent diameter of <10 microm were collected using an eight-stage Andersen impactor. Pb, Cd, Mn, Ni, Zn, V, As, Sb, Cu, Cr, Co, and Ce were determined by inductively coupled plasma sector field mass spectrometry, Pt and Rh were determined by adsorptive voltammetry, and Pd was determined by total reflection X-ray fluorescence analysis. The results show that the highest airborne heavy metal concentrations occurred at the main street with a large volume of traffic. With the exception of Co, V, Ce, and Mn, the heavy metals had an elevated enrichment factor compared to their concentrations in the continental crust. The main street site was especially contaminated with Sb, Zn, Cu, V, and Ni. Motor vehicles are the likely source of emissions. With the exception of Cr, Cu, and Zn, most of the airborne heavy metal concentrations determined for impactor samples deviate slightly from the results for total airborne dust. Heavy metal particle size distributions can be divided into three groups. For metals such as As, Cd, Pb, and V, the main fraction can be found in fine particles with a diameter of <2.1 microm, whereas Ce, Cr, Co, and Ni occur mainly in coarse particles with a diameter of >2.1 microm. Cu, Mn, Sb, Zn, Pt, Pd, and Rh occur in high concentrations in the medium range of the impactor stages (particle diameters of 1.1-4.7 microm). Metal concentrations in fine dust particles are needed to assess the human health risks of their inhalation.     

Atomic force microscopy of the morphology and mechanical behaviour of barnacle cyprid footprint proteins at the nanoscale

Barnacles are a major biofouler of man-made underwater structures. Prior to settlement, cypris larvae explore surfaces by reversible attachment effected by a ‘temporary adhesive’. During this exploratory behaviour, cyprids deposit proteinaceous ‘footprints’ of a putatively adhesive material. In this study, footprints deposited by Balanus amphitrite cyprids were probed by atomic force microscopy (AFM) in artificial sea water (ASW) on silane-modified glass surfaces. AFM images obtained in air yielded better resolution than in ASW and revealed the fibrillar nature of the secretion, suggesting that the deposits were composed of single proteinaceous nanofibrils, or bundles of fibrils. The force curves generated in pull-off force experiments in sea water consisted of regions of gradually increasing force, separated by sharp drops in extension force manifesting a characteristic saw-tooth appearance. Following the relaxation of fibrils stretched to high strains, force–distance curves in reverse stretching experiments could be described by the entropic elasticity model of a polymer chain. When subjected to relaxation exceeding 500 ms, extended footprint proteins refolded, and again showed saw-tooth unfolding peaks in subsequent force cycles. Observed rupture and hysteresis behaviour were explained by the ‘sacrificial bond’ model. Longer durations of relaxation (>5 s) allowed more sacrificial bond reformation and contributed to enhanced energy dissipation (higher toughness). The persistence length for the protein chains (L_P) was obtained. At high elongation, following repeated stretching up to increasing upper strain limits, footprint proteins detached at total stretched length of 10 µm.