Structured sparsity for spatially coherent fibre orientation estimation in diffusion MRI.

We propose a novel formulation to solve the problem of intra-voxel reconstruction of the fibre orientation distribution function (FOD) in each voxel of the white matter of the brain from diffusion MRI data. The majority of the state-of-the-art methods in the field perform the reconstruction on a voxel-by-voxel level, promoting sparsity of the orientation distribution. Recent methods have proposed a global denoising of the diffusion data using spatial information prior to reconstruction, while others promote spatial regularisation through an additional empirical prior on the diffusion image at each q-space point. Our approach reconciles voxelwise sparsity and spatial regularisation and defines a spatially structured FOD sparsity prior, where the structure originates from the spatial coherence of the fibre orientation between neighbour voxels. The method is shown, through both simulated and real data, to enable accurate FOD reconstruction from a much lower number of q-space samples than the state of the art, typically 15 samples, even for quite adverse noise conditions.

International Expansion, Diversification and Regulated Firm Nonmarket Strategy

Previous studies have shown that regulated firms diversify for reasons that are different than for unregulated firms. We explore some of these differences by providing a theoretical model that starts by considering the firm-regulator relationship as an incomplete information issue, in which a regulated incumbent has knowledge that the regulator does not have, but the firm cannot convey hard information about this knowledge. The incumbent faces both market and nonmarket competition from a new entrant. In that context, we show that when the firm faces tough nonmarket competition domestically, going abroad can create a mechanism that makes information transmission to the regulator more credible. International expansion can thus be a way to solve domestic nonmarket issues in addition to being a catalyst for growth.

What role do just-world beliefs play in harmful responses to injustice?

Research suggests that employees sometimes retaliate and sometimes refrain from retaliation for the same reason, namely because they care about justice. In two studies, we seek to solve this apparent inconsistency. Drawing on just world theory, we argue that retaliatory, harmful behavioral strategies to deal with injustice are associated to individual differences in personal belief in a just world (personal BJW). In contrast, individual differences in believing that the world is just in general (general BJW) are linked to the inhibition of these reactions. As a consequence, the relation between injustice and harmful behaviors is stronger for people with a high personal BJW than for those with a low one. General BJW is associated with their inhibition such that the relation between injustice and harmful reactions is weaker for people with a high general BJW than for those with a low one. We found evidence for our hypotheses in a cross-sectional field study and an experiment. We discuss our findings in light of their implications for just-world theory and suggest avenues for future research integrating organizational justice literature.

Histoire de packs ou d'enveloppes thérapeutiques avec un patient dément

Les patients déments, comme les patients psychotiques, peuvent présenter des angoisses d'intrusion ou de morcellement. L'histoire de Monsieur D témoigne du fait que les packs permettent de diminuer cette souffrance en offrant une expérience intense de contenance et d'unité. Malgré une démence avancée, Monsieur D a ainsi pu intégrer progressivement cette enveloppe maternante et thérapeutique pour recréer le lien à l'autre et le lien à lui-même.

Correcting surface coil excitation inhomogeneities in single-shot SPEN MRI.

Given their high sensitivity and ability to limit the field of view (FOV), surface coils are often used in magnetic resonance spectroscopy (MRS) and imaging (MRI). A major downside of surface coils is their inherent radiofrequency (RF) B1 heterogeneity across the FOV, decreasing with increasing distance from the coil and giving rise to image distortions due to non-uniform spatial responses. A robust way to compensate for B1 inhomogeneities is to employ adiabatic inversion pulses, yet these are not well adapted to all imaging sequences - including to single-shot approaches like echo planar imaging (EPI). Hybrid spatiotemporal encoding (SPEN) sequences relying on frequency-swept pulses provide another ultrafast MRI alternative, that could help solve this problem thanks to their built-in heterogeneous spatial manipulations. This study explores how this intrinsic SPEN-based spatial discrimination, could be used to compensate for the B1 inhomogeneities inherent to surface coils. Experiments carried out in both phantoms and in vivo rat brains demonstrate that, by suitably modulating the amplitude of a SPEN chirp pulse that progressively excites the spins in a direction normal to the coil, it is possible to compensate for the RF transmit inhomogeneities and thus improve sensitivity and image fidelity.

Types of stereoselectivity in drug metabolism: a heuristic approach.

Stereochemical factors are known to play a significant role in the metabolism of drugs and other xenobiotics. Following Prelog's lead, types of metabolic stereoselectivity can be categorized as (i) substrate stereoselectivity (the differential metabolism of two or more stereoisomeric substrates) and (ii) product stereoselectivity (the differential formation of two or more stereoisomeric metabolites from a single substrate). Combinations of the two categories exist as (iii) substrate-product stereoselectivities, meaning that product stereoselectivity itself is substrate stereoselective. Here, published examples of metabolic stereoselectivities are examined in the light of these concepts. In parallel, a graphical scheme is presented with a view to facilitate learning and help researchers to solve classification problems.

Rotation mentale et différences sexuelles: influence des axes directionnels extraits de l'environnement

Les tâches nécessitant des manipulations et des transformations de figures géométriques et de formes, comme les tâches de rotation mentale, donnent lieu à des différences de performance entre hommes et femmes qui restent intrigantes. Plusieurs hypothèses ont été proposées pour expliquer ces différences. La plus récurrente porte sur les différences de stratégie globale vs locale utilisées pour traiter l'information. Bien que cette conjecture soit intéressante, elle reste difficile à opérationnaliser car elle englobe tous les mécanismes cognitifs (acquisition, conservation et récupération de l'information). Ce travail prend la forme d'un retour aux sources dans la mesure où il se base sur des recherches anciennes qui ont montré que les hommes perçoivent significativement mieux que les femmes la verticale et l'horizontale. Il teste l'hypothèse selon laquelle les hommes, comparativement aux femmes, présentent une plus forte indépendance au champ perceptif visuel et sont donc plus susceptibles d'utiliser la verticalité et l'horizontalité pour résoudre une tâche de rotation mentale. Une première série d'expériences s'est penchée sur la perception spatiale pour évaluer son impact sur la résolution d'une tâche impliquant la rotation mentale. Les résultats ont montré que seuls les hommes se référaient à la verticalité et à l'horizontalité pour résoudre la tâche. Une seconde série d'expériences ont investigué l'effet de la présence, ou absence, d'axes directionnels directement liés à une tâche de rotation mentale. Elles ont été menées également en environnement réel afin d'évaluer comment le déplacement actif ou passif, correspondant à un changement de perspective en lieu et place d'une rotation mentale, module la performance des hommes et des femmes. Les résultats n'ont pas mis en évidence de différence sexuelle. Notre hypothèse est vérifiée puisque c'est uniquement lorsque la tâche ne présente pas d'axes orthogonaux évidents mais implicites que seuls les hommes, plus indépendants au champ perceptif visuel que les femmes, utilisent la perception de la verticalité et de l'horizontalité pour améliorer leur compétence en rotation mentale. -- Tasks that require manipulation and transformation of geometric shapes and forms, like tasks of mental rotation and give rise to differences in performance between men and women, remain intriguing. Several hypotheses have been proposed to explain these differences. The most recurring hypothesis addresses differences in global versus local strategies for processing information. While this conjecture is interesting, it remains difficult to study because it encompasses all the cognitive mechanisms (acquisition, retention and output). This work returns to the sources, which are based on earlier research that shows that men are significantly better than women at perceiving verticality and horizontality. It tests the hypothesis according to which men, as compared to women, exhibit a greater independence on the perceptive visual field, and therefore are more susceptible to utilizing the verticality and the horizontality to solve a mental rotation task. A first set of experiments examined spatial perception in order to assess its impact on the resolution of a task involving mental rotation. The results showed that only men referred to the verticality and the horizontality to solve the task. A second series of experiments investigated the effect of a presence, or absence of directional axes directed tied to the task of mental rotation. They were also conducted in a real world environment to evaluate how the active or passive displacement, corresponding to a change in perspective instead of a mental rotation, modulates the performance of men and women. The results did not show sex differences. Our hypothesis is verified: it is only when the task presents no obvious, but implicit orthogonal axes that men, who exhibit a greater independence on the perceptive visual field than women, use the perception of verticality and horizontality to improve their competence in mental rotation.

Cerebriforms cells in cerebrum: an unusual finding

Background. Mycosis Fungoides (MF) is the most common cutaneous T-cell lymphoma, and large cell trasformation (tMF) is an adverse prognostic event. Extra-cutaneous dissemination can occur in the course of the disease, but dissemination to the central nervous system (CNS) is uncommon. Moreover, CNS lymphomas are overall rare and most often of B-cell phenotype. We report a case of CNS large T-cell lymphoma presenting as multiple cerebral lesions in a patient with a history of MF. Methods. We report a case of a 33-year-old woman, known since the age of 16 for erythematous plaques thought to be atopic dermatitis, who developed, end 2012, multiple nodular skin lesions and peripheral adenopathies. Two skin lesions were biopsied simultaneously, and diagnosed as MF and tMF. A lymph node biopsy showed dermatopathic changes without lymphoma (Stage IIB). She received local treatment (UVB, PUVA and radiation therapy) and interferon therapy, and experienced almost complete remission. In 2015 neurological symptoms lead to evidence multiple cerebral lesions, suspicious for lymphoma, evaluated by stereotaxic biopsies. We compared histopathological and molecular features of these with previous skin specimens. After negative bone marrow staging biopsy, she was recently started on chemotherapy (MATRIX). Short follow-up shows rapidly worsening clinical conditions. Results. One of the initial skin biopsies showed atypical lymphoid cells with epidermotropism, Pautrier abcesses and CD4+ CD30- phenotype; the other revealed diffuse dermal infiltration by predominantly large cerebriform tumor cells with high proliferative fraction, and CD2−CD3 −CD4+/−CD7−CD30+ALK- EMA- non-cytotoxic immunophenotype. Altogether, these results led us to diagnose MF and tMF, respectively. The brain was infiltrated by large atypical lymphoid cells with cerebriform nuclei, somewhat anaplastic features and perivascular distribution. By immunohistochemistry, tumor cells were highly proliferative, with a CD2−CD3+CD5−CD7+CD30+ activated cytotoxic immunophenotype. A diagnosis of CD30+ cytotoxic peripheral T-cell lymphoma was retained. TRG and TRB clonality analyses revealed clonal rearrangements in skin and CNS biopsies, with identical patterns in both skin specimens but only minimally overlapping profiles when compared to the CNS sample. Der Pathologe 6 ? 2015 | 633 Conclusions. The reported case illustrates an uncommon finding of a CNS T-cell lymphoma in a patient with previous MF, questioning the clonal relationship between the two diseases and challenging the adequate classification of this CNS lymphoma as either a progression or a de novo lymphoma. Despite differences in immunophenotype and clonality patterns, this CNS lymphoma could possibly represent an aggressive divergent evolution of a primary cutaneous T-cell lymphoma. Additional sequencing is ongoing to try to solve the question.

Services "amis des jeunes": promouvoir des soins adaptés aux adolescents [Youth friendly health services: how to promote quality health care for adolescents].

Beaucoup de jeunes éprouvent des difficultés à demander une aide médicale et psychosociale alors qu'ils en auraient bien besoin. Cela est lié au processus d'autonomisation propre à cette période de la vie : les adolescents souhaitent résoudre leurs problèmes eux-mêmes. Pour améliorer la qualité des soins aux jeunes, l'Organisation mondiale de la santé, avec l'UNICEF et d'autres organismes, a développé le concept de youth friendly health services ; services amis des jeunes. Ce concept repose sur plusieurs principes, comme l'accessibilité, la flexibilité, une formation spécifique du personnel, le respect de la neutralité et de la confidentialité, compétences communicationnelles, etc. L'application de cette approche ne se limite pas aux centres spécialisés en médecine de l'adolescence, mais devra être progressivement implantée dans toutes les structures de soins accueillant des jeunes. Many young people have difficulties requesting medical or psychosocial support, although some badly need it. This difficulty is related to the fact that, as part of their search for autonomy, young people prefer to solve their problems by themselves. To improve the quality of care, the World Health Organization, UNICEF and allied organizations have developed the concept of "Youth friendly health services". This concept includes policies and strategies to improve the accessibility and flexibility, staff's competence and communication skills, etc. Such an approach should not be limited to specialized centers for adolescent health. It should be adopted by all health care institutions dealing with young people.

A minimal set of coordinates for describing humanoid shoulder motion

The kinematics of the anatomical shoulder are analysed and modelled as a parallel mechanism similar to a Stewart platform. A new method is proposed to describe the shoulder kinematics with minimal coordinates and solve the indeterminacy. The minimal coordinates are defined from bony landmarks and the scapulothoracic kinematic constraints. Independent from one another, they uniquely characterise the shoulder motion. A humanoid mechanism is then proposed with identical kinematic properties. It is then shown how minimal coordinates can be obtained for this mechanism and how the coordinates simplify both the motion-planning task and trajectory-tracking control. Lastly, the coordinates are also shown to have an application in the field of biomechanics where they can be used to model the scapulohumeral rhythm.

Care delivery value chains for ophthalmic clinics in Switzerland

Perceived patient value is often not aligned with the emerging expenses for health care services. In other words, the costs are often supposed as rising faster than the actual value for the patients. This fact is causing major concerns to governments, health plans, and individuals. Attempts to solve the problem have habitually been on the operational effectiveness side: increasing patient volume, minimizing costs, rationing, or closing hospitals, usually resulting in a zero-sum game. Only few approaches come from the strategic positioning side and "competition" among hospitals is still perceived rather as a danger than as a chance to create a positive-sum game and stimulate patient value. In their 2006 book, "Redefining Health Care", the renowned Harvard strategy professor Michael E. Porter and hospital management expert Professor Elizabeth Olmsted Teisberg approach the challenge from the positive-sum perspective: they propose to form Integrated Practice Units (IPUs) and manage hospitals in a modern, patient value oriented way. They argue that creating value-based competition on results should have the same effect on the health care sector like transparency and competition turned other industries with out-dated management models (like recently the inert telecommunication industry) into highly competitive and customer value creating businesses. The objective of this paper is to elaborate Care Delivery Value Chains for Integrated Practice Units in ophthalmic clinics and gather a first feedback from Swiss hospital managers, ophthalmologists, and patients, if such an approach could be a realistic way to improve health care management. First, Porter's definition of competitiveness (distinction between operational effectiveness and strategic positioning) is explained. Then, the Care Delivery Value Chain is introduced as a key element for understanding value-based management, followed by three practice examples for ophthalmic clinics. Finally, recommendations are given how the Care Delivery Value Chain can be managed efficiently and how the obstacles of becoming a patient-oriented organization can be overcome. The conclusion is that increased transparency and value-based competition on results has the potential to change the mindset of hospital managers-which will align patient value with the emerging health care expenses. Early adapters of this management approach will gain a competitive advantage. [Author, p. 6]