229 research outputs found
NDM-519: WIND TESTING OF SPAN-WIRE TRAFFIC SIGNAL SYSTEMS
Traffic signals are a critical part of the transportation infrastructure and it is important that they be robust enough to resist extreme wind storms lasting several hours. Failure of the signal systems results in unsafe traffic conditions during and after a storm, and the time taken for repairs delays recovery. A significant fraction of existing signals use span-wire supporting systems. The wire spans can range from 15 m to 60 m, depending on the width of the highway intersection, and exhibit nonlinear characteristics. The typical signal system used in Florida consists of the signal units, a catenary wire, hangers, a tensioned messenger wire, and the end support posts. The hangers are connected to the catenary wire at their upper ends and to the signal units at their lower end. They are also connected to the messenger wire just above the signal units. In light winds the weight of the signals is taken by the catenary wire and swinging of the signals is restrained by the messenger wire. In strong winds the combination of drag and lift forces on the signal units can result in substantial movement of the signals and changes in wire tension. To study the response of these types of system in strong winds the Florida State Department of Transportation has sponsored a research program at the Wall of Wind laboratory at Florida International University. The paper describes the development of a test rig that allows the non-linear response of the full scale signals to real wind conditions to be studied as a function of wind speed and direction. Preliminary results are also described, including the identification of an aerodynamic instability that can cause large amplitude oscillations of the whole signal system. The onset speed for the instability is a function of a number of parameters but most important are the signal geometry, the hanger design and the wire span
Re: A review of continuous vs intermittent androgen deprivation therapy: Redefining the gold standard in the treatment of advanced prostate cancer. Myths, facts and new data on a ?perpetual dispute?
Objectives: To review the literature and present new data of continuous androgen deprivation therapy (ADT) vs intermittent androgen deprivation (IAD) as therapies for prostate cancer in terms of survival and quality of life and clarify practical issues in the use of IAD. Materials and Methods: We conducted a systematic search on Medline and Embase databases using “prostatic neoplasm” and “intermittent androgen deprivation” as search terms. We reviewed meta-analyses, randomised controlled trials, reviews, clinical trials and practise guidelines written in English from 2000 and onwards until 01/04/2013. Ten randomized controlled trials were identified. Seven of them published extensive data and results randomizing 4675 patients to IAD versus CAD. Data from the other three randomized trials were limited. Results: Over the last years studies confirmed that IAD is an effective alternative approach to hormonal deprivation providing simultaneously several potential benefits in terms of quality of life and cost effectiveness. Thus, in patients with non metastatic, advanced prostate cancer IAD could be used as standard treatment, while in metastatic prostate cancer IAD role still remains ambiguous. Conclusions: Nowadays, revaluation of the gold standard of ADT in advanced prostate cancer appears essential. Recent data established that IAD should no longer be considered as investigational, since its effectiveness has been proven, especially in patients suffering from non-metastatic advanced prostate cancer
Identification of a response amplitude operator for ships
At the European Study Group Mathematics with Industry 2012 in Eindhoven, the Maritime Research Institute Netherlands (MARIN) presented the problem of identifying the response amplitude operator (RAO) for a ship, given input information on the amplitudes of the sea waves and output information on the movement of the ship. We approach the problem from a threefold perspective: a direct least-squares approach, an approach based on truncated Fourier series, and an approach using low-dimensional measures of the RAO. We give a few recommendations for possible further investigations
Identification of a Response Amplitude Operator for Ships
At the European Study Group Mathematics with Industry 2012 in Eindhoven, the Maritime Research Institute Netherlands (MARIN) presented the problem of identifying the response amplitude operator (RAO) for a ship, given input information on the amplitudes of the sea waves and output information on the movement of the ship. We approach the problem from a threefold perspective: a direct least-squares approach, an approach based on truncated Fourier series, and an approach using low-dimensional measures of the RAO. We give a few recommendations for possible further investigations
Multifaceted Simulations Reproducing Experimental Results from the 1.5-MW 140-GHz Preprototype Gyrotron for W7-X
A multifaceted simulation procedure, addressing the electron beam properties, the beam-wave interaction, and the internal losses, has been used for the simulation of the experimental operation of a 1.5-MW 140-GHz short-pulse preprototype gyrotron. The preprototype is related to the development of 1.5-MW gyrotrons for the upgrade of the electron cyclotron resonance heating system at the stellarator W7-X. A very good reproduction of experimental results has been achieved by simulation, without resorting to arbitrary speculations. This validated the numerical tools as well as the design and fabrication of the short-pulse preprototype, which fully reached the target of efficient 1.5-MW operation in millisecond pulses. Special attention has been given to simulating the possibility of parasitic after-cavity interaction in the gyrotron launcher. Also, parasitic backward-wave excitation in the gyrotron cavity has been demonstrated by simulation, at a frequency and voltage range in agreement with experimentally observed parasitic oscillations. This offers an additional possibility with respect to the origin of deleterious parasitic oscillations in high-power gyrotrons, which are usually attributed mainly to the gyrotron beam tunnel
Toxoplasma ceramide synthases: Gene duplication, functional divergence, and roles in parasite fitness.
Toxoplasma gondii is an obligate, intracellular apicomplexan protozoan parasite of both humans and animals that can cause fetal damage and abortion and severe disease in the immunosuppressed. Sphingolipids have indispensable functions as signaling molecules and are essential and ubiquitous components of eukaryotic membranes that are both synthesized and scavenged by the Apicomplexa. Ceramide is the precursor for all sphingolipids, and here we report the identification, localization and analyses of the Toxoplasma ceramide synthases TgCerS1 and TgCerS2. Interestingly, we observed that while TgCerS1 was a fully functional orthologue of the yeast ceramide synthase (Lag1p) capable of catalyzing the conversion of sphinganine to ceramide, in contrast TgCerS2 was catalytically inactive. Furthermore, genomic deletion of TgCerS1 using CRISPR/Cas-9 led to viable but slow-growing parasites indicating its importance but not indispensability. In contrast, genomic knock out of TgCerS2 was only accessible utilizing the rapamycin-inducible Cre recombinase system. Surprisingly, the results demonstrated that this "pseudo" ceramide synthase, TgCerS2, has a considerably greater role in parasite fitness than its catalytically active orthologue (TgCerS1). Phylogenetic analyses indicated that, as in humans and plants, the ceramide synthase isoforms found in Toxoplasma and other Apicomplexa may have arisen through gene duplication. However, in the Apicomplexa the duplicated copy is hypothesized to have subsequently evolved into a non-functional "pseudo" ceramide synthase. This arrangement is unique to the Apicomplexa and further illustrates the unusual biology that characterize these protozoan parasites. [Abstract copyright: © 2023 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.
Synchronous Primary Adenocarcinoma and Ancient Schwannoma in the Colon: An Unusual Case Report
Gastrointestinal schwannomas are uncommon stromal tumors of the intestinal tract and colon schwannomas are extremely rare. We report a rare case of ascending colon schwannoma with associated synchronous adenocarcinoma of the sigmoid colon. A 68-year-old man presented with a 20-day history of bleeding per rectum. Colonoscopy revealed a mass of 4.2 cm in diameter with endoluminal protrusion in the sigmoid colon and a second submucosal tumor in the ascending colon. Surgical intervention was suggested and ileo-hemicolectomy was done. Microscopically, the submucosal tumor of 4 cm in diameter showed features of schwannoma with degenerative change (ancient schwannoma). Lesional cells were positive for S100p and negative for actin, desmin, CD34, CD117, and pankeratin. The mass showed features of an invasive moderately differentiated adenocarcinoma. Colon schwannoma is a rare submucosal tumor, and the incidental occurrence with adenocarcinoma has not been well described in the literature
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