Children's construction task performance and spatial ability: controlling task complexity and predicting mathematics performance.

This paper presents a methodology to control construction task complexity and examined the relationships between construction performance and spatial and mathematical abilities in children. The study included three groups of children (N = 96); ages 7-8, 10-11, and 13-14 years. Each group constructed seven pre-specified objects. The study replicated and extended previous findings that indicated that the extent of component symmetry and variety, and the number of components for each object and available for selection, significantly predicted construction task difficulty. Results showed that this methodology is a valid and reliable technique for assessing and predicting construction play task difficulty. Furthermore, construction play performance predicted mathematical attainment independently of spatial ability

A global map to aid the identification and screening of critical habitat for marine industries

Marine industries face a number of risks that necessitate careful analysis prior to making decisions on the siting of operations and facilities. An important emerging regulatory framework on environmental sustainability for business operations is the International Finance Corporation’s Performance Standard 6 (IFC PS6). Within PS6, identification of biodiversity significance is articulated through the concept of “Critical Habitat”, a definition developed by the IFC and detailed through criteria aligned with those that support internationally accepted biodiversity designations. No publicly available tools have been developed in either the marine or terrestrial realm to assess the likelihood of sites or operations being located within PS6-defined Critical Habitat. This paper presents a starting point towards filling this gap in the form of a preliminary global map that classifies more than 13 million km2 of marine and coastal areas of importance for biodiversity (protected areas, Key Biodiversity Areas [KBA], sea turtle nesting sites, cold- and warm-water corals, seamounts, seagrass beds, mangroves, saltmarshes, hydrothermal vents and cold seeps) based on their overlap with Critical Habitat criteria, as defined by IFC. In total, 5798×103 km2 (1.6%) of the analysis area (global ocean plus coastal land strip) were classed as Likely Critical Habitat, and 7526×103 km2 (2.1%) as Potential Critical Habitat; the remainder (96.3%) were Unclassified. The latter was primarily due to the paucity of biodiversity data in marine areas beyond national jurisdiction and/or in deep waters, and the comparatively fewer protected areas and KBAs in these regions. Globally, protected areas constituted 65.9% of the combined Likely and Potential Critical Habitat extent, and KBAs 29.3%, not accounting for the overlap between these two features. Relative Critical Habitat extent in Exclusive Economic Zones varied dramatically between countries. This work is likely to be of particular use for industries operating in the marine and coastal realms as an early screening aid prior to in situ Critical Habitat assessment; to financial institutions making investment decisions; and to those wishing to implement good practice policies relevant to biodiversity management. Supplementary material (available online) includes other global datasets considered, documentation and justification of biodiversity feature classification, detail of IFC PS6 criteria/scenarios, and coverage calculations

Electrophysiological correlates of high-level perception during spatial navigation

We studied the electrophysiological basis of object recognition by recording scalp\ud electroencephalograms while participants played a virtual-reality taxi driver game.\ud Participants searched for passengers and stores during virtual navigation in simulated\ud towns. We compared oscillatory brain activity in response to store views that were targets or\ud nontargets (during store search) or neutral (during passenger search). Even though store\ud category was solely defined by task context (rather than by sensory cues), frontal ...\ud \u

Retarded long-range potentials for the alkali-metal atoms and a perfectly conducting wall

The retarded long-range potentials for hydrogen and alkali-metal atoms in their ground states and a perfectly conducting wall are calculated. The potentials are given over a wide range of atom-wall distances and the validity of the approximations used is established.Comment: RevTeX, epsf, 11 pages, 2 fig

Prevalence and severity of cardiac abnormalities and arteriosclerosis in farmed rainbow trout (Oncorhynchus mykiss)

Cardiovascular disease may pose a major threat to the health and welfare of farmed fish. By investigating a range of established cardiovascular disease indicators, we aimed to determine the prevalence, severity and consequences of this affliction in farmed rainbow trout (Oncorhynchus mykiss) from an open cage farm in the Baltic Sea, an open cage farm in a freshwater lake, and a land-based recirculating aquaculture system. We also aimed to identify environmental, anthropogenic and physiological factors contributing towards the development of the disease. The majority of trout possessed enlarged hearts with rounded ventricles (mean height:width ratios of 1.0-1.1 c.f. similar to 1.3 in wild fish) and a high degree of vessel misalignment (mean angles between the longitudinal ventricular axis and the axis of the bulbus arteriosus of 28-31 degrees c.f. similar to 23 degrees in wild fish). The prevalence and severity of coronary arteriosclerosis was also high, as 92-100% of fish from the different aquaculture facilities exhibited coronary lesions. Mean lesion incidence and severity indices were 67-95% and 3.1-3.9, respectively, which resulted in mean coronary arterial blockages of 19-32%. To evaluate the functional significance of these findings, we modelled the effects of arterial blockages on coronary blood flow and experimentally tested the effects of coronary occlusion in a sub-sample of fish. The observed coronary blockages were estimated to reduce coronary blood flow by 34-54% while experimental coronary occlusion adversely affected the electrocardiogram of trout. Across a range of environmental (water current, predation), anthropogenic (boat traffic intensity, hatchery of origin, brand of feed pellets) and physiological factors (condition factor, haematological and plasma indices), the hatchery of origin was the main factor contributing towards the observed variation in the development of cardiovascular disease. Therefore, further research on the effects of selective breeding programs and rearing strategies on the development of cardiovascular disease is needed to improve the welfare and health of farmed fish

Exclusive Measurements of pp -> dpi+pi0: Double-Pionic Fusion without ABC Effect

Exclusive measurements of the reaction pp -> dpi+pi0 have been carried out at T_p = 1.1 GeV at the CELSIUS storage ring using the WASA detector. The isovector pi+pi0 channel exhibits no enhancement at low invariant pipi masses, i. e. no ABC effect. The differential distributions are in agreement with the conventional t-channel Delta-Delta excitation process, which also accounts for the observed energy dependence of the total cross section. This is an update of a previously published version -- see important note at the end of the article

Momentum transfer using chirped standing wave fields: Bragg scattering

We consider momentum transfer using frequency-chirped standing wave fields. Novel atom-beam splitter and mirror schemes based on Bragg scattering are presented. It is shown that a predetermined number of photon momenta can be transferred to the atoms in a single interaction zone.Comment: 4 pages, 3 figure