Mechanical Relaxation of a Ti_(36.2)Zr_(30.3)Cu_(8.3)Fe_4Be_(21.2) Bulk Metallic Glass: Experiments and Theoretical Analysis

The dynamic mechanical relaxation behavior of Ti_(36.2)Zr_(30.3)Cu_(8.3)Fe_4Be_(21.2) bulk metallic glass with good glass-forming ability was investigated by mechanical spectroscopy. The mechanical relaxation behavior was analyzed in the framework of quasi-point defects model. The experimental results demonstrate that the atomic mobility of the metallic glass is closely associated with the correlation factor χ. The physical aging below the glass transition temperature T g shows a non-Debye relaxation behavior, which could be well described by stretched Kohlrausch exponential equation. The Kohlrausch exponent β_(aging) reflects the dynamic heterogeneities of the metallic glass. Both concentration of "defects" and atomic mobility decrease caused by the in situ successive heating during the mechanical spectroscopy experiments.     

Restoration process of the need for autonomy: The early alarm stage.

Autonomy is described by self-determination theory as a basic psychological need, essential for individuals' well-being. While basic needs are generally thought to induce a restorative response when thwarted, evidence for such a process is lacking for autonomy. To date, most evidence indicates that autonomy deprivation leads to disaffection of this need in favor of other motives. A temporal model based on the general adaptation syndrome was adapted to reconcile this seeming contradiction. Specifically, it is hypothesized that an early alarm response aimed at restoring the satisfaction of the need for autonomy should precede the later relinquishment and compensation of this need that would result from a prolonged deprivation. Three studies provide support for this model by showing the existence of the immediate autonomy restorative response. Using a controlling situation to manipulate autonomy deprivation, the authors demonstrate in Experiments 1 and 2 that a controlling context leads to enhanced accessibility and an approach bias for autonomy-related stimuli. Experiment 3 indicates that the urge to restore autonomy can also affect personal judgment, leading individuals to make more independent judgments, exercising a nonreactive form of autonomy. Integration of this model within self-determination theory is discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Mechanochemical degradation of poly(vinyl fluoride) by sodium hydroxide measured by microindentation

The degradation of the mechanical properties of deformed PVDF during its mechanochemical ageing in sodium hydroxide (soda) was followed by microindentation measurements, especially the local reduction of the elastic modulus and the hardness. This allows measurements on a local scale of the mechanical properties on the surface and in-depth as a function of the strain level and the ageing time. Microindentation tests with Berkovich indenter have been performed with a Nanoindenter XP^® (MTS). Measurements are made at penetration depth less than 2 μm for an applied load of 10 mN. During ageing in soda (Ph 14) at 90 °C up to 16 days, various deformations ε (0, 22 and 38%) are imposed on PVDF tensile specimen. For the first two imposed deformations (ε = 0 and ε = 22%), mechanical degradation is limited to some percent (less than 7%). For the greatest deformation (ε = 38%), mechanical degradation continues to decrease with ageing time (more than 21%). Microindentation tests show that a range of low deformations exists in which the mechanochemical degradation is limited and no limitation is observed for larger imposed deformation.     

Harmonizing agriculture and health sector actions to improve household nutrition: policy experiences from Afghanistan (2002–2007)

Coordination across sectors to address undernutrition with its varied underlying causes remains a challenge in developing countries. In Afghanistan, harmonization of health and agriculture policies and actions to reduce endemic undernutrition occurred during 2002-2007. This qualitative case study explores the forms of harmonization, enabling features and constraints in the policy process. We interviewed 57 stakeholders (39 central level, 18 provincial) involved in public nutrition or food security issues. Forms of harmonization included written policies, reseach, training and advocacy. Important features of the policy process included: policy entrepreneurs with operational and strategic capacity, consensus-building using a shared causal framework, working groups and strategic alliances. This case presents an interesting alternative to a national nutrition coordinating body, an approach that has met with mixed results, often due to the lack of authority, budget, and operational capacity of such a body to oversee ministries and enforce national nutrition objectives. Mid-level professionals mobilized into task forces achieved much with the support of national and international partners. This study highlights the importance of building capacity for sustaining change through local institutions.     

On calorimetric study of the fragility in bulk metallic glasses with low glass transition temperature: (Ce0.72Cu0.28)90−x Al10Fex (x = 0, 5 or 10) and Zn38Mg12Ca32Yb18

Compared with conventional bulk metallic glasses, Ce-based and Zn-based bulk metallic glasses have received considerable attention because of their possible application as structural and functional materials. Kinetic fragility parameter m in amorphous material presents degree of deviations from the Arrhenius law above the glass transition temperature (T_g) of the material. Kinetic fragility parameter (m) and Kauzmann temperature (T_K) in (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10) and Zn₃₈Mg₁₂Ca₃₂Yb₁₈ bulk metallic glasses have been determined by differential scanning calorimetry (DSC). Results show that Zn₃₈Mg₁₂Ca₃₂Yb₁₈ presents a higher m than (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10). The activation energies E_g for glass transition are 1.51 eV (x = 0), 1.59 eV (x = 5) and 1.83 eV (x = 10) in (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10), and 3.59 eV in Zn₃₈Mg₁₂Ca₃₂Yb₁₈, respectively. The values of E_g increase with increasing the Fe content in (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10) bulk metallic glasses. Kinetic fragility parameter m of bulk metallic glasses increases with the glass transition temperature T_g of bulk metallic glasses, in agreement with previous investigations.     

Experimental study and modelling of the thermoelastic behaviour of composite fuel in reactors - emphasis on spinel based composites.

Among the different ways studied to transmute minor actinides (MA), the heterogeneous mode is preferred, where high contents of MAs are put in selected reactor locations. An inert matrix fuel (IMF) with MA compound particles is commonly considered. Its specificities are such that its behaviour under irradiation cannot be predicted directly by standard fuel codes. In the reactor, the IMF thermomechanical behaviour may be calculated following several principles, taking into account all the microstructures considered. Thermal modelling has been tested by an experimental irradiation, called THERMHET (THERMal behaviour of HETerogeneous fuel), where three different IMF were studied.     

Effects of photoperiod and pair-feeding on lactation of cows fed corn or barley grain in total mixed rations

Effects of photoperiod and type of grain were assessed using 47 cows (wk 1; 59.5 d of lactation) exposed daily to 16 h of light (long day) and fed randomly one of two diets containing an equal amount of cracked corn or rolled barley. During wk 5, cows were assigned within each diet to long day and ad libitum feeding, short day (8 h of light: 2 h of dark: 2 h of light: 12 h of dark) and ad libitum feeding, or long day and ad libitum feeding (wk 5 to 8) followed by pair feeding with short day cows between wk 9 and 16. Milk composition was not affected by treatments. Between wk 9 and 16, long day cows fed for ad libitum consumption or pair fed produced 5 to 11% more milk than cows exposed to short day; feed intake of long day cows fed for ad libitum consumption was greater than short short day and long day cows pair fed cows. Milk yield and total feed intake were not affected by type of grain in the diet. In conclusion, long day photoperiod increased milk yield and feed intake.     

Novel TTLL5 Variants Associated with Cone-Rod Dystrophy and Early-Onset Severe Retinal Dystrophy

Variants of the TTLL5 gene, which encodes tubulin tyrosine ligase-like family member five, are a rare cause of cone dystrophy (COD) or cone-rod dystrophy (CORD). To date, only a few TTLL5 patients have been clinically and genetically described. In this study, we report five patients harbouring biallelic variants of TTLL5. Four adult patients presented either COD or CORD with onset in the late teenage years. The youngest patient had a phenotype of early onset severe retinal dystrophy (EOSRD). Genetic analysis was performed by targeted next generation sequencing of gene panels and assessment of copy number variants (CNV). We identified eight variants, of which six were novel, including two large multiexon deletions in patients with COD or CORD, while the EOSRD patient harboured the novel homozygous p.(Trp640*) variant and three distinct USH2A variants, which might explain the observed rod involvement. Our study highlights the role of TTLL5 in COD/CORD and the importance of large deletions. These findings suggest that COD or CORD patients lacking variants in known genes may harbour CNVs to be discovered in TTLL5, previously undetected by classical sequencing methods. In addition, variable phenotypes in TTLL5-associated patients might be due to the presence of additional gene defects.     

Supplementation of the diet with the functional fiber PolyGlycoplex? is well tolerated by healthy subjects in a clinical trial

Background  

The relationship of dietary fiber to overall health is of great importance, as beneficial effects have been demonstrated with the use of fiber from diverse sources, some traditional, other novel. PolyGlycopleX^? (PGX^?) is a unique proprietary product composed of three water-soluble polysaccharides, that when processed using novel technology give rise to a final product – a soluble, highly viscous functional fiber.     

Special issue on self-determination theory: A Canadian contribution.

A number of theories have been proposed to account for the role of motivation in human functioning. Amongst these theories, self-determination theory (e.g., Deci & Ryan, 1985) has been especially influential. Canadian researchers have played a key role in the development of this important theory. The collection of articles in this special issue concern self-determination theory. Following an introductory article by Deci and Ryan, a total of nine articles appear. These articles review research in a variety of contexts on various important themes, such as work, education, relationships, parenting, health, environmental issues, and psychotherapy. Finally, a concluding article provides some reflection on these articles and proposes directions for future research. As such, this special issue celebrates the role that Canadian researchers have played, and continue to play, in testing and refining this major motivation theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)