The extreme xerophilic mould Xeromyces bisporus--growth and competition at various water activities

Little is known about the mould, Xeromyces bisporus, unique in its strong xerophilicity and ability to grow at water activity (a_w) 0.62, lower than for any other known organism. The linear growth rates of one fast and one slow-growing strain of X. bisporus were assessed at 20, 25, 30 and 37 °C on solid agar media containing a mixture of glucose and fructose to reduce a_w to 0.94, 0.88, 0.84, 0.80, 0.76 and 0.66. Growth rates of xerophilic species closely related to X. bisporus, viz. Chrysosporium inops, C. xerophilum and Monascus eremophilus, were also assessed. Optimal conditions for growth of both X. bisporus strains were approx. 0.84 a_w and 30 °C, despite FRR 2347 growing two- to five-fold faster than CBS 185.75. X. bisporus FRR 2347 even grew well at 0.66 a_w (0.48 mm/day). C. inops and C. xerophilum were more tolerant of high a_w than X. bisporus, and could be differentiated from each other based on: the faster growth of C. xerophilum; its preference for temperatures ≥ 30 °C and a_w ≥ 0.94 (c.f. ≤ 25 °C and ~ 0.88 a_w for C. inops); and its ability to grow at 0.66 a_w, which is the lowest a_w reported to date for this species. M. eremophilus grew slowly (max. 0.4 mm/day) even in its optimal conditions of ~ 0.88 a_w and 25 °C. To investigate the competitive characteristics of X. bisporus at low a_w, both X. bisporus strains were grown in dual-culture with xerotolerant species Aspergillus flavus and Penicillium roqueforti, and xerophilic species A. penicillioides, C. inops, C. xerophilum and Eurotium chevalieri, on glucose-fructose agar plates at 0.94, 0.84, 0.80 and 0.76 a_w and at 25 °C. Growth rates and types of interactions were assessed. Excretion of inhibitory substances acting over a long-range was not observed by any species; inhibitors acting over a short-range that temporarily slowed competitors' growth or produced a protective zone around the colony were occasionally observed for A. penicillioides, C. inops and C. xerophilum. Instead, rapid growth relative to the competitor was the most common means of dominance. The xerotolerant species, A. flavus and P. roqueforti were dominant over X. bisporus at 0.94 a_w. E. chevalieri was often dominant due to its rapid growth over the entire a_w range. At a_w < 0.80, X. bisporus was competitive because it grew faster than the other species examined. This supports the concept that its ideal environmental niche is sugary foods with low a_w.     

Longitudinal stability of temperamental exuberance and social–emotional outcomes in early childhood.

The goals of the current study were to investigate the stability of temperamental exuberance across infancy and toddlerhood and to examine the associations between exuberance and social–emotional outcomes in early childhood. The sample consisted of 291 4-month-olds followed at 9, 24, and 36 months and again at 5 years of age. Behavioral measures of exuberance were collected at 9, 24, and 36 months. At 36 months, frontal electroencephalogram (EEG) asymmetry was assessed. At 5 years, maternal reports of temperament and behavior problems were collected, as were observational measures of social behavior during an interaction with an unfamiliar peer in the laboratory. Latent profile analysis revealed a high, stable exuberance profile that was associated with greater ratings of 5-year externalizing behavior and surgency, as well as observed disruptive behavior and social competence with unfamiliar peers. These associations were particularly true for children who displayed left frontal EEG asymmetry. Multiple factors supported an approach bias for exuberant temperament but did not differentiate between adaptive and maladaptive social–emotional outcomes at 5 years of age. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A new approach for the characterization of the pore structure of dual porosity rocks

For the realistic representation of the pore space of dual porosity rocks, a new method of pore structure characterization is developed by combining experimental Hg intrusion/retraction curves with back-scattered scanning electron microscope (BSEM) images and inverse modeling algorithms. The pore space autocorrelation function measured by processing the digitized BSEM images is combined with the surface fractal dimension estimated from the high pressure Hg intrusion (MIP) data to derive a synthetic small-angle neutron scattering (SANS) intensity function, the inversion of which provides a volume-based pore body radius distribution (PBRD). The volume-based PBRD is fitted with a multimodal number-based PBRD consisting of two component distributions: one representing the macroporosity and another one representing the microporosity. Based on arguments of percolation theory, analytical mathematical models are developed to describe the Hg intrusion in and retraction from dual pore networks in terms of the complete PBRD, pore throat radius distribution (PTRD) of macroporosity, drainage accessibility functions (DAFs) of both porosities, and imbibition accessibility functions (IAFs) of both porosities. Inverse modeling of the Hg intrusion data set enables us to estimate the PTRD and DAFs. Inverse modeling of the Hg retraction datasets enables us to estimate a set of primary and secondary IAFs. The method is demonstrated by the pore structure characterization of four outcrop samples of carbonate and sandstone rocks. Analytic approximate equations developed from the critical path analysis (CPA) of percolation theory enable us to calculate explicitly the absolute permeability and the formation factor of the porous rocks using the estimated parameters (PBRD, PTRD, DAF) of the macroporosity. The measured permeability of cores is predicted satisfactorily and observed discrepancies may be attributed to large length-scale macro-heterogeneities which are not evident in BSEM images and Hg porosimetry data.     

MAKING VISIBLE

This article analyses recent photographic practices that make visible underlying realities faced by Western societies today as they struggle to reconcile contradictions between their policies on race, immigration and ethnicity and the quest for an integrated national identity. The main case studies are drawn from the works of Mohamed Bourouissa and Tobias Zielony. The article demonstrates how their photographic projects confront the logic of social and cultural marginalisation of the immigrant communities, which often overlaps with their spatial consignment to urban peripheries. By combining reality and fiction, symbolism and documentation, these projects offer alternatives to the modes of representation available in photojournalism, as well as re-connecting with the genre of street photography.     

Occupational segregation in a country of recent mass immigration: evidence from Spain

The aim of this paper is to study the occupational segregation of immigrants in Spain. It analyzes whether age, educational level, gender, region of origin, and years of residence in Spain affect the distribution of immigrants across occupations. In addition, given the remarkable increase of immigrants in the last few years and the adjustments that have occurred in the Spanish labor market from the current economic crisis, the evolution of the occupational segregation of immigrants between 1996 and 2009 is addressed. For these purposes, several measures recently proposed in the literature are used.     

Effects of optical radiation on the Mössbauer spectrum of 151Eu3+: CaF2

We study the changes in the shape of the Mössbauer spectrum for the 21.5?keV transition of ¹⁵¹Eu³⁺ nuclei in a CaF₂ lattice, assuming that a population of the excited electronic state ⁵ D ₀ is maintained by optical pumping. For a population of the excited state ⁵ D ₀ of 10%, we determine the magnitude of the changes in the Mössbauer spectrum as 1.9% of the area of the unperturbed spectrum.     

3D reconstruction of cultural heritages: Challenges and advances on precise mesh integration

Several methods perform the integration of multiple range scans of an object aiming the generation of a reconstructed triangle mesh; however, achieving high fidelity digital reconstructions is still a challenge. That is mostly due to the existence of outliers in the acquired range data, and their harmful effects on the integration algorithms. In this work, we first discuss artifacts usually found on real range data captured with 3D scanners based on laser triangulation. Following that there is the assessment of two widely used volumetric integration techniques (VRIP and Consensus Surface) and our suggested improvements. We also present a novel, hybrid approach that combines strengths from both VRIP and Consensus Surface, named IMAGO Volumetric Integration Algorithm (IVIA). Our novel algorithm adds new ideas while improving the detection and elimination of artifacts. Further, IVIA works in close cooperation with the subsequent hole filling process, which greatly improves the overall quality of the generated 3D models. Our technique leads to better results when assessed in different situations, when compared to VRIP, Consensus Surface, and also to a well known state-of-the-art surface-based method, Poisson Surface Reconstruction.     

Lunar Habitat Micrometeoroid and Radiation Shielding: Options, Applications, and Assessments

Various shielding approaches to protect lunar habitats from micrometeoroid and radiation hazards present major trade-off considerations. Popular scenarios that envision covering modules with in situ regolith will necessitate means to excavate and move large amounts of material; will complicate evolutionary outpost growth; and may require long tunnels between connecting pressurized elements. Strategies that incorporate shielding materials into module structures or internal shelters add very substantial launch mass penalties. Utilization of water bladders can make efficient use of consumable/recyclable supplies, but may impose excess capacity deliveries at early development stages. This paper addresses these different shielding approaches from a top-level application perspective, highlighting pros and cons of each. Examples draw upon research and design investigations undertaken by the Sasakawa International Center for Space Architecture in support of separate National Aeronautics and Space Administration (NASA) contracts awarded to teams headed by Boeing and ILC-Dover for a “Minimum Functionality Habitation Systems Concept Study.” Comprehensive team study results were presented to NASA in February 2009, and have been released as public information.     

Novel Use of Kaolin Wastes in Blended Cements

This paper describes the influence of different thermally activated clay wastes (ACW) on the hydration phases in cement pastes containing two percentages of addition (10% and 20%). Results show that the main products obtained during hydration of cement pastes containing ACW were portlandite, calcium aluminate hydrates, calcium silicate hydrates, and hydrotalcite-type compounds. Portlandite formation decreases when addition percentage is 20%, contrary to tetracalcium aluminate hydrate, which increases in similar conditions. The ACW that showed the most portlandite consumption was ACW1 (700°C, 2 h) according to thermogravimetric data.