514 research outputs found

    Random Teachers are Good Teachers

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    In this work, we investigate the implicit regularization induced by teacher-student learning dynamics in self-distillation. To isolate its effect, we describe a simple experiment where we consider teachers at random initialization instead of trained teachers. Surprisingly, when distilling a student into such a random teacher, we observe that the resulting model and its representations already possess very interesting characteristics; (1) we observe a strong improvement of the distilled student over its teacher in terms of probing accuracy. (2) The learned representations are data-dependent and transferable between different tasks but deteriorate strongly if trained on random inputs. (3) The student checkpoint contains sparse subnetworks, so-called lottery tickets, and lies on the border of linear basins in the supervised loss landscape. These observations have interesting consequences for several important areas in machine learning: (1) Self-distillation can work solely based on the implicit regularization present in the gradient dynamics without relying on any dark knowledge, (2) self-supervised learning can learn features even in the absence of data augmentation and (3) training dynamics during the early phase of supervised training do not necessarily require label information. Finally, we shed light on an intriguing local property of the loss landscape: the process of feature learning is strongly amplified if the student is initialized closely to the teacher. These results raise interesting questions about the nature of the landscape that have remained unexplored so far. Code is available at https://github.com/safelix/dinopl

    Gas exchange calculation may estimate changes in pulmonary blood flow during veno-arterial extracorporeal membrane oxygenation in a porcine model.

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    BACKGROUND Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used as rescue for severe cardiopulmonary failure. We tested whether the ratio of CO2 elimination at the lung and the ECMO (VCO2ECMO/VCO2Lung) would reflect the ratio of respective blood flows and could be used to estimate changes in pulmonary blood flow (QLUNG), i. e. native cardiac output. METHODS Four healthy pigs were centrally cannulated for VA-ECMO. We measured blood flows with an ultrasonic flow probes. VCO2ECMO and VCO2Lung were calculated from sidestream capnographs under constant pulmonary ventilation during ECMO weaning with changing sweep gas and/or ECMO blood flow. If ventilation/perfusion (V/Q) ratio of ECMO was not one, the VCO2ECMO was normalized to V/Q=1 (VCO2ECMONORM). Changes in pulmonary blood flow were calculated using the relationship between changes in CO2 elimination and ECMO blood flow. RESULTS QECMO correlated strongly with VCO2ECMONORM (r2 0.95 - 0.99). QLUNG correlated well with VCO2LUNG (r2 0.65 - 0.89, p<=0.002). Absolute QLung could not be calculated in a non-steady state. Calculated pulmonary blood flow changes had a bias of 76 (-266 to 418) ml/min and correlated with measured QLUNG (r2 0.974 - 1.000, p = 0.1 to 0.006) for cumulative ECMO flow reductions. CONCLUSIONS VCO2 of the lung correlated strongly with pulmonary blood flow. Our model could predict pulmonary blood flow changes within clinically acceptable margins of error. The prediction is made possible with a normalization to a V/Q of 1 for ECMO. This approach depends on measurements readily available and may allow immediate assessment of the cardiac output response

    Sero-epidemiological survey for alveolar echinococcosis (by Em2-ELISA) of blood donors in an endemic area of Switzerland

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    Sera from 17 166 blood donors living in 10 cantons of northern Switzerland in an area endemic for Echinococcus multilocularis were investigated by serological survey for alveolar echinococcosis (AE). A highly species-specific antigen (Em2) and a commonly used E. granulosus hydatid fluid antigen (EgHF) were compared for their suitability in seroepidemiology. EgHF showed a degree of nonspecificity which did not allow direct detection of AE cases. Antibody reaction with Em2 resulted in the detection of 2 asymptomatic clinical cases of AE (seroprevalence 0·01%) within this population of blood donors. A further 4 persons were positive in Em2-ELISA. These 4 persons had negative imaging studies and will be followed serologically and clinicall

    What is campus bridging and what is XSEDE doing about it?

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    The term “campus bridging” was first used in the charge given to an NSF Advisory Committee for Cyberinfrastructure task force. That task force developed this description of campus bridging: “Campus bridging is the seamlessly integrated use of cyberinfrastructure operated by a scientist or engineer with other cyberinfrastructure on the scientist’s campus, at other campuses, and at the regional, national, and international levels as if they were proximate to the scientist, and when working within the context of a Virtual Organization (VO) make the ‘virtual’ aspect of the organization irrelevant (or helpful) to the work of the VO.” Campus bridging is more a viewpoint and a set of approaches to usability, software, and information concerns than a particular set of tools or software. We outline here several specific use cases that have been identified as priorities for XSEDE in the next four years. These priorities include documentation, deployment of software used entirely outside of XSEDE, and software that helps bridge from individual researcher to campus to XSEDE cyberinfrastructure. We also describe early pilot tests and means by which the user community may stay informed of campus bridging activities and participate in the implementation of Campus Bridging tools created by XSEDE. Metrics are still being developed, and will include (1) the number of campuses that adopt and use Campus Bridging tools developed by XSEDE and (2) the number of and extent to which XSEDE-developed Campus Bridging tools are adopted among other CI projects.The work described here was supported by National Science Foundation Award Nos. 0932251, 0503697, 1002526, 1059812, 1040777, 0723054, 0521433, and 0504075

    High-speed motility originates from cooperatively pushing and pulling flagella bundles in bilophotrichous bacteria.

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    Funder: Max-Planck-Gesellschaft; FundRef: http://dx.doi.org/10.13039/501100004189Funder: IMPRS on Multiscale BiosystemsFunder: French National Research Agency; FundRef: http://dx.doi.org/10.13039/501100001665; Grant(s): ANR Tremplin-ERC: ANR-16-TERC-0025-01Bacteria propel and change direction by rotating long, helical filaments, called flagella. The number of flagella, their arrangement on the cell body and their sense of rotation hypothetically determine the locomotion characteristics of a species. The movement of the most rapid microorganisms has in particular remained unexplored because of additional experimental limitations. We show that magnetotactic cocci with two flagella bundles on one pole swim faster than 500 µm·s-1 along a double helical path, making them one of the fastest natural microswimmers. We additionally reveal that the cells reorient in less than 5 ms, an order of magnitude faster than reported so far for any other bacteria. Using hydrodynamic modeling, we demonstrate that a mode where a pushing and a pulling bundle cooperate is the only possibility to enable both helical tracks and fast reorientations. The advantage of sheathed flagella bundles is the high rigidity, making high swimming speeds possible

    Overexpression of eIF3a in Squamous Cell Carcinoma of the Oral Cavity and Its Putative Relation to Chemotherapy Response

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    The eukaryotic translation initiation factor eIF3a is one of the core subunits of the translation initiation complex eIF3, responsible for ribosomal subunit joining and mRNA recruitment to the ribosome. It is known to play an important role in general translation initiation as well as in the specific translational regulation of various gene products, among which many influence tumour development, progression, and the therapeutically important pathways of DNA damage repair. Therefore, beyond its role in protein synthesis, eIF3a is emerging as regulator in tumour pathogenesis and therapy response and, therefore, a potential tumor marker. By means of a tissue microarray (TMA) for histopathological and statistical assessment, we here show eIF3a expression in 103 cases of squamous cell carcinoma of the oral cavity (OSCC), representing tissues from 103 independent patients. A subset of the study cohort was treated with platinum based therapy. Our results show that the 170 kDa protein is upregulated in OSCC and correlates with good overall survival. Overexpressing tumors respond better to platinum-based chemotherapy, suggesting eIF3a as a putative predictive as well as prognostic tumor marker in OSCC

    Kupffer Cells and Blood Monocytes Orchestrate the Clearance of Iron-Carbohydrate Nanoparticles from Serum.

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    Intravenous (IV) iron nanoparticle preparations are widely used to treat iron deficiency. The mechanism of mononuclear phagocyte system-mediated clearance of IV iron nanoparticles is unknown. The early uptake and homeostasis of iron after injection of ferric carboxymaltose (FCM) in mice was studied. An increase in serum iron was observed at 2.5 h followed by a return to baseline by 24 h. An increase in circulating monocytes was observed, particularly Ly6Chi and Ly6Clow. FCM was also associated with a time-dependent decrease in liver Kupffer cells (KCs) and increase in liver monocytes. The increase in liver monocytes suggests an influx of iron-rich blood monocytes, while some KCs underwent apoptosis. Adoptive transfer experiments demonstrated that following liver infiltration, blood monocytes differentiated to KCs. KCs were also critical for IV iron uptake and biodegradation. Indeed, anti-Colony Stimulating Factor 1 Receptor (CSF1R)-mediated depletion of KCs resulted in elevated serum iron levels and impaired iron uptake by the liver. Gene expression profiling indicated that C-C chemokine receptor type 5 (CCR5) might be involved in monocyte recruitment to the liver, confirmed by pharmaceutical inhibition of CCR5. Liver KCs play a pivotal role in the clearance and storage of IV iron and KCs appear to be supported by the expanded blood monocyte population

    Геофизический прогноз нового перспективного участка в партизанском золоторудном узле (Енисейский кряж)

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    Рассматривается обоснование аэрогеофизических признаков золото-сульфидно-вкрапленного оруденения на новом участке в Партизанском рудном узле -Подголечном, предположительно аналогичного месторождению Благодатному Северо-Енисейского района (Енисейский кряж), по результатам съемки 2012 г. (магнитометрия, электроразведка ДИП-А, гамма-спектрометрия) масштаба 1:10000

    Surface Chemistry of the Molecular Solar Thermal Energy Storage System 2,3-Dicyano-Norbornadiene/Quadricyclane on Ni(111)

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    Molecular solar thermal (MOST) systems are a promising approach for the introduction of sustainable energy storage solutions. We investigated the feasibility of the dicyano-substituted norbornadiene/quadricyclane molecule pair on Ni(111) for catalytic model studies. This derivatization is known to lead to a desired bathochromic shift of the absorption maximum of the parent compound. In our experiments further favorable properties were found: At low temperatures, both molecules adsorb intact without any dissociation. In situ temperature-programmed HR-XPS experiments reveal the conversion of (CN)2-quadricyclane to (CN)2-norbornadiene under energy release between 175 and 260 K. The absence of other surface species due to side reactions indicates full isomerization. Further heating leads to the decomposition of the molecular framework into smaller carbonaceous fragments above 290 K and finally to amorphous structures, carbide and nitride above 400 K. DFT calculations gave insights into the adsorption geometries. (CN)2-norbornadiene is expected to interact stronger with the surface, with flat configurations being favorable. (CN)2-quadricyclane exhibits smaller adsorption energies with negligible differences for flat and side-on geometries. Simulated XP spectra are in good agreement with experimental findings further supporting the specific spectroscopic fingerprints for both valence isomers

    XSEDE Campus Bridging Use Cases

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    This document is both a user-­facing document (publicly accessible) and an internal working document intended to define user needs and use cases that fall under the general umbrella of Campus Bridging within the overall activities of XSEDE.XSEDE is supported by National Science Foundation Grant 1053575 (XSEDE: eXtreme Science and Engineering Discovery Environment)
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