436 research outputs found

    Reconstruction of eye movements during blinks

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    In eye movement research in reading, the amount of data plays a crucial role for the validation of results. A methodological problem for the analysis of the eye movement in reading are blinks, when readers close their eyes. Blinking rate increases with increasing reading time, resulting in high data losses, especially for older adults or reading impaired subjects. We present a method, based on the symbolic sequence dynamics of the eye movements, that reconstructs the horizontal position of the eyes while the reader blinks. The method makes use of an observed fact that the movements of the eyes before closing or after opening contain information about the eyes movements during blinks. Test results indicate that our reconstruction method is superior to methods that use simpler interpolation approaches. In addition, analyses of the reconstructed data show no significant deviation from the usual behavior observed in readers

    Self-Supervised Learning for Cardiac MR Image Segmentation by Anatomical Position Prediction

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    In the recent years, convolutional neural networks have transformed the field of medical image analysis due to their capacity to learn discriminative image features for a variety of classification and regression tasks. However, successfully learning these features requires a large amount of manually annotated data, which is expensive to acquire and limited by the available resources of expert image analysts. Therefore, unsupervised, weakly-supervised and self-supervised feature learning techniques receive a lot of attention, which aim to utilise the vast amount of available data, while at the same time avoid or substantially reduce the effort of manual annotation. In this paper, we propose a novel way for training a cardiac MR image segmentation network, in which features are learnt in a self-supervised manner by predicting anatomical positions. The anatomical positions serve as a supervisory signal and do not require extra manual annotation. We demonstrate that this seemingly simple task provides a strong signal for feature learning and with self-supervised learning, we achieve a high segmentation accuracy that is better than or comparable to a U-net trained from scratch, especially at a small data setting. When only five annotated subjects are available, the proposed method improves the mean Dice metric from 0.811 to 0.852 for short-axis image segmentation, compared to the baseline U-net

    Second Generation Toolset for Calculation of Induced Seismicity Risk Profiles

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    Localization of a 64-kDa phosphoprotein in the lumen between the outer and inner envelopes of pea chloroplasts

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    The identification and localization of a marker protein for the intermembrane space between the outer and inner chloroplast envelopes is described. This 64-kDa protein is very rapidly labeled by [γ-32P]ATP at very low (30 nM) ATP concentrations and the phosphoryl group exhibits a high turnover rate. It was possible to establish the presence of the 64-kDa protein in this plastid compartment by using different chloroplast envelope separation and isolation techniques. In addition comparison of labeling kinetics by intact and hypotonically lysed pea chloroplasts support the localization of the 64-kDa protein in the intermembrane space. The 64-kDa protein was present and could be labeled in mixed envelope membranes isolated from hypotonically lysed plastids. Mixed envelope membranes incorporated high amounts of 32P from [γ-32P]ATP into the 64-kDa protein, whereas separated outer and inner envelope membranes did not show significant phosphorylation of this protein. Water/Triton X-114 phase partitioning demonstrated that the 64-kDa protein is a hydrophilic polypeptide. These findings suggest that the 64-kDa protein is a soluble protein trapped in the space between the inner and outer envelope membranes. After sonication of mixed envelope membranes, the 64-kDa protein was no longer present in the membrane fraction, but could be found in the supernatant after a 110000 × g centrifugation

    Adenylate effects on protein phosphorylation in the interenvelope lumen of pea chloroplasts

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    A 64-kilodalton (kDa) protein, situated in the lumen between the inner and outer envelopes of pea (Pisum sativum L.) chloroplasts (Soll and Bennett 1988, Eur. J. Biochem., 175, 301–307) is shown to undergo reversible phosphorylation in isolated mixed envelope vesicles. It is the most conspicuously labelled protein after incubation of envelopes with 33 nmol·1-1 [-32P]ATP whereas incubation with 50 mol·1-1 [-32P]ATP labels most prominently two outer envelope proteins (86 and 23 kDa). Half-maximum velocity for phosphorylation of the 64-kDa protein occurs with 200 nmol·1-1 ATP, and around 40 mol·1-1 ATP for phosphorylation of the 86- and 23-kDa proteins, indicating the operation of two distinct kinases. GGuanosine-, uridine-, cytidine 5-triphosphate and AMP are poor inhibitors of the labelling of the 64-kDa protein with [-32P]ATP. On the other hand, ADP has a potent influence on the extent of labelling (half-maximal inhibition at 1–5 mol·1-1). The ADP-dependent appearance of 32P in ATP indicates that ADP acts by reversal of kinase activity and not as a competitive inhibitor. However, the most rapid loss of 32P from pre-labelled 64-kDa protein occurs when envelope vesicles are incubated with ATP t1/2=15 s at 20 molsd1-1 ATP). This induced turnover of phosphate appears to be responsible for the rapid phosphoryl turnover seen in situ

    Variation in Treatment for Trapeziometacarpal Arthrosis

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    Background: Treatment recommendations for trapeziometacarpal (TMC) arthrosis are highly variable from surgeon to surgeon. This study addressed the influence of viewing radiographs on a decision to offer surgery for TMC arthrosis. Methods: In an online survey, 92 hand surgeons viewed clinical scenarios and were asked if they would offer surgery to 30 patients with TMC arthrosis. Forty-two observers were randomly assigned to review clinical information alone and 50 to review clinical information as well as radiographs. The degree of limitation of daily activities, time since diagnosis, prior treatment, pain with grind, crepitation with grind, and metacarpal adduction with metacarpophalangeal hyperextension were randomized for each patient scenario to determine the influence of these factors on offers of surgery. A cross-classified binary logistic multilevel regression analysis identified factors associated with surgeon offer of surgery. Results: Surgeons were more likely to offer surgery when they viewed radiographs (42% vs. 32%, P = 0.01). Other factors associated variation in offer of surgery included greater limitation of daily activities, symptoms for a year, prior splint or injection, deformity of the metacarpophalangeal joint. Factors not associated included limb dominance, prominence of the TMC joint, crepitation with the grind test, and pinch and grip strength. Conclusion: Surgeons that view radiographs are more likely to offer surgery to people with TMC arthrosis. Surgeons are also more likely to offer surgery when people do not adapt with time and nonoperative treatment. Given the notable influence of surgeon bias, and the potential for surgeon and patient impatience with the adaptation process, methods for increasing patient participation in the decision-making process merit additional attention and study

    Spatial representation of corticofugal input in the inferior colliculus: a multicontact silicon probe approach

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    The inferior colliculus (IC) is a well-established target of descending projections from the auditory cortex (AC). However, our understanding of these pathways has been limited by an incomplete picture of their functional influence within the three-dimensional space of the IC. Our goal was to study the properties and spatial representation of corticofugal input in the IC of guinea pigs with a high degree of spatial resolution. We systematically mapped neural activity in the IC using two types of silicon substrate probes that allow for simultaneous recording at multiple neural sites. One probe provided a high resolution in the dorsal-ventral plane and the other provided spatial resolution in the medial-lateral plane. Electrical stimulation of the ipsilateral AC produced excitatory responses in the IC with thresholds usually below 5–10 ”A. First spike latencies were predominantly in the 6–20 ms range, although latencies from 3–5 ms were also observed. Broadly distributed unimodal spike patterns with modal latencies greater than 30 ms were occasionally seen. The excitatory responses to cortical stimulation were mostly unimodal and occasionally bimodal with a wide range of spike distribution patterns and response durations. Excitation was often followed by suppression of spontaneous activity. Suppression of acoustic responses was observed even when there was little or no response to electrical stimulation, suggesting spatial-temporal integration. A few of the responding neurons showed purely inhibitory responses to electrical stimulation, suggesting that there are disynaptic routes of corticocollicular inhibition. Detailed spatial mapping revealed that the response patterns and their durations had a characteristic spatial distribution in the IC.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46534/1/221_2003_Article_1671.pd

    Analysis of transcripts differentially expressed between fruited and deflowered ‘Gala’ adult trees: a contribution to biennial bearing understanding in apple

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    Background The transition from vegetative to floral state in shoot apical meristems (SAM) is a key event in plant development and is of crucial importance for reproductive success. In perennial plants, this event is recurrent during tree life and subject to both within-tree and between-years heterogeneity. In the present study, our goal was to identify candidate processes involved in the repression or induction of flowering in apical buds of adult apple trees. Results Genes differentially expressed (GDE) were examined between trees artificially set in either ‘ON’ or ‘OFF’ situation, and in which floral induction (FI) was shown to be inhibited or induced in most buds, respectively, using qRT-PCR and microarray analysis. From the period of FI through to flower differentiation, GDE belonged to four main biological processes (i) response to stimuli, including response to oxidative stress; (ii) cellular processes, (iii) cell wall biogenesis, and (iv) metabolic processes including carbohydrate biosynthesis and lipid metabolic process. Several key regulator genes, especially TEMPRANILLO (TEM), FLORAL TRANSITION AT MERISTEM (FTM1) and SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) were found differentially expressed. Moreover, homologs of SPL and Leucine-Rich Repeat proteins were present under QTL zones previously detected for biennial bearing. Conclusions This data set suggests that apical buds of ‘ON’ and ‘OFF’ trees were in different physiological states, resulting from different metabolic, hormonal and redox status which are likely to contribute to FI control in adult apple trees. Investigations on carbohydrate and hormonal fluxes from sources to SAM and on cell detoxification process are expected to further contribute to the identification of the underlying physiological mechanisms of FI in adult apple trees

    An overview of the mid-infrared spectro-interferometer MATISSE: science, concept, and current status

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    MATISSE is the second-generation mid-infrared spectrograph and imager for the Very Large Telescope Interferometer (VLTI) at Paranal. This new interferometric instrument will allow significant advances by opening new avenues in various fundamental research fields: studying the planet-forming region of disks around young stellar objects, understanding the surface structures and mass loss phenomena affecting evolved stars, and probing the environments of black holes in active galactic nuclei. As a first breakthrough, MATISSE will enlarge the spectral domain of current optical interferometers by offering the L and M bands in addition to the N band. This will open a wide wavelength domain, ranging from 2.8 to 13 um, exploring angular scales as small as 3 mas (L band) / 10 mas (N band). As a second breakthrough, MATISSE will allow mid-infrared imaging - closure-phase aperture-synthesis imaging - with up to four Unit Telescopes (UT) or Auxiliary Telescopes (AT) of the VLTI. Moreover, MATISSE will offer a spectral resolution range from R ~ 30 to R ~ 5000. Here, we present one of the main science objectives, the study of protoplanetary disks, that has driven the instrument design and motivated several VLTI upgrades (GRA4MAT and NAOMI). We introduce the physical concept of MATISSE including a description of the signal on the detectors and an evaluation of the expected performances. We also discuss the current status of the MATISSE instrument, which is entering its testing phase, and the foreseen schedule for the next two years that will lead to the first light at Paranal.Comment: SPIE Astronomical Telescopes and Instrumentation conference, June 2016, 11 pages, 6 Figure
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