883 research outputs found
An Optimal Number-Dependent Preventive Maintenance Strategy for Offshore Wind Turbine Blades Considering Logistics
In offshore wind turbines, the blades are among the most critical and expensive components that suffer from different types of damage due to the harsh maritime environment and high load. The blade damages can be categorized into two types: the minor damage, which only causes a loss in wind capture without resulting in any turbine stoppage, and the major (catastrophic) damage, which stops the wind turbine and can only be corrected by replacement. In this paper, we propose an optimal number-dependent preventive maintenance (NDPM) strategy, in which a maintenance team is transported with an ordinary or expedited lead time to the offshore platform at the occurrence of the Nth minor damage or the first major damage, whichever comes first. The long-run expected cost of the maintenance strategy is derived, and the necessary conditions for an optimal solution are obtained. Finally, the proposed model is tested on real data collected from an offshore wind farm database. Also, a sensitivity analysis is conducted in order to evaluate the effect of changes in the model parameters on the optimal solution
Press Coverage and Political Accountability
In this paper we estimate the impact of press coverage on citizen knowledge, politicians' actions, and policy. We find that a poor fit between newspaper markets and political districts reduces press coverage of politics. We use variation in this fit due to redistricting to identify the effects of reduced coverage. Exploring the links in the causal chain of media effects -- voter information, politicians' actions and policy -- we find statistically significant and substantively important effects. Voters living in areas with less coverage of their U.S. House representative are less likely to recall their representative's name, and less able to describe and rate them. Congressmen who are less covered by the local press work less for their constituencies: they are less likely to stand witness before congressional hearings, to serve on constituency-oriented committees (perhaps), and to vote against the party line. Finally, this congressional behavior affects policy. Federal spending is lower in areas where there is less press coverage of the local members of congress.
Genuine Counterfactual Communication with a Nanophotonic Processor
In standard communication information is carried by particles or waves.
Counterintuitively, in counterfactual communication particles and information
can travel in opposite directions. The quantum Zeno effect allows Bob to
transmit a message to Alice by encoding information in particles he never
interacts with. The first suggested protocol not only required thousands of
ideal optical components, but also resulted in a so-called "weak trace" of the
particles having travelled from Bob to Alice, calling the scalability and
counterfactuality of previous proposals and experiments into question. Here we
overcome these challenges, implementing a new protocol in a programmable
nanophotonic processor, based on reconfigurable silicon-on-insulator waveguides
that operate at telecom wavelengths. This, together with our telecom
single-photon source and highly-efficient superconducting nanowire
single-photon detectors, provides a versatile and stable platform for a
high-fidelity implementation of genuinely trace-free counterfactual
communication, allowing us to actively tune the number of steps in the Zeno
measurement, and achieve a bit error probability below 1%, with neither
post-selection nor a weak trace. Our demonstration shows how our programmable
nanophotonic processor could be applied to more complex counterfactual tasks
and quantum information protocols.Comment: 6 pages, 4 figure
The use of multiplex platforms for absolute and relative protein quantification of clinical material
Abstract When introducing multiplex platforms to measure protein content in precious clinical material there is an increased risk of cross reactivity, loss of sensitivity as well as accuracy. In this paper, four multiplex platforms and one singleplex platform were compared by running pre- and post-treatment plasma samples from CML patients. We found a variation of absolute protein concentrations between platforms. For some of the analytes and platforms, relative differences between pre- and post-treatment samples correlated. We conclude that absolute concentrations measured by different platforms should be compared with caution and comparing relative differences could be more accurate.Peer reviewe
Embryogenesis and Larval Biology of the Cold-WaterCoral Lophelia pertusa
Cold-water coral reefs form spectacular and highly diverse ecosystems in the deep sea but little is known about
reproduction, and virtually nothing about the larval biology in these corals. This study is based on data from two locations
of the North East Atlantic and documents the first observations of embryogenesis and larval development in Lophelia
pertusa, the most common framework-building cold-water scleractinian. Embryos developed in a more or less organized
radial cleavage pattern from ,160 mm large neutral or negatively buoyant eggs, to 120–270 mm long ciliated planulae.
Embryogenesis was slow with cleavage occurring at intervals of 6–8 hours up to the 64-cell stage. Genetically characterized
larvae were sexually derived, with maternal and paternal alleles present. Larvae were active swimmers (0.5 mm s21) initially
residing in the upper part of the water column, with bottom probing behavior starting 3–5 weeks after fertilization.
Nematocysts had developed by day 30, coinciding with peak bottom-probing behavior, and possibly an indication that
larvae are fully competent to settle at this time. Planulae survived for eight weeks under laboratory conditions, and
preliminary results indicate that these planulae are planktotrophic. The late onset of competency and larval longevity
suggests a high dispersal potential. Understanding larval biology and behavior is of paramount importance for biophysical
modeling of larval dispersal, which forms the basis for predictions of connectivity among populations
Stratification of responders towards eculizumab using a structural epitope mapping strategy
The complement component 5 (C5)-binding antibody eculizumab is used to treat patients with paroxysmal nocturnal hemoglobinuria (PNH) and atypical haemolytic uremic syndrome (aHUS). As recently reported there is a need for a precise classification of eculizumab responsive patients to allow for a safe and cost-effective treatment. To allow for such stratification, knowledge of the precise binding site of the drug on its target is crucial. Using a structural epitope mapping strategy based on bacterial surface display, flow cytometric sorting and validation via haemolytic activity testing, we identified six residues essential for binding of eculizumab to C5. This epitope co-localizes with the contact area recently identified by crystallography and includes positions in C5 mutated in non-responders. The identified epitope also includes residue W917, which is unique for human C5 and explains the observed lack of cross-reactivity for eculizumab with other primates. We could demonstrate that Ornithodorus moubata complement inhibitor (OmCI), in contrast to eculizumab, maintained anti-haemolytic function for mutations in any of the six epitope residues, thus representing a possible alternative treatment for patients non-responsive to eculizumab. The method for stratification of patients described here allows for precision medicine and should be applicable to several other diseases and therapeutics
Picropodophyllin causes mitotic arrest and catastrophe by depolymerizing microtubules via Insulin-like growth factor-1 receptor-independent mechanism
Picropodophyllin (PPP) is an anticancer drug undergoing clinical development in NSCLC. PPP has been shown to suppress IGF-1R signaling and to induce a G2/M cell cycle phase arrest but the exact mechanisms remain to be elucidated. The present study identified an IGF-1-independent mechanism of PPP leading to pro-metaphase arrest. The mitotic block was induced in human cancer cell lines and in an A549 xenograft mouse but did not occur in normal hepatocytes/mouse tissues. Cell cycle arrest by PPP occurred in vitro and in vivo accompanied by prominent CDK1 activation, and was IGF-1R-independent since it occurred also in IGF-1R-depleted and null cells. The tumor cells were not arrested in G2/M but in mitosis. Centrosome separation was prevented during mitotic entry, resulting in a monopolar mitotic spindle with subsequent prometaphase-arrest, independent of Plk1/Aurora A or Eg5, and leading to cell features of mitotic catastrophe. PPP also increased soluble tubulin and decreased spindle-associated tubulin within minutes, indicating that it interfered with microtubule dynamics. These results provide a novel IGF-1R-independent mechanism of antitumor effects of PPP
Deglaciation of Fennoscandia
To provide a new reconstruction of the deglaciation of the Fennoscandian Ice Sheet, in the form of calendar-year time-slices, which are particularly useful for ice sheet modelling, we have compiled and synthesized published geomorphological data for eskers, ice-marginal formations, lineations, marginal meltwater channels, striae, ice-dammed lakes, and geochronological data from radiocarbon, varve, optically-stimulated luminescence, and cosmogenic nuclide dating. This 25 is summarized as a deglaciation map of the Fennoscandian Ice Sheet with isochrons marking every 1000 years between 22 and 13 cal kyr BP and every hundred years between 11.6 and final ice decay after 9.7 cal kyr BP. Deglaciation patterns vary across the Fennoscandian Ice Sheet domain, reflecting differences in climatic and geomorphic settings as well as ice sheet basal thermal conditions and terrestrial versus marine margins. For example, the ice sheet margin in the high-precipitation coastal setting of the western sector responded sensitively to climatic variations leaving a detailed record of prominent moraines and ice-marginal deposits in many fjords and coastal valleys. Retreat rates across the southern sector differed between slow retreat of the terrestrial margin in western and southern Sweden and rapid retreat of the calving ice margin in the Baltic Basin. Our reconstruction is consistent with much of the published research. However, the synthesis of a large amount of existing and new data support refined reconstructions in some areas. For example, we locate the LGM extent of the ice sheet in northwestern Russia further east than previously suggested and conclude that it occurred at a later time than the rest of the ice sheet, at around 17-15 cal kyr BP, and propose a slightly different chronology of moraine formation over southern Sweden based on improved correlations of moraine segments using new LiDAR data and tying the timing of moraine formation to Greenland ice core cold stages. Retreat rates vary by as much as an order of magnitude in different sectors of the ice sheet, with the lowest rates on the high-elevation and maritime Norwegian margin. Retreat rates compared to the climatic information provided by the Greenland ice core record show a general correspondence between retreat rate and climatic forcing, although a close match between retreat rate and climate is unlikely because of other controls, such as topography and marine versus terrestrial margins. Overall, the time slice
reconstructions of Fennoscandian Ice Sheet deglaciation from 22 to 9.7 cal kyr BP provide an important dataset for understanding the contexts that underpin spatial and temporal patterns in retreat of the
Fennoscandian Ice Sheet, and are an important resource for testing and refining ice sheet models
Biodegradation in soil effects on PLA/sisal and PHBV/sisal biocomposites
The use of bio-based composites like lignocellulosic fibres/polymer composites as an alternative materials are continuously increasing in several applications such as automobile manufacturing, packaging, construction or household and agricultural equipments. In order to warranty the durability on green biocomposites based on polymer matrixes like poly(hydroxy butyrate-co-valerate) (PHBV) and poly(lactide) (PLA), the previous knowledge about the influence of the ambient agents on their macromolecular properties is necessary. In this sense, biodegradation in soil normalised experiments are useful. In this work, two commercial PHBV and PLA were reinforced with sisal fibres at 10 %, 20% and 30% of weight, with the aid of maleic anhydride as coupling agent.the influence of the amount of sisal fiber and the effect of the coupling agent on the impact of the biodegradation in soil on the materiales, in terms of the variation of the physico-chemical properties of the biocomposites
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