MIMAC : Detection of low energy recoils for Dark Matter search

The MIMAC project is based on a matrix of Micro Time Projection Chambers (micro-TPC) for Dark Matter search, filled with He3 or CF4 and using ionization and tracks. The first measurement of the energy resolution of this micro-TPC is presented as well as its low thresholdComment: Dark Energy and Dark Matter conference, Lyon : France (2008

Pre-primary children\u27s progress and the school development plan

In recent years several policy changes have occurred in Western Australia regarding the provision of pre-compulsory education, particularly for children turning five. These changes have led to education of such children centred largely in full-time, on-site classes rather than in sessional, independent community centres, resulting in pre-primary education becoming mainstream school business. As such it is incorporated in the administrative, managerial and educational policies of the school including school development planning. The school development plan (SDP), a major tool of accountability within the school, provides a planning framework in selected priority areas in which methods of assessment and evaluation of children\u27s progress are an important tool in demonstrating that accountability. There is a concern among some pre-primary teachers and Early Childhood Education specialists that these changes may lead to a trend towards practices more indicative of upper primary school levels, known as a \u27push down\u27 effect, on pre-primary classes. There is also a concern that an emphasis on assessment and evaluation for accountability purposes may lead to a decline in the use of assessment data in classroom planning. This qualitative study examined how and why teachers in selected Perth metropolitan pre-primary classes gathered and recorded information on children\u27s progress, and how these choices related to the teacher\u27s responsibility as articulated in the school development plan. The study also identified how that information was used both at class and school levels

Lexical Influences on Spoken Spondaic Word Recognition in Hearing-Impaired Patients.

Top-down contextual influences play a major part in speech understanding, especially in hearing-impaired patients with deteriorated auditory input. Those influences are most obvious in difficult listening situations, such as listening to sentences in noise but can also be observed at the word level under more favorable conditions, as in one of the most commonly used tasks in audiology, i.e., repeating isolated words in silence. This study aimed to explore the role of top-down contextual influences and their dependence on lexical factors and patient-specific factors using standard clinical linguistic material. Spondaic word perception was tested in 160 hearing-impaired patients aged 23-88 years with a four-frequency average pure-tone threshold ranging from 21 to 88 dB HL. Sixty spondaic words were randomly presented at a level adjusted to correspond to a speech perception score ranging between 40 and 70% of the performance intensity function obtained using monosyllabic words. Phoneme and whole-word recognition scores were used to calculate two context-influence indices (the j factor and the ratio of word scores to phonemic scores) and were correlated with linguistic factors, such as the phonological neighborhood density and several indices of word occurrence frequencies. Contextual influence was greater for spondaic words than in similar studies using monosyllabic words, with an overall j factor of 2.07 (SD = 0.5). For both indices, context use decreased with increasing hearing loss once the average hearing loss exceeded 55 dB HL. In right-handed patients, significantly greater context influence was observed for words presented in the right ears than for words presented in the left, especially in patients with many years of education. The correlations between raw word scores (and context influence indices) and word occurrence frequencies showed a significant age-dependent effect, with a stronger correlation between perception scores and word occurrence frequencies when the occurrence frequencies were based on the years corresponding to the patients' youth, showing a "historic" word frequency effect. This effect was still observed for patients with few years of formal education, but recent occurrence frequencies based on current word exposure had a stronger influence for those patients, especially for younger ones

Potential for wind erosion as affected by management in bean-potato rotations

Non-Peer ReviewedThe potential for soil erosion in the bean phase of bean-potato rotations is significant due to low levels of crop residue following potatoes and the effect of management on soil structure particularly in light textured soils typical of the potato growing area of Manitoba. This potential can be mitigated by fall cover crops, application of straw or composted manure. In a study at Carberry, MB crop residue cover from 2000 to 2004, the proportion of small erodible aggregates and stability of aggregates were measured in treatments with fall applied cereal, fall applied compost, and spring applied polymer. Crop residue cover, proportion of erodible aggregates and aggregate stability were not consistently affected by management over the short term. In some years application of cereal residue in the fall increased residue cover, reduced the proportion of small erodible aggregates (<0.5 mm) and increased stability of aggregates. Application of polyacrylamide did not affect stability of wet-sieved aggregates but decreased the proportion of small aggregates (<0.5 mm) in 2002. Further research is required to assess the long-term impact of management on potential for wind erosion and properties of soil aggregates in bean-potato rotations

Effect of rotation and short-term tillage on soil quality after long-term zero tillage

Non-Peer ReviewedA field study was established in 2000, near Brandon Manitoba, to determine the effect of tillage and crop on soil physical and biological properties. Most soil physical and biological properties were not affected by tillage system or current year crop when sampled in the fall after harvest. The proportion of large (38 to 68.8 mm diameter) dry sieved aggregates increased under low compared to high intensities of tillage. Aggregate stability increased with increasing concentration of organic carbon. The effect of high and low intensity tillage over one or two years, after 9 years in zero tillage, on soil organic carbon, physical properties and fertility was not significant

MIMAC : a micro-TPC detector for non-baryonic dark matter search

The MIMAC project is multi-chamber detector for Dark Matter search, aiming at measuring both track and ionization with a matrix of micromegas micro-TPC filled with He3 and CF4. Recent experimental results on the first measurements of the Helium quenching factor at low energy (1 keV recoil) are presented.Comment: 7 pages, Proc of Dark Energy and Dark Matter conference, Lyon : France (2008

X-ray Crystallographic Characterization of the Co(II)-substituted Tris-bound Form of the Aminopeptidase from \u3cem\u3eAeromonas proteolytica\u3c/em\u3e

The X-ray crystal structure of the Co(II)-loaded form of the aminopeptidase from Aeromonas proteolytica ([CoCo(AAP)]) was solved to 2.2 Å resolution. [CoCo(AAP)] folds into an α/β globular domain with a twisted β-sheet hydrophobic core sandwiched between α-helices, identical to [ZnZn(AAP)]. Co(II) binding to AAP does not introduce any major conformational changes to the overall protein structure and the amino acid residues ligated to the dicobalt(II) cluster in [CoCo(AAP)] are the same as those in the native Zn(II)-loaded structure with only minor perturbations in bond lengths. The Co(II)–Co(II) distance is 3.3 Å. Tris(hydroxymethyl)aminomethane (Tris) coordinates to the dinuclear Co(II) active site of AAP with one of the Tris hydroxyl oxygen atoms (O4) forming a single oxygen atom bridge between the two Co(II) ions. This is the only Tris atom coordinated to the metals with Co1–O and Co2–O bonds distances of 2.2 and 1.9 Å, respectively. Each of the Co(II) ions resides in a distorted trigonal bipyramidal geometry. This important structure bridges the gap between previous structural and spectroscopic studies performed on AAP and is discussed in this context

Potential for wind erosion in alternative cropping systems

Non-Peer ReviewedThe potential for wind erosion in agricultural soils is a function of the distribution of aggregates at the surface, soil structure and moisture, and crop residue. These properties were measured in a cropping systems study designed to determine the effect of input level and crop diversity on sustainability and the potential for wind erosion. The experiment was established on a sandy loam soil in the Dark Brown Soil Zone at Scott Saskatchewan. Input levels were organic, reduced and high, while cropping-diversity levels were low diversity, diverse annual and diverse annual perennial. Differences in residue were attributed to the effect of tillage and the relative levels of productivity in the systems. Spring and fall tillage in organic systems reduced the amount of residue compared to reduced input systems. Levels of crop residue were low at the beginning of this study, and crop residue cover should be measured in future years to determine potential for erosion. Crop residue levels may not reflect the system's potential for soil erosion until two rotation cycles are complete. Relative treatment differences observed in the study, were similar to those calculated with of the Douglas-Rickman decomposition equation and tillage coefficients

Rapid assessment of soil salinity

Non-Peer Reviewe