On spectral scaling laws for incompressible anisotropic MHD turbulence

A heuristic model is given for anisotropic magnetohydrodynamics (MHD) turbulence in the presence of a uniform external magnetic field B_0 {\bf {\hat e}_{\pa}}. The model is valid for both moderate and strong $B_0$ and is able to describe both the strong and weak wave turbulence regimes as well as the transition between them. The main ingredient of the model is the assumption of constant ratio at all scales between \add{the} linear wave period and \add{the} nonlinear turnover timescale. Contrary to the model of critical balance introduced by Goldreich and Sridhar [P. Goldreich and S. Sridhar, ApJ {\bf 438}, 763 (1995)], it is not assumed in addition that this ratio be equal to unity at all scales which allows us to use the Iroshnikov-Kraichnan phenomenology. It is then possible to recover the widely observed anisotropic scaling law \kpa \propto \kpe^{2/3} between parallel and perpendicular wavenumbers (with reference to B_0 {\bf {\hat e}_{\pa}}) and to obtain the universal prediction, $3\alpha + 2\beta = 7$, for the total energy spectrum E(\kpe,\kpa) \sim \kpe^{-\alpha} \kpa^{-\beta}. In particular, with such a prediction the weak Alfv\'en wave turbulence constant-flux solution is recovered and, for the first time, a possible explanation to its precursor found numerically by Galtier et al [S. Galtier et al., J. Plasma Phys. {\bf 63}, 447 (2000)] is given

Évaluation des retombées d'un programme de formation en gestion de dirigeants de PME

Cet article rend compte d'une expérience d'évaluation d'un programme de formation offert à l'intention de propriétairesdirigeants de PME québécoises par le ministère de l'Industrie, du Commerce et de la Technologie de la province. La recherche utilise le modèle de Kirkpatrick qui propose d'évaluer un programme déformation selon quatre niveaux distincts: réactions, apprentissage, comportements et résultats. Deux cent quatre-vingt-un participants ont été rejoints par téléphone au moins un an après la tenue de leur séminaire. L'étude documente d'une façon descriptive les différents niveaux d'impact du programme de formation. Elle apporte un éclairage nouveau sur une opération rarement effectuée qui présente de nombreuses difficultés d'ordre théorique et opérationnel.Leaders of Quebec small businesses have access to a large number of management training programs offered by private and public agencies. Those who enroll in such programs hope to generate positive results for their business. However, the real impacts of the programs are not well documented. This paper is an account of an empirical evaluation of a training program offered to owner-managers of small businesses by the ministere de l'Industrie, du Commerce et de la Technologie (MICT) of the Province of Quebec. CONTEXT OF THE STUDYIn 1988, the MICT offered 28 different seminars, 18 of which were aimed at owners of industrial firms, and 10 at owners of commercial and service companies. The topics discussed covered a wide range of subjects presented in workshops going from basic seminars (such as, financial and human resources management) to advanced seminars (such as, "just-in-time" management techniques and strategic planning). Seminars are in the form of one-day workshops with 10 to 15 participants.A workshop leader, generally a consultant, university professor or businessman recognized for his competence, is responsible for the transmission of information using audio-visual materials. He introduces many practical examples and encourages communication between the participants, who are then invited to discuss their real-life business problems and to prepare concrete action plans to be implemented when they return to their organization.THE KIRKPATRICK MODELA review of the literature in training program evaluation indicates that this operation is rated as essential by all authors in the field. However, it is only rarely carried out in practice. Even when an evaluation is attempted, it is often limited to measuring the participants' reaction to the seminar since it presents a number of theoretical and operational difficulties. However, our review of the literature enabled us to locate a model which is accepted as an authority by training professionals. The Kirkpatrick model proposes an analysis of the effectiveness of a training program according to four levels: reactions, learning and behaviours of the participant and results for the organization.METHODOLOGYFrom September 1986 to June 1987, the MICT seminars attracted some 3000 people. The sample is made up of about 10% of the population, namely 189 leaders of industnal businesses and 92 leaders of commercial businesses, making a total of 281 in all. Data was gathered by phone in March 1988, approximately one year after the seminar was held, using a questionnaire based on the Kirkpatrick model.RESULTSThe participants' reactions towards the seminar are the first evaluation level in the Kirkpatrick model. On the whole, the MICT seminars seem to have been well rated by the participants. The satisfaction level is very high with respect to content and format as well as teaching and logistic support for the sessions. The second evaluation level, learning, is an attempt to determine to what extent the information transmitted in the seminars was learned and mastered. The seminars seem to have been well assimilated by the participants, since 86,9% of them state that they are completely or moderately in a position to use what they have learned during the session.The third evaluation level aims to shed light on the changes undergone by the participant, new behaviours and projects undertaken as a result of the new knowledge. Changes in the participant himself as a result of the seminar were identified. Two hundred and thirty-eight participants generated 306 reflections that were classified under three headings: (1) Awakening, Increase in Knowledge and Awareness (33,7%), (2) Changes in Values and/or Priorities (33,3%), (3) Changes in Behaviour (33%).The seminars had a concrete impact in terms of new projects. In fact, 51,2% of the respondents state that the knowledge acquired gave rise to a concrete project or activity in their enterprise. They mentioned 198 activities or projects which have been classified into nine categories. They are: (1) New Systems or Methods (38,9%), (2) Changes to Already Existing Systems or Methods (27,3%), (3) Analysis and Planning Activities (8,6%), (4) Establishment and Start-up of a New Unit (8,6%), (5) Training Activities (6,1%), (6) Hiring of Personnel (3,5%), (7) Purchase of Equipment or Real Estate (1,5%). Three per cent of the respondents were unable to specify the exact nature of their project.The fourth evaluation level of the Kirkpatrick model uses different performance indicators to measure the effects of new projects and behaviour patterns on the organization. One hundred and fourty-four respondents listed 205 consequences for their own enterprise. These consequences were classified according to the type of impact.They are positive for the enterprise in all but a few cases (4). Negative impacts are considered as temporary or compensated by positive ones in other functional spheres of the enterprise. The consequences for the enterprise are: (1) Turnover/ Sales (13,7%), (2) Profits (9,8%), (3) Costs (12,7%), (4) Management/Control (20,5%), (5) Personnel (18,5%), (6) Product (7,3%), (7) Market (6,3%), (8) Undefïned or Non-measurable Impact (9,3%), (8) Negative Impact (2,0%). CONCLUSIONBased on the results of the study as a whole, it is possible to summarize the impacts of the seminars on the participants and their businesses as being positive or even very positive. The program of the management seminars offered by the MICT seems to be a valuable tool for spreading information among small business managers whose need for training has been confirmed by several studies. The Kirkpatrick model was found to be a valuable tool in this evaluation. It is systematic, complete and intuitively logical. Moreover, it was relatively easy to operationalize. The instrument developed for this study is economic and flexible, since the survey may be done by phone. To conclude, the Kirkpatrick model is an adequate response to the theoretical, methodological and practical challenges of training program evaluation

Time-dependent behaviour of hardened cement paste under isotropic loading

International audienceThe experimental results of isotropic compression tests performed at 20°C and 90°C on a class G hardened cement paste hydrated at 90°C (Ghabezloo et al., 2008, Cem. Conc. Res. 38, 1424-1437) have been revisited considering time-dependent response. Within the frame of a viscoplastic model, the non-linear responses of the volumetric strains as observed in drained and undrained tests and of the pore pressure in undrained tests are analysed. The calibration of model parameters based on experimental data allows to study the effect of the test temperature on the viscous response of hardened cement paste showing that the creep is more pronounced for a higher test temperature. The effect of the hydration temperature on the time dependent behaviour is also studied by evaluating the model parameters for a cement paste hydrated at 60°C. The time-dependent deformations are more pronounced for hydration at a higher temperature

Clinico-pathological considerations in a 48-years-old female with acute kidney injury: is it lupus nephritis, ANCA-associated vasculitis or something else?

BACKGROUND: The value of ANCA positivity in the setting of systemic lupus erythematous and their pathogenicity remains uncertain. CASE PRESENTATION: We report the case of a 48-year-old female with rapidly progressive kidney failure, arthro-myalgia and weight loss. Auto-immune screening showed anti-dsDNA antibodies, complement consumption and triple ANCA positivity. A first kidney biopsy done at presentation highlighted class IV-G glomerulonephritis with elective extra-capillary involvement and mainly C1q glomerular deposition at immunofluorescence study. After three months of a regimen combining steroids and cyclophosphamide, a second biopsy was performed and showed class IV-G glomerulonephritis with mainly endocapillary proliferation. CONCLUSION: This case is atypical in view of immunological profile and kidney histopathological presentation and evolution and gives rise to discussion in view of recent data on ANCA value in lupus nephritis, and suggests that different auto-immune pathways may be involved in lupus nephritis

Comparative study of the Martian suprathermal electron depletions based on Mars Global Surveyor, Mars Express and Mars Atmosphere and Volatile EvolutioN missions observations

Nightside suprathermal electron depletions have been observed at Mars by three spacecraft to date: Mars Global Surveyor, Mars Express, and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. This spatial and temporal diversity of measurements allows us to propose here a comprehensive view of the Martian electron depletions through the first multispacecraft study of the phenomenon. We have analyzed data recorded by the three spacecraft from 1999 to 2015 in order to better understand the distribution of the electron depletions and their creation mechanisms. Three simple criteria adapted to each mission have been implemented to identify more than 134,500 electron depletions observed between 125 and 900 km altitude. The geographical distribution maps of the electron depletions detected by the three spacecraft confirm the strong link existing between electron depletions and crustal magnetic field at altitudes greater than ~170 km. At these altitudes, the distribution of electron depletions is strongly different in the two hemispheres, with a far greater chance to observe an electron depletion in the Southern Hemisphere, where the strongest crustal magnetic sources are located. However, the unique MAVEN observations reveal that below a transition region near 160–170 km altitude the distribution of electron depletions is the same in both hemispheres, with no particular dependence on crustal magnetic fields. This result supports the suggestion made by previous studies that these low-altitudes events are produced through electron absorption by atmospheric CO2

Late Quaternary episodes of clastic sediment deposition in the Tarimba Cave, Central Brazil

peer reviewedThe study presents three sedimentary profiles from Tarimba cave in central Brazil. The data allow constraining the late Quaternary sedimentary evolution of cave systems in the region. A multi-techniques approach was used to characterize sediment texture (grain size and circularity index), mineralogical composition (X-Ray Diffraction), chemical composition (ICP-OES) and deposition ages (Optically Stimulated Luminescence and radiocarbon). Eight sedimentary facies were identified, including a facies formed by autochthonous sediments (Guano) and seven facies formed by allochthonous siliciclastic sediments. The siliciclastic facies range from clayey to gravelly deposits that correspond to high-density gravity flows (Diamicton) and water laid traction process of varied deposition energy (Channel, Backswamp, and Slackwater). The studied deposits reflect an intense cave filing from the Middle to Late Pleistocene in the last 200 Ka. Subsequent depositional events formed three sedimentation phases: the first before 200 Ka corresponding to a larger granulometric interval, clay to gravel, identified through erosive surfaces; the second, after 197 Ka, is composed of sandy sediments and oscillations in the water flow energy. The third phase between 87 and 52 Ka (which covered the other stages) was responsible for the last fluvial deposition

Pre-transplant CD45RC expression on blood T cells differentiates patients with cancer and rejection after kidney transplantation

Background Biological biomarkers to stratify cancer risk before kidney transplantation are lacking. Several data support that tumor development and growth is associated with a tolerant immune profile. T cells expressing low levels of CD45RC preferentially secrete regulatory cytokines and contain regulatory T cell subset. In contrast, T cells expressing high levels of CD45RC have been shown to secrete proinflammatory cytokines, to drive alloreactivity and to predict acute rejection (AR) in kidney transplant patients. In the present work, we evaluated whether pre-transplant CD45RClow T cell subset was predictive of post-transplant cancer occurrence. Methods We performed an observational cohort study of 89 consecutive first time kidney transplant patients whose CD45RC T cell expression was determined by flow cytometry before transplantation. Post-transplant events including cancer, AR, and death were assessed retrospectively. Results After a mean follow-up of 11.1±4.1 years, cancer occurred in 25 patients (28.1%) and was associated with a decreased pre-transplant proportion of CD4+CD45RChigh T cells, with a frequency below 51.9% conferring a 3.7-fold increased risk of post-transplant malignancy (HR 3.71 [1.24–11.1], p = 0.019). The sensibility, specificity, negative predictive and positive predictive values of CD4+CD45RChigh<51.9% were 84.0, 54.7, 89.8 and 42.0% respectively. Confirming our previous results, frequency of CD8+CD45RChigh T cells above 52.1% was associated with AR, conferring a 20-fold increased risk (HR 21.7 [2.67–176.2], p = 0.0004). The sensibility, specificity, negative predictive and positive predictive values of CD8+CD45RChigh>52.1% were 94.5, 68.0, 34.7 and 98.6% respectively. Frequency of CD4+CD45RChigh T cells was positively correlated with those of CD8+CD45RChigh (p<0.0001), suggesting that recipients with high AR risk display a low cancer risk. Conclusion High frequency of CD45RChigh T cells was associated with AR, while low frequency was associated with cancer. Thus, CD45RC expression on T cells appears as a double-edged sword biomarker of promising interest to assess both cancer and AR risk before kidney transplantation

Altitude dependence of nightside Martian suprathermal electron depletions as revealed by MAVEN observations

The MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft is providing new detailed observations of the Martian ionosphere thanks to its unique orbital coverage and instrument suite. During most periapsis passages on the nightside ionosphere suprathermal electron depletions were detected. A simple criterion was implemented to identify the 1742 depletions observed from 16 November 2014 to 28 February 2015. A statistical analysis reveals that the main ion and electron populations within the depletions are surprisingly constant in time and altitude. Absorption by CO2 is the main loss process for suprathermal electrons, and electrons that strongly peaked around 6 eV are resulting from this interaction. The observation of depletions appears however highly dependent on altitude. Depletions are mainly located above strong crustal magnetic sources above 170 km, whereas the depletions observed for the first time below 170 km are globally scattered onto the Martian surface with no particular dependence on crustal fields

Cross-species amplification of 41 microsatellites in European cyprinids: A tool for evolutionary, population genetics and hybridization studies

<p>Abstract</p> <p>Background</p> <p>Cyprinids display the most abundant and widespread species among the European freshwater Teleostei and are known to hybridize quite commonly. Nevertheless, a limited number of markers for conducting comparative differentiation, evolutionary and hybridization dynamics studies are available to date.</p> <p>Findings</p> <p>Five multiplex PCR sets were optimized in order to assay 41 cyprinid-specific polymorphic microsatellite loci (including 10 novel loci isolated from <it>Chondrostoma nasus nasus, Chondrostoma toxostoma toxostoma </it>and <it>Leuciscus leuciscus</it>) for 503 individuals (440 purebred specimens and 63 hybrids) from 15 European cyprinid species. The level of genetic diversity was assessed in <it>Alburnus alburnus, Alburnoides bipunctatus, C. genei, C. n. nasus, C. soetta, C. t. toxostoma, L. idus, L. leuciscus, Pachychilon pictum, Rutilus rutilus, Squalius cephalus </it>and <it>Telestes souffia</it>. The applicability of the markers was also tested on <it>Abramis brama, Blicca bjoerkna </it>and <it>Scardinius erythrophtalmus </it>specimens. Overall, between 24 and 37 of these markers revealed polymorphic for the investigated species and 23 markers amplified for all the 15 European cyprinid species.</p> <p>Conclusions</p> <p>The developed set of markers demonstrated its performance in discriminating European cyprinid species. Furthermore, it allowed detecting and characterizing hybrid individuals. These microsatellites will therefore be useful to perform comparative evolutionary and population genetics studies dealing with European cyprinids, what is of particular interest in conservation issues and constitutes a tool of choice to conduct hybridization studies.</p