Distributed Representations of Sentences and Documents

Many machine learning algorithms require the input to be represented as a fixed-length feature vector. When it comes to texts, one of the most common fixed-length features is bag-of-words. Despite their popularity, bag-of-words features have two major weaknesses: they lose the ordering of the words and they also ignore semantics of the words. For example, "powerful," "strong" and "Paris" are equally distant. In this paper, we propose Paragraph Vector, an unsupervised algorithm that learns fixed-length feature representations from variable-length pieces of texts, such as sentences, paragraphs, and documents. Our algorithm represents each document by a dense vector which is trained to predict words in the document. Its construction gives our algorithm the potential to overcome the weaknesses of bag-of-words models. Empirical results show that Paragraph Vectors outperform bag-of-words models as well as other techniques for text representations. Finally, we achieve new state-of-the-art results on several text classification and sentiment analysis tasks

Dynamics and bifurcations in a simple quasispecies model of tumorigenesis

Cancer is a complex disease and thus is complicated to model. However, simple models that describe the main processes involved in tumoral dynamics, e.g., competition and mutation, can give us clues about cancer behaviour, at least qualitatively, also allowing us to make predictions. Here we analyze a simplified quasispecies mathematical model given by differential equations describing the time behaviour of tumor cells populations with different levels of genomic instability. We find the equilibrium points, also characterizing their stability and bifurcations focusing on replication and mutation rates. We identify a transcritical bifurcation at increasing mutation rates of the tumor cells population. Such a bifurcation involves an scenario with dominance of healthy cells and impairment of tumor populations. Finally, we characterize the transient times for this scenario, showing that a slight increase beyond the critical mutation rate may be enough to have a fast response towards the desired state (i.e., low tumor populations) during directed mutagenic therapies

Identification of erythroferrone as an erythroid regulator of iron metabolism.

Recovery from blood loss requires a greatly enhanced supply of iron to support expanded erythropoiesis. After hemorrhage, suppression of the iron-regulatory hormone hepcidin allows increased iron absorption and mobilization from stores. We identified a new hormone, erythroferrone (ERFE), that mediates hepcidin suppression during stress erythropoiesis. ERFE is produced by erythroblasts in response to erythropoietin. ERFE-deficient mice fail to suppress hepcidin rapidly after hemorrhage and exhibit a delay in recovery from blood loss. ERFE expression is greatly increased in Hbb(th3/+) mice with thalassemia intermedia, where it contributes to the suppression of hepcidin and the systemic iron overload characteristic of this disease

Dynamic characterization of cellulose nanofibrils in sheared and extended semi-dilute dispersions

New materials made through controlled assembly of dispersed cellulose nanofibrils (CNF) has the potential to develop into biobased competitors to some of the highest performing materials today. The performance of these new cellulose materials depends on how easily CNF alignment can be controlled with hydrodynamic forces, which are always in competition with a different process driving the system towards isotropy, called rotary diffusion. In this work, we present a flow-stop experiment using polarized optical microscopy (POM) to study the rotary diffusion of CNF dispersions in process relevant flows and concentrations. This is combined with small angle X-ray scattering (SAXS) experiments to analyze the true orientation distribution function (ODF) of the flowing fibrils. It is found that the rotary diffusion process of CNF occurs at multiple time scales, where the fastest scale seems to be dependent on the deformation history of the dispersion before the stop. At the same time, the hypothesis that rotary diffusion is dependent on the initial ODF does not hold as the same distribution can result in different diffusion time scales. The rotary diffusion is found to be faster in flows dominated by shear compared to pure extensional flows. Furthermore, the experimental setup can be used to quickly characterize the dynamic properties of flowing CNF and thus aid in determining the quality of the dispersion and its usability in material processes.Comment: 45 pages, 13 figure

Experimental study of the turbulent structure of a boundary layer developing over a rough surface

National audienceNous avons analysé les caractéristiques turbulentes de la couche limite neutre se développant sur une surface rugueuse. Des expériences ont été réalisées dans un canal hydraulique pour mesurer les champs bidimensionnels de vitesse via la technique de Particle Image Velocimetry (PIV). Ces données expérimentales décrivent cette couche limite en termes de quantités moyennes et turbulentes avec un haut niveau de précision. Les termes des budgets d'énergie ont ainsi pu être estimés. Il apparait que le développement de la couche limite rugueuse ne modifie pas significativement la répartition entre les termes constitutifs des différents bilans. Les échelles de longueurs intégrales ont été estimées, de manière directe, à partir des corrélations spatiales. Ces échelles de longueurs verticales permettent alors de paramétrer les longueurs de mélange et de dissipation, utilisées dans des modèles 1D de prédiction. / We analysed the turbulent characteristics of the neutral boundary-layer developing over rough surfaces. A set of hydraulic flume experiments were carried out in order to measure two-dimensional velocity fields via a particle image velocimetry (PIV) technique. The resulting experimental data describe this boundary layer in terms of the mean and turbulent quantities with a high level of accuracy. These results enabled the terms of the energy budgets to be estimated and show that the development of the rough neutral boundary layer does not significantly modify the repartition between the constitutive terms of the different budget. Spatial correlation analysis permitted the longitudinal and vertical integral length also to be estimated directly. Theses vertical length scales are then used to parametrize the mixing and dissipative lengths, used in 1D prediction models

Flash suppression and flash facilitation in binocular rivalry

We show that previewing one half image of a binocular rivalry pair can cause it to gain initial dominance when the other half is added, a novel phenomenon we term flash facilitation. This is the converse of a known effect called flash suppression, where the previewed image becomes suppressed upon rivalrous presentation. The exact effect of previewing an image depends on both the duration and the contrast of the prior stimulus. Brief, low-contrast prior stimuli facilitate, whereas long, high-contrast ones suppress. These effects have both an eye-based component and a pattern-based component. Our results suggest that, instead of reflecting two unrelated mechanisms, both facilitation and suppression are manifestations of a single process that occurs progressively during presentation of the prior stimulus. The distinction between the two phenomena would then lie in the extent to which the process has developed during prior stimulation. This view is consistent with a neural model previously proposed to account for perceptual stabilization of ambiguous stimuli, suggesting a relation between perceptual stabilization and the present phenomena

Disseminated cryptococcosis in solid organ transplant recipient

Introduction: Invasive fungal diseases (IFD) have an overall incidence of 3.1% in solid organ transplant (SOT) patients.1 Although rare, they result in high mortality, likely due to a delay in treatment caused by inherent delay of fungal culture-based diagnosis.2-5 Cryptococcus are the third most common cause of fungal infection in SOT patients. 6-7 Objective: Here we present a unique case of disseminated cryptococcosis in a patient who underwent kidney transplantation with rapid symptomatic onset and presence of perinephric and perihepatic abscesses. The findings presented may inform clinicians of the potentially unusual manifestations of common fungal infections in solid organ transplant recipients. Methods: This study was submitted and declared except by the local Institutional Review Board (IRB). Pertinent clinical and radiologic information was extracted from the electronic medical record. Results: Patient was found to have leukocytosis, low hematocrit, patchy lung infiltrates, and perinephric and perihepatic abscesses on imaging. Discussion: Unique to this case is the prompt development of disseminated cryptococcal infection 3 months after transplantation; the typical time to onset is typically between 1.5-5 years posttransplantation.1 Additionally perinephric and perihepatic abscesses were unusual findings for this infection.8 Based on the history, it is likely the patient acquired Cryptococcus while engaging in farm-work, resulting in its unique presentation. Also unusual is the central nervous system involvement that developed despite tacrolimus use. This is a finding that contrasts previous literature. 9-10 This patient had multiple risk factors previously described in literature, including prior ICU admission, hemodialysis, corticosteroid and antibiotic use.9-

Diesel Engine Emission Model Transient Cycle Validation

A control intended data driven B-spline model for NOx and soot emitted was developed and validated for the 5-cylinder, 2.4-litre Volvo passenger car diesel engine in earlier work. This work extends on the same methodology with some improvements on the model structure for more intuitive calibration and is also developed for the new generation 4-cylinder, 2- litre Volvo passenger car diesel engine. The earlier model was validated using steady state engine measurements and proposed that the model would hold good for transient engine operation. The hypothesis formulated is that a transient engine emission model can be envisioned as a sequence of multi-step steady state engine operation points with minor deviations from the nominal engine operating conditions. The theory is supported by the literature that provides more insight into the transient operation. This idea is carried out in the current work using engine test cell measurements validated for a NEDC as well as a normal road drive cycle that depicts a more transient driving behaviour in comparison to the standard emission driving cycles. Nearly 4600 engine operating points with steady state measurement including nominal and deviant conditions have been used in the development of the model. The ability of the data driven approach to mimic the engine emission generation characteristics during the engine transient operation is analysed and its superior performance in comparison to the Nominal model and the Regression model is demonstrated