Le rôle du raisonnement inductif dans le trouble délirant

Pour faire un diagnostic différentiel qui distingue entre les croyances obsessionnelles et celles du trouble délirant (TD), un aspect crucial à évaluer est l’intensité avec laquelle cette conviction est maintenue, allant du doute dans le trouble obsessionnel-compulsif (TOC) à la certitude dans le TD. En effet, les personnes ayant un TD semblent se fier davantage à leur imagination parce qu’elles ne peuvent pas faire confiance aux autres ou à la réalité. Dans le TOC, les personnes croient que leurs doutes imaginaires sont de réelles probabilités, de sorte qu’elles ne peuvent prendre le risque que ces probabilités surviennent réellement. Dans les deux cas, le problème n’est pas la distorsion perceptuelle, mais le remplacement de la réalité par une histoire imaginée et perçue comme possible, même jusqu’à être réelle. Pélissier et O’Connor (2002) ont démontré que les personnes ayant un TOC montrent un style de raisonnement inductif particulier en comparaison de celui des groupes contrôles. Ainsi, l’exploration du raisonnement inductif dans le cas des personnes qui ont un TD permettrait peut-être de raffiner notre compréhension de la pensée délirante, et d’améliorer éventuellement les stratégies de la thérapie cognitive pour le TD. Il est recommandé que les études futures sur le TD essaient de mieux comprendre le raisonnement inductif ainsi que le rôle de l’imagination prédisposant au développement des délires.Differential diagnosis between obsessive beliefs in obsessive-compulsive disorder (OCD) and delusions in delusional disorder (DD) requires distinguishing the strength of conviction with which the person holds these beliefs, that is : a dimension stretching from doubt to certainty. Effectively, individuals with DD seem to rely much more on their imagination since they cannot trust others or reality. In OCD, people believe that their imaginary doubts are real probabilities and they cannot take the risk that these possibilities occur in reality. In both cases, the problem is not perceptual distortion but the replacement of reality by an imaginary story perceived as possible or even real. Pelissier and O’Connor (2002) have demonstrated that people with OCD show a particular inductive reasoning style when compared to control groups. Hence, exploration of inductive reasoning in the cases of people with DD could possibly enrich our comprehension of delusional thinking and further improve our strategies in cognitive therapy. It is recommended that future studies on DD concentrate on further understanding of inductive reasoning and the role of imagination predisposing the development of delusions.Para realizar un diagnóstico diferencial que distinga entre las creencias obsesivas y aquellas del trastorno delirante (TD), es crucial evaluar la intensidad con la que esta convicción se mantiene, yendo de la duda en el trastorno obsesivocompulsivo (TOC) a la certeza en el TD. De hecho, las personas con un TD parecen fiarse más de su imaginación porque no pueden confiar en los demás o en la realidad. En el TOC, las personas creen que sus dudas imaginarias son probabilidades reales, de manera que no pueden tomar el riesgo de que estas probabilidades ocurran realmente. En ambos casos, el problema no es la distorsión de la percepción, sino el reemplazo de la realidad por una historia imaginaria y percibida como posible, incluso hasta que llega a ser real. Pélissier y O’Connor (2002) demostraron que las personas que sufren de TOC muestran un estilo de razonamiento inductivo particular, en comparación con el de los grupos de control. De esta manera, la exploración del razonamiento inductivo en los casos de las personas que sufren de un TD permitiría tal vez afinar nuestra comprensión del pensamiento delirante y mejorar eventualmente las estrategias de la terapia cognitiva para el TD. Se recomienda que los estudios futuros sobre el TD intenten comprender mejor el razonamiento inductivo, así como el papel de la imaginación que predispone al desarrollo de los delirios.Para fazer um diagnóstico diferencial que distingue as crenças obsessivas das crenças do transtorno delirante (TD), um aspecto crucial a avaliar é a intensidade com a qual esta convicção é mantida, indo da dúvida no transtorno obsessivo-compulsivo (TOC) à certeza no TD. De fato, as pessoas que sofrem de TD parecem acreditar mais em sua imaginação, visto que não podem confiar nos outros ou na realidade. No TOC, as pessoas crêem que suas dúvidas imaginárias são reais probabilidades, de maneira que elas não podem arriscar que estas probabilidades aconteçam realmente. Nos dois casos, o problema não é a distorção percepcional, mas a substituição da realidade por uma história imaginada e vista como possível, mesmo até real. Pélissier e O’Connor (2002) demonstraram que as pessoas que sofrem de TOC apresentam um estilo de raciocínio indutivo particular em comparação com o dos grupos de controle. Assim, a exploração do raciocínio indutivo, no caso das pessoas que sofrem de TD, permitiria talvez especificar nossa compreensão do pensamento delirante, e melhorar eventualmente as estratégias da terapia cognitiva para o TD. Recomenda-se que os estudos futuros sobre o TD busquem melhor compreender o raciocínio indutivo, assim como o papel da imaginação que predispõe ao desenvolvimento dos delírios

Growth rings in tropical trees : role of functional traits, environment, and phylogeny

Acknowledgments Financial support of the Centre National de la Recherche Scientifique (USR 3330), France, and from the Rufford Small Grants Foundation (UK) is acknowledged. We thank the private farmers and coffee plantation companies of Kodagu for providing permissions and logistical support for this project. We are grateful to N. Barathan for assistance with slide preparation and data entry, S. Aravajy for botanical assistance, S. Prasad and G. Orukaimoni for technical inputs, and A. Prathap, S. Shiva, B. Saravana, and P. Shiva for field assistance. The corresponding editor and three anonymous reviewers provided insightful comments that improved the manuscript.Peer reviewedPostprin

Predicting tropical forest stand structure parameters from Fourier transform of very high-resolution remotely sensed canopy images

1. Predicting stand structure parameters for tropical forests from remotely sensed data has numerous important applications, such as estimating above-ground biomass and carbon stocks and providing spatial information for forest mapping and management planning, as well as detecting potential ecological determinants of plant species distributions. As an alternative to direct measurement of physical attributes of the vegetation and individual tree crown delineation, we present a powerful holistic approach using an index of canopy texture that can be extracted from either digitized air photographs or satellite images by means of two-dimensional spectral analysis by Fourier transform. 2. We defined an index of canopy texture from the ordination of the Fourier spectra computed for 3545 1-ha square images of an undisturbed tropical rain forest in French Guiana. This index expressed a gradient of coarseness vs. fineness resulting from the relative importance of small, medium and large spatial frequencies in the Fourier spectra. 3. Based on 12 1-ha control plots, the canopy texture index showed highly significant correlations with tree density (R2 = 0·80), diameter of the tree of mean basal area (R2 = 0·71), distribution of trees into d.b.h. classes (R2 = 0·64) and mean canopy height (R2 = 0·57), which allowed us to produce reasonable predictive maps of stand structure parameters from digital aerial photographs. 4. Synthesis and applications. Two-dimensional Fourier analysis is a powerful method for obtaining quantitative characterization of canopy texture, with good predictive ability on stand structure parameters. Forest departments should use routine forest inventory operations to set up and feed regional databases, featuring both tree diameter figures and digital canopy images, with the ultimate aims of calibrating robust regression relationships and deriving predictive maps of stand structure parameters over large areas of tropical forests. Such maps would be particularly useful for forest classification and to guide field assessment of tropical forest resources and biodiversity

Computing the first eigenpair of the p-Laplacian via inverse iteration of sublinear supersolutions

We introduce an iterative method for computing the first eigenpair $(\lambda_{p},e_{p})$ for the $p$-Laplacian operator with homogeneous Dirichlet data as the limit of $(\mu_{q,}u_{q})$ as $q\rightarrow p^{-}$, where $u_{q}$ is the positive solution of the sublinear Lane-Emden equation $-\Delta_{p}u_{q}=\mu_{q}u_{q}^{q-1}$ with same boundary data. The method is shown to work for any smooth, bounded domain. Solutions to the Lane-Emden problem are obtained through inverse iteration of a super-solution which is derived from the solution to the torsional creep problem. Convergence of $u_{q}$ to $e_{p}$ is in the $C^{1}$-norm and the rate of convergence of $\mu_{q}$ to $\lambda_{p}$ is at least $O(p-q)$. Numerical evidence is presented.Comment: Section 5 was rewritten. Jed Brown was added as autho

Separate and combined analysis of successive dependent outcomes after breast-conservation surgery: recurrence, metastases, second cancer and death

<p>Abstract</p> <p>Background</p> <p>In the setting of recurrent events, research studies commonly count only the first occurrence of an outcome in a subject. However this approach does not correctly reflect the natural history of the disease. The objective is to jointly identify prognostic factors associated with locoregional recurrences (LRR), contralateral breast cancer, distant metastases (DM), other primary cancer than breast and breast cancer death and to evaluate the correlation between these events.</p> <p>Methods</p> <p>Patients (n = 919) with a primary invasive breast cancer and treated in a cancer center in South-Western France with breast-conserving surgery from 1990 to 1994 and followed up to January 2006 were included. Several types of non-independent events could be observed for the same patient: a LRR, a contralateral breast cancer, DM, other primary cancer than breast and breast cancer death. Data were analyzed separately and together using a random-effects survival model.</p> <p>Results</p> <p>LRR represent the most frequent type of first failure (14.6%). The risk of any event is higher for young women (less than 40 years old) and in the first 10 years of follow-up after the surgery. In the combined analysis histological tumor size, grade, number of positive nodes, progesterone receptor status and treatment combination are prognostic factors of any event. The results show a significant dependence between these events with a successively increasing risk of a new event after the first and second event. The risk of developing a new failure is greatly increased (RR = 4.25; 95%CI: 2.51-7.21) after developing a LRR, but also after developing DM (RR = 3.94; 95%CI: 2.23-6.96) as compared to patients who did not develop a first event.</p> <p>Conclusion</p> <p>We illustrated that the random effects survival model is a more satisfactory method to evaluate the natural history of a disease with multiple type of events.</p

Test of a theoretical equation of state for elemental solids and liquids

We propose a means for constructing highly accurate equations of state (EOS) for elemental solids and liquids essentially from first principles, based upon a particular decomposition of the underlying condensed matter Hamiltonian for the nuclei and electrons. We also point out that at low pressures the neglect of anharmonic and electron-phonon terms, both contained in this formalism, results in errors of less than 5% in the thermal parts of the thermodynamic functions. Then we explicitly display the forms of the remaining terms in the EOS, commenting on the use of experiment and electronic structure theory to evaluate them. We also construct an EOS for Aluminum and compare the resulting Hugoniot with data up to 5 Mbar, both to illustrate our method and to see whether the approximation of neglecting anharmonicity et al. remains viable to such high pressures. We find a level of agreement with experiment that is consistent with the low-pressure results.Comment: Minor revisions for consistency with published versio

SINE RNA Induces Severe Developmental Defects in Arabidopsis thaliana and Interacts with HYL1 (DRB1), a Key Member of the DCL1 Complex

The proper temporal and spatial expression of genes during plant development is governed, in part, by the regulatory activities of various types of small RNAs produced by the different RNAi pathways. Here we report that transgenic Arabidopsis plants constitutively expressing the rapeseed SB1 SINE retroposon exhibit developmental defects resembling those observed in some RNAi mutants. We show that SB1 RNA interacts with HYL1 (DRB1), a double-stranded RNA-binding protein (dsRBP) that associates with the Dicer homologue DCL1 to produce microRNAs. RNase V1 protection assays mapped the binding site of HYL1 to a SB1 region that mimics the hairpin structure of microRNA precursors. We also show that HYL1, upon binding to RNA substrates, induces conformational changes that force single-stranded RNA regions to adopt a structured helix-like conformation. Xenopus laevis ADAR1, but not Arabidopsis DRB4, binds SB1 RNA in the same region as HYL1, suggesting that SINE RNAs bind only a subset of dsRBPs. Consistently, DCL4-DRB4-dependent miRNA accumulation was unchanged in SB1 transgenic Arabidopsis, whereas DCL1-HYL1-dependent miRNA and DCL1-HYL1-DCL4-DRB4-dependent tasiRNA accumulation was decreased. We propose that SINE RNA can modulate the activity of the RNAi pathways in plants and possibly in other eukaryotes

Variables with time-varying effects and the Cox model: Some statistical concepts illustrated with a prognostic factor study in breast cancer

International audienceBACKGROUND: The Cox model relies on the proportional hazards (PH) assumption, implying that the factors investigated have a constant impact on the hazard - or risk - over time. We emphasize the importance of this assumption and the misleading conclusions that can be inferred if it is violated; this is particularly essential in the presence of long follow-ups. METHODS: We illustrate our discussion by analyzing prognostic factors of metastases in 979 women treated for breast cancer with surgery. Age, tumour size and grade, lymph node involvement, peritumoral vascular invasion (PVI), status of hormone receptors (HRec), Her2, and Mib1 were considered. RESULTS: Median follow-up was 14 years; 264 women developed metastases. The conventional Cox model suggested that all factors but HRec, Her2, and Mib1 status were strong prognostic factors of metastases. Additional tests indicated that the PH assumption was not satisfied for some variables of the model. Tumour grade had a significant time-varying effect, but although its effect diminished over time, it remained strong. Interestingly, while the conventional Cox model did not show any significant effect of the HRec status, tests provided strong evidence that this variable had a non-constant effect over time. Negative HRec status increased the risk of metastases early but became protective thereafter. This reversal of effect may explain non-significant hazard ratios provided by previous conventional Cox analyses in studies with long follow-ups. CONCLUSIONS: Investigating time-varying effects should be an integral part of Cox survival analyses. Detecting and accounting for time-varying effects provide insights on some specific time patterns, and on valuable biological information that could be missed otherwise