113 research outputs found

    An hybrid Approach for the Computation of Guided Modes in Integrated Optics

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    In this work, we are interested in the numerical approximation of an eigenvalu- e problem posed in \Rd arising from the computation of guided modes in integrated optics waveguides, which are particular cases of open waveguides- . We consider a stratified waveguide translationally invariant in the infinite propagation direction. Its cross-section is also supposed to be an unbounded and stratified medium where an appropiate perturbation of the refraction index has been introduced to ensure the existence of guided modes. Under the weak guiding assumption, a method to compute the guided modes has been proposed and analyzed in [11]. This method appears as a combination of analytical methods which take into account the unbounded and stratified character of the propagation medium and numerical computations which can be reduced to a neighborhood of the perturbation. In this paper, we are concerned with the numerical implementation of the method and we present some numerical results

    Implicit body representations and the conscious body image

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    Recent studies have revealed that somatosensory processing relies on a class of implicit body representations showing large distortions of size and shape. The relation between these representations and the conscious body image remains unclear. Dissociations have been reported in the clinical literature on eating disorders between different body image measures, with larger and more consistent distortions found with depictive measures, in which participants compare their body to a visual depiction of a body, than metric measures, in which participants compare their body to some non-body standard. Here, we compared implicit body representations underlying position sense to the body image measured with both depictive and metric methods. The body image was measured using both a depictive method (template matching) in which participants judged whether their hand was wider or more slender than a shown hand picture, and a metric method (line length) in which participants judged whether different parts of the their hand were shorter or longer than a presented line. Consistent with previous findings, characteristic distortions were found for the implicit body representation underlying position sense. These distortions were also found in attenuated form for metric – but not depictive – body image measures. While replicating the basic dissociation between implicit body representations and the conscious body image, these results demonstrate that this dissociation is not absolute and specific tasks may utilise both to varying degrees depending on task demands. Metric measures may not be pure measures of body image, but some combination of visual and somatosensory body representations

    Functional changes in the cortical semantic network in amnestic mild cognitive impairment

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    Semantic memory impairment has been documented in older individuals with amnestic Mild cognitive impairment (aMCI), who are at risk of developing Alzheimer’s disease (AD), yet little is known about the neural basis of this breakdown. The main objective of this study was to investigate the brain mechanisms associated with semantic performance in patients with aMCI. Method: A group of aMCI patients and a group of healthy older controls carried out a semantic categorization task while their brain activity was recorded using magnetoencephalography (MEG). During the task, participants were shown famous faces and had to determine whether each famous person matched a given occupation. The main hypotheses were that: (i) semantic processing should be compromised for aMCI patients, and (ii) these deficits should be associated with cortical dysfunctions within specific areas of the semantic network. Results: Behavioural results showed that aMCI participants were significantly slower and less accurate than control participants at the semantic task, corroborating previous reports. Additionally, relative to controls, a significant pattern of hyperactivation was found in the aMCI group within specific regions of the semantic network, including the right anterior temporal lobe and inferior prefrontal cortex. Conclusions: Abnormal functional activation within key areas of the semantic network suggests that it is compromised early in the disease process. Moreover, this pattern of increased activation in aMCI was positively associated with grey matter integrity in specific areas, but was not associated with any specific pattern of atrophy, suggesting that functional hyperactivation may precede atrophy of the semantic network in aMCI

    Sistema inspectivo de trabajo y la informalidad laboral en San Martín. A propósito de una revisión documental

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    Labor informality is a problem that persists over time and has not been reduced in almost all Latin American countries; Thus, it was evaluated whether the public-private articulation is related to the labor inspection system in micro-enterprises, so that it can be determined if the interrelation of the public entity with the private one constitutes a fundamental element to reduce labor informality. At the same time, it is analyzed whether the inspection system is really effective in the San Martín region and whether good public management is being developed by this entity; and, finally, a program of good work practices in micro-enterprises is proposed in SUNAFIL San Martín. The final conclusion is that there is a significant influence of the public-private articulation with the Inspecting System of Work in micro-enterprises in SUNAFIL San Martín; This is because, if SUNAFIL works together with the business sector, it will reduce labor informality in the region, since, in exchange, these companies will be able to obtain certain labor benefits that will help them be more competitive in the market. and therefore will avoid labor sanctions.La informalidad laboral es un problema que persiste a través del tiempo y que no se ha logrado reducir en casi todos los países de Latinoamérica; es así que, se evaluó si la articulación público-privado tiene relación con el sistema inspectivo laboral en microempresas, esto, con el fin de determinar si la interrelación del ente público con el privado constituye un elemento fundamental para disminuir la informalidad laboral. A su vez, se analiza si el sistema inspectivo es realmente eficaz en la región San Martín y si a la vez, se está desarrollando una buena gestión pública por parte de esta entidad. Finalmente se propone un programa de buenas prácticas labores en microempresas en SUNAFIL San Martín. La conclusión final es que existe una influencia significativa de la articulación público-privado, entre el Sistema Inspectivo de Trabajo y las microempresas, debido a que, si la SUNAFIL trabaja de manera conjunta con el sector empresarial, logrará que la informalidad laboral se reduzca en la región, dado que, a cambio, estas empresas podrán obtener beneficios laborales que les permitirán ser más competitivas en el mercado, evitando además sanciones administrativas

    Quantification of recirculation as an adjuvant to transthoracic echocardiography for optimization of dual-lumen extracorporeal life support

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    Proper cannula positioning in single site veno-venous extracorporeal life support (vv-ELS) is cumbersome and necessitates image guidance to obtain a safe and stable position within the heart and the caval veins. Importantly, image-guided cannula positioning alone is not sufficient, as possible recirculation cannot be quantified. We present an ultrasound dilution technique allowing quantification of recirculation for optimizing vv-ELS. We suggest quantification of recirculation in addition to image guidance to provide optimal vv-ELS

    Maerl grounds : habitats of high biodiversity in European seas

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    The BIOMAERL programme is a 3-year collaborative programme between laboratories in UK, Spain, France and Malta which began in February 1996. Its main plans are described in the workplan. A full inventory of the biological composition (biodiversity) of maerl bed assemblages in these regions therefore has yet to be completed, but progress is outlined below.peer-reviewe

    The role of the right temporoparietal junction in perceptual conflict: detection or resolution?

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    The right temporoparietal junction (rTPJ) is a polysensory cortical area that plays a key role in perception and awareness. Neuroimaging evidence shows activation of rTPJ in intersensory and sensorimotor conflict situations, but it remains unclear whether this activity reflects detection or resolution of such conflicts. To address this question, we manipulated the relationship between touch and vision using the so-called mirror-box illusion. Participants' hands lay on either side of a mirror, which occluded their left hand and reflected their right hand, but created the illusion that they were looking directly at their left hand. The experimenter simultaneously touched either the middle (D3) or the ring finger (D4) of each hand. Participants judged, which finger was touched on their occluded left hand. The visual stimulus corresponding to the touch on the right hand was therefore either congruent (same finger as touch) or incongruent (different finger from touch) with the task-relevant touch on the left hand. Single-pulse transcranial magnetic stimulation (TMS) was delivered to the rTPJ immediately after touch. Accuracy in localizing the left touch was worse for D4 than for D3, particularly when visual stimulation was incongruent. However, following TMS, accuracy improved selectively for D4 in incongruent trials, suggesting that the effects of the conflicting visual information were reduced. These findings suggest a role of rTPJ in detecting, rather than resolving, intersensory conflict

    Impact Earth: A review of the terrestrial impact record

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    Over the past few decades, it has become increasingly clear that the impact of interplanetary bodies on other planetary bodies is one of the most ubiquitous and important geological processes in the Solar System. This impact process has played a fundamental role throughout the history of the Earth and other planetary bodies, resulting in both destructive and beneficial effects. The impact cratering record of Earth is critical to our understanding of the processes, products, and effects of impact events. In this contribution, we provide an up-to-date review and synthesis of the impact cratering record on Earth. Following a brief history of the Impact Earth Database (available online at http://www.impactearth.com), the definition of the main categories of impact features listed in the database, and an overview of the impact cratering process, we review and summarize the required evidence to confirm impact events. Based on these definitions and criteria, we list 188 hypervelocity impact craters and 13 impact craters (i.e., impact sites lacking evidence for shock metamorphism). For each crater, we provide details on key attributes, such as location, date confirmed, erosional level, age, target properties, diameter, and an overview of the shock metamorphic effects and impactites that have been described in the literature. We also list a large number of impact deposits, which we have classified into four main categories: tektites, spherule layers, occurrences of other types of glass, and breccias. We discuss the challenges of recognizing and confirming impact events and highlight weaknesses, contradictions, and inconsistencies in the literature. We then address the morphology and morphometry of hypervelocity impact craters. Based on the Impact Earth Database, it is apparent that the transition diameter from simple to complex craters for craters developed in sedimentary versus crystalline target rocks is less pronounced than previously reported, at approximately 3 km for both. Our analysis also yields an estimate for stratigraphic uplift of 0.0945D0.6862, which is lower than previous estimates. We ascribe this to more accurate diameter estimates plus the variable effects of erosion. It is also clear that central topographic peaks in terrestrial complex impact craters are, in general, more subdued than their lunar counterparts. Furthermore, a number of relatively well-preserved terrestrial complex impact structures lack central peaks entirely. The final section of this review provides an overview of impactites preserved in terrestrial hypervelocity impact craters. While approximately three quarters of hypervelocity impact craters on Earth preserve some portion of their crater-fill impactites, ejecta deposits are known from less than 10%. In summary, the Impact Earth Database provides an important new resource for researchers interested in impact craters and the impact cratering process and we welcome input from the community to ensure that the Impact Earth website (http://www.impactearth.com) is a living resource that is as accurate and as up-to-date, as possible

    The Canadian Open Neuroscience Platform—An open science framework for the neuroscience community

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    ABSTRACT: The Canadian Open Neuroscience Platform (CONP) takes a multifaceted approach to enabling open neuroscience, aiming to make research, data, and tools accessible to everyone, with the ultimate objective of accelerating discovery. Its core infrastructure is the CONP Portal, a repository with a decentralized design, where datasets and analysis tools across disparate platforms can be browsed, searched, accessed, and shared in accordance with FAIR principles. Another key piece of CONP infrastructure is NeuroLibre, a preprint server capable of creating and hosting executable and fully reproducible scientific publications that embed text, figures, and code. As part of its holistic approach, the CONP has also constructed frameworks and guidance for ethics and data governance, provided support and developed resources to help train the next generation of neuroscientists, and has fostered and grown an engaged community through outreach and communications. In this manuscript, we provide a high-level overview of this multipronged platform and its vision of lowering the barriers to the practice of open neuroscience and yielding the associated benefits for both individual researchers and the wider community

    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years
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