2,015 research outputs found

    Analysis of reinforced concrete structures with occurrence of discrete cracks at arbitrary positions

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    A nonlinear analysis of in-plane loaded plates is presented, which eliminates the disadvantages of the smeared crack approach. The elements used and the computational method are discussed. An example is shown in which one or more discrete cracks are dominant

    Secure Sparse Gradient Aggregation in Distributed Architectures

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    Federated Learning allows multiple parties to train a model collaboratively while keeping data locally. Two main concerns when using Federated Learning are communication costs and privacy. A technique proposed to significantly reduce communication costs and increase privacy is Partial Weight Sharing (PWS). However, this method is insecure due to the possibility to reconstruct the original data from the partial gradients, called inversion attacks. In this paper, we propose a novel method to successfully combine these PWS and Secure Multi-Party Computation, a method for increasing privacy. This is done by making clients share the same part of their gradient, and adding noise to those entries, which are canceled on aggregation. We show that this method does not decrease the accuracy compared to existing methods while preserving privacy

    Phase specific suppression of neutrophil function in hibernating Syrian hamster

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    Hibernation consists of alternating periods of reduced metabolism (torpor) with brief periods of metabolism similar to summer euthermia (arousal). The function of the innate immune system is reduced during hibernation, of which the underlying mechanisms are incompletely understood. Here, we studied neutrophil functionality during hibernation in Syrian hamsters. The inflammatory response to LPS-induced endotoxemia is inhibited in hibernation, partly mediated by reduced IL-6 production in early arousal. Furthermore, neutrophil pathogen binding, phagocytosis and oxidative burst is profoundly reduced in early arousal. Functionality of both summer and early arousal neutrophils was repressed in plasma from early arousal and mixed plasma from early arousal and summer euthermic, but restored by summer euthermic plasma, signifying that a plasma factor in early arousal inhibits TLR-recognition. Identification of the inhibiting factor may offer a target to modulate neutrophil function with relevance to (auto-)inflammatory diseases

    WASP-4 Is Accelerating toward the Earth

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    The orbital period of the hot Jupiter WASP-4b appears to be decreasing at a rate of −8.64 ± 1.26 ms yr⁻¹, based on transit-timing measurements spanning 12 yr. Proposed explanations for the period change include tidal orbital decay, apsidal precession, and acceleration of the system along the line of sight. To investigate further, we performed new radial-velocity measurements and speckle imaging of WASP-4. The radial-velocity data show that the system is accelerating toward the Sun at a rate of −0.0422 ± 0.0028 m s⁻¹ day⁻¹. The associated Doppler effect should cause the apparent period to shrink at a rate of −5.94 ± 0.39 ms yr⁻¹, comparable to the observed rate. Thus, the observed change in the transit period is mostly or entirely produced by the line-of-sight acceleration of the system. This acceleration is probably caused by a wide-orbiting companion of mass 10–300 M_(Jup) and orbital distance 10–100 au, based on the magnitude of the radial-velocity trend and the nondetection of any companion in the speckle images. We expect that the orbital periods of one out of three hot Jupiters will change at rates similar to WASP-4b, based on the hot-Jupiter companion statistics of Knutson et al. Continued radial-velocity monitoring of hot Jupiters is therefore essential to distinguish the effects of tidal orbital decay or apsidal precession from line-of-sight acceleration

    Decreased incidence of isolated tumor cells in lymph nodes after laparoscopic resection for colorectal cancer

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    Laparoscopic surgery has potential for less tumor cell spread because of the no-touch technique. We assessed the effect of the surgical approach (open versus no-touch laparoscopic) on the presence of tumor cells in sentinel lymph nodes (SN) of patients with stage I and II colorectal cancer. A single-center consecutive prospective series of patients operated on for colorectal cancer was analyzed. After conventional hematoxylin and eosin (H&E) staining, 107 patients without lymphatic metastases were included; 59 patients had open surgery, and 48 patients underwent laparoscopic resection. Patients in the laparoscopic group underwent a no-touch medial to lateral approach, whereas the conventional lateral to medial approach was applied in open surgery. A SN procedure was performed in all patients. The SNs were immunohistochemically analyzed for presence of occult tumor cells (OTC). According to the American Joint Committee on Cancer (AJCC) these tumor cells were divided into micrometastases (0.2-2 mm) or isolated tumor cells (ITC, 3.5 cm. Logistic regression analysis identified lymphovascular invasion as a predictor for micrometastases [odds ratio (OR) 18.4], whereas open resection was predictive for presence of ITC (OR 3.3). No-touch medial to lateral laparoscopic surgery results in less isolated tumor cells in lymph nodes compared with open lateral to medial surgery in patients with stage I and II colorectal cance
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