9,406 research outputs found

    Model Unspecific Search in CMS

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    We present the results of a model independent analysis, which systematically scans the data taken by CMS for deviations from the Standard Model predictions. Due to the minimal theoretical bias this approach is sensitive to a variety of models for new physics. Events with at least one electron or muon are classified according to their content of reconstructed objects (muons, electrons, photons, jets and missing transverse energy). A broad scan of three kinematic distributions in those classes is performed by identifying deviations from Standard Model expectations, accounting for systematic uncertainties.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 2 pages, 3 figur

    A Case Report of Water Hemlock Poisoning

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    Introduction: Water hemlock poisoning is an uncommon cause of seizures, gastrointestinal upset, and renal failure. This poisoning occurs infrequency and is likely to go unrecognized without a proper history and consideration in the differential diagnosis. Clinical Findings: A 23-year-old male with an unremarkable past medical history presented to the emergency department after being found unresponsive at a farm where he was employed. He had several tonic-clonic seizures en route. Initial evaluation was unremarkable and included toxicology screening, lumbar puncture, and brain imaging. Main diagnoses, therapeutics, interventions, and outcomes: The patient was treated with broad-spectrum antibiotics and antivirals with a suspected diagnosis of viral encephalitis. Over the next several days of hospitalization, he developed severe rhabdomyolysis and renal failure, and dialysis was anticipated. Upon further investigation, it was discovered that on the morning of his presentation, the patient made himself tea with a plant he had dug up while fly fishing. He believed the plant was valerian root after researching it on the Internet. The plant was later identified as water hemlock. With supportive care, the patient’s mentation cleared, and his renal failure spontaneously resolved without the need for dialysis. His symptoms fully resolved, and he was discharged home. Conclusions: This case illustrates an unusual etiology of seizures and rhabdomyolysis and the need for careful history taking. The interest in nontraditional medicine and the ease of finding amateur foraging data on the internet have greatly raised the possibility of accidental toxic ingestions

    Global aerodynamic instability of twin cylinders in cross flow

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    This paper comprises an in-depth physical discussion of the flow-induced vibration of two circular cylinders in view of the time-mean lift force on stationary cylinders and interaction mechanisms. The gap-spacing ratio T/D is varied from 0.1 to 5 and the attack angle a from 0¡ to 180¡ where T is the gap width between the cylinders and D is the diameter of a cylinder. Mechanisms of interaction between two cylinders are discussed based on time-mean lift, fluctuating lift, flow structures and flow-induced responses. The whole regime is classified into seven interaction regimes, i.e., no interaction regime; boundary layer and cylinder interaction regime; shear-layer/wake and cylinder interaction regime; shear-layer and shear-layer interaction regime; vortex and cylinder interaction regime; vortex and shear-layer interaction regime; and vortex and vortex interaction regime. Though a single non-interfering circular cylinder does not correspond to a galloping following quasi-steady galloping theory, two circular cylinders experience violent galloping vibration due to shear-layer/wake and cylinder interaction as well as boundary layer and cylinder interaction. A larger magnitude of fluctuating lift communicates to a larger amplitude vortex excitation.http:// www.elsevier.com/locate/jfshb2013ai201

    Two interacting cylinders in cross flow

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    Cylindrical structures in a group are frequently seen on land and in the ocean. Mutual flow interaction between the structures makes the wake very excited or tranquil depending on the spacing between the structures. The excited wake-enhancing forces in some cases cause a catastrophic failure of the structures. This paper presents results of an experimental investigation of Strouhal number (St), time-mean, and fluctuating forces on, and flow structures around, two identical circular cylinders at stagger angle α = 0 ◦–180 ◦ and gap-spacing ratio T/D = 0.1–5, where T is the gap width between the cylinders, and D is the diameter of a cylinder. While forces were measured using a load cell, St was from spectral analysis of fluctuating pressures measured on the side surfaces of the cylinders. A flow visualization test was conducted to observe flow structures around the cylinders. Based on forces, St, and flow structures, 19 distinct flow categories in the ranges of α and T/D investigated are observed, including one quadristable flow, three kinds of tristable flows, and four kinds of bistable flows. The quadristable, tristable, and bistable flows ensue from instabilities of the gap flow, shear layers, vortices, separation bubbles, and wakes, engendering a strong jump or drop in forces and St of the cylinders. The two cylinders interact with each other in six different mechanisms, namely interaction between boundary layer and cylinder, shear layer or wake and cylinder, shear layer and shear layer, vortex and cylinder, vortex and shear layer, and vortex and vortex. While the interaction between vortex and cylinder results in a very high fluctuating drag, that between vortex and shear layer results in a high fluctuating lift. On the other hand, the interaction between shear layer or wake and cylinder weakens mean and fluctuating forces and flow unsteadiness. A mutual discussion of forces, St, and flow structures is presented in this paper.NRF grant no A0U368, UP RDP Grant No. AOT366, UP Research and Innovation Support grant no AOS971.http://pre.aps.orgai201

    Fluid dynamics around twin cylinders and interactions

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    Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.Multiple cylindrical structures are widely seen in engineering. Flow interference between the structures leads to a very high fluctuating forces, structural vibrations, acoustic noise, or resonance, which in some cases can trigger failure. Recently circular pins in various arrays have been using as fins to enhance the cooling effect. While the enhancement is directly connected to nature of flow around the pins, no much is known of physics of flow around the pins. The knowledge of flow around two cylinders is insightful for understanding the flow around an array of cylinders/pins. This paper presents results of an experimental investigation into interactions between flowing fluid and a cylinder that is neighbored by another cylinder of the same diameter. Strouhal number (St), time-mean and fluctuating forces on and flow structures around the cylinder are investigated while the gap-spacing ratio T/D is varied from 0.1 to 5 and the attack angle a from 0 to 180 where T is the gap width between the cylinders, and D is the diameter of a cylinder. A flow visualisation test was conducted to observe flow structures around the cylinders. Based on forces, St, flow structures and fluid-cylinder interaction mechanisms, 19 distinct flow categories in the ranges of a and T/D are observed, including one quadristable flow, three tristable flows and four bistable flows. The quadristable, tristable and bistable flows ensue from instabilities of the gap flow, shear layers, vortices, separation bubbles and wakes, engendering a strong jump/drop in forces and St of the cylinders. Six different interaction mechanisms are observed, namely interaction between boundary layer and cylinder, shear layer/wake and cylinder, shear layer and shear layer, vortex and cylinder, vortex and shear layer, and vortex and vortex. While the interaction between vortex and cylinder results in a very high fluctuating drag, that between vortex and shear layer results in a high fluctuating lift. On the other hand, the interaction between shear layer/wake and cylinder suppresses mean and fluctuating forces as well as weakens flow unsteadiness for stationary cylinders but may cause violent galloping vibration when the cylinders are elastic. The interaction between boundary layer and cylinder also may generate galloping vibrations.mp201

    YourMOOC4all: a recommender system for MOOCs based on collaborative filtering implementing UDL

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    YourMOOC4all is a pilot research project to collect feedback requests regarding accessible design for Massive Open Online Courses (MOOCs). In this online application, a specific website offers the possibility for any learner to freely judge if a particular MOOC complies Universal Design for Learning (UDL) principles. User feedback is of great value for the future development of MOOC platforms and MOOC educational resources, as it will help to follow De-sign for All guidelines. YourMOOC4all is a recommender system which gathers valuable information directly from learners to improve aspects such as the quality, accessibility and usability of this online learning environment. The final objective of collecting user’s feedback is to advice MOOC providers about the missing means for meeting learner needs. This paper describes the pedagogical and technological background of YourMOOC4all and its use cases

    Dermanyssus gallinae in layer farms in Kosovo: a high risk for salmonella prevalence

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    Background The poultry red mite (PRM), Dermanyssus gallinae (D.g.) is a serious ectoparasitic pest of poultry and potential pathogen vector. The prevalence of D. g. and the prevalence of Salmonella spp. within mites on infested laying poultry farms were investigated in Kosovo. Findings In total, 14 populated layer farms located in the Southern Kosovo were assessed for D. g. presence. Another two farms in this region were investigated 6 months after depopulation. Investigated flocks were all maintained in cages, a common housing system in Kosovo. A total of eight farms were found to be infested with D. g. (50%) at varying levels, including the two depopulated farms. The detection of Salmonella spp. from D. g. was carried out using PCR. Out of the eight layer farms infested with D. g., Salmonella spp. was present in mites on three farms (37.5%). Conclusions This study confirms the high prevalence of D. g. in layer flocks in Kosovo and demonstrates the link between this mite and the presence of Salmonella spp. on infested farms
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