De l’idéologie de l’espace à l’idéologie dans l’espace

Plutôt que d'étudier les dimensions idéologiques du discours des géographes, cet article s'interroge sur la pertinence et les méthodes possibles d'une lecture de l'inscription de la dimension idéologique d'une société dans l'espace que celle-ci a produit. Rappelant l'importance d'une réflexion géographique sur les caractéristiques spatiales liées à l'idéologie d'une formation sociale, les auteurs s'appuient sur les études ayant pour but de mesurer la qualité de la vie, telle que perçue par les habitants, ainsi que sur celles portant sur la perception et l'économie politique du risque nucléaire pour reconnaître l'intérêt et la possibilité, sous certaines conditions, d'une étude scientifique des faits idéologiques, tels qu'en dernière analyse ils se lisent dans l'espace géographique lui-même.Rather than studying the ideological dimension of geographical discourse, this article addresses the question of the relevance and possible methodology for analyzing ideological dimensions, within the space created by a given society. Recalling the importance of a geographical approach to spatial characteristics linked to the ideologies of social formations, the authors base their work on studies whose aim is to measure the quality of life, as perceived by the population, as well as those dealing with the awareness and political economy of nuclear risks, to define the relevance and feasibility, under certain circumstances, of the scientific study of ideological phenomena, such as can be ascertained, in the final analysis, from a given geographical space

Catastrophic vs Gradual Collapse of Thin-Walled Nanocrystalline Ni Hollow Cylinders As Building Blocks of Microlattice Structures

Lightweight yet stiff and strong lattice structures are attractive for various engineering applications, such as cores of sandwich shells and components designed for impact mitigation. Recent breakthroughs in manufacturing enable efficient fabrication of hierarchically architected microlattices, with dimensional control spanning seven orders of magnitude in length scale. These materials have the potential to exploit desirable nanoscale-size effects in a macroscopic structure, as long as their mechanical behavior at each appropriate scale – nano, micro, and macro levels – is properly understood. In this letter, we report the nanomechanical response of individual microlattice members. We show that hollow nanocrystalline Ni cylinders differing only in wall thicknesses, 500 and 150 nm, exhibit strikingly different collapse modes: the 500 nm sample collapses in a brittle manner, via a single strain burst, while the 150 nm sample shows a gradual collapse, via a series of small and discrete strain bursts. Further, compressive strength in 150 nm sample is 99.2% lower than predicted by shell buckling theory, likely due to localized buckling and fracture events observed during in situ compression experiments. We attribute this difference to the size-induced transition in deformation behavior, unique to nanoscale, and discuss it in the framework of “size effects” in crystalline strength

In situ Mechanical Testing Reveals Periodic Buckle Nucleation and Propagation in Carbon Nanotube Bundles

Uniaxial compression studies are performed on 50-µm-diameter bundles of nominally vertical, intertwined carbon nanotubes grown via chemical vapor deposition from a photolithographically defined catalyst. The inhomogeneous microstructure is examined, demonstrating density and tube orientation gradients, believed to play a role in the unique periodic buckling deformation mechanism. Through in situ uniaxial compression experiments it is discovered that the characteristic bottom-to-top sequential buckling proceeds by first nucleating on the bundle surface and subsequently propagating laterally through the bundle, gradually collapsing the entire structure. The effects of strain rate are explored, and storage and loss stiffnesses are analyzed in the context of energy dissipation

Physical Activity and Cognitive-Health Content in Top-Circulating Magazines, 2006–2008

Physical activity may promote cognitive health in older adults. Popular media play an important role in preventive health communication. This study examined articles discussing associations between physical activity and cognitive health in top-circulating magazines targeting older adults. 42,753 pages of magazines published from 2006 to 2008 were reviewed; 26 articles met inclusion criteria. Explanations regarding the link between physical activity and cognitive health were provided in 57.7% of articles. These explanations were generally consistent with empirical evidence; however, few articles included empirical evidence. Physical activity recommendations were presented in 80.8% of articles; a wide range was recommended (90–300 min of physical activity per wk). Socioeconomic status and education level were not mentioned in the text. Results suggest an opportunity for greater coverage regarding the role of physical activity in promoting cognitive health in popular media. Magazine content would benefit from including more empirical evidence, culturally sensitive content, and physical activity recommendations that are consistent with U.S. guidelines

Ultra-fast calorimetry study of Ge₂Sb₂Te₅ crystallization between dielectric layers

Phase changes in chalcogenides such as Ge2Sb2Te5 can be exploited in non-volatile random-access memory, with fast crystallization crucial for device operation. Ultra-fast differential scanning calorimetry, heating at rates up to 40,000K s-1, has been used to study the crystallization of amorphous Ge2Sb2Te5 with and without sandwich layers of ZnS-SiO2. At heating rates up to 1000K s-1, the sandwich layers retard crystallization, an effect attributed to crystallization-induced stress. At greater heating rates (>or = 5000K s-1), and consequently higher crystallization temperatures, the stress is relaxed, and sandwich layers catalyze crystallization. Implications for memory-device performance are discussed

Acute Ingestion of Dark Chocolate Fails to Affect Running Economy in Recreational Female Runners

Topics in Exercise Science and Kinesiology Volume 5: Issue 1, Article 1, 2024. Ingestion of dark chocolate (DC), a dietary source high in flavanols, may increase nitric oxide bioavailability. Elevating blood nitric oxide concentrations may augment metabolic efficiency by reducing the amount of oxygen or energy needed to perform a given task. Utilizing a crossover design, the purpose of this study was to investigate the effect of acute ingestion of DC on running economy (RE). Nineteen recreationally trained females (age: 20±1 years) volunteered for this investigation, with 16 completing all procedures (n = 16). Two-hours before RE assessment, participants consumed either 42.5 g of DC or an isocaloric amount of white chocolate (WC) (37.2 g) with a 34 mg caffeine pill. Participants ran on the treadmill at 2.68 m/s for 10-minutes to assess RE. However, only the last 5-minutes of the test were used for oxygen utilization (VO2), energy expenditure (EE), and respiratory exchange ratio (RER) determination via indirect calorimetry. Identical testing procedures were utilized for DC and WC treatments with a seven-day washout period separating trials. A repeated measure paired t-test was used to determine differences between dependent variables with statistical significance set at p \u3c 0.05. There were no significant mean differences (ps \u3e 0.05) between trials for VO2, EE, or RER. In conclusion, supplementation of DC 2-hours prior to steady state running had no effect on RE or fuel utilization compared to an isocaloric serving of WC in recreational female runners

Multi-scenario modelling of learning

International audienceDesigning an educational scenario is a sensitive and challenging activity because it is the vector of learning. However, the designed scenario may not correspond to some learners’ characteristics (pace of work, cognitive styles, emotional factors, prerequisite knowledge, …). To personalize the learning task and adapt it gradually to each learner, several scenarios are needed. Adaptation and personalization are difficult because it is necessary on the one hand to know in advance the profiles and on the other hand to produce the multiple scenarios corresponding to these profiles. Our model allows to design many scenarios without knowing the learner profiles beforehand. Furthermore, it offers each learner opportunities to choose a scenario and to change it during their learning process. The model ensures that all announced objectives have enough resources for acquiring knowledge and activities for evaluation

Identification And Characterization Of A Second Encephalitogenic Determinant Of Myelin Proteolipid Protein (Residues 178-191) For SJL Mice

We previously described a synthetic peptide of myelin proteolipid protein (PLP), peptide 139-151, which induces experimental allergic encephalomyelitis in SJL/J (H-2s) mice. We have now identified an additional determinant, PLP residues 178-191, that is also a potent encephalitogen in this strain. When PLP peptide 178-191 was compared with peptide 139-151 on an equimolar basis, the day of onset of disease induced by PLP 178-191 was earlier, but the incidence, severity, and histologic features were indistinguishable. Lymph node cells from animals immunized with the whole PLP molecule responded to both PLP 178-191 and 139-151, suggesting immunologic codominance of the two epitopes. PLP 178-191 elicited stronger proliferative responses and this may relate to the earlier onset of disease induced with this peptide. Two CD4+, peptide-specific, I-A(s)-restricted T cell lines, selected by stimulation of lymph node cells with either PLP 178-191 or 139-151, were each encephalitogenic in naive syngeneic mice. The presence of multiple encephalitogenic codominant PLP epitopes within a single mouse strain emphasizes the complexity of the immune response to PLP and its potential as a target Ag in autoimmune demyelinating diseases

The changing UK careers landscape : tidal waves, turbulence and transformation

This article explores how the UK careers landscape in each of the four home nations is changing in response to neo-liberal policies. In this context, careers services are increasingly under pressure to demonstrate their added value, impact and returns on investment. As fiscal arrangements tighten and governments state their preferences and priorities for national careers services, differing strategic responses are beginning to emerge. A quasi-market, experimental approach is now the dominant discourse in England, in contrast to differing and complementary arrangements in Northern Ireland, Scotland and Wales. The article suggests that insofar as these developments are transforming national careers services, they are also creating significant challenges which require new forms of policy imagery and imagination for high-impact, all-age careers services

Mineral sinks within ripening grape berries (Vitis vinifera L.)

Trends in the accumulation of mineral elements into the grape berry components give information about vascular flow into the berry. Shiraz berries were dissected into receptacle, skin, pulp, brush and seeds and the accumulation of 10 mineral elements into these components was followed through development. The elements were separated into two categories according to their accumulation pattern into the berry. The first group of elements continued to accumulate throughout berry growth and ripening, and was comprised of  phloem-mobile potassium, phosphorus, sulphur, magnesium, boron, iron and copper. The second group of elements accumulated mostly prior to veraison, and included the xylem-mobile minerals calcium, manganese and zinc. These results indicate that the xylem contribution to berry growth diminished after veraison. Berry fresh weight, dry weight, as well as berry sugar content, were all highly correlated with berry potassium content. While the pulp and skin were the strongest sinks for potassium and boron, seeds were the strongest sinks for calcium, phosphorus, sulphur, manganese and zinc. With the exception of calcium and manganese, seeds ceased to accumulate most elements during late ripening. The berry receptacle and brush did not accumulate any of the elements to levels above those of the other berry components at any stage of development. Therefore, they did not act as sinks for xylem- or phloem-mobile elements as vascular flow to the pulp and skin slowed.