626 research outputs found

    Survival, Reproduction and Calcification of Three Benthic Foraminiferal Species in Response to Experimentally Induced Hypoxia

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    An experiment was conducted to test the survival rates, growth (calcification), and reproduction capacities of three benthic foraminiferal species (Ammonia tepida, Melonis barleeanus and Bulimina marginata) under strongly oxygen-depleted conditions alternating with short periods of anoxia. Protocols were determined to use accurate methods (1) to follow oxygen concentrations in the aquaria (continuously recorded using microsensors), (2) to distinguish live foraminifera (fluorogenic probe), (3) to determine foraminiferal growth (calcein-marked shells and automatic measurement of the shell size). Our results show a very high survival rate, and growth of A. tepida and M. barleeanus in all experimental conditions, suggesting that survival and growth are not negatively impacted by hypoxia. Unfortunately, no reproduction was observed for these species, so that we cannot draw firm conclusions on their ability to reproduce under hypoxic/anoxic conditions. The survival rates of Bulimina marginata are much lower than for the other two species. In the oxic treatments, the presence of juveniles is indicative of reproductive events, which can explain an important part of the mortality. The absence of juveniles in the hypoxic/anoxic treatments could indicate that these conditions inhibit reproduction. Alternatively, the perceived absence of juveniles could also be due to the fact that the juveniles resulting from reproduction (causing similar mortality rates as in the oxic treatments) were not able to calcify, and remained at a propagule stage. Additional experiments are needed to distinguish these two options

    How simple can a model of an empty viral capsid be? Charge distributions in viral capsids

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    We investigate and quantify salient features of the charge distributions on viral capsids. Our analysis combines the experimentally determined capsid geometry with simple models for ionization of amino acids, thus yielding the detailed description of spatial distribution for positive and negative charge across the capsid wall. The obtained data is processed in order to extract the mean radii of distributions, surface charge densities and dipole moment densities. The results are evaluated and examined in light of previously proposed models of capsid charge distributions, which are shown to have to some extent limited value when applied to real viruses.Comment: 10 pages, 10 figures; accepted for publication in Journal of Biological Physic

    Telemetry for Next-Generation Networks

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    Software-defined networking enables tight integration between packet-processing hardware and centralized controllers, highlighting the importance of deep network insight for informed decision-making. Modern network telemetry aims to provide per-packet insights into networks, enabling significant optimizations and security enhancements. However, the increasing gap between network speeds and the stagnating performance of CPUs presents significant challenges to these efforts. Attempts to circumvent this slowdown by deploying monitoring functionality directly into the data plane, which is capable of line-rate processing, are hindered by the hardware's resource limitations and the data collection capacities of analysis servers. This dissertation introduces a dual strategy to enhance centralized network insights: Firstly, it improves probabilistic network monitoring data structures, achieving fault-tolerant monitoring in heterogeneous environments with significantly higher accuracy and reduced resource demands. Secondly, it redesigns the interface between networking hardware and analysis servers to substantially lower telemetry collection and aggregation costs, thus enabling insights at unprecedented granularities. These advancements collectively mark a significant stride towards realizing the full potential of fine-grained network monitoring, offering a scalable and efficient solution to address the challenges brought by the rapid evolution of network technologies

    Antibody-mediated inhibition of the FGFR1c isoform induces a catabolic lean state in Siberian hamsters

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    Hypothalamic tanycytes are considered to function as sensors of peripheral metabolism [1]. To facilitate this role, they express a wide range of receptors, including fibroblast growth factor receptor 1 (FGFR1). Using a monoclonal antibody (IMC-H7) that selectively antagonizes the FGFR1c isoform [2], we investigated possible actions of FGFR1c in a natural animal model of adiposity, the Siberian hamster. Infusion of IMC-H7 into the third ventricle suppressed appetite and increased energy expenditure. Likewise, peripheral treatment with IMC-H7 decreased appetite and body weight and increased energy expenditure and fat oxidation. A greater reduction in body weight and caloric intake was observed in response to IMC-H7 during the long-day fat state as compared to the short-day lean state. This enhanced response to IMC-H7 was also observed in calorically restricted hamsters maintained in long days, suggesting that it is the central photoperiodic state rather than the peripheral adiposity that determines the response to FGFR1c antagonism. Hypothalamic thyroid hormone availability is controlled by deiodinase enzymes (DIO2 and DIO3) expressed in tanycytes and is the key regulator of seasonal cycles of energy balance [3 and 4]. Therefore, we determined the effect of IMC-H7 on hypothalamic expression of these deiodinase enzymes. The reductions in food intake and body weight were always associated with decreased expression of DIO2 in the hypothalamic ependymal cell layer containing tanycytes. These data provide further support for the notion the tanycytes are an important component of the mechanism by which the hypothalamus integrates central and peripheral signals to regulate energy intake and expenditure

    Mafb lineage tracing to distinguish macrophages from other immune lineages reveals dual identity of Langerhans cells

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    Current systems for conditional gene deletion within mouse macrophage lineages are limited by ectopic activity or low efficiency. In this study, we generated a Mafb-driven Cre strain to determine whether any dendritic cells (DCs) identified by Zbtb46-GFP expression originate from a Mafb-expressing population. Lineage tracing distinguished macrophages from classical DCs, neutrophils, and B cells in all organs examined. At steady state, Langerhans cells (LCs) were lineage traced but also expressed Zbtb46-GFP, a phenotype not observed in any other population. After exposure to house dust mite antigen, Zbtb46-negative CD64(+) inflammatory cells infiltrating the lung were substantially lineage traced, but Zbtb46-positive CD64(−) cells were not. These results provide new evidence for the unique identity of LCs and challenge the notion that some inflammatory cells are a population of monocyte-derived DCs

    Abnormal Stop Band Behavior Induced by Rotational Resonance in Flexural Metamaterial

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    This paper investigates abnormal stop band behavior of resonance-based flexural elastic metamaterials under the rotational resonance motion. Due to the unique physics of flexural waves, we found that the stop band generated by the rotational resonance motion exhibits peculiar behavior which are quite different from general belief - it is shown that the negativity due to the rotational resonance does not provide any stop bands and the stop band generation due to the rotational resonance is governed by totally different band gap condition. To explain the peculiar behavior, a discrete Timoshenko beam model with both effective mass and rotational inertia as independent variables is introduced, and the wave behaviors of resonance-based flexural elastic metamaterial are precisely and fully described. The unique band gap condition, including the peculiar behavior, is derived with numerical validations. We expect our new model can provide a strong background for various flexural elastic metamaterials which can be effectively applied in various vibration devices

    Impact of safety-related dose reductions or discontinuations on sustained virologic response in HCV-infected patients: Results from the GUARD-C Cohort

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    BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced 651 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with 651 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not 655. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin

    Etiology, management, and outcome of the Budd-Chiari syndrome

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    Background: The Budd-Chiari syndrome (BCS) is hepatic venous outflow obstruction. What is known about the syndrome is based on small studies of prevalent cases. Objective: To characterize the causes and treatment of incident BCS. Design: Consecutive case series of patients with incident BCS, enrolled from October 2003 to October 2005 and followed until May 2006. Setting: Academic and nonacademic hospitals in France, Spain, Italy, Great Britain, Germany, Belgium, the Netherlands, Portugal, and Switzerland. Patients: Persons older than 16 years with definite hepatic outflow obstruction diagnosed by imaging. Persons with hepatic outflow obstruction due to heart failure, sinusoidal obstruction syndrome, cancer, or liver transplantation were excluded. Measurements: Signs and symptoms; laboratory and imaging findings; diagnosis; treatment; and overall, transplantation-free, and intervention-free survival. Results: 163 incident cases of BCS were identified. Median follow-up was 17 months (range, 0.1 to 31 months). Most patients (84%) had at least 1 thrombotic risk factor, and many (46%) had more than 1; the most common was myeloproliferative disorders (49% of 103 tested patients). Patients were mainly treated with anticoagulation (140 patients [86%]), transjugular intrahepatic portosystemic shunting (56 patients [34%]), or liver transplantation (20 patients [12%]), and 80 patients (49%) were managed noninvasively. Only 3 patients underwent surgical shunting. The survival rate was 87% (95% CI, 82% to 93%) at 1 year and 82% (CI, 75% to 88%) at 2 years. Limitation: Treatment was not standardized across all centers, and data on important clinical variables were missing for some patients. Conclusion: Most patients with BCS have at least 1 thrombotic risk factor, and many have more than 1; myeloproliferative disorders are most common. One- and 2-year survival rates are good with contemporary management, which includes noninvasive therapies (anticoagulation and diuretics) and invasive techniques. Transjugular intrahepatic portosystemic shunting seems to have replaced surgical shunting as the most common invasive therapeutic procedure. Primary Funding Source: Fifth Framework Programme of the European Commission

    Lightweight Acquisition and Ranging of Flows in the Data Plane

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    As networks get more complex, the ability to track almost all the flows is becoming of paramount importance. This is because we can then detect transient events impacting only a subset of the traffic. Solutions for flow monitoring exist, but it is getting very difficult to produce accurate estimations for every tuple given the memory constraints of commodity programmable switches. Indeed, as networks grow in size, more flows have to be tracked, increasing the number of tuples to be recorded. At the same time, end-host virtualization requires more specific flowIDs, enlarging the memory cost for every single entry. Finally, the available memory resources have to be shared with other important functions as well (e.g., load balancing, forwarding, ACL). To address those issues, we present FlowLiDAR (Flow Lightweight Detection and Ranging), a new solution that is capable of tracking almost all the flows in the network while requiring only a modest amount of data plane memory, which is not dependent on the size of flowIDs. We implemented the scheme in P4, tested it using real traffic from ISPs, and compared it against four state-of-the-art solutions: FlowRadar, NZE, PR-sketch, and Elastic Sketch
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