Rudolf Carnap : Construction et réduction. Textes inédits sur le physicalisme 1922-1955

Les textes inédits traduits et présentés dans ce volume constituent un témoignage exceptionnel quant à l'évolution de la pensée de Carnap, l'un des fondateurs de la philosophie analytique. Des premières ébauches d'une construction logique du monde à l'analyse logique des propositions du langage, ils nous font en effet assister aux différents moments d'un programme philosophique inscrit dans le débat du physicalisme et de l'unité de la science. La réductibilité des termes de la psychologie puis de la biologie aux termes de la physique implique-t-elle la dérivabilité de leurs lois aux siennes ? Y a-t-il bonne conséquence d'une épistémologie de la réduction à une réduction ontologique ? Le monde, en somme, est-il entièrement explicable par le langage, et si oui, lequel ?

Respiratory effects of an exposure to wheat dust among grain workers and farmers: a longitudinal study

OBJECTIVES: Agriculture is considered one of the occupations most at risk of acute or chronic respiratory problems. The aim of our study was to determine from which level of exposure to organic dust the respiratory function is chronically affected in workers involved in wheat grain or straw manipulation and to test if some of these working populations can recover their respiratory function after an exposure decrease. METHOD: 87 workers exposed to wheat dust: farmers, harvesters, silo workers and livestock farmers and 62 non exposed workers, were included into a longitudinal study comprising two visits at a six months interval with lung function measurements and symptom questionnaires. Cumulative and mean exposure to wheat dust were generated from detailed work history of each worker and a task-exposure matrix based on task-specific exposure measurements. Immunoglobulins (IgG and IgE) specific of the most frequent microorganisms in wheat dust have been determined. RESULTS: FEV1 decreased significantly with the cumulative exposure and mean exposure levels. The estimated decrease was close to 200 mL per year of high exposure, which corresponds roughly to levels of wheat dust higher than 10 mg/m(3). Peak expiratory flow and several acute symptoms correlate with recent exposure level. Recovery of the respiratory function six months after exposure to wheat dust and evolution of exposure indicators in workers blood (IgG and IgE) will be discussed. CONCLUSIONS: These results show a chronic effect of exposure to wheat dust on bronchial obstruction. Short term effects and reversibility will be assessed using the full study results.

The effect of workplace smoking bans on heart rate variability and pulse wave velocity of non-smoking hospitality workers

OBJECTIVES: To investigate the effect of a change in second-hand smoke (SHS) exposure on heart rate variability (HRV) and pulse wave velocity (PWV), this study utilized a quasi-experimental setting when a smoking ban was introduced. METHODS: HRV, a quantitative marker of autonomic activity of the nervous system, and PWV, a marker of arterial stiffness, were measured in 55 non-smoking hospitality workers before and 3-12 months after a smoking ban and compared to a control group that did not experience an exposure change. SHS exposure was determined with a nicotine-specific badge and expressed as inhaled cigarette equivalents per day (CE/d). RESULTS: PWV and HRV parameters significantly changed in a dose-dependent manner in the intervention group as compared to the control group. A one CE/d decrease was associated with a 2.3 % (95 % CI 0.2-4.4; p = 0.031) higher root mean square of successive differences (RMSSD), a 5.7 % (95 % CI 0.9-10.2; p = 0.02) higher high-frequency component and a 0.72 % (95 % CI 0.40-1.05; p < 0.001) lower PWV. CONCLUSIONS: PWV and HRV significantly improved after introducing smoke-free workplaces indicating a decreased cardiovascular risk.

Symptoms of chronic stress at work in NGO workers

Working in a NGO often involves providing life saving resources (food, medicine, equipment, water, etc) to needy populations around the globe. Such duty requires highly dedicated employees and humanitarian workers are said to face a hign degree of pressure in their daily work. Despite the evidence of taxing work demands, and a high potential for stress related problems, very few studies on occupational chronic stress have specifically looked at NGO workers. Assuming that "field stress" can relay to workers at headquarters, we carried out an exploratory study about occupational health among employees of a NGO's headquarters. We sent a questionnaire to all employees (N=130) of a NGO headquarters located in Switzerland. We used the TST questionnaire (French version of the Langner's questionnaire on psychiatric symptoms) to identify cases with potential mental health problems. We also included in the questionnaire some items about motivation, acknowledgment, work-life balance, job demand, and autonomy. A total of 75 employees answered our questionnaire (57% response rate). 44% of our sample were men (n=33) and 56% were women (n=42). The mean age was of 40 years (SD=7.6). 56% were working at the headquarters of the NGO in questions as of 2 years or less. Not surprisingly, a majority of respondents reported to be highly motivated (74%) and the meaning of work was important for 80% of them. However, 35% indicated having problems in conciliating their private and professional life. Most frequent reported symptoms included feeling "weak all over" (81%), having "trouble getting asleep often" (35%), "clogging in nose" (35%), feeling "nervous often" (33%), and "memory not all right" (33%). The score for psychiatric symptoms was high in 8 (11%) employees whose health might therefore be at risk. In comparison, other sudies showed that this proportion was 9% for French teachers and 16% for sales personnel1. Results show that symptoms of mental health problems do occur among NGO workers. Some of these symptoms are known to be linked to occupational stress. Chronic stress manifests itself first in non-specific symptoms (e.g. fatigue) and later in specific pathologies. This could explain the relatively low proportion of cases with a high score in Langner's scale than was expected. Therefore, we hypothesize a healthy worker effect. The fact that our sample is 40 years old in average, and that the turnover is quite high can also support this hypothesis. Further research is needed in order to better understand occupational stress in this specific population. An upcoming study will investigate the role of organizational factors associated with health complaints. Therefore, a longitudinal survey including quantitative and qualitative methods is appropriate.

Workers exposed to wood dust have an increased micronucleus frequency in nasal and buccal cells: results from a pilot study

Wood dust is recognised as a human carcinogen, based on the strong association of wood dust exposure and the elevated risk of malignant tumours of the nasal cavity and paranasal sinuses [sino-nasal cancer (SNC)]. The study aimed to assess genetic damage in workers exposed to wood dust using biomarkers in both buccal and nasal cells that reflect genome instability events, cellular proliferation and cell death frequencies. Nasal and buccal epithelial cells were collected from 31 parquet layers, installers, carpenters and furniture workers (exposed group) and 19 non-exposed workers located in Switzerland. Micronucleus (MN) frequencies were scored in nasal and buccal cells collected among woodworkers. Other nuclear anomalies in buccal cells were measured through the use of the buccal micronucleus cytome assay. MN frequencies in nasal and buccal cells were significantly higher in the exposed group compared to the non-exposed group; odds ratio for nasal cells 3.1 [95% confidence interval (CI) 1.8-5.1] and buccal cells 1.8 (95% CI 1.3-2.4). The exposed group had higher frequencies of cells with nuclear buds, karyorrhectic, pyknotic, karyolytic cells and a decrease in the frequency of basal, binucleated and condensed cells compared to the non-exposed group. Our study confirms that woodworkers have an elevated risk for chromosomal instability in cells of the aerodigestive tract. The MN assay in nasal cells may become a relevant biomonitoring tool in the future for early detection of SNC risk. Future studies should seek to standardise the protocol for MN frequency in nasal cells similar to that for MN in buccal cells.

Life designing: A paradigm for career construction in the 21st century

At the beginning of the 21st century, a new social arrangement of work poses a series of questions and challenges to scholars who aim to help people develop their working lives. Given the globalization of career counseling, we decided to address these issues and then to formulate potentially innovative responses in an international forum. We used this approach to avoid the difficulties of creating models and methods in one country and then trying to export them to other countries where they would be adapted for use. This article presents the initial outcome of this collaboration, a counseling model and methods. The life-designing model for career intervention endorses five presuppositions about people and their work lives: contextual possibilities, dynamic processes, non-linear progression, multiple perspectives, and personal patterns. Thinking from these five presuppositions, we have crafted a contextualized model based on the epistemology of social constructionism, particularly recognizing that an individual's knowledge and identity are the product of social interaction and that meaning is co-constructed through discourse. The life-design framework for counseling implements the theories of self-constructing [Guichard, J. (2005). Life-long self-construction. International Journal for Educational and Vocational Guidance, 5, 111-124] and career construction [Savickas, M. L. (2005). The theory and practice of career construction. In S. D. Brown & R. W. Lent (Eds.), Career development and counselling: putting theory and research to work (pp. 42-70). Hoboken, NJ: Wiley] that describe vocational behavior and its development. Thus, the framework is structured to be life-long, holistic, contextual, and preventive.

A course on collaboration between social workers and general practitioners during their vocational training

The educational programme reported was an experiment in the vocational training scheme of the department of General Practice, Erasmus University, Rotterdam, Holland, and is now part of the course. The programme focused on the training in team function (co-operation) given to trainee GPs and social workers. It became clear that both groups during their professional training develop markedly different attitudes and views about patient (client) care. These differences form a fundamental handicap in any discussion about teamwork. During the programme the students were made aware of this divergence of viewpoint and were taught how to handle these resulting handicaps and, if possible, to eliminate them.

Construction mechanisms and thermal evolution of upper crustal intrusions : the Saint-Jean-du-Doigt bimodal intrusion (Brittany, France)

Understanding the emplacement and growth of intrusive bodies in terms of mechanism, duration, ther¬mal evolution and rates are fundamental aspects of crustal evolution. Recent studies show that many plutons grow in several Ma by in situ accretion of discrete magma pulses, which constitute small-scale magmatic reservoirs. The residence time of magmas, and hence their capacities to interact and differentiate, are con¬trolled by the local thermal environment. The latter is highly dependant on 1) the emplacement depth, 2) the magmas and country rock composition, 3) the country rock thermal conductivity, 4) the rate of magma injection and 5) the geometry of the intrusion. In shallow level plutons, where magmas solidify quickly, evi¬dence for magma mixing and/or differentiation processes is considered by many authors to be inherited from deeper levels. This work shows however that in-situ differentiation and magma interactions occurred within basaltic and felsic sills at shallow depth (0.3 GPa) in the St-Jean-du-Doigt (SJDD) bimodal intrusion, France. This intrusion emplaced ca. 347 Ma ago (IDTIMS U/Pb on zircon) in the Precambrian crust of the Armori- can massif and preserves remarkable sill-like emplacement processes of bimodal mafic-felsic magmas. Field evidence coupled to high precision zircon U-Pb dating document progressive thermal maturation within the incrementally built ioppolith. Early m-thick mafic sills (eastern part) form the roof of the intrusion and are homogeneous and fine-grained with planar contacts with neighboring felsic sills; within a minimal 0.8 Ma time span, the system gets warmer (western part). Sills are emplaced by under-accretion under the old east¬ern part, interact and mingle. A striking feature of this younger, warmer part is in-situ differentiation of the mafic sills in the top 40 cm of the layer, which suggests liquids survival in the shallow crust. Rheological and thermal models were performed in order to determine the parameters required to allow this observed in- situ differentiation-accumulation processes. Strong constraints such as total emplacement durations (ca. 0.8 Ma, TIMS date) and pluton thickness (1.5 Km, gravity model) allow a quantitative estimation of the various parameters required (injection rates, incubation time,...). The results show that in-situ differentiation may be achieved in less than 10 years at such shallow depth, provided that: (1) The differentiating sills are injected beneath consolidated, yet still warm basalt sills, which act as low conductive insulating screens (eastern part formation in the SJDD intrusion). The latter are emplaced in a very short time (800 years) at high injection rate (0.5 m/y) in order to create a "hot zone" in the shallow crust (incubation time). This implies that nearly 1/3 of the pluton (400m) is emplaced by a subsequent and sustained magmatic activity occurring on a short time scale at the very beginning of the system. (2) Once incubation time is achieved, the calculations show that a small hot zone is created at the base of the sill pile, where new injections stay above their solidus T°C and may interact and differentiate. Extraction of differentiated residual liquids might eventually take place and mix with newly injected magma as documented in active syn-emplacement shear-zones within the "warm" part of the pluton. (3) Finally, the model show that in order to maintain a permanent hot zone at shallow level, injection rate must be of 0.03 m/y with injection of 5m thick basaltic sills eveiy 130yr, imply¬ing formation of a 15 km thick pluton. As this thickness is in contradiction with the one calculated for SJDD (1.5 Km) and exceed much the average thickness observed for many shallow level plutons, I infer that there is no permanent hot zone (or magma chambers) at such shallow level. I rather propose formation of small, ephemeral (10-15yr) reservoirs, which represent only small portions of the final size of the pluton. Thermal calculations show that, in the case of SJDD, 5m thick basaltic sills emplaced every 1500 y, allow formation of such ephemeral reservoirs. The latter are formed by several sills, which are in a mushy state and may interact and differentiate during a short time.The mineralogical, chemical and isotopic data presented in this study suggest a signature intermediate be¬tween E-MORB- and arc-like for the SJDD mafic sills and feeder dykes. The mantle source involved produced hydrated magmas and may be astenosphere modified by "arc-type" components, probably related to a sub¬ducting slab. Combined fluid mobile/immobile trace elements and Sr-Nd isotopes suggest that such subduc¬tion components are mainly fluids derived from altered oceanic crust with minor effect from the subducted sediments. Close match between the SJDD compositions and BABB may point to a continental back-arc setting with little crustal contamination. If so, the SjDD intrusion is a major witness of an extensional tectonic regime during the Early-Carboniferous, linked to the subduction of the Rheno-Hercynian Ocean beneath the Variscan terranes. Also of interest is the unusual association of cogenetic (same isotopic compositions) K-feldspar A- type granite and albite-granite. A-type granites may form by magma mixing between the mafic magma and crustal melts. Alternatively, they might derive from the melting of a biotite-bearing quartz-feldspathic crustal protolith triggered by early mafic injections at low crustal levels. Albite-granite may form by plagioclase cu¬mulate remelting issued from A-type magma differentiation.