Rota's universal operators and invariant subspaces in Hilbert spaces

A Hilbert space operator is called universal (in the sense of Rota) if every operator on the Hilbert space is similar to a multiple of the restriction of the universal operator to one of its invariant subspaces. We exhibit an analytic Toeplitz operator whose adjoint is universal in the sense of Rota and commutes with a quasi-nilpotent injective compact operator with dense range. In particular, this new universal operator invites an approach to the Invariant Subspace Problem that uses properties of operators that commute with the universal operator.

Equivalent norms in polynomial spaces and applications.

In this paper, equivalence constants between various polynomial norms are calculated. As an application, we also obtain sharp values of the Hardy Littlewood constants for 2-homogeneous polynomials on l(p)(2) spaces, 2 < p <= infinity. We also provide lower estimates for the Hardy-Littlewood constants for polynomials of higher degrees.

Lighting ambiances and materialities of wood in architecture: a comparative evaluation of the quality of spaces in relation to interior finishes

Le bois est un matériau souvent utilisé par les architectes pour améliorer l’ambiance générale d’un espace, mais peu de recherches en présentent l’impact réel du matériau sur les impressions visuelles et les effets lumineux. Cette recherche étudie l’influence de la matérialité du bois par rapport à la création d’ambiances d’éclairage spécifiques dans l’architecture. Plus particulièrement, elle se concentre sur l’impact des panneaux décoratifs en bois à générer de la diversité lumineuse dans les espaces intérieurs et son potentiel à améliorer la satisfaction environnementale et l’efficacité énergétique. La recherche utilise des maquettes à l’échelle pour leur précision dans la représentation des ambiances lumineuses d’espaces éclairés naturellement ainsi que les technologies récentes d’imagerie digitale pour capturer et analyser les résultats. La méthodologie permet la comparaison entre les différents réglages des espaces intérieurs créés par une sélection des types de matérialités du bois: la réflectance (valeur), la couleur et la réflectivité. Les modalités spatiales sont comparées en présence d’ensoleillement direct et sous des conditions de ciel couvert puisque les modèles d’éclairage et les ambiances diffèrent considérablement. Les résultats permettent d’établir une discussion sur les ambiances en termes de brillance et de contraste, sur la couleur ainsi que la répartition des zones lumineuses dans l’espace. La recherche souligne le rôle des matérialités que peuvent prendre le bois pour optimiser la diversité lumineuse et la création d’ambiances visuellement confortables, ainsi que ses possibilités d’améliorer les ambiances architecturales par rapport à la lumière.

Dissecting the role of IGF2BP3 in the stress-adaptive response and in intercellular communication in Ewing Sarcoma.

Tumor microenvironment has emerged as key factor influencing tumor progression and metastatization. In this context, small vesicles produced by cancer cells can influence the fate of their surroundings via the horizontal transfer of specific molecular cargos. Ewing Sarcoma, the second most common bone tumor in young patients, presents early metastasis associated to worse prognosis. The RNA binding protein Insulin-like Growth Factor 2 mRNA Binding Protein 3 (IGF2BP3) exerts a pro-oncogenic role associated with metastasis formation and worse prognosis in Ewing Sarcoma. Our aim was to investigate the still unexplored role of IGF2BP3 in the stress-adaptive response to tumor microenvironment and in the interactions between Ewing Sarcoma cells. Hypoxia is a major feature of Ewing Sarcoma microenvironment and we demonstrated that IGF2BP3 can direct the CXCR4-mediated migratory response to CXCL12 in Ewing Sarcoma cells subjected to oxygen deprivation. We also discovered that the interaction between IGF2BP3 and CXCR4 is regulated through CD164 and which colocalize at plasma membrane level, upon CXCL12 exposure. Interestingly, high IGF2BP3 levels in Ewing Sarcoma metastatic lesions positively correlated with the expression of both CD164 and CXCR4, indicating the IGF2BP3/CD164/CXCR4 oncogenic axis as a critical modulator of Ewing Sarcoma metastatic progression. We demonstrated for the first time that IGF2BP3 is loaded into Ewing Sarcoma derived exosomes, accordingly to its cellular levels. We discovered that IGF2BP3+ exosomes carry high levels of IGF2BP3-client mRNAs involved in cellular migration, CD164 and IGF1R, and, by transferring this cargo, sustain the migratory abilities of receiving cells, induce a sharp up-regulation of CD164, CXCR4 and IGF1R and enhance the activation of AKT/mTOR and ERK down-stream signalling pathways. We demostrated that the pro-tumorigenic role of IGF2BP3 is not only exerted at cellular level, but that intercellular communication is crucial in the context of Ewing Sarcoma microenvironment.

Influence of the natural environment on health: evaluation of different environmental contexts (urban, green spaces) and intervention proposals

Urbanization has grown during the last decades, with an increase in population concentrated in cities. Cities are usually relatively nature-poor, and the loss of green urban space likely leads to less contact with the natural world for urban dwellers. It is known that the natural environment could provide important advantages, and the loss of contact with this type of environment has potential negative impacts on the quality of life. The use of green urban space demonstrated stronger benefits for mental health and stress reduction. In general, exposure to green urban space is linked to a reduction in mortality rates, due to the promotion of a healthy lifestyle. Green urban space could be an optimal environment in which to perform physical activity. Undertaking regular physical activity is one of the major determinants of health. The benefits of exercise have been widely demonstrated through a wide range of studies. Benefits are linked to the treatment and prevention of most chronic and non-communicable diseases, that are not contagious, but they are usually long-lasting. Regular physical activity could reduce mental health problems, such as anxiety. The World Health Organization proposed to improve physical activity programs through the implementation of interventions in green urban spaces. Green urban space provides a safe, accessible, and attractive place to perform physical activity. All the interventions aimed to promote the practice of physical activity and to reduce sedentary behavior are important. It is well known that physical activity has several positive effects, a great amount of the population remains inactive. A good strategy could be to show people how integrated physical activity into their all-day life, for example through the use of green urban space or active commuting. The results in the present thesis showed the effectiveness of performing physical activity in a natural environment and of active commuting.

Coworking spaces: thriving and organizing in the new world of work

The present Ph.D. thesis proposes three studies on coworking spaces to understand how they foster thriving and organizing in the new world of work. The first study maps and analyzes the thematic structure and evolution of the academic debate that has emerged around coworking spaces in recent years. In doing so, it conducts a science mapping analysis of 351 publications on coworking spaces to detect and visualize key themes in the literature and their co-occurrence with subthemes. The second study proposes an interpretive review of 98 publications from multiple disciplines to shed light on how coworking spaces emerge as sites of organizing for professionals who are not formally connected to one another. It suggests five dimensions that articulate coworking spaces as sites of organizing – ‘materiality,’ ‘temporality,’ ‘affect,’ ‘identity,’ and ‘formalization.’ This study aims to go beyond the community-related understanding of coworking that has characterized most scholarly attention, instead focusing on coworking spaces’ organizational character. The third study investigates what drives thriving at work for remote workers in coworking spaces. In doing so, it acknowledges the potential complex set of interrelationships underpinning thriving at work and mobilizes complexity theory and qualitative comparative analysis to uncover six different, yet equifinal, configurations of antecedents driving remote workers’ thriving in coworking spaces.

Potential theory on metric spaces

This work revolves around potential theory in metric spaces, focusing on applications of dyadic potential theory to general problems associated to functional analysis and harmonic analysis. In the first part of this work we consider the weighted dual dyadic Hardy's inequality over dyadic trees and we use the Bellman function method to characterize the weights for which the inequality holds, and find the optimal constant for which our statement holds. We also show that our Bellman function is the solution to a stochastic optimal control problem. In the second part of this work we consider the problem of quasi-additivity formulas for the Riesz capacity in metric spaces and we prove formulas of quasi-additivity in the setting of the tree boundaries and in the setting of Ahlfors-regular spaces. We also consider a proper Harmonic extension to one additional variable of Riesz potentials of functions on a compact Ahlfors-regular space and we use our quasi-additivity formula to prove a result of tangential convergence of the harmonic extension of the Riesz potential up to an exceptional set of null measure

Power in public art spaces. F(r)ictions, performativity and the generation of counter-hegemonic narratives

Abstract This thesis applies queer theories to the examination of experiences which go beyond queerness. Queer, decolonial, antiracist and feminist new materialist concepts are implemented to the analysis of four case studies dealing with power and art in public spaces. By applying concepts as methodologies, autoethnographic reflections and f(r)ictions as research alternatives, the thesis brings up new diffractive readings from where to perform those scenarios differently. In doing so, the thesis disentangles the historical, material, philosophical, political and disruptive meanings which haunt the four case studies and triggers the artivist potential of their counter-hegemonic narratives.

Evidences Of Endocytosis Via Caveolae Following Blood-brain Barrier Breakdown By Phoneutria Nigriventer Spider Venom.

Spider venoms contain neurotoxic peptides aimed at paralyzing prey or for defense against predators; that is why they represent valuable tools for studies in neuroscience field. The present study aimed at identifying the process of internalization that occurs during the increased trafficking of vesicles caused by Phoneutria nigriventer spider venom (PNV)-induced blood-brain barrier (BBB) breakdown. Herein, we found that caveolin-1α is up-regulated in the cerebellar capillaries and Purkinje neurons of PNV-administered P14 (neonate) and 8- to 10-week-old (adult) rats. The white matter and granular layers were regions where caveolin-1α showed major upregulation. The variable age played a role in this effect. Caveolin-1 is the central protein that controls caveolae formation. Caveolar-specialized cholesterol- and sphingolipid-rich membrane sub-domains are involved in endocytosis, transcytosis, mechano-sensing, synapse formation and stabilization, signal transduction, intercellular communication, apoptosis, and various signaling events, including those related to calcium handling. PNV is extremely rich in neurotoxic peptides that affect glutamate handling and interferes with ion channels physiology. We suggest that the PNV-induced BBB opening is associated with a high expression of caveolae frame-forming caveolin-1α, and therefore in the process of internalization and enhanced transcytosis. Caveolin-1α up-regulation in Purkinje neurons could be related to a way of neurons to preserve, restore, and enhance function following PNV-induced excitotoxicity. The findings disclose interesting perspectives for further molecular studies of the interaction between PNV and caveolar specialized membrane domains. It proves PNV to be excellent tool for studies of transcytosis, the most common form of BBB-enhanced permeability.

Interplay Between Cell Growth And Cell Cycle In Plants.

The growth of organs and whole plants depends on both cell growth and cell-cycle progression, but the interaction between both processes is poorly understood. In plants, the balance between growth and cell-cycle progression requires coordinated regulation of four different processes: macromolecular synthesis (cytoplasmic growth), turgor-driven cell-wall extension, mitotic cycle, and endocycle. Potential feedbacks between these processes include a cell-size checkpoint operating before DNA synthesis and a link between DNA contents and maximum cell size. In addition, key intercellular signals and growth regulatory genes appear to target at the same time cell-cycle and cell-growth functions. For example, auxin, gibberellin, and brassinosteroid all have parallel links to cell-cycle progression (through S-phase Cyclin D-CDK and the anaphase-promoting complex) and cell-wall functions (through cell-wall extensibility or microtubule dynamics). Another intercellular signal mediated by microtubule dynamics is the mechanical stress caused by growth of interconnected cells. Superimposed on developmental controls, sugar signalling through the TOR pathway has recently emerged as a central control point linking cytoplasmic growth, cell-cycle and cell-wall functions. Recent progress in quantitative imaging and computational modelling will facilitate analysis of the multiple interconnections between plant cell growth and cell cycle and ultimately will be required for the predictive manipulation of plant growth.

Intraductal Carcinoma Of The Prostate: Interobserver Reproducibility Survey Of 39 Urologic Pathologists.

The diagnosis of intraductal carcinoma (IDC) of the prostate remains subjective because 3 sets of diagnostic criteria are in use. An internet survey was compiled from 38 photomicrographs showing duct proliferations: 14 signed out as high-grade prostatic intraepithelial neoplasia (HGPIN), 17 IDC, and 7 invasive cribriform/ductal carcinoma. Each image was assessed for the presence of 9 histologic criteria ascribed to IDC. Thirty-nine respondents were asked to rate images as (1) benign/reactive, (2) HGPIN, (3) borderline between HGPIN and IDC, (4) IDC, or (5) invasive cribriform/ductal carcinoma. Intraclass correlation coefficient was 0.68. There was 70% overall agreement with HGPIN, 43% with IDC, and 73% with invasive carcinoma (P < .001, χ(2)). Respondents considered 19 (50%) of 38 cases as IDC candidates, of which 5 (26%) had a two-thirds consensus for IDC; two-thirds consensus for either borderline or IDC was reached in 9 (47%). Two-thirds consensus other than IDC was reached in the remaining 19 of 38 cases, with 15 supporting HGPIN and 4 supporting invasive carcinoma. Findings that differed across diagnostic categories were lumen-spanning neoplastic cells (P < .001), 2× benign duct diameters (P < .001), duct space contours (round, irregular, and branched) (P < .001), papillary growth (P = .048), dense cribriform or solid growth (both P = .023), and comedonecrosis (P = .015). When the 19 of 38 images that attained consensus for HGPIN or invasive carcinoma were removed from consideration, lack of IDC consensus was most often attributable to only loose cribriform growth (5/19), central nuclear maturation (5/19), or comedonecrosis (3/19). Of the 9 histologic criteria, only 1 retained significant correlation with a consensus diagnosis of IDC: the presence of solid areas (P = .038). One case that attained IDC consensus had less than 2× duct enlargement yet still had severe nuclear atypia and nucleomegaly. Six fold nuclear enlargement was not significant (P = .083), although no image had both 6× nuclei and papillary or loose cribriform growth: a combination postulated as sufficient criteria for IDC. Finally, 20.5% of respondents agreed that an isolated diagnosis of IDC on needle biopsy warrants definitive therapy, 20.5% disagreed, and 59.0% considered the decision to depend upon clinicopathologic variables. Although IDC diagnosis remains challenging, we propose these criteria: a lumen-spanning proliferation of neoplastic cells in preexisting ducts with a dense cribriform or partial solid growth pattern. Solid growth, in any part of the duct space, emerges as the most reproducible finding to rule in a diagnosis of IDC. Comedonecrosis is a rarer finding, but in most cases, it should rule in IDC. Duct space enlargement to greater than 2× the diameter of the largest, adjacent benign spaces is usually present in IDC, although there may be rare exceptions.

Icam-1 Expression On Immune Cells In Chronic Villitis.

ICAM-1 expression on the villous syncytiotrophoblast (ST) is believed to participate in migration of maternal cells into the inflamed villi regardless of villitis etiology. However, its expression on immune cells in chronic villitis (CV) has yet to be analyzed. ICAM-1 induces cell-cell adhesion allowing intercellular communication, T cell-mediated defense mechanism, and inflammatory response. 21 cases of CV (all without an identifiable etiologic agent) and 3 control placentas were analyzed using ICAM-1, and for immune cells CD45, CD3 and CD68. These cells were subdivided according to their location in inflamed villi: a) within the inflamed villi and b) outside forming perivillous aggregates. Large amounts of CD45, CD3 and CD68 were found within the inflamed villi and forming perivillous aggregates attached to areas of trophoblastic loss. Inflamed villi usually showed ICAM-1+ ST. The majority of immune cells surrounding areas of trophoblastic rupture presented marked expression of ICAM-1. In contrast, a small number of immune cells within the inflamed villi exhibited ICAM-1 expression. Only some (<5%) inflamed villi without trophoblastic rupture and with ICAM-1+ ST presented adherence of immune cells. In inflamed villi of chronic villitis, the level of ICAM-1 expression on immune cells depends on their location: high in number of cells in the perivillous region and low within the villi. The strongest expression of ICAM-1 on immune cells attached to areas of trophoblastic rupture suggests that the loss of trophoblast can lead to an amplification of the inflammatory response.

Effect Of Particles Of Ashes Produced From Sugarcane Burning On The Respiratory System Of Rats.

The practice of burning sugarcane obtained by non-mechanized harvesting exposes workers and the people of neighboring towns to high concentrations of particulate matter (PM) that is harmful to health, and may trigger a series of cardiorespiratory diseases. The aim of this study was to analyze the chemical composition of the micro-particles coming from sugarcane burning residues and to verify the effects of this micro-particulate matter on lung and tracheal tissues. Micro-particulate matter (PM10) was obtained by dissolving filter paper containing burnt residues in NaCl solution. This material was instilled into the Wistar rats' nostrils. Histological analyses (hematoxylin and eosin - HE) of cardiac, lung and tracheal tissues were performed. Inflammatory mediators were measured in lung tissues by using ELISA. The chemical composition of the particulate material revealed a large quantity of the phthalic acid ester, high concentrations of phenolic compounds, anthracene and polycyclic aromatic hydrocarbons (PAH). Histological analysis showed a reduction in subjacent conjunctive tissue in the trachea, lung inflammation with inflammatory infiltrate formation and reduction of alveolar spaces and a significant increase (p<0.05) in the release of IL-1α, IL-1β, IL-6, and INF-γ in the group treated with PM10 when compared to the control group. We concluded that the burning sugarcane residues release many particles, which have toxic chemical compounds. The micro-particulate matter can induce alterations in the respiratory system.

Pollination Ecology Of Two Species Of Elleanthus (orchidaceae): Novel Mechanisms And Underlying Adaptations To Hummingbird Pollination.

Relationships among floral biology, floral micromorphology and pollinator behaviour in bird-pollinated orchids are important issues to understand the evolution of the huge flower diversity within Orchidaceae. We aimed to investigate floral mechanisms underlying the interaction with pollinators in two hummingbird-pollinated orchids occurring in the Atlantic forest. We assessed floral biology, nectar traits, nectary and column micromorphologies, breeding systems and pollinators. In both species, nectar is secreted by lip calli through spaces between the medial lamellar surfaces of epidermal cells. Such form of floral nectar secretion has not been previously described. Both species present functional protandry and are self-compatible yet pollinator-dependent. Fruit sets in hand-pollination experiments were more than twice those under natural conditions, evidencing pollen limitation. The absence of fruit set in interspecific crosses suggests the existence of post-pollination barriers between these synchronopatric species. In Elleanthus brasiliensis, fruits resulting from cross-pollination and natural conditions were heavier than those resulting from self-pollination, suggesting advantages to cross-pollination. Hummingbirds pollinated both species, which share at least one pollinator species. Species differences in floral morphologies led to distinct pollination mechanisms. In E. brasiliensis, attachment of pollinaria to the hummingbird bill occurs through a lever apparatus formed by an appendage in the column, another novelty to the knowledge of orchids. In E. crinipes, pollinaria attachment occurs by simple contact with the bill during insertion into the flower tube, which fits tightly around the bill. The novelties described here illustrate the overlooked richness in ecology and morphophysiology in Orchidaceae. This article is protected by copyright. All rights reserved.