Miracle-dz/UniFAR-FTUs huggingface dataset:
Detection of mesial temporal lobe hypoperfusion in patients with temporal lobe epilepsy by use of arterial spin labeled perfusion MR imaging.

BACKGROUND AND PURPOSE Interictal hypometabolism has lateralizing value in cases of temporal lobe epilepsy and positive predictive value for seizure-free outcome after surgery to treat epilepsy. Alterations in regional cerebral metabolism can also be inferred from measurements of regional cerebral perfusion. The purpose of this study was to determine the feasibility of detecting cerebral blood flow (CBF) asymmetries in the mesial temporal lobes using continuous arterial spin labeling perfusion MR imaging, which is a noninvasive method for calculating regional CBF. METHODS Twelve patients with medically refractory temporal lobe epilepsy who underwent preoperative evaluation for temporal lobectomy and 12 normal control participants were studied retrospectively. Absolute and normalized mesial temporal CBF measurements were compared between the patient and control groups. Lateralization based on a perfusion asymmetry index was compared with metabolic ((18)[F]-fluorodeoxyglucose positron emission tomography) and hippocampal volumetric asymmetry indices and with clinical lateralization. RESULTS Mesial temporal CBF was more asymmetric in patients with temporal lobe epilepsy than in normal control participants, although asymmetric mesial temporal CBF was also found in normal participants, with the left side dominant. Ipsilateral mesial temporal CBF was significantly decreased compared with contralateral mesial temporal CBF in patients with temporal lobe epilepsy. Global CBF measurements were significantly decreased in patients compared with control participants. Asymmetry in mesial temporal blood flow in patients persisted after normalization to global CBF. Lateralization using continuous arterial spin labeling perfusion MR imaging asymmetry index significantly correlated with lateralization based on (18)[F]-fluorodeoxyglucose positron emission tomography hypometabolism, hippocampal volumes, and clinical evaluation. CONCLUSION Continuous arterial spin labeling perfusion MR imaging can detect interictal asymmetries in mesial temporal lobe perfusion in patients with temporal lobe epilepsy. This technique is readily combined with routine structural assessment and potentially offers an inexpensive and noninvasive means of screening for asymmetries in interictal mesial temporal lobe function.
Can market-clearing models explain U.S. labor market fluctuations?

Throughout the past two decades, market-clearing models of the business cycle have been praised for their ability to explain key empirical features of the post-war U.S. business cycle. Real business cycle (RBC) theory shows that in a model grounded in microeconomic foundations, disturbances to national productivity can explain how aggregate variables such as GDP, consumption and investment behave over time, relative to each other. One of the primary weaknesses of the standard RBC model, however, is its inability to account for some important aspects of U.S. labor market fluctuations. In this article, Victor E. Li summarizes important U.S. business cycle facts and examines how and why these market-clearing models have so much difficulty explaining the mannner in which these facts pertain to the labor market. Li then develops a simple market-clearing framework that demonstrates how a more realistic treatment of unemployment and incomplete risk-sharing may provide an alternative approach to better account for these labor market facts. In particular, Li looks at the situation where the risk of being unemployed cannot be completely shared across all individuals when there are unexpected aggregate economic shocks.
Sparse Sums of Positive Semidefinite Matrices

Many fast graph algorithms begin by preprocessing the graph to improve its sparsity. A common form of this is spectral sparsification, which involves removing and reweighting the edges of the graph while approximately preserving its spectral properties. This task has a more general linear algebraic formulation in terms of approximating sums of rank-one matrices. This article considers a more general task of approximating sums of symmetric, positive semidefinite matrices of arbitrary rank. We present two deterministic, polynomial time algorithms for solving this problem. The first algorithm applies the pessimistic estimators of Wigderson and Xiao, and the second involves an extension of the method of Batson, Spielman, and Srivastava. These algorithms have several applications, including sparsifiers of hypergraphs, sparse solutions to semidefinite programs, sparsifiers of unique games, and graph sparsifiers with various auxiliary constraints.
Regulation of Streptococcus pneumoniae clp Genes and Their Role in Competence Development and Stress Survival

ABSTRACT In vitro mariner transposon mutagenesis ofStreptococcus pneumoniae chromosomal DNA was used to isolate regulatory mutants affecting expression of thecomCDE operon, encoding the peptide quorum-sensing two-component signal transduction system controlling competence development. A transposon insertion leading to increasedcomC expression was found to lie directly upstream from the S. pneumoniae clpP gene, encoding the proteolytic subunit of the Clp ATP-dependent protease, whose expression inBacillus subtilis is controlled by the CtsR repressor. In order to examine clp gene regulation in S. pneumoniae, a detailed analysis of the complete genome sequence was performed, indicating that there are five likely CtsR-binding sites located upstream from the clpE, clpP, andclpL genes and thectsR-clpC and groESLoperons. The S. pneumoniae ctsR gene was cloned under the control of an inducible promoter and used to demonstrate regulation of the S. pneumoniae clpP and clpE genes and the clpC and groESL operons by usingB. subtilis as a heterologous host. The CtsR protein ofS. pneumoniae was purified and shown to bind specifically to the clpP, clpC, clpE, andgroESL regulatory regions. S. pneumoniaeΔctsR, ΔclpP, ΔclpC, and ΔclpE mutants were constructed by gene deletion/replacement. ClpP was shown to act as a negative regulator, preventing competence gene expression under inappropriate conditions. Phenotypic analyses also indicated that ClpP and ClpE are both required for thermotolerance. Contrary to a previous report, we found that ClpC does not play a major role in competence development, autolysis, pneumolysin production, or growth at high temperature of S. pneumoniae.
Segmentation of Musical Signals Using Hidden Markov Models.

In this paper, we present a segmentation algorithm for acoustic musical signals, using a hidden Markov model. Through unsupervised learning, we discover regions in the music that present steady statistical properties: textures. We investigate different front-ends for the system, and compare their performances. We then show that the obtained segmentation often translates a structure explained by musicology: chorus and verse, different instrumental sections, etc. Finally, we discuss the necessity of the HMM and conclude that an efficient segmentation of music is more than a static clustering and should make use of the dynamics of the data.
Thermal Conductivity of Water/Carbon Nanotube Composite Systems: Insights From Molecular Dynamics Simulations

The effective thermal conductivity of water/carbon nanotube (CNT) composite systems is predicted using molecular dynamics simulation. Both empty and water-filled CNTs with diameters ranging from 0.83 nm to 1.26 nm are considered. Using a direct application of the Fourier law, we explore the transition to diffusive phonon transport with increasing CNT length and identify the correlation between CNT diameter and fully-diffusive thermal conductivity. Using Green-Kubo linear response theory, we explore how the thermal conductivity of water inside CNT varies with tube diameter. We predict the effective thermal conductivity of the composite systems and examine how the phonon modes in the CNT are affected by interactions with the water molecules. © 2009 ASME
Gouvernance de réseaux interorganisationnels : cas d'un réseau d'organisations sociales et collectives

En realisant une etude longitudinale en profondeur d'un cas de reseaux d'organisations sociales et collectives, le Reseau de la finance solidaire et responsable au Quebec (Reseau FSRQ), notre these explique l'evolution de la gouvernance de reseaux interorganisationnels (RIO), son passage d'un mode informel a formel. En plus d'identifier les mecanismes relies a ces deux modes de gouvernance, montrer la complementarite et la linearite entre eux, et reveler l'importance des mecanismes informels pour la formalisation de RIO, notre etude montre, en mobilisant le neoinstitutionnalisme sociologique (particulierement le concept du travail institutionnel), le role des pratiques de creation institutionnelle (normatives, cognitives et politiques) que developpent les membres du Reseau FSRQ, comme collectif institutionnel, dans la dynamique de sa gouvernance. L'etude revele egalement que ces pratiques d'institutionnalisation s'entrelacent et se tricotent, et sont reliees aux etapes de developpement de ce reseau. Plus encore, notre etude explique comment des acteurs aux logiques differentes ont travaille ensemble pour formaliser et construire la gouvernance de leur reseau, et ce, dans une visee de creer un nouveau champ institutionnel, celui de la finance solidaire et responsable. Pour y arriver, ils ont collectivement developpe plusieurs pratiques institutionnelles. L'etude revele donc que la gouvernance de RIO est une construction collective menee par un collectif d'acteurs qu'on peut qualifier « d'entrepreneur institutionnel collectif et solidaire ». Cet entrepreneur a mis en place sa gouvernance interne et vise construire son champ institutionnel afin d'influencer le systeme financier conventionnel. Avec ces resultats, cette these apporte des contributions theoriques a son champ d'etude en emergence, celui de la gouvernance et de la dynamique de RIO. Elle contribue egalement a la theorie neoinstitutionnelle sociologique qu'elle mobilise en proposant le concept de l'« entrepreneur institutionnel collectif et solidaire » et en revelant de nouvelles pratiques pour le concept de travail institutionnel. Enfin, en proposant certaines pistes methodologiques qui pourraient etre utiles pour les chercheurs qui etudient les RIO, elle participe a l'avancement de la recherche sur ces objets d'etude complexes. Sur le plan pratique, cette these propose egalement des resultats interessants ; elle revele des pratiques de gouvernance qui peuvent inspirer les gestionnaires et animateurs de RIO, particulierement ceux des reseaux d'organisations collectives et sociales. ______________________________________________________________________________ MOTS-CLES DE L’AUTEUR : reseaux interorganisationnels, gouvernance de reseaux, formalisation de reseaux, reseau d'organisations sociales et collectives, pratiques institutionnelles, neoinstitutionnalisme sociologique.
A fixation method to preserve cultured cell cytonemes facilitates mechanistic interrogation of morphogen transport

During development, extracellular cues guiding cell fate determination are provided by morphogens. One mechanism by which morphogens are proposed to traverse extracellular space is by traveling along specialized filopodia called cytonemes. These cellular highways extend between signal-producing and -receiving cells to enable direct morphogen delivery. Although genetic studies support cytoneme involvement in morphogen transport, mechanistic insight into how they are regulated is limited owing to technical challenges associated with performing cell biological analysis of the delicate filopodial structures. Here, we introduce a fixation method whereby cultured cell cytonemes can be preserved for imaging studies, allowing investigation of cytoneme regulation using standard cell biological techniques. Using this method, we examined Hedgehog-containing cytonemes and identified a role for the Hedgehog deployment protein Dispatched in cytoneme stabilization. We demonstrate that Hedgehog and Dispatched colocalize in cytonemes, and that cholesterol-modified Hedgehog acts through Dispatched to increase cytoneme occurrence. Live imaging suggests that this occurs through Dispatched-mediated slowing of cytoneme retraction rates. Dispatched-induced cytoneme modulation was recapitulated in wing imaginal discs of transgenic Drosophila, providing evidence that cultured cell cytoneme analysis is predictive of in vivo functionality. Summary: A new fixation method for preserving cultured cell cytonemes, used in combination with live cell imaging, reveals that the Hedgehog deployment protein Dispatched promotes cytoneme occurrence by slowing retraction rates.
Modeling the Role of Peroxisome Proliferator-Activated Receptor γ and MicroRNA-146 in Mucosal Immune Responses to Clostridium difficile

Clostridium difficile is an anaerobic bacterium that has re-emerged as a facultative pathogen and can cause nosocomial diarrhea, colitis or even death. Peroxisome proliferator-activated receptor (PPAR) γ has been implicated in the prevention of inflammation in autoimmune and infectious diseases; however, its role in the immunoregulatory mechanisms modulating host responses to C. difficile and its toxins remains largely unknown. To characterize the role of PPARγ in C. difficile-associated disease (CDAD), immunity and gut pathology, we used a mouse model of C. difficile infection in wild-type and T cell-specific PPARγ null mice. The loss of PPARγ in T cells increased disease activity and colonic inflammatory lesions following C. difficile infection. Colonic expression of IL-17 was upregulated and IL-10 downregulated in colons of T cell-specific PPARγ null mice. Also, both the loss of PPARγ in T cells and C. difficile infection favored Th17 responses in spleen and colonic lamina propria of mice with CDAD. MicroRNA (miRNA)-sequencing analysis and RT-PCR validation indicated that miR-146b was significantly overexpressed and nuclear receptor co-activator 4 (NCOA4) suppressed in colons of C. difficile-infected mice. We next developed a computational model that predicts the upregulation of miR-146b, downregulation of the PPARγ co-activator NCOA4, and PPARγ, leading to upregulation of IL-17. Oral treatment of C. difficile-infected mice with the PPARγ agonist pioglitazone ameliorated colitis and suppressed pro-inflammatory gene expression. In conclusion, our data indicates that miRNA-146b and PPARγ activation may be implicated in the regulation of Th17 responses and colitis in C. difficile-infected mice.
Segmentation of Degraded Malayalam Words: Methods and Evaluation

In most of the Optical Character Recognition softwares, a substantial percentage of errors are caused by the incorrect segmentation of degraded words. This is especially true for recognizing old books, newspapers and historical manuscripts. In this paper, we propose multiple segmentation methods which address the problem of cuts and merges in degraded words. We have created an annotated dataset of 1034 word images with pixel level ground truth for quantitative evaluation of the methods. We compare the methods with a baseline implementation based on connected component analysis. We report substantial improvement in accuracy both at character and at word level.
Overexpression of the Large-Conductance, Ca2+-Activated K+ (BK) Channel Shortens Action Potential Duration in HL-1 Cardiomyocytes

Hereditary long‐QT syndrome (LQTS) is caused by mutations in ion channel genes resulting in a prolonged action potential duration (APD) in cardiomyocytes. Complications include syncope and sudden cardiac death. Large‐conductance, Ca2+‐activated K+ (BK) channels mediate repolarization of many cell types, but they are not expressed in the plasma membrane of cardiomyocytes. We hypothesized that introduction of BK channels may shorten APD in cardiomyocytes as a potential therapy for LQTS. HL‐1 atrial myocytes were transiently transfected with BK plasmids bicistronically expressing hBK and mCherry or control plasmids expressing only mCherry. Expression of the hBK transgene was confirmed by Western blot, immunocytochemistry and by detecting iberiotoxin (Ibtx)‐sensitive BK current in patch‐clamped cells. Western blots showed that the expression of other ion channels including KV4.3, KV7.1, NaV1.5, and CaV1.2 did not significantly change after BK transfection, whereas KV11.1 was down‐regulated by 20% (n=5). APD at 50% repolarization was 3.7±0.5 ms in BK‐transfected cells compared to 6.3±0.6 ms in control‐transfected cells. Ibtx (100 nmol/L) restored the shortened APD in hBK‐transfected cells to 7.9±1.5 ms (n=5–14). Thus, BK channels can exert a powerful repolarizing influence in HL‐1 myocytes, and may be a useful therapy to reverse LQTS. AHA SDG 0830060N (SWR) and NIH R01HL093526 (NJR)
Eternal Present of the Spotless Mind - Youth, Memory and Participatory Media

The paper’s aim is to explore, through an empirical, qualitative research (focus groups conducted in Turin with preadolescents, adolescents and university students) if web 2.0 can constitute a suitable environment for discussing, sharing and elaborating historical public events and contemporary issues. The research states that web 2.0 is not really decisive for sharing practices related to memory. Web 2.0 is rather a place where people can talk about everyday lives. Most important are, instead, the traditional off line agencies, such as family and peer group.From the point of view of young people interviewed, media elaborate and give relevance to events that should not have so much relevance. Young people's memory though, doesn't have any specific features – it's not specialized; it seems to be aligned to the global and mediatized representation of a recent past.
Making Sensor Networks Immortal: An Energy-Renewal Approach With Wireless Power Transfer

Wireless sensor networks are constrained by limited battery energy. Thus, finite network lifetime is widely regarded as a fundamental performance bottleneck. Recent breakthrough in the area of wireless power transfer offers the potential of removing this performance bottleneck, i.e., allowing a sensor network to remain operational forever. In this paper, we investigate the operation of a sensor network under this new enabling energy transfer technology. We consider the scenario of a mobile charging vehicle periodically traveling inside the sensor network and charging each sensor node's battery wirelessly. We introduce the concept of renewable energy cycle and offer both necessary and sufficient conditions. We study an optimization problem, with the objective of maximizing the ratio of the wireless charging vehicle (WCV)'s vacation time over the cycle time. For this problem, we prove that the optimal traveling path for the WCV is the shortest Hamiltonian cycle and provide a number of important properties. Subsequently, we develop a near-optimal solution by a piecewise linear approximation technique and prove its performance guarantee.
Engine On/Off Control for the Energy Management of a Serial Hybrid Electric Bus via Convex Optimization

Convex optimization has recently been suggested for solving the optimal energy management problem of hybrid electric vehicles. Compared with dynamic programming, this approach can significantly reduce the computational time, but the price to pay is additional model approximations and heuristics for discrete decision variables such as engine on/off control. In this paper, the globally optimal engine on/off conditions are derived analytically. It is demonstrated that the optimal engine on/off strategy is to switch the engine on if and only if the requested power exceeds a certain nonconstant threshold. By iteratively computing the threshold and the power split using convex optimization, the optimal solution to the energy management problem is found. The effectiveness of the presented approach is demonstrated in two sizing case studies. The first case study deals with high-energy-capacity batteries, whereas the second case study deals with supercapacitors that have much lower energy capacity. In both cases, the proposed algorithm yields optimal results much faster than the dynamic programming algorithm.
Wavelet Model-based Stereo for Fast, Robust Face Reconstruction

When reconstructing a specific type or class of object using stereo, we can leverage prior knowledge of the shape of that type of object. A popular class of object to reconstruct is the human face. In this paper we learn a statistical wavelet prior of the shape of the human face and use it to constrain stereo reconstruction within a Bayesian framework. We initialize our algorithm with a, typically noisy, point cloud from a standard stereo algorithm, and search our parameter space for the shape that best fits the point cloud. Due to the wavelet basis, our shape parameters can be optimized independently, thus simplifying and accelerating the search. We follow this by optimizing for a secondary prior and observation: smoothing and photo consistency. Our method is fast, and is robust to noise and outliers. Additionally, we obtain a shape in an parameterized and corresponded shape space, making it ready for further processing such as tracking, recognition or statistical analysis.
Evaluating the reliability of point estimates of wetland reference evaporation

Abstract. The Penman-Monteith formulation of evaporation has been criticised for its reliance upon point estimates so that areal estimates of wetland evaporation based upon single weather stations may be misleading. Typically, wetlands comprise a complex mosaic of land cover types from each of which evaporative rates may differ. The need to account for wetland patches when monitoring hydrological fluxes has been noted. This paper presents work carried out over a wet grassland in Southern England. The significance of fetch on actual evaporation was examined using the approach adopted by Gash (1986) based upon surface roughness to estimate the fraction of evaporation sensed from a specified distance upwind of the monitoring station. This theoretical analysis (assuming near-neutral conditions) reveals that the fraction of evaporation contributed by the surrounding area increases steadily to a value of 77% at a distance of 224 m and thereafter declines rapidly. Thus, point climate observations may not reflect surface conditions at greater distances. This result was tested through the deployment of four weather stations on the wetland. The resultant data suggested that homogeneous conditions prevailed so that the central weather station provided reliable areal estimates of reference evaporation during the observation period March–April 1999. This may be a result of not accounting for high wind speeds and roughness found in wetlands that lead to widespread atmospheric mixing. It should be noted this analysis was based upon data collected during the period March-April when wind direction was constant (westerly) and the land surface was moist. There could be more variation at other times of the year that would lead to greater heterogeneity in actual evaporation. Keywords: evaporation, Penman-Monteith, automatic weather station, fetch, wetland