Understanding of the concept of numerically "less" by bottlenose dolphins (Tursiops truncatus).

In 2 experiments, bottlenose dolphins (Tursiops truncatus) judged the ordinal relationship between novel numerosities. The dolphins were first trained to choose the exemplar with the fewer number of items when presented with just a few specific comparisons (e.g., 2 vs. 6, 1 vs. 3, and 3 vs. 7). Generalization of this rule was then tested by presenting the dolphins with all possible pairwise comparisons between 1 and 8. The dolphins chose the exemplar with the fewer number of items at levels far above chance, showing that they could recognize and represent numerosities on an ordinal scale. Their pattern of errors was consistent with the idea of an underlying analog magnitude representation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Size Dependence of the Ratio of Aerosol Coagulation to Deposition Rates for Indoor Aerosols

A thorough understanding of the importance of aerosol coagulation and deposition relative to each other as modifiers of the particle size distribution plays an important role in the proper selection of conditions to estimate the deposition rate coefficient. In this work, a theoretical analysis was conducted for investigating the size-resolved ratio of coagulation to deposition for different types of size distributions using the Simpson integral method. The theoretical model was subsequently qualitatively validated by experiments in a completely mixed and ventilated aerosol chamber. Both experimental and theoretical studies show that the ratio of the rates of coagulation to deposition is strongly dependent on the total particle number concentration and the geometric mean diameter of the aerosol. A variation of the ratio of coagulation to deposition by several orders of magnitude for aerosols with differing size distributions was found. Thus the previously employed criterion for the negligence of coagulation based solely on the total particle number concentration was shown to be insufficient to accurately judge whether an aerosol is suited for the estimation of the deposition rate coefficient. Aerosols with wide size distributions are not recommended for use in the estimation of the deposition rate coefficient. The study provides a method to understand the role of coagulation and deposition for indoor aerosols.

Copyright 2013 American Association for Aerosol Research     

Experimental Evidence for a New State in 2D Bose Gas: Quasi-Condensation in Atomic Hydrogen

We have obtained two-dimensional (2D) Bose gas with the degeneracy parameter (phase-space density) up to 9 compressing magnetically atomic hydrogen adsorbed on liquid ⁴ He at about 0.2 K. We observed this 2D gas to go over to a state where the rate constant K _bbb of three-body recombination of hydrogen atoms decreases with respect to its normal value. A steep decline in K _bbb begins when the degeneracy parameter exceeds 3, i.e., before the criterion for 2D superfluidity is satisfied. The maximum observed suppresion of K _bbb is essentially larger than 3! predicted for a three-body process in a fully (quasi)condensed sample.     

Humidification and perceived indoor air quality in the office environment

The DNA content of 85 ductal breast cancers of different histological grades was evaluated using static cytometry and correlated with immunocytochemical expression of p53 protein in tumour cells in cytological material. A statistically significant difference was observed between p53 protein expression and grade of malignancy (P < 0.001). The percentage of euploid tumours significantly decreased from grade I through grade II to grade III tumours (P < 0.001). Clonal DNA heterogeneity was observed in 26.6% of cases analysed and was correlated with p53 protein expression (P < 0.001). These changes probably reflect genomic alterations which may affect potential malignancy of breast cancer.     

Mechanical Ventilation in Office Buildings and the Sick Building Syndrome. An Experimental and Epidemiological Study

The effects of mechanical ventilation on the sick building syndrome (SBS) were studied in an office building with 2150 employees, where the mechanical ventilation and indoor air quality were commonly blamed for causing symptoms typical of the SBS (nasal, eye, and mucous membrane symptoms, lethargy, skin symptoms and headache). The mechanical ventilation rates in the building were high (mean 26 l/s/person). To test the hypothesis that mechanical ventilation causes the SBS, a controlled experimental study was carried out by shutting off the ventilation in one part of the building and reducing the ventilation rate by 75% and 60% in two areas while leaving one part unaltered as a control. The experimental reduction of the ventilation rate did not alleviate the symptoms. On the contrary, the reduction of the ventilation rate caused a slight but statistically significant relative increase in symptoms (p < 0.05). In the cross-sectional analysis of the baseline data the SBS symptoms did not associate significantly with the ventilation rate (range 7–70 l/s/person). In the linear regression model, a positive correlation was found between temperatures above 22°C and the occurrence of symptoms (p < 0.05). Subjects exposed to environmental tobacco smoke had more symptoms than those not exposed (p < 0.01). Women reported more symptoms than men (p < 0.001). In addition, any prior history of allergic diseases (p < 0.001) and a negative attitude towards the social atmosphere at work (p < 0.001) were significant determinants of the SBS.     

Generation of urban road dust from anti-skid and asphalt concrete aggregates

Road dust forms an important component of airborne particulate matter in urban areas. In many winter cities the use of anti-skid aggregates and studded tires enhance the generation of mineral particles. The abrasion particles dominate the PM10 during springtime when the material deposited in snow is resuspended. This paper summarizes the results from three test series performed in a test facility to assess the factors that affect the generation of abrasion components of road dust. Concentrations, mass size distribution and composition of the particles were studied. Over 90% of the particles were aluminosilicates from either anti-skid or asphalt concrete aggregates. Mineral particles were observed mainly in the PM10 fraction, the fine fraction being 12% and submicron size being 6% of PM10 mass. The PM10 concentrations increased as a function of the amount of anti-skid aggregate dispersed. The use of anti-skid aggregate increased substantially the amount of PM10 originated from the asphalt concrete. It was concluded that anti-skid aggregate grains contribute to pavement wear. The particle size distribution of the anti-skid aggregates had great impact on PM10 emissions which were additionally enhanced by studded tires, modal composition, and texture of anti-skid aggregates. The results emphasize the interaction of tires, anti-skid aggregate, and asphalt concrete pavement in the production of dust emissions. They all must be taken into account when measures to reduce road dust are considered. The winter maintenance and springtime cleaning must be performed properly with methods which are efficient in reducing PM10 dust.     

The development of situational interest during a digital mathematics game

The present study focused on 212 fifth graders' situational interest trajectories during an intervention with a digital mathematics game called Number Navigation. Our aims were to explore the development of situational interest whilst playing the game and to investigate the relationship between situational interest and individual math interest. Growth mixture model analyses showed that in the whole sample situational interest was stable within sessions but decreased across sessions. Three different situational interest trajectories were found. Situational interest trajectories were predicted by pre‐test individual interest. In turn, situational interest had an effect on post‐test individual interest. Students whose situational interest trajectories were stable (either high or low) presented no changes in individual interest, yet the individual interest of students whose situational interest was triggered but not maintained markedly decreased from pre‐test to post‐test. Results suggest that it is important to use game‐based learning not because games are believed to be “motivating”; rather, games with proven learning outcomes should be carefully selected.     

Effect of industrial pollution on the distribution of 137Cs in soil and the soil-to-plant transfer in a pine forest in SW Finland

The objective of this study was to evaluate the effect of industrial pollution on the distribution of radiocaesium in soil and on its transfer from soil to plants. The study was started in September 2000 in four Scots pine stands located at distances of 0.5, 2, 4 and 8 km along a transect running SE from the Cu-Ni smelter at Harjavalta in SW Finland. Annual emissions from the smelter in 1990 were 80 t of Cu, 31 t of Ni and 9000 t of SO(2), and in 1999 these were 5.9, 0.8 and 3400 t, respectively. At each site, soil profiles were sampled with a corer, and samples were separated into litter (L), organic soil layer (O) and mineral soil layers (B, E). Mushrooms, lichens (Cladina spp. and Cetraria islandica), lingonberry (Vaccinium vitis-idaea) and crowberry (Empetrum nigrum) plants were collected at each site, except at a distance of 0.5 km, where only mushrooms were available. In the organic soil layer, 137Cs activity decreased from 8000 Bq/m(2) at a distance of 8 km from the smelter to 1500 Bq/m(2) at a distance of 0.5 km; in litter, 137Cs concentration increased from 6300 Bq/m(2) at 8 km to 14000 Bq/m(2) at 0.5 km. 137Cs activity concentration decreased significantly in plants, mushrooms and lichens as the pollution load increased. In lichens, 137Cs activity decreased from 910 Bq/kg at 8 km to 170 Bq/kg at 2 km, while in lingonberry it decreased from 1470 to 20 Bq/kg and in crowberry from 310 to 20 Bq/kg. Aggregated transfer factors for 137Cs decreased in a similar way in lingonberry from 7.6x10(-2) m(2)/kg at 8 km to 7.7x10(-4) m(2)/kg at 2 km and in crowberry from 1.6x10(-2) to 7.9x10(-4) m(2)/kg.     

Radiation resistance of MBE-grown GaInP/GaAs-based solar cells

Proton irradiation-based degradation characteristics for molecular beam epitaxy (MBE) grown Ga_0·51In_0·49P/GaAs single-junction tandem solar cells of n/p configuration are reported. The cells were irradiated with 3-MeV protons up to fluences of 10¹³ cm⁻². The cells were characterized with current–voltage (I–V) measurements at AMO conditions, and with spectral measurements. The damage coefficient for the GaAs cells was calculated using numerical modelling by the PC-1D program, and the result was compared with the InP damage coefficient. By using the ‘displacement damage dose’ approach, the degradation characteristics were compared with the published data for InP and GaAs/Ge solar cells. In addition, these MBE results were compared with the radiation behavior of metal-organic chemical vapor deposition (MOCVD)-grown Ga_0·51In_0·49P/GaAs single-, and double-junction solar cells of p/n configuration. © 1998 John Wiley & Sons, Ltd.