Directory of Open Access Journals (Sweden)
Ankit Shah
2017-04-01
Full Text Available History of present illness: A 44-year-old female called 911 complaining of abdominal pain, but was unresponsive upon arrival by emergency medical services (EMS. She presented to the emergency department (ED as a full cardiac arrest and had return of spontaneous circulation (ROSC with cardiopulmonary resuscitation (CPR and epinephrine. The patient had a splenic embolization 1 week prior to presentation. Bedside ultrasound demonstrated free fluid throughout the abdomen. As part of the resuscitation, femoral central venous access was obtained by the Emergency Department (ED physician, and a medical student was allowed to place a Cordis over the guidewire. The attending was next to the student, though became distracted when the patient again lost pulses. The student lost control of the guidewire upon re-initiation of CPR. Another Cordis was placed in the same location by the ED physician after the guidewire was seen on a chest radiograph. The patient was taken to the operating room with massive transfusion protocol, and the guidewire was left in the vena caval system until the patient could be stabilized. Two days later, interventional radiology removed the guidewire via a right internal jugular (IJ approach without complications. The patient had a prolonged and complicated course, but was discharged home two weeks later at her baseline. Significant findings: Initial chest radiograph shows a guidewire in the inferior vena cava (IVC, superior vena cava (SVC, and right IJ veins. Discussion: Central line complications include failure to place the catheter, improper catheter location, hemothorax from vascular injury, infection, arrhythmia, and cardiac arrest1. Complications from lost guidewires include cardiac dysrhythmias, cardiac conduction abnormalities, perforation of vessels/heart chambers, kinking/looping/knotting of the wire, entanglement of previously placed intravascular devices, breakage of the tip of the wire and subsequent embolization and
A new technique for endoscopic treatment of gastric phytobezoars: fragmentation using guidewire.
Senturk, O; Hulagu, S; Celebi, A; Korkmaz, U; Duman, A E; Dindar, G; Bozkurt, N; Yilmaz, H; Ozturkler, M; Can, B; Batman, A
2014-12-01
Bezoars result from accumulation of indigestible materials in the gastrointestinal tract and often occur in the stomach. In this study, we evaluated the use of guidewires in patients with gastric phytobezoars (PBs) as a new method for PB removal and examined the safety of the procedure. Between February 2009 and January 2013, we analyzed data from 11 patients with gastric PBs. We fitted a transparent cap to a standard endoscope (EG450WR5, Fujinon), and a 0.025 inch guidewire was passed through the standart endoscope. PBs were surrounded by a loop in the guidewire and destroyed. After 2 weeks of treatment, patients were re-evaluated for effectiveness. PB fragmentation time was 5-11 minutes. In five patients with a history of gastric surgery, we needed an additional 16-28 minutes for removal of the fragments. In six patients additionally treated with enzymatic degradation after the breaking procedure, PBs completely disappeared within 2 weeks. There were no complications during the procedure. The guidewire and fragmentation procedure for PBs is an efficient and reliable method. When combined with enzymatic degradation, PBs can be managed quickly and effectively.
Kipling, MD; Rangaiah, C; Nugud, O
2011-01-01
We present the case of an unusual complication of insertion of a naso-jejunal feeding tube (NJT) using a guidewire, where the guidewire formed an alpha-loop in the naso-pharynx, becoming entrapped after cutting into the soft palate. This required ENT input and a general anaesthetic to rectify the situation.
Kipling, Md; Rangaiah, C; Nugud, O
2011-03-01
We present the case of an unusual complication of insertion of a naso-jejunal feeding tube (NJT) using a guidewire, where the guidewire formed an alpha-loop in the naso-pharynx, becoming entrapped after cutting into the soft palate. This required ENT input and a general anaesthetic to rectify the situation. © JSCR.
Directory of Open Access Journals (Sweden)
Byeong jun Ahn
2015-11-01
Full Text Available Background We hypothesized that the direction of the J-tip of the guidewire during insertion into the internal jugular vein (IJV might determine its ultimate location. Methods In this study, 300 patients between the ages of 18 and 99 years who required central venous catheterization via IJV in the emergency department enrolled for randomization. IVJ catheterization was successful in 285 of 300 patients. An independent operator randomly prefixed the direction of the J-tip of the guidewire to one of three directions. Based on the direction of the J-tip, patients were allocated into three groups: the J-tip medial-directed group (Group A, the lateral-directed group (Group B, or the downward-directed group (Group C. Postoperative chest radiography was performed on all patients in order to visualize the location of the catheter tip. A catheter is considered malpositioned if it is not located in the superior vena cava or right atrium. Results Of the total malpositioned catheter tips (8 of 285; 2.8%, the majority (5 of 8; 62.5% entered the contralateral subclavian vein, 2 (25.0% were complicated by looping, and 1 (12.5% entered the ipsilateral subclavian vein. According to the direction of the J-tip of the guidewire, the incidence of malpositioning of the catheter tip was 4 of 92 in Group A (4.3%, 4 of 96 in Group B (4.2%, and there were no malpositions in Group C. There were no significant differences among the three groups (p = 0.114. Conclusions The direction of the J-tip of the guidewire had no statistically significant effect on incidence of malpositioned tips.
International Nuclear Information System (INIS)
Katsouras, Christos S.; Michalis, Lampros K.; Malamou-Mitsi, Vassiliki D.; Niokou, Demetra; Giogiakas, Vassilios; Nikas, Dimitrios; Massouras, Gerasimos; Dallas, Pavlos; Tsetis, Dimitrios K.; Sideris, Dimitris A.; Rees, Michael R.
2003-01-01
Purpose: To compare the damage caused by vibrating guidewire manipulation and conventional guidewire manipulation of soft coronary wires in normal sheep coronary arteries. Methods: Using an intact sheep model the two methods of passing a coronary guidewire down a normal coronary artery under fluoroscopic screening control were studied. The resulting arterial damage caused by the two techniques was studied histologically. The severity of damage was scored from 1 (no damage) to 4 (severe damage) and expressed as: (a) percentage of damaged sections, (b) mean damage score per section and (c) percentage of sections suffering the most severe degree of damage (scores 3 and 4). Results: One hundred and sixty-eight sections were studied.The percentage of damaged sections was lower in the vibrating guidewire group (p 0.004). The mean damage score and the percentage of sections with a damage score of 3 or 4 were smaller in the vibrating guidewire group than in the conventional guidewire manipulation group (p = 0.001 and p =0.009, respectively). Conclusions: Both methods of guidewire manipulation cause identifiable vascular damage. The extent and severity of damage appear greater when the guidewire is manipulated manually
One-loop effective brane action
International Nuclear Information System (INIS)
Lee, T-H
2008-01-01
The one-loop effective action for a p brane embedded in a D = p+2 Minkowski spacetime in the static gauge is calculated. Rescaling the quantum fluctuation by (-g 0 ) 1/2 evaluated on the background brane leads to the one-loop effective action expressed only in terms of infrared and ultraviolet divergent geometric scalars. After the infrared divergences are absorbed into the quantum fluctuation, there remains the finite number of ultraviolet divergences. This implies that the D = p+2 Poincare symmetry and the D = p+1 general coordinate invariance are preserved in one-loop order.
African Journals Online (AJOL)
the inferior vena cava (Fig. 1). An interventional radiologist removed the guidewire via the femoral vein using a gooseneck snare. The patient recovered uneventfully. Discussion. Central venous access is an important strate- gy in the management of critically ill patients for CVP measurement, the infusion of drugs.
The universal one-loop effective action
Energy Technology Data Exchange (ETDEWEB)
Drozd, Aleksandra [Theoretical Particle Physics and Cosmology Group, Physics Department, King’s College London,Strand, London, WC2R 2LS (United Kingdom); Ellis, John [Theoretical Particle Physics and Cosmology Group, Physics Department, King’s College London,Strand, London, WC2R 2LS (United Kingdom); TH Division, Physics Department, CERN,Route de Meyrin, Geneva 23, CH-1211 (Switzerland); Quevillon, Jérémie [Theoretical Particle Physics and Cosmology Group, Physics Department, King’s College London,Strand, London, WC2R 2LS (United Kingdom); You, Tevong [Theoretical Particle Physics and Cosmology Group, Physics Department, King’s College London,Strand, London, WC2R 2LS (United Kingdom); Cavendish Laboratory, University of Cambridge,J.J. Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); DAMTP, University of Cambridge,Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
2016-03-25
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
The Universal One-Loop Effective Action
Drozd, Aleksandra; Quevillon, Jérémie; You, Tevong
2016-01-01
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
The universal one-loop effective action
Drozd, Aleksandra; Ellis, John; Quevillon, Jérémie; You, Tevong
2016-03-01
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
The universal one-loop effective action
International Nuclear Information System (INIS)
Drozd, Aleksandra; Ellis, John; Quevillon, Jérémie; You, Tevong
2016-01-01
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
String loop effect on the BRST charge
International Nuclear Information System (INIS)
Das, A.; Nishino, H.
1987-07-01
An effective BRST charge Q BRST which incorporates the string one-loop corrections is presented for the closed bosonic string in an arbitrary background. The effective σ-model action which leads to such a Q BRST is obtained and some consequences are discussed. (author). 14 refs, 1 fig
One-loop effective brane action
Lee, Tae-Hun
2007-01-01
The one-loop effective action for a $p$ brane embedded in a $D=p+2$ Minkowski spacetime in the static gauge is calculated. Rescaling the quantum fluctuation by $\\sqrt{-g_0}$ evaluated on the background brane leads to the one-loop effective action expressed only in terms of infrared and ultraviolet divergent geometric scalars. After the infrared divergences are absorbed into the quantum fluctuation, there remains the finite number of ultraviolet divergences. This implies that the $D=p+2$ Poinc...
Case Report: The story of a lost guidewire | Bagaria | Southern ...
African Journals Online (AJOL)
Seldinger's technique is widely used to place central venous and arterial catheters, and is generally considered to be safe. The technique does, however, have multiple potential risks. Guidewire-related complications are rare but potentially serious. We describe a case of a lost guidewire during central venous catheter ...
Heating and safety of a new MR-compatible guidewire prototype versus a standard nitinol guidewire.
Wolska-Krawczyk, Malgorzata; Rube, Martin A; Immel, Erwin; Melzer, Andreas; Buecker, Arno
2014-01-01
Our purpose in this study was to examine heating of nitinol and polyetheretherketone (PEEK) guidewires during near-real-time MR imaging in an artificial vascular model an "aorta phantom". The first 100 cm of the nitinol- and PEEK-based guidewires both 145 × 0.08 cm were immersed in a saline-filled aorta phantom. The probes of a fiber-optic thermometer were positioned at the tips of both wires. Balanced steady-state free precession (bSSFP) [TE 1.6 ms; TR 3.5 ms; flip angle (FA) 60°; field of view (FOV) 40 cm; matrix 256 × 256; specific absorption rate (SAR); 1.15 Watt (W)/kg] and spoiled gradient-echo (SPGR) (TE 1.8 ms; TR 60 ms; FA 60°; FOV 40 cm; matrix 256 × 256; SAR 1.15 W/kg) pulse sequences were acquired in a 1.5-T MR scanner with use of an 8-channel array coil. Temperatures were recorded while the phantom was placed centrally in the bore of a MR scanner and in an off-center position (x = 24 cm, y = -5 cm, z = -10/10 cm). The temperature of the nitinol guidewire increased by 0.3 °C (center) and 1.1 °C (off-center position) with use of the bSSFP and by 9.6 and 13 °C (off-center position) with use of the SPGR sequence. Only minor temperature changes up to a maximum of 0.4 °C were observed with the MR-compatible PEEK guidewire when any position or sequence was applied. The PEEK guidewire showed substantially lower heating as compared to the nitinol guidewire in near-real-time imaging sequences in a phantom.
One-loop effective lagrangians after matching
Energy Technology Data Exchange (ETDEWEB)
Aguila, F. del; Santiago, J. [Universidad de Granada, Departamento de Fisica Teorica y del Cosmos and CAFPE, Granada (Spain); Kunszt, Z. [ETH Zuerich, Institute for Theoretical Physics, Zuerich (Switzerland)
2016-05-15
We discuss the limitations of the covariant derivative expansion prescription advocated to compute the one-loop Standard Model (SM) effective lagrangian when the heavy fields couple linearly to the SM. In particular, one-loop contributions resulting from the exchange of both heavy and light fields must be explicitly taken into account through matching because the proposed functional approach alone does not account for them. We review a simple case with a heavy scalar singlet of charge -1 to illustrate the argument. As two other examples where this matching is needed and this functional method gives a vanishing result, up to renormalization of the heavy sector parameters, we re-evaluate the one-loop corrections to the T-parameter due to a heavy scalar triplet with vanishing hypercharge coupling to the Brout-Englert-Higgs boson and to a heavy vector-like quark singlet of charged 2/3 mixing with the top quark, respectively. In all cases we make use of a new code for matching fundamental and effective theories in models with arbitrary heavy field additions. (orig.)
Leptogenesis from loop effects in curved spacetime
Energy Technology Data Exchange (ETDEWEB)
McDonald, Jamie I.; Shore, Graham M. [Department of Physics, Swansea University,Singleton Park, Swansea, SA2 8PP (United Kingdom)
2016-04-05
We describe a new mechanism — radiatively-induced gravitational leptogenesis — for generating the matter-antimatter asymmetry of the Universe. We show how quantum loop effects in C and CP violating theories cause matter and antimatter to propagate differently in the presence of gravity, and prove this is forbidden in flat space by CPT and translation symmetry. This generates a curvature-dependent chemical potential for leptons, allowing a matter-antimatter asymmetry to be generated in thermal equilibrium in the early Universe. The time-dependent dynamics necessary for leptogenesis is provided by the interaction of the virtual self-energy cloud of the leptons with the expanding curved spacetime background, which violates the strong equivalence principle and allows a distinction between matter and antimatter. We show here how this mechanism is realised in a particular BSM theory, the see-saw model, where the quantum loops involve the heavy sterile neutrinos responsible for light neutrino masses. We demonstrate by explicit computation of the relevant two-loop Feynman diagrams how the size of the radiative corrections relevant for leptogenesis becomes enhanced by increasing the mass hierarchy of the sterile neutrinos, and show how the induced lepton asymmetry may be sufficiently large to play an important rôle in determining the baryon-to-photon ratio of the Universe.
Effect of vacancy loops on swelling of metals under irradiation
International Nuclear Information System (INIS)
Golubov, S.I.
1981-01-01
Subsequent analysis of vacancy loops formation in metals under irradiation is carried out and effect of vacancy loops on vacancy porosity is studied. Expression for quasistationary function of vacancy loops distribution according to sizes taking into consideration two mechanisms of their initiation-cascade and fluctuational ones - is obtained. It is shown that rate of vacancy absorption and interstitials by vacancy loops in quasiequilibrium state is similar and depends only on summary length of loops, for its calculations the self-coordinated procedure is formulated. For the rate of metal swelling under irradiation obtained is the expression taking into consideration the presence of vacancy loops [ru
Forces generated in guide-wires when drilling human bone.
Shuaib, I; Hillery, M
1995-01-01
In orthopaedic surgery guide-wires are extensively used for the drilling of pilot holes in human bones to allow further drilling, reaming and screw-tapping to take place in the repair and reconstruction of fractures. The guide-wires are generally 1.5 to 2.5 mm in diameter and have a three-faceted point with or without a screw thread. This paper describes drilling tests carried out using both types of guide-wire and these are compared with results obtained from a two-faceted geometry developed during this research. Tests were performed on the heads of femurs which had been removed during hip arthroplasty. A variable speed drilling machine together with a very sensitive drilling dynamometer were used for measuring the torque and thrust during the experimental stage of the research. This equipment was developed as part of an overall research programme into the mechanics of drilling of human bone. The indications are, firstly, that little advantage is gained by using a threaded-point guide-wire. In fact using a thread on the guide-wire can be a disadvantage. Secondly, the thrust cutting force is dependent on the spindle speed and feed. An optimum set of speeds of between 800 and 1400 r/min is recommended for 2.5 mm diameter guide-wires.
Peh, Wee Ming; Loh, Wann Jia; Phua, Ghee Chee; Loo, Chian Min
2016-01-01
Guidewire retention is a severe but preventable complication from central venous catheter (CVC) insertion. There were three cases of guidewire retention during CVC insertion in the medical intensive care unit (MICU) in Singapore General Hospital, in the period between December 2011 and February 2012. The primary objective of this quality improvement project was to eliminate future incidences of guidewire retention during CVC insertion in the MICU and medical intermediate care area (MICA) via a structured educational program and a cost effective modified CVC set. The secondary objective was to perform a cost analysis and comparison between the use of the conventional hospital CVC set and drape with our newly modified CVC dressing kit. Root cause analysis of the three cases identified major factors leading to guidewire retention. Interventions were planned and tested using PDSA cycles. Internal medicine trainees rotating through MICU and MICA during the period between February 2012 and June 2013 underwent a multi-modal structured CVC insertion training program with hands on simulation. They also used a newly modified CVC dressing kit and drape. The CVC dressing kit was modified (CVC PLUS) to include a sterile drape with reminder stickers stating "REMOVE the GUIDEWIRE," as well as a sterile ultrasound sleeve. The total number of CVC insertions performed and guidewire retentions were monitored. During the period of study there were 320 CVC insertions in the MICU and MICA. Since this quality improvement project was initiated, and up to the submission of this article, there have not been any further cases of guidewire retention in the MICU and MICA. The total cost reduction per use of CVC PLUS was S$29.26 (Singaporean Dollars). A multi-modal structured training program, integrated with a modified, pre-packed CVC set, and drapes with reminder stickers (all included in CVC PLUS) were cost effective, and improved patient safety by eliminating guidewire retention during CVC
International Nuclear Information System (INIS)
Krishnani, Mayur; Basu, Dipankar N.
2017-01-01
Highlights: • Computational model developed for single-phase rectangular natural circulation loop. • Role of loop inclination to vertical on thermalhydraulic stability is explored. • Inclination has strong stabilizing effect due to lower effective gravitation force. • Increase in tilt angle reduces settling time and highest amplitude of oscillation. • An angle of 15° is suggested for the selected loop geometry. - Abstract: Controlling stability behavior of single-phase natural circulation loops, without significantly affecting its steady-state characteristics, is a topic of wide research interest. Present study explores the role of loop inclination on a particular loop geometry. Accordingly a 3D computational model of a rectangular loop is developed and transient conservation equations are solved to obtain the temporal variation in flow parameters. Starting from the quiescent state, simulations are performed for selected sets of operating conditions and also with a few selected inclination angles. System experiences instability at higher heater powers and also with higher sink temperatures. Inclination is found to have a strong stabilizing influence owing to the reduction in the effective gravitational acceleration and subsequent decline in local buoyancy effects. The settling time and highest amplitude of oscillations substantially reduces for a stable system with a small inclination. Typically-unstable systems can also suppress the oscillations, when subjected to tilting, within a reasonable period of time. It is possible to stabilize the loop within shorter time span by increasing the tilt angle, but at the expense of reduction in steady-state flow rate. Overall a tilt angle of 15° is suggested for the selected geometry. Results from the 3D model is compared with the predictions from an indigenous 1D code. While similar qualitative influence of inclination is observed, the 1D model predicts early appearance of the stability threshold and hence hints
Energy Technology Data Exchange (ETDEWEB)
Lee, Seung Ryong; Baek, Kyong Hee; Jung, Gyoo Sik; Huh, Jin Do; Joh, Young Duk; Rim, Hark [Kosin Medical College, Pusan (Korea, Republic of)
1997-11-01
To determine the efficacy of correction of a malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance. Between November 1994 and March 1997, we performed 15 manipulations in 12 patients in whom a dual-cuff, straight Tenckhoff peritoneal dialysis catheter had been implanted due to chronic renal failure. The causes of catheter malfunctioning were inadequate drainage of the dialysate(n=14) and painful dialysis(n=1). Under fluoroscopic guidance, adhesiolysis and repositioning of the malfunctioning catheter were performed with an Amplatz Super Stiff guidewire and the stiffener from a biliary drainage catheter. The results of procedures were categorized as either immediate or durable success, this latter being defined as adequate catheter function for at least one month after the procedure. Immediate success was achieved in 14 of 15 procedures (93%), and durable success in 7 of 15(47%). The mean duration of catheter function was 157 (range, 30 to 578) days. After manipulation, abdominal pain developed in eight patients and peritonitis in two, but with conservative treatment, these symptoms improved. The correction of a malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance is an effective means of restoring catheter function and may be an effective alternative to surgical reimplantation of the catheter, or hemodialysis.
Outcome of emergency endovascular treatment of large internal iliac artery aneurysms with guidewires
International Nuclear Information System (INIS)
Cambj-Sapunar, Liana; Maskovic, Josip; Brkljacic, Boris; Radonic, Vedran; Dragicevic, Dragan; Ajduk, Marko
2010-01-01
Purpose: Guidewires have been reported as a useful occlusion material for large aneurysms of different locations with good short-term results. In this study we retrospectively evaluate long-term results of emergency embolization technique with guidewires in symptomatic internal iliac artery aneurysm (IIAA) impending rupture. Patients and methods: In four patients presented with acute abdominal pain, multidetector computed tomography revealed unstable, 7-14 cm large, IIAAs. Two patients were treated with coil embolization of distal branches followed by occlusion of aneurysmal sac with guidewires. In two patients embolization of aneurysmal sac alone was performed. Results: In three patients complete or near complete occlusion of the aneurysmal sac was achieved and abdominal pain ceased within hours. Two patients treated with embolization of distal iliac artery branches and aneurysmal sac developed claudication that lasted up to 1 year. Their aneurysms remained thrombosed and they were without symptoms until they died 31 and 56 months later of causes unrelated to IIAA. Two patients treated with embolization of the aneurysm alone were free of ischemic symptoms. Because of incomplete embolization of the sac in one patient open surgery treatment in a non-emergency setting was performed. Complete filling of aneurysmal sac was achieved in other patient but 2 years later his aneurysm re-opened and required open surgery treatment. Conclusion: Embolization of aneurysmal sac of large IIAA with guidewires may be effective for immediate treatment of impending rupture. Long-term results were better when embolization of the aneurysmal sac was combined with embolization of distal IIA branches.
On the one-loop effective potential in quantum gravity
International Nuclear Information System (INIS)
Yasuda, O.
1984-01-01
The one-loop effective potential is investigated in quantum gravity with or without cosmological constant in general D dimensions. It is shown that the partition function at the one-loop level depends only on the laplacian plus the scalar curvature with no terms of the form delta(0) ln g, i.e. Z (1-loop)=detsup(-1/2) (Δ 2 +2R/D)xdetsup(1/2) (Δsub(+)2R/D). An explicit calculation is carried out at the one-loop level to demonstrate gauge independence of the partition function in a class of general linear gauges. (orig.)
The Effects of Looping on Perceived Values and Academic Achievement
Rodriguez, Carmen; Arenz, Bernard
2007-01-01
This study was designed to examine the effects of looping, a practice whereby teachers and students stay together for more than one year, on perceived values and academic achievement in language arts at a Fresno Unified School District elementary school in Fresno, CA. Looping has many perceived advantages, such as the development of long-term…
International Nuclear Information System (INIS)
Fischer, Sebastian; Vogl, Thomas J.; Marzi, Ingo; Zangos, Stephan; Wichmann, Julian L.; Scholtz, Jan-Erik; Mack, Martin G.; Schmidt, Sven; Eichler, Katrin
2015-01-01
Highlights: • Minimally invasive sacroiliac screw fixation can be performed under CT-imaging. • Guidewires help in precise placement of cannulated sacroiliac screw. • Only a diminishing rate of misplacements can be seen. • The method appears to be a safe and very accurate procedure. - Abstract: Objective: The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. Methods: 100 guidewires and hollow titan screws were inserted in 38 patients (49.6 ± 19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. Results: The mean minimal distance between guidewire and adjacent neural foramina was 4.5 ± 2.01 mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6 ± 0.53 mm to 1.2 ± 0.54 mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5 mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0 min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7 mGy cm). Conclusions: The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels
Energy Technology Data Exchange (ETDEWEB)
Fischer, Sebastian, E-mail: sebastian.fischer@kgu.de [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Vogl, Thomas J. [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Marzi, Ingo [Department of Trauma, Hand and Reconstructive Surgery, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Zangos, Stephan; Wichmann, Julian L.; Scholtz, Jan-Erik; Mack, Martin G. [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Schmidt, Sven [Orthopaedic University Hospital Friedrichsheim, Marienburgstraße, 260528 Frankfurt (Germany); Eichler, Katrin [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany)
2015-02-15
Highlights: • Minimally invasive sacroiliac screw fixation can be performed under CT-imaging. • Guidewires help in precise placement of cannulated sacroiliac screw. • Only a diminishing rate of misplacements can be seen. • The method appears to be a safe and very accurate procedure. - Abstract: Objective: The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. Methods: 100 guidewires and hollow titan screws were inserted in 38 patients (49.6 ± 19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. Results: The mean minimal distance between guidewire and adjacent neural foramina was 4.5 ± 2.01 mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6 ± 0.53 mm to 1.2 ± 0.54 mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5 mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0 min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7 mGy cm). Conclusions: The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels.
Three-loop corrections in a covariant effective field theory
International Nuclear Information System (INIS)
McIntire, Jeff
2008-01-01
Chiral effective field theories have been used with success in the study of nuclear structure. It is of interest to systematically improve these energy functionals (particularly that of quantum hadrodynamics) through the inclusion of many-body correlations. One possible source of improvement is the loop expansion. Using the techniques of Infrared Regularization, the short-range, local dynamics at each order in the loops is absorbed into the parameterization of the underlying effective Lagrangian. The remaining nonlocal, exchange correlations must be calculated explicitly. Given that the interactions of quantum hadrodynamics are relatively soft, the loop expansion may be manageable or even perturbative in nuclear matter. This work investigates the role played by the three-loop contributions to the loop expansion for quantum hadrodynamics
One-loop effective potential from compactified superstring models
International Nuclear Information System (INIS)
Gaillard, M.K.
1985-10-01
A recent determination is reported of the one loop effective potential from the effective tree Lagrangian in models obtained from compactification of the zero-slope limit of superstring theories, both with and without induced terms conjectured to arise from nonperturbative effects in a hidden sector theory. In the absence of condensate effects, the vacuum structure of the tree potential is preserved by the one-loop radiative corrections. In the presence of supersymmetry breaking condensate effects at tree level, the gauge non-singlet scalars remain massless at the one-loop level. In this case the vacuum expectation value of Re t and therefore the gravitino mass are determined at one loop. Specifically, it is found that the gravitino mass, the condensate scale, and the grand unification scale must all lie within a few orders of the Planck scale. 14 refs
Miniaturized Optical Data Link Assembly for 360 um Guidewires
Stoute, R.; Louwerse, M.C.; Van Rens, J.; Henneken, V.A.; Dekker, R.
2015-01-01
We propose a novel concept for a high-speed optical data link in Ø 360 µm cardiovascular interventional imaging guidewires. The concept is based on the recently introduced Flex-to-Rigid (F2R) technology platform. This technology allows for smaller intravascular imaging devices with a more compact
One-loop effective potential on hyperbolic manifolds
International Nuclear Information System (INIS)
Cognola, G.; Kirsten, K.; Zerbini, S.
1993-01-01
The one-loop effective potential for a scalar field defined on an ultrastatic space-time whose spatial part is a compact hyperbolic manifold is studied using ζ-function regularization for the one-loop effective action. Other possible regularizations are discussed in detail. The renormalization group equations are derived, and their connection with the conformal anomaly is pointed out. The symmetry breaking and the topological mass generation are also discussed
The Role of Entropic Effects on DNA Loop Formation
Wilson, David; Tkachenko, Alexei; Lillian, Todd; Perkins, Noel; Meiners, Jens Christian
2009-03-01
The formation of protein mediated DNA loops often regulates gene expression. Typically, a protein is simultaneously bound to two DNA operator sites. An example is the lactose repressor which binds to the Lac operon of E. coli. We characterize the mechanics of this system by calculating the free energy cost of loop formation. We construct a Hamiltonian that describes the change in DNA bending energy due to linear perturbations about the looped and open states, starting from a non-linear mechanical rod model that determines the shape and bending energy of the inter-operator DNA loop while capturing the intrinsic curvature and sequence-dependent elasticity of the DNA. The crystal structure of the LacI protein provides the boundary conditions for the DNA. We then calculate normal modes of the open and closed loops to account for the thermal fluctuations. The ratio of determinants of the two Hamiltonians yields the partition function, and the enthalphic and entropic cost of looping. This calculation goes beyond standard elastic energy models because it fully accounts for the substantial entropic differences between the two states. It also includes effects of sequence dependent curvature and stiffness and allows anisotropic variations in persistence length. From the free energy we then calculate the J-factor and ratio of loop lifetimes.
Loop-Effects in Pseudo-Supersymmetry
Energy Technology Data Exchange (ETDEWEB)
Klein, Matthias
2002-11-01
We analyze the transmission of supersymmetry breaking in brane-world models of pseudo-supersymmetry. In these models two branes preserve different halves of the bulk supersymmetry. Thus supersymmetry is broken although each sector of the model is supersymmetric when considered separately. The world-volume theory on one brane feels the breakdown of supersymmetry only through two-loop interactions involving a coupling to fields from the other brane. In a 5D toy model with bulk vectors, we compute the diagrams that contribute to scalar masses on one brane and find that the masses are proportional to the compactification scale up to logarithmic corrections, m{sup 2} {infinity} (2{pi}R){sup -2} (ln(2{pi}R m{sub S}) - 1.1), where m{sub s} is an ultraviolet cutoff. Thus, for large compactification radii, where this result is valid, the brane scalars acquire a positive mass squared. We also compute the three-loop diagrams relevant to the Casimir energy between the two branes and find E {infinity} (2{pi}R){sup -4}((ln(2{pi}R m{sub S}) - 1.7){sup 2} + 0.2). For large radii, this yields a repulsive Casimir force.
Doorey, Andrew J; Gakhal, Mandip; Pasquale, Michael J
2006-04-01
Suspected prosthetic valve dysfunction is a difficult clinical problem, because of the high risk of repeat valvular surgery. Echocardiographic measurements of prosthetic valvular dysfunction can be misleading, especially with bileaflet valves. Direct measurement of trans-valvular gradients is problematic because of potentially serious catheter entrapment issues. We report a case in which a high-fidelity pressure sensor angioplasty guidewire was used to cross prosthetic mitral and aortic valves in a patient, with hemodynamic and echocardiographic assessment. This technique was safe and effective, refuting the inaccurate non-invasive tests that over-estimated the aortic valvular gradient.
Effective field theory of precision electroweak physics at one loop
International Nuclear Information System (INIS)
Mebane, Harrison; Greiner, Nicolas; Zhang, Cen; Willenbrock, Scott
2013-01-01
The one loop effects of two dimension-six operators on gauge boson self-energies are computed within an effective field theory framework. These self-energies are translated into effects on precision electroweak observables, and bounds are obtained on the operator coefficients. The effective field theory framework allows for the divergences that arise in the loop calculations to be properly handled, and for unambiguous bounds on the coefficients to be obtained. We find that the coefficients are only weakly bounded, in contrast to previous calculations that obtained much stronger bounds. We argue that the results of these previous calculations are specious
Remote Manipulation of Guidewire using a Virtual Reality Device.
Fukasaku, K; Negoro, M; Himeno, R
2001-12-22
A trial of remote manipulation for micro guidewire is reported. The system had masterslave style. When an operator manipulated the virtual torque device at the master side, a machine at the distant slave side reproduced the manipulation. At the same time, the operator could feel the force feedback from the manipulation at the slave. We could experimentally realize this remote manipulating system using a virtual reality device.
Remote Manipulation of Guidewire using a Virtual Reality Device
Fukasaku, K.; Negoro, M.; Himeno, R.
2001-01-01
A trial of remote manipulation for micro guidewire is reported. The system had master-slave style. When an operator manipulated the virtual torque device at the master side, a machine at the distant slave side reproduced the manipulation. At the same time, the operator could feel the force feedback from the manipulation at the slave. We could experimentally realize this remote manipulating system using a virtual reality device.
Energy Technology Data Exchange (ETDEWEB)
Nam, Jeong Gu; Seo, Young Woo; Hwang, Jae Cheol; Weon, Young Cheol; Kang, Byeong Seong; Bang, Sung Jo; Bang, Min Seo [Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan (Korea, Republic of)
2015-05-15
Although endoscopic retrograde cholangiopancreatography (ERCP) is an effective modality for diagnosis and treatment of biliary and pancreatic diseases, the risk for procedure-related complications is high. Hemorrhage is one of major complications of ERCP. Most ERCP-associated bleeding is primarily a complication related to sphincterotomy rather than diagnostic ERCP. We are reporting a case of massive hemobilia due to hepatic arteriobiliary fistula caused by guidewire-associated injury during ERCP, which was successfully treated with transarterial embolization of the hepatic artery.
Olsen, Michael; Chiu, Mark; Gamble, Patrick; Boyle, Richard A; Tumia, Nezar; Schemitsch, Emil H
2010-08-04
Correct positioning of the initial femoral guidewire is vital in order to prepare the femoral head properly for hip resurfacing. The purpose of the present investigation was to determine the accuracy and precision of the placement of the initial femoral guidewire with use of conventional alignment jigs and to compare the results with those of imageless computer navigation. Five commercially available jigs (two lateral pin jigs, two neck centering jigs, and one head planing jig) were obtained. Four surgeons used each jig and navigation three times to insert a guidewire in 10 degrees of relative valgus and neutral version into individual synthetic femora. A single surgeon then used each jig three times to align the initial guidewire in 10 degrees of relative valgus and neutral version in each of ten human cadaver femora. Radiographs of the synthetic and human femora were made to assess and compare guidewire inclination and version between conventional instrumentation and navigation. Navigation provided ranges of error in the coronal guidewire alignment of up to eight times less than the conventional jigs, but both methods provided similar ranges of error for version. In both arms of the study, there were significant differences in coronal alignment accuracy between the two neck centering jigs. Next to navigation, one lateral pin jig provided the most accurate coronal placement of the initial guidewire whereas one neck centering jig provided the most precise coronal placement of the guidewire. Navigation was similar to conventional jigs in terms of the accuracy and precision of guidewire version. In hip resurfacing arthroplasty, the choice of a femoral alignment device may influence the accuracy and precision of guidewire insertion, ultimately impacting femoral component placement. Imageless computer navigation can facilitate accurate and precise coronal alignment of the initial femoral guidewire, superior to that of conventional instrumentation. The results of this
On the Convergence in Effective Loop Quantum Cosmology
International Nuclear Information System (INIS)
Corichi, Alejandro; Vukasinac, Tatjana; Zapata, Jose Antonio
2010-01-01
In Loop Quantum Cosmology (LQC) there is a discreteness parameter λ, that has been heuristically associated to a fundamental granularity of quantum geometry. It is also possible to consider λ as a regulator in the same spirit as that used in lattice field theory, where it specifies a regular lattice in the real line. A particular quantization of the k = 0 FLRW loop cosmological model yields a completely solvable model, known as solvable loop quantum cosmology(sLQC). In this contribution, we consider effective classical theories motivated by sLQC and study their λ-dependence, with a special interest on the limit λ→0 and the role of the evolution parameter in the convergence of such limit.
Twisted-baryon-loop effects in dual topological unitarization
Energy Technology Data Exchange (ETDEWEB)
Gauron, P.; Nicolescu, B.; Ouvry, S.; Uschersohn, J.
1981-05-01
Within the framework of dual topological unitarization we propose a simple model for mesons, baryons, and baryonium which allows us to calculate the effects of inserting nonplanar BB-bar loops in all possible ways into meson and baryonium propagators. We study the renormalization of the leading nonzero-isospin trajectories and the mixing of qq-bar and qqq-barq-bar states.
String loop divergences and effective lagrangians
International Nuclear Information System (INIS)
Fischler, W.; Klebanov, I.; Susskind, L.
1988-01-01
We isolate logarithmic divergences from bosonic string amplitudes on a disc. These divergences are compared with 'tadpole' divergences in the effective field theory, with a covariant cosmological term implied by the counting of string coupling constants. We find an inconsistency between the two. This might be a problem in eliminating divergences from the bosonic string. (orig.)
Effective nonrenormalizable theories at one loop
Energy Technology Data Exchange (ETDEWEB)
Gaillard, M.K.
1987-10-12
The paper focuses on a nonrenormalizable theory that is more closely related to those suggested by superstrings, namely a gauged nonlinear delta-model, but one which can also be obtained analytically in a particular limit of a parameter (m/sub H/ ..-->.. infinity) of the standard, renormalizable electroweak theory. This will provide another laboratory for testing the validity of calculations using the effective theory. We find (as for certain superstring inspired models to be discussed later) features similar to those for the Fermi theory: quadratic divergences can be reinterpreted as renormalizations, while new terms are generated at the level of logarithmic divergences. Also introduced in the context of more familiar physics are notions such as scalar metric, scalar curvature and nonlinear symmetries, that play an important role in formal aspects of string theories. 58 refs., 12 figs.
Effective nonrenormalizable theories at one loop
International Nuclear Information System (INIS)
Gaillard, M.K.
1987-01-01
The paper focuses on a nonrenormalizable theory that is more closely related to those suggested by superstrings, namely a gauged nonlinear δ-model, but one which can also be obtained analytically in a particular limit of a parameter (m/sub H/ → ∞) of the standard, renormalizable electroweak theory. This will provide another laboratory for testing the validity of calculations using the effective theory. We find (as for certain superstring inspired models to be discussed later) features similar to those for the Fermi theory: quadratic divergences can be reinterpreted as renormalizations, while new terms are generated at the level of logarithmic divergences. Also introduced in the context of more familiar physics are notions such as scalar metric, scalar curvature and nonlinear symmetries, that play an important role in formal aspects of string theories. 58 refs., 12 figs
Khalili, Houman; Vo, Minh N; Brilakis, Emmanouil S
2016-02-01
Inability to cross the occlusion with a guidewire is the most common cause of failure of coronary chronic total occlusion (CTO) interventions. We describe two cases of successful application of the novel Gaia family of coronary guidewires (Asahi Intecc) for crossing coronary CTOs using all available crossing strategies, namely antegrade wire escalation, antegrade dissection/reentry, and retrograde.
High maneuverability guidewire with functionally graded properties using new superelastic alloys.
Sutou, Y; Yamauchi, K; Suzuki, M; Furukawa, A; Omori, T; Takagi, T; Kainuma, R; Nishida, M; Ishida, K
2006-01-01
Nitinol shape memory alloys (SMAs) are attracting considerable attention as core materials for medical guidewires because of their excellent flexibility and shape retention. However, since Nitinol guidewires possess low rigidity, the pushability and torquability of the guidewires are insufficient. On the other hand, although guidewires made of stainless steel have high pushability, plastic deformation occurs easily. We have developed a new class of superelastic guidewires with functionally graded properties from the tip to the end by using new SMA core materials such as Cu-Al-Mn-based or Ni-free Ti-Mo-Sn SMAs. The tip portion of the guidewire shows excellent superelasticity (SE), while the body portion possesses high rigidity. These functionally graded characteristics can be realized by microstructural control. These guidewires with functionally graded properties show excellent pushability and torquability and are considerably easier to handle than conventional guidewires with Nitinol or stainless steel cores. Moreover, a metallic catheter using a Ni-free Ti-based SMA with high biocompatibility is introduced.
One-loop effective actions and higher spins
Bonora, L.; Cvitan, M.; Prester, P. Dominis; Giaccari, S.; de Souza, B. Lima; Štemberga, T.
2016-12-01
The idea we advocate in this paper is that the one-loop effective action of a free (massive) field theory coupled to external sources (via conserved currents) contains complete information about the classical dynamics of such sources. We show many explicit examples of this fact for (scalar and fermion) free field theories in various dimensions d = 3 ,4 ,5 ,6 coupled to (bosonic, completely symmetric) sources with a number of spins. In some cases we also provide compact formulas for any dimension. This paper is devoted to two-point correlators, so the one-loop effective action we construct contains only the quadratic terms and the relevant equations of motion for the sources we obtain are the linearized ones.
One-loop effective actions and higher spins
Energy Technology Data Exchange (ETDEWEB)
Bonora, L. [International School for Advanced Studies (SISSA),Via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste,Trieste (Italy); Cvitan, M. [Theoretical Physics Division of Particles and Fields, Faculty of Science, University of Zagreb,Bijenička 32, HR-10000 Zagreb (Croatia); Prester, P. Dominis [Department of Physics, University of Rijeka,Radmile Matejčić 2, 51000 Rijeka (Croatia); Giaccari, S. [Theoretical Physics Division of Particles and Fields, Faculty of Science, University of Zagreb,Bijenička 32, HR-10000 Zagreb (Croatia); Souza, B. Lima de [International School for Advanced Studies (SISSA),Via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste,Trieste (Italy); Štemberga, T. [Theoretical Physics Division of Particles and Fields, Faculty of Science, University of Zagreb,Bijenička 32, HR-10000 Zagreb (Croatia)
2016-12-16
The idea we advocate in this paper is that the one-loop effective action of a free (massive) field theory coupled to external sources (via conserved currents) contains complete information about the classical dynamics of such sources. We show many explicit examples of this fact for (scalar and fermion) free field theories in various dimensions d=3,4,5,6 coupled to (bosonic, completely symmetric) sources with a number of spins. In some cases we also provide compact formulas for any dimension. This paper is devoted to two-point correlators, so the one-loop effective action we construct contains only the quadratic terms and the relevant equations of motion for the sources we obtain are the linearized ones.
One-loop effective action and the Riemann zeros
Dueñas, J. G.; Svaiter, N. F.; Menezes, G.
2014-12-01
We present a remarkable connection between the asymptotic behavior of the Riemann zeros and one-loop effective action in Euclidean scalar field theory. We show that in a two-dimensional space, the asymptotic behavior of the Fourier transform of two-point correlation functions fits the asymptotic distribution of the nontrivial zeros of the Riemann zeta function. We work out an explicit example, namely the nonlinear sigma model in the leading order in 1/N expansion.
Thermal phase transition with full 2-loop effective potential
Laine, M.; Meyer, M.; Nardini, G.
2017-07-01
Theories with extended Higgs sectors constructed in view of cosmological ramifications (gravitational wave signal, baryogenesis, dark matter) are often faced with conflicting requirements for their couplings; in particular those influencing the strength of a phase transition may be large. Large couplings compromise perturbative studies, as well as the high-temperature expansion that is invoked in dimensionally reduced lattice investigations. With the example of the inert doublet extension of the Standard Model (IDM), we show how a resummed 2-loop effective potential can be computed without a high-T expansion, and use the result to scrutinize its accuracy. With the exception of Tc, which is sensitive to contributions from heavy modes, the high-T expansion is found to perform well. 2-loop corrections weaken the transition in IDM, but they are moderate, whereby a strong transition remains an option.
Thermal phase transition with full 2-loop effective potential
Directory of Open Access Journals (Sweden)
M. Laine
2017-07-01
Full Text Available Theories with extended Higgs sectors constructed in view of cosmological ramifications (gravitational wave signal, baryogenesis, dark matter are often faced with conflicting requirements for their couplings; in particular those influencing the strength of a phase transition may be large. Large couplings compromise perturbative studies, as well as the high-temperature expansion that is invoked in dimensionally reduced lattice investigations. With the example of the inert doublet extension of the Standard Model (IDM, we show how a resummed 2-loop effective potential can be computed without a high-T expansion, and use the result to scrutinize its accuracy. With the exception of Tc, which is sensitive to contributions from heavy modes, the high-T expansion is found to perform well. 2-loop corrections weaken the transition in IDM, but they are moderate, whereby a strong transition remains an option.
One-Loop Effective Action in Orbifold Compactifications
Von Gersdorff, Gero
2008-01-01
We employ the covariant background formalism to derive generic expressions for the one-loop effective action in field theoretic orbifold compactifications. The contribution of each orbifold sector is given by the effective action of its fixed torus with a shifted mass matrix. We thus study in detail the computation of the heat kernel on tori. Our formalism manifestly separates UV sensitive (local) from UV-insensitive (nonlocal) renormalization. To exemplify our methods, we study the effective potential of 6d gauge theory as well as kinetic terms for gravitational moduli in 11d supergravity.
One-loop effective action in quantum gravitation
DEFF Research Database (Denmark)
Rachwal, Leslaw; Codello, Alessandro; Percacci, Roberto
2016-01-01
We present the formalism of computing one-loop effective action for Quantum Gravitation using non-local heat kernel methods. We found agreement with previous old results. In main part of my presentation I considered the system of E-H gravitation and scalar fields. We were able to derive non......-local quantum effective action up to the second order in heat kernel generalized curvatures. By going to flat spacetime expressions for gravitational form factors are possible to construct and compare with the results from effective field theory for gravity....
Yun, Cheol-Ho; Yeo, Leslie Y.; Friend, James R.; Yan, Bernard
2012-04-01
A 240-μm diameter ultrasonic micromotor is presented as a potential solution for an especially difficult task in minimally invasive neurosurgery, navigating a guidewire to an injury in the neurovasculature as the first step of surgery. The peak no-load angular velocity and maximum torque were 600 rad/s and 1.6 nN-m, respectively, and we obtained rotation about all three axes. By using a burst drive scheme, open-loop position and speed control were achieved. The construction method and control scheme proposed in this study remove most of the current limitations in minimally invasive, catheter-based actuation, enabling minimally invasive vascular surgery concepts to be pursued for a broad variety of applications.
Effects of gender and recall types on memory loops of working ...
African Journals Online (AJOL)
. However, significant differences existed between recall types on memory loops, and interaction effect was found to exist between the two independent variables. It was recommended that male edlerlies be exposed more on S + V loops while ...
Loop quantum cosmology of Bianchi IX: effective dynamics
Corichi, Alejandro; Montoya, Edison
2017-03-01
We study solutions to the effective equations for the Bianchi IX class of spacetimes within loop quantum cosmology (LQC). We consider Bianchi IX models whose matter content is a massless scalar field, by numerically solving the loop quantum cosmology effective equations, with and without inverse triad corrections. The solutions are classified using certain geometrically motivated classical observables. We show that both effective theories—with lapse N = V and N = 1—resolve the big bang singularity and reproduce the classical dynamics far from the bounce. Moreover, due to the positive spatial curvature, there is an infinite number of bounces and recollapses. We study the limit of large field momentum and show that both effective theories reproduce the same dynamics, thus recovering general relativity. We implement a procedure to identify amongst the Bianchi IX solutions, those that behave like k = 0,1 FLRW as well as Bianchi I, II, and VII0 models. The effective solutions exhibit Bianchi I phases with Bianchi II transitions and also Bianchi VII0 phases, which had not been studied before. We comment on the possible implications of these results for a quantum modification to the classical BKL behaviour.
Loop quantum cosmology of Bianchi IX: effective dynamics
International Nuclear Information System (INIS)
Corichi, Alejandro; Montoya, Edison
2017-01-01
We study solutions to the effective equations for the Bianchi IX class of spacetimes within loop quantum cosmology (LQC). We consider Bianchi IX models whose matter content is a massless scalar field, by numerically solving the loop quantum cosmology effective equations, with and without inverse triad corrections. The solutions are classified using certain geometrically motivated classical observables. We show that both effective theories—with lapse N = V and N = 1—resolve the big bang singularity and reproduce the classical dynamics far from the bounce. Moreover, due to the positive spatial curvature, there is an infinite number of bounces and recollapses. We study the limit of large field momentum and show that both effective theories reproduce the same dynamics, thus recovering general relativity. We implement a procedure to identify amongst the Bianchi IX solutions, those that behave like k = 0,1 FLRW as well as Bianchi I, II, and VII 0 models. The effective solutions exhibit Bianchi I phases with Bianchi II transitions and also Bianchi VII 0 phases, which had not been studied before. We comment on the possible implications of these results for a quantum modification to the classical BKL behaviour. (paper)
Magnetic versus manual guidewire manipulation in neuroradiology: in vitro results.
Krings, T; Finney, J; Niggemann, P; Reinacher, P; Lück, N; Drexler, A; Lovell, J; Meyer, A; Sehra, R; Schauerte, P; Reinges, M; Hans, F J; Thron, A
2006-06-01
Standard microguidewires used in interventional neuroradiology have a predefined shape of the tip that cannot be changed while the guidewire is in the vessel. We evaluated a novel magnetic navigation system (MNS) that generates a magnetic field to control the deflection of a microguidewire that can be used to reshape the guidewire tip in vivo without removing the wire from the body, thereby potentially facilitating navigation along tortuous paths or multiple acute curves. The MNS consists of two permanent magnets positioned on either side of the fluoroscopy table that create a constant precisely controlled magnetic field in the defined region of interest. This field enables omnidirectional rotation of a 0.014-inch magnetic microguidewire (MG). Speed of navigation, accuracy in a tortuous vessel anatomy and the potential for navigating into in vitro aneurysms were tested by four investigators with differing experience in neurointervention and compared to navigation with a standard, manually controlled microguidewire (SG). Navigation using MG was faster (P=0.0056) and more accurate (0.2 mistakes per trial vs. 2.6 mistakes per trial) only in less-experienced investigators. There were no statistically significant differences between the MG and the SG in the hands of experienced investigators. One aneurysm with an acute angulation from the carrier vessel could be navigated only with the MG while the SG failed, even after multiple reshaping manoeuvres. Our findings suggest that magnetic navigation seems to be easier, more accurate and faster in the hands of less-experienced investigators. We consider that the features of the MNS may improve the efficacy and safety of challenging neurointerventional procedures.
Secular effects on inflation from one-loop quantum gravity
International Nuclear Information System (INIS)
Cabrer, J.A.; Espriu, D.
2008-01-01
In this Letter we revisit and extend a previous analysis where the possible relevance of quantum gravity effects in a cosmological setup was studied. The object of interest are non-local (logarithmic) terms generated in the effective action of gravity due to the exchange in loops of massless modes (such as photons or the gravitons themselves). We correct one mistake existing in the previous work and discuss the issue in a more general setting in different cosmological scenarios. We obtain the one-loop quantum-corrected evolution equations for the cosmological scale factor up to a given order in a derivative expansion in two particular cases: a matter dominated universe with vanishing cosmological constant, and in a de Sitter universe. We show that the quantum corrections, albeit tiny, may have a secular effect that eventually modifies the expansion rate. For a de Sitter universe they tend to slow down the rate of the expansion, while the effect may be the opposite in a matter dominated universe
Gravitational interaction to one loop in effective quantum gravity
International Nuclear Information System (INIS)
Akhundov, A.
1996-10-01
The authors carry out the first step of a program conceived, in order to build a realistic model, having the particle spectrum of the standard model and renormalized masses, interaction terms and coupling, etc. which include the class of quantum gravity corrections, obtained by handling gravity as an effective theory. This provides an adequate picture at low energies, i.e. much less than the scale of strong gravity (the Planck mass). Hence the results are valid, irrespectively of any proposal for the full quantum gravity as a fundamental theory. The authors consider only non-analytic contributions to the one-loop scattering matrix elements, which provide the dominant quantum effect at long distance. These contributions are finite and independent from the finite value of the renormalization counter terms of the effective Lagrangian. The authors calculate the interaction of two heavy scalar particles, i.e. close to rest, due to the effective quantum gravity to the one loop order and compare with similar results in the literature
Effect of sub-loops in SMA ear system
Mitura, Andrzej; Rusinek, Rafał
2018-01-01
The main aim of this paper is modelling the hysteresis effect in shape memory alloys. The stress versus strain relation is approximated by idealized curves. The adopted characteristics is modelled using the piecewise linear model. Transmission between individual line segments is dependent on the proposed conditions if(…). Performed numerical research allows to evaluate the possibilities of hysteresis sub-loops modelling. Finally, this model is used in a specific system - the biomechanical model of the middle ear to find the reconstructed ear response.
Generalised zeta-function regularization for scalar one-loop effective action
Cognola, Guido; Zerbini, Sergio
2004-01-01
The one-loop effective action for a scalar field defined in the ultrastatic space-time where non standard logarithmic terms in the asymptotic heat-kernel expansion are present, is investigated by a generalisation of zeta-function regularisation. It is shown that additional divergences may appear at one-loop level. The one-loop renormalisability of the model is discussed and the one-loop renormalisation group equations are derived.
Covariant effective action for loop quantum cosmology from order reduction
International Nuclear Information System (INIS)
Sotiriou, Thomas P.
2009-01-01
Loop quantum cosmology (LQC) seems to be predicting modified effective Friedmann equations without extra degrees of freedom. A puzzle arises if one decides to seek for a covariant effective action which would lead to the given Friedmann equation: The Einstein-Hilbert action is the only action that leads to second order field equations and, hence, there exists no covariant action which, under metric variation, leads to a modified Friedmann equation without extra degrees of freedom. It is shown that, at least for isotropic models in LQC, this issue is naturally resolved and a covariant effective action can be found if one considers higher order theories of gravity but faithfully follows effective field theory techniques. However, our analysis also raises doubts on whether a covariant description without background structures can be found for anisotropic models.
Patient-specific simulation of guidewire deformation during transcatheter aortic valve implantation.
Vy, Phuoc; Auffret, Vincent; Castro, Miguel; Badel, Pierre; Rochette, Michel; Haigron, Pascal; Avril, Stéphane
2018-02-27
Transcatheter aortic valve implantation is a recent mini-invasive procedure to implant an aortic valve prosthesis. Prosthesis positioning in transcatheter aortic valve implantation appears as an important aspect for the success of the intervention. Accordingly, we developed a patient-specific finite element framework to predict the insertion of the stiff guidewire, used to position the aortic valve. We simulated the guidewire insertion for 2 patients based on their pre-operative CT scans. The model was designed to primarily predict the position and the angle of the guidewires in the aortic valve, and the results were successfully compared with intraoperative images. The present paper describes extensively the numerical model, which was solved by using the ANSYS software with an implicit resolution scheme, as well as the stabilization techniques which were used to overcome numerical instabilities. We performed sensitivity analysis on the properties of the guidewire (curvature angle, curvature radius, and stiffness) and the conditions of insertion (insertion force and orientation). We also explored the influence of the model parameters. The accuracy of the model was quantitatively evaluated as the distance and the angle difference between the simulated guidewires and the intraoperative ones. A good agreement was obtained between the model predictions and intraoperative views available for 2 patient cases. In conclusion, we showed that the shape of the guidewire in the aortic valve was mainly determined by the geometry of the patient's aorta and by the conditions of insertion (insertion force and orientation). Copyright © 2018 John Wiley & Sons, Ltd.
One-loop effective potential in nonlocal supersymmetric theories
de Mello, E. R. Bezerra; Gama, F. S.; Nascimento, J. R.; Petrov, A. Yu.
2017-01-01
Within the superfield approach, we consider the nonlocal generalization of the Wess-Zumino model and calculate the one-loop low-energy contributions to the effective action. Four different nonlocal models are considered, among which only the first model does not reduce to the standard Wess-Zumino model when we take the parameter of nonlocality of the model, Λ , much greater than any energy scale; in addition, this model also depends on an extra parameter ξ . As to the other three models, the result looks like the renormalized effective potential for the usual Wess-Zumino model, where the normalization scale μ is replaced by the Λ . Moreover, the fourth model displays a divergence which can be eliminated through the appropriate wave function renormalization.
Remarks on meson loop effects on quark models
Energy Technology Data Exchange (ETDEWEB)
Hammer, I.K.; Hanhart, C. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich (Germany); Nefediev, A.V. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); National Research Nuclear University MEPhI, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region (Russian Federation)
2016-11-15
We investigate the effect of meson loops on the spectrum of quark states. We demonstrate that in general quark states do not tend to get very broad if their coupling to the continuum increases, but instead they decouple from the latter in the large coupling limit. We ascribe this effect to the essentially nonperturbative unitarization procedure involved. In the meantime, some quark resonances behave very differently and demonstrate collectivity in the sense that their pole trajectories span a wide, as compared to the level spacing, region therefore acquiring contributions from multiple bare poles rather than from the closest neighbors. While the actual calculations are done within particular, very simplified models, it is argued that the findings might well be general. (orig.)
Robust guidewire tracking under large deformations combining segment-like features (SEGlets).
Vandini, Alessandro; Glocker, Ben; Hamady, Mohamad; Yang, Guang-Zhong
2017-05-01
Robust tracking of interventional tools, such as guidewires and catheters, in X-ray fluoroscopic video sequences has a wide range of clinical applications for endovascular procedures. Thus far, the tracking is usually achieved by finding the optimal displacement of the control points of a spline, which models the guidewire, between consecutive frames. The displacement of the control points is typically driven by a data term and smoothed by a regularization term. In the presence of large deformation and changes in length of the tool, the current tracking methods may fail to recover the guidewire motion. This can occur because of the limitation of the data and regularization terms, and the absence of an explicit solution for coping with elongations of the guidewire. The purpose of this paper is to present an algorithm that can robustly track guidewires under these challenging conditions. The algorithm is based on two main contributions: (a) new robust features termed SEGlets for segment-like features are introduced to overcome the limitations of the current data terms; (b) a tracking formulation based on the generation of tracking hypotheses by organizing the SEGlets in plausible guidewire shapes. The proposed method allows high flexibility of the guidewire between consecutive frames in contrast to the spline model, which can suffer from the limitations of the regularization terms. Furthermore, the technique models elongations of the guidewire which makes it possible for robust tracking under motion. A tool model which is recursively updated by employing a Kalman filter, is also proposed for modelling the regularization term. A detailed evaluation and a comparative study with three state-of-the-art guidewire tracking methods have been performed to demonstrate the potential clinical value of the technique. The proposed method achieves an overall guidewire tracking precision of 2.40 pixels, tip precision of 25.55 pixels, false tracking rate of 5.73%, missing
Oishi, Yoshihiko; Okamoto, Mitsunori; Sueda, Takashi; Hashimoto, Masaki; Karakawa, Shinji; Kambe, Masayuki
2002-07-01
The effect of guidewire bias on angled-lesion ablation by rotational atherectomy (RA) was assessed by measuring the changes in vertical lumen diameter, horizontal lumen diameter and the intima-media thickness of the coronary artery, using intravascular ultrasound in 10 lesions with an angle greater than 10 degrees. The vertical and horizontal diameters significantly increased after RA. The intima-media thickness at the 4 orthogonal sites significantly decreased. There was a significant positive correlation between vertical diameter change and angle (r=0.642, p=0.045), but none between horizontal diameter change and angle. There was no correlation between intima-media thickness change at 0 degrees and angle; however, at 180 degrees there was a tendency to correlation with angle (r=0.602, p=0.066). These data suggest that in cases of angled lesions, the increase in vertical lumen diameter is caused more by ablation of the 180 degrees wall than by that of the 0 degrees wall, which is brought about by guidewire bias toward the vascular wall at 180 degrees.
Quarkonium spectroscopy and perturbative QCD massive quark-loop effects
Brambilla, Nora; Vairo, Antonio
2002-01-01
We study the spectra of the bottomonium and B_c states within perturbative QCD up to order alpha_s^4. The O(Lambda_QCD) renormalon cancellation between the static potential and the pole mass is performed in the epsilon-expansion scheme. We extend our previous analysis by including the effects of non-zero charm-quark mass in loops up to the next-to-leading non-vanishing order epsilon^3. An extensive quantitative analysis is provided. Qualitatively the effect of the charm mass is to widen the level spacings and the effect becomes larger among higher levels. The size of non-perturbative and higher order contributions is discussed by comparing the obtained predictions with the experimental data. An agreement of the perturbative predictions and the experimental data depends crucially on the precise value (inside the present error) of alpha_s(M_Z). For the b-quark MSbar mass we obtain $m_b^{\\overline{MS}}(m_b^{\\overline{MS}}) = 4190 \\pm 20 \\pm 25 \\pm 4 ~ {MeV}$.
Energy Technology Data Exchange (ETDEWEB)
Gao, Ning; Shen, Tielong; Kurtz, Richard; Wang, Zhiguang; Gao, Fei
2017-07-01
The properties of nano-scale interstitial dislocation loops under the coupling effect of stress and temperature are studied using atomistic simulation methods and experiments. The decomposition of a loop by the emission of smaller loops is identified as one of the major mechanisms to release the localized stress induced by the coupling effect, which is validated by the TEM observations. The classical conservation law of Burgers vector cannot be applied during such decomposition process. The dislocation network is formed from the decomposed loops, which may initiate the irradiation creep much earlier than expected through the mechanism of climb-controlled glide of dislocations.
Effect of Interaction between Chromatin Loops on Cell-to-Cell Variability in Gene Expression.
Directory of Open Access Journals (Sweden)
Tuoqi Liu
2016-05-01
Full Text Available According to recent experimental evidence, the interaction between chromatin loops, which can be characterized by three factors-connection pattern, distance between regulatory elements, and communication form, play an important role in determining the level of cell-to-cell variability in gene expression. These quantitative experiments call for a corresponding modeling effect that addresses the question of how changes in these factors affect variability at the expression level in a systematic rather than case-by-case fashion. Here we make such an effort, based on a mechanic model that maps three fundamental patterns for two interacting DNA loops into a 4-state model of stochastic transcription. We first show that in contrast to side-by-side loops, nested loops enhance mRNA expression and reduce expression noise whereas alternating loops have just opposite effects. Then, we compare effects of facilitated tracking and direct looping on gene expression. We find that the former performs better than the latter in controlling mean expression and in tuning expression noise, but this control or tuning is distance-dependent, remarkable for moderate loop lengths, and there is a limit loop length such that the difference in effect between two communication forms almost disappears. Our analysis and results justify the facilitated chromatin-looping hypothesis.
Directory of Open Access Journals (Sweden)
P. K. Vijayan
2008-01-01
Full Text Available In natural circulation loops, the driving force is usually low as it depends on the riser height which is generally of the order of a few meters. The heat transport capability of natural circulation loops (NCLs is directly proportional to the flow rate it can generate. With low driving force, the straightforward way to enhance the flow is to reduce the frictional losses. A simple way to do this is to increase the loop diameter which can be easily adopted in pressure tube designs such as the AHWR and the natural circulation boilers employed in fossil-fuelled power plants. Further, the loop diameter also plays an important role on the stability behavior. An extensive experimental and theoretical investigation of the effect of loop diameter on the steady state and stability behavior of single- and two-phase natural circulation loops have been carried out and the results of this study are presented in this paper.
effects of load and speed variations in a modified closed loop v/f
African Journals Online (AJOL)
2012-11-03
Nov 3, 2012 ... Abstract. This paper investigates the effects of load and reference speed variations in a modified closed loop v/f induction motor drive. A modified approach, involving the addition of a low frequency boost voltage, is developed and adopted as an enhancement to the conventional closed loop v/f speed.
Dilaton, antisymmetric tensor and gauge fields in string effective theories at the one-loop level
International Nuclear Information System (INIS)
Mayr, P.; Stieberger, S.
1994-01-01
We investigate the dependence of the gauge couplings on the dilaton field in string effective theories at the one-loop level. First we resolve the discrepancies between statements based on symmetry considerations and explicit calculations in string effective theories on this subject. A calculation of the relevant one-loop scattering amplitudes in string theory gives us further information and allows us to derive the exact form of the corresponding effective lagrangian. In particular there is no dilaton dependent one-loop correction to the holomorphic f - function arising from massive string modes in the loop. In addition we address the coupling of the antisymmetric tensor field to the gauge bosons at one loop. While the string S-matrix elements are not reproduced using the usual supersymmetric lagrangian with the chiral superfield representation for the dilaton field, the analogue lagrangian with the dilaton in a linear multiplet naturally gives the correct answer. (orig.)
Loop corrections to string effective action: calculation scheme and α'→0 expansion
International Nuclear Information System (INIS)
Tsejtlin, A.A.
1988-01-01
A scheme of calculating loop corrections to the effective action for the massless modes of the string is discussed. Arguments are presented which show that the effective action is free of modular (and ultraviolet) divergences. Modular divergences arise only if the S matrix is calculated in the vicinity of the background which is not a solution of effective equations. The α'→0 limit of one-loop string amplitudes is considered. It is shown how the divergent part of the one-loop effective action in the (super) Yang-Mills theory is obtained from the theory of open (super) strings
Loop corrections to the string effective action: computational scheme and α'→0 expansion
International Nuclear Information System (INIS)
Tseitlin, A.A.
1988-01-01
A scheme for calculating the string loop corrections to the effective action for the massless string modes is discussed. Arguments are presented which suggest that the effective action is free of modular (and ultraviolet) divergences. Modular divergences arise only in the calculation of the S-matrix about a background which is not a solution of the effective equations. The limit α'→0 of the one-loop string amplitudes is considered, and it is demonstrated that the divergent part of the one-loop effective action in (supersymmetric) Yang--Mills theory can be obtained from the theory of open (super)strings
In vivo delamination of coronary guidewire polytetrafluoroethylene layer – A dreaded complication
Directory of Open Access Journals (Sweden)
Anshul Kumar Gupta
2016-03-01
Full Text Available Coronary guidewires are coated with polytetrafluoroethylene (PTFE layer to decrease resistance and enhance trackability. Delamination and embolization of PTFE material can be detrimental during percutaneous coronary interventions. We report an occurrence of such delamination and discuss the implications and possible mechanism of this dreaded complication.
Two-loop effective potential for Wess-Zumino model using superfields
International Nuclear Information System (INIS)
Santos, R.P. dos; Srivastava, P.P.
1985-10-01
For the case of several interacting chiral superfields the propagators for the unconstrained superfield potentials in the 'shifted' theory, where the supersymmetry is explicitly broken, are derived in a compact form. They are used to compute one-loop effective potential in the general case, while a superfield calculation of renormalized effective potential to two loops for the Wess-Zumino model is performed. (author)
One-loop effects of a heavy Higgs boson: A functional approach
International Nuclear Information System (INIS)
Dittmaier, S.; Grosse-Knetter, C.
1995-01-01
We integrate out the Higgs boson in the electroweak standard model at one loop, assuming that it is very heavy. We construct a low-energy effective Lagrangian, which parametrizes the one-loop effect of the heavy Higgs boson at OE(M O- H ). Instead of applying conventional diagrammatical techniques, we integrate out the Higgs boson directly in the path integral. copyright 1995 American Institute of Physics
Pathological demand avoidance: my thoughts on looping effects and commodification of autism
Woods, R
2017-01-01
Hacking suggests autism is a human kind, and has used autism to discuss their evolution over time. Looping effects caused the autism human kind to evolve since 1995, with people identifying with the autism human kind, and the commodification of the autism human kind by the autism industry. Pathological demand avoidance (PDA) was created from the looping effects controlled by the autism industry. This has undermined autism self-advocacy by supporting the medical paradigm of the autism human ki...
Low-energy effective action in two-dimensional SQED: a two-loop analysis
Samsonov, I. B.
2017-07-01
We study two-loop quantum corrections to the low-energy effective actions in N=(2,2) and N=(4,4) SQED on the Coulomb branch. In the latter model, the low-energy effective action is described by a generalized Kähler potential which depends on both chiral and twisted chiral superfields. We demonstrate that this generalized Kähler potential is one-loop exact and corresponds to the N=(4,4) sigma-model with torsion presented by Roček, Schoutens and Sevrin [1]. In the N=(2,2) SQED, the effective Kähler potential is not protected against higher-loop quantum corrections. The two-loop quantum corrections to this potential and the corresponding sigma-model metric are explicitly found.
Discreteness Corrections to the Effective Hamiltonian of Isotropic Loop Quantum Cosmology
Banerjee, Kinjal; Date, Ghanashyam
2005-01-01
One of the qualitatively distinct and robust implication of Loop Quantum Gravity (LQG) is the underlying discrete structure. In the cosmological context elucidated by Loop Quantum Cosmology (LQC), this is manifested by the Hamiltonian constraint equation being a (partial) difference equation. One obtains an effective Hamiltonian framework by making the continuum approximation followed by a WKB approximation. In the large volume regime, these lead to the usual classical Einstein equation which...
Improved hard-thermal-loop effective action for hot QED and QCD
International Nuclear Information System (INIS)
Flechsig, F.; Rebhan, A.K.
1995-01-01
The conventional results for hard thermal loops, which are the building blocks of resummed perturbation theory in thermal field theories, have collinear singularities when external momenta are light-like. It is shown that by taking into account asymptotic thermal masses these singularities are removed. The thus improved hard thermal loops can be summarized by compact gauge-invariant effective actions, generalizing the ones found by Taylor and Wong, and by Braaten and Pisarski. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Trinkaus, H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Festkoerperforschung; Singh, B.N. [Materials Research Department, Risoe National Laboratory, DK-4000 Roskilde (Denmark); Foreman, A.J.E. [Materials Performance Department, Harwell Laboratory, Oxfordshire OX11 0RA (United Kingdom)
1997-11-01
In metals and alloys subjected to cascade damage dislocations are frequently found to be decorated with a high density of small clusters of self-interstitial atoms (SIAs) in the form of dislocation loops. In the present paper it is shown that this effect may be attributed to the glide and trapping of SIA loops, produced directly in cascades (rather than to the enhanced agglomeration of single SIAs), in the strain field of the dislocations. The conditions for the accumulation of glissile SIA loops near dislocations as well as the dose and temperature dependencies of this phenomenon are discussed. It is suggested that the decoration of dislocations with loops may play a key role in radiation hardening subjected to cascade damage. It is shown, for example, that the increase in the upper yield stress followed by a yield drop and plastic instability in metals andalloys subjected to cascade damage cannot be rationalized in terms of conventional dispersed barrier hardening (DBH) but may be understood in terms of cascade induced source hardening (CISH) in which the dislocations are considered to be locked by the loops decorating them. Estimates for the stress necessary to pull a dislocation away from its loop `cloud` are used to discuss the dose and temperature dependence of plastic flow initiation. (orig.). 55 refs.
International Nuclear Information System (INIS)
Trinkaus, H.; Foreman, A.J.E.
1997-01-01
In metals and alloys subjected to cascade damage dislocations are frequently found to be decorated with a high density of small clusters of self-interstitial atoms (SIAs) in the form of dislocation loops. In the present paper it is shown that this effect may be attributed to the glide and trapping of SIA loops, produced directly in cascades (rather than to the enhanced agglomeration of single SIAs), in the strain field of the dislocations. The conditions for the accumulation of glissile SIA loops near dislocations as well as the dose and temperature dependencies of this phenomenon are discussed. It is suggested that the decoration of dislocations with loops may play a key role in radiation hardening subjected to cascade damage. It is shown, for example, that the increase in the upper yield stress followed by a yield drop and plastic instability in metals andalloys subjected to cascade damage cannot be rationalized in terms of conventional dispersed barrier hardening (DBH) but may be understood in terms of cascade induced source hardening (CISH) in which the dislocations are considered to be locked by the loops decorating them. Estimates for the stress necessary to pull a dislocation away from its loop 'cloud' are used to discuss the dose and temperature dependence of plastic flow initiation. (orig.)
Peeled Guidewire Coating with Debulked Plaque Obtained by Directional Coronary Atherectomy
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Rikuta Hamaya
2017-01-01
Full Text Available Percutaneous directional coronary atherectomy (DCA is a plaque debulking method performed in Japan, and recently a renewed DCA device has been launched. We present a case with a tight left anterior descending lesion undergoing percutaneous coronary intervention with application of DCA. After several sessions of DCA, white plaques accompanied by green, stringed materials were obtained from the device; some materials were considerably long (approximately 15 mm in length. A drug-eluting stent was subsequently implanted, and the procedure was completed successfully without any complications. The extracted plaques and artificial materials were pathologically examined, and no inflammatory changes were detected on plaques adjacent to the material. Assessing pathological findings and structure of the DCA catheter, the obtained artificial materials were considered as peeled guidewire, possibly resulting from the friction between the guidewire and metallic bearing in the housing of DCA catheter. Of note, this phenomenon has been recognized even in other DCA cases in which guidewires of the other kind are used. We report this phenomenon for the first time, warning of theoretically possible distal embolization of artificial materials caused by any debulking devices.
An assembly-type master-slave catheter and guidewire driving system for vascular intervention.
Cha, Hyo-Jeong; Yi, Byung-Ju; Won, Jong Yun
2017-01-01
Current vascular intervention inevitably exposes a large amount of X-ray to both an operator and a patient during the procedure. The purpose of this study is to propose a new catheter driving system which assists the operator in aspects of less X-ray exposure and convenient user interface. For this, an assembly-type 4-degree-of-freedom master-slave system was designed and tested to verify the efficiency. First, current vascular intervention procedures are analyzed to develop a new robotic procedure that enables us to use conventional vascular intervention devices such as catheter and guidewire which are commercially available in the market. Some parts of the slave robot which contact the devices were designed to be easily assembled and dissembled from the main body of the slave robot for sterilization. A master robot is compactly designed to conduct insertion and rotational motion and is able to switch from the guidewire driving mode to the catheter driving mode or vice versa. A phantom resembling the human arteries was developed, and the master-slave robotic system is tested using the phantom. The contact force of the guidewire tip according to the shape of the arteries is measured and reflected to the user through the master robot during the phantom experiment. This system can drastically reduce radiation exposure by replacing human effort by a robotic system for high radiation exposure procedures. Also, benefits of the proposed robot system are low cost by employing currently available devices and easy human interface.
Anatomy of Two-Loop Effective Action in Noncommutative Field Theories
Kiem, Young-jai; Rey, Soo-Jong; Sato, Haru-Tada
2002-01-01
We compute, at two-loop order, one-particle-irreducible Green functions and effective action in noncommutative $\\lambda[\\Phi^3]_\\star$-theory for both planar (g=0, h=3) and nonplanar (g=1, h=1) contributions. We adopt worldline formulation of the Feynman diagrammatics so that relation to string theory diagrammatics is made transparent in the Seiberg-Witten limit. We argue that the resulting two-loop effective action is expressible via open Wilson lines: one-particle-irreducible effective action is generating functional of connected diagrams for interacting open Wilson lines.
Peh, Wee Ming; Loh, Wann Jia; phua, ghee chee; Loo, Chian Min
2016-01-01
Guidewire retention is a severe but preventable complication from central venous catheter (CVC) insertion. There were three cases of guidewire retention during CVC insertion in the medical intensive care unit (MICU) in Singapore General Hospital, in the period between December 2011 and February 2012. The primary objective of this quality improvement project was to eliminate future incidences of guidewire retention during CVC insertion in the MICU and medical intermediate care area (MICA) via ...
Mixed heavy-light matching in the Universal One-Loop Effective Action
Ellis, Sebastian A. R.; Quevillon, Jérémie; You, Tevong; Zhang, Zhengkang
2016-11-01
Recently, a general result for evaluating the path integral at one loop was obtained in the form of the Universal One-Loop Effective Action. It may be used to derive effective field theory operators of dimensions up to six, by evaluating the traces of matrices in this expression, with the mass dependence encapsulated in the universal coefficients. Here we show that it can account for loops of mixed heavy-light particles in the matching procedure. Our prescription for computing these mixed contributions to the Wilson coefficients is conceptually simple. Moreover it has the advantage of maintaining the universal structure of the effective action, which we illustrate using the example of integrating out a heavy electroweak triplet scalar coupling to a light Higgs doublet. Finally we also identify new structures that were previously neglected in the universal results.
Mixed heavy–light matching in the Universal One-Loop Effective Action
International Nuclear Information System (INIS)
Ellis, Sebastian A.R.; Quevillon, Jérémie; You, Tevong; Zhang, Zhengkang
2016-01-01
Recently, a general result for evaluating the path integral at one loop was obtained in the form of the Universal One-Loop Effective Action. It may be used to derive effective field theory operators of dimensions up to six, by evaluating the traces of matrices in this expression, with the mass dependence encapsulated in the universal coefficients. Here we show that it can account for loops of mixed heavy–light particles in the matching procedure. Our prescription for computing these mixed contributions to the Wilson coefficients is conceptually simple. Moreover it has the advantage of maintaining the universal structure of the effective action, which we illustrate using the example of integrating out a heavy electroweak triplet scalar coupling to a light Higgs doublet. Finally we also identify new structures that were previously neglected in the universal results.
A gauge/gravity relation in the one-loop effective action
International Nuclear Information System (INIS)
Basar, Goekce; Dunne, Gerald V
2010-01-01
We identify an unusual new gauge/gravity relation: the one-loop effective action for a massive spinor in 2n-dimensional AdS space is expressed in terms of precisely the same function (a certain multiple gamma function) as the one-loop effective action for a massive charged scalar in 4n dimensions in a maximally symmetric background electromagnetic field (one for which the eigenvalues of F μν are maximally degenerate, corresponding in four dimensions to a self-dual field, equivalently to a field of definite helicity), subject to the identification F 2 ↔Λ, where Λ is the gravitational curvature. Since these effective actions generate the low energy limit of all one-loop multi-leg graviton or gauge amplitudes, this implies a nontrivial gauge/gravity relation at the non-perturbative level and at the amplitude level. (fast track communication)
Mixed heavy–light matching in the Universal One-Loop Effective Action
Energy Technology Data Exchange (ETDEWEB)
Ellis, Sebastian A.R. [Michigan Center for Theoretical Physics (MCTP), Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Quevillon, Jérémie [Theoretical Particle Physics and Cosmology Group, Physics Department, King' s College London, London WC2R 2LS (United Kingdom); You, Tevong [DAMTP, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Zhang, Zhengkang, E-mail: zzkevin@umich.edu [Michigan Center for Theoretical Physics (MCTP), Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States)
2016-11-10
Recently, a general result for evaluating the path integral at one loop was obtained in the form of the Universal One-Loop Effective Action. It may be used to derive effective field theory operators of dimensions up to six, by evaluating the traces of matrices in this expression, with the mass dependence encapsulated in the universal coefficients. Here we show that it can account for loops of mixed heavy–light particles in the matching procedure. Our prescription for computing these mixed contributions to the Wilson coefficients is conceptually simple. Moreover it has the advantage of maintaining the universal structure of the effective action, which we illustrate using the example of integrating out a heavy electroweak triplet scalar coupling to a light Higgs doublet. Finally we also identify new structures that were previously neglected in the universal results.
Superfield formalism for the one loop effective action and CP(N) model in three dimensions
International Nuclear Information System (INIS)
Cho, Jin-Ho; Hahn, Sang-Ok; Oh, Phillial; Park, Cheonsoo; Park, Jeong-Hyuck
2004-01-01
To obtain the one loop effective action for a given superfield theory, one encounters the notion such as the 'super trace' of a differential operator on superspace. We develop, in a systematic way for the superspace of arbitrary dimension, a method to determine the super trace precisely. We present a formula to express the super trace explicitly as the superspace integral, which enables us to write the one loop effective action within the superfield formalism and still maintain the manifest supersymmetry. In the second part of the paper, we apply the result to a three dimensional N=1 supersymmetric CP(N) model in the auxiliary superfield formalism. The model contains a novel topological interaction term. We show in the large N limit the one loop effective action is given by the supersymmetric Maxwell-Chern-Simons theory. (author)
Unexpected extra-renal effects of loop diuretics in the preterm neonate.
Cotton, Robert; Suarez, Sandra; Reese, Jeff
2012-08-01
The loop diuretics furosemide and bumetanide are commonly used in neonatal intensive care units (NICUs). Furosemide, because of its actions on the ubiquitous Na(+) -K(+) -2Cl(-) isoform cotransporter and its promotion of prostanoid production and release, also has non-diuretic effects on vascular smooth muscle, airways, the ductus arteriosus and theoretically the gastrointestinal tract. Loop diuretics also affect the central nervous system through modulation of the GABA-A chloride channel. The loop diuretics have a variety of biological effects that are potentially harmful as well as beneficial. Care should be taken with the use of these agents because the range of their effects may be broader than the single action sought by the prescribing physician. © 2012 The Author(s)/Acta Paediatrica © 2012 Foundation Acta Paediatrica.
Effects of the amorphization on hysteresis loops of the amorphous spin-1/2 Ising system
International Nuclear Information System (INIS)
Essaoudi, I.; Ainane, A.; Saber, M.; Miguel, J.J. de
2009-01-01
We examine the effects of the amorphization on the hysteresis loops of the amorphous spin-1/2 Ising system using the effective field theory within a probability distribution technique that accounts for the self-spin correlation functions. The magnetization, the transverse and longitudinal susceptibilities, and pyromagnetic coefficient are also studied in detail
Loop expansion of the average effective action in the functional renormalization group approach
Lavrov, Peter M.; Merzlikin, Boris S.
2015-10-01
We formulate a perturbation expansion for the effective action in a new approach to the functional renormalization group method based on the concept of composite fields for regulator functions being their most essential ingredients. We demonstrate explicitly the principal difference between the properties of effective actions in these two approaches existing already on the one-loop level in a simple gauge model.
Leptonic contributions to the effective electromagnetic coupling at four-loop order in QED
International Nuclear Information System (INIS)
Sturm, Christian
2013-01-01
The running of the effective electromagnetic coupling is for many electroweak observables the dominant correction. It plays an important role for deriving constraints on the Standard Model in the context of electroweak precision measurements. We compute the four-loop QED corrections to the running of the effective electromagnetic coupling and perform a numerical evaluation of the different gauge invariant subsets
One-loop effects in a self-dual planar noncommutative theory
International Nuclear Information System (INIS)
Fosco, C.D.; Moreno, G.A.
2007-01-01
We study the UV properties, and derive the explicit form of the one-loop effective action, for a noncommutative complex scalar field theory in 2+1 dimensions with a Grosse-Wulkenhaar term, at the self-dual point. We also consider quantum effects around non-trivial minima of the classical action which appear when the potential allows for the spontaneous breaking of the U(1) symmetry. For those solutions, we show that the one-loop correction to the vacuum energy is a function of a special combination of the amplitude of the classical solution and the coupling constant
Extending the Universal One-Loop Effective Action: heavy-light coefficients
Ellis, Sebastian A. R.; Quevillon, Jérémie; You, Tevong; Zhang, Zhengkang
2017-08-01
The Universal One-Loop Effective Action (UOLEA) is a general expression for the effective action obtained by evaluating in a model-independent way the one-loop expansion of a functional path integral. It can be used to match UV theories to their low-energy EFTs more efficiently by avoiding redundant steps in the application of functional methods, simplifying the process of obtaining Wilson coefficients of operators up to dimension six. In addition to loops involving only heavy fields, matching may require the inclusion of loops containing both heavy and light particles. Here we use the recently-developed covariant diagram technique to extend the UOLEA to include heavy-light terms which retain the same universal structure as the previously-derived heavy-only terms. As an example of its application, we integrate out a heavy singlet scalar with a linear coupling to a light doublet Higgs. The extension presented here is a first step towards completing the UOLEA to incorporate all possible structures encountered in a covariant derivative expansion of the one-loop path integral.
Effectiveness of flossing loops in the control of the gingival health.
Azcarate-Velázquez, Francisco; Garrido-Serrano, Roberto; Castillo-Dalí, Gabriel; Serrera-Figallo, María-Angeles; Gañán-Calvo, Alfonso; Torres-Lagares, Daniel
2017-06-01
One of the key factor in the good condition of periodontal tissues is their daily hygiene. Oral hygiene techniques such brushing and a good interdental hygiene by correct flossing are very important. The aim of this study is to compare the use of dental floss in a loop vs traditional floss in the control of Loe-Silness Gingival Index (IG), Turesky´s Plaque Index (IPT), Gingival Bleeding Index (IS) and the values of interleukin 6 (IL-6) and interleukin 8 (IL-8). A comparative study of 40 patients in which each patient was his own control, using during 45 days each one of the devices (new loop floss and conventional floss) of interdental hygiene analysed. Data for Loe-Silness Gingival Index (IG), Turesky´s Plaque Index (IPT), Gingival Bleeding Index (IS) and the values of interleukin 6 (IL-6) and interleukin 8 (IL-8)were collected and measured in every visit for every type of interdental hygiene device. Our data indicates that the rate of Turesky´s Plaque Index presented statistically significant differences between groups (loop: 1.66 ± 0.8; traditional: 1.12 ± 0.8; p dental floss designs try to make their use easier and more sensitive, and plaque removal more effective. The loop design can facilitate interdental hygiene, reaching similar effectiveness than traditional floss, improving some indicators, such as Turesky´s Plaque Index. Key words: Dental floss, bacterial plaque, loop floss, plaque index, periodontal diseases.
Dynamic Effects of Topoisomerase I Inhibition on R-Loops and Short Transcripts at Active Promoters.
Directory of Open Access Journals (Sweden)
Jessica Marinello
Full Text Available Topoisomerase I-DNA-cleavage complexes (Top1cc stabilized by camptothecin (CPT have specific effects at transcriptional levels. We recently reported that Top1cc increase antisense transcript (aRNAs levels at divergent CpG-island promoters and, transiently, DNA/RNA hybrids (R-loop in nuclear and mitochondrial genomes of colon cancer HCT116 cells. However, the relationship between R-loops and aRNAs was not established. Here, we show that aRNAs can form R-loops in N-TERA-2 cells under physiological conditions, and that promoter-associated R-loops are somewhat increased and extended in length immediately upon cell exposure to CPT. In contrast, persistent Top1ccs reduce the majority of R-loops suggesting that CPT-accumulated aRNAs are not commonly involved in R-loops. The enhancement of aRNAs by Top1ccs is present both in human colon cancer HCT116 cells and WI38 fibroblasts suggesting a common response of cancer and normal cells. Although Top1ccs lead to DSB and DDR kinases activation, we do not detect a dependence of aRNA accumulation on ATM or DNA-PK activation. However, we showed that the cell response to persistent Top1ccs can involve an impairment of aRNA turnover rather than a higher synthesis rate. Finally, a genome-wide analysis shows that persistent Top1ccs also determine an accumulation of sense transcripts at 5'-end gene regions suggesting an increased occurrence of truncated transcripts. Taken together, the results indicate that Top1 may regulate transcription initiation by modulating RNA polymerase-generated negative supercoils, which can in turn favor R-loop formation at promoters, and that transcript accumulation at TSS is a response to persistent transcriptional stress by Top1 poisoning.
One-loop effective action and Schwinger effect in (anti-) de Sitter space
Cai, Rong-Gen; Kim, Sang Pyo
2014-09-01
We study the Schwinger mechanism by a uniform electric field in dS2 and AdS2 and the curvature effect on the Schwinger effect, and further propose a thermal interpretation of the Schwinger formula in terms of the Gibbons-Hawking temperature and the Unruh temperature for an accelerating charge in dS2 and an analogous expression in AdS2. The exact one-loop effective action is found in the proper-time integral in each space, which is determined by the effective mass, the Maxwell scalar, and the scalar curvature, and whose pole structure gives the imaginary part of the effective action and the exact pair-production rate. The exact pair-production rate is also given the thermal interpretation.
Close-loop simulation of the medial olivocochlear anti-masking effects
Liu, Yi-Wen; Yu, Lu-Ming; Wu, Po-Jui
2015-12-01
The medial olivocochlear reflex (MOCR) is known to affect cochlear signal processing via the electromechanical changes it induces in outer hair cells (OHCs). Experiments showed that electrically stimulating the MOC efferents (i.e., open-loop stimulation) suppresses cochlear responses to acoustic noise while enhancing the response to tone bursts if the signal-to-noise ratio is sufficiently high [5]. However, such experiments did not reveal precisely how MOCR affects cochlear signal processing in a close loop. Presently we have built an integrated computer model for the MOCR pathway; the constituting sub-models include a model for cochlear mechanics with electromotile OHCs [11], a neurotransmitter release model for the synapse between inner hair cells (IHCs) and spiral ganglion cells [16], an electrical model for the T-multipolar (TM) cells in the cochlear nucleus [6], a relay from TM cells to the MOC interneurons, and a convolution kernel describing the change of OHC potassium conductance triggered by the MOC inhibitory post synaptic potentials. Thus, close-loop responses of the entire system can be simulated for arbitrary acoustic stimuli. Both open-loop and close-loop simulations demonstrate a decrease in the auditory nerve fiber (ANF) response to noise but an increase in the response to high-level tone bursts. The present integrated computer model can potentially be used for testing hypotheses regarding the physiological mechanisms for MOC anti-masking effects.
The impact of two-loop effects on the scenario of MSSM Higgs alignment without decoupling
Energy Technology Data Exchange (ETDEWEB)
Haber, Howard E.; Stefaniak, Tim [University of California, Santa Cruz Institute for Particle Physics (SCIPP) and Department of Physics, Santa Cruz, CA (United States); Heinemeyer, Sven [Campus of International Excellence UAM+CSIC, Madrid (Spain); Universidad Autonoma de Madrid, Instituto de Fisica Teorica, (UAM/CSIC), Madrid (Spain); Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain)
2017-11-15
In multi-Higgs models, the properties of one neutral scalar state approximate those of the Standard Model (SM) Higgs boson in a limit where the corresponding scalar field is roughly aligned in field space with the scalar doublet vacuum expectation value. In a scenario of alignment without decoupling, a SM-like Higgs boson can be accompanied by additional scalar states whose masses are of a similar order of magnitude. In the Minimal Supersymmetric Standard Model (MSSM), alignment without decoupling can be achieved due to an accidental cancellation of tree-level and radiative loop-level effects. In this paper we assess the impact of the leading two-loop O(α{sub s}h{sub t}{sup 2}) corrections on the Higgs alignment condition in the MSSM. These corrections are sizable and important in the relevant regions of parameter space and furthermore give rise to solutions of the alignment condition that are not present in the approximate one-loop description. We provide a comprehensive numerical comparison of the alignment condition obtained in the approximate one-loop and two-loop approximations, and discuss its implications for phenomenologically viable regions of the MSSM parameter space. (orig.)
Dispersion relations from the hard thermal loop effective action in a magnetic field
Elmfors, Per
1995-01-01
Dispersion relations for fermions at high temperature and in a background magnetic field are calculated in two different ways. First from a straightforward one-loop calculation where, in the weak field limit, we find an expression closely related to the standard dispersion relations in the absence of the magnetic field. Secondly, we derive the dispersion relations directly from the Hard Thermal Loop effective action, which allows for an exact solution (i.e. to all orders in the external field), up to the last numerical integrals.
String-loop corrections to effective action and black-hole instabilities
International Nuclear Information System (INIS)
Belokurov, V.V.; Iofa, M.Z.
1994-07-01
Following the ideas of Ellis, Mavromatos and Nanopoulos, to account for instability of 2D black-hole solution, we discuss possible imaginary string-loop corrections to the coefficient at the Einstein term in string effective action. In closed bosonic string theory, such corrections appear because of the tachyon contribution to the integration measure over the moduli. In superstring theory (in critical as well as in non-critical dimensions), no one-string-loop complex corrections to the Einstein term are generated and the mechanism for generating black-hole instabilities proposed above fails. (author). 21 refs
Two loop effective Kahler potential of (non)-renormalizable supersymmetric models
International Nuclear Information System (INIS)
Groot Nibbelink, S.; Nyawelo, T.S.
2005-10-01
We perform a supergraph computation of the effective Kahler potential at one and two loops for general four dimensional N=1 supersymmetric theories described by arbitrary Kahler potential, superpotential and gauge kinetic function. We only insist on gauge invariance of the Kahler potential and the superpotential as we heavily rely on its consequences in the quantum theory. However, we do not require gauge invariance for the gauge kinetic functions, so that our results can also be applied to anomalous theories that involve the Green-Schwarz mechanism. We illustrate our two loop results by considering a few simple models: the (non-)renormalizable Wess-Zumino model and Super Quantum Electrodynamics. (author)
String states, loops and effective actions in noncommutative field theory and matrix models
Energy Technology Data Exchange (ETDEWEB)
Steinacker, Harold C., E-mail: harold.steinacker@univie.ac.at
2016-09-15
Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
String states, loops and effective actions in noncommutative field theory and matrix models
Directory of Open Access Journals (Sweden)
Harold C. Steinacker
2016-09-01
Full Text Available Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
On the heterotic effective action at one-loop, gauge couplings and the gravitational sector
Kiritsis, E.; Petropoulos, P.M.; Rizos, J.
1996-01-01
We present in detail the procedure for calculating the heterotic one-loop effective action. We focus on gravitational and gauge couplings. We show that the two-derivative couplings of the gravitational sector are not renormalized at one loop when the ground state is supersymmetric. Arguments are presented that this non-renormalization theorem persists to all orders in perturbation theory. Arguments are presented that this non-renormalization theorem persists to all orders in perturbation theory. We also derive the full one-loop correction to the gauge coupling. For a class of N=2 ground states, namely those that are obtained by toroidal compactification to four dimensions of generic six-dimensional N=1 models, we give an explicit formula for the gauge-group independent thresholds, and show that these are equal within the whole family.
A Cost-Effective Approach to Hardware-in-the-Loop Simulation
DEFF Research Database (Denmark)
Pedersen, Mikkel Melters; Hansen, M. R.; Ballebye, M.
2012-01-01
This paper presents an approach for developing cost effective hardware-in-the- loop (HIL) simulation platforms for the use in controller software test and development. The approach is aimed at the many smaller manufacturers of e.g. mobile hydraulic machinery, which often do not have very advanced...
Higgs Decay to Two Photons at One Loop in the Standard Model Effective Field Theory.
Hartmann, Christine; Trott, Michael
2015-11-06
We present the calculation of the CP conserving contributions to Γ(h→γγ), from dimension six operators at one-loop order, in the linear standard model effective field theory. We discuss the impact of these corrections on interpreting current and future experimental bounds on this decay.
Effect of closed loop cooling water transit time on containment cooling
International Nuclear Information System (INIS)
Smith, R.P.; Vossahlik, J.E.; Goodwin, E.F.
1996-01-01
Long term containment cooling analyses in nuclear plant systems are usually conducted assuming a quasi steady-state process, that is, a steady state evaluation of the cooling system is completed for each calculational step. In reality, fluid transport in the system, and heat addition to system components may affect the heat removal rate of the system. Transient effects occurring during system startup may affect the maximum temperatures experienced in the system. It is important to ensure that such transient effects do not affect operation of the system (e.g., cause a high temperature trip). To evaluate the effect of fluid transit delays, a closed loop cooling water system model has been developed that incorporates the fluid transport times when determining the closed loop cooling system performance. This paper describes the closed loop cooling system model as implemented in the CONTEMPT-LT/028 code. The evaluation of the transient temperature response of the closed loop cooling system using the model is described. The paper also describes the effect of fluid transit time on the overall containment cooling performance
Energy Technology Data Exchange (ETDEWEB)
Warne, Larry Kevin; Lucero, Larry Martin; Langston, William L.; Salazar, Robert Austin; Coleman, Phillip Dale; Basilio, Lorena I.; Bacon, Larry Donald
2012-05-01
This report estimates inductively-coupled energy to a low-impedance load in a loop-to-loop arrangement. Both analytical models and full-wave numerical simulations are used and the resulting fields, coupled powers and energies are compared. The energies are simply estimated from the coupled powers through approximations to the energy theorem. The transmitter loop is taken to be either a circular geometry or a rectangular-loop (stripline-type) geometry that was used in an experimental setup. Simple magnetic field models are constructed and used to estimate the mutual inductance to the receiving loop, which is taken to be circular with one or several turns. Circuit elements are estimated and used to determine the coupled current and power (an equivalent antenna picture is also given). These results are compared to an electromagnetic simulation of the transmitter geometry. Simple approximate relations are also given to estimate coupled energy from the power. The effect of additional loads in the form of attached leads, forming transmission lines, are considered. The results are summarized in a set of susceptibility-type curves. Finally, we also consider drives to the cables themselves and the resulting common-to-differential mode currents in the load.
Effect of DNA hairpin loops on the twist of planar DNA origami tiles.
Li, Zhe; Wang, Lei; Yan, Hao; Liu, Yan
2012-01-31
The development of scaffolded DNA origami, a technique in which a long single-stranded viral genome is folded into arbitrary shapes by hundreds of short synthetic oligonucleotides, represents an important milestone in DNA nanotechnology. Recent findings have revealed that two-dimensional (2D) DNA origami structures based on the original design parameters adopt a global twist with respect to the tile plane, which may be because the conformation of the constituent DNA (10.67 bp/turn) deviates from the natural B-type helical twist (10.4 bp/turn). Here we aim to characterize the effects of DNA hairpin loops on the overall curvature of the tile and explore their ability to control, and ultimately eliminate any unwanted curvature. A series of dumbbell-shaped DNA loops were selectively displayed on the surface of DNA origami tiles with the expectation that repulsive interactions among the neighboring dumbbell loops and between the loops and the DNA origami tile would influence the structural features of the underlying tiles. A systematic, atomic force microscopy (AFM) study of how the number and position of the DNA loops influenced the global twist of the structure was performed, and several structural models to explain the results were proposed. The observations unambiguously revealed that the first generation of rectangular shaped origami tiles adopt a conformation in which the upper right (corner 2) and bottom left (corner 4) corners bend upward out of the plane, causing linear superstructures attached by these corners to form twisted ribbons. Our experimental observations are consistent with the twist model predicted by the DNA mechanical property simulation software CanDo. Through the systematic design and organization of various numbers of dumbbell loops on both surfaces of the tile, a nearly planar rectangular origami tile was achieved. © 2011 American Chemical Society
The one-loop effective action of noncommutative {\\cal N}=4 super Yang-Mills is gauge invariant
Pernici, Mario; Santambrogio, Alberto; Zanon, Daniela
2000-01-01
We study the gauge transformation of the recently computed one-loop four-point function of {\\cal N}=4 supersymmetric Yang-Mills theory with gauge group U(N). The contributions from nonplanar diagrams are not gauge invariant. We compute their gauge variation and show that it is cancelled by the variation from corresponding terms of the one-loop five-point function. This mechanism is general: it insures the gauge invariance of the noncommutative one-loop effective action.
Renormalization of the one-loop effective action on an arbitrary curved space-time: A general method
International Nuclear Information System (INIS)
Cognola, G.
1994-01-01
Using ζ-function regularization for the one-loop effective action, we carry out the renormalization of the one-loop effective Lagrangian for a self-interacting scalar field theory in an arbitrary gravitational background. We give very general expressions and recover known results as special cases
One-loop effective actions and higher spins. Part II
Bonora, L.; Cvitan, M.; Prester, P. Dominis; Giaccari, S.; Štemberga, T.
2018-01-01
In this paper we continue and improve the analysis of the effective actions obtained by integrating out a scalar and a fermion field coupled to external symmetric sources, started in the previous paper. The first subject we study is the geometrization of the results obtained there, that is we express them in terms of covariant Jacobi tensors. The second subject concerns the treatment of tadpoles and seagull terms in order to implement off-shell covariance in the initial model. The last and by far largest part of the paper is a repository of results concerning all two point correlators (including mixed ones) of symmetric currents of any spin up to 5 and in any dimensions between 3 and 6. In the massless case we also provide formulas for any spin in any dimension.
An addendum to the Heisenberg-Euler effective action beyond one loop
International Nuclear Information System (INIS)
Gies, Holger; Karbstein, Felix
2017-01-01
We study the effective interactions of external electromagnetic fields induced by fluctuations of virtual particles in the vacuum of quantum electrodynamics. Our main focus is on these interactions at two-loop order. We discuss in detail the emergence of the renowned Heisenberg-Euler effective action from the underlying microscopic theory of quantum electrodynamics, emphasizing its distinction from a standard one-particle irreducible effective action. In our explicit calculations we limit ourselves to constant and slowly varying external fields, allowing us to adopt a locally constant field approximation. One of our main findings is that at two-loop order there is a finite one-particle reducible contribution to the Heisenberg-Euler effective action in constant fields, which was previously assumed to vanish. In addition to their conceptual significance, our results are relevant for high-precision probes of quantum vacuum nonlinearity in strong electromagnetic fields.
An addendum to the Heisenberg-Euler effective action beyond one loop
Energy Technology Data Exchange (ETDEWEB)
Gies, Holger; Karbstein, Felix [Helmholtz-Institut Jena,Fröbelstieg 3, 07743 Jena (Germany); Theoretisch-Physikalisches Institut, Abbe Center of Photonics,Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany)
2017-03-21
We study the effective interactions of external electromagnetic fields induced by fluctuations of virtual particles in the vacuum of quantum electrodynamics. Our main focus is on these interactions at two-loop order. We discuss in detail the emergence of the renowned Heisenberg-Euler effective action from the underlying microscopic theory of quantum electrodynamics, emphasizing its distinction from a standard one-particle irreducible effective action. In our explicit calculations we limit ourselves to constant and slowly varying external fields, allowing us to adopt a locally constant field approximation. One of our main findings is that at two-loop order there is a finite one-particle reducible contribution to the Heisenberg-Euler effective action in constant fields, which was previously assumed to vanish. In addition to their conceptual significance, our results are relevant for high-precision probes of quantum vacuum nonlinearity in strong electromagnetic fields.
EFFECTS OF A BAND LOOP ON LOWER EXTREMITY MUSCLE ACTIVITY AND KINEMATICS DURING THE BARBELL SQUAT.
Foley, Ryan C A; Bulbrook, Brittany D; Button, Duane C; Holmes, Michael W R
2017-08-01
Medial knee collapse can signal an underlying movement issue that, if uncorrected, can lead to a variety of knee injuries. Placing a band around the distal thigh may act as a proprioceptive aid to minimize medial collapse of the knee during squats; however, little is known about EMG and biomechanics in trained and untrained individuals during the squat with an elastic band added. To investigate the effects of the TheraBand® Band Loop on kinematics and muscle activity of the lower extremity during a standard barbell back squat at different intensities in both trained and untrained individuals. Cross-sectional, repeated measures. Sixteen healthy, male, university aged-participants were split into two groups of eight, consisting of a trained and untrained group. Participants performed both a 3-repetition maximum (3-RM) and a bodyweight load squat for repetitions to failure. Lower extremity kinematics and surface electromyography of four muscles were measured bilaterally over two sessions, an unaided squat and a band session (band loop placed around distal thighs). Medial knee collapse, measured as a knee width index, and maximum muscle activity were calculated. During the 3-RM, squat weight was unaffected by band loop intervention (p = 0.486) and the trained group lifted more weight than the untrained group (pbarbell squat strength by increasing activation of agonist muscles more than traditional, un-banded squats. Greater maximal muscle activity in most muscles during band loop sessions may provide enhanced knee stability via increased activation of stabilizing muscles. 3.
Nabeshima, Tatsuhide; Kanno, Atsushi; Masamune, Atsushi; Hayashi, Hiroki; Hongo, Seiji; Yoshida, Naoki; Nakano, Eriko; Miura, Shin; Hamada, Shin; Kikuta, Kazuhiro; Kume, Kiyoshi; Hirota, Morihisa; Unno, Michiaki; Shimosegawa, Tooru
2017-01-01
Pancreaticojejunostomy stricture (PJS) is a late complication of pancreaticoduodenectomy. The endoscopic treatment of PJS is very challenging due to the difficulty of locating the small anastomotic site and passing the stricture using a guidewire. We herein report two cases of severe PJS. These patients could not be treated using only double-balloon endoscopy or endoscopic ultrasound-guided puncture of the main pancreatic duct because of severe stenosis at the anastomotic site. However, we could treat them by the rendezvous technique using the rigid part of the guidewire to penetrate PJS. This method was useful and safe for treating severe PJS. PMID:29151507
Type II and heterotic one loop string effective actions in four dimensions
International Nuclear Information System (INIS)
Moura, Filipe
2007-01-01
We analyze the reduction to four dimensions of the R 4 terms which are part of the ten-dimensional string effective actions, both at tree level and one loop. We show that there are two independent combinations of R 4 present, at one loop, in the type IIA four dimensional effective action, which means they both have their origin in M-theory. The d = 4 heterotic effective action also has such terms. This contradicts the common belief that there is only one R 4 term in four-dimensional supergravity theories, given by the square of the Bel-Robinson tensor. In pure N = 1 supergravity this new R 4 combination cannot be directly supersymmetrized, but we show that, when coupled to a scalar chiral multiplet (violating the U(1) R-symmetry), it emerges in the action after elimination of the auxiliary fields
Dominant two-loop corrections to the MSSM finite temperature effective potential
International Nuclear Information System (INIS)
Espinosa, J.R.
1996-04-01
We show that two-loop corrections to the finite temperature effective potential in the MSSM can have a dramatic effect on the strength of the electroweak phase transition, making it more strongly first order. The change in the order parameter v/Tc can be as large as 75% of the one-loop daisy improved result. This effect can be decisive to widen the region in parameter space where erasure of the created baryons by sphaleron processes after the transition is suppressed and hence, where electroweak baryogenesis might be successful. We find an allowed region with tan β< or∼4.5 and a Higgs boson with standard couplings and mass below 80 GeV within the reach of LEP II. (orig.)
Fractured Guidewire during Left Ventricular Lead Insertion: A First Case Report
Directory of Open Access Journals (Sweden)
Shuzo Nishihara, MD
2010-01-01
Full Text Available We report on a 77-year-old man who had been diagnosed with diabetes and hypertension. He had also been diagnosed with cardiomyopathy, although details were unclear. He was referred from local clinics after becoming aware of shortness of breath on exertion. Electrocardiogram showed a 2:1 atrioventriculer block with a wide QRS beat. Echocardiography and cardiac MRI showed very poor left ventricular contraction with chamber dilatation. Echocardiography showed left bundle branch block with dyssynchrony. On the electrophysiological testing, ventricular tachycardia and ventricular fibrillation were not induced, and no significant findings on coronary angiography had revealed at that time. He had shortness of breath on exertion with bradycardia-tachycardia syndrome and low cardiac function, and his electrophysiological examination was negative. Therefore we decided to implamt cardiac resynchronization therapy pacemaker (CRT-P. During a guide-wire insertion for placement of the left ventricular lead into the coronary venous branch, the tip of the guide-wire suddenly broke off. We attempted to recover the fragment using a snare catheter, but were unsuccessful. Since then the patient has been under observation, with no clinical manifestations seen.
One-loop effects from spin-1 resonances in Composite Higgs models
Contino, Roberto
2015-01-01
We compute the 1-loop correction to the electroweak observables from spin-1 resonances in SO(5)/SO(4) composite Higgs models. The strong dynamics is modeled with an effective description comprising the Nambu-Goldstone bosons and the lowest-lying spin-1 resonances. A classification is performed of the relevant operators including custodially-breaking effects from the gauging of hypercharge. The 1-loop contribution of the resonances is extracted in a diagrammatic approach by matching to the low-energy theory of Nambu-Goldstone bosons. We find that the correction is numerically important in a significant fraction of the parameter space and tends to weaken the bounds providing a negative shift to the S parameter.
New Constraints on Dark Matter Effective Theories from Standard Model Loops
Crivellin, Andreas; Procura, Massimiliano
2014-01-01
We consider an effective field theory for a gauge singlet Dirac dark matter (DM) particle interacting with the Standard Model (SM) fields via effective operators suppressed by the scale $\\Lambda \\gtrsim 1$ TeV. We perform a systematic analysis of the leading loop contributions to spin-independent (SI) DM--nucleon scattering using renormalization group evolution between $\\Lambda$ and the low-energy scale probed by direct detection experiments. We find that electroweak interactions induce operator mixings such that operators that are naively velocity-suppressed and spin-dependent can actually contribute to SI scattering. This allows us to put novel constraints on Wilson coefficients that were so far poorly bounded by direct detection. Constraints from current searches are comparable to LHC bounds, and will significantly improve in the near future. Interestingly, the loop contribution we find is maximally isospin violating even if the underlying theory is isospin conserving.
Effects of intact loop hydraulic resistance of PWR LOCA behavior in scaled experimental facilities
Energy Technology Data Exchange (ETDEWEB)
Jacoby, M.S.
1977-09-01
The scaling of experiments in the Water Reactor Safety Program has been on a power/volume basis. This scaling philosophy has resulted in good thermal modeling of the core, but, combined with core design considerations, compromises the modeling of the hydraulic resistance in the intact loop. Tests in LOFT, Semiscale MOD-1 and FLECHT-SET have been conducted for the purpose of determining the effect of scaling hydraulic resistance to core area ratio (low hydraulic resistance) or to core power ratio (high hydraulic resistance). The results of these tests, together with computer model results using RELAP4/MOD5, RE-FRAP, and FLOOD4, were studied to determine the effects of the scaling compromise. The review of available information has shown no significant results of varying intact loop hydraulic resistance.
Examples of the Vilkovisky-Dewitt effective action in one-loop quantum gravity
Allen, Bruce; Mc Laughlin, John G.; Ottewill, Adrian C.
1992-01-01
We present two examples where the contribution of one-loop gravitons to the renormalized stress-energy tensor may be calculated explicitly from both the standard and the Vilkovisky-DeWitt effective action. The renormalization is carried out using the Hadamard renormalization procedure outlined by Allen, Folacci, and Ottewill [Phys. Rev. D 38, 1069 (1988)]. The examples show that the standard and Vilkovisky-DeWitt formulations of quantum field theory lead to different physical predictions at o...
Effects of Field-Aligned Flows on Standing Kink and Sausage Modes Supported by Coronal Loops
Chen, S.-X.; Li, B.; Xia, L.-D.; Chen, Y.-J.; Yu, H.
2014-05-01
Fundamental standing modes and their overtones play an important role in coronal seismology. We examine the effects of a significant field-aligned flow on standing modes that are supported by coronal loops, which are modeled here as cold magnetic slabs. Of particular interest are the period ratios of the fundamental to its ( n-1)th overtone [ P 1/ nP n ] for kink and sausage modes, and the threshold half-width-to-length ratio for sausage modes. For standing kink modes, the flow significantly reduces P 1/ nP n in general, the effect being particularly strong for higher n and weaker density contrast [] between loops and their surroundings. That said, even when approaches infinity, this effect is still substantial, reducing the minimal P 1/ nP n by up to 13.7 % (24.5 %) for n=2 ( n=4) relative to the static case, when the Alfvén Mach number [ M A] reaches 0.8, where M A measures the loop flow speed in units of the internal Alfvén speed. Although it is not negligible for standing sausage modes, the flow effect in reducing P 1/ nP n is not as strong. However, the threshold half-width-to-length ratio is considerably higher in the flowing case than in its static counterpart. For in the range [9,1024] and M A in the range [0,0.5], an exhaustive parameter study yields that this threshold is well fitted by , which involves the two parameters in a simple way. This allows one to analytically constrain the combination for a loop with a known width-to-length ratio when a standing sausage oscillation is identified. It also allows one to examine the idea of partial sausage modes in more detail, and the flow is found to significantly reduce the spatial extent where partial modes are allowed.
Partially massless higher-spin theory II: one-loop effective actions
Energy Technology Data Exchange (ETDEWEB)
Brust, Christopher [Perimeter Institute for Theoretical Physics,31 Caroline St. N, Waterloo, Ontario, N2L 2Y5 (Canada); Hinterbichler, Kurt [CERCA, Department of Physics, Case Western Reserve University,10900 Euclid Ave, Cleveland, OH, 44106 (United States)
2017-01-30
We continue our study of a generalization of the D-dimensional linearized Vasiliev higher-spin equations to include a tower of partially massless (PM) fields. We compute one-loop effective actions by evaluating zeta functions for both the “minimal” and “non-minimal” parity-even versions of the theory. Specifically, we compute the log-divergent part of the effective action in odd-dimensional Euclidean AdS spaces for D=7 through 19 (dual to the a-type conformal anomaly of the dual boundary theory), and the finite part of the effective action in even-dimensional Euclidean AdS spaces for D=4 through 8 (dual to the free energy on a sphere of the dual boundary theory). We pay special attention to the case D=4, where module mixings occur in the dual field theory and subtlety arises in the one-loop computation. The results provide evidence that the theory is UV complete and one-loop exact, and we conjecture and provide evidence for a map between the inverse Newton’s constant of the partially massless higher-spin theory and the number of colors in the dual CFT.
Partially massless higher-spin theory II: one-loop effective actions
Brust, Christopher; Hinterbichler, Kurt
2017-01-01
We continue our study of a generalization of the D-dimensional linearized Vasiliev higher-spin equations to include a tower of partially massless (PM) fields. We compute one-loop effective actions by evaluating zeta functions for both the "minimal" and "non-minimal" parity-even versions of the theory. Specifically, we compute the log-divergent part of the effective action in odd-dimensional Euclidean AdS spaces for D = 7 through 19 (dual to the a-type conformal anomaly of the dual boundary theory), and the finite part of the effective action in even-dimensional Euclidean AdS spaces for D = 4 through 8 (dual to the free energy on a sphere of the dual boundary theory). We pay special attention to the case D = 4, where module mixings occur in the dual field theory and subtlety arises in the one-loop computation. The results provide evidence that the theory is UV complete and one-loop exact, and we conjecture and provide evidence for a map between the inverse Newton's constant of the partially massless higher-spin theory and the number of colors in the dual CFT.
Partially massless higher-spin theory II: one-loop effective actions
International Nuclear Information System (INIS)
Brust, Christopher; Hinterbichler, Kurt
2017-01-01
We continue our study of a generalization of the D-dimensional linearized Vasiliev higher-spin equations to include a tower of partially massless (PM) fields. We compute one-loop effective actions by evaluating zeta functions for both the “minimal” and “non-minimal” parity-even versions of the theory. Specifically, we compute the log-divergent part of the effective action in odd-dimensional Euclidean AdS spaces for D=7 through 19 (dual to the a-type conformal anomaly of the dual boundary theory), and the finite part of the effective action in even-dimensional Euclidean AdS spaces for D=4 through 8 (dual to the free energy on a sphere of the dual boundary theory). We pay special attention to the case D=4, where module mixings occur in the dual field theory and subtlety arises in the one-loop computation. The results provide evidence that the theory is UV complete and one-loop exact, and we conjecture and provide evidence for a map between the inverse Newton’s constant of the partially massless higher-spin theory and the number of colors in the dual CFT.
Li, Xin; Hong, Yifeng; Wang, Jinfang; Liu, Yang; Sun, Xun; Li, Mi
2018-01-01
Numerous communication techniques and optical devices successfully applied in space optical communication system indicates a good portability of it. With this good portability, typical coherent demodulation technique of Costas loop can be easily adopted in space optical communication system. As one of the components of pointing error, the effect of jitter plays an important role in the communication quality of such system. Here, we obtain the probability density functions (PDF) of different jitter degrees and explain their essential effect on the bit error rate (BER) space optical communication system. Also, under the effect of jitter, we research the bit error rate of space coherent optical communication system using Costas loop with different system parameters of transmission power, divergence angle, receiving diameter, avalanche photodiode (APD) gain, and phase deviation caused by Costas loop. Through a numerical simulation of this kind of communication system, we demonstrate the relationship between the BER and these system parameters, and some corresponding methods of system optimization are presented to enhance the communication quality.
The one-loop effects in the electroweak Glashow-Weinberg-Salam theory
International Nuclear Information System (INIS)
Christova Christova, P.
1987-01-01
In the near future the experiment will reach a great precision and will be able to test the standard electroweak theory. It is important now to put in order calculations of radiative corrections in this theory and to make correct and exact present theoretical predictions for the measured quantities. The survey of some results of group working in the JINR, Dubna, may serve this aim. We discuss here on-mass-shell renormalization scheme in the unitary gauge; the one-loop amplitudes of both charge and neutral currents-induced fermion scatterings; the large constant effects; the dynamical behaviour of the one-loop neutral-current corrections; the calculation of the W-and Z-boson masses; the difference between the various Weinberg parameters sin 2 Θ W . 44 refs., 10 figs., 1 tab. (author)
Effect of External Pressure Drop on Loop Heat Pipe Operating Temperature
Jentung, Ku; Ottenstein, Laura; Rogers, Paul; Cheung, Kwok; Obenschain, Arthur F. (Technical Monitor)
2002-01-01
This paper discusses the effect of the pressure drop on the operating temperature in a loop heat pipe (LHP). Because the evaporator and the compensation chamber (CC) both contain two-phase fluid, a thermodynamic constraint exists between the temperature difference and the pressure drop for these two components. As the pressure drop increases, so will the temperature difference. The temperature difference in turn causes an increase of the heat leak from the evaporator to the CC, resulting in a higher CC temperature. Furthermore, the heat leak strongly depends on the vapor void fraction inside the evaporator core. Tests were conducted by installing a valve on the vapor line so as to vary the pressure drop, and by charging the LHP with various amounts of fluid. Test results verify that the LHP operating temperature increases with an increasing differential pressure, and the temperature increase is a strong function of the fluid inventory in the loop.
International Nuclear Information System (INIS)
Martin, Stephen P.
2003-01-01
I present a method for accurately calculating the pole mass of the lightest Higgs scalar boson in supersymmetric extensions of the standard model, using a mass-independent renormalization scheme. The Higgs scalar self-energies are approximated by supplementing the exact one-loop results with the second derivatives of the complete two-loop effective potential in Landau gauge. I discuss the dependence of this approximation on the choice of renormalization scale, and note the existence of particularly poor choices, which fortunately can be easily identified and avoided. For typical input parameters, the variation in the calculated Higgs boson mass over a wide range of renormalization scales is found to be of the order of a few hundred MeV or less, and is significantly improved over previous approximations
Sharei Amarghan, H.; Alderliesten, Tanja; van den Dobbelsteen, J.J.; Dankelman, J.
2018-01-01
Guidewires and catheters are used during minimally invasive interventional procedures to traverse in vascular system and access the desired position. Computer models are increasingly being used to predict the behavior of these instruments. This information can be used to choose the right
Vortex loops in the critical Casimir effect in superfluid and superconducting films
International Nuclear Information System (INIS)
Williams, Gary A.
2004-01-01
Vortex-loop renormalization techniques are used to calculate the magnitude of the critical Casimir forces in superfluid and superconducting thin films. The force is found to become appreciable when the size of the thermally excited vortex loops is comparable to the film thickness, and the results for T c are found to match very well with perturbative renormalization-group theories that can only be carried out for T>T c . In helium films the Casimir force leads to a change in the film thickness close to T c that has been observed experimentally. A similar effect is predicted to occur near the transition temperature of high-T c superconducting films, which is also a vortex-loop phase transition. In this case the Casimir force takes the form of a voltage difference that will appear at the junction between a thin film and a bulk sample. Estimates show that this voltage can be appreciable (tens of microvolts), and it may be possible to observe the effect by measuring the voltage across two Josephson tunnel junctions to the film and to the bulk, using a SQUID voltmeter
Anatomy of One-Loop Effective Action in Noncommutative Scalar Field Theories
Kiem, Youngjai; Sato, Haru-Tada; Yee, Jung-Tay; Kiem, Youngjai; Rey, Soo-Jong; Sato, Haru-Tada; Yee, Jung-Tay
2002-01-01
One-loop effective action of noncommutative scalar field theory with cubic self-interaction is studied. Utilizing worldline formulation, both planar and nonplanar part of the effective action are computed explicitly. We find complete agreement of the result with Seiberg-Witten limit of string worldsheet computation and standard Feynman diagrammatics. We prove that, at low-energy and large noncommutativity limit, nonplanar part of the effective action is simplified enormously and is resummable into a quadratic action of scalar open Wilson line operators.
In-Out Formalism for One-Loop Effective Actions in QED and Gravity
Kim, S. P.
2017-03-01
The in-out formalism is a systematic and powerful method for finding the effective actions in an electromagnetic field and a curved spacetime provided that the field equation has explicitly known solutions. The effective action becomes complex when pairs of charged particles are produced due to an electric field and curved spacetime. This may lead to a conjecture of one-to-one correspondence between the vacuum polarization (real part) and the vacuum persistence (imaginary part). We illustrate the one-loop effective action in a constant electric field in a Minkowski spacetime and in a uniform electric field in a two-dimensional (anti-) de Sitter space.
The Effective Field Theory of Large Scale Structures at Two Loops
Carrasco, John Joseph M.; Green, Daniel; Senatore, Leonardo
2014-01-01
Large scale structure surveys promise to be the next leading probe of cosmological information. It is therefore crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbation theory for the weakly non-linear regime of dark matter, where correlation functions are computed in an expansion of the wavenumber k of a mode over the wavenumber associated with the non-linear scale k_nl. Since most of the information is contained at high wavenumbers, it is necessary to compute higher order corrections to correlation functions. After the one-loop correction to the matter power spectrum, we estimate that the next leading one is the two-loop contribution, which we compute here. At this order in k/k_nl, there is only one counterterm in the EFTofLSS that must be included, though this term contributes both at tree-level and in several one-loop diagrams. We also discuss correlation functions involving the velocity and momentum fields...
The one-loop five-graviton amplitude and the effective action
International Nuclear Information System (INIS)
Richards, David M.
2008-01-01
We consider the one-loop five-graviton amplitude in type II string theory calculated in the light-cone gauge. Although it is not possible explicitly to evaluate the integrals over the positions of the vertex operators, a low-energy expansion can be obtained, which can then be used to infer terms in the low-energy effective action. After subtracting diagrams due to known D 2n R 4 terms, we show the absence of one-loop R 5 and D 2 R 5 terms and determine the exact structure of the one-loop D 4 R 5 terms where, interestingly, the coefficient in front of the D 4 R 5 terms is identical to the coefficient in front of the D 6 R 4 term. Finally, we show that, up to D 6 R 4 ∼ D 4 R 5 , the ε 10 terms package together with the t 8 terms in the usual combination (t 8 t 8 ± (1/8)ε 10 ε 10 ).
The Effective Field Theory of Large Scale Structures at two loops
International Nuclear Information System (INIS)
Carrasco, John Joseph M.; Foreman, Simon; Green, Daniel; Senatore, Leonardo
2014-01-01
Large scale structure surveys promise to be the next leading probe of cosmological information. It is therefore crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbation theory for the weakly non-linear regime of dark matter, where correlation functions are computed in an expansion of the wavenumber k of a mode over the wavenumber associated with the non-linear scale k NL . Since most of the information is contained at high wavenumbers, it is necessary to compute higher order corrections to correlation functions. After the one-loop correction to the matter power spectrum, we estimate that the next leading one is the two-loop contribution, which we compute here. At this order in k/k NL , there is only one counterterm in the EFTofLSS that must be included, though this term contributes both at tree-level and in several one-loop diagrams. We also discuss correlation functions involving the velocity and momentum fields. We find that the EFTofLSS prediction at two loops matches to percent accuracy the non-linear matter power spectrum at redshift zero up to k∼ 0.6 h Mpc −1 , requiring just one unknown coefficient that needs to be fit to observations. Given that Standard Perturbation Theory stops converging at redshift zero at k∼ 0.1 h Mpc −1 , our results demonstrate the possibility of accessing a factor of order 200 more dark matter quasi-linear modes than naively expected. If the remaining observational challenges to accessing these modes can be addressed with similar success, our results show that there is tremendous potential for large scale structure surveys to explore the primordial universe
Three-loop Standard Model effective potential at leading order in strong and top Yukawa couplings
Energy Technology Data Exchange (ETDEWEB)
Martin, Stephen P. [Santa Barbara, KITP
2014-01-08
I find the three-loop contribution to the effective potential for the Standard Model Higgs field, in the approximation that the strong and top Yukawa couplings are large compared to all other couplings, using dimensional regularization with modified minimal subtraction. Checks follow from gauge invariance and renormalization group invariance. I also briefly comment on the special problems posed by Goldstone boson contributions to the effective potential, and on the numerical impact of the result on the relations between the Higgs vacuum expectation value, mass, and self-interaction coupling.
Heit, Jeremy J; Wong, Johnny Hy; Mofaff, Adrienne M; Telischak, Nicholas A; Dodd, Robert L; Marks, Michael P; Do, Huy M
2018-04-01
Neurointerventional surgeries (NIS) benefit from supportive endovascular constructs. Sofia is a soft-tipped, flexible, braided single lumen intermediate catheter designed for NIS. Sofia advancement from the cervical to the intracranial circulation without a luminal guidewire or microcatheter construct has not been described. To evaluate the efficacy and safety of the new Sofia Non-wire Advancement techniKE (SNAKE) for advancement of the Sofia into the cerebral circulation. Consecutive patients who underwent NIS using Sofia were identified. Patient information, SNAKE use, and patient outcome were determined from electronic medical records. Sofia advancement to the cavernous internal carotid artery or the V2/V3 segment junction of the vertebral artery was the primary outcome measure. Secondary outcomes included arterial vasospasm and arterial dissection. 263 Patients (181 females, 69%) who underwent a total of 305 NIS using Sofia were identified. SNAKE (SNAKE+) was used in 187 procedures (61%). Two hundred and ninety-three procedures (96%) were technically successful, which included 184 SNAKE+ NIS and 109 SNAKE- NIS. Primary outcome was achieved in all SNAKE+ procedures, but not in five SNAKE- procedures (2%). No arterial dissections were identified among 305 interventions. In the intracranial circulation, a single SNAKE+ patient (0.5%) had non-flow limiting arterial vasospasm involving the petrous internal carotid. Three SNAKE+ patients (1.6%) and one SNAKE- patient (0.8%) demonstrated external carotid artery branch artery vasospasm during dural arteriovenous fistula or facial arteriovenous malformation treatment. SNAKE is a safe and effective technique for Sofia advancement. Sofia is a highly effective and safe intermediate catheter for a variety of NIS. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Non-singular bounce scenarios in loop quantum cosmology and the effective field description
International Nuclear Information System (INIS)
Cai, Yi-Fu; Wilson-Ewing, Edward
2014-01-01
A non-singular bouncing cosmology is generically obtained in loop quantum cosmology due to non-perturbative quantum gravity effects. A similar picture can be achieved in standard general relativity in the presence of a scalar field with a non-standard kinetic term such that at high energy densities the field evolves into a ghost condensate and causes a non-singular bounce. During the bouncing phase, the perturbations can be stabilized by introducing a Horndeski operator. Taking the matter content to be a dust field and an ekpyrotic scalar field, we compare the dynamics in loop quantum cosmology and in a non-singular bouncing effective field model with a non-standard kinetic term at both the background and perturbative levels. We find that these two settings share many important properties, including the result that they both generate scale-invariant scalar perturbations. This shows that some quantum gravity effects of the very early universe may be mimicked by effective field models
A covariant technique for the calculation of the one-loop effective action
International Nuclear Information System (INIS)
Avramidi, I.G.
1991-01-01
We develop a manifestly covariant technique for a heat kernel calculation in the presence of arbitrary background fields in a curved space. The four lowest-order coefficients of the Schwinger-De Witt asymptotic expansion are explicitly computed. We also calculate the heat kernel asymptotic expansion up to terms of third order in rapidly varying background fields (curvatures). This approximate series is summed and covariant nonlocal expressions for the heat kernel, ξ-function and one-loop effective action are obtained. Other related problems are discussed. (orig.)
D-instanton and polyinstanton effects from type I' D0-brane loops
Petersson, Christoffer; Uranga, Angel M
2010-01-01
We study non-perturbative D(-1)-instanton corrections to quartic gauge and curvature couplings in 8d type IIB orientifolds, in terms of a one-loop computation of BPS D0-branes in T-dual type I' models. The complete perturbative and non-perturbative results are determined by the BPS multiplicities of perturbative open strings and D0-brane bound states in the 9d type I' theory. Its modular properties admit a geometric interpretation by lifting to Horava-Witten theory. We use the type I' viewpoint to motivate a proper interpretation of 8d and 4d polyinstanton effects, consistent with heterotic - type II orientifold duality.
Li, Di; Yang, Ya; Tian, Zhiqiang; Lv, Jun; Sun, Fengjun; Wang, Qian; Liu, Yao; Xia, Peiyuan
2017-08-22
The treatment of drug-resistant infections is complicated and the alarming rise in infectious diseases poses a unique challenge for development of effective therapeutic strategies. Antibiotic-induced liberation of the bacterial endotoxin lipopolysaccharide (LPS) may have immediate adverse effects promoting septic shock in patients. In the present study, we first confirmed our previous finding that looped antimicrobial peptide CLP-19 exerts non-specific direct antibacterial activity with no toxic to mammalian cells and second revealed that CLP-19 has synergistic effect to enhance the antibacterial activities of other conventional bactericidal (ampicillin and ceftazidime) and bacteriostatic (erythromycin and levofloxacin) agents. Third, the underlying mechanism of antibiotic effect was likely associated with stimulation of hydroxyl radical generation. Lastly, CLP-19 was shown to effectively reduce the antibiotic-induced liberation of LPS, through direct neutralization of the LPS. Thus, CLP-19 is a potential therapeutic agent for combinatorial antibiotic therapy.
Discreteness corrections to the effective Hamiltonian of isotropic loop quantum cosmology
Energy Technology Data Exchange (ETDEWEB)
Banerjee, Kinjal; Date, Ghanashyam [Institute of Mathematical Sciences, CIT Campus, Chennai 600 113 (India)
2005-06-07
One of the qualitatively distinct and robust implications of loop quantum gravity is the underlying discrete structure. In the cosmological context elucidated by loop quantum cosmology, this is manifested by the Hamiltonian constraint equation being a (partial) difference equation. One obtains an effective Hamiltonian framework by making the continuum approximation followed by a WKB approximation. In the large volume regime, these lead to the usual classical Einstein equation which is independent of both the Barbero-Immirzi parameter {gamma} as well as {Dirac_h}. In this work, we present an alternative derivation of the effective Hamiltonian by-passing the continuum approximation step. As a result, the effective Hamiltonian is obtained as a closed form expression in {gamma}. These corrections to the Einstein equation can be thought of as corrections due to the underlying discrete (spatial) geometry with {gamma} controlling the size of these corrections. These corrections imply a bound on the rate of change of the volume of the isotropic universe. In most cases these are perturbative in nature but for a cosmological constant dominated isotropic universe, there are significant deviations.
Static and Dynamic Pricing Strategies in a Closed-Loop Supply Chain with Reference Quality Effects
Directory of Open Access Journals (Sweden)
Zhichao Zhang
2018-01-01
Full Text Available Remanufacturing of returned products has been increasingly recognized in industries as an effective approach to face environmental responsibility, government regulations, and increased awareness of consumers. In this paper, we address a closed-loop supply chain (CLSC in which the manufacturer produces the brand-new products, as well as the remanufactured goods while the retailer sells these products to customers. We consider several different scenarios: the manufacturer and the retailer adopt a steady-state price or a dynamic price with reference quality effects in a centralized case; either, neither or both the manufacturer and the retailer price dynamically with reference quality effects, respectively, in a decentralized model. We solve the problem with the retailer recycling the sold copies and deduce the optimal pricing strategies while the manufacturer in charge of recovering the used items in such a CLSC. The result shows that dynamic pricing strategies are much more profitable for the supply chain and its members when compared with pricing statically; the dynamic pricing strategies with time-varying quality characterized by reference quality are more suited to a long-term and cooperative closed-loop supply chain. Moreover, the optimal recycling fraction relies on the recovery cost coefficient and proves to be uniform despite adopting a dynamic price and quality in all distinct cases.
Infrared divergences and harmonic anomalies in the two-loop superstring effective action
Pioline, Boris
2015-01-01
We analyze the pertubative contributions to the $D^4 R^4$ and $D^6 R^4$ couplings in the low-energy effective action of type II string theory compactified on a torus $T^d$, with particular emphasis on two-loop corrections. In general, it is necessary to introduce an infrared cut-off $\\Lambda$ to separate local interactions from non-local effects due to the exchange of massless states. We identify the degenerations of the genus-two Riemann surface which are responsible for power-like dependence on $\\Lambda$, and give an explicit prescription for extracting the $\\Lambda$-independent effective couplings. These renormalized couplings are then shown to be eigenmodes of the Laplace operator with respect to the torus moduli, up to computable anomalous source terms arising in the presence of logarithmic divergences, in precise agreement with predictions from U-duality. Our results for the two-loop $D^6 R^4$ contribution also probe essential properties of the Kawazumi-Zhang invariant
Loop corrections and other many-body effects in relativistic field theories
International Nuclear Information System (INIS)
Ainsworth, T.L.; Brown, G.E.; Prakash, M.; Weise, W.
1988-01-01
Incorporation of effective masses into negative energy states (nucleon loop corrections) gives rise to repulsive many-body forces, as has been known for some time. Rather than renormalizing away the three- and four-body terms, we introduce medium corrections into the effective σ-exchange, which roughly cancel the nucleon loop terms for densities ρ ≅ ρ nm , where ρ nm is nuclear matter density. Going to higher densities, the repulsive contributions tend to saturate whereas the attractive ones keep on growing in magnitude. The latter is achieved through use of a density-dependent effective mass for the σ-particle, m σ = m σ (ρ), such that m σ (ρ) decreases with increasing density. Such a behavior is seen e.g. in the Nambu-Jona-Lasinio model. It is argued that a smooth transition to chiral restoration implies a similar behavior. The resulting nuclear equation of state is, because of the self-consistency in the problem, immensely insensitive to changes in the mass or coupling constant of the σ-particle. (orig.)
Infrared divergences and harmonic anomalies in the two-loop superstring effective action
Energy Technology Data Exchange (ETDEWEB)
Pioline, Boris [CERN PH-TH,Case C01600, CERN, CH-1211 Geneva 23 (Switzerland); Sorbonne Universités,UPMC Université Paris 6, UMR 7589, F-75005 Paris (France); Laboratoire de Physique Théorique et Hautes Energies, CNRS UMR 7589,Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris cedex 05 (France); Russo, Rodolfo [Centre for Research in String Theory, School of Physics and Astronomy,Queen Mary University of London, Mile End Road, London, E1 4NS (United Kingdom)
2015-12-16
We analyze the pertubative contributions to the D{sup 4}R{sup 4} and D{sup 6}R{sup 4} couplings in the low-energy effective action of type II string theory compactified on a torus T{sup d}, with particular emphasis on two-loop corrections. In general, it is necessary to introduce an infrared cut-off Λ to separate local interactions from non-local effects due to the exchange of massless states. We identify the degenerations of the genus-two Riemann surface which are responsible for power-like dependence on Λ, and give an explicit prescription for extracting the Λ-independent effective couplings. These renormalized couplings are then shown to be eigenmodes of the Laplace operator with respect to the torus moduli, up to computable anomalous source terms arising in the presence of logarithmic divergences, in precise agreement with predictions from U-duality. Our results for the two-loop D{sup 6}R{sup 4} contribution also probe essential properties of the Kawazumi-Zhang invariant.
Kos, Sebastian; Huegli, Rolf; Hofmann, Eugen; Quick, Harald H; Kuehl, Hilmar; Aker, Stephanie; Kaiser, Gernot M; Borm, Paul J A; Jacob, Augustinus L; Bilecen, Deniz
2009-05-01
The purpose of this study was to demonstrate feasibility of percutaneous transluminal aortic stenting and cava filter placement under magnetic resonance imaging (MRI) guidance exclusively using a polyetheretherketone (PEEK)-based MRI-compatible guidewire. Percutaneous transluminal aortic stenting and cava filter placement were performed in 3 domestic swine. Procedures were performed under MRI-guidance in an open-bore 1.5-T scanner. The applied 0.035-inch guidewire has a PEEK core reinforced by fibres, floppy tip, hydrophilic coating, and paramagnetic markings for passive visualization. Through an 11F sheath, the guidewire was advanced into the abdominal (swine 1) or thoracic aorta (swine 2), and the stents were deployed. The guidewire was advanced into the inferior vena cava (swine 3), and the cava filter was deployed. Postmortem autopsy was performed. Procedural success, guidewire visibility, pushability, and stent support were qualitatively assessed by consensus. Procedure times were documented. Guidewire guidance into the abdominal and thoracic aortas and the inferior vena cava was successful. Stent deployments were successful in the abdominal (swine 1) and thoracic (swine 2) segments of the descending aorta. Cava filter positioning and deployment was successful. Autopsy documented good stent and filter positioning. Guidewire visibility through applied markers was rated acceptable for aortic stenting and good for venous filter placement. Steerability, pushability, and device support were good. The PEEK-based guidewire allows either percutaneous MRI-guided aortic stenting in the thoracic and abdominal segments of the descending aorta and filter placement in the inferior vena cava with acceptable to good device visibility and offers good steerability, pushability, and device support.
International Nuclear Information System (INIS)
Kos, Sebastian; Huegli, Rolf; Hofmann, Eugen; Quick, Harald H.; Kuehl, Hilmar; Aker, Stephanie; Kaiser, Gernot M.; Borm, Paul J. A.; Jacob, Augustinus L.; Bilecen, Deniz
2009-01-01
The purpose of this study was to demonstrate feasibility of percutaneous transluminal aortic stenting and cava filter placement under magnetic resonance imaging (MRI) guidance exclusively using a polyetheretherketone (PEEK)-based MRI-compatible guidewire. Percutaneous transluminal aortic stenting and cava filter placement were performed in 3 domestic swine. Procedures were performed under MRI-guidance in an open-bore 1.5-T scanner. The applied 0.035-inch guidewire has a PEEK core reinforced by fibres, floppy tip, hydrophilic coating, and paramagnetic markings for passive visualization. Through an 11F sheath, the guidewire was advanced into the abdominal (swine 1) or thoracic aorta (swine 2), and the stents were deployed. The guidewire was advanced into the inferior vena cava (swine 3), and the cava filter was deployed. Postmortem autopsy was performed. Procedural success, guidewire visibility, pushability, and stent support were qualitatively assessed by consensus. Procedure times were documented. Guidewire guidance into the abdominal and thoracic aortas and the inferior vena cava was successful. Stent deployments were successful in the abdominal (swine 1) and thoracic (swine 2) segments of the descending aorta. Cava filter positioning and deployment was successful. Autopsy documented good stent and filter positioning. Guidewire visibility through applied markers was rated acceptable for aortic stenting and good for venous filter placement. Steerability, pushability, and device support were good. The PEEK-based guidewire allows either percutaneous MRI-guided aortic stenting in the thoracic and abdominal segments of the descending aorta and filter placement in the inferior vena cava with acceptable to good device visibility and offers good steerability, pushability, and device support.
One-loop effect of null-like cosmology's holographic dual super-Yang-Mills
International Nuclear Information System (INIS)
Lin, F.-L.; Tomino, Dan
2007-01-01
We calculate the 1-loop effect in super-Yang-Mills which preserves 1/4-supersymmetries and is holographically dual to the null-like cosmology with a big-bang singularity. Though the bosonic and fermionic spectra do not agree precisely, we do obtain vanishing 1-loop vacuum energy for generic warped plane-wave type backgrounds with a big-bang singularity. Moreover, we find that the cosmological 'constant' contributed either by bosons or fermions is time-dependent. The issues about the particle production of some background and about the UV structure are also commented. We argue that the effective higher derivative interactions are suppressed as long as the Fourier transform of the time-dependent coupling is UV-finite. Our result holds for scalar configurations that are BPS but with arbitrary time-dependence. This suggests the existence of non-renormalization theorem for such a new class of time-dependent theories. Altogether, it implies that such a super-Yang-Mills is scale-invariant, and that its dual bulk quantum gravity might behave regularly near the big bang
The effects of Kelvin-Helmholtz instability on resonance absorption layers in coronal loops
Karpen, Judith T.; Dahlburg, Russell B.; Davila, Joseph M.
1994-01-01
One of the long-standing uncertainties in the wave-resonance theory of coronal heating is the stability of the resonance layer. The wave motions in the resonance layer produce highly localized shear flows which vary sinusoidally in time with the resonance period. This configuration is potentially susceptible to the Kelvin-Helmholtz instability (KHI), which can enhance small-scale structure and turbulent broadening of shear layers on relatively rapid ideal timescales. We have investigated numerically the response of a characteristic velocity profile, derived from resonance absorption models, to finite fluid perturbations comparable to photospheric fluctuations. We find that the KHI primarily should affect long (approximately greater than 6 x 10(exp 4) km) loops where higher velocity flows (M approximately greater than 0.2) exist in resonance layers of order 100 km wide. There, the Kelvin-Helmholtz growth time is comparable to or less than the resonance quarter-period, and the potentially stabilizing magnetic effects are not felt until the instability is well past the linear growth stage. Not only is the resonance layer broadened by the KHI, but also the convective energy transport out of the resonance layer is increased, thus adding to the efficiency of the wave-resonance heating process. In shorter loops, e.g., those in bright points and compact flares, the stabilization due to the magnetic field and the high resonance frequency inhibit the growth of the Kelvin-Helmholtz instability beyond a minimal level.
Two-loop scale-invariant scalar potential and quantum effective operators
Ghilencea, D.M.
2016-11-29
Spontaneous breaking of quantum scale invariance may provide a solution to the hierarchy and cosmological constant problems. In a scale-invariant regularization, we compute the two-loop potential of a higgs-like scalar $\\phi$ in theories in which scale symmetry is broken only spontaneously by the dilaton ($\\sigma$). Its vev $\\langle\\sigma\\rangle$ generates the DR subtraction scale ($\\mu\\sim\\langle\\sigma\\rangle$), which avoids the explicit scale symmetry breaking by traditional regularizations (where $\\mu$=fixed scale). The two-loop potential contains effective operators of non-polynomial nature as well as new corrections, beyond those obtained with explicit breaking ($\\mu$=fixed scale). These operators have the form: $\\phi^6/\\sigma^2$, $\\phi^8/\\sigma^4$, etc, which generate an infinite series of higher dimensional polynomial operators upon expansion about $\\langle\\sigma\\rangle\\gg \\langle\\phi\\rangle$, where such hierarchy is arranged by {\\it one} initial, classical tuning. These operators emerge at the quantum...
One-loop light-cone QCD, effective action for reggeized gluons and QCD RFT calculus
Bondarenko, S.; Lipatov, L.; Pozdnyakov, S.; Prygarin, A.
2017-09-01
The effective action for reggeized gluons is based on the gluodynamic Yang-Mills Lagrangian with external current for longitudinal gluons added, see Lipatov (Nucl Phys B 452:369, 1995; Phys Rep 286:131, 1997; Subnucl Ser 49:131, 2013; Int J Mod Phys Conf Ser 39:1560082, 2015; Int J Mod Phys A 31(28/29):1645011, 2016; EPJ Web Conf 125:01010, 2016). On the base of classical solutions, obtained in Bondarenko et al. (Eur Phys J C 77(8):527, 2017), the one-loop corrections to this effective action in light-cone gauge are calculated. The RFT calculus for reggeized gluons similarly to the RFT introduced in Gribov (Sov Phys JETP 26:414, 1968) is proposed and discussed. The correctness of the results is verified by calculation of the propagators of A+ and A- reggeized gluons fields and application of the obtained results is discussed as well.
Two-loop dimensional reduction and effective potential without temperature expansions
Laine, Mikko
2000-01-01
In many extensions of the Standard Model, finite temperature computations are complicated by a hierarchy of zero temperature mass scales, in addition to the usual thermal mass scales. We extend the standard thermal resummations to such a situation, and discuss the 2-loop computations of the Higgs effective potential, and an effective 3d field theory for the electroweak phase transition, without carrying out high or low temperature expansions for the heavy masses. We also estimate the accuracy of the temperature expansions previously used for the MSSM electroweak phase transition in the presence of a heavy left-handed stop. We find that the low temperature limit of dealing with the left-handed stop is accurate up to surprisingly high temperatures.
Two-loop dimensional reduction and effective potential without temperature expansions
Laine, M.; Losada, M.
2000-08-01
In many extensions of the Standard Model, finite temperature computations are complicated by a hierarchy of zero temperature mass scales, in addition to the usual thermal mass scales. We extend the standard thermal resummations to such a situation, and discuss the 2-loop computations of the Higgs effective potential, and an effective 3d field theory for the electroweak phase transition, without carrying out high or low temperature expansions for the heavy masses. We also estimate the accuracy of the temperature expansions previously used for the MSSM electroweak phase transition in the presence of a heavy left-handed stop. We find that the low temperature limit of dealing with the left-handed stop is accurate up to surprisingly high temperatures.
Hoshino, Taro; Ookawara, Susumu; Miyazawa, Haruhisa; Ito, Kiyonori; Ueda, Yuichiro; Kaku, Yoshio; Hirai, Keiji; Mori, Honami; Yoshida, Izumi; Tabei, Kaoru
2015-04-01
Type 2 diabetic kidney disease (DKD) is frequently accompanied by uncontrollable hypertension due to the sodium sensitivity inherent in DKD and to diuretic-resistant edema. In general, diuretics are effective in treating this condition, but thiazide diuretics are thought to be innocuous in advanced chronic kidney disease (CKD). We examined the renoprotective effects of combination therapy with thiazides and loop diuretics in type 2 DKD patients with CKD stage G4 or G5. This study included 11 patients with type 2 DKD and an estimated glomerular filtration rate (eGFR) diuretics. Each patient received additional hydrochlorothiazide (HCTZ) therapy, which was continued for more than 12 months. We examined clinical parameters including blood pressure (BP), proteinuria, and eGFR before and after the addition of HCTZ. Patients received a 13.6 ± 3.8 mg/day dose of HCTZ in addition to loop diuretics (azosemide: 120 mg/day in 6 cases, 60 mg/day in 3 cases and furosemide: 80 mg/day in 1 case, 120 mg/day in 1 case). Side effects of HCTZ were not observed in all patients. After the addition of HCTZ therapy, systolic and diastolic blood pressures (S-BP, D-BP) as well as proteinuria significantly decreased (S-BP: at 6 months, p diuretics improves BP levels, and decreases proteinuria even in advanced stage type 2 DKD patients with severe edema. The addition of HCTZ therapy was not found to negatively affect the change in eGFR in the present study.
One-loop effective Lagrangian for a standard model with a heavy charged scalar singlet
Bilenky, S M; Bilenky, Mikhail; Santamaria, Arcadi
1994-01-01
We study several problems related to the construction and the use of effective Lagrangians by considering an extension of the standard model that includes a heavy scalar singlet coupled to the leptonic doublet. Starting from the full renormalizable model, we build an effective field theory by integrating out the heavy scalar. A local effective Lagrangian (up to operators of dimension six) is obtained by expanding the one-loop effective action in inverse powers of the heavy mass. This is done by matching some Green functions calculated with both the full and the effective theories. Using this simple example we study the renormalization of effective Lagrangians in general and discuss how they can be used to bound new physics. We also discuss the effective Lagrangian after spontaneous symmetry breaking, and the use of the standard model classical equations of motion to rewrite it in different forms. The final effective Lagrangian in the physical basis is well suited to the study of the phenomenology of the model...
International Nuclear Information System (INIS)
Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju; Wirstam, Jens
2000-01-01
The one loop effective action in quantum field theory can be expressed as a quantum mechanical path integral over world lines, with internal symmetries represented by Grassmanian variables. In this paper, we develop a real time, many body, world line formalism for the one loop effective action. In particular, we study hot QCD and obtain the classical transport equations which, as Litim and Manuel have shown, reduce in the appropriate limit to the non-Abelian Boltzmann-Langevin equation first obtained by Boedeker. In the Vlasov limit, the classical kinetic equations are those that correspond to the hard thermal loop effective action. We also discuss the imaginary time world line formalism for a hot φ 4 theory, and elucidate its relation to classical transport theory. (c) 2000 The American Physical Society
The one-loop matter bispectrum in the Effective Field Theory of Large Scale Structures
Energy Technology Data Exchange (ETDEWEB)
Angulo, Raul E. [Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta-2, 44001, Teruel (Spain); Foreman, Simon; Senatore, Leonardo [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA 94306 (United States); Schmittfull, Marcel, E-mail: rangulo@cefca.es, E-mail: sfore@stanford.edu, E-mail: mschmittfull@lbl.gov, E-mail: senatore@stanford.edu [Berkeley Center for Cosmological Physics, Department of Physics, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
2015-10-01
Given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme to compute the clustering of dark matter in the weakly nonlinear regime in an expansion in k/k{sub NL}, where k is the wavenumber of interest and k{sub NL} is the wavenumber associated to the nonlinear scale. It has been recently shown that the EFTofLSS matches to 1% level the dark matter power spectrum at redshift zero up to k≅ 0.3 h Mpc{sup −1} and k≅ 0.6 h Mpc{sup −1} at one and two loops respectively, using only one counterterm that is fit to data. Similar results have been obtained for the momentum power spectrum at one loop. This is a remarkable improvement with respect to former analytical techniques. Here we study the prediction for the equal-time dark matter bispectrum at one loop. We find that at this order it is sufficient to consider the same counterterm that was measured in the power spectrum. Without any remaining free parameter, and in a cosmology for which k{sub NL} is smaller than in the previously considered cases (σ{sub 8}=0.9), we find that the prediction from the EFTofLSS agrees very well with N-body simulations up to k≅ 0.25 h Mpc{sup −1}, given the accuracy of the measurements, which is of order a few percent at the highest k's of interest. While the fit is very good on average up to k≅ 0.25 h Mpc{sup −1}, the fit performs slightly worse on equilateral configurations, in agreement with expectations that for a given maximum k, equilateral triangles are the most nonlinear.
Zhu, Tao; Wang, Anzhong; Kirsten, Klaus; Cleaver, Gerald; Sheng, Qin
2018-02-01
Loop quantum cosmology provides a resolution of the classical big bang singularity in the deep Planck era. The evolution, prior to the usual slow-roll inflation, naturally generates excited states at the onset of the slow-roll inflation. It is expected that these quantum gravitational effects could leave its fingerprints on the primordial perturbation spectrum and non-Gaussianity, and lead to some observational evidences in the cosmic microwave background. While the impact of the quantum effects on the primordial perturbation spectrum has been already studied and constrained by current data, in this paper we continue to study such effects but now on the non-Gaussianity of the primordial curvature perturbations. We present detailed and analytical calculations of the non-Gaussianity and show explicitly that the corrections due to the quantum effects are at the same magnitude of the slow-roll parameters in the observable scales and thus are well within current observational constraints. Despite this, we show that the non-Gaussianity in the squeezed limit can be enhanced at superhorizon scales and it is these effects that can yield a large statistical anisotropy on the power spectrum through the Erickcek-Kamionkowski-Carroll mechanism.
The ξ/ξ2nd ratio as a test for Effective Polyakov Loop Actions
Caselle, Michele; Nada, Alessandro
2018-03-01
Effective Polyakov line actions are a powerful tool to study the finite temperature behaviour of lattice gauge theories. They are much simpler to simulate than the original (3+1) dimensional LGTs and are affected by a milder sign problem. However it is not clear to which extent they really capture the rich spectrum of the original theories, a feature which is instead of great importance if one aims to address the sign problem. We propose here a simple way to address this issue based on the so called second moment correlation length ξ2nd. The ratio ξ/ξ2nd between the exponential correlation length and the second moment one is equal to 1 if only a single mass is present in the spectrum, and becomes larger and larger as the complexity of the spectrum increases. Since both ξexp and ξ2nd are easy to measure on the lattice, this is an economic and effective way to keep track of the spectrum of the theory. In this respect we show using both numerical simulation and effective string calculations that this ratio increases dramatically as the temperature decreases. This non-trivial behaviour should be reproduced by the Polyakov loop effective action.
The ξ/ξ2nd ratio as a test for Effective Polyakov Loop Actions
Directory of Open Access Journals (Sweden)
Caselle Michele
2018-01-01
Full Text Available Effective Polyakov line actions are a powerful tool to study the finite temperature behaviour of lattice gauge theories. They are much simpler to simulate than the original (3+1 dimensional LGTs and are affected by a milder sign problem. However it is not clear to which extent they really capture the rich spectrum of the original theories, a feature which is instead of great importance if one aims to address the sign problem. We propose here a simple way to address this issue based on the so called second moment correlation length ξ2nd. The ratio ξ/ξ2nd between the exponential correlation length and the second moment one is equal to 1 if only a single mass is present in the spectrum, and becomes larger and larger as the complexity of the spectrum increases. Since both ξexp and ξ2nd are easy to measure on the lattice, this is an economic and effective way to keep track of the spectrum of the theory. In this respect we show using both numerical simulation and effective string calculations that this ratio increases dramatically as the temperature decreases. This non-trivial behaviour should be reproduced by the Polyakov loop effective action.
Petrick, E. J.
1973-01-01
An analytical study was made of the stability of a closed-loop liquid-lithium temperature control of the primary loop of a conceptual nuclear Brayton space powerplant. The operating point was varied from 20 to 120 percent of design. A describing-function technique was used to evaluate the effects of temperature dead band and control coupling backlash. From the system investigation, it was predicted that a limit cycle will not exist with a temperature dead band, but a limit cycle will not exist when backlash is present. The results compare favorably with a digital computer simulation.
Supercoiling Effects on Short-Range DNA Looping in E. coli.
Directory of Open Access Journals (Sweden)
Lauren S Mogil
Full Text Available DNA-protein loops can be essential for gene regulation. The Escherichia coli lactose (lac operon is controlled by DNA-protein loops that have been studied for decades. Here we adapt this model to test the hypothesis that negative superhelical strain facilitates the formation of short-range (6-8 DNA turns repression loops in E. coli. The natural negative superhelicity of E. coli DNA is regulated by the interplay of gyrase and topoisomerase enzymes, adding or removing negative supercoils, respectively. Here, we measured quantitatively DNA looping in three different E. coli strains characterized by different levels of global supercoiling: wild type, gyrase mutant (gyrB226, and topoisomerase mutant (ΔtopA10. DNA looping in each strain was measured by assaying repression of the endogenous lac operon, and repression of ten reporter constructs with DNA loop sizes between 70-85 base pairs. Our data are most simply interpreted as supporting the hypothesis that negative supercoiling facilitates gene repression by small DNA-protein loops in living bacteria.
International Nuclear Information System (INIS)
Armbya, Narain; Li, Guanjun; Chen, Yitung; Moujaes, Samir
2004-01-01
Work is ongoing at UNLV to provide a computer simulation framework that will characterize the behavior and effect of thermalhydraulics on the corrosion/precipitation chemical kinetics processes that take place on the inside surfaces of an LBE flow loop. To that end detailed models are being constructed to study these effects first in several expected loop fittings such as sudden expansion and tee-fittings. The typical flow rates chosen for these simulations are typical of design criteria chosen for the loop with Re numbers expected around 200,000 and the usual axial temperature profiles which are being characterized in the DELTA loop at LANL. STAR-CD is the simulation package used to make these predictions which include detailed 3-D velocity, temperature and concentration gradient profiles of the corrosion/precipitation on the inner surface of these fittings initially. The different predicted variables from these simulations indicate that special attention needs to be placed when designing loops with these fittings especially in the regions of sudden velocity changes and stagnation zones. These wall gradients can determine eventually the expected longevity of these fittings in an LBE flow environment. Presently though very little experimental data exists that would be suitable to corroborate the simulation results. Graphs of concentration gradient v/s distance from the inlet of these fittings were plotted. Eventually these individual fitting models will become part of an overall closed loop that will yield more realistic core concentration values and hence more realistic wall gradient values which are dependent on these core values. (author)
Rizou, Zoe V.; Zoiros, Kyriakos E.; Hatziefremidis, Antonios; Connelly, Michael J.
2015-05-01
In this paper, we analyze the performance of the birefringent fiber loop (BFL) when the settings of the components that construct this module are not perfect. The BFL is employed for suppressing the pattern effect on directly amplified data in a semiconductor optical amplifier (SOA). The analysis is conducted by describing the non-optimum BFL transmission response using Jones matrix method. This allows to formulate a comprehensive model, which is validated by comparing it to the experiment. Then we investigate and specify how sensitive the BFL is to imperfections of its building components by assessing its performance against the output amplitude modulation, power penalty, and crosstalk. For each critical operating parameter, we derive the tolerance range within which these performance metrics are acceptable. The obtained results suggest that the BFL can efficiently mitigate the SOA pattern effect even if it is built from non-ideal components. This can be achieved provided that these components are designed according to their extracted operating conditions, which are practically satisfiable.
One-loop light-cone QCD, effective action for reggeized gluons and QCD RFT calculus
Energy Technology Data Exchange (ETDEWEB)
Bondarenko, S.; Pozdnyakov, S.; Prygarin, A. [Ariel University, Physics Department, Ariel (Israel); Lipatov, L. [St. Petersburg State University, St. Petersburg (Russian Federation); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)
2017-09-15
The effective action for reggeized gluons is based on the gluodynamic Yang-Mills Lagrangian with external current for longitudinal gluons added, see Lipatov (Nucl Phys B 452:369, 1995; Phys Rep 286:131, 1997; Subnucl Ser 49:131, 2013; Int J Mod Phys Conf Ser 39:1560082, 2015; Int J Mod Phys A 31(28/29):1645011, 2016; EPJ Web Conf 125:01010, 2016). On the base of classical solutions, obtained in Bondarenko et al. (Eur Phys J C 77(8):527, 2017), the one-loop corrections to this effective action in light-cone gauge are calculated. The RFT calculus for reggeized gluons similarly to the RFT introduced in Gribov (Sov Phys JETP 26:414, 1968) is proposed and discussed. The correctness of the results is verified by calculation of the propagators of A{sub +} and A{sub -} reggeized gluons fields and application of the obtained results is discussed as well. (orig.)
Three- and two-point one-loop integrals in heavy particle effective theories
International Nuclear Information System (INIS)
Bouzas, A.O.
2000-01-01
We give a complete analytical computation of three- and two-point loop integrals occurring in heavy particle theories, involving a velocity change, for arbitrary real values of the external masses and residual momenta. (orig.)
Nassar, Yasser S; Boudou, Nicolas; Dumonteil, Nicolas; Lhermusier, Thibault; Carrie, Didier
2013-04-01
Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) of the left anterior descending (LAD) specifically is associated with improved long-term 5 year survival as compared to PCI failure. The procedure is associated with usage of different types of dedicated guidewires by simple or complex techniques aiming to reopen the occluded artery. To describe types and outcome of guidewires used in LAD-CTO utilizing a first intentional single wiring simple strategy. A single center prospective registry for all consecutive patients with a PCI attempt to a native LAD CTO. The initial strategy for lesion crossing was Single wiring. A total of 30 patients with LAD CTO lesions (100%), were recorded. Mean age was 71.6 + 15 years, 77% were Males, risk factors Hypertension in 63%, Diabetes 27%, Dyslipidemia 57%, smoking 40%, hereditary in 13% of patients. Isolated guidewire (GW) success rate was very high 93%. Single wiring was the prevailing technique used in 97% of successfull lesions (83% of total cases) while only 3% were by multiple wiring techniques. Successful single antegrade wiring represented 63% with a GW success rate of 92% of cases. Successful single retrograde wiring represented 13% with a GW success rate of 67%. Successful Crossing GW types in our patients were 44% Soft Tapered GWs; fielder XT (44%), 36% were Soft Non Tapered Pilot 50 (28%), whisper (8%), while 16% were Stiff Non tapered GWs; Miracle 12 (8%), Miracle 6 (4%), Miracle 3 (4%), and 4% were Stiff Tapered GWs; Progress 200 (4%). Single wiring as an initial strategy in PCI for LAD-CTO lesions has a high success rate and is associated with a 44% majority of Soft Tapered GWs, 36% Soft Non Tapered, 16% Stiff Non tapered GWs, and 4% Stiff Tapered GWs.
van Duren, B H; Sugand, K; Wescott, R; Carrington, R; Hart, A
2018-05-01
Hip fractures contribute to a significant clinical burden globally with over 1.6 million cases per annum and up to 30% mortality rate within the first year. Insertion of a dynamic hip screw (DHS) is a frequently performed procedure to treat extracapsular neck of femur fractures. Poorly performed DHS fixation of extracapsular neck of femur fractures can result in poor mobilisation, chronic pain, and increased cut-out rate requiring revision surgery. A realistic, affordable, and portable fluoroscopic simulation system can improve performance metrics in trainees, including the tip-apex distance (the only clinically validated outcome), and improve outcomes. We developed a digital fluoroscopic imaging simulator using orthogonal cameras to track coloured markers attached to the guide-wire which created a virtual overlay on fluoroscopic images of the hip. To test the accuracy with which the augmented reality system could track a guide-wire, a standard workshop femur was used to calibrate the system with a positional marker fixed to indicate the apex; this allowed for comparison between guide-wire tip-apex distance (TAD) calculated by the system to be compared to that physically measured. Tests were undertaken to determine: (1) how well the apex could be targeted; (2) the accuracy of the calculated TAD. (3) The number of iterations through the algorithm giving the optimal accuracy-time relationship. The calculated TAD was found to have an average root mean square error of 4.2 mm. The accuracy of the algorithm was shown to increase with the number of iterations up to 20 beyond which the error asymptotically converged to an error of 2 mm. This work demonstrates a novel augmented reality simulation of guide-wire insertion in DHS surgery. To our knowledge this has not been previously achieved. In contrast to virtual reality, augmented reality is able to simulate fluoroscopy while allowing the trainee to interact with real instrumentation and performing the procedure on
Beccaria, M; Renard, F M; Verzegnassi, C
2006-01-01
We compute, in the MSSM framework, the total electroweak contributions at one loop for the process pp -> tW+X, initiated by the parton process bg -> tW. The supersymmetric effect is analyzed for various choices of the SUSY benchmark points. Choosing realistic unpolarized and polarized experimental quantities, we show the size of the various effects and discuss their dependence on the MSSM parameters.
Zhu, X D
2017-08-01
I present a detailed account of a zero loop-area Sagnac interferometer operated at oblique incidence for detecting magneto-optic Kerr effects arising from a magnetized sample. In particular, I describe the symmetry consideration and various optical arrangements available to such an interferometer that enables measurements of magneto-optic effects due to both in-plane and out-of-plane magnetization of the sample with optimizable signal-to-noise ratios.
International Nuclear Information System (INIS)
Tang, F.; Liu, D.-L.; Ye, D.-X.; Lu, T.-M.; Wang, G.-C.
2004-01-01
Magneto-optical Kerr effect (MOKE) in the longitudinal mode was used to measure the in-plane magnetic anisotropy of about 300nm thick Co nano-column films that were grown by e-beam evaporation at different oblique incident angles (0-85 o ) on native SiO 2 substrates at room temperature. The symmetry of MOKE loops measured at azimuthal angles that are 180 o apart is obviously broken for Co nano-column films grown at high deposition angles >70 o . The plot of coercivity H c of loops versus azimuthal angle shows that H c values for azimuthal angles between -90 o and 90 o are much larger than the values for azimuthal angles between 90 o and 270 o . The asymmetry of coercivity is due to MOKE measurement that combines both longitudinal and polar Kerr effects. This combination is caused by the oblique magnetic anisotropy associated with the tilted Co nano-columns. A method is introduced to separate the longitudinal and polar Kerr effects. The longitudinal Kerr effect is obtained by adding hysteresis loops measured at azimuthal angles 180 o apart while the polar Kerr effect is obtained by subtracting these two loops. By comparing these two orthogonal magnetization components represented by longitudinal and polar Kerr effects, we show that magnetization rotation exists in the magnetic reversal process even at azimuthal angle φ=0 o that is the closest in-plane direction to the easy axis. After separating these two Kerr effects, the two-fold symmetry of coervicity associated with tilted nano-columns measured by longitudinal Kerr effect is restored
Tomasello, Salvatore Davide; Giudice, Pietro; Attisano, Tiziana; Boukhris, Marouane; Galassi, Alfredo R
2014-10-01
The treatment of coronary chronic total occlusions (CTO) continues to solicit technical innovations. As success primarily depends on crossing the lesion with a wire, all aspects regarding tip shape retention, torque precision, and penetration ability of the guide-wire have greatly influenced new techniques and strategies. The world of interventional cardiology has to look carefully at these developments, and to use them accordingly to improve the success rate in ordinary percutaneous coronary interventions. We present a didactical case report of a CTO revascularization treated with a new 'dual core' technology guide-wire.
The complete two-loop integrated jet thrust distribution in soft-collinear effective theory
Energy Technology Data Exchange (ETDEWEB)
von Manteuffel, Andreas; Schabinger, Robert M.; Zhu, Hua Xing
2014-03-01
In this work, we complete the calculation of the soft part of the two-loop integrated jet thrust distribution in e+e- annihilation. This jet mass observable is based on the thrust cone jet algorithm, which involves a veto scale for out-of-jet radiation. The previously uncomputed part of our result depends in a complicated way on the jet cone size, r, and at intermediate stages of the calculation we actually encounter a new class of multiple polylogarithms. We employ an extension of the coproduct calculus to systematically exploit functional relations and represent our results concisely. In contrast to the individual contributions, the sum of all global terms can be expressed in terms of classical polylogarithms. Our explicit two-loop calculation enables us to clarify the small r picture discussed in earlier work. In particular, we show that the resummation of the logarithms of r that appear in the previously uncomputed part of the two-loop integrated jet thrust distribution is inextricably linked to the resummation of the non-global logarithms. Furthermore, we find that the logarithms of r which cannot be absorbed into the non-global logarithms in the way advocated in earlier work have coefficients fixed by the two-loop cusp anomalous dimension. We also show that in many cases one can straightforwardly predict potentially large logarithmic contributions to the integrated jet thrust distribution at L loops by making use of analogous contributions to the simpler integrated hemisphere soft function.
The effect of the Polyakov loop on the chiral phase transition
Directory of Open Access Journals (Sweden)
Szép Zs.
2011-04-01
Full Text Available The Polyakov loop is included in the S U(2L × S U(2R chiral quark-meson model by considering the propagation of the constituent quarks, coupled to the (σ, π meson multiplet, on the homogeneous background of a temporal gauge field, diagonal in color space. The model is solved at finite temperature and quark baryon chemical potential both in the chiral limit and for the physical value of the pion mass by using an expansion in the number of flavors Nf. Keeping the fermion propagator at its tree-level, a resummation on the pion propagator is constructed which resums infinitely many orders in 1/Nf, where O(1/Nf represents the order at which the fermions start to contribute in the pion propagator. The influence of the Polyakov loop on the tricritical or the critical point in the µq – T phase diagram is studied for various forms of the Polyakov loop potential.
LoopIng: a template-based tool for predicting the structure of protein loops.
Messih, Mario Abdel
2015-08-06
Predicting the structure of protein loops is very challenging, mainly because they are not necessarily subject to strong evolutionary pressure. This implies that, unlike the rest of the protein, standard homology modeling techniques are not very effective in modeling their structure. However, loops are often involved in protein function, hence inferring their structure is important for predicting protein structure as well as function.We describe a method, LoopIng, based on the Random Forest automated learning technique, which, given a target loop, selects a structural template for it from a database of loop candidates. Compared to the most recently available methods, LoopIng is able to achieve similar accuracy for short loops (4-10 residues) and significant enhancements for long loops (11-20 residues). The quality of the predictions is robust to errors that unavoidably affect the stem regions when these are modeled. The method returns a confidence score for the predicted template loops and has the advantage of being very fast (on average: 1 min/loop).www.biocomputing.it/loopinganna.tramontano@uniroma1.itSupplementary data are available at Bioinformatics online.
Zhang, Xiancheng; Noda, Shigeho; Himeno, Ryutaro; Liu, Hao
2017-06-01
We present a novel methodology and strategy to predict pressures and flow rates in the global cardiovascular network in different postures varying from supine to upright. A closed-loop, multiscale mathematical model of the entire cardiovascular system (CVS) is developed through an integration of one-dimensional (1D) modeling of the large systemic arteries and veins, and zero-dimensional (0D) lumped-parameter modeling of the heart, the cardiac-pulmonary circulation, the cardiac and venous valves, as well as the microcirculation. A versatile junction model is proposed and incorporated into the 1D model to cope with splitting and/or merging flows across a multibranched junction, which is validated to be capable of estimating both subcritical and supercritical flows while ensuring the mass conservation and total pressure continuity. To model gravitational effects on global hemodynamics during postural change, a robust venous valve model is further established for the 1D venous flows and distributed throughout the entire venous network with consideration of its anatomically realistic numbers and locations. The present integrated model is proven to enable reasonable prediction of pressure and flow rate waveforms associated with cardiopulmonary circulation, systemic circulation in arteries and veins, as well as microcirculation within normal physiological ranges, particularly in mean venous pressures, which well match the in vivo measurements. Applications of the cardiovascular model at different postures demonstrate that gravity exerts remarkable influence on arterial and venous pressures, venous returns and cardiac outputs whereas venous pressures below the heart level show a specific correlation between central venous and hydrostatic pressures in right atrium and veins.
Chantawong, Nopwaree; Charoenkwan, Kittipat
2017-10-01
The aim of the study was to compare pain, anxiety, and satisfaction between women, who listened to music, and those who did not during loop electrosurgical excision procedure (LEEP). Participants were randomly assigned into two groups. In group 1 (music), the participants listened to relaxing instrumental music through the stereo headset from the time of arrival at the preoperative waiting room until the procedure completed. For group 2 (control), the participants underwent LEEP without music listening. The women rated pain, anxiety, and satisfaction according to 10-cm visual analog scales. Pain was assessed at the time of speculum insertion (baseline pain) and immediately after the LEEP completed (procedural pain). Anxiety and satisfaction were examined just before starting the LEEP and 10 minutes after the procedure completed. One hundred fifty patients (74 in music group and 76 in control group) participated. Mean baseline pain scores after speculum insertion were comparable between the groups (3.7 in the music group vs. 3.5 in the control group, p = .55). Mean procedural pain scores were not different between the groups (4.7 in the music group vs. 5.2 in the control group, p = .32). The differences of the procedural pain scores from baseline were statistically comparable between the study groups (0.9 in the music group vs. 1.7 in the control group, p = .15). There were no significant differences in anxiety and satisfaction scores at any time points assessed between the groups. The effects of music listening on reducing pain and anxiety during LEEP could not be demonstrated in this study.
International Nuclear Information System (INIS)
Brzoska, A.M.; Lenz, F.; Thies, M.; Negele, J.W.
2005-01-01
A phenomenological analysis of the distribution of Wilson loops in SU(2) Yang-Mills theory is presented in which Wilson loop distributions are described as the result of a diffusion process on the group manifold. It is shown that, in the absence of forces, diffusion implies Casimir scaling and, conversely, exact Casimir scaling implies free diffusion. Screening processes occur if diffusion takes place in a potential. The crucial distinction between screening of fundamental and adjoint loops is formulated as a symmetry property related to the center symmetry of the underlying gauge theory. The results are expressed in terms of an effective Wilson loop action and compared with various limits of SU(2) Yang-Mills theory
The Impact of Magnetomechanical Effects on Ferrite B-H Loop Shapes
DEFF Research Database (Denmark)
Baguley, C. A.; Madawala, U. K.; Carsten, B.
2012-01-01
Under high dc bias conditions, experimental observations show B-H loops can exhibit a figure-eight shape, as energy is returned from the magnetic core back to the magnetic excitation supply during a portion of the excitation cycle. However, an explanation for this phenomenon is yet to be reported...
The graviton one-loop effective action in cosmological space-times with constant deceleration
Janssen, T.M.; Prokopec, T.
2010-01-01
We consider the quantum Friedmann equations which include one-loop vacuum fluctuations due to gravitons and scalar field matter in a FLRW background with constant ¼ H_ =H2. After several field redefinitions, to remove the mixing between the gravitational and matter degrees of freedom, we can
Effects of Load and Speed Variations in a Modified Closed Loop V/F ...
African Journals Online (AJOL)
This paper investigates the eects of load and reference speed variations in a modied closed loopv=f induction motor drive. A modied approach, involving the addition of a low frequency boostvoltage, is developed and adopted as an enhancement to the conventional closed loop v=f speedcontrol of a three phase squirrel ...
Two-loop disorder effects on the nematic quantum criticality in d-wave superconductors
International Nuclear Information System (INIS)
Wang, Jing
2015-01-01
The gapless nodal fermions exhibit non-Fermi liquid behaviors at the nematic quantum critical point that is supposed to exist in some d-wave cuprate superconductors. This non-Fermi liquid state may be turned into a disorder-dominated diffusive metal if the fermions also couple to a disordered potential that generates a relevant perturbation in the sense of renormalization group theory. It is therefore necessary to examine whether a specific disorder is relevant or not. We study the interplay between critical nematic fluctuation and random chemical potential by performing renormalization group analysis. The parameter that characterizes the strength of random chemical potential is marginal at the one-loop level, but becomes marginally relevant after including the two-loop corrections. Thus even weak random chemical potential leads to diffusive motion of nodal fermions and the significantly critical behaviors of physical implications, since the strength flows eventually to large values at low energies. - Highlights: • The gapless nodal fermions exhibit non-Fermi liquid behaviors at the nematic QCP. • The strength of random chemical potential is marginal at the one-loop level. • The strength becomes marginally relevant after including the two-loop corrections. • The diffusive metallic state is induced by the marginally relevant disorder. • The behaviors of some physical observables are presented at the nematic QCP
Spurgeon, Jessica; Ward, Geoff; Matthews, William J.
2014-01-01
We examined the contribution of the phonological loop to immediate free recall (IFR) and immediate serial recall (ISR) of lists of between one and 15 words. Following Baddeley (1986, 2000, 2007, 2012), we assumed that visual words could be recoded into the phonological store when presented silently but that recoding would be prevented by…
Directory of Open Access Journals (Sweden)
Damjanović Miodrag
2014-01-01
Full Text Available Introduction. Entrapment and fracture of diagnostic or therapeutic devices within the coronary circulatory system are a rare, but increasing problem. Case report. A 70-yearold man was admitted in our clinic for coronary angiography before the planned aortic valve replacement. An arterial sheath was inserted in the right common femoral artery. After introducing a J-tip diagnostic coronary guidewire into the aorta and advancing a left Judkins diagnostic catheter over it, suddenly occured peeling off of the wire´s hydrophilic coating at the aortic arch level. Very soon, this outer coating of guidewire carried by the blood stream was entered into the left femoral artery, then into the left popliteal artery. This stripped part of guidewire was successfully caught and extracted out by using a goose-neck snare catheter. Conclusion. A sudden stripping of outer coating of a J-tip diagnostic hydrophilic coronary guidewire during coronary angiography is possible to manage quickly and successfully by the use of a simple cathether.
International Nuclear Information System (INIS)
Jung, Eui Guk; Boo, Joon Hong
2008-01-01
This study deals with a mathematical modeling for the steady-state temperature characteristics of an entire loop heat pipe. The lumped layer model was applied to each node for temperature analysis. The flat type evaporator and condenser in the model had planar dimensions of 40 mm (W) x 50 mm (L). The wick material was a sintered metal and the working fluid was methanol. The molecular kinetic theory was employed to model the phase change phenomena in the evaporator and the condenser. Liquid-vapor interface configuration was expressed by the thin film theories available in the literature. Effects of design factors of loop heat pipe on the thermal performance were investigated by the modeling proposed in this study
The analysis of SCS return momentum effects on the RCS water level during mid-loop operations
Energy Technology Data Exchange (ETDEWEB)
swang Seo, J.; Young Yang, J.; Tack Hwang, S. [Seoul National Univ. (Korea, Republic of)
1995-09-01
An accurate prediction of Reactor Coolant System (RCS) water levels is of importance in the determination of allowable operating range to ensure the safety during the mid-loop operations. However, complex hydraulic phenomena induced by Shutdown Cooling System (SCS) return momentum cause different water levels from those in the loop where the water level indicators are located. This was apparantly observed at the pre-core cold hydro test of the Younggwang Nuclear Unit 3 (YGN 3) in Korea. In this study, in order to analytically understand the effect of the SCS return momentum on the RCS water level and its general trend, a model using one-dimensional momentum equation, hydraulic jump, Bernoulli equation, flow resistance coefficient, and total water volume conservation has been developed to predict the RCS water levels at various RCS locations during the mid-loop conditions and the simulation results were compared with the test data. The analysis shows that the hydraulic jump in the operating cold legs in conjunction with the momentum loss throughout the RCS is the main cause creating the water level differences at various RCS locations. The prediction results provide good explanations for the test data and show the significant effect of the SCS return momentum on the RCS water levels.
Directory of Open Access Journals (Sweden)
S. Hayakawa
2016-12-01
Full Text Available Molecular dynamics simulations were conducted to investigate the effects of stacking fault energy (SFE as a single variable parameter on the interaction between an edge dislocation and a Frank loop of self-interstitial atoms with a diameter of 8.0nm. The physical contact between the edge dislocation and the loop causes constriction of the edge dislocation, followed by the formation of a D-Shockley partial dislocation. The latter process is associated with either the formation of a screw component and its cross-slip, or the direct core reaction between the dislocation and the loop. These processes induce either the absorption of the loop into the dislocation or the transformation of the loop into a perfect loop. The SFE influences the interaction morphologies by determining the separation distance of the two partial dislocations and consequently the rate of constriction. The dependence of the interaction morphology on the SFE varies with the habit plane of the loop. A higher SFE increases the probability of the absorption or transformation interaction; however, only loop shearing is observed at the lower limit of the SFE range of austenitic stainless steels.
Hashimoto, Sho; Takahashi, Akihiko; Yamada, Takeshi; Mizuguchi, Yukio; Taniguchi, Norimasa; Hata, Tetsuya; Nakajima, Shunsuke
2017-11-20
The extension support guiding catheter has been used to perform complex percutaneous coronary intervention to increase back-up support for the guiding catheter or to ensure deep intubation for device delivery. However, because of its monorail design, advancement of the stent into the distal extension tubing segment is sometimes problematic. Although this problem is considered due to simple collision of the stent, operators have observed tangling between a monorail extension catheter and coronary guidewire in some patients. To examine movement of the collar of the extension guide catheter during advancement of the guiding catheter, we set up an in vitro model in which the guiding catheter had two curves. Rotation of the extension guide catheter was examined by both fluoroscopic imaging and movement of the hub of the proximal end of the catheter. During advancement in the first curve, the collar moved toward the outer side of the curve of the guiding catheter as the operator pushed the shaft of the extension guiding catheter, which overrode the guidewire. After crossing the first curve, the collar moved again to the outer side of the second curve (the inner side of the first curve) of the mother catheter, and then, another clockwise rotation was observed in the proximal hub. Consequently, the collar and tubing portion of the extension guide catheter rotated 360° around the coronary guidewire, and the monorail extension catheter and guidewire became tangled. There is a potential risk of unintentional twisting with the guidewire during advancement into the curved guiding catheter because of its monorail design.
Effect of the Gribov horizon on the Polyakov loop and vice versa
Energy Technology Data Exchange (ETDEWEB)
Canfora, F.E. [Centro de Estudios Cientificos (CECS), Valdivia (Chile); Dudal, D. [KU Leuven Campus Kortrijk, KULAK, Department of Physics, Kortrijk (Belgium); Ghent University, Department of Physics and Astronomy, Gent (Belgium); Justo, I.F. [Ghent University, Department of Physics and Astronomy, Gent (Belgium); UERJ, Universidade do Estado do Rio de Janeiro, Departamento de Fisica Teorica, Instituto de Fisica, Maracana, Rio de Janeiro (Brazil); Pais, P. [Centro de Estudios Cientificos (CECS), Valdivia (Chile); Universite Libre de Bruxelles and International Solvay Institutes, Physique Theorique et Mathematique, Brussels (Belgium); Rosa, L. [Universita di Napoli Federico II, Dipartimento di Fisica, Monte S. Angelo (Italy); INFN, Sezione di Napoli, Monte S. Angelo (Italy); Vercauteren, D. [Duy Tan University, Institute of Research and Development, Da Nang (Viet Nam)
2015-07-15
We consider finite-temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of the Gribov-Zwanziger quantization scheme, which entails the introduction of a dynamical mass scale (Gribov mass) directly influencing the Green functions of the theory. Here, we determine simultaneously the Polyakov loop (vacuum expectation value) and Gribov mass in terms of temperature, by minimizing the vacuum energy w.r.t. the Polyakov-loop parameter and solving the Gribov gap equation. Inspired by the Casimir energy-style of computation, we illustrate the usage of Zeta function regularization in finite-temperature calculations. Our main result is that the Gribov mass directly feels the deconfinement transition, visible from a cusp occurring at the same temperature where the Polyakov loop becomes nonzero. In this exploratory work we mainly restrict ourselves to the original Gribov-Zwanziger quantization procedure in order to illustrate the approach and the potential direct link between the vacuum structure of the theory (dynamical mass scales) and (de)confinement. We also present a first look at the critical temperature obtained from the refined Gribov-Zwanziger approach. Finally, a particular problem for the pressure at low temperatures is reported. (orig.)
Effects of performance level on lower limb kinematics during table tennis forehand loop.
Qian, Jieyuan; Zhang, Yan; Baker, Julien S; Gu, Yaodong
2016-01-01
Understanding of biomechanics is important in performance development since each skill has a fundamental mechanical structure. The purpose of this study was to investigate differences in lower limb kinematics during table tennis forehand loop between superior players (SP) and intermediate players (IP). Thirteen male players as superior and thirteen as intermediate participated in this test. A VICON motion analysis system and a Novel Pedar insole plantar pressure measurement system were used to record kinematic and contact area data, respectively. Participants were asked to execute single forehand loop against topspin ball with maximal power. Key findings were that SP showed significantly larger hip flexion and knee external rotation at backward-end and larger hip internal rotation and extension at forward-end compared with IP. Contact areas at both events were larger for SP. In addition, SP showed significantly larger joints angular changing rate during forward swing at the ankle and hip. Results indicated that SP possessed better ability of using lower limb drive in forehand loop.
Tertinek, Stefan; Feely, Orla
2009-01-01
Recently, several digital phase-locked loops (DPLLs) have been demonstrated to achieve the jitter performance of traditional charge-pump-based analog PLLs. This paper is concerned with a class of DPLLs employing a binary-quantized phase detector, referred to as bangbang PLLs (BBPLLs). They are widely used in clock and data recovery circuits and have recently been implemented as digital BBPLLs for high-bandwidth synthesis. Given that a DPLL implementation typically suffers from (excess) ...
N'Diaye, M.; Martinache, F.; Jovanovic, N.; Lozi, J.; Guyon, O.; Norris, B.; Ceau, A.; Mary, D.
2018-02-01
Context. Island effect (IE) aberrations are induced by differential pistons, tips, and tilts between neighboring pupil segments on ground-based telescopes, which severely limit the observations of circumstellar environments on the recently deployed exoplanet imagers (e.g., VLT/SPHERE, Gemini/GPI, Subaru/SCExAO) during the best observing conditions. Caused by air temperature gradients at the level of the telescope spiders, these aberrations were recently diagnosed with success on VLT/SPHERE, but so far no complete calibration has been performed to overcome this issue. Aims: We propose closed-loop focal plane wavefront control based on the asymmetric Fourier pupil wavefront sensor (APF-WFS) to calibrate these aberrations and improve the image quality of exoplanet high-contrast instruments in the presence of the IE. Methods: Assuming the archetypal four-quadrant aperture geometry in 8 m class telescopes, we describe these aberrations as a sum of the independent modes of piston, tip, and tilt that are distributed in each quadrant of the telescope pupil. We calibrate these modes with the APF-WFS before introducing our wavefront control for closed-loop operation. We perform numerical simulations and then experimental tests on a real system using Subaru/SCExAO to validate our control loop in the laboratory and on-sky. Results: Closed-loop operation with the APF-WFS enables the compensation for the IE in simulations and in the laboratory for the small aberration regime. Based on a calibration in the near infrared, we observe an improvement of the image quality in the visible range on the SCExAO/VAMPIRES module with a relative increase in the image Strehl ratio of 37%. Conclusions: Our first IE calibration paves the way for maximizing the science operations of the current exoplanet imagers. Such an approach and its results prove also very promising in light of the Extremely Large Telescopes (ELTs) and the presence of similar artifacts with their complex aperture geometry.
Fujita, Takanari; Saito, Naritatsu; Minakata, Kenji; Imai, Masao; Yamazaki, Kazuhiro; Kimura, Takeshi
2017-07-01
An 82-year-old woman with severe aortic stenosis was referred. She had previously undergone mitral valve replacement. We planned transcatheter aortic valve implantation (TAVI) with transfemoral approach. We planned to use the Safari-dedicated TAVI guidewire. No studies have reported clinical application of the dedicated TAVI guidewire in a patient with the previous mitral valve replacement. Thus, we conducted a simulation using a three-dimensional heart model to confirm the safety of the procedure. The procedure was successful without any complications. This case is the first to show that the dedicated TAVI guidewire can be safely used in patients with preexisting mitral valve.
George, Sudhakar; Cotton, James; Wrigley, Ben
2015-12-01
A 62-year-old man presented with an anterior ST elevation myocardial infarction and underwent primary percutaneous coronary intervention to an occluded diagonal artery. Following stenting, a type III distal guidewire-induced coronary perforation of the diagonal branch was recognized with extravasation of contrast into the pericardial space. Prolonged balloon inflations proximal to the site of the perforation were unsuccessful. Subcutaneous fat was therefore harvested from the patients upper thigh under local anesthetic and embolized through an Export catheter into the distal diagonal vessel, resulting in the immediate cessation of leak through the site of perforation. We discuss the technical aspects of this technique as well as alternative methods of distal embolization and the potential complications that must be considered. © 2015 Wiley Periodicals, Inc.
Emohare, Osa; Peterson, Erik; Slinkard, Nathaniel; Janus, Seth; Morgan, Robert
2013-10-01
Study Design Case report. Clinical Question The clinical aim is to report on a previously unknown association between guidewire-assisted pedicle screw insertion and neuropraxia of the recurrent laryngeal nerve (RLN), and how this may overlap with the signs of Tapia syndrome; we also report our approach to the clinical management of this patient. Methods A 17-year-old male patient with idiopathic scoliosis experienced Tapia syndrome after posterior instrumentation and arthrodesis at the level of T1-L1. After extubation, the patient had a hoarse voice and difficulty in swallowing. Imaging showed a breach in the cortex of the anterior body of T1 corresponding to the RLN on the right. Results Otolaryngological examination noted right vocal fold immobility, decreased sensation of the endolarynx, and pooling of secretions on flexible laryngoscopy that indicated right-sided cranial nerve X injury and left-sided tongue deviation. Aspiration during a modified barium swallow prompted insertion of a percutaneous endoscopic gastrostomy tube before the patient was sent home. On postoperative day 20, a barium swallow demonstrated reduced aspiration, and the patient reported complete resolution of symptoms. The feeding tube was removed, and the patient resumed a normal diet 1 month later. Tapia syndrome, or persistent unilateral laryngeal and hypoglossal paralysis, is an uncommon neuropraxia, which has previously not been observed in association with a breached vertebral body at T1 along the course of the RLN. Conclusion Tapia syndrome should be a differential diagnostic consideration whenever these symptoms persist postoperatively and spine surgeons should be aware of this as a potential complication of guidewires in spinal instrumentation.
Satyanarayana, B.; Majumder, G.; Mondal, N. K.; Kalmani, S. D.; Shinde, R. R.; Joshi, A.
2014-10-01
Pilot unit of a closed loop gas mixing and distribution system for the INO project was designed and is being operated with 1.8meters × 1.9meters RPCs for about two years. A number of studies on controlling the flow and optimisation of the gas mixture through the RPC stack were carried out during this period. The gas system essentially measures and attempts to maintain absolute pressure inside the RPC gas volume. During typical Mumbai monsoon seasons, the barometric pressure changes rather rapidly, due to which the gas system fails to maintain the set differential pressure between the ambience and the RPC gas volume. As the safety bubblers on the RPC gas input lines are set to work on fixed pressure differentials, the ambient pressure changes lead to either venting out and thus wasting gas through safety bubblers or over pressuring the RPCs gas volume and thus degrading its performance. The above problem also leads to gas mixture contamination through minute leaks in gas gap. The problem stated above was solved by including the ambient barometric pressure as an input parameter in the closed loop. Using this, it is now possible to maintain any set differential pressure between the ambience and RPC gas volumes between 0 to 20mm of water column, thus always ensuring a positive pressure inside the RPC gas volume with respect to the ambience. This has resulted in improved performance of the gas system by maintaining the constant gas flow and reducing the gas toping up frequency. In this paper, we will highlight the design features and improvements of the closed loop gas system. We will present some of the performance studies and considerations for scaling up the system to be used with the engineering module and then followed by Iron Calorimeter detector (ICAL), which is designed to deploy about 30,000 RPCs of 1.8meters × 1.9 meters in area.
Wind turbine inverter robust loop-shaping control subject to grid interaction effects
DEFF Research Database (Denmark)
Gryning, Mikkel Peter Sidoroff; Wu, Qiuwei; Blanke, Mogens
2015-01-01
the grid and the number of wind turbines connected. Power converter based turbines inject harmonic currents, which are attenuated by passive filters. A robust high order active filter controller is proposed to complement the passive filtering. The H∞ design of the control loop enables desired tracking......An H∞ robust control of wind turbine inverters employing an LCL filter is proposed in this paper. The controller dynamics are designed for selective harmonic filtering in an offshore transmission network subject to parameter perturbations. Parameter uncertainty in the network originates from...
Effectiveness of flossing loops in the control of the gingival health
Azcarate-Vel?zquez, Francisco; Garrido-Serrano, Roberto; Castillo-Dal?, Gabriel; Serrera-Figallo, Mar?a-Angeles; Ga??n-Calvo, Alfonso; Torres-Lagares, Daniel
2017-01-01
Background One of the key factor in the good condition of periodontal tissues is their daily hygiene. Oral hygiene techniques such brushing and a good interdental hygiene by correct flossing are very important. The aim of this study is to compare the use of dental floss in a loop vs traditional floss in the control of Loe-Silness Gingival Index (IG), Turesky?s Plaque Index (IPT), Gingival Bleeding Index (IS) and the values of interleukin 6 (IL-6) and interleukin 8 (IL-8). Material and Methods...
Bergstrand, C R
1979-10-01
Ryan's (1971) description of the ideology of "victim-blaming" is briefly reviewed. It is then shown how this strategy for obscuring the causes of a social problem is used against rural, medically underserved communities by health care provider and planning interest groups to "explain" critical shortages of physicians in their areas. In addition to lending further support for the existence of this ideology, a "looping" effect of social policy designed to deal with physician maldistribution is identified. It is argued that this can be viewed as analytically distinct from the ideology itself and that it serves the purpose of further obscuring the larger structural sources of the social problem.
DEFF Research Database (Denmark)
Niero, Monia; Hauschild, Michael Zwicky; Hoffmeyer, Simon Boas
2017-01-01
Eco-efficiency (i.e., increasing value while reducing resource use and pollution) can with advantage be combined with eco-effectiveness (i.e., maximizing the benefits to ecological and economical systems) to address the challenges posed by the circular economy in the design of circular industrial...... systems. We present a framework combining life cycle assessment (LCA) and the Cradle to CradleÂ® (C2C) certification program for the development of continuous loop packaging systems, which was conceived for aluminum cans in the context of the Carlsberg Circular Community. As a first step...
International Nuclear Information System (INIS)
Okawa, Yuji
1999-01-01
The one-loop effective action for general trajectories of D-particles in Matrix theory is calculated in the expansion with respect to the number of derivatives up to six, which gives the equation of motion consistently. The result shows that the terms with six derivatives vanish for straight-line trajectories, however, they do not vanish in general. This provides a concrete example that non-renormalization of twelve-fermion terms does not necessarily imply that of six-derivative terms
Nair, Pradeep K; Carr, Jeffrey G; Bigelow, Brian; Bhatt, Deepak L; Berwick, Zachary C; Adams, George
2018-01-01
Proper vessel sizing during endovascular interventions is crucial to avoid adverse procedural and clinical outcomes. LumenRECON (LR) is a novel, nonimaging, 0.035-inch wire-based technology that uses the physics-based principle of Ohm's law to provide a simple, real-time luminal size while also providing a platform for therapy delivery. This study evaluated the accuracy, reliability, and safety of the LR system in patients presenting for a femoropopliteal artery intervention. This multicenter, prospective pilot study of 24 patients presenting for peripheral intervention compared LR measurements of femoropopliteal artery size to angiographic visual estimation, duplex ultrasound, quantitative angiography, and intravascular ultrasound. The primary effectiveness and safety end point was comparison against core laboratory adjudicated intravascular ultrasound values and major adverse events, respectively. Additional preclinical studies were also performed in vitro and in vivo in swine to determine the accuracy of the LR guidewire system. No intra- or postprocedure device-related adverse events occurred. A balloon or stent was successfully delivered in 12 patients (50%) over the LR wire. Differences in repeatability between successive LR measurements was 2.5±0.40% ( R 2 =0.96) with no significant bias. Differences in measurements of LR to other modalities were 0.5±1.7%, 5.0±1.8%, -1.5±2.0%, and 6.8±3.4% for intravascular ultrasound core laboratory, quantitative angiography, angiographic, and duplex ultrasound, respectively. This study demonstrates that through a physics-based principle, LR provides a real-time, safe, reproducible, and accurate vessel size of the femoropopliteal artery during intervention and can additionally serve as a conduit for therapy delivery over its wire-based platform. © 2018 American Heart Association, Inc.
Barone, Vanessa; Lang, Moritz; Krens, S F Gabriel; Pradhan, Saurabh J; Shamipour, Shayan; Sako, Keisuke; Sikora, Mateusz; Guet, Călin C; Heisenberg, Carl-Philipp
2017-10-23
Cell-cell contact formation constitutes an essential step in evolution, leading to the differentiation of specialized cell types. However, remarkably little is known about whether and how the interplay between contact formation and fate specification affects development. Here, we identify a positive feedback loop between cell-cell contact duration, morphogen signaling, and mesendoderm cell-fate specification during zebrafish gastrulation. We show that long-lasting cell-cell contacts enhance the competence of prechordal plate (ppl) progenitor cells to respond to Nodal signaling, required for ppl cell-fate specification. We further show that Nodal signaling promotes ppl cell-cell contact duration, generating a positive feedback loop between ppl cell-cell contact duration and cell-fate specification. Finally, by combining mathematical modeling and experimentation, we show that this feedback determines whether anterior axial mesendoderm cells become ppl or, instead, turn into endoderm. Thus, the interdependent activities of cell-cell signaling and contact formation control fate diversification within the developing embryo. Copyright © 2017 Elsevier Inc. All rights reserved.
The occluding loop of cathepsin B prevents its effective inhibition by human kininogens.
Naudin, C; Lecaille, F; Chowdhury, S; Krupa, J C; Purisima, E; Mort, J S; Lalmanach, G
2010-07-30
Kininogens, the major plasma cystatin-like inhibitors of cysteine cathepsins, are degraded at sites of inflammation, and cathepsin B has been identified as a prominent mediator of this process. Cathepsin B, in contrast to cathepsins L and S, is poorly inhibited by kininogens. This led us to delineate the molecular interactions between this protease and kininogens (high molecular weight kininogen and low molecular weight kininogen) and to elucidate the dual role of the occluding loop in this weak inhibition. Cathepsin B cleaves high molecular weight kininogen within the N-terminal region of the D2 and D3 cystatin-like domains and close to the consensus QVVAG inhibitory pentapeptide of the D3 domain. The His110Ala mutant, unlike His111Ala cathepsin B, fails to hydrolyze kininogens, but rather forms a tight-binding complex as observed by gel-filtration analysis. K(i) values (picomolar range) as well as association rate constants for the His110Ala cathepsin B variant compare to those reported for cathepsin L for both kininogens. Homology modeling of isolated inhibitory (D2 and D3) domains and molecular dynamics simulations of the D2 domain complexed with wild-type cathepsin B and its mutants indicate that additional weak interactions, due to the lack of the salt bridge (Asp22-His110) and the subsequent open position of the occluding loop, increase the inhibitory potential of kininogens on His110Ala cathepsin B. Copyright 2010 Elsevier Ltd. All rights reserved.
Gaikwad, Avinash J.; Vijayan, P. K.; Iyer, Kannan; Bhartiya, Sharad; Kumar, Rajesh; Lele, H. G.; Ghosh, A. K.; Kushwaha, H. S.; Sinha, R. K.
2009-12-01
For AHWR (Advanced Heavy Water Reactor), a pressure tube type Boiling Water Reactor (BWR) with parallel inter-connected loops, the Steam Drum (SD) level control is closely related to Main Heat Transport (MHT) coolant inventory and sustained heat removal through natural circulation, hence overall safety of the power plant. The MHT configuration with multiple (four) interconnected loops influences the SD level control in a manner which has not been previously addressed. The MHT configuration has been chosen based on comprehensive overall design requirements and certain Postulated Initiated Event (PIEs) for Loss of Coolant Accident (LOCA), which postulates a double ended break in the four partitioned Emergency Core Cooling System (ECCS) header. A conventional individual three-element SD level controller can not account for the highly coupled and interacting behaviors, of the four SD levels. An innovative three-element SD level control scheme is proposed to overcome this situation. The response obtained for a variety of unsymmetrical disturbances shows that the SD levels do not diverge and quickly settle to the various new set points assigned. The proposed scheme also leads to enhanced safety margins for most of the PIEs considered with a little influence on the 100% full power steady-state design conditions.
High-temperature expansion of the one-loop effective action induced by scalar and Dirac particles
Kalinichenko, Igor; Kazinski, Peter
2017-12-01
The complete nonperturbative expressions for the high-temperature expansion of the one-loop effective action induced by the charged scalar and the charged Dirac particles both at zero and finite temperatures are derived with account of possible nontrivial boundary conditions. The background electromagnetic field is assumed to be stationary and such that the corresponding Klein-Gordon operator or the Dirac Hamiltonian is self-adjoint. The contributions of particles and antiparticles are obtained separately. The explicit expressions for the C-symmetric and the non- C-symmetric vacuum energies of the Dirac fermions are derived. The leading corrections to the high-temperature expansion due to the nontrivial boundary conditions are explicitly found. The corrections to the logarithmic divergence of the effective action that come from the boundary conditions are derived. The high-temperature expansion of the naive one-loop effective action induced by charged fermions turns out to be divergent in the limit of a zero fermion mass.
High-temperature expansion of the one-loop effective action induced by scalar and Dirac particles
Energy Technology Data Exchange (ETDEWEB)
Kalinichenko, Igor; Kazinski, Peter [Tomsk State University, Physics Faculty, Tomsk (Russian Federation)
2017-12-15
The complete nonperturbative expressions for the high-temperature expansion of the one-loop effective action induced by the charged scalar and the charged Dirac particles both at zero and finite temperatures are derived with account of possible nontrivial boundary conditions. The background electromagnetic field is assumed to be stationary and such that the corresponding Klein-Gordon operator or the Dirac Hamiltonian is self-adjoint. The contributions of particles and antiparticles are obtained separately. The explicit expressions for the C-symmetric and the non-C-symmetric vacuum energies of the Dirac fermions are derived. The leading corrections to the high-temperature expansion due to the nontrivial boundary conditions are explicitly found. The corrections to the logarithmic divergence of the effective action that come from the boundary conditions are derived. The high-temperature expansion of the naive one-loop effective action induced by charged fermions turns out to be divergent in the limit of a zero fermion mass. (orig.)
Loop quantum cosmology: Recent progress
Indian Academy of Sciences (India)
Aspects of the full theory of loop quantum gravity can be studied in a simpler context by reducing to symmetric models like cosmological ones. This leads to several applications where loop effects play a significant role when one is sensitive to the quantum regime. As a consequence, the structure of and the approach to ...
Higher dimensional loop quantum cosmology
International Nuclear Information System (INIS)
Zhang, Xiangdong
2016-01-01
Loop quantum cosmology (LQC) is the symmetric sector of loop quantum gravity. In this paper, we generalize the structure of loop quantum cosmology to the theories with arbitrary spacetime dimensions. The isotropic and homogeneous cosmological model in n + 1 dimensions is quantized by the loop quantization method. Interestingly, we find that the underlying quantum theories are divided into two qualitatively different sectors according to spacetime dimensions. The effective Hamiltonian and modified dynamical equations of n + 1 dimensional LQC are obtained. Moreover, our results indicate that the classical big bang singularity is resolved in arbitrary spacetime dimensions by a quantum bounce. We also briefly discuss the similarities and differences between the n + 1 dimensional model and the 3 + 1 dimensional one. Our model serves as a first example of higher dimensional loop quantum cosmology and offers the possibility to investigate quantum gravity effects in higher dimensional cosmology. (orig.)
Study of open-charm 0^+ states in unitarized chiral effective theory with one-loop potentials
Du, Meng-Lin; Guo, Feng-Kun; Meißner, Ulf-G.; Yao, De-Liang
2017-11-01
Chiral potentials are derived for the interactions between Goldstone bosons and pseudo-scalar charmed mesons up to next-to-next-to-leading order in a covariant chiral effective field theory with explicit vector charmed-meson degrees of freedom. Using the extended-on-mass-shell scheme, we demonstrate that the ultraviolet divergences and the so-called power counting breaking terms can be properly absorbed by the low-energy constants of the chiral Lagrangians. We calculate the scattering lengths by unitarizing the one-loop potentials and fit them to the data extracted from lattice QCD. The obtained results are compared to the ones without an explicit contribution of vector charmed mesons given previously. It is found that the difference is negligible for S-wave scattering in the threshold region. This validates the use of D^*-less one-loop potentials in the study of the pertinent scattering lengths. We search for dynamically generated open-charm states with J^P=0^+ as poles of the S-matrix on various Riemann sheets. The trajectories of those poles for varying pion masses are presented as well.
Study of open-charm 0{sup +} states in unitarized chiral effective theory with one-loop potentials
Energy Technology Data Exchange (ETDEWEB)
Du, Meng-Lin [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Guo, Feng-Kun [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Meissner, Ulf G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik and Juelich Center for Hadron Physics (Germany); Yao, De-Liang [Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik and Juelich Center for Hadron Physics (Germany); Instituto de Fisica Corpuscular (Centro mixto CSIC-UV), Institutos de Investigacion de Paterna, Valencia (Spain)
2017-11-15
Chiral potentials are derived for the interactions between Goldstone bosons and pseudo-scalar charmed mesons up to next-to-next-to-leading order in a covariant chiral effective field theory with explicit vector charmed-meson degrees of freedom. Using the extended-on-mass-shell scheme, we demonstrate that the ultraviolet divergences and the so-called power counting breaking terms can be properly absorbed by the low-energy constants of the chiral Lagrangians. We calculate the scattering lengths by unitarizing the one-loop potentials and fit them to the data extracted from lattice QCD. The obtained results are compared to the ones without an explicit contribution of vector charmed mesons given previously. It is found that the difference is negligible for S-wave scattering in the threshold region. This validates the use of D*-less one-loop potentials in the study of the pertinent scattering lengths. We search for dynamically generated open-charm states with J{sup P} = 0{sup +} as poles of the S-matrix on various Riemann sheets. The trajectories of those poles for varying pion masses are presented as well. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Zhang, Weiping [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Luo, Fengfeng [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China); Yu, Yanxia; Zheng, Zhongcheng; Shen, Zhenyu [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Ren, Yaoyao [Center for Electron Microscopy, Wuhan University, Wuhan 430072 (China); Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)
2016-10-15
Single-beam and sequential-beam irradiations were performed to investigate the H/He synergistic effect on dislocation loops in reduced-activation ferritic/martensitic (RAFM) steels. The irradiations were carried out with 10 keV H{sup +}, 18 keV He{sup +} and 160 keV Ar{sup +}, alone and in combination at 723 K. He{sup +} single-beam irradiation induced much larger dislocation loops than that induced by both H{sup +} and Ar{sup +} single-beam irradiation. H{sup +} post-irradiation after He{sup +} irradiation further increased the size of dislocation loops, whilst He{sup +} post-irradiation or Ar{sup +} post-irradiation following H{sup +} irradiation only slightly increased the size of dislocation loops. The experiment results indicate that pre-implanted H{sup +} can drastically inhibit the growth while post-implanted H{sup +} can significantly enhance the growth of dislocation loops induced by He{sup +} irradiation. The mechanisms behind the complex synergistic phenomena between H and He and the different roles that H and He played in the growth of dislocation loops are discussed.
Energy Technology Data Exchange (ETDEWEB)
Chatterjee, Arka [Division of Cardiology, University of Alabama-Birmingham (United States); Brott, Brigitta C. [Division of Cardiology, University of Alabama-Birmingham (United States); Department of Biomedical Engineering, University of Alabama-Birmingham (United States); Foley, Robin [Department of Material Science and Engineering, University of Alabama-Birmingham (United States); Alli, Oluseun; Sasse, Mark; Ahmed, Mustafa; Al Solaiman, Firas; Reddy, Gautam; Ather, Sameer [Division of Cardiology, University of Alabama-Birmingham (United States); Leesar, Massoud A., E-mail: mleesar@uab.edu [Division of Cardiology, University of Alabama-Birmingham (United States)
2016-10-15
Background and propose: In coronary bifurcation lesions (CBL), hydrophilic guidewires used for side-branch (SB) protection can be withdrawn from underneath the stent easier than other wires. However, the safety of which has not been investigated. Methods/materials: We performed scanning electron microscopic (SEM) examination of hydrophilic wires – the Whisper and Runthrough wires – used for SB protection during stenting and proximal optimization technique (POT) in 30 patients with CBL. The distal 15 cm of the wire was examined every 1 mm by SEM and 4500 segments were analyzed to investigate for wire fracture, polymer shearing (PS), and its correlations with post-stenting creatine kinase (CK)-MB release. Results: SEM examination showed no evidence for wire fracture. The total area of PS and the largest defect on the wire were significantly larger with the Whisper wire versus the Runthrough wire (0.15 ± 0.04 mm{sup 2} vs. 0.026 ± 0.01 mm{sup 2} and 0.04 ± 0.05 mm{sup 2} vs. 0.01 ± 0.01 mm{sup 2}; P < 0.05, respectively). The total length of PS and the longest defect on the wire were significantly longer with the Whisper wire vs. the Runthrough wire (12.1 ± 14.5 mm vs. 2.7 ± 3.0 mm and 2.9 ± 4.2 mm vs. 1.0 ± 1.2 mm; P < 0.05, respectively), but there were weak correlations between the extents of PS with CK-MB release. Conclusions: Hydrophilic guidewires may be safely used for SB protection during stenting and POT in CBLs. The extent of PS was significantly greater with the Whisper wire than with the Runthrough wire, but its correlation with post-stenting CK-MB release was weak. - Highlights: • There was no wire fracture by jailing hydrophilic wires. • There was no wire entrapment by jailing hydrophilic wires. • There were weak correlations between polymer shearing and creatine kinase-MB levels. • The impact of polymer shearing on myocardial infraction warrants future studies.
Katona, Thomas R; Isikbay, Serkis C; Chen, Jie
2014-03-01
To measure the effects of first- and second-order gable bends on the forces and moments produced by a commercially available closing T-loop archwire. A dentoform-simulated space closure case was mounted on an orthodontic force tester. Sixteen gable bend combinations were placed in the archwires, which were then activated using standard clinical procedures. At each activation, the three force components and three moment components on the maxillary left lateral incisor and canine were simultaneously measured. The first- and second-order gable bends showed low load coupling effects when used independently, but the load systems became unpredictable when bends were combined. Gable bends affect the magnitudes and directions of the forces and moments that are applied to teeth. The resulting moment to force ratios are sensitive to the bends. Gable bends alter the orthodontic load systems; however, the three-dimensional interactions produce complex and unpredictable tradeoffs.
Effects of FGFR2 kinase activation loop dynamics on catalytic activity.
Directory of Open Access Journals (Sweden)
Jerome M Karp
2017-02-01
Full Text Available The structural mechanisms by which receptor tyrosine kinases (RTKs regulate catalytic activity are diverse and often based on subtle changes in conformational dynamics. The regulatory mechanism of one such RTK, fibroblast growth factor receptor 2 (FGFR2 kinase, is still unknown, as the numerous crystal structures of the unphosphorylated and phosphorylated forms of the kinase domains show no apparent structural change that could explain how phosphorylation could enable catalytic activity. In this study, we use several enhanced sampling molecular dynamics (MD methods to elucidate the structural changes to the kinase's activation loop that occur upon phosphorylation. We show that phosphorylation favors inward motion of Arg664, while simultaneously favoring outward motion of Leu665 and Pro666. The latter structural change enables the substrate to bind leading to its resultant phosphorylation. Inward motion of Arg664 allows it to interact with the γ-phosphate of ATP as well as the substrate tyrosine. We show that this stabilizes the tyrosine and primes it for the catalytic phosphotransfer, and it may lower the activation barrier of the phosphotransfer reaction. Our work demonstrates the value of including dynamic information gleaned from computer simulation in deciphering RTK regulatory function.
Managing a closed-loop supply chain inventory system with learning effects
Jauhari, Wakhid Ahmad; Dwicahyani, Anindya Rachma; Hendaryani, Oktiviandri; Kurdhi, Nughthoh Arfawi
2018-02-01
In this paper, we propose a closed-loop supply chain model consisting of a retailer and a manufacturer. We intend to investigate the impact of learning in regular production, remanufacturing and reworking. The customer demand is assumed deterministic and will be satisfied from both regular production and remanufacturing process. The return rate of used items depends on quality. We propose a mathematical model with the objective is to maximize the joint total profit by simultaneously determining the length of ordering cycle for the retailer and the number of regular production and remanufacturing cycle. The algorithm is suggested for finding the optimal solution. A numerical example is presented to illustrate the application of using a proposed model. The results show that the integrated model performs better in reducing total cost compared to the independent model. The total cost is most affected by the changes in the values of unit production cost and acceptable quality level. In addition, the changes in the defective items proportion and the fraction of holding costs significantly influence the retailer's ordering period.
Energy Technology Data Exchange (ETDEWEB)
Takata, Miki [Graduate School of Engineering, Soka University, Hachioji, Tokyo 192-8577 (Japan); Fukushima, Kazuyo [Watanabe Oyster Laboratory Co., Ltd, Hachioji, Tokyo 192-0154 (Japan); Kino-Kimata, Noriko [Graduate School of Engineering, Soka University, Hachioji, Tokyo 192-8577 (Japan); Nagao, Norio [Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Niwa, Chiaki [Graduate School of Engineering, Soka University, Hachioji, Tokyo 192-8577 (Japan); Toda, Tatsuki, E-mail: toda@soka.ac.jp [Graduate School of Engineering, Soka University, Hachioji, Tokyo 192-8577 (Japan)
2012-08-15
In Japan, a revised Food Recycling Law went into effect in 2007 to promote a 'recycling loop' that requires food industries to purchase farm products that are grown using food waste-derived compost/animal feed. To realize and expand food recycling, it is necessary to evaluate how the recycling facilities work in the recycling loop. The purpose of this study is to assess the environmental and economic efficiency of the food recycling facilities that are involved in the recycling loop, which are also known as looped facilities. The global warming potential and running cost of five looped facilities were evaluated by LCA (life cycle assessment) and LCC (life cycle cost) approaches: machine integrated compost, windrow compost, liquid feed, dry feed, and bio-gasification. The LCA results showed low total GHG (greenhouse gas) emissions of - 126 and - 49 kg-CO{sub 2}/t-waste, respectively, for dry feed and bio-gasification facilities, due to a high substitution effect. The LCC study showed a low running cost for composting facilities of - 15,648 and - 18,955 yen/t-waste, respectively, due to high revenue from the food waste collection. It was found that the mandatory reporting of food waste emitters to the government increased collection fees; however, the collection fee in animal feed facilities was relatively low because food waste was collected at a low price or nutritious food waste was purchased to produce quality feed. In the characterisation survey of various treatment methods, the composting facilities showed a relatively low environmental impact and a high economic efficiency. Animal feed facilities had a wide distribution of the total GHG emissions, depending on both the energy usage during the drying process and the substitution effect, which were related to the water content of the food waste and the number of recycled products. In comparison with incineration, the majority of the food recycling facilities showed low GHG emissions and economic
Takata, Miki; Fukushima, Kazuyo; Kino-Kimata, Noriko; Nagao, Norio; Niwa, Chiaki; Toda, Tatsuki
2012-08-15
In Japan, a revised Food Recycling Law went into effect in 2007 to promote a "recycling loop" that requires food industries to purchase farm products that are grown using food waste-derived compost/animal feed. To realize and expand food recycling, it is necessary to evaluate how the recycling facilities work in the recycling loop. The purpose of this study is to assess the environmental and economic efficiency of the food recycling facilities that are involved in the recycling loop, which are also known as looped facilities. The global warming potential and running cost of five looped facilities were evaluated by LCA (life cycle assessment) and LCC (life cycle cost) approaches: machine integrated compost, windrow compost, liquid feed, dry feed, and bio-gasification. The LCA results showed low total GHG (greenhouse gas) emissions of -126 and -49 kg-CO(2)/t-waste, respectively, for dry feed and bio-gasification facilities, due to a high substitution effect. The LCC study showed a low running cost for composting facilities of -15,648 and -18,955 yen/t-waste, respectively, due to high revenue from the food waste collection. It was found that the mandatory reporting of food waste emitters to the government increased collection fees; however, the collection fee in animal feed facilities was relatively low because food waste was collected at a low price or nutritious food waste was purchased to produce quality feed. In the characterisation survey of various treatment methods, the composting facilities showed a relatively low environmental impact and a high economic efficiency. Animal feed facilities had a wide distribution of the total GHG emissions, depending on both the energy usage during the drying process and the substitution effect, which were related to the water content of the food waste and the number of recycled products. In comparison with incineration, the majority of the food recycling facilities showed low GHG emissions and economic effectiveness. This
Analysis of the effects of time delay in clock recovery circuits based on Phase-locked loops
DEFF Research Database (Denmark)
Zibar, Darko; Oxenløwe, Leif Katsuo; Clausen, Anders
2004-01-01
Influence of time delay in a balanced optical phase-locked loops (OPLL) with a proportional integrator (Pl) filter is investigated using a delayed differential equation (DDE) is investigated. The limitations, which a time delay imposes on the Pl filter bandwidth, at increasing values of loop gain......, are investigated by numerical simulations. Furthermore, simple expressions governing the stability properties of the loop, in the presence of time delay, are derived. For this purpose, three standard loop filters are considered: a Pl filter, a low pass (LP) filter and an active lag (AL) filter. The derived...
Goodaire, EG; Polcino Milies, C
1996-01-01
For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri
International Nuclear Information System (INIS)
Zhao, G. Q.; Chen, L.; Wu, D. J.; Yan, Y. H.
2013-01-01
Solar type I radio storms are long-lived radio emissions from the solar atmosphere. It is believed that these type I storms are produced by energetic electrons trapped within a closed magnetic structure and are characterized by a high ordinary (O) mode polarization. However, the microphysical nature of these emissions is still an open problem. Recently, Wu et al. found that Alfvén waves (AWs) can significantly influence the basic physics of wave-particle interactions by modifying the resonant condition. Taking the effects of AWs into account, this work investigates electron cyclotron maser emission driven by power-law energetic electrons with a low-energy cutoff distribution, which are trapped in coronal loops by closed solar magnetic fields. The results show that the emission is dominated by the O mode. It is proposed that this O mode emission may possibly be responsible for solar type I radio storms.
Ototoxicity of loop diuretics.
Rybak, L P
1993-10-01
The loop diuretics are drugs that increase the excretion of water and electrolytes in the urine by their action on the cells in the loop of Henle. Clinical reports of ototoxicity of these agents are reviewed, and the results of a number of studies in experimental animals are discussed. These drugs can cause either a temporary, or in some cases, a permanent loss of hearing in patients. Animal experiments show that these drugs act on the stria vascularis, producing edema of these tissues and a temporary loss of function, resulting in a decrease of the endocochlear potential. This can result in secondary effects on sound-evoked measures of hearing. As new information unfolds about protective agents, it may be possible to preserve hearing and maintain the desired therapeutic effect.
International Nuclear Information System (INIS)
Takata, Miki; Fukushima, Kazuyo; Kino-Kimata, Noriko; Nagao, Norio; Niwa, Chiaki; Toda, Tatsuki
2012-01-01
In Japan, a revised Food Recycling Law went into effect in 2007 to promote a “recycling loop” that requires food industries to purchase farm products that are grown using food waste-derived compost/animal feed. To realize and expand food recycling, it is necessary to evaluate how the recycling facilities work in the recycling loop. The purpose of this study is to assess the environmental and economic efficiency of the food recycling facilities that are involved in the recycling loop, which are also known as looped facilities. The global warming potential and running cost of five looped facilities were evaluated by LCA (life cycle assessment) and LCC (life cycle cost) approaches: machine integrated compost, windrow compost, liquid feed, dry feed, and bio-gasification. The LCA results showed low total GHG (greenhouse gas) emissions of − 126 and − 49 kg-CO 2 /t-waste, respectively, for dry feed and bio-gasification facilities, due to a high substitution effect. The LCC study showed a low running cost for composting facilities of − 15,648 and − 18,955 yen/t-waste, respectively, due to high revenue from the food waste collection. It was found that the mandatory reporting of food waste emitters to the government increased collection fees; however, the collection fee in animal feed facilities was relatively low because food waste was collected at a low price or nutritious food waste was purchased to produce quality feed. In the characterisation survey of various treatment methods, the composting facilities showed a relatively low environmental impact and a high economic efficiency. Animal feed facilities had a wide distribution of the total GHG emissions, depending on both the energy usage during the drying process and the substitution effect, which were related to the water content of the food waste and the number of recycled products. In comparison with incineration, the majority of the food recycling facilities showed low GHG emissions and economic
Directory of Open Access Journals (Sweden)
Bojowald Martin
2008-07-01
Full Text Available Quantum gravity is expected to be necessary in order to understand situations in which classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical spacetime inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding spacetime is then modified. One particular theory is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. The main effects are introduced into effective classical equations, which allow one to avoid the interpretational problems of quantum theory. They give rise to new kinds of early-universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function, which allows an extension of quantum spacetime beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of spacetime arising in loop quantum gravity and its application to cosmology sheds light on more general issues, such as the nature of time.
Bojowald, Martin
2008-01-01
Quantum gravity is expected to be necessary in order to understand situations in which classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical spacetime inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding spacetime is then modified. One particular theory is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. The main effects are introduced into effective classical equations, which allow one to avoid the interpretational problems of quantum theory. They give rise to new kinds of early-universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function, which allows an extension of quantum spacetime beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of spacetime arising in loop quantum gravity and its application to cosmology sheds light on more general issues, such as the nature of time. Supplementary material is available for this article at 10.12942/lrr-2008-4.
Directory of Open Access Journals (Sweden)
Bojowald Martin
2005-12-01
Full Text Available Quantum gravity is expected to be necessary in order to understand situations where classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical space-time inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding space-time is then modified. One particular realization is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. Main effects are introduced into effective classical equations which allow to avoid interpretational problems of quantum theory. They give rise to new kinds of early universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function which allows to extend space-time beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of space-time arising in loop quantum gravity and its application to cosmology sheds new light on more general issues such as time.
Loop Transfer Matrix and Loop Quantum Mechanics
International Nuclear Information System (INIS)
Savvidy, George K.
2000-01-01
The gonihedric model of random surfaces on a 3d Euclidean lattice has equivalent representation in terms of transfer matrix K(Q i ,Q f ), which describes the propagation of loops Q. We extend the previous construction of the loop transfer matrix to the case of nonzero self-intersection coupling constant κ. We introduce the loop generalization of Fourier transformation which allows to diagonalize transfer matrices, that depend on symmetric difference of loops only and express all eigenvalues of 3d loop transfer matrix through the correlation functions of the corresponding 2d statistical system. The loop Fourier transformation allows to carry out the analogy with quantum mechanics of point particles, to introduce conjugate loop momentum P and to define loop quantum mechanics. We also consider transfer matrix on 4d lattice which describes propagation of memebranes. This transfer matrix can also be diagonalized by using the generalized Fourier transformation, and all its eigenvalues are equal to the correlation functions of the corresponding 3d statistical system. In particular the free energy of the 4d membrane system is equal to the free energy of 3d gonihedric system of loops and is equal to the free energy of 2d Ising model. (author)
Directory of Open Access Journals (Sweden)
Eva Nada
2015-03-01
Full Text Available This paper explores the process of the rationalization of activation policies towards unemployed young people in Switzerland. It aims at analysing the mechanism of normalization for the criterion of “unqualified” among unemployed young people with no qualifications. Empirical observations show the growing difficulties for personal counsellors to categorize an increasingly heterogeneous population of young unemployed people. These difficulties crystallize themselves with the definition of the criterion “unqualified”, thereby ushering in a new activation measure that appraises the school- and psychological aptitudes of young people. This measure partially determines the eligibility of the unemployed young people and participates in producing a norm of the “right measure” in relation to the level of “unqualification”. The concept of “looping effect “ developed by Ian Hacking was used to analyse the mechanism of transformation of the category and its effects on the identities of both young people and the front line agents. The paper discusses how to apply a philosophical concept to the sociology of categorization in order to deepen our understanding of activation policies within the changing scene of European social policy.
Kalmykov, M. Yu.; Pronin, P. I.; Stepanyantz, K. V.
1994-01-01
We investigate the influence of the projective invariance on the renormalization properties of the theory. One-loop counterterms are calculated in the most general case of interaction of gravity with scalar field.
Rück, Marlon; Reuther, Johannes
2018-04-01
We implement an extension of the pseudofermion functional renormalization group method for quantum spin systems that takes into account two-loop diagrammatic contributions. An efficient numerical treatment of the additional terms is achieved within a nested graph construction which recombines different one-loop interaction channels. In order to be fully self-consistent with respect to self-energy corrections, we also include certain three-loop terms of Katanin type. We first apply this formalism to the antiferromagnetic J1-J2 Heisenberg model on the square lattice and benchmark our results against the previous one-loop plus Katanin approach. Even though the renormalization group (RG) equations undergo significant modifications when including the two-loop terms, the magnetic phase diagram, comprising Néel ordered and collinear ordered phases separated by a magnetically disordered regime, remains remarkably unchanged. Only the boundary position between the disordered and the collinear phases is found to be moderately affected by two-loop terms. On the other hand, critical RG scales, which we associate with critical temperatures Tc, are reduced by a factor of ˜2 indicating that the two-loop diagrams play a significant role in enforcing the Mermin-Wagner theorem. Improved estimates for critical temperatures are also obtained for the Heisenberg ferromagnet on the three-dimensional simple cubic lattice where errors in Tc are reduced by ˜34 % . These findings have important implications for the quantum phase diagrams calculated within the previous one-loop plus Katanin approach which turn out to be already well converged.
Continuous-Flow Cardiac Assistance: Effects on Aortic Valve Function in a Mock Loop
Tuzun, Egemen; Rutten, Marcel; Dat, Marco; van de Vosse, Frans; Kadipasaoglu, Cihan; de Mol, Bas
2011-01-01
Background. As the use of left ventricular assist devices (LVADs) to treat end-stage heart failure has become more widespread, leaflet fusion-with resultant aortic regurgitation-has been observed more frequently. To quantitatively assess the effects of nonpulsatile flow on aortic valve function, we
International Nuclear Information System (INIS)
Banin, A.T.; Buchbinder, I.L.; Pletnev, N.G.
2003-01-01
We develop the derivative expansion of the one-loop N=4 super Yang-Mills (SYM) effective action depending both on the N=2 vector multiplet and on hypermultiplet background fields. Beginning with the formulation of N=4 SYM theory in terms of N=1 superfields, we construct the one-loop effective action with the help of superfield functional determinants and calculate this effective action in N=1 superfield form using the approximation of constant Abelian strength F mn and corresponding constant hypermultiplet fields. Then we show that the terms in the supercovariant derivative expansion of the effective action can be rewritten in terms of N=2 superfields. As a result, we get a new derivation of the complete N=4 supersymmetric low-energy effective action obtained by Buchbinder and Ivanov and find subleading corrections to it
International Nuclear Information System (INIS)
Lee, Keunsung; Choi, Sunmi; Kim, Eden
2016-01-01
The EU-APR design has been developed in order to expand and diversify the global nuclear power market of APR1400. For the improvement of shutdown risk for the EUAPR, the mid-loop level control system (MLCS) is considered during mid-loop operation for the EU-APR, which is not incorporated into SKN 3 and 4 (APR1400 Type) in Korea. Commonly, the risk associated with the NPP can be identified through the PSA. Thus, this paper discusses the low power and shutdown (LPSD) risk reduction effect by MLCS using the Low-Power and Shutdown PSA Result. LPSD level 1 PSA models for EU-APR have been developed. The risk reduction effect by MLCS is discussed. Because the loss of shutdown cooling function during mid-loop is one of the most vulnerable events, the MLCS have a significant influence on CDF in LPSD PSA. The shutdown risk of domestic power plants would likely be reduced if the MLCS is adopted in all operating NPPs in Korea during the mid-loop operation. It is expected that this work will contribute to reduce shutdown risk of domestic power plants
Directory of Open Access Journals (Sweden)
Kammuang-Lue Niti
2017-01-01
Full Text Available The objective of this study was to experimentally investigate the effects of working fluids and internal diameters on the thermal resistance of rotating closed-loop pul¬sating heat pipes (RCLPHP. The RCLPHP were made of a copper tube with internal diameters of 1.50 mm and 1.78 mm, bent into the shape of a flower petal, and arranged into a circle with 11 turns. The evaporator section was located at the outer end of the tube bundle. R123, ethanol, and water were filled as the working fluids. The RCLPHP was rotated at centrifugal accelerations 0.5, 1, 3, 5, 10, and 20 times of the gravitational acceleration considered at the connection between the evaporator and the condenser sections. The heat input was varied from 30 W to 50 W, and then to 100 W, 150 W, and 200 W. It can be concluded that when the latent heat of evaporation increases, the pressure difference between the evaporator and the condenser sections decreases, and the thermal resistance increases. Moreover, when the internal diameter increases, the driving force increases and the frictional force proportionally decreases, or the Karman number increases, and the thermal resistance decreases.
Energy Technology Data Exchange (ETDEWEB)
Ebrahimi, Zanyar; Karami, Kayoomars [Department of Physics, University of Kurdistan, Pasdaran Street, P.O. Box 66177-15175, Sanandaj (Iran, Islamic Republic of); Soler, Roberto, E-mail: z.ebrahimi@uok.ac.ir [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain)
2017-08-10
There is observational evidence for the existence of a twisted magnetic field in the solar corona. This inspires us to investigate the effect of a twisted magnetic field on the evolution of magnetohydrodynamic (MHD) kink waves in coronal loops. With this aim, we solve the incompressible linearized MHD equations in a magnetically twisted nonuniform coronal flux tube in the limit of long wavelengths. Our results show that a twisted magnetic field can enhance or diminish the rate of phase mixing of the Alfvén continuum modes and the decay rate of the global kink oscillation depending on the twist model and the sign of the longitudinal ( k{sub z} ) and azimuthal ( m ) wavenumbers. Also, our results confirm that in the presence of a twisted magnetic field, when the sign of one of the two wavenumbers m and k {sub z} is changed, the symmetry with respect to the propagation direction is broken. Even a small amount of twist can have an important impact on the process of energy cascading to small scales.
One-loop and D-instanton corrections to the effective action of open string models
Energy Technology Data Exchange (ETDEWEB)
Schmidt-Sommerfeld, Maximilian
2009-07-02
Methods for the calculation of certain corrections to effective actions, which comprehend the low-energy physics of string compactifications with open strings, are explained. First the shape of such actions is describes and some examples for compactifications are presented, especially a type I string model to which a dual model on the base of the heterotic string is known. Then corrections on the gauge coupling constant and on the gauge-kinetic function are discussed. general procedures for their calculation are sketched and applied to some models. The explicitly determinded corrections depend non-holomorphically on the moduli of the compactification manifold. It is explained that this is not in disagreement on the holomorphy of the gauge-kinetic function and how the latter can be extracted from the calculated results. Next D-instantons and their influence on the low-energy action are detailedly analyzed, whereby the zero modes of the instantons and global Abelian symmetries play a central role. A formula for the caclulation of scattering matrix elements in instanton sectors is given. It is to be expected that the considered instantons contribute to the superpotential of the low-energy action. However from the formula it becomes not immediately clear, how far this is possible. The mentioned formula seems to lead to expressions, which are in disagreement to the holomorphy of the superpotential. It is shown that non-holomorphic terms partly simplify, partly are so composed that the result is in accordance with the holomorphy of the superpotential. The D-instanton calculus is then used in order to derive the ADS superpotential, which is known from field theory. That this is possible is to be considered as successful test of the instanton calculus. D-instanton corrections to the gauge-kinetic functions are considered. S duality between the type I and the heterotic string is used in order to determine how the structure of the zero modes of the relevant instantons looks
Directory of Open Access Journals (Sweden)
Morrow Casey D
2007-01-01
Full Text Available Abstract Background Human immunodeficiency virus (HIV-1 exclusively selects and utilizes tRNALys,3 as the primer for initiation of reverse transcription. Several elements within the TΨC stem loop of tRNALys,3 are postulated to be important for selection and use in reverse transcription. The post-transcriptional modification at nucleotide 58 could play a role during plus-strand synthesis to stop reverse transcriptase from re-copying the tRNA primer. Nucleotides 53 and 54 within the TΨC stem loop of the tRNA have been shown to be important to form the complex between tRNA and the HIV-1 viral genome during initiation of reverse transcription. Results To further delineate the features of the TΨC stem loop of tRNALys,3 in reverse transcription, we have developed a complementation system in which E. coli tRNALys,3 is provided in trans to an HIV-1 genome in which the PBS is complementary to this tRNA. Successful selection and use of E. coli tRNALys,3 results in the production of infectious virus. We have used this single round infectious system to ascertain the effects that different mutants in the TΨC stem loop of tRNALys,3 have on complementation. Mutants were designed within the TΨC loop (nucleotide 58 and within the stem and loop of the TΨC loop (nucleotides 53 and 54. Analysis of the expression of E. coli tRNALys,3 mutants revealed differences in the capacity for aminoacylation, which is an indication of intracellular stability of the tRNA. Alteration of nucleotide 58 from A to U (A58U, T54G and TG5453CC all resulted in tRNALys,3 that was aminoacylated when expressed in cells, while a T54C mutation resulted in a tRNALys,3 that was not aminoacylated. Both the A58U and T54G mutated tRNALys,3 complemented HIV-1 replication similar to wild type E. coli tRNALys,3. In contrast, the TG5453CC tRNALys,3 mutant did not complement replication. Conclusion The results demonstrate that post-transcriptional modification of nucleotide 58 in tRNALys,3 is not
The effect of design and scale on the mixing and mass transfer in U-loop bioreactors
DEFF Research Database (Denmark)
Petersen, Leander Adrian Haaning; Villadsen, John; Jørgensen, Sten Bay
is altered? In this study we have investigated the mixing time and mass transfer capabilities of U-loop reactors of different geometries (high vs. diameter ratio) in pilot (0.15m3) and semi-industrial scales (2.2m3). A new expression for the mechanical power input into the system is also proposed, which...... vertical forced flow loop reactor where gas and liquid are driven through a series of static mixers in a U-shaped pipe, is quite capable of coping with these challenges in pilot scale. The critical question remains; what happens when the scale undergoes a more than 10 fold increase and the geometry...
The effect of design and scale on the mixing and mass transfer in U-loop bioreactors
Petersen, Leander Adrian Haaning; Villadsen, John; Jørgensen, Sten Bay; Christensen, Ib; Eliasson Lantz, Anna; Gernaey, Krist V.
2017-01-01
A system capable of handling a large volumetric gas fraction while providing a high gas to liquid mass transfer is a necessity if the metanotrophic bacterium Methylococcus capsulatus is to be used in single cell protein (SCP) production.Previous studies have proven that a U-loop fermenter, a novel vertical forced flow loop reactor where gas and liquid are driven through a series of static mixers in a U-shaped pipe, is quite capable of coping with these challenges in pilot scale. The critical ...
Goldfield, Gary S; Mallory, Risa; Parker, Torrey; Cunningham, Terrell; Legg, Christine; Lumb, Andrew; Parker, Kasey; Prud'homme, Denis; Gaboury, Isabelle; Adamo, Kristi B
2006-07-01
Television viewing and physical inactivity increase the risk of obesity in youth. Thus, identifying new interventions that increase physical activity and reduce television viewing would be helpful in the prevention and treatment of pediatric obesity. This study evaluated the effects of open-loop feedback plus reinforcement versus open-loop feedback alone on physical activity, targeted sedentary behavior, body composition, and energy intake in youth. Thirty overweight or obese 8- to 12-year-old children were randomly assigned to an intervention (n = 14) or control group (n = 16). Participants wore accelerometers every day for 8 weeks and attended biweekly meetings to download the activity monitors. For children in the open-loop feedback plus reinforcement (intervention) group, accumulating 400 counts of physical activity on pedometers earned 1 hour of television/VCR/DVD time, which was controlled by a Token TV electronic device. Open-loop feedback control subjects wore activity monitors but had free access to targeted sedentary behavior. Compared with controls, the open-loop feedback plus reinforcement group demonstrated significantly greater increases in daily physical activity counts (+65% vs +16%) and minutes per day of moderate-to-vigorous physical activity (+9.4 vs +0.3) and greater reductions in minutes per day spent in television viewing (-116.1 vs +14.3). The intervention group also showed more favorable changes in body composition, dietary fat intake, and energy intake from snacks compared with controls. Reductions in sedentary behavior were directly related to reductions in BMI, fat intake, snack intake, and snack intake while watching television. Providing feedback of physical activity in combination with reinforcing physical activity with sedentary behavior is a simple method of modifying the home environment that may play an important role in treating and preventing child obesity.
Thermodynamics in Loop Quantum Cosmology
International Nuclear Information System (INIS)
Li, L.F.; Zhu, J.Y.
2009-01-01
Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. Moreover, the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but also are actually found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid.
Fibular fracture stabilization with a guidewire as supplementary fixation in tibia fractures.
Dombroski, Derek; Scolaro, John A; Pulos, Nicholas; Beingessner, Daphne M; Dunbar, Robert; Mehta, Samir
2012-11-01
We present a novel technique of intramedullary fixation of the fibula using a humeral guide wire as an adjunct to tibial fixation, in the setting of tibial shaft fracture. Not only does this technique aid in determining length, alignment, and rotation of the tibial fracture, but it may also help the support of the lower extremity as whole by stabilizing the lateral column. In addition, this technique can be used to help maintain reduction of the fibula when there is concern for the soft tissues of the lower extremity secondary to swelling or injury. Our clinical case series demonstrates this safe, effective, and cost-sensitive technique to be used in the treatment of select concurrent fractures of the tibia and fibula.
International Nuclear Information System (INIS)
Wang, Wenjing; Li, Yingjie; Xie, Xin; Sun, Rongyue
2014-01-01
Highlights: • HCl improves CO 2 capture capacity of limestone in the previous a dozen cycles. • HCl sharply decreases limestone reactivity after a dozen cycles. • HCl intensifies effects of carbonation and calcination temperature on CO 2 capture. • HCl enlarges effects of particle size on CO 2 capture. • HCl severely aggravates the sintering of limestone after a dozen cycles. - Abstract: The effect of the presence of HCl on cyclic CO 2 capture behavior of calcium-based sorbent in the calcium looping process was investigated. When HCl was present in the carbonation atmosphere, the effects of carbonation temperature, calcination temperature, HCl concentration and particle size on CO 2 capture of the limestone in the multiple calcination/carbonation cycles were studied in a dual fixed-bed reactor. The presence of HCl in the carbonation atmosphere improves CO 2 capture capacity of the limestone in the previous a dozen cycles, but sharply decreases its reactivity with further increasing the cycle number above a dozen. The presence of HCl intensifies the effects of carbonation temperature and calcination temperature on CO 2 capture capacity of the limestone. The optimum carbonation temperature and the feasible calcination temperature for cyclic CO 2 capture of the limestone in the presence of HCl should be 700 °C and below 900 °C, respectively. The cyclic CO 2 capture capacity of the limestone in the previous a dozen cycles achieves the maximum in the presence of 300 ppm HCl with increasing the HCl concentration from 100 to 1000 ppm. The higher CO 2 capture capacity of the limestone is achieved with smaller particle size in the presence of HCl. The presence of HCl may destroy the compact CaCO 3 product layer and it is beneficial to CO 2 diffusion through the layer in the initial cycles. The chlorination conversion and the molten CaCl 2 –CaCO 3 product layer thickness of the limestone in the presence of HCl increase with the number of calcination
Leion, H.; Lyngfelt, A.; Mattisson, T.
Chemical-looping combustion (CLC) is a combustion technology where an oxygen carrier is used to transfer oxygen from the combustion air to the fuel in order to avoid direct contact between air and fuel. Thus, the CO2 is inherently separated from the flue gases with a potential for considerably lower energy penalty and cost compared to other techniques for CO2 separation. The oxygen carrier is circulated between two reactors, a fuel and an air reactor, where the flue gas from the air reactor contains oxygen depleted air and the flue gas from the fuel reactor contains mainly CO2 and H2O. The water can easily be condensed and the remaining CO2 can be transported for underground storage. Most of the prior work with CLC has focused on using natural gas and syngas as fuel and oxygen carrying material normally produced from pure chemicals. However, recent work on adapting the CLC process for solid fuels with ores and natural minerals as oxygen carrier shows promising results. This paper will present results from reactivity investigations in a laboratory fluidized-bed reactor system using previously investigated natural mineral ilmenite as oxygen carrier and a bituminous Colombian coal as fuel. Experiments were conducted at a temperature of 970°C with N2, steam, and/or CO2 in the fluidizing gas. Synergy effects between steam and CO2 on fuel conversion was noted. The results show that the fuel conversion was a roughly a factor 5 faster with steam as compared to CO2 in the fluidizing gas.
Tucker, Eric; D' Archangel, Jeffrey; Raschke, Markus B; Boreman, Glenn
2015-05-04
Mid-infrared scattering scanning near-field optical microscopy, in combination with far-field infrared spectroscopy, and simulations, was employed to investigate the effect of mutual-element coupling towards the edge of arrays of loop elements acting as frequency selective surfaces (FSSs). Two different square loop arrays on ZnS over a ground plane, resonant at 10.3 µm, were investigated. One array had elements that were closely spaced while the other array had elements with greater inter-element spacing. In addition to the dipolar resonance, we observed a new emergent resonance associated with the edge of the closely-spaced array as a finite size effect, due to the broken translational invariance.
Loop quantization as a continuum limit
International Nuclear Information System (INIS)
Manrique, Elisa; Oeckl, Robert; Weber, Axel; Zapata, Jose A
2006-01-01
We present an implementation of Wilson's renormalization group and a continuum limit tailored for loop quantization. The dynamics of loop-quantized theories is constructed as a continuum limit of the dynamics of effective theories. After presenting the general formalism we show as a first explicit example the 2D Ising field theory, an interacting relativistic quantum field theory with local degrees of freedom quantized by loop quantization techniques
Brown, R.
1982-01-01
Efforts are continued to develop digital filter compensation schemes for the correction of momentum gains observed in the closed loop simulation of the docking of two satellites using the 6 DOF motion system. Several filters that work well for small delays ( .100ms) and a non-preloaded probe are discussed.
Renormalization of loop functions for all loops
International Nuclear Information System (INIS)
Brandt, R.A.; Neri, F.; Sato, M.
1981-01-01
It is shown that the vacuum expectation values W(C 1 ,xxx, C/sub n/) of products of the traces of the path-ordered phase factors P exp[igcontour-integral/sub C/iA/sub μ/(x)dx/sup μ/] are multiplicatively renormalizable in all orders of perturbation theory. Here A/sub μ/(x) are the vector gauge field matrices in the non-Abelian gauge theory with gauge group U(N) or SU(N), and C/sub i/ are loops (closed paths). When the loops are smooth (i.e., differentiable) and simple (i.e., non-self-intersecting), it has been shown that the generally divergent loop functions W become finite functions W when expressed in terms of the renormalized coupling constant and multiplied by the factors e/sup -K/L(C/sub i/), where K is linearly divergent and L(C/sub i/) is the length of C/sub i/. It is proved here that the loop functions remain multiplicatively renormalizable even if the curves have any finite number of cusps (points of nondifferentiability) or cross points (points of self-intersection). If C/sub γ/ is a loop which is smooth and simple except for a single cusp of angle γ, then W/sub R/(C/sub γ/) = Z(γ)W(C/sub γ/) is finite for a suitable renormalization factor Z(γ) which depends on γ but on no other characteristic of C/sub γ/. This statement is made precise by introducing a regularization, or via a loop-integrand subtraction scheme specified by a normalization condition W/sub R/(C-bar/sub γ/) = 1 for an arbitrary but fixed loop C-bar/sub γ/. Next, if C/sub β/ is a loop which is smooth and simple except for a cross point of angles β, then W(C/sub β/) must be renormalized together with the loop functions of associated sets S/sup i//sub β/ = ]C/sup i/ 1 ,xxx, C/sup i//sub p/i] (i = 2,xxx,I) of loops C/sup i//sub q/ which coincide with certain parts of C/sub β/equivalentC 1 1 . Then W/sub R/(S/sup i//sub β/) = Z/sup i/j(β)W(S/sup j//sub β/) is finite for a suitable matrix Z/sup i/j
Marure, Pravinkumar S; Patil, Raju Umaji; Reddy, Sumitra; Prakash, Amit; Kshetrimayum, Nillachandra; Shukla, Rajeevkumar
2016-01-01
A common strategy to correct Class II malocclusions using a nonextraction protocol in children is to move the maxillary molars distally using molar distalization appliances, which usually derive their anchorage from maxillary premolars, causing mesialization of premolars and protrusion of incisors. To evaluate the skeletal, dental and soft tissue changes produced by three different distalizing appliances, namely, pendulum, K-loop, and distal jet appliances. Sixty-six children of mean age 14.13 years requiring molar distalization were divided into three groups: Group I (pendulum appliance), Group II (K-loop), and Group III (distal jet). Lateral cephalometric films were taken before and after 5 months of molar distalization and following cephalometric parameters were used to assess the effects of maxillary molar distalization, namely, anteroposterior skeletal (SNA/SNB/ANB), vertical skeletal (face height ratio/Frankfort-mandibular plane [FMA]/angle formed between Maxillary plane & Mandibular plane (MM)), interdental (overjet/overbite), maxillary dentoalveolar, and soft tissue parameters. There was no significant age difference between the three groups. In overall treatment changes among the three groups, the Anteroposterior skeletal changes were not statistically significant, vertically FMA angle increased by 1.79° ± 2.25° and overbite reduced by 2.38 ± 1.83 mm. The maxillary first molars were distalized by an average of 4.70 ± 3.01 mm (Upper 6 [U6] to pterygoid vertical [PTV]). The maxillary central incisor labial tipping increased to an average of 1.61 ± 2.73 mm and cant of upper lip increased by 3.40° ± 5.88° are statistically significant (P < 0.05). All three distalization techniques in growing children produced significant effects on anchor unit. There was an increase in FMA angle, significant bite opening, proclination of the maxillary incisors and increase in the cant of the upper lip.
Directory of Open Access Journals (Sweden)
Venkateswararao
2017-11-01
Full Text Available BACKGROUND Minimally-invasive tube thoracostomy made easy with a combination of thoracic ultrasound and small bore chest drain kits (12F to16F using guidewire technique. The present study is aimed at easy and safe insertion of small bore chest drains (12F to 16F using Seldinger technique under ultrasound guidance with least discomfort to the patient. Large bore chest drains of size >20F using blunt dissection technique is painful, difficult to place in thick chest walls and technically more demanding. Placing the drains blindly basing on chest x-ray image may sometimes injure the underlying lung. MATERIALS AND METHODS Present study included 21 cases, of which 12 cases (57.1% were of pleural effusion and 9 cases (42.8% were of pneumothorax. Thoracic ultrasound was utilised by the operator for all pleural effusions and for those cases of pneumothorax who were on ventilator before tube insertion. Small bore chest drains (12F to 16F designed for guidewire technique were used in the present study. RESULTS Complete and sustainable lung expansion was seen in 19 of 21 cases (90.4%. It failed in remaining 2 cases (9.5% who had complex empyemas and hepatic hydrothorax. Pleurodesis was attempted in 6 cases (28.5% using tetracycline injectable form with success rate of 90%. Patient tolerance was good with numeric pain rating score of 1 to 3 (range 0 to 10; 0 = no pain; 5 = moderate pain; 10 = worst possible pain. CONCLUSION Using small bore chest tubes of sizes 12F to 16F designed for guidewire technique of insertion and utilising thoracic ultrasound, while insertion made the procedure easy and safe, less painful and good tolerance from patient’s point of view. Complete and sustainable lung expansion was seen in 90.4% of cases and highly efficacious for spontaneous and iatrogenic pneumothorax and in noncomplex and malignant pleural effusions. The technique is less demanding and thoracic ultrasound knowledge can be easily learnt and a combination of this
DEFF Research Database (Denmark)
Niero, Monia; Hauschild, Michael Zwicky; Hoffmeyer, Simon Boas
2017-01-01
systems. We present a framework combining life cycle assessment (LCA) and the Cradle to CradleÂ® (C2C) certification program for the development of continuous loop packaging systems, which was conceived for aluminum cans in the context of the Carlsberg Circular Community. As a first step......, the environmentally optimal beverage packaging life cycle scenario is identified, both in terms of defined use and reuse. Second, the limiting factors are identified for the continuous use of materials in multiple loops, meeting the two requirements in the C2C certification process that address the material level (i.......e., "material health" and "material reutilization" criteria) and the "renewable energy" criterion. Then, alternative scenarios are built to meet C2C certification criteria, and LCA is used to quantify the environmental impacts of the resulting improvement strategies, for example, change in material composition...
Closing the Loop with Exercises
Altizer, Andy
2008-01-01
Conducting exercises provides a critical bridge between the theory of an Emergency Action Plan and its effective implementation. When conducted properly, exercises can fill the gap between training and after-action review to close the preparedness loop--before an actual emergency occurs. Often exercises are planned and conducted on campus based on…
Morbidity of temporary loop ileostomies
Bakx, R.; Busch, O. R. C.; Bemelman, W. A.; Veldink, G. J.; Slors, J. F. M.; van Lanschot, J. J. B.
2004-01-01
Background/Aims: A temporary loop ileostomy is constructed to protect a distal colonic anastomosis. Closure is usually performed not earlier than 8 - 12 weeks after the primary operation. During this period, stoma-related complications can occur and enhance the adverse effect on quality of life. The
Directory of Open Access Journals (Sweden)
Abhijeet Ashok Salunke
Full Text Available ABSTRACT CONTEXT: Hardware breakage during hip surgery can pose challenging and difficult problems for orthopedic surgeons. Apart from technical difficulties relating to retrieval of the broken hardware, complications such as adjacent joint arthritis and damage to neurovascular structures and major viscera can occur. Complications occurring during the perioperative period must be informed to the patient and proper documentation is essential. The treatment options must be discussed with the patient and relatives and the implant company must be informed about this untoward incident. CASE REPORT: We report a case of complete removal of the implant and then removal of the broken guidewire using a combination of techniques, including a cannulated drill bit, pituitary forceps and Kerrison rongeur. CONCLUSIONS: We suggest some treatment options and recommendations for preventing an avoidable surgical catastrophe.
International Nuclear Information System (INIS)
De Witt, R.; Jepson, B.E.; Schwind, R.A.
1975-01-01
Sulfur isotopes are continuously separated and enriched using a closed loop reflux system wherein sulfur dioxide (SO 2 ) is reacted with sodium hydroxide (NaOH) or the like to form sodium hydrogen sulfite (NaHSO 3 ). Heavier sulfur isotopes are preferentially attracted to the NaHSO 3 , and subsequently reacted with sulfuric acid (H 2 SO 4 ) forming sodium hydrogen sulfate (NaHSO 4 ) and SO 2 gas, which contains increased concentrations of the heavier sulfur isotopes. This heavy isotope enriched SO 2 gas is subsequently separated and the NaHSO 4 is reacted with NaOH to form sodium sulfate (Na 2 SO 4 ), which is subsequently decomposed in an electrodialysis unit to form the NaOH and H 2 SO 4 components, which are used in the aforesaid reactions thereby effecting sulfur isotope separation and enrichment without objectionable loss of feed materials. (U.S.)
On loop extensions and cohomology of loops
Benítez, Rolando Jiménez; Meléndez, Quitzeh Morales
2015-01-01
In this paper are defined cohomology-like groups that classify loop extensions satisfying a given identity in three variables for association identities, and in two variables for the case of commutativity. It is considered a large amount of identities. This groups generalize those defined in works of Nishigori [2] and of Jhonson and Leedham-Green [4]. It is computed the number of metacyclic extensions for trivial action of the quotient on the kernel in one particular case for left Bol loops a...
Neutron transport in irradiation loops (IRENE loop)
International Nuclear Information System (INIS)
Sarsam, Maher.
1980-09-01
This thesis is composed of two parts with different aspects. Part one is a technical description of the loop and its main ancillary facilities as well as of the safety and operational regulations. The measurement methods on the model of the ISIS reactor and on the loop in the OSIRIS reactor are described. Part two deals with the possibility of calculating the powers dissipated by each rod of the fuel cluster, using appropriate computer codes, not only in the reflector but also in the core and to suggest a method of calculation [fr
Zhai, Xiang; Go, Maybelle K; O'Donoghue, AnnMarie C; Amyes, Tina L; Pegan, Scott D; Wang, Yan; Loria, J Patrick; Mesecar, Andrew D; Richard, John P
2014-06-03
Two mutations of the phosphodianion gripper loop in chicken muscle triosephosphate isomerase (cTIM) were examined: (1) the loop deletion mutant (LDM) formed by removal of residues 170-173 [Pompliano, D. L., et al. (1990) Biochemistry 29, 3186-3194] and (2) the loop 6 replacement mutant (L6RM), in which the N-terminal hinge sequence of TIM from eukaryotes, 166-PXW-168 (X = L or V), is replaced by the sequence from archaea, 166-PPE-168. The X-ray crystal structure of the L6RM shows a large displacement of the side chain of E168 from that for W168 in wild-type cTIM. Solution nuclear magnetic resonance data show that the L6RM results in significant chemical shift changes in loop 6 and surrounding regions, and that the binding of glycerol 3-phosphate (G3P) results in chemical shift changes for nuclei at the active site of the L6RM that are smaller than those of wild-type cTIM. Interactions with loop 6 of the L6RM stabilize the enediolate intermediate toward the elimination reaction catalyzed by the LDM. The LDM and L6RM result in 800000- and 23000-fold decreases, respectively, in kcat/Km for isomerization of GAP. Saturation of the LDM, but not the L6RM, by substrate and inhibitor phosphoglycolate is detected by steady-state kinetic analyses. We propose, on the basis of a comparison of X-ray crystal structures for wild-type TIM and the L6RM, that ligands bind weakly to the L6RM because a large fraction of the ligand binding energy is utilized to overcome destabilizing electrostatic interactions between the side chains of E168 and E129 that are predicted to develop in the loop-closed enzyme. Similar normalized yields of DHAP, d-DHAP, and d-GAP are formed in LDM- and L6RM-catalyzed reactions of GAP in D2O. The smaller normalized 12-13% yield of DHAP and d-DHAP observed for the mutant cTIM-catalyzed reactions compared with the 79% yield of these products for wild-type cTIM suggests that these mutations impair the transfer of a proton from O-2 to O-1 at the initial
2005-01-01
sim tut Simulation Tutorial Interactive Media Element This interactive tutorial on MATLAB covers the For Loop and the While Loop functions. Examples are provided with step-by-step animated explanations. The interactions involve entering MATLAB instructions and observing the outcomes. Self-check questions are provided to help learners determine their level of understanding of the content presented. EC1010 Introduction to MATLAB
International Nuclear Information System (INIS)
Moeller, S.V.
1983-02-01
The procedures used to operate the water loop of the Institute of Nuclear Enginering (IEN) in Brazil are presented. The aim is to help future operators of the training water loop in the operation technique and in a better comprehension of the phenomena occured during the execution of an experience. (E.G.) [pt
Directory of Open Access Journals (Sweden)
Rovelli Carlo
2008-07-01
Full Text Available The problem of describing the quantum behavior of gravity, and thus understanding quantum spacetime, is still open. Loop quantum gravity is a well-developed approach to this problem. It is a mathematically well-defined background-independent quantization of general relativity, with its conventional matter couplings. Today research in loop quantum gravity forms a vast area, ranging from mathematical foundations to physical applications. Among the most significant results obtained so far are: (i The computation of the spectra of geometrical quantities such as area and volume, which yield tentative quantitative predictions for Planck-scale physics. (ii A physical picture of the microstructure of quantum spacetime, characterized by Planck-scale discreteness. Discreteness emerges as a standard quantum effect from the discrete spectra, and provides a mathematical realization of Wheeler’s “spacetime foam” intuition. (iii Control of spacetime singularities, such as those in the interior of black holes and the cosmological one. This, in particular, has opened up the possibility of a theoretical investigation into the very early universe and the spacetime regions beyond the Big Bang. (iv A derivation of the Bekenstein–Hawking black-hole entropy. (v Low-energy calculations, yielding n-point functions well defined in a background-independent context. The theory is at the roots of, or strictly related to, a number of formalisms that have been developed for describing background-independent quantum field theory, such as spin foams, group field theory, causal spin networks, and others. I give here a general overview of ideas, techniques, results and open problems of this candidate theory of quantum gravity, and a guide to the relevant literature.
Rovelli, Carlo
2008-01-01
The problem of describing the quantum behavior of gravity, and thus understanding quantum spacetime , is still open. Loop quantum gravity is a well-developed approach to this problem. It is a mathematically well-defined background-independent quantization of general relativity, with its conventional matter couplings. Today research in loop quantum gravity forms a vast area, ranging from mathematical foundations to physical applications. Among the most significant results obtained so far are: (i) The computation of the spectra of geometrical quantities such as area and volume, which yield tentative quantitative predictions for Planck-scale physics. (ii) A physical picture of the microstructure of quantum spacetime, characterized by Planck-scale discreteness. Discreteness emerges as a standard quantum effect from the discrete spectra, and provides a mathematical realization of Wheeler's "spacetime foam" intuition. (iii) Control of spacetime singularities, such as those in the interior of black holes and the cosmological one. This, in particular, has opened up the possibility of a theoretical investigation into the very early universe and the spacetime regions beyond the Big Bang. (iv) A derivation of the Bekenstein-Hawking black-hole entropy. (v) Low-energy calculations, yielding n -point functions well defined in a background-independent context. The theory is at the roots of, or strictly related to, a number of formalisms that have been developed for describing background-independent quantum field theory, such as spin foams, group field theory, causal spin networks, and others. I give here a general overview of ideas, techniques, results and open problems of this candidate theory of quantum gravity, and a guide to the relevant literature.
International Nuclear Information System (INIS)
Creatini, F; Di Marco, P; Filippeschi, S; Fioriti, D; Mameli, M
2015-01-01
In the last decade, the continuous development of electronics has pointed out the need for a change in mind with regard to thermal management. In the present scenario, Pulsating Heat Pipes (PHPs) are novel promising two-phase passive heat transport devices that seem to meet all present and future thermal requirements. Nevertheless, PHPs governing phenomena are quite unique and not completely understood. In particular, single closed loop PHPs manifest several drawbacks, mostly related to the reduction of device thermal performance and reliability, i.e. the occurrence of multiple operational quasi-steady states. The present research work proposes the application of an electric field as a technique to promote the circulation of the working fluid in a preferential direction and stabilize the device operation. The tested single closed loop PHP is made of a copper tube with an inner tube diameter equal to 2.00 mm and filled with pure ethanol (60% filling ratio). The electric field is generated by a couple of wire-shaped electrodes powered with DC voltage up to 20 kV and laid parallel to the longitudinal axis of the glass tube constituting the adiabatic section. Although the electric field intensity in the working fluid region is weakened both by the polarization phenomenon of the working fluid and by the interposition of the glass tube, the experimental results highlight the influence of the electric field on the device thermal performance and encourage the continuation of the research in this direction. (paper)
PONDEROMOTIVE ACCELERATION IN CORONAL LOOPS
Energy Technology Data Exchange (ETDEWEB)
Dahlburg, R. B.; Obenschain, K. [LCP and FD, Naval Research Laboratory, Washington, DC 20375 (United States); Laming, J. M. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Taylor, B. D. [AFRL Eglin AFB, Pensacola, FL 32542 (United States)
2016-11-10
Ponderomotive acceleration has been asserted to be a cause of the first ionization potential (FIP) effect, the well-known enhancement in abundance by a factor of 3–4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a “by-product” of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of coronal loops with an axial magnetic field from 0.005 to 0.02 T and lengths from 25,000 to 75,000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets, which act to heat the loop. As a consequence of coronal magnetic reconnection, small-scale, high-speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.
Trullàs, Joan Carles; Morales-Rull, José Luís; Casado, Jesús; Freitas Ramírez, Adriana; Manzano, Luís; Formiga, Francesc
2016-07-01
Fluid overload refractory to loop diuretic therapy can complicate acute or chronic heart failure (HF) management. The Safety and Efficacy of the Combination of Loop with Thiazide-type Diuretics in Patients with Decompensated Heart Failure (CLOROTIC) trial (Clinicaltrials.gov identifier NCT01647932) will test the hypothesis that blocking distal tubule sodium reabsorption with hydrochlorothiazide can antagonize the renal adaptation to chronic loop diuretic therapy and improve diuretic resistance. CLOROTIC is a randomized, placebo-controlled, double-blind, multicenter study. Three hundred and four patients with decompensated HF will be randomly assigned to receive hydrochlorothiazide or placebo in addition to a furosemide regimen. The main inclusion criteria are: age ≥18 years, history of chronic HF (irrespective of etiology and/or ejection fraction), admission for acute decompensation, and previous treatment with an oral loop diuretic for at least 1 month before randomization. The 2 coprimary endpoints are changes in body weight and changes in patient-reported dyspnea during hospital admission. Morbidity, mortality, and safety aspects will also be addressed. CLOROTIC is the first large-scale trial to evaluate whether the addition of a thiazide diuretic (hydrochlorothiazide) to a loop diuretic (furosemide) is a safe and effective strategy for improving congestive symptoms resulting from HF. This trial will provide important information and will therefore have a major impact on treatment strategies and future trials in these patients. Copyright © 2015 Elsevier Inc. All rights reserved.
Loop corrections to primordial non-Gaussianity
Boran, Sibel; Kahya, E. O.
2018-02-01
We discuss quantum gravitational loop effects to observable quantities such as curvature power spectrum and primordial non-Gaussianity of cosmic microwave background (CMB) radiation. We first review the previously shown case where one gets a time dependence for zeta-zeta correlator due to loop corrections. Then we investigate the effect of loop corrections to primordial non-Gaussianity of CMB. We conclude that, even with a single scalar inflaton, one might get a huge value for non-Gaussianity which would exceed the observed value by at least 30 orders of magnitude. Finally we discuss the consequences of this result for scalar driven inflationary models.
On the Kählerian symmetries of the two-loop action of the effective string theory
Ozkurt, S S
2003-01-01
Sometimes ago, it has been proposed in a paper by N.Kaloper and K.A.Meissner (\\PR {\\bf D56} (1997) 7940) that if one makes local redefinitions of fields, it does not change the equations of motion (in the redefined fields); however, this comment has not generally been accepted, namely, the redefined fields satisfy different equations of motion. For this reason, in this paper, it is proved that the whole action can be written as a square of the zeroth-order field equations. In this way, we show that any solution of the zeroth-order field equations, which has some K\\"{a}hler symmetry, at the same time, is also a solution of the two-loop equations.
Long, Shiwei; Cao, Xun; Sun, Guangyao; Li, Ning; Chang, Tianci; Shao, Zewei; Jin, Ping
2018-05-01
Vanadium dioxide (VO2) is one of the most well-known thermochromic materials, which exhibits a notable optical change from transparent to reflecting in the infrared region upon a metal-insulator phase transition. For practical applications, VO2 thin films should be in high crystalline quality to obtain a strong solar modulation ability (ΔTsol). Meanwhile, narrow hysteresis loops and robust ambient durability are also indispensable for sensitivity and long-lived utilization, respectively. In this work, a series of high-quality V2O3/VO2 bilayer structures were grown on quartz glass substrates by reactive magnetron sputtering. Basically, the bottom V2O3 acts as the buffer layer to improve the crystallinity of the top VO2, while the VO2 serves as the thermochromic layer to guarantee the solar modulation ability for energy-saving. We observed an obvious increase in ΔTsol of 76% (from 7.5% to 13.2%) for VO2 films after introducing V2O3 buffer layers. Simultaneously, a remarkable reduction by 79% (from 21.9 °C to 4.7 °C) in width of hysteresis loop was obtained when embedding 60 nm V2O3 buffer for 60 nm VO2. In addition, VO2 with non-stoichiometry of V2O3±x buffer demonstrates a broadening hysteresis loops width, which is derived from the lattice distortion caused by lattice imperfection. Finally, durability of VO2 has been significantly improved due to positive effects of V2O3 buffer layer. Our results lead to a comprehensive enhancement in crystallinity of VO2 and shed new light on the promotion of thermochromic property by homologous oxides for VO2.
Panteleon, Antonios E; Loutseiko, Mikhail; Steil, Garry M; Rebrin, Kerstin
2006-07-01
A continuous closed-loop insulin delivery system using subcutaneous insulin delivery was evaluated in eight diabetic canines. Continuous glucose profiles were obtained by extrapolation of blood glucose measurements. Insulin delivery rate was calculated, using a model of beta-cell insulin secretion, and delivered with a Medtronic MiniMed subcutaneous infusion pump. The model acts like a classic proportional-integral-derivative controller, delivering insulin in proportion to glucose above target, history of past glucose values, and glucose rate of change. For each dog, a proportional gain was set relative to the open-loop total daily dose (TDD) of insulin. Additional gains based on 0.5 x TDD and 1.5 x TDD were also evaluated (gain dose response). Control was initiated 4 h before the meal with a target of 6.7 mmol/l. At the time of the meal, glucose was similar for all three gains (6.0 +/- 0.3, 5.2 +/- 0.3, and 4.9 +/- 0.5 mmol/l for 0.5 x TDD, TDD, and 1.5 x TDD, respectively; P > 0.05) with near-target values restored at the end of experiments (8.2 +/- 0.9, 6.0 +/- 0.6, and 6.0 +/- 0.5, respectively). The peak postprandial glucose level decreased significantly with increasing gain (12.1 +/- 0.6, 9.6 +/- 1.0, and 8.5 +/- 0.6 mmol/l, respectively; P glycemic control within a range of gain.
Energy Technology Data Exchange (ETDEWEB)
Li, Huijuan; Diao, Xiaoxu; Li, Boyuan; Smidts, Carol; Bragg-Sitton, Shannon
2017-03-01
This paper studies the propagation and effects of faults of critical components that pertain to the secondary loop of a nuclear power plant found in Nuclear Hybrid Energy Systems (NHES). This information is used to design an on-line monitoring (OLM) system which is capable of detecting and forecasting faults that are likely to occur during NHES operation. In this research, the causes, features, and effects of possible faults are investigated by simulating the propagation of faults in the secondary loop. The simulation is accomplished by using the Integrated System Failure Analysis (ISFA). ISFA is used for analyzing hardware and software faults during the conceptual design phase. In this paper, the models of system components required by ISFA are initially constructed. Then, the fault propagation analysis is implemented, which is conducted under the bounds set by acceptance criteria derived from the design of an OLM system. The result of the fault simulation is utilized to build a database for fault detection and diagnosis, provide preventive measures, and propose an optimization plan for the OLM system.
... of tissue that protrude through the intestinal wall (diverticulosis) Certain medical conditions, including Crohn's disease, radiation enteritis, ... History of radiation therapy to the abdomen Diabetes Diverticulosis of the small intestine Complications A blind loop ...
National Research Council Canada - National Science Library
Heier, Jeffrey E
2008-01-01
...) processes via the Observe, Orient, Decide, and Act (OODA) Loop concept. As defined by Wikipedia, a mashup is a Website or application that combines the content from more than one source into an integrated presentation...
Dechanneling by dislocation loops
International Nuclear Information System (INIS)
Chalant, Gerard.
1976-09-01
Ion implantation always induces the creation of dislocation loops. When the damage profile is determined by a backscattering technique, the dechanneling by these loops is implicitely at the origin of these measurements. The dechanneling of alpha particles by dislocation loops produced by the coalescence of quenched-in vacancies in aluminium is studied. The dechanneling and the concentration of loops were determined simultaneously. The dechanneling width around dislocation was found equal to lambda=6A, both for perfect and imperfect loops having a mean diameter d=250A. In the latter case, a dechanneling probability chi=0.34 was determined for the stacking fault, in good agreement with previous determination in gold. A general formula is proposed which takes into account the variation of lambda with the curvature (or the diameter d) of the loops. Finally, by a series of isothermal anneals, the self-diffusion energy ΔH of aluminium was measured. The value obtained ΔH=1.32+-0.10eV is in good agreement with the values obtained by other methods [fr
Quantum hysteresis loops in microscopic system: The loop area as a ...
Indian Academy of Sciences (India)
Effects of non-zero temperatures are explored with reference to a symmetric double well potential. The barrier crossing or, relaxation rates are shown to correlate systematically with the area of the loop. The possible use of hysteresis loop area in designing ﬁeld parameters for optimal control is suggested.
Rahman, Md. Lutfor; Salsabil, Zaimaa; Yasmin, Nusrat; Nourin, Farah Nazifa; Ali, Mohammad
2016-07-01
This paper presents an experimental study of a closed loop Pulsating Heat Pipe (CLPHP) as the demand of smaller and effective heat transfer devices is increasing day by day. PHP is a two phase heat transfer device suited for heat transfer applications, especially suited for handling moderate to high heat fluxes in different applications. A copper made Pulsating Heat Pipe (PHP) of 250 mm length is used in this experimental work with 2 mm ID and 3 mm OD, closed end-to-end in 8 looped, evacuated and then partially filled with working fluids. The evaporation section is 50 mm, adiabatic section is 120 mm and condensation section is 80 mm. The performance characterization is done for two working fluids at Vertical (0°) orientations. The working fluids are Methanol and Ethanol and the filling ratios are 40%, 50%, 60% & 70% based on total volume, respectively. The results show that the influence of various parameters, the heat input flux, and different filling ratios on a heat transfer performance of CLPHP. Methanol shows better performance as working fluid in PHP than ethanol at present orientation for a wide range of heat inputs and can be used at high heat input conditions. Ethanol is better choice to be used in low heat input conditions.
Brewer, Matt T; Xiong, Nalee; Anderson, Kristi L; Carlson, Steve A
2013-08-01
To assess antimicrobial resistance and transfer of virulence genes facilitated by subtherapeutic concentrations of antimicrobials in swine intestines. 20 anesthetized pigs experimentally inoculated with donor and recipient bacteria. 4 recipient pathogenic bacteria (Salmonella enterica serotype Typhimurium, Yersinia enterocolitica, Shigella flexneri, or Proteus mirabilis) were incubated with donor bacteria in the presence of subinhibitory concentrations of 1 of 16 antimicrobials in isolated ligated intestinal loops in swine. Donor Escherichia coli contained transferrable antimicrobial resistance or virulence genes. After coincubations, intestinal contents were removed and assessed for pathogens that acquired new antimicrobial resistance or virulence genes following exposure to the subtherapeutic concentrations of antimicrobials. 3 antimicrobials (apramycin, lincomycin, and neomycin) enhanced transfer of an antimicrobial resistance plasmid from commensal E coli organisms to Yersinia and Proteus organisms, whereas 7 antimicrobials (florfenicol, hygromycin, penicillin G, roxarsone, sulfamethazine, tetracycline, and tylosin) exacerbated transfer of an integron (Salmonella genomic island 1) from Salmonella organisms to Yersinia organisms. Sulfamethazine induced the transfer of Salmonella pathogenicity island 1 from pathogenic to nonpathogenic Salmonella organisms. Six antimicrobials (bacitracin, carbadox, erythromycin, sulfathiazole, tiamulin, and virginiamycin) did not mediate any transfer events. Sulfamethazine was the only antimicrobial implicated in 2 types of transfer events. 10 of 16 antimicrobials at subinhibitory or subtherapeutic concentrations augmented specific antimicrobial resistance or transfer of virulence genes into pathogenic bacteria in isolated intestinal loops in swine. Use of subtherapeutic antimicrobials in animal feed may be associated with unwanted collateral effects.
Loop facility for LM-MHD study
International Nuclear Information System (INIS)
Pan Chuanjie; Xu Zengyu; Zhao Li; Zhang Xiujie
2007-01-01
A loop facility, namely, New Liquid Metal Experimental Loop (NLMEL), was built in 2007 in SWIP, Which can be used to carry out the experimental investigation on the liquid metal (LM) MHD effects, such as MHD effects of liquid divertor and liquid blanket. The working fluid in the loop is Ga 68 In 20 Sn 12 alloy, which the melting point is 10.7 degree C, the density 6363 kg/m 3 , the electrical resistivity 3.3074 x 10 6 Ω·m -1 , the surface tension 0.353 N·m -1 , the dynamical viscosity 4.0 x 10 -7 m 2 /s at 20 degree C, and its chemical properties is not active. The loop facility consists of two three-phase alternating current(AC) electromagnetic (EM) pumps, dump tank, pump tank, expansion tank, calibrated flowmeter tank, EM flowmeter, electromagnet, MHD test section and its auxiliary system. Two experimental loops, namely, free surface jet flow and duct flow, were designed and installed at the experimental region of the uniform magnetic field in loop facility. The MHD experiment of liquid divertor can be carried out in free surface jet flow loop, and the MHD experimental for liquid blanket, such as MHD effect experiment in rectangular duct with FCI, can be carried out in duct flow loop. The rated voltage of two EM pumps is 380 V, the work temperature less than 500 degree C, electric current 14 and 6 A, fluid flux 11 and 4.7 m 3 /h, outlet pressure less than 6 x 10 5 and 5 x 10 5 Pa, respectively. A 12-ton electromagnet can provide the transverse magnetic field from 0 to 2.0 Tesla, and the uniform magnetic field space of 700 x 140 x 80. Total resistance of electromagnet coils is 1.5 Ω at 20 degree C. High-quality Direct Current (DC) Power supply can provide 0-200 A DC, and 0-60 kW power, the stability of current less than 1%, AC ripple factor less than 1%. Auxiliary systems include: oil cooling loop for cooling electromagnet and two EM pumps, and high purity argon device for protect gas of loop, and pumping vacuum device for loop devices, and electric device
Looping in OLSRv2 in Mobile Ad-Hoc Networks, Loop Suppression and Loop Correction
Speakman, Lee; Owada, Yasunori; Mase, Kenichi
Transient routing loops have been observed to form in Mobile Ad-hoc Networks running the OLSRv2 proactive link-state routing protocol. The packets falling into loops impact the surrounding network thus degrading throughput even though only a small proportion of the traffic may enter these loops and only for a short time. This becomes significantly more evident when Link Layer Notification is used to catch broken links, inadvertently leading to an increase in the number of loops. Two methods of Loop Detection are introduced and are used to trigger either Loop Suppression by selectively and preemptively discarding the looping packets that are unlikely to reach their destination, or Loop Correction by the notification of the routing protocol to cut the link over which the packet is looping. The newly introduced Loop Suppression and Loop Correction techniques used with Link Layer Notification are shown to significantly increase network performance over plain OLSRv2 and OLSRv2 with Link Layer Notification.
Palazzuoli, Alberto; Pellegrini, Marco; Franci, Beatrice; Beltrami, Matteo; Ruocco, Gaetano; Gonnelli, Stefano; Angelini, Gianni D; Nuti, Ranuccio
2015-02-01
Intravenous loop diuretics are still the cornerstone of therapy in acute decompensated heart failure, however, the optimal dosage and administration strategies remain poorly defined particularly in patients with an associated renal dysfunction. This is a single-center, pilot, randomized trial involving patients with acute HF and renal dysfunction. Patients were assigned to receive continuous furosemide infusion (cIV) or bolus injections of furosemide (iIV). Primary end points were the evaluation of urine output volumes, renal function, and b-type natriuretic peptide (BNP) levels during treatment time. Secondary end point included: weight loss, length of hospitalization, differences in plasma electrolytes, need for additional treatment, and evaluation of cardiac events during follow-up period. 57 patients were included in the study. The cIV group showed an increase in urine output (2,505 ± 796 vs 2140 ± 468 ml/day, p diuretics are responsible for worsening renal function and to define the best modality of administration.
Bacqué-Cazenave, Julien; Chung, Bryce; Cofer, David W; Cattaert, Daniel; Edwards, Donald H
2015-03-15
Neuromechanical simulation was used to determine whether proposed thoracic circuit mechanisms for the control of leg elevation and depression in crayfish could account for the responses of an experimental hybrid neuromechanical preparation when the proprioceptive feedback loop was open and closed. The hybrid neuromechanical preparation consisted of a computational model of the fifth crayfish leg driven in real time by the experimentally recorded activity of the levator and depressor (Lev/Dep) nerves of an in vitro preparation of the crayfish thoracic nerve cord. Up and down movements of the model leg evoked by motor nerve activity released and stretched the model coxobasal chordotonal organ (CBCO); variations in the CBCO length were used to drive identical variations in the length of the live CBCO in the in vitro preparation. CBCO afferent responses provided proprioceptive feedback to affect the thoracic motor output. Experiments performed with this hybrid neuromechanical preparation were simulated with a neuromechanical model in which a computational circuit model represented the relevant thoracic circuitry. Model simulations were able to reproduce the hybrid neuromechanical experimental results to show that proposed circuit mechanisms with sensory feedback could account for resistance reflexes displayed in the quiescent state and for reflex reversal and spontaneous Lev/Dep bursting seen in the active state. Copyright © 2015 the American Physiological Society.
Kühn, Johanna; Haumesser, Jens K; Beck, Maximilian H; Altschüler, Jennifer; Kühn, Andrea A; Nikulin, Vadim V; van Riesen, Christoph
2017-12-01
The current pharmacotherapy of Parkinson's disease (PD) is primarily based on two classes of drugs: dopamine precursors, namely levodopa, and dopamine receptor agonists, such as apomorphine. Although both types of agents exert their beneficial clinical effects on motor and non-motor symptoms in PD via dopamine receptors, clinical efficiency and side effects differ substantially between levodopa and apomorphine. Levodopa can provide a greater symptomatic relief than dopamine receptor agonists. However, because long-term levodopa use is associated with early debilitating motor fluctuations, dopamine receptor agonists are often recommended in younger patients. The pharmacodynamic basis of these profound differences is incompletely understood. It has been hypothesized that levodopa and dopamine receptor agonists may have diverging effects on beta and gamma oscillations that have been shown to be of importance for the pathophysiology of PD. Here, we used electrophysiological recordings in anesthetized dopamine-intact and dopamine-depleted rats to systemically compare the impact of levodopa or apomorphine on neuronal population oscillations in three nodes of the cortico-basal ganglia loop circuit. Our results showed that levodopa had a higher potency than apomorphine to suppress the abnormal beta oscillations often associated with bradykinesia while simultaneously enhancing the gamma oscillations often associated with increased movement. Our data suggests that the higher clinical efficacy of levodopa as well as some of its side effects, as e.g. dyskinesias may be based on its characteristic ability to modulate beta-/gamma-oscillation dynamics in the cortico-basal ganglia loop circuit. Copyright © 2017 Elsevier Inc. All rights reserved.
Development of 2-loop feedwater control system
International Nuclear Information System (INIS)
Omori, Takashi; Watanabe, Takao; Hirose, Masao.
1981-01-01
A 2-loop feedwater control system has been developed for automatic transfer control of the reactor feed pumps (RFP's) in BWR plants. This system consists of a master level controller and sub-loop flow controllers for each of the RFP's. Control characteristics of the 2-loop control system were investigated using a dynamic analysis code for the condensate feedwater system. Although the RFP system has a hydraulic coupling effect, the flow control loops become stable by setting adequate controller gains in the sub-loop flow controllers. The control characteristics in the major loop were modified in their initial response to level setpoint change by using a lead/lag compensator. Moreover, reactor core cooling was protected sufficiently during the transient in a trip of a turbine driven RFP. From simulation results of the transfer controls from the motor driven RFP to turbine driven RFP, it was ascertained that the 2-loop control system has such advantages as shorter completion time and superior controllability against ON-OFF action of a RFP recirculation valve during transfer control. (author)
Loop Diuretics in the Treatment of Hypertension.
Malha, Line; Mann, Samuel J
2016-04-01
Loop diuretics are not recommended in current hypertension guidelines largely due to the lack of outcome data. Nevertheless, they have been shown to lower blood pressure and to offer potential advantages over thiazide-type diuretics. Torsemide offers advantages of longer duration of action and once daily dosing (vs. furosemide and bumetanide) and more reliable bioavailability (vs. furosemide). Studies show that the previously employed high doses of thiazide-type diuretics lower BP more than furosemide. Loop diuretics appear to have a preferable side effect profile (less hyponatremia, hypokalemia, and possibly less glucose intolerance). Studies comparing efficacy and side effect profiles of loop diuretics with the lower, currently widely prescribed, thiazide doses are needed. Research is needed to fill gaps in knowledge and common misconceptions about loop diuretic use in hypertension and to determine their rightful place in the antihypertensive arsenal.
One-loop anisotropy for improved actions
Perez, Margarita Garcia; van Baal, Pierre
1996-01-01
We determine the one-loop correction to the anisotropy factor for the square Symanzik improved lattice action, extracted fromthe finite volume effective action for SU(N) gauge theories in the background of a zero-momentum gauge field. The result is smaller by approximately a factor 3 than the one-loop correction for the anisotropic Wilson action. We also comment on the Hamiltonian limit.
Luger, Maria; Kruschitz, Renate; Langer, Felix; Prager, Gerhard; Walker, Melanie; Marculescu, Rodrig; Hoppichler, Friedrich; Schindler, Karin; Ludvik, Bernhard
2015-06-01
Bariatric patients often suffer from nutrient deficiencies. Little is known about vitamin D levels and bone metabolism in patients undergoing omega-loop gastric bypass (OLGB). We, therefore, evaluated parameters of vitamin D metabolism preoperatively and during the first postoperative year. Within our cohort study, we retrospectively evaluated the respective parameters pre-, 3, 6, and 12 months postoperatively in patients with OLGB, between February 2011 and February 2013. In patients [n = 50; age 46 (15) years, mean (SD); 12 male, 38 female] BMI was 45.4 (6.6) kg/m(2) preoperatively and decreased to 29.1 (3.8) kg/m(2) after 12 months, corresponding to a total body weight loss of 36 %. Preoperatively, the prevalence of vitamin D deficiency was 96 and 30 % demonstrated elevated parathyroid hormone yielding a prevalence of secondary hyperparathyroidism of 17 %. Postoperatively, subjects received individually adjusted vitamin D3 supplementation (95 % CI 200-3000 IU/day), according to the available guidelines at that time. Nevertheless, every third patient was vitamin D deficient at 12 months (80 %). In patients with preoperative BMI >45 vs. deficiency over 12 months [OR = 3.10, 95 % CI (1.01-9.51), p = 0.048]. To avoid vitamin D deficiency, morbidly obese patients, particularly those with higher preoperative BMI, should be regularly screened pre- and postoperatively. Standard postsurgical supplementation has not been adequate to restore 25-OHD status and current guidelines are not very specific in terms of timing and dosing of vitamin D3 supplementation. Consequently, further trials to enhance the evidence on vitamin D supplementation are warranted.
Kilic, Teoman; Sahin, Tayfun; Ural, Ertan
2014-04-01
Percutaneous closure of paravalvular leaks has emerged as an alternative to repeated surgeries. Different percutaneous techniques and various devices have been used, off-label, for paravalvular leak closure. For mitral leaks, antegrade transseptal, retrograde transfemoral, and retrograde transapical techniques have been developed. In the antegrade transseptal approach, an arteriovenous guidewire loop is often created to advance the delivery sheath. In retrograde transfemoral closure, the wire in the left atrium is usually snared after transseptal puncture, to pull it from the femoral vein. The delivery sheath and closure device will subsequently be deployed from the left atrium. Each of these procedures takes time, is costly, and increases the risk of complications. We present the cases of 3 patients in whom we closed mitral paravalvular leaks by means of a retrograde transfemoral approach, with use of an Amplatzer™ Duct Occluder II device and without the construction of an arteriovenous wire loop. We think that this approach can be very useful in a specific group of patients-reducing costs, fluoroscopy times, and complications related to transseptal puncture and construction of an arteriovenous wire loop. In our institution, this reported technique is routinely used for mitral paravalvular leak closure.
Closed-Loop Neuromorphic Benchmarks
Directory of Open Access Journals (Sweden)
Terrence C Stewart
2015-12-01
Full Text Available Evaluating the effectiveness and performance of neuromorphic hardware is difficult. It is evenmore difficult when the task of interest is a closed-loop task; that is, a task where the outputfrom the neuromorphic hardware affects some environment, which then in turn affects thehardware’s future input. However, closed-loop situations are one of the primary potential uses ofneuromorphic hardware. To address this, we present a methodology for generating closed-loopbenchmarks that makes use of a hybrid of real physical embodiment and a type of minimalsimulation. Minimal simulation has been shown to lead to robust real-world performance, whilestill maintaining the practical advantages of simulation, such as making it easy for the samebenchmark to be used by many researchers. This method is flexible enough to allow researchersto explicitly modify the benchmarks to identify specific task domains where particular hardwareexcels. To demonstrate the method, we present a set of novel benchmarks that focus on motorcontrol for an arbitrary system with unknown external forces. Using these benchmarks, we showthat an error-driven learning rule can consistently improve motor control performance across arandomly generated family of closed-loop simulations, even when there are up to 15 interactingjoints to be controlled.
Burgess, Malcolm A.; Thomas, Rickey P.
2004-01-01
This experiment investigated improvements to cockpit weather displays to better support the hazardous weather avoidance decision-making of general aviation pilots. Forty-eight general aviation pilots were divided into three equal groups and presented with a simulated flight scenario involving embedded convective activity. The control group had access to conventional sources of pre-flight and in-flight weather products. The two treatment groups were provided with a weather display that presented NEXRAD mosaic images, graphic depiction of METARs, and text METARs. One treatment group used a NEXRAD image looping feature and the second group used the National Convective Weather Forecast (NCWF) product overlaid on the NEXRAD display. Both of the treatment displays provided a significant increase in situation awareness but, they provided incomplete information required to deal with hazardous convective weather conditions, and would require substantial pilot training to permit their safe and effective use.
DEFF Research Database (Denmark)
Prosman, Ernst-Jan; Wæhrens, Brian Vejrum; Liotta, Giacomo
2017-01-01
Replacing virgin materials with waste materials, a practice known as Industrial Symbiosis (IS), has been identified as a key strategy for closing material loops. This article adopts a critical view on geographic proximity and external coordinators – two key enablers of IS. By ‘uncovering’ a case ...... for geographic proximity and external coordinators. In doing so, our insights into firm-level challenges of long-distance IS exchanges contribute to closing global material loops by increasing the number of potential circular pathways....
Closed Loop Subspace Identification
Directory of Open Access Journals (Sweden)
Geir W. Nilsen
2005-07-01
Full Text Available A new three step closed loop subspace identifications algorithm based on an already existing algorithm and the Kalman filter properties is presented. The Kalman filter contains noise free states which implies that the states and innovation are uneorre lated. The idea is that a Kalman filter found by a good subspace identification algorithm will give an output which is sufficiently uncorrelated with the noise on the output of the actual process. Using feedback from the output of the estimated Kalman filter in the closed loop system a subspace identification algorithm can be used to estimate an unbiased model.
Xu, S T; Ma, Y Q; Zheng, G H; Dai, Z X
2015-04-21
Well-dispersed uniform cobalt ferrite nanoparticles were synthesized by thermal decomposition of a metal-organic salt in organic solvent with a high boiling point. Some of the nanoparticles were diluted in a SiO2 matrix and then the undiluted and diluted samples were characterized and their magnetic behavior explored. The undiluted and diluted samples exhibited maximum coercivity Hc of 23,817 and 15,056 Oe at 10 K, respectively, which are the highest values reported to date, and the corresponding ratios of remanence (Mr) to saturation (Ms) magnetization (Mr/Ms) were as high as 0.85 and 0.76, respectively. Interestingly, the magnetic properties of the samples changed at 200 K, which was observed in magnetic hysteresis M(H) loops and zero-field cooling curves as well as the temperature dependence of Hc, Mr/Ms, anisotropy, dipolar field, and the magnetic grain size. Below 200 K, both samples have large effective anisotropy, which arises from the surface spins, resulting in large Hc and Mr/Ms. Above 200 K, the effective anisotropy decreases because there is no contribution from surface spins, while the dipolar interaction increases, resulting in small Hc and Mr/Ms. Our results indicate that strong anisotropy and weak dipolar interaction tend to increase Hc and Mr/Ms, and also clarify that the jumps around H = 0 in M(H) loops can be attributed to the reorientation of surface spins. This work exposes the underlying mechanism in nanoscale magnetic systems, which should lead to improved magnetic performance.
Directory of Open Access Journals (Sweden)
Rovelli Carlo
1998-01-01
Full Text Available The problem of finding the quantum theory of the gravitational field, and thus understanding what is quantum spacetime, is still open. One of the most active of the current approaches is loop quantum gravity. Loop quantum gravity is a mathematically well-defined, non-perturbative and background independent quantization of general relativity, with its conventional matter couplings. Research in loop quantum gravity today forms a vast area, ranging from mathematical foundations to physical applications. Among the most significant results obtained are: (i The computation of the physical spectra of geometrical quantities such as area and volume, which yields quantitative predictions on Planck-scale physics. (ii A derivation of the Bekenstein-Hawking black hole entropy formula. (iii An intriguing physical picture of the microstructure of quantum physical space, characterized by a polymer-like Planck scale discreteness. This discreteness emerges naturally from the quantum theory and provides a mathematically well-defined realization of Wheeler's intuition of a spacetime ``foam''. Long standing open problems within the approach (lack of a scalar product, over-completeness of the loop basis, implementation of reality conditions have been fully solved. The weak part of the approach is the treatment of the dynamics: at present there exist several proposals, which are intensely debated. Here, I provide a general overview of ideas, techniques, results and open problems of this candidate theory of quantum gravity, and a guide to the relevant literature.
Justification by Infinite Loops
Peijnenburg, A.J.M.; Atkinson, David
2010-01-01
In an earlier paper we have shown that a proposition can have a well-defined probability value, even if its justification consists of an infinite linear chain. In the present paper we demonstrate that the same holds if the justification takes the form of a closed loop. Moreover, in the limit that
Improving Loop Dependence Analysis
DEFF Research Database (Denmark)
Jensen, Nicklas Bo; Karlsson, Sven
2017-01-01
Programmers can no longer depend on new processors to have significantly improved single-thread performance. Instead, gains have to come from other sources such as the compiler and its optimization passes. Advanced passes make use of information on the dependencies related to loops. We improve th...
Nanoscale dislocation shear loops at static equilibrium and finite temperature
Dang, Khanh; Capolungo, Laurent; Spearot, Douglas E.
2017-12-01
Atomistic simulations are used to determine the resolved shear stress necessary for equilibrium and the resulting geometry of nanoscale dislocation shear loops in Al. Dislocation loops with different sizes and shapes are created via superposition of elemental triangular dislocation displacement fields in the presence of an externally imposed shear stress. First, a bisection algorithm is developed to determine systematically the resolved shear stress necessary for equilibrium at 0 K. This approach allows for the identification of dislocation core structure and a correlation between dislocation loop size, shape and the computed shear stress for equilibrium. It is found, in agreement with predictions made by Scattergood and Bacon, that the equilibrium shape of a dislocation loop becomes more circular with increasing loop size. Second, the bisection algorithm is extended to study the influence of temperature on the resolved shear stress necessary for stability. An approach is presented to compute the effective lattice friction stress, including temperature dependence, for dislocation loops in Al. The temperature dependence of the effective lattice friction stress can be reliably computed for dislocation loops larger than 16.2 nm. However, for dislocation loops smaller than this threshold, the effective lattice friction stress shows a dislocation loop size dependence caused by significant overlap of the stress fields on the interior of the dislocation loops. Combined, static and finite temperature atomistic simulations provide essential data to parameterize discrete dislocation dynamics simulations.
Su, Chieh-Shou; Lai, Hui-Chin; Wang, Chih-Yen; Lee, Wen-Lieng; Wang, Kuo-Yang; Yang, Ya-Ling; Wang, Li-Chun; Liu, Chia-Ning; Liu, Tsun-Jui
2016-01-18
Tracheal intubation of laboratory mice remains essential yet challenging for most researchers. The aim of this study was to investigate whether this procedure can be more efficiently and safely accomplished by a novel method using slim and torqueable guidewires to guide access to the trachea. This study was carried out in an animal laboratory affiliated to a tertiary medical center. Mice weighing 22 to 28 g were subjected to various open-chest experiments after being anesthetized with intraperitoneal ketamine (100 mg/kg) and lidocaine hydrochloride (10 mg/kg). The oropharyngeal cavity was opened with angled tissue forceps, and the trachea was transilluminated using an external light. The vocal cords were then crossed using either the Conventional method with a 38-mm-long, end-blunted stiff needle as a guide for insertion of a 22-gauge, 25-mm-long intravenous catheter into the trachea, or the Modified method utilizing using a 0.014-inch-thin torqueable wire as the guide to introduce an identical tube over it into the trachea. The epithelial integrity of the trachea was later examined histologically when the animals were sacrificed either immediately after the surgery or at 28 days post-surgery, depending on the corresponding research protocols. Orotracheal intubation was successfully completed in all mice using either the Conventional (N = 42) or the Modified method (N = 50). With the Modified method, intubation took less time (1.73 vs. 2.17 min, Modified vs. Conventional, p Conventional method. Histological analysis revealed a significantly lower incidence of immediate (0% vs. 39%, p Conventional method. Tracheal intubation for laboratory mice can be completed efficiently, safely and atraumatically using the proposed Modified method employing readily available inexpensive instruments.
Dassau, E; Atlas, E; Phillip, M
2010-02-01
The dream of closing the loop is actually the dream of creating an artificial pancreas and freeing the patients from being involved with the care of their own diabetes. Insulin-dependent diabetes (type 1) is a chronic incurable disease which requires constant therapy without the possibility of any 'holidays' or insulin-free days. It means that patients have to inject insulin every day of their life, several times per day, and in order to do it safely they also have to measure their blood glucose levels several times per day. Patients need to plan their meals, their physical activities and their insulin regime - there is only very small room for spontaneous activities. This is why the desire for an artificial pancreas is so strong despite the fact that it will not cure the diabetic patients. Attempts to develop a closed-loop system started in the 1960s but never got to a clinical practical stage of development. In recent years the availability of continuous glucose sensors revived those efforts and stimulated the clinician and researchers to believe that closing the loop might be possible nowadays. Many papers have been published over the years describing several different ideas on how to close the loop. Most of the suggested systems have a sensing arm that measures the blood glucose repeatedly or continuously, an insulin delivery arm that injects insulin upon command and a computer that makes the decisions of when and how much insulin to deliver. The differences between the various published systems in the literature are mainly in their control algorithms. However, there are also differences related to the method and site of glucose measurement and insulin delivery. SC glucose measurements and insulin delivery are the most studied option but other combinations of insulin measurements and glucose delivery including intravascular and intraperitoneal (IP) are explored. We tried to select recent publications that we believe had influenced and inspired people interested
National Research Council Canada - National Science Library
Schulze, R
1965-01-01
.... 4) Determine the corrosion and mass transfer which occurred during operation of the The centrifugal pump was evaluated separately from the loop for its ability to accept both single bubbles of hydrogen...
Thurston, David E; Vassoler, Higia; Jackson, Paul J M; James, Colin H; Rahman, Khondaker M
2015-04-07
The pyrrolobenzodiazepines (PBDs) are a family of covalent-binding DNA-interactive minor-groove binding agents with a thermodynamic preference for binding to 5'-Pu-G-Pu-3' sequences (Pu = Purine) but a kinetic preference for 5'-Py-G-Py-3' (Py = Pyrimidine). Using HPLC/MS methodology and a range of designed hairpin-forming oligonucleotides, the kinetics of reaction of a C8-bis-pyrrole pyrrolobenzodiazepine (PBD) conjugate (GWL-78, 2) with sixteen isomeric oligonucleotides has been evaluated, each containing a single PBD binding site in one of two locations. The PBD-binding base-pair triplets were designed to include every possible combination of A and T bases adjacent to the covalently-reacting guanine, with the set of hairpins consisting of isomeric pairs containing the same sequence in the hairpin stem but with either hexaethylene glycol (HEG) or TTT loops. The PBD 2 reacted most rapidly with TGT and TGA sequences, with the possibility that adducts might form in both the 3'- and 5'-directions with some sequences according to modelling studies. A faster reaction rate was observed for all hairpins containing the HEG loop except one (Seq 10) when the PBD binding triplets were located either near the loop or adjacent to the 5'-end. Modelling studies have suggested that this difference in reactivity could be due to the structural flexibility of the HEG loop allowing both A-ring-3' and A-ring-5' adducts to form, while a TTT loop should favour only A-ring-5' adducts due to steric considerations. These findings contrast with the results reported by Nguyen and Wilson for the interaction of non-covalent DNA-binding molecules with DNA hairpins, where the loop structure was found to have little effect on interaction in the main stem of the hairpin.
Loops and loop clouds - a numerical approach to the worldline formalism in QED -
Gies, Holger; Gies, Holger; Langfeld, Kurt
2002-01-01
A numerical technique for calculating effective actions of electromagnetic backgrounds is proposed, which is based on the string-inspired worldline formalism. As examples, we consider scalar electrodynamics in three and four dimensions to one-loop order. Beyond the constant-magnetic-field case, we analyze a step-function-like magnetic field exhibiting a nonlocal and nonperturbative phenomenon: ``magnetic-field diffusion''. Finally, generalizations to fermionic loops and systems at finite temperature are discussed.
Energy Technology Data Exchange (ETDEWEB)
S. Pastore,L. Girlanda,R. Schiavilla,M. Viviani,S. Pastore,L. Girlanda,R. Schiavilla,M. Viviani
2011-08-01
The electromagnetic charge operator in a two-nucleon system is derived in chiral effective field theory ($\\chi$EFT) up to order $e\\, Q$ (or N4LO), where $Q$ denotes the low-momentum scale and $e$ is the electric charge. The specific form of the N3LO and N4LO corrections from, respectively, one-pion-exchange and two-pion-exchange depends on the off-the-energy-shell prescriptions adopted for the non-static terms in the corresponding potentials. We show that different prescriptions lead to unitarily equivalent potentials and accompanying charge operators. Thus, provided a consistent set is adopted, predictions for physical observables will remain unaffected by the non-uniqueness associated with these off-the-energy-shell effects.
N'Diaye, Mamadou; Martinache, Frantz; Jovanovic, Nemanja; Lozi, Julien; Guyon, Olivier; Norris, Barnaby; Ceau, Alban; Mary, David
2017-01-01
Island effect (IE) aberrations are induced by differential pistons, tips, and tilts between neighboring pupil segments on ground-based telescopes, which severely limit the observations of circumstellar environments on the recently deployed exoplanet imagers (e.g., VLT/SPHERE, Gemini/GPI, Subaru/SCExAO) during the best observing conditions. Caused by air temperature gradients at the level of the telescope spiders, these aberrations were recently diagnosed with success on VLT/SPHERE, but so far...
Eliseeva, Irina A; Ovchinnikov, Lev P; Lyabin, Dmitry N
2012-12-01
YB-1 is a multifunctional cold shock domain containing protein that is involved virtually in all DNA- and mRNA-dependent cellular events. Its amount is regulated at the level of both transcription and translation. We showed previously that translation of poly A(-) YB-1 mRNA in vitro is selectively controlled by two proteins, YB-1 and PABP, through their specific and competitive binding to a regulatory element (RE) within 3' UTR of this mRNA. Here, we describe effects of these two proteins on translation of poly A(+) as compared with poly A(-) YB-1 mRNA in a rabbit reticulocyte cell-free translation system. We have found that YB-1 inhibits translation of both poly A(+) and poly A(-) YB-1 mRNAs at the same comparatively low YB-1/mRNA ratio. PABP has no positive effect on translation of poly A(+) YB-1 mRNA, although it has a stimulating effect on translation of poly A(-) YB-1 mRNA. A positive PABP effect on translation of poly A(+) YB-1 mRNA arose after removal of a portion of the sequence between RE and the poly(A) tail and disappeared after its replacement by another non-specific sequence of the same length. We also report that the RE fragment forms a complex with the poly(A) fragment in the presence of rabbit reticulocyte lysate (RRL) proteins. For its formation PABP is necessary but not sufficient. These results are in agreement with the proposed model implying formation of a mini-loop at 3' UTR of YB-1 mRNA that includes RE, RRL proteins and the poly(A) tail.
Xu, Shaohua; Wang, Tao; Song, Wen; Jiang, Tao; Zhang, Feng; Yin, Yu; Jiang, Shi-Wen; Wu, Kongming; Yu, Zuoren; Wang, Chenguang; Chen, Ke
2015-08-28
Prostate cancer at advanced stages including metastatic and castration-resistant cancer remains incurable due to the lack of effective therapies. MiR-190a belongs to the small noncoding RNA family and has an important role in breast cancer metastasis. However, it is still unknown whether miR-190a plays a role in prostate cancer development. Herein, we first observed AR/miR-190a/YB-1 forms an auto-regulatory negative feedback loop in prostate cancer: miR-190a expression was down-regulated by AR activation; YB-1 functions are as an AR activator; miR-190a inhibited AR expression and transactivation through direct binding to 3'UTR of YB-1 gene. MiR-190a contributes the human prostate cancer cell growth through AR-dependent signaling. Moreover, we examined the expression of miR-190a and observed a significant decrease in human prostate cancers. Reduced expression of miR-190a was inversely correlated to AR levels of prostate cancer patients, and patients with higher miR-190a expression in their tumor have improved tumor-free survival. Taken together, our findings identified a biochemical and functional link between miR-190a with reduced expression in advanced prostate cancer, YB-1 and AR signaling in prostate cancer.
Energy Technology Data Exchange (ETDEWEB)
Jung, Minhwan; Jeong, Ji-Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-10-15
The objective of this study is to describe the procedure of the self-calibration test for the flowmeters and to analyze the result of the test. In this work, the test procedure of the self-calibration of two flowmeters (FT-101, FT-102) installed in STELLA facility was described and the test result was analyzed. In regard to the long-term SFR development plan, a large-scale sodium thermal-hydraulic test project is being progressed by KAERI. This project is called STELLA (Sodium Integral Effect Test Loop for Safety Simulation and Assessment), and it is proceeding by adopting the QA (Quality Assurance) program. Due to the specificity of an experiment using sodium(Na) categorized as Class 3(pyrophoric material and water-prohibiting substance) by the Safety Control of Dangerous Substances Act, it is necessary to apply QA in consideration of the sodium experiment environment in certain parts. The one of them is about calibration of measuring instrument such as a flowmeter, thermocouple and pressure gauge. It is described in the QAP (Quality Assurance Procedures) of KAERI that calibration work should be conducted in accordance with self-calibration procedures in a special case where conventional calibration is not practicable. The calibration of two flowmeters (FT-101, FT-102) installed in STELLA facility is the typical example. As a result of test, it was confirmed that the flowmeters meet the pass criterion. Therefore, it was concluded that the flowmeters maintain instrument capacity a year ago.
Dehkordi, S. Emad; Schincariol, Robert A.
2013-10-01
Ground-source geothermal systems are drawing increasing attention and popularity due to their efficiency, sustainability and being implementable worldwide. Consequently, design software and regulatory guidelines have been developed. Interaction with the subsurface significantly affects the thermal performance, sustainability, and impacts of such systems. Reviewing the related guidelines and the design software, room for improvement is evident, especially in regards to interaction with groundwater movement. In order to accurately evaluate the thermal effect of system and hydrogeological properties on a borehole heat exchanger, a fully discretized finite-element model is used. Sensitivity of the loop outlet temperatures and heat exchange rates to hydrogeological, system and meteorological factors (i.e. groundwater flux, thermal conductivity and volumetric heat capacity of solids, porosity, thermal dispersivity, grout thermal conductivity, background and inlet temperatures) are analyzed over 6-month and 25-year operation periods. Furthermore, thermal recovery during 25 years after system decommissioning has been modeled. The thermal plume development, transport and dissipation are also assessed. This study shows the importance of subsurface thermal conductivity, groundwater flow (flux > 10-7 m/s), and background and inlet temperature on system performance and impact. It also shows the importance of groundwater flow (flux > 10-8 m/s) on thermal recovery of the ground over other factors.
International Nuclear Information System (INIS)
Boo, Joon Hong
2000-01-01
The thermal performance of a flat evaporator for Capillary Pumped Loop (CPL) applications was investigated. Two to four layers of coarse wire screen wicks were placed onto the heated surface to provide irregular passages for vapor flow. The evaporator and condenser were separated by a distance of 1.2 m and connected by individual liquid and vapor lines. The wall material was copper and the working fluid was ethanol. The experimental facility utilized a combination of capillary and gravitational forces for liquid return, and distribution over the evaporator surface. The tubing used for vapor and liquid lines was 9.35 mm or less in diameter and heat was removed from the condenser by convection of air. A heat flux of up to 4.9x10 4 W/m 2 was applied to a flat evaporator having dimensions of 100 mm by 200 mm, 20 mm thick. The thermal resistance of the system as well as the temperature characteristics of the system was investigated as the evaporator heat flux and the condenser cooling capacity varied. The performance of the evaporator and effect of condenser cooling capacity were analyzed and discussed
On some properties of conjugacy closed loops
International Nuclear Information System (INIS)
Adeniran, John Olusola
2002-07-01
It is shown that central loops are not conjugacy closed loops but instead are loops of units in their loop algebras that are conjugacy closed. It is also shown that certain inner mappings of a conjugacy closed loop are nuclear. Some invariants of left conjugacy closed loops are obtained. (author)
UPTF loop seal tests and their RELAP simulation
International Nuclear Information System (INIS)
Tuomainen, M.; Tuunanen, J.
1997-01-01
In a pressurized water reactor the loop seals have an effect on the natural circulation. If a loop seal is filled with water it can cause a flow stagnation in the loop during two-phase natural circulation. Also the pressure loss over a filled loop seal is high, which lowers the water level in the core. Tests to investigate the loop seal behaviour were performed on a German Upper Plenum Test Facility (UPTF). The purpose of the tests was to study the amount of water in the loop seal under different steam flow rates. The tests were simulated with RELAP5/MOD3.2. With high steam flow rates the code had problems in simulating the amount of the water remaining in the pump elbow, but in general the agreement between the calculated results and the experimental data was good. (orig.)
International Nuclear Information System (INIS)
Furuya, M.; Inada, F.; Yasuo, A.
2001-01-01
Experiments have been conducted to investigate an effect of inlet restriction on the thermal-hydraulic stability. A Test facility used in this study was designed and constructed to have non-dimensional values that are nearly equal to those of natural circulation BWR. Experimental results showed that driving force of the natural circulation at the stability boundary was described as a function of heat flux and inlet subcooling independent of inlet restriction. In order to extend experimental database regarding thermal-hydraulic stability to different inlet restriction, numerical analysis was carried out based on the homogeneous flow model. Stability maps in reference to the core inlet subcooling and heat flux were presented for various inlet restrictions using the above-mentioned function. Instability region during the inlet subcooling shifted to the higher inlet subcooling with increasing inlet restriction and became larger with increasing heat flux. (orig.)
Loop Entropy Assists Tertiary Order: Loopy Stabilization of Stacking Motifs
Directory of Open Access Journals (Sweden)
Daniel P. Aalberts
2011-11-01
Full Text Available The free energy of an RNA fold is a combination of favorable base pairing and stacking interactions competing with entropic costs of forming loops. Here we show how loop entropy, surprisingly, can promote tertiary order. A general formula for the free energy of forming multibranch and other RNA loops is derived with a polymer-physics based theory. We also derive a formula for the free energy of coaxial stacking in the context of a loop. Simulations support the analytic formulas. The effects of stacking of unpaired bases are also studied with simulations.
Design of diamagnetic loop on EAST superconducting tokamak
International Nuclear Information System (INIS)
Xi Weibin; Shen Biao; Qian Jinping; Wu Songtao; Wan Baonan
2007-01-01
The design of EAST diamagnetic measurement system including diamagnetic loop and compensation loop has been given. The advantage of this method is that, the compensation loop is applied for eliminating the change of toroidal flux produced by the toroidal coils and the adjustable structure can be used to decrease the error signals come from the poloidal field. On the other hand, the effect of the material and structure on the diamagnetic loop is detailedly checked during engineering design. Error analysis of the measurement system is given. (authors)
Operation of the hot test loop facilities
International Nuclear Information System (INIS)
Cheong, Moon Ki; Park, Choon Kyeong; Won, Soon Yeon; Yang, Sun Kyu; Cheong, Jang Whan; Cheon, Se Young; Song, Chul Hwa; Jeon, Hyeong Kil; Chang, Suk Kyu; Jeong, Heung Jun; Cho, Young Ro; Kim, Bok Duk; Min, Kyeong Ho
1994-12-01
The objective of this project is to obtain the available experimental data and to develop the measuring techniques through taking full advantage of the facilities. The facilities operated by the thermal hydraulics department have been maintained and repaired in order to carry out the thermal hydraulics tests necessary for providing the available data. The performance tests for double grid type bottom end piece which was improved on the debris filtering effectivity were performed using the PWR-Hot Test Loop. The CANDU-Hot Test Loop was operated to carry out the pressure drop tests and strength tests of fuel. The Cold Test Loop was used to obtain the local velocity data in subchannel within fuel bundle and to understand the characteristic of pressure drop required for improving the nuclear fuel and to develop the advanced measuring techniques. RCS Loop, which is used to measure the CHF, is presently under design and construction. B and C Loop is designed and constructed to assess the automatic depressurization safety system behavior. 4 tabs., 79 figs., 7 refs. (Author) .new
Mass inflation in the loop black hole
International Nuclear Information System (INIS)
Brown, Eric G.; Mann, Robert; Modesto, Leonardo
2011-01-01
In classical general relativity the Cauchy horizon within a two-horizon black hole is unstable via a phenomenon known as mass inflation, in which the mass parameter (and the spacetime curvature) of the black hole diverges at the Cauchy horizon. Here we study this effect for loop black holes - quantum gravitationally corrected black holes from loop quantum gravity - whose construction alleviates the r=0 singularity present in their classical counterparts. We use a simplified model of mass inflation, which makes use of the generalized Dray-'t Hooft relation, to conclude that the Cauchy horizon of loop black holes indeed results in a curvature singularity similar to that found in classical black holes. The Dray-'t Hooft relation is of particular utility in the loop black hole because it does not directly rely upon Einstein's field equations. We elucidate some of the interesting and counterintuitive properties of the loop black hole, and corroborate our results using an alternate model of mass inflation due to Ori.
Logical inference techniques for loop parallelization
Oancea, Cosmin E.
2012-01-01
This paper presents a fully automatic approach to loop parallelization that integrates the use of static and run-time analysis and thus overcomes many known difficulties such as nonlinear and indirect array indexing and complex control flow. Our hybrid analysis framework validates the parallelization transformation by verifying the independence of the loop\\'s memory references. To this end it represents array references using the USR (uniform set representation) language and expresses the independence condition as an equation, S = Ø, where S is a set expression representing array indexes. Using a language instead of an array-abstraction representation for S results in a smaller number of conservative approximations but exhibits a potentially-high runtime cost. To alleviate this cost we introduce a language translation F from the USR set-expression language to an equally rich language of predicates (F(S) ⇒ S = Ø). Loop parallelization is then validated using a novel logic inference algorithm that factorizes the obtained complex predicates (F(S)) into a sequence of sufficient-independence conditions that are evaluated first statically and, when needed, dynamically, in increasing order of their estimated complexities. We evaluate our automated solution on 26 benchmarks from PERFECTCLUB and SPEC suites and show that our approach is effective in parallelizing large, complex loops and obtains much better full program speedups than the Intel and IBM Fortran compilers. Copyright © 2012 ACM.
Analysis of severe accidents on fast reactor test loop
International Nuclear Information System (INIS)
Cenerini, R.; Verzelletti, G.; Curioni, S.
1975-01-01
The Pec reactor is a sodium cooled fast reactor which is being designed for the primary purpose of accomodating closed sodium cooled test loops for the developmental and proof testing of fast reactor fuel assemblies. The test loops are located in the central test region of reactor. The basic function for which the loop is designed is burn-up to failure testing of fuel under advanced performance conditions. It is therefore necessary to design the loop for failure conditions. Basically two types of accidents can occur within the loops: rupture of gas plenum in the fuel pins and coolant starvation. Explosive tests on Pec loop, whose first set is described in this report, are devoted to investigate the effects of an accidental energy release on loop containment. The loop model reproduces in the test section the prototype dimensions in radial scale 1:1. Using a wire explosive charge of 300mm, the height of test section is sufficient for determining the containment capability of the loop that has a nearly constant deformation in a length of. 3-4 time the diameter. The inertial effects of the coolant column are reproduced by two tubes at the extremities of test section, closed with top plugs. Some tests has been performed by wrapping around the test section four layers of steel wire in order to evaluate the influence on the containment of tungsten wire that is foreseen in prototype loop. The influence of the coolant around the loop was evaluated by inserting the model in water. Dummy sub-assemblies was used and explosive substitutes the central rods. Piezoelectric pressure transducers were mounted on the three plugs and radial deformation was measured directly at different height. From experiments performed it resulted the importance of harmonic wires and inertial reaction of external water on loop containment; maximum containable energy is about 50 Cal with E.1 explosive
Covariant diagrams for one-loop matching
Energy Technology Data Exchange (ETDEWEB)
Zhang, Zhengkang [Michigan Univ., Ann Arbor, MI (United States). Michigan Center for Theoretical Physics; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2016-10-15
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gaugecovariant quantities and are thus dubbed ''covariant diagrams.'' The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
On the Loop Current Penetration into the Gulf of Mexico
Weisberg, Robert H.; Liu, Yonggang
2017-12-01
The Gulf of Mexico Loop Current generally intrudes some distance into the Gulf of Mexico before shedding an anticyclonic eddy and retreating back to its more direct entry to exit pathway. The control of this aperiodic process remains only partially known. Here we describe the evolution of the Loop Current throughout the era of satellite altimetry, and offer a mechanistic hypothesis on Loop Current intrusion. As a complement to the known effects of Loop Current forcing on the west Florida shelf circulation, we argue that the west Florida shelf, in turn, impacts the Loop Current evolution. A Self-Organizing Map analysis shows that anomalous northward penetrations of the Loop Current into the Gulf of Mexico occur when the eastern side of Loop Current is positioned west from the southwest corner of the west Florida shelf, whereas the more direct inflow to outflow route occurs when the eastern side of the Loop Current comes in contact with the southwest corner of the west Florida shelf. In essence, we argue that the west Florida shelf anchors the Loop Current in its direct path configuration and that farther northward penetration into the Gulf of Mexico occurs when such anchoring is released. To test of this hypothesis heuristically, we estimate that the dissipation and buoyancy work due to known Loop Current forcing of the west Florida shelf circulation (when in contact with the southwest corner) may exceed the pressure work required for the Loop Current to advance against the ambient Gulf of Mexico fluid.Plain Language SummaryThe Gulf of Mexico Loop Current may intrude far into the Gulf of Mexico or take a more direct entry to exit pathway. Such Loop Current behaviors are described using remote observations by satellites, and a heuristic hypothesis on the control of Loop Current intrusion is presented. We argue that energy dissipation and buoyancy work by the west Florida shelf circulation, when the Loop Current contacts the southwest corner of the west Florida shelf
High temperature storage loop :
Energy Technology Data Exchange (ETDEWEB)
Gill, David Dennis; Kolb, William J.
2013-07-01
A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort
Shortening a loop can increase protein native state entropy.
Gavrilov, Yulian; Dagan, Shlomi; Levy, Yaakov
2015-12-01
Protein loops are essential structural elements that influence not only function but also protein stability and folding rates. It was recently reported that shortening a loop in the AcP protein may increase its native state conformational entropy. This effect on the entropy of the folded state can be much larger than the lower entropic penalty of ordering a shorter loop upon folding, and can therefore result in a more pronounced stabilization than predicted by polymer model for loop closure entropy. In this study, which aims at generalizing the effect of loop length shortening on native state dynamics, we use all-atom molecular dynamics simulations to study how gradual shortening a very long or solvent-exposed loop region in four different proteins can affect their stability. For two proteins, AcP and Ubc7, we show an increase in native state entropy in addition to the known effect of the loop length on the unfolded state entropy. However, for two permutants of SH3 domain, shortening a loop results only with the expected change in the entropy of the unfolded state, which nicely reproduces the observed experimental stabilization. Here, we show that an increase in the native state entropy following loop shortening is not unique to the AcP protein, yet nor is it a general rule that applies to all proteins following the truncation of any loop. This modification of the loop length on the folded state and on the unfolded state may result with a greater effect on protein stability. © 2015 Wiley Periodicals, Inc.
G(2) Hitchin functionals at one loop
de Boer, J.; de Medeiros, P.; El-Showk, S.; Sinkovics, A.
2008-01-01
We consider the quantization of the effective target space description of topological M-theory in terms of the Hitchin functional whose critical points describe seven manifolds with a G(2) structure. The one-loop partition function for this theory is calculated and an extended version of it, that is
Loop Corrections in Very Special Relativity Standard Model
Alfaro, Jorge
2018-01-01
In this talk we want to study one-loop corrections in VSRSM. In particular, we use the new Sim(2)-invariant dimensional regularization to compute one-loop corrections to the Effective Action in the subsector of the VSRSM that describe the interaction of photons with charged leptons. New stringent bounds for the masses of ve and vµ are obtained.
Modeling of compact loop antennas
International Nuclear Information System (INIS)
Baity, F.W.
1987-01-01
A general compact loop antenna model which treats all elements of the antenna as lossy transmission lines has been developed. In addition to capacitively-tuned resonant double loop (RDL) antennas the model treats stub-tuned resonant double loop antennas. Calculations using the model have been compared with measurements on full-scale mockups of resonant double loop antennas for ATF and TFTR in order to refine the transmission line parameters. Results from the model are presented for RDL antenna designs for ATF, TFTR, Tore Supra, and for the Compact Ignition Tokamak
[Morbidity of lateral loop ileostomy].
François, Y; Griot, J B; Molter, A; Gilly, F N; Carry, P Y; Sayag, A; Vignal, J
1996-01-01
The aim of this retrospective study was to assess the morbidity of twisted loop ileostomy (TLI). Between 1985 and 1994, 83 TLI were performed in 79 patients. Before TLI closure, 13 patients (16%) presented complications, requiring surgery in 5 cases. Small bowel obstruction (7 cases: 8%) and high stoma output (4 cases: 5%) were the commonest complications. After stoma closure (performed in 76 cases), 8 patients (10.5%) presented complications, requiring surgery in 3 cases. The most commonest complication was enteric fistula (4 cases: 5.3%) requiring reoperation in 2 cases. This procedure adds a separate set of postoperative complications, which tend to be minor in nature without any permanent sequelae and which can be minimized by a meticulous surgical technique. This technique remains a safe and effective procedure for fecal diversion.
Wang, Lingxin; Nomura, Yoshiko; Du, Yuzhe; Liu, Nannan; Zhorov, Boris S.
2015-01-01
Activation and inactivation of voltage-gated sodium channels are critical for proper electrical signaling in excitable cells. Pyrethroid insecticides promote activation and inhibit inactivation of sodium channels, resulting in prolonged opening of sodium channels. They preferably bind to the open state of the sodium channel by interacting with two distinct receptor sites, pyrethroid receptor sites PyR1 and PyR2, formed by the interfaces of domains II/III and I/II, respectively. Specific mutations in PyR1 or PyR2 confer pyrethroid resistance in various arthropod pests and disease vectors. Recently, a unique mutation, N1575Y, in the cytoplasmic loop linking domains III and IV (LIII/IV) was found to coexist with a PyR2 mutation, L1014F in IIS6, in pyrethroid-resistant populations of Anopheles gambiae. To examine the role of this mutation in pyrethroid resistance, N1575Y alone or N1575Y + L1014F were introduced into an Aedes aegypti sodium channel, AaNav1-1, and the mutants were functionally examined in Xenopus oocytes. N1575Y did not alter AaNav1-1 sensitivity to pyrethroids. However, the N1575Y + L1014F double mutant was more resistant to pyrethroids than the L1014F mutant channel. Further mutational analysis showed that N1575Y could also synergize the effect of L1014S/W, but not L1014G or other pyrethroid-resistant mutations in IS6 or IIS6. Computer modeling predicts that N1575Y allosterically alters PyR2 via a small shift of IIS6. Our findings provide the molecular basis for the coexistence of N1575Y with L1014F in pyrethroid resistance, and suggest an allosteric interaction between IIS6 and LIII/IV in the sodium channel. PMID:25523031
International Nuclear Information System (INIS)
Gzyl, Jaroslaw; Bolesta, Elizabeth; Wierzbicki, Andrew; Kmieciak, Dariusz; Naito, Toshio; Honda, Mitsuo; Komuro, Katsutoshi; Kaneko, Yutaro; Kozbor, Danuta
2004-01-01
Induction of cross-reactive cellular and humoral responses to the HIV-1 envelope (env) glycoprotein was examined after DNA immunization of BALB/c mice with gp140 89.6 -derived constructs exhibiting partial or complete deletions of the V1, V2, and V3 domains. It was demonstrated that specific modification of the V3 loop (mV3) in combination with the V2-modified (mV2) or V1/V2-deleted (ΔV1/V2) region elicited increased levels of cross-reactive CD8 + T cell responses. Mice immunized with the mV2/mV3 or ΔV1/V2/mV3 gp140 89.6 plasmid DNA were greater than 50-fold more resistant to challenge with recombinant vaccinia virus (rVV) expressing heterologous env gene products than animals immunized with the wild-type (WT) counterpart. Sera from mV2/mV3- and ΔV1/V2/mV3-immunized mice exhibited the highest cross-neutralizing activity and displayed intermediate antibody avidity values which were further enhanced by challenge with rVV expressing the homologous gp160 glycoprotein. In contrast, complete deletion of the variable regions had little or no effect on the cross-reactive antibody responses. The results of these experiments indicate that the breadth of antibody responses to the HIV-1 env glycoprotein may not be increased by removal of the variable domains. Instead, partial deletions within these regions may redirect specific responses toward conserved epitopes and facilitate approaches for boosting cross-reactive cellular and antibody responses to the env glycoprotein
Kang, Woo Dae; Choi, Ho Sun; Kim, Seok Mo
2013-08-01
This study was conducted to determine whether vaccination with the quadrivalent human papillomavirus (HPV) vaccine after loop electrosurgical excision procedure (LEEP) for high-grade cervical intraepithelial neoplasia (CIN2-3) is effective in preventing recurrence of CIN2-3. Between August 2007 and July 2010, 737 patients aged 20-45 years who were diagnosed with CIN2-3 were treated by LEEP and followed. Three hundred and sixty patients were vaccinated with the quadrivalent HPV vaccine after LEEP (vaccination group), and 377 patients were followed without vaccination (non-vaccination group). The vaccination group received the first dose at 1 week after LEEP and the remaining two doses two and six months later. Post-LEEP follow-up was performed at 3, 6, 9, 12, 18, and 24 months during the first 2 years and yearly thereafter. Irrespective of causal HPV type, 36 (4.9%) patients developed recurrence. In the vaccination group (360 patients), 9 patients (2.5%) developed recurrence, whereas 27 patients (7.2%) in the non-vaccination group (377 patients) developed recurrence. In patients infected with HPV of 16 and/or 18 type, 5 patients (2.5%) in the vaccination group (197 patients) and 18 patients (8.5%) in the non-vaccination group (211 patients) developed recurrent disease related to vaccine HPV types (HPV 16 or 18 types) after LEEP (Pvaccination after LEEP was an independent risk factor for recurrent CIN2-3 (HR=2.840; 95% confidence interval, 1.335-6.042; PVaccination with the quadrivalent HPV vaccine after treatment may be considered in preventing recurrence of CIN2-3. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.
Freeman, Kendra D; Barrett, Jennifer G; Youngstrom, Daniel W; White, Nathaniel A
2015-08-01
The 6-strand Savage (SSS) tenorrhaphy pattern is biomechanically superior to the commonly employed 3-loop pulley (3LP); however, its effects on intrinsic tendon vasculature remain unknown. The objective of this study was to compare perfusion of intrinsic vasculature of the equine superficial digital flexor tendon (SDFT) after 3LP and SSS tenorrhaphies. We hypothesized that the SSS technique would significantly decrease vascular perfusion compared to the 3LP technique. Ex vivo, randomized, paired design. Horses (n = 9) METHODS: Under general anesthesia, 9 pairs of forelimb SDFT were transected. Two tendons served as baseline control, the remainder had either SSS or 3LP tenorrhaphy performed. Horses were heparinized, euthanatized, and forelimbs perfused with barium sulfate solution were then fixed with formalin under tension. Tendons were transected every 5 mm and microangiographic images obtained. Microvascular analysis of sections proximal to, throughout, and distal to the tenorrhaphy was completed using a custom macro. Differences in vascular count were assessed using MANOVA. A significant reduction in the number of perfused vessels was seen for SSS compared with 3LP at 2 locations within the tenorrhaphy (P = .039 and P = .009). The SSS technique took on average 4.7 ± 0.9 times longer to place. The SSS technique causes an acute reduction in tendon perfusion compared to the 3LP, which may limit its clinical use. Further research is required to elucidate the clinical significance of this difference. © Copyright 2015 by The American College of Veterinary Surgeons.
International Nuclear Information System (INIS)
Chesi, Stefano; Jaffe, Arthur; Loss, Daniel; Pedrocchi, Fabio L.
2013-01-01
We investigate the role that vortex loops play in characterizing eigenstates of interacting Majoranas. We give some general results and then focus on ladder Hamiltonian examples as a test of further ideas. Two methods yield exact results: (i) A mapping of certain spin Hamiltonians to quartic interactions of Majoranas shows that the spectra of these two examples coincide. (ii) In cases with reflection-symmetric Hamiltonians, we use reflection positivity for Majoranas to characterize vortices in the ground states. Two additional methods suggest wider applicability of these results: (iii) Numerical evidence suggests similar behavior for certain systems without reflection symmetry. (iv) A perturbative analysis also suggests similar behavior without the assumption of reflection symmetry
International Nuclear Information System (INIS)
Pei, L.; Klebaner, A.; Theilacker, J.; Soyars, W.; Martinez, A.; Bossert, R.; DeGraff, B.; Darve, C.
2011-01-01
The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters oscillation.
International Nuclear Information System (INIS)
Ladd-Lively, Jennifer L
2008-01-01
The objectives of the work discussed in this report were to: (1) develop a flow loop that would simulate the purified uranium-bearing aqueous stream exiting the solvent extraction process in a natural uranium conversion plant (NUCP); (2) develop a test plan that would simulate normal operation and disturbances that could be anticipated in an NUCP; (3) use the flow loop to test commercially available flowmeters for use as safeguards monitors; and (4) recommend a flowmeter for production-scale testing at an NUCP. There has been interest in safeguarding conversion plants because the intermediate products [uranium dioxide (UO 2 ), uranium tetrafluoride (UF 4 ), and uranium hexafluoride (UF 6 )] are all suitable uranium feedstocks for producing special nuclear materials. Furthermore, if safeguards are not applied virtually any nuclear weapons program can obtain these feedstocks without detection by the International Atomic Energy Agency (IAEA). Historically, IAEA had not implemented safeguards until the purified UF 6 product was declared as feedstock for enrichment plants. H. A. Elayat et al. provide a basic definition of a safeguards system: 'The function of a safeguards system on a chemical conversion plant is in general terms to verify that no useful nuclear material is being diverted to use in a nuclear weapons program'. The IAEA now considers all highly purified uranium compounds as candidates for safeguarding. DOE is currently interested in 'developing instruments, tools, strategies, and methods that could be of use to the IAEA in the application of safeguards' for materials found in the front end of the nuclear fuel cycle-prior to the production of the uranium hexafluoride or oxides that have been the traditional starting point for IAEA safeguards. Several national laboratories, including Oak Ridge, Los Alamos, Lawrence Livermore, and Brookhaven, have been involved in developing tools or techniques for safeguarding conversion plants. This study was sponsored by
Miura, Masanobu; Sugimura, Koichiro; Sakata, Yasuhiko; Miyata, Satoshi; Tadaki, Soichiro; Yamauchi, Takeshi; Onose, Takeo; Tsuji, Kanako; Abe, Ruri; Oikawa, Takuya; Kasahara, Shintaro; Nochioka, Kotaro; Takahashi, Jun; Shimokawa, Hiroaki
2016-05-25
It remains to be elucidated whether addition of renin-angiotensin-aldosterone system (RAAS) inhibitors and/or β-blockers to loop diuretics has a beneficial prognostic impact on chronic heart failure (CHF) patients. From the Chronic Heart failure Analysis and Registry in the Tohoku district 2 (CHART-2) Study (n=10,219), we enrolled 4,134 consecutive patients with symptomatic stage C/D CHF (mean age, 69.3 years, 67.7% male). We constructed Cox models for composite of death, myocardial infarction, stroke and HF admission. On multivariate inverse probability of treatment weighted (IPTW) Cox modeling, loop diuretics use was associated with worse prognosis with hazard ratio (HR) 1.28 (Pdiuretics were associated with worse prognosis with HR 1.32 and 1.56, respectively (both Pdiuretics. Chronic use of loop diuretics is significantly associated with worse prognosis in CHF patients in a dose-dependent manner, whereas the triple combination of RAAS inhibitor(s), MRA, and β-blocker(s) is associated with better prognosis when combined with low-dose loop diuretics. (Circ J 2016; 80: 1396-1403).
Loop-loop interactions govern multiple steps in indole-3-glycerol phosphate synthase catalysis.
Zaccardi, Margot J; O'Rourke, Kathleen F; Yezdimer, Eric M; Loggia, Laura J; Woldt, Svenja; Boehr, David D
2014-03-01
Substrate binding, product release, and likely chemical catalysis in the tryptophan biosynthetic enzyme indole-3-glycerol phosphate synthase (IGPS) are dependent on the structural dynamics of the β1α1 active-site loop. Statistical coupling analysis and molecular dynamic simulations had previously indicated that covarying residues in the β1α1 and β2α2 loops, corresponding to Arg54 and Asn90, respectively, in the Sulfolobus sulfataricus enzyme (ssIGPS), are likely important for coordinating functional motions of these loops. To test this hypothesis, we characterized site mutants at these positions for changes in catalytic function, protein stability and structural dynamics for the thermophilic ssIGPS enzyme. Although there were only modest changes in the overall steady-state kinetic parameters, solvent viscosity and solvent deuterium kinetic isotope effects indicated that these amino acid substitutions change the identity of the rate-determining step across multiple temperatures. Surprisingly, the N90A substitution had a dramatic effect on the general acid/base catalysis of the dehydration step, as indicated by the loss of the descending limb in the pH rate profile, which we had previously assigned to Lys53 on the β1α1 loop. These changes in enzyme function are accompanied with a quenching of ps-ns and µs-ms timescale motions in the β1α1 loop as measured by nuclear magnetic resonance studies. Altogether, our studies provide structural, dynamic and functional rationales for the coevolution of residues on the β1α1 and β2α2 loops, and highlight the multiple roles that the β1α1 loop plays in IGPS catalysis. Thus, substitution of covarying residues in the active-site β1α1 and β2α2 loops of indole-3-glycerol phosphate synthase results in functional, structural, and dynamic changes, highlighting the multiple roles that the β1α1 loop plays in enzyme catalysis and the importance of regulating the structural dynamics of this loop through noncovalent
RCD+: Fast loop modeling server.
López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo
2016-07-08
Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.
Stepping out of homogeneity in loop quantum cosmology
International Nuclear Information System (INIS)
Rovelli, Carlo; Vidotto, Francesca
2008-01-01
We explore the extension of quantum cosmology outside the homogeneous approximation using the formalism of loop quantum gravity. We introduce a model where some of the inhomogeneous degrees of freedom are present, providing a tool for describing general fluctuations of quantum geometry near the initial singularity. We show that the dynamical structure of the model reduces to that of loop quantum cosmology in the Born-Oppenheimer approximation. This result corroborates the assumptions that ground loop cosmology sheds some light on the physical and mathematical relation between loop cosmology and full loop quantum gravity, and on the nature of the cosmological approximation. Finally, we show that the non-graph-changing Hamiltonian constraint considered in the context of algebraic quantum gravity provides a viable effective dynamics within this approximation
Xenon oscillation tests in four-loop PWR cores
International Nuclear Information System (INIS)
Aoki, Norihiko; Osaka, Kenichi; Shimada, Shoichiro; Tochihara, Hiroshi; Machii, Seigo
1980-01-01
The Kansai Electric Power Co.'s OHI Unit 1 and 2 are the first 4-loop PWRs in Japan which use 17 x 17 fuel assemblies and have essentially the same plant parameters. A 4-loop core has larger core radius and higher power density than those of 2- or 3-loop cores, and is less stable for Xe oscillation. It is therefore important to confirm that Xe oscillations in radial direction are sufficiently stable in a 4-loop core. Radial and axial Xe oscillation tests were performed during the startup physics tests of OHI Unit 1 and 2; Xe oscillation was induced by perturbation of control rods and the Xe effect on power distribution observed periodically. The test results show that the transverse Xe oscillation in the 4-loop core is sufficiently stable and that the agreement between the measurement and the calculated prediction is good. (author)
Semiclassical analysis of loop quantum gravity
International Nuclear Information System (INIS)
Conrady, F.
2005-01-01
In this Ph.D. thesis, we explore and develop new methods that should help in determining an effective semiclassical description of canonical loop quantum gravity and spin foam gravity. A brief introduction to loop quantum gravity is followed by three research papers that present the results of the Ph.D. project. In the first article, we deal with the problem of time and a new proposal for implementing proper time as boundary conditions in a sum over histories: we investigate a concrete realization of this formalism for free scalar field theory. In the second article, we translate semiclassical states of linearized gravity into states of loop quantum gravity. The properties of the latter indicate how semiclassicality manifests itself in the loop framework, and how this may be exploited for doing semiclassical expansions. In the third part, we propose a new formulation of spin foam models that is fully triangulation- and background-independent: by means of a symmetry condition, we identify spin foam models whose triangulation-dependence can be naturally removed. (orig.)
Semiclassical analysis of loop quantum gravity
Energy Technology Data Exchange (ETDEWEB)
Conrady, F.
2005-10-17
In this Ph.D. thesis, we explore and develop new methods that should help in determining an effective semiclassical description of canonical loop quantum gravity and spin foam gravity. A brief introduction to loop quantum gravity is followed by three research papers that present the results of the Ph.D. project. In the first article, we deal with the problem of time and a new proposal for implementing proper time as boundary conditions in a sum over histories: we investigate a concrete realization of this formalism for free scalar field theory. In the second article, we translate semiclassical states of linearized gravity into states of loop quantum gravity. The properties of the latter indicate how semiclassicality manifests itself in the loop framework, and how this may be exploited for doing semiclassical expansions. In the third part, we propose a new formulation of spin foam models that is fully triangulation- and background-independent: by means of a symmetry condition, we identify spin foam models whose triangulation-dependence can be naturally removed. (orig.)
Autosomal mutations affecting Y chromosome loops in Drosophila melanogaster
Directory of Open Access Journals (Sweden)
Petrucci Romano
2008-04-01
Full Text Available Abstract Background The Y chromosome of Drosophila melanogaster harbors several genes required for male fertility. The genes for these fertility factors are very large in size and contain conspicuous amounts of repetitive DNA and transposons. Three of these loci (ks-1, kl-3 and kl-5 have the ability to develop giant lampbrush-like loops in primary spermatocytes, a cytological manifestation of their active state in these cells. Y-loops bind a number of non-Y encoded proteins, but the mechanisms regulating their development and their specific functions are still to be elucidated. Results Here we report the results of a screen of 726 male sterile lines to identify novel autosomal genes controlling Y-loop function. We analyzed mutant testis preparations both in vivo and by immunofluorescence using antibodies directed against Y-loop-associated proteins. This screen enabled us to isolate 17 mutations at 15 loci whose wild-type function is required for proper Y-loop morphogenesis. Six of these loci are likely to specifically control loop development, while the others display pleiotropic effects on both loops and meiotic processes such as spermiogenesis, sperm development and maturation. We also determined the map position of the mutations affecting exclusively Y-loop morphology. Conclusion Our cytological screening permitted us to identify novel genetic functions required for male spermatogenesis, some of which show pleiotropic effects. Analysis of these mutations also shows that loop development can be uncoupled from meiosis progression. These data represent a useful framework for the characterization of Y-loop development at a molecular level and for the study of the genetic control of heterochromatin.
Directory of Open Access Journals (Sweden)
Giorgio Zamboni
2017-01-01
Full Text Available Reduction of NOX emissions and fuel consumption are the main topics in engine development, forcing the adoption of complex techniques and components, whose interactions have to be clearly understood for proper and reliable operations and management of the whole system. The investigation presented in this paper aimed at the development of integrated control strategies of turbocharging, high pressure (HP and low pressure (LP exhaust gas recirculation (EGR systems for better NOX emissions and fuel consumption, while analyzing their reciprocal influence and the resulting variations of engine quantities. The study was based on an extended experimental program in three part load engine operating conditions. In the paper a comparison of the behavior of the main engine sub-systems (intake and exhaust circuits, turbocharger turbine and compressor, HP and LP EGR loops in a wide range of operating modes is presented and discussed, considering open and closed loop approaches for variable nozzle turbine (VNT control, and showing how these affect engine performance and emissions. The potential of significant decrease in NOX emissions through the integration of HP and LP EGR was confirmed, while a proper VNT management allowed for improved fuel consumption level, if an open loop control scheme is followed. At higher engine speed and load, further actions have to be applied to compensate for observed soot emissions increase.
BMN correlators by loop equations
International Nuclear Information System (INIS)
Eynard, Bertrand; Kristjansen, Charlotte
2002-01-01
In the BMN approach to N=4 SYM a large class of correlators of interest are expressible in terms of expectation values of traces of words in a zero-dimensional gaussian complex matrix model. We develop a loop-equation based, analytic strategy for evaluating such expectation values to any order in the genus expansion. We reproduce the expectation values which were needed for the calculation of the one-loop, genus one correction to the anomalous dimension of BMN-operators and which were earlier obtained by combinatorial means. Furthermore, we present the expectation values needed for the calculation of the one-loop, genus two correction. (author)
International Nuclear Information System (INIS)
Kalibjian, R.; Chong, Y.P.; Prono, D.S.; Cavagnolo, H.R.
1984-06-01
The ATA provides an electron beam pulse of 70-ns duration at a 1-Hz rate. Our present optical diagnostics technique involve the imaging of the visible light generated by the beam incident onto the plant of a thin sheet of material. It has already been demonstrated that the light generated has a sufficiently fast temporal reponse in performing beam diagnostics. Notwithstanding possible beam emittance degradation due to scattering in the thin sheet, the observation of beam spatial profiles with relatively high efficiencies has provided data complementary to that obtained from beam wall current monitors and from various x-ray probes and other electrical probes. The optical image sensor consists of a gated, intensified television system. The gate pulse of the image intensifier can be appropriately delayed to give frames that are time-positioned from the head to the tail of the beam with a minimum gate time of 5-ns. The spatial correlation of the time frames from pulse to pulse is very good for a stable electron beam; however, when instabilities do occur, it is difficult to properly assess the spatial composition of the head and the tail of the beam on a pulse-to-pulse basis. Multiple gating within a pulse duration becomes desirable but cannot be performed because the recycle time (20-ms) of the TV system is much longer than the beam pulse. For this reason we have developed an optical-loop framing technique that will allow the recording of two frames within one pulse duration with our present gated/intensified TV system
Palkowski, Marek; Bielecki, Wlodzimierz
2017-06-02
RNA secondary structure prediction is a compute intensive task that lies at the core of several search algorithms in bioinformatics. Fortunately, the RNA folding approaches, such as the Nussinov base pair maximization, involve mathematical operations over affine control loops whose iteration space can be represented by the polyhedral model. Polyhedral compilation techniques have proven to be a powerful tool for optimization of dense array codes. However, classical affine loop nest transformations used with these techniques do not optimize effectively codes of dynamic programming of RNA structure predictions. The purpose of this paper is to present a novel approach allowing for generation of a parallel tiled Nussinov RNA loop nest exposing significantly higher performance than that of known related code. This effect is achieved due to improving code locality and calculation parallelization. In order to improve code locality, we apply our previously published technique of automatic loop nest tiling to all the three loops of the Nussinov loop nest. This approach first forms original rectangular 3D tiles and then corrects them to establish their validity by means of applying the transitive closure of a dependence graph. To produce parallel code, we apply the loop skewing technique to a tiled Nussinov loop nest. The technique is implemented as a part of the publicly available polyhedral source-to-source TRACO compiler. Generated code was run on modern Intel multi-core processors and coprocessors. We present the speed-up factor of generated Nussinov RNA parallel code and demonstrate that it is considerably faster than related codes in which only the two outer loops of the Nussinov loop nest are tiled.
One-loop background calculations in the general field theory
Pronin, P.; Stepanyantz, K.
1996-01-01
We present master formulas for the divergent part of the one-loop effective action for a minimal operator of any order in the 4-dimensional curved space and for an arbitrary nonminimal operator in the flat space.
Loop quantum cosmology: Recent progress
Indian Academy of Sciences (India)
. These techniques and their implications can be illustrated and tested in simple sit- uations by introducing symmetries, which is the origin of loop quantum cosmology. The symmetry reduction can be done in such a way that the characteristic ...
Dynamical behaviour in coronal loops
Haisch, Bernhard M.
1986-01-01
Rapid variability has been found in two active region coronal loops observed by the X-ray Polychromator (XRP) and the Hard X-ray Imaging Spectrometer (HXIS) onboard the Solar Maximum Mission (SMM). There appear to be surprisingly few observations of the short-time scale behavior of hot loops, and the evidence presented herein lends support to the hypothesis that coronal heating may be impulsive and driven by flaring.
Closed Loop Fluid Delivery System
2014-02-28
loop fluid delivery system (CLFDS) will integrate a vital signs monitor ( VSM ) and high speed infusion pump (Pump) to respond quickly to drops in...Interface (GUI) shows VSM data, allows the user to select from several injury types (head, uncontrolled hemorrhage, controlled hemorrhage, and three total...the bedrock for future Closed Loop Fluid System Pre-Market Approval application(s) to FDA. 6. Major Issues Clinical study testing revealed a
Quantum hysteresis loops in microscopic system: The loop area as a ...
Indian Academy of Sciences (India)
Abstract. The area enclosed by hysteresis loops in a periodically forced bistable microscopic sys- tem at zero-temperature is examined by using the time dependent Hellmann–Feynman theorem and the Fourier grid Hamiltonian recipe for solving time-dependent Schr¨odinger equation. Effects of non-zero temperatures are ...
Directory of Open Access Journals (Sweden)
Mehdi Dehjourian
2016-08-01
Full Text Available The containment response during the first 24 hours of a low-pressure severe accident scenario in a nuclear power plant with a two-loop Westinghouse-type pressurized water reactor was simulated with the CONTAIN 2.0 computer code. The accident considered in this study is a large-break loss-of-coolant accident, which is not successfully mitigated by the action of safety systems. The analysis includes pressure and temperature responses, as well as investigation into the influence of spray on the retention of fission products and the prevention of hydrogen combustion in the containment.
International Nuclear Information System (INIS)
Castiglia, F.; Oliveri, E.; Taibi, S.; Vella, G.
1992-01-01
In order to improve the safety features of a 3-loop pressurized water nuclear reactor we propose a slight design variant consisting in the introduction of a bypass hole in the divider plate of the coolant chambers of the steam generators. The aim is to reduce both the extent and the duration of the core exposure and thus the maximum value of the peak cladding temperature, in case of a hypothetical cold leg small break loss of coolant accident. The proposal, as attested by a preliminary RELAP5/MOD3 analysis, seems to deserve some attention. (6 figures) (Author)
DEFF Research Database (Denmark)
Jonassen, Thomas; Christensen, Sten; Marcussen, Niels
2006-01-01
in renal plasma flow, glomerular filtration rate, or circulating levels of aldosterone and vasopressin. Renal clearance studies revealed that IROA normalized the increased natriuretic efficacy of furosemide found in CBL rats. Furthermore, IROA protected against the development of hypertrophy of the inner...... stripe of the outer medulla and thereby the increased the volume of thick ascending limb of Henle's loop (TAL) epithelium found in CBL rats. Finally, Western blot analyses of outer medullary homogenates showed increased abundance of the furosemide-sensitive Na-K-2Cl (NKCC2) cotransporter. IROA did...
Point-defect migration into an infinitesimal dislocation loop
International Nuclear Information System (INIS)
Woo, C.H.
1981-11-01
Point-defect migration into an infinitesimal dislocation loop in an isotropic linear elastic medium is described. Particular care has been taken to include the effects of the saddle-point shape anisotropy of the point defect. Expressions for the reaction radii and the bias are derived, both in the presence and absence of an external applied stress. These are found to depend on intrinsic parameters, such as the loop strength, the loop nature (vacancy or interstitial), the relaxation volume, the saddle-point shape, and extrinsic parameters, such as the magnitude and direction of the external stress, and the temperature. The implications of the results are discussed
The gluon beam function at two loops
Gaunt, Jonathan R.; Stahlhofen, Maximilian; Tackmann, Frank J.
2014-08-01
The virtuality-dependent beam function is a universal ingredient in the resummation for observables probing the virtuality of incoming partons, including N -jettiness and beam thrust. We compute the gluon beam function at two-loop order. Together with our previous results for the two-loop quark beam function, this completes the full set of virtuality-dependent beam functions at next-to-next-to-leading order (NNLO). Our results are required to account for all collinear initial-state radiation effects on the N -jettiness event shape through N3LL order. We present numerical results for both the quark and gluon beam functions up to NNLO and N3LL order. Numerically, the NNLO matching corrections are important. They reduce the residual matching scale dependence in the resummed beam function by about a factor of two.
The gluon beam function at two loops
Energy Technology Data Exchange (ETDEWEB)
Gaunt, Jonathan R.; Stahlhofen, Maximilian; Tackmann, Frank J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2014-05-15
The virtuality-dependent beam function is a universal ingredient in the resummation for observables probing the virtuality of incoming partons, including N-jettiness and beam thrust. We compute the gluon beam function at two-loop order. Together with our previous results for the two-loop quark beam function, this completes the full set of virtuality-dependent beam functions at next-to-next-to-leading order (NNLO). Our results are required to account for all collinear ISR effects to the N-jettiness event shape through N{sup 3}LL order. We present numerical results for both the quark and gluon beam functions up to NNLO and N{sup 3}LL order. Numerically, the NNLO matching corrections are important. They reduce the residual matching scale dependence in the resummed beam function by about a factor of two.
Temperature measurement of accelerator cell solenoid loop
International Nuclear Information System (INIS)
Mu Fan; Dong Pan; Dai Zhiyong
2010-01-01
This paper presents the research on temperature measurement of solenoid loop. The measuring temperature fiber is layered in solenoid loop for the accelerator cell. When the solenoid loop is supplied with high current form a constant current source, its temperature increases rapidly. The temperature fiber can measure the temperature of the solenoid loop and get temperature measurement rule. Experiment and simulation show temperature of interior solenoid loop the highest and it decreases from the interior to the exterior of solenoid loop. To control temperature of solenoid loop under 60 degree C, simulation displays load interval of constant current source with 80 A current should be at least is 17.5 minutes. (authors)
On the one-loop calculations with Reggeized quarks
Nefedov, Maxim; Saleev, Vladimir
2017-12-01
The technique of one-loop calculations for the processes involving Reggeized quarks is described in the framework of gauge invariant effective field theory for the Multi-Regge limit of QCD, which has been introduced by Lipatov and Vyazovsky. The rapidity divergences, associated with the terms enhanced by log(s), appear in the loop corrections in this formalism. The covariant procedure of regularization of rapidity divergences, preserving the gauge invariance of effective action is described. As an example application, the one-loop correction to the propagator of Reggeized quark and γQq-scattering vertex are computed. Obtained results are used to construct the Regge limit of one-loop γγ → qq¯ amplitude. The cancellation of rapidity divergences and consistency of the EFT prediction with the full QCD result is demonstrated. The rapidity renormalization group within the EFT is discussed.
Accumulation of dislocation loops in the α phase of Zr Excel alloy under heavy ion irradiation
Yu, Hongbing; Yao, Zhongwen; Idrees, Yasir; Zhang, He K.; Kirk, Mark A.; Daymond, Mark R.
2017-08-01
In-situ heavy ion irradiations were performed on the high Sn content Zr alloy 'Excel', measuring type dislocation loop accumulation up to irradiation damage doses of 10 dpa at a range of temperatures. The high content of Sn, which diffuses slowly, and the thin foil geometry of the sample provide a unique opportunity to study an extreme case where displacement cascades dominate the loop formation and evolution. The dynamic observation of dislocation loop evolution under irradiation at 200 °C reveals that type dislocation loops can form at very low dose (0.0025 dpa). The size of the dislocation loops increases slightly with irradiation damage dose. The mechanism controlling loop growth in this study is different from that in neutron irradiation; in this study, larger dislocation loops can condense directly from the interaction of displacement cascades and the high concentration of point defects in the matrix. The size of the dislocation loop is dependent on the point defect concentration in the matrix. A negative correlation between the irradiation temperature and the dislocation loop size was observed. A comparison between cascade dominated loop evolution (this study), diffusion dominated loop evolution (electron irradiation) and neutron irradiation suggests that heavy ion irradiation alone may not be enough to accurately reproduce neutron irradiation induced loop structures. An alternative method is proposed in this paper. The effects of Sn on the displacement cascades, defect yield, and the diffusion behavior of point defects are established.
Innovative hybrid pile oscillator technique in the Minerve reactor: open loop vs. closed loop
Geslot, Benoit; Gruel, Adrien; Bréaud, Stéphane; Leconte, Pierre; Blaise, Patrick
2018-01-01
Pile oscillator techniques are powerful methods to measure small reactivity worth of isotopes of interest for nuclear data improvement. This kind of experiments has long been implemented in the Mineve experimental reactor, operated by CEA Cadarache. A hybrid technique, mixing reactivity worth estimation and measurement of small changes around test samples is presented here. It was made possible after the development of high sensitivity miniature fission chambers introduced next to the irradiation channel. A test campaign, called MAESTRO-SL, took place in 2015. Its objective was to assess the feasibility of the hybrid method and investigate the possibility to separate mixed neutron effects, such as fission/capture or scattering/capture. Experimental results are presented and discussed in this paper, which focus on comparing two measurements setups, one using a power control system (closed loop) and another one where the power is free to drift (open loop). First, it is demonstrated that open loop is equivalent to closed loop. Uncertainty management and methods reproducibility are discussed. Second, results show that measuring the flux depression around oscillated samples provides valuable information regarding partial neutron cross sections. The technique is found to be very sensitive to the capture cross section at the expense of scattering, making it very useful to measure small capture effects of highly scattering samples.
Innovative hybrid pile oscillator technique in the Minerve reactor: open loop vs. closed loop
Directory of Open Access Journals (Sweden)
Geslot Benoit
2018-01-01
Full Text Available Pile oscillator techniques are powerful methods to measure small reactivity worth of isotopes of interest for nuclear data improvement. This kind of experiments has long been implemented in the Mineve experimental reactor, operated by CEA Cadarache. A hybrid technique, mixing reactivity worth estimation and measurement of small changes around test samples is presented here. It was made possible after the development of high sensitivity miniature fission chambers introduced next to the irradiation channel. A test campaign, called MAESTRO-SL, took place in 2015. Its objective was to assess the feasibility of the hybrid method and investigate the possibility to separate mixed neutron effects, such as fission/capture or scattering/capture. Experimental results are presented and discussed in this paper, which focus on comparing two measurements setups, one using a power control system (closed loop and another one where the power is free to drift (open loop. First, it is demonstrated that open loop is equivalent to closed loop. Uncertainty management and methods reproducibility are discussed. Second, results show that measuring the flux depression around oscillated samples provides valuable information regarding partial neutron cross sections. The technique is found to be very sensitive to the capture cross section at the expense of scattering, making it very useful to measure small capture effects of highly scattering samples.
Tritium Management Loop Design Status
Energy Technology Data Exchange (ETDEWEB)
Rader, Jordan D. [ORNL; Felde, David K. [ORNL; McFarlane, Joanna [ORNL; Greenwood, Michael Scott [ORNL; Qualls, A L. [ORNL; Calderoni, Pattrick [Idaho National Laboratory (INL)
2017-12-01
This report summarizes physical, chemical, and engineering analyses that have been done to support the development of a test loop to study tritium migration in 2LiF-BeF2 salts. The loop will operate under turbulent flow and a schematic of the apparatus has been used to develop a model in Mathcad to suggest flow parameters that should be targeted in loop operation. The introduction of tritium into the loop has been discussed as well as various means to capture or divert the tritium from egress through a test assembly. Permeation was calculated starting with a Modelica model for a transport through a nickel window into a vacuum, and modifying it for a FLiBe system with an argon sweep gas on the downstream side of the permeation interface. Results suggest that tritium removal with a simple tubular permeation device will occur readily. Although this system is idealized, it suggests that rapid measurement capability in the loop may be necessary to study and understand tritium removal from the system.
International Nuclear Information System (INIS)
Deviren, Bayram; Keskin, Mustafa
2012-01-01
The dynamical aspects of a cylindrical Ising nanotube in the presence of a time-varying magnetic field are investigated within the effective-field theory with correlations and Glauber-type stochastic approach. Temperature dependence of the dynamic magnetizations, dynamic total magnetization, hysteresis loop areas and correlations are investigated in order to characterize the nature of dynamic transitions as well as to obtain the dynamic phase transition temperatures and compensation behaviors. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and core, i.e., five different types of compensation behaviors in the Néel classification nomenclature exist in the system. -- Highlights: ► Kinetic cylindrical Ising nanotube is investigated using the effective-field theory. ► The dynamic magnetizations, hysteresis loop areas and correlations are calculated. ► The effects of the exchange interactions have been studied in detail. ► Five different types of compensation behaviors have been found. ► Some characteristic phenomena are found depending on ratio of physical parameters.
Energy Technology Data Exchange (ETDEWEB)
Deviren, Bayram, E-mail: bayram.deviren@nevsehir.edu.tr [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)
2012-02-20
The dynamical aspects of a cylindrical Ising nanotube in the presence of a time-varying magnetic field are investigated within the effective-field theory with correlations and Glauber-type stochastic approach. Temperature dependence of the dynamic magnetizations, dynamic total magnetization, hysteresis loop areas and correlations are investigated in order to characterize the nature of dynamic transitions as well as to obtain the dynamic phase transition temperatures and compensation behaviors. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and core, i.e., five different types of compensation behaviors in the Néel classification nomenclature exist in the system. -- Highlights: ► Kinetic cylindrical Ising nanotube is investigated using the effective-field theory. ► The dynamic magnetizations, hysteresis loop areas and correlations are calculated. ► The effects of the exchange interactions have been studied in detail. ► Five different types of compensation behaviors have been found. ► Some characteristic phenomena are found depending on ratio of physical parameters.
DNA looping by FokI: the impact of twisting and bending rigidity on protein-induced looping dynamics
Laurens, Niels; Rusling, David A.; Pernstich, Christian; Brouwer, Ineke; Halford, Stephen E.; Wuite, Gijs J. L.
2012-01-01
Protein-induced DNA looping is crucial for many genetic processes such as transcription, gene regulation and DNA replication. Here, we use tethered-particle motion to examine the impact of DNA bending and twisting rigidity on loop capture and release, using the restriction endonuclease FokI as a test system. To cleave DNA efficiently, FokI bridges two copies of an asymmetric sequence, invariably aligning the sites in parallel. On account of the fixed alignment, the topology of the DNA loop is set by the orientation of the sites along the DNA. We show that both the separation of the FokI sites and their orientation, altering, respectively, the twisting and the bending of the DNA needed to juxtapose the sites, have profound effects on the dynamics of the looping interaction. Surprisingly, the presence of a nick within the loop does not affect the observed rigidity of the DNA. In contrast, the introduction of a 4-nt gap fully relaxes all of the torque present in the system but does not necessarily enhance loop stability. FokI therefore employs torque to stabilise its DNA-looping interaction by acting as a ‘torsional’ catch bond. PMID:22373924
Polarisation of microwave emission from reconnecting twisted coronal loops
Gordovskyy, M.; Browning, P. K.; Kontar, E. P.
2017-08-01
Context. Magnetic reconnection and particle acceleration due to the kink instability in twisted coronal loops can be a viable scenario for confined solar flares. Detailed investigation of this phenomenon requires reliable methods for observational detection of magnetic twist in solar flares, which may not be possible solely through extreme UV and soft X-ray thermal emission. Polarisation of microwave emission in flaring loops can be used as one of the detection criteria. Aims: The aim of this study is to investigate the effect of magnetic twist in flaring coronal loops on the polarisation of gyro-synchrotron microwave (GSMW) emission, and determine whether it could provide a means for magnetic twist detection. Methods: We consider time-dependent magnetohydrodynamic and test-particle models developed using the LARE3D and GCA codes to investigate twisted coronal loops that relax after kink instability. Synthetic GSMW emission maps (I and V Stokes components) are calculated using GX simulator. Results: It is found that flaring twisted coronal loops produce GSMW radiation with a gradient of circular polarisation across the loop. However, these patterns may be visible only for a relatively short period of time owing to fast magnetic reconfiguration after the instability. Their visibility also depends on the orientation and position of the loop on the solar disk. Typically, it would be difficult to see these characteristic polarisation patterns in a twisted loop seen from the top (I.e. close to the centre of the solar disk), but easier in a twisted loop seen from the side (I.e. observed very close to the limb).
Schwalbe, Birco; Schreiber, Michael
2015-01-01
HIV-1 infection is characterized by an ongoing replication leading to T-lymphocyte decline which is paralleled by the switch from CCR5 to CXCR4 coreceptor usage. To predict coreceptor usage, several computer algorithms using gp120 V3 loop sequence data have been developed. In these algorithms an occupation of the V3 positions 11 and 25, by one of the amino acids lysine (K) or arginine (R), is an indicator for CXCR4 usage. Amino acids R and K dominate at these two positions, but can also be identified at positions 9 and 10. Generally, CXCR4-viruses possess V3 sequences, with an overall positive charge higher than the V3 sequences of R5-viruses. The net charge is calculated by subtracting the number of negatively charged amino acids (D, aspartic acid and E, glutamic acid) from the number of positively charged ones (K and R). In contrast to D and E, which are very similar in their polar and acidic properties, the characteristics of the R guanidinium group differ significantly from the K ammonium group. However, in coreceptor predictive computer algorithms R and K are both equally rated. The study was conducted to analyze differences in infectivity and coreceptor usage because of R-to-K mutations at the V3 positions 9, 10 and 11. V3 loop mutants with all possible RRR-to-KKK triplets were constructed and analyzed for coreceptor usage, infectivity and neutralization by SDF-1α and RANTES. Virus mutants R9R10R11 showed the highest infectivity rates, and were inhibited more efficiently in contrast to the K9K10K11 viruses. They also showed higher efficiency in a virus-gp120 paired infection assay. Especially V3 loop position 9 was relevant for a switch to higher infectivity when occupied by R. Thus, K-to-R exchanges play a role for enhanced viral entry efficiency and should therefore be considered when the viral phenotype is predicted based on V3 sequence data.
High pressure experimental water loop
International Nuclear Information System (INIS)
Grenon, M.
1958-01-01
A high pressure experimental water loop has been made for studying the detection and evolution of cladding failure in a pressurized reactor. The loop has been designed for a maximum temperature of 360 deg. C, a maximum of 160 kg/cm 2 and flow rates up to 5 m 3 /h. The entire loop consists of several parts: a main circuit with a canned rotor circulation pump, steam pressurizer, heating tubes, two hydro-cyclones (one de-gasser and one decanter) and one tubular heat exchanger; a continuous purification loop, connected in parallel, comprising pressure reducing valves and resin pots which also allow studies of the stability of resins under pressure, temperature and radiation; following the gas separator is a gas loop for studying the recombination of the radiolytic gases in the steam phase. The preceding circuits, as well as others, return to a low pressure storage circuit. The cold water of the low pressure storage flask is continuously reintroduced into the high pressure main circuit by means of a return pump at a maximum head of 160 kg /cm 2 , and adjusted to the pressurizer level. This loop is also a testing bench for the tight high pressure apparatus. The circulating pump and the connecting flanges (Oak Ridge type) are water-tight. The feed pump and the pressure reducing valves are not; the un-tight ones have a system of leak recovery. To permanently check the tightness the circuit has been fitted with a leak detection system (similar to the HRT one). (author) [fr
Toward precision holography with supersymmetric Wilson loops
Energy Technology Data Exchange (ETDEWEB)
Faraggi, Alberto [Instituto de Física, Pontificia Universidad Católica de Chile,Casilla 306, Santiago (Chile); Zayas, Leopoldo A. Pando [The Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34014 Trieste (Italy); Michigan Center for Theoretical Physics, Department of Physics,University of Michigan, Ann Arbor, MI 48109 (United States); Silva, Guillermo A. [Instituto de Física de La Plata - CONICET & Departamento de Física - UNLP,C.C. 67, 1900 La Plata (Argentina); Trancanelli, Diego [Institute of Physics, University of São Paulo,05314-970 São Paulo (Brazil)
2016-04-11
We consider certain 1/4 BPS Wilson loop operators in SU(N)N=4 supersymmetric Yang-Mills theory, whose expectation value can be computed exactly via supersymmetric localization. Holographically, these operators are mapped to fundamental strings in AdS{sub 5}×S{sup 5}. The string on-shell action reproduces the large N and large coupling limit of the gauge theory expectation value and, according to the AdS/CFT correspondence, there should also be a precise match between subleading corrections to these limits. We perform a test of such match at next-to-leading order in string theory, by deriving the spectrum of quantum fluctuations around the classical string solution and by computing the corresponding 1-loop effective action. We discuss in detail the supermultiplet structure of the fluctuations. To remove a possible source of ambiguity in the ghost zero mode measure, we compare the 1/4 BPS configuration with the 1/2 BPS one, dual to a circular Wilson loop. We find a discrepancy between the string theory result and the gauge theory prediction, confirming a previous result in the literature. We are able to track the modes from which this discrepancy originates, as well as the modes that by themselves would give the expected result.
Quantum Loop Topography for Machine Learning
Zhang, Yi; Kim, Eun-Ah
2017-05-01
Despite rapidly growing interest in harnessing machine learning in the study of quantum many-body systems, training neural networks to identify quantum phases is a nontrivial challenge. The key challenge is in efficiently extracting essential information from the many-body Hamiltonian or wave function and turning the information into an image that can be fed into a neural network. When targeting topological phases, this task becomes particularly challenging as topological phases are defined in terms of nonlocal properties. Here, we introduce quantum loop topography (QLT): a procedure of constructing a multidimensional image from the "sample" Hamiltonian or wave function by evaluating two-point operators that form loops at independent Monte Carlo steps. The loop configuration is guided by the characteristic response for defining the phase, which is Hall conductivity for the cases at hand. Feeding QLT to a fully connected neural network with a single hidden layer, we demonstrate that the architecture can be effectively trained to distinguish the Chern insulator and the fractional Chern insulator from trivial insulators with high fidelity. In addition to establishing the first case of obtaining a phase diagram with a topological quantum phase transition with machine learning, the perspective of bridging traditional condensed matter theory with machine learning will be broadly valuable.
International Nuclear Information System (INIS)
Pertmer, G.A.; Almenas, K.; DiMarzo, M.; Bailery, S.
1989-01-01
This paper presents results of a series of Small Break LOCA tests performed at the University of Maryland 2 x 4 Loop, which is a 1/500 volume scaled model of a B and W PWR system. A feature of the B and W system which has a major impact on SBLOCA behavior is the Reactor Vessel Vent Valves, which provide a flow path between the upper plenum and downcomer in the vessel. This paper compares system behavior during a SBLOCA for two tests - one in which the valves are allowed to open, and one in which the valves are held closed. Similarities and differences between the system flow modes that occur during the transient are presented and discussed for the two tests
LISA Pathfinder: OPD loop characterisation
Born, Michael; LPF Collaboration
2017-05-01
The optical metrology system (OMS) of the LISA Pathfinder mission is measuring the distance between two free-floating test masses with unprecedented precision. One of the four OMS heterodyne interferometers reads out the phase difference between the reference and the measurement laser beam. This phase from the reference interferometer is common to all other longitudinal interferometer read outs and therefore subtracted. In addition, the phase is fed back via the digital optical pathlength difference (OPD) control loop to keep it close to zero. Here, we analyse the loop parameters and compare them to on-ground measurement results.
Mordi, Natalie A; Mordi, Ify R; Singh, Jagdeep S; Baig, Fatima; Choy, Anna-Maria; McCrimmon, Rory J; Struthers, Allan D; Lang, Chim C
2017-10-16
Type 2 diabetes (T2D) and heart failure (HF) are a frequent combination, where treatment options remain limited. There has been increasing interest around the sodium-glucose cotransporter 2 (SGLT2) inhibitors and their use in patients with HF. Data on the effect of SGLT2 inhibitor use with diuretics are limited. We hypothesise that SGLT2 inhibition may augment the effects of loop diuretics and the benefits of SGLT2 inhibitors may extend beyond those of their metabolic (glycaemic parameters and weight loss) and haemodynamic parameters. The effects of SGLT2 inhibitors as an osmotic diuretic and on natriuresis may underlie the cardiovascular and renal benefits demonstrated in the recent EMPA-REG study. To assess the effect of SGLT2 inhibitors when used in combination with a loop diuretic, the RECEDE-CHF (Renal and Cardiovascular Effects of SGLT2 inhibition in combination with loop Diuretics in diabetic patients with Chronic Heart Failure) trial is a single-centre, randomised, double-blind, placebo-controlled, cross-over trial conducted in a secondary care setting within NHS Tayside, Scotland. 34 eligible participants, aged between 18 and 80 years, with stable T2D and CHF will be recruited. Renal physiological testing will be performed at two points (week 1 and week 6) on each arm to assess the effect of 25 mg empagliflozin, on the primary and secondary outcomes. Participants will be enrolled in the trial for a total period between 14 and 16 weeks. The primary outcome will assess the effect of empagliflozin versus placebo on urine output. The secondary outcomes are to assess the effect of empagliflozin on glomerular filtration rate, cystatin C, urinary sodium excretion, urinary protein/creatinine ratio and urinary albumin/creatinine ratio when compared with placebo. Ethics approval was obtained by the East of Scotland Research Ethics Service. Results of the trial will be submitted for publication in a peer-reviewed journal. NCT03226457; Pre-results. © Article author
Fermions and loops on graphs: I. Loop calculus for determinants
International Nuclear Information System (INIS)
Chernyak, Vladimir Y; Chertkov, Michael
2008-01-01
This paper is the first in a series devoted to evaluation of the partition function in statistical models on graphs with loops in terms of the Berezin/fermion integrals. The paper focuses on a representation of the determinant of a square matrix in terms of a finite series, where each term corresponds to a loop on the graph. The representation is based on a fermion version of the loop calculus, previously introduced by the authors for graphical models with finite alphabets. Our construction contains two levels. First, we represent the determinant in terms of an integral over anti-commuting Grassmann variables, with some reparametrization/gauge freedom hidden in the formulation. Second, we show that a special choice of the gauge, called the BP (Bethe–Peierls or belief propagation) gauge, yields the desired loop representation. The set of gauge fixing BP conditions is equivalent to the Gaussian BP equations, discussed in the past as efficient (linear scaling) heuristics for estimating the covariance of a sparse positive matrix
Heating-related flows in cool solar loops
Klimchuk, J. A.; Mariska, J. T.
1988-01-01
The effects of spatial and temporal variations in the heating of cool loop models are investigated in an attempt to explain the net redshifts that are observed on the sun. The response of initially static cool loops to changes in the energy input is simulated. For hot loops, it is found that spatially asymmetric changes produce a final steady state that is dynamic, and that spatially symmetric changes produce a final state that is static. Some general properties of cool loop equilibria are discussed, emphasizing the relationship between structure and energy input. The results are unable to explain the net redshifts observed in emission lines formed near 100,000 K on the sun.
Nonlinear model predictive control for chemical looping process
Energy Technology Data Exchange (ETDEWEB)
Joshi, Abhinaya; Lei, Hao; Lou, Xinsheng
2017-08-22
A control system for optimizing a chemical looping ("CL") plant includes a reduced order mathematical model ("ROM") that is designed by eliminating mathematical terms that have minimal effect on the outcome. A non-linear optimizer provides various inputs to the ROM and monitors the outputs to determine the optimum inputs that are then provided to the CL plant. An estimator estimates the values of various internal state variables of the CL plant. The system has one structure adapted to control a CL plant that only provides pressure measurements in the CL loops A and B, a second structure adapted to a CL plant that provides pressure measurements and solid levels in both loops A, and B, and a third structure adapted to control a CL plant that provides full information on internal state variables. A final structure provides a neural network NMPC controller to control operation of loops A and B.
Conformal anomaly of generalized form factors and finite loop integrals
Chicherin, Dmitry
2017-01-01
We reveal a new mechanism of conformal symmetry breaking at Born level. It occurs in generalized form factors with several local operators and an on-shell state of massless particles. The effect is due to hidden singularities on collinear configurations of the momenta. This conformal anomaly is different from the holomorphic anomaly of amplitudes. We present a number of examples in four and six dimensions. We find an application of the new conformal anomaly to finite loop momentum integrals with one or more massless legs. The collinear region around a massless leg creates a contact anomaly, made visible by the loop integration. The anomalous conformal Ward identity for an $\\ell-$loop integral is a 2nd-order differential equation whose right-hand side is an $(\\ell-1)-$loop integral. We show several examples, in particular the four-dimensional scalar double box.
Fast-sausage oscillations in coronal loops with smooth boundary
Lopin, I.; Nagorny, I.
2014-12-01
Aims: The effect of the transition layer (shell) in nonuniform coronal loops with a continuous radial density profile on the properties of fast-sausage modes are studied analytically and numerically. Methods: We modeled the coronal waveguide as a structured tube consisting of a cord and a transition region (shell) embedded within a magnetic uniform environment. The derived general dispersion relation was investigated analytically and numerically in the context of frequency, cut-off wave number, and the damping rate of fast-sausage oscillations for various values of loop parameters. Results: The frequency of the global fast-sausage mode in the loops with a diffuse (or smooth) boundary is determined mainly by the external Alfvén speed and longitudinal wave number. The damping rate of such a mode can be relatively low. The model of coronal loop with diffuse boundary can support a comparatively low-frequency, global fast-sausage mode of detectable quality without involving extremely low values of the density contrast. The effect of thin transition layer (corresponds to the loops with steep boundary) is negligible and produces small reductions of oscillation frequency and relative damping rate in comparison with the case of step-function density profile. Seismological application of obtained results gives the estimated Alfvén speed outside the flaring loop about 3.25 Mm/s.
Feedback - closing the loop digitally
International Nuclear Information System (INIS)
Zagel, J.; Chase, B.
1992-01-01
Many feedback and feedforward systems are now using microprocessors within the loop. We describe the wide range of possibilities and problems that arise. We also propose some ideas for analysis and testing, including examples of motion control in the Flying Wire systems in Main Ring and Tevatron and Low Level RF control now being built for the Fermilab Linac upgrade. (author)
Two loops in eleven dimensions
Green, Michael B.; Vanhove, Pierre; Green, Michael B.; Kwon, Hwang-h.; Vanhove, Pierre
2000-01-01
The two-loop Feynman diagram contribution to the four-graviton amplitude of eleven-dimensional supergravity compactified on a two-torus, T^2, is analyzed in detail. The Schwinger parameter integrations are re-expressed as integration over the moduli space of a second torus, \\hat T^2, which enables the leading low-momentum contribution to be evaluated in terms of maps of \\hat T^2 into T^2. The ultraviolet divergences associated with boundaries of moduli space are regularized in a manner that is consistent with the expected duality symmetries of string theory. This leads to an exact expression for terms of order contraction of four Weyl tensors), thereby extending earlier results for the R^4 term that were based on the one-loop eleven-dimensional amplitude. Precise agreement is found with terms in type IIA and IIB superstring theory that arise from the low energy expansion of the tree-level and one-loop string amplitudes and predictions are made for the coefficients of certain two-loop string theory terms as we...
Loop quantum cosmology and singularities.
Struyve, Ward
2017-08-15
Loop quantum gravity is believed to eliminate singularities such as the big bang and big crunch singularity. This belief is based on studies of so-called loop quantum cosmology which concerns symmetry-reduced models of quantum gravity. In this paper, the problem of singularities is analysed in the context of the Bohmian formulation of loop quantum cosmology. In this formulation there is an actual metric in addition to the wave function, which evolves stochastically (rather than deterministically as the case of the particle evolution in non-relativistic Bohmian mechanics). Thus a singularity occurs whenever this actual metric is singular. It is shown that in the loop quantum cosmology for a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker space-time with arbitrary constant spatial curvature and cosmological constant, coupled to a massless homogeneous scalar field, a big bang or big crunch singularity is never obtained. This should be contrasted with the fact that in the Bohmian formulation of the Wheeler-DeWitt theory singularities may exist.
International Nuclear Information System (INIS)
Tiwari, Abhinav; Igoshin, Oleg A
2012-01-01
Biochemical regulatory networks governing diverse cellular processes such as stress-response, differentiation and cell cycle often contain coupled feedback loops. We aim at understanding how features of feedback architecture, such as the number of loops, the sign of the loops and the type of their coupling, affect network dynamical performance. Specifically, we investigate how bistability range, maximum open-loop gain and switching times of a network with transcriptional positive feedback are affected by additive or multiplicative coupling with another positive- or negative-feedback loop. We show that a network's bistability range is positively correlated with its maximum open-loop gain and that both quantities depend on the sign of the feedback loops and the type of feedback coupling. Moreover, we find that the addition of positive feedback could decrease the bistability range if we control the basal level in the signal-response curves of the two systems. Furthermore, the addition of negative feedback has the capacity to increase the bistability range if its dissociation constant is much lower than that of the positive feedback. We also find that the addition of a positive feedback to a bistable network increases the robustness of its bistability range, whereas the addition of a negative feedback decreases it. Finally, we show that the switching time for a transition from a high to a low steady state increases with the effective fold change in gene regulation. In summary, we show that the effect of coupled feedback loops on the bistability range and switching times depends on the underlying mechanistic details. (paper)
Energy Technology Data Exchange (ETDEWEB)
Christensen, M., E-mail: mchristensen@materialsdesign.com [Materials Design, Inc., 6 First National Place, Angel Fire, NM 87710 (United States); Wolf, W.; Freeman, C.; Wimmer, E. [Materials Design, Inc., 6 First National Place, Angel Fire, NM 87710 (United States); Adamson, R.B. [Zircology Plus, 36848 Montecito Dr, Fremont, CA 94536 (United States); Hallstadius, L. [Westinghouse Electric Sweden AB, SE-721 63 Västerås (Sweden); Cantonwine, P.E. [Global Nuclear Fuel – Americas, P.O. Box 780, M/C F12, Wilmington, NC 28402 (United States); Mader, E.V. [Electric Power Research Institute (EPRI), 3420 Hillview Ave, Palo Alto, CA 94303 (United States)
2015-05-15
Highlights: • Simulations of point defects in alpha-Zr using ab initio and forcefield methods. • Anisotropic strain dependent diffusion for interstitials and vacancies. • Explanation of pre-breakaway irradiation growth. • Interstitial nanoclusters cause expansion in 〈a〉, vacancy clusters contract 〈c〉. • H atoms diffuse isotropically, attracted to vacancy defects. - Abstract: Diffusion of point defects, nucleation of dislocation loops, and the associated dimensional changes of pure and H-loaded hcp-Zr have been investigated by a combination of ab initio calculations and classical simulations. Vacancy diffusion is computed to be anisotropic with D{sub vac,basal} = 8.6 × 10{sup −6} e{sup −Q/(RT)} (m{sup 2}/s) and D{sub vac,axial} = 9.9 × 10{sup −6} e{sup −Q/(RT)} (m{sup 2}/s), Q = 69 and 72 kJ/mol for basal and axial diffusion, respectively. At 550 K vacancy diffusion is about twice as fast in the basal plane as in a direction parallel to the c-axis. Diffusion of self-interstitials is found to be considerably faster and anisotropic involving collective atomic motions. At 550 K diffusion occurs predominantly in the a-directions, but this anisotropy diminishes with increasing temperature. Furthermore, the diffusion anisotropy is very dependent on the local strain (c/a ratio). Interstitial H atoms are found to diffuse isotropically with D{sub H} = 1.1 × 10{sup −7} e{sup −42/(RT)} (m{sup 2}/s). These results are consistent with experimental data and other theoretical studies. Molecular dynamics simulations at 550 K with periodic injection of vacancies and self-interstitial atoms reveal the formation of small nanoclusters, which are sufficient to cause a net expansion of the lattice in the a-directions driven by clusters of self-interstitials and a smaller contraction in the c-direction involving nanoclusters of vacancies. This is consistent with and can explain experimental data of irradiation growth. Energy minimizations show that vacancy
One-loop renormalization of the electroweak sector with Lorentz violation
International Nuclear Information System (INIS)
Colladay, Don; McDonald, Patrick
2009-01-01
The one-loop renormalizability of the electroweak sector of the standard model extension (SME) with Lorentz violation is studied. Functional determinants are used to calculate the one-loop contributions of the Higgs, gauge bosons and fermions to the one-loop effective action. The results are consistent with multiplicative renormalization of the SME coupling constants. Conventional electroweak symmetry breaking is effectively unaltered relative to the standard case as the renormalized SME parameters are sufficient to absorb all infinite contributions.
One-Loop Renormalization of the Electroweak Sector with Lorentz Violation
Colladay, Don; McDonald, Patrick
2009-01-01
The one-loop renormalizability of the electroweak sector of the Standard Model Extension with Lorentz violation is studied. Functional determinants are used to calculate the one-loop contributions of the higgs, gauge bosons and fermions to the one-loop effective action. The results are consistent with multiplicative renormalization of the SME coupling constants. Conventional Electroweak symmetry breaking is effectively unaltered relative to the standard case as the renormalized SME parameters...
On the one loop corrections to inflation and the CMB anisotropies
International Nuclear Information System (INIS)
Sloth, Martin S.
2006-01-01
We investigate the one loop effective potential of inflation in a standard model of chaotic inflation. The leading one loop corrections to the effective inflaton potential are evaluated in the quasi de Sitter background, and we estimate the one loop correction to the two-point function of the inflaton perturbations in the Hartree approximation. In this approximation, the one loop corrections depends on the total number of e-foldings of inflation and the maximal effect is estimated to be a correction to the power spectrum of a few percent. However, such a correction may be difficult to disentangle from the background in the simplest scenario
Saturating representation of loop conformational fragments in structure databanks
Directory of Open Access Journals (Sweden)
Fiser András
2006-07-01
Full Text Available Abstract Background Short fragments of proteins are fundamental starting points in various structure prediction applications, such as in fragment based loop modeling methods but also in various full structure build-up procedures. The applicability and performance of these approaches depend on the availability of short fragments in structure databanks. Results We studied the representation of protein loop fragments up to 14 residues in length. All possible query fragments found in sequence databases (Sequence Space were clustered and cross referenced with available structural fragments in Protein Data Bank (Structure Space. We found that the expansion of PDB in the last few years resulted in a dense coverage of loop conformational fragments. For each loops of length 8 in the current Sequence Space there is at least one loop in Structure Space with 50% or higher sequence identity. By correlating sequence and structure clusters of loops we found that a 50% sequence identity generally guarantees structural similarity. These percentages of coverage at 50% sequence cutoff drop to 96, 94, 68, 53, 33 and 13% for loops of length 9, 10, 11, 12, 13, and 14, respectively. There is not a single loop in the current Sequence Space at any length up to 14 residues that is not matched with a conformational segment that shares at least 20% sequence identity. This minimum observed identity is 40% for loops of 12 residues or shorter and is as high as 50% for 10 residue or shorter loops. We also assessed the impact of rapidly growing sequence databanks on the estimated number of new loop conformations and found that while the number of sequentially unique sequence segments increased about six folds during the last five years there are almost no unique conformational segments among these up to 12 residues long fragments. Conclusion The results suggest that fragment based prediction approaches are not limited any more by the completeness of fragments in databanks but
Directory of Open Access Journals (Sweden)
Glenn M Marshall
2011-06-01
Full Text Available The N-Myc oncoprotein is a critical factor in neuroblastoma tumorigenesis which requires additional mechanisms converting a low-level to a high-level N-Myc expression. N-Myc protein is stabilized when phosphorylated at Serine 62 by phosphorylated ERK protein. Here we describe a novel positive feedback loop whereby N-Myc directly induced the transcription of the class III histone deacetylase SIRT1, which in turn increased N-Myc protein stability. SIRT1 binds to Myc Box I domain of N-Myc protein to form a novel transcriptional repressor complex at gene promoter of mitogen-activated protein kinase phosphatase 3 (MKP3, leading to transcriptional repression of MKP3, ERK protein phosphorylation, N-Myc protein phosphorylation at Serine 62, and N-Myc protein stabilization. Importantly, SIRT1 was up-regulated, MKP3 down-regulated, in pre-cancerous cells, and preventative treatment with the SIRT1 inhibitor Cambinol reduced tumorigenesis in TH-MYCN transgenic mice. Our data demonstrate the important roles of SIRT1 in N-Myc oncogenesis and SIRT1 inhibitors in the prevention and therapy of N-Myc-induced neuroblastoma.
Directory of Open Access Journals (Sweden)
Byung Duk Song
2017-09-01
Full Text Available In the green manufacturing system that pursues the reuse of used products, the residual value of collected used products (CUP hugely affects a variety of managerial decisions to construct profitable and environmental remanufacturing plans. This paper deals with a closed-loop green manufacturing system for companies which perform both manufacturing with raw materials and remanufacturing with collected used products (CUP. The amount of CUP is assumed as a function of buy-back cost while the quality level of CUP, which means the residual value, follows a known distribution. In addition, the remanufacturing cost can differ according to the quality of the CUP. Moreover, nowadays companies are subject to existing environment-related laws such as Extended Producer Responsibility (EPR. Therefore, a company should collect more used products than its obligatory take-back quota or face fines from the government for not meeting its quota. Through the development of mathematical models, two kinds of inspection policies are examined to validate the efficiency of two different operation processes. To find a managerial solution, a genetic algorithm is proposed and tested with numerical examples.
Vertically Polarized Omnidirectional Printed Slot Loop Antenna
DEFF Research Database (Denmark)
Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper
2015-01-01
A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization.......A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...
Quenching phenomena in natural circulation loop
Energy Technology Data Exchange (ETDEWEB)
Umekawa, Hisashi; Ozawa, Mamoru [Kansai Univ., Osaka (Japan); Ishida, Naoki [Daihatsu Motor Company, Osaka (Japan)
1995-09-01
Quenching phenomena has been investigated experimentally using circulation loop of liquid nitrogen. During the quenching under natural circulation, the heat transfer mode changes from film boiling to nucleate boiling, and at the same time flux changes with time depending on the vapor generation rate and related two-phase flow characteristics. Moreover, density wave oscillations occur under a certain operating condition, which is closely related to the dynamic behavior of the cooling curve. The experimental results indicates that the occurrence of the density wave oscillation induces the deterioration of effective cooling of the heat surface in the film and the transition boiling regions, which results in the decrease in the quenching velocity.
Thermoelectric power generator with intermediate loop
Bell, Lon E; Crane, Douglas Todd
2013-05-21
A thermoelectric power generator is disclosed for use to generate electrical power from heat, typically waste heat. An intermediate heat transfer loop forms a part of the system to permit added control and adjustability in the system. This allows the thermoelectric power generator to more effectively and efficiently generate power in the face of dynamically varying temperatures and heat flux conditions, such as where the heat source is the exhaust of an automobile, or any other heat source with dynamic temperature and heat flux conditions.
Quenching phenomena in natural circulation loop
International Nuclear Information System (INIS)
Umekawa, Hisashi; Ozawa, Mamoru; Ishida, Naoki
1995-01-01
Quenching phenomena has been investigated experimentally using circulation loop of liquid nitrogen. During the quenching under natural circulation, the heat transfer mode changes from film boiling to nucleate boiling, and at the same time flux changes with time depending on the vapor generation rate and related two-phase flow characteristics. Moreover, density wave oscillations occur under a certain operating condition, which is closely related to the dynamic behavior of the cooling curve. The experimental results indicates that the occurrence of the density wave oscillation induces the deterioration of effective cooling of the heat surface in the film and the transition boiling regions, which results in the decrease in the quenching velocity
Pressure wave propagation in sodium loop
International Nuclear Information System (INIS)
Botelho, D.A.
1989-01-01
A study was done on the pressure wave propagation within the pipes and mixture vessel of a termohydraulic loop for thermal shock with sodium. It was used the characteristic method to solve the one-dimensional continuity and momentum equations. The numerical model includes the pipes and the effects of valves and other accidents on pressure losses. The study was based on designer informations and engineering tables. It was evaluated the pressure wave sizes, parametrically as a function of the draining valve closure times. (author) [pt
Assessing catchment connectivity using hysteretic loops
Davis, Jason; Masselink, Rens; Goni, Mikel; Gimenez, Rafael; Casali, Javier; Seeger, Manuel; Keesstra, Saskia
2017-04-01
Storm events mobilize large proportions of sediments in catchment systems. Therefore understanding catchment sediment dynamics throughout the continuity of storms and how initial catchment states act as controls on the transport of sediment to catchment outlets is important for effective catchment management. Sediment connectivity is a concept which can explain the origin, pathways and sinks of sediments within catchments (Baartman et al., 2013; Parsons et al., 2015; Masselink et al., 2016a,b; Mekonnen et al., 2016). However, sediment connectivity alone does not provide a practicable mechanism by which the catchment's initial state - and thus the location of entrained sediment in the sediment transport cascade - can be characterized. Studying the dynamic relationship between water discharge (Q) and suspended sediment (SS) at the catchment outlet can provide a valuable research tool to infer the likely source areas and flow pathways contributing to sediment transport because the relationship can be characterized by predictable hysteresis patterns. Hysteresis is observed when the sediment concentration associated with a certain flow rate is different depending on the direction in which the analysis is performed - towards the increase or towards the diminution of the flow. However, the complexity of the phenomena and factors which determine the hysteresis make its interpretation ambiguous. Previous work has described various types of hysteretic loops as well as the cause for the shape of the loop, mainly pointing to the origin of the sediments. The data set for this study comes from four experimental watersheds in Navarre (Spain), owned and maintained by the Government of Navarre. These experimental watersheds have been monitored and studied since 1996 (La Tejería and Latxaga) and 2001 (Oskotz principal and Oskotz woodland). La Tejería and Latxaga watersheds are similar to each other regarding size (approximately 200 ha), geology (marls and sandstones), soils (fine
Estimation of complex permittivity using loop antenna
DEFF Research Database (Denmark)
Lenler-Eriksen, Hans-Rudolph; Meincke, Peter
2004-01-01
A method for estimating the complex permittivity of materials in the vicinity of a loop antenna is proposed. The method is based on comparing measured and numerically calculated input admittances for the loop antenna.......A method for estimating the complex permittivity of materials in the vicinity of a loop antenna is proposed. The method is based on comparing measured and numerically calculated input admittances for the loop antenna....
Verifying parallel loops with separation logic
Blom, Stefan; Darabi, Saeed; Huisman, Marieke
2014-01-01
This paper proposes a technique to specify and verify whether a loop can be parallelised. Our approach can be used as an additional step in a parallelising compiler to verify user annotations about loop dependences. Essentially, our technique requires each loop iteration to be specified with the
DEFF Research Database (Denmark)
Schaub Jr, Gary John; Kristoffersen, Jens Wenzel
being the degree of sophist ication of weapon responses to external stimuli. Such weapons can be controlled directly with a “man-in-the-loop,” managed by a “man-on-the-loop,” or supervised by a “man-out-of-the-loop.” Although all uses of force by Western militaries take place within an institution...
Kiechle, Hubert
2002-01-01
The book contains the first systematic exposition of the current known theory of K-loops, as well as some new material. In particular, big classes of examples are constructed. The theory for sharply 2-transitive groups is generalized to the theory of Frobenius groups with many involutions. A detailed discussion of the relativistic velocity addition based on the author's construction of K-loops from classical groups is also included. The first chapters of the book can be used as a text, the later chapters are research notes, and only partially suitable for the classroom. The style is concise, but complete proofs are given. The prerequisites are a basic knowledge of algebra such as groups, fields, and vector spaces with forms.
Loop connectors in dentogenic diastema
Directory of Open Access Journals (Sweden)
Sanjna Nayar
2015-01-01
Full Text Available Patients with a missing tooth along with diastema have limited treatment options to restore the edentulous space. The use of a conventional fixed partial denture (FPD to replace the missing tooth may result in too wide anterior teeth leading to poor esthetics. Loss of anterior teeth with existing diastema may result in excess space available for pontic. This condition presents great esthetic challenge for prosthodontist. If implant supported prosthesis is not possible because of inadequate bone support, FPD along with loop connector may be a treatment option to maintain the diastema and provide optimal esthetic restoration. Here, we report a clinical case where FPD along with loop connector was used to achieve esthetic rehabilitation in maxillary anterior region in which midline diastema has been maintained.
Trouble with boson loops in Skyrmion physics
International Nuclear Information System (INIS)
Aitchison, I.J.R.; Fraser, C.M.
1985-01-01
The possibility is raised that the O((partialphi) 4 ) (stability) terms in the Skyrme Lagrangian may arise as quantum corrections, starting from an underlying bosonic field theory. Specifically, these terms are calculated from a derivative expansion of the one-loop effective action of the linear sigma model, which is the simplest relevant theory. The calculated terms are logarithmically divergent in the chiral limit m/sub π/ 2 →0. This physically incorrect result is traced to a failure of the derivative expansion caused by nonanalyticity of the Green's functions at zero momentum (i.e., unitarity thresholds). The difficulties of handling ''light'' particle loops in the effective-Lagrangian approach to soliton physics are discussed. It is suggested that, in the absence of a systematic procedure for calculating unitarity corrections to effective Lagrangians, it may be more fruitful to settle for an approximate theory, in which the soliton Lagrangian is enlarged to include heavier mesons, and used only at the tree level
Sarri, Margarita; Greenwood, Richard; Kalra, Lalit; Papps, Ben; Husain, Masud; Driver, Jon
2008-01-01
Prism adaptation to rightward optical shifts during visually guided pointing is considered a promising intervention in right-hemisphere stroke patients with left spatial neglect. Conventionally, prism adaptation is assessed via aftereffects, on subjective straight ahead (SSA) pointing with eyes closed; or by visual open-loop pointing (VOL), i.e. pointing to a visual target without seeing the hand. Previous data suggest indirectly that prism aftereffects in neglect patients may be larger (pathologically so) when assessed by SSA than by VOL. But these measures have never been directly compared within the same patients after identical prism exposure. Accordingly we implemented both measures here within the same group of 13 neglect patients and 13 controls. Prism aftereffects were much larger for SSA than VOL in neglect patients, falling outside the normative range only for SSA. This may arise because the SSA task can itself involve aspects of neglect that may be ameliorated by the prism intervention, hence showing abnormal changes after prisms. The extent of SSA change after prisms varied between patients, and correlated with improvements on a standard cancellation measure for neglect. The lesions of patients who did versus did not show neglect improvement immediately after prisms provide an initial indication that lack of improvement may potentially relate to cortical damage in right intraparietal sulcus and white matter damage in inferior parietal lobe and middle frontal gyrus. Future studies of possible rehabilitative impact from prisms upon neglect may need to consider carefully how to measure prism adaptation per se, separately from any impact of such adaptation upon manifestations of neglect. PMID:18083203
Directory of Open Access Journals (Sweden)
Avinash J. Gaikwad
2008-01-01
Full Text Available Provision of passive means to reactor core decay heat removal enhances the nuclear power plant (NPP safety and availability. In the earlier Indian pressurised heavy water reactors (IPHWRs, like the 220 MWe and the 540 MWe, crash cooldown from the steam generators (SGs is resorted to mitigate consequences of station blackout (SBO. In the 700 MWe PHWR currently being designed an additional passive decay heat removal (PDHR system is also incorporated to condense the steam generated in the boilers during a SBO. The sustainability of natural circulation in the various heat transport systems (i.e., primary heat transport (PHT, SGs, and PDHRs under station blackout depends on the corresponding system's coolant inventories and the coolant circuit configurations (i.e., parallel paths and interconnections. On the primary side, the interconnection between the two primary loops plays an important role to sustain the natural circulation heat removal. On the secondary side, the steam lines interconnections and the initial inventory in the SGs prior to cooldown, that is, hooking up of the PDHRs are very important. This paper attempts to open up discussions on the concept and the core issues associated with passive systems which can provide continued heat sink during such accident scenarios. The discussions would include the criteria for design, and performance of such concepts already implemented and proposes schemes to be implemented in the proposed 700 MWe IPHWR. The designer feedbacks generated, and critical examination of performance analysis results for the added passive system to the existing generation II & III reactors will help ascertaining that these safety systems/inventories in fact perform in sustaining decay heat removal and augmenting safety.
On the One Loop Corrections to Inflation II
DEFF Research Database (Denmark)
Sloth, Martin Snoager
2006-01-01
In this paper we extend our previous treatment of the one-loop corrections to inflation. Previously we calculated the one-loop corrections to the background and the two-point correlation function of inflaton fluctuations in a specific model of chaotic inflation. We showed that the loop corrections...... depend on the total number of e-foldings and estimated that the effect could be as large as a few percent in a lambda-phi-four model of chaotic inflation. In the present paper we generalize the calculations to general inflationary potentials. We find that effect can be as large as 70% in the simplest...... model of chaotic inflation with a quadratic inflationary potential. We discuss the physical interpretation of the effect in terms of the tensor-to-scalar consistency relation. Finally, we discuss the relation to the work of Weinberg on quantum contributions to cosmological correlators....
Modular invariance and covariant loop calculus
International Nuclear Information System (INIS)
Petersen, J.L.; Roland, K.O.; Sidenius, J.R.
1988-01-01
The covariant loop calculus provides an efficient technique for computing explicit expressions for the density on moduli space corresponding to arbitrary (bosonic string) loop diagrams. Since modular invariance is not manifest, however, we carry out a detailed comparison with known explicit two- and three-loop results derived using analytic geometry (one loop is known to be okay). We establish identity to 'high' order in some moduli and exactly in others. Agreement is found as a result of various nontrivial cancellations, in part related to number theory. We feel our results provide very strong support for the correctness of the covariant loop calculus approach. (orig.)
Modular invariance and covariant loop calculus
International Nuclear Information System (INIS)
Petersen, J.L.; Roland, K.O.; Sidenius, J.R.
1988-01-01
The covariant loop calculus provides and efficient technique for computing explicit expressions for the density on moduli space corresponding to arbitrary (bosonic string) loop diagrams. Since modular invariance is not manifest, however, we carry out a detailed comparison with known explicit 2- and 3- loop results derived using analytic geometry (1 loop is known to be ok). We establish identity to 'high' order in some moduli and exactly in others. Agreement is found as a result of various non-trivial cancellations, in part related to number theory. We feel our results provide very strong support for the correctness of the covariant loop calculus approach. (orig.)
Kaveh M. Cyrus; Davide Aloini; Samira Karimzadeh
2018-01-01
Successful Enterprise Resource Planning (ERP) implementation depends upon various factors known as critical success factors (CSFs). This study developed a system dynamics model of ERP implementation based on CSFs to discuss ERP implementation complexities, which identifies the effect of CSF interrelations on different aspects of ERP project failure. Based on the model hypothesis, CSF interrelations include many causal loop dependencies. Some of these causal loops are called mortal loops, beca...
One-loop counterterms for dimensionally reduced quantum gravity
International Nuclear Information System (INIS)
Atkatz, D.
1980-01-01
The technique of regularization by dimensional reduction is applied to source-free quantum gravity. The one-loop counterterms for the effective gravity-matter system are calculated in the background field formalism. The ersatz matter fields which arise in this regularization scheme are found to have no effect on the renormalizability of the theory. (orig.)
Gaugino condensation, loop corrections and S-duality constraint
International Nuclear Information System (INIS)
Saririan, K.; California Univ., Berkeley, CA
1996-11-01
This talk is a brief review of gaugino condensation in superstring effective field theories and some related issues (such as renormalization of the gauge coupling in the effective supergravity theories and modular anomaly cancellation). As a specific example, we discuss a model containing perturbative (1-loop) corrections to the Kaehler potential and approximate S-duality symmetry
Use of percutaneous thread loop to hold the vermiform appendix during laparoscopic appendectomy.
Joshi, M R; Shrestha, S K; Thapa, P B; Koirala, U; Bhattarai, P; Dongol, U M S; Singh, D R; Sharma, S K
2007-01-01
Laparoscopic appendectomy, although not as widely performed as laparoscopic cholecystectomy, it has got definite advantage over the conventional open procedure. Controversy exists regarding the closure of stump. Our institute practices intracorporeal knot tying using 3 ports. Difficulties are observed in three port technique to hold the appendix during knot tying. We use a percutaneous thread loop. Advantage of the use of loop was evaluated. Prospective study was carried out during 18 months. Total cases were randomly divided in non-loop and with loop group. Operative procedure was same. Cases were compared in terms of operating time, post-operative hospital stay and complications. Total patients were 66. Thirty two in non-loop group and 34 in with loop group. Mean age was 27.89 yrs. Most of the cases were females (62%). Mean operating time was less in loop group although statistically not significant. There was no difference in post operative hospital stay. Use of loop was not associated with added complications. Use of percutaneous loop to hold the appendix reduces the operating time and replaces the need of fourth port. It is safe and effective without any increased morbidity. Key words: Laparoscopic appendectomy, Intracorporeal knot, Percutaneous loop.
Loop technique for mitral valve repair.
Shibata, Toshihiko
2014-02-01
A new artificial chordal reconstruction technique has been developed using several expanded polytetrafluoroethylene (ePTFE) loops. This technique differs from conventional artificial chordal reconstruction in the use of premeasured ePTFE loops. The loop technique involves several steps: (1) assessment of the corresponding papillary muscle; (2) measurement of the required ePTFE loop length; (3) making a loop set of the premeasured length; (4) anchoring the loop set to the papillary muscle; (5) fixing the ePTFE loops to the prolapsing leaflet; (6) adjusting the loop length if necessary; and (7) ring implantation. Favorable early and mid-term results of this loop technique have been reported in patients undergoing mitral valve repair through mini-thoracotomy and via median sternotomy, with 3-year survival and re-operation-free rates of 94.8 and 97.4 %, respectively. The loop technique using ePTFE chordal reconstruction with premeasured loops thus appears to be a safe, reliable, and reproducible technique for mitral valve repair. In addition, it is suitable for both minimally invasive and conventional sternotomy approaches, and represents a useful technique for treating posterior, anterior, and especially bi-leaflet prolapses.
Hyperstaticity and loops in frictional granular packings
Tordesillas, Antoinette; Lam, Edward; Metzger, Philip T.
2009-06-01
The hyperstatic nature of granular packings of perfectly rigid disks is analyzed algebraically and through numerical simulation. The elementary loops of grains emerge as a fundamental element in addressing hyperstaticity. Loops consisting of an odd number of grains behave differently than those with an even number. For odd loops, the latent stresses are exterior and are characterized by the sum of frictional forces around each loop. For even loops, the latent stresses are interior and are characterized by the alternating sum of frictional forces around each loop. The statistics of these two types of loop sums are found to be Gibbsian with a "temperature" that is linear with the friction coefficient μ when μ<1.
ABJM Wilson loops in arbitrary representations
International Nuclear Information System (INIS)
Hatsuda, Yasuyuki; Moriyama, Sanefumi; Okuyama, Kazumi
2013-06-01
We study vacuum expectation values (VEVs) of circular half BPS Wilson loops in arbitrary representations in ABJM theory. We find that those in hook representations are reduced to elementary integrations thanks to the Fermi gas formalism, which are accessible from the numerical studies similar to the partition function in the previous studies. For non-hook representations, we show that the VEVs in the grand canonical formalism can be exactly expressed as determinants of those in the hook representations. Using these facts, we can study the instanton effects of the VEVs in various representations. Our results are consistent with the worldsheet instanton effects studied from the topological string and a prescription to include the membrane instanton effects by shifting the chemical potential, which has been successful for the partition function.
ABJM Wilson loops in arbitrary representations
Energy Technology Data Exchange (ETDEWEB)
Hatsuda, Yasuyuki [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Honda, Masazumi [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst. and Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics
2013-06-15
We study vacuum expectation values (VEVs) of circular half BPS Wilson loops in arbitrary representations in ABJM theory. We find that those in hook representations are reduced to elementary integrations thanks to the Fermi gas formalism, which are accessible from the numerical studies similar to the partition function in the previous studies. For non-hook representations, we show that the VEVs in the grand canonical formalism can be exactly expressed as determinants of those in the hook representations. Using these facts, we can study the instanton effects of the VEVs in various representations. Our results are consistent with the worldsheet instanton effects studied from the topological string and a prescription to include the membrane instanton effects by shifting the chemical potential, which has been successful for the partition function.
A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.
Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A
2005-11-01
While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.
Perturbation calculations with Wilson loop
International Nuclear Information System (INIS)
Peixoto Junior, L.B.
1984-01-01
We present perturbative calculations with the Wilson loop (WL). The dimensional regularization method is used with a special attention concerning to the problem of divergences in the WL expansion in second and fourth orders, in three and four dimensions. We show that the residue in the pole, in 4d, of the fourth order graphs contribution sum is important for the charge renormalization. We compute up to second order the exact expression of the WL, in three-dimensional gauge theories with topological mass as well as its assimptotic behaviour for small and large distances. the author [pt
Current control loop design and analysis based on resonant regulators for microgrid applications
DEFF Research Database (Denmark)
Federico, de Bosio; Pastorelli, Michelle; de Sousa Ribeiro, Luiz Antonio
2015-01-01
Voltage and current control loops play an important role in the performance of microgrids employing power electronics voltage source inverters. Correct design of feedback loops is essential for the proper operation of these systems. This paper analyzes the influence of state feedback cross......-coupling in the design of resonant regulators for inner current loops in power converters operating in standalone microgrids. It is also demonstrated that the effect of state feedback cross-coupling degrades the performance of the control loops by increasing the steady-state error. Different resonant regulators...
TRANSVERSE OSCILLATIONS OF SYSTEMS OF CORONAL LOOPS
International Nuclear Information System (INIS)
Luna, M.; Oliver, R.; Ballester, J. L.; Terradas, J.
2009-01-01
We study the collective kinklike normal modes of a system of several cylindrical loops using the T-matrix theory. Loops that have similar kink frequencies oscillate collectively with a frequency which is slightly different from that of the individual kink mode. On the other hand, if the kink frequency of a loop is different from that of the others, it oscillates individually with its own frequency. Since the individual kink frequency depends on the loop density but not on its radius for typical 1 MK coronal loops, a coupling between kink oscillations of neighboring loops takes place when they have similar densities. The relevance of these results in the interpretation of the oscillations studied by Schrijver and Brown in 2000 and Verwichte et al. in 2004, in which transverse collective loop oscillations seem to be detected, is discussed. In the first case, two loops oscillating in antiphase are observed; interpreting this motion as a collective kink mode suggests that their densities are roughly equal. In the second case, there are almost three groups of tubes that oscillate with similar periods, and therefore their dynamics can be collective, which again seems to indicate that the loops of each group share a similar density. All the other loops seem to oscillate individually and their densities can be different from the rest.
Gauge theory loop operators and Liouville theory
Energy Technology Data Exchange (ETDEWEB)
Drukker, Nadav [Humboldt Univ. Berlin (Germany). Inst. fuer Physik; Gomis, Jaume; Okuda, Takuda [Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada); Teschner, Joerg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2009-10-15
We propose a correspondence between loop operators in a family of four dimensional N=2 gauge theories on S{sup 4} - including Wilson, 't Hooft and dyonic operators - and Liouville theory loop operators on a Riemann surface. This extends the beautiful relation between the partition function of these N=2 gauge theories and Liouville correlators found by Alday, Gaiotto and Tachikawa. We show that the computation of these Liouville correlators with the insertion of a Liouville loop operator reproduces Pestun's formula capturing the expectation value of a Wilson loop operator in the corresponding gauge theory. We prove that our definition of Liouville loop operators is invariant under modular transformations, which given our correspondence, implies the conjectured action of S-duality on the gauge theory loop operators. Our computations in Liouville theory make an explicit prediction for the exact expectation value of 't Hooft and dyonic loop operators in these N=2 gauge theories. The Liouville loop operators are also found to admit a simple geometric interpretation within quantum Teichmueller theory as the quantum operators representing the length of geodesics. We study the algebra of Liouville loop operators and show that it gives evidence for our proposal as well as providing definite predictions for the operator product expansion of loop operators in gauge theory. (orig.)
On the determination of loop nature in the TEM
International Nuclear Information System (INIS)
Jenkins, M.L.
1997-01-01
The two direct methods available for determining the nature of small clusters, were studied. Experiments in heavy-ion irradiated Ag and Cu, including comparisons with Black-White contrast analysis (B-W), forced us to conclude that use of the 2-1/2D technique for analysis of faulted loops is impossible because of reciprocal-lattice spike and other effects. We used B-W analysis to study the clusters produced by RT heavy-ion irradiation of Cu. In-situ irradiations were performed in Argonne HVEM-Tandem Facility using 40 and 80 keV Kr + ions. Nearly all the analysable first-layer loops were vacancy in nature. Some deeper cluster were also certainly vacancy. There is no unequivocal evidence for interstitial loops under these conditions. The near impossibility of establishing that interstitial loops are not present, is shown by the fact that a large fraction of loops (over 50%) could not be analyzed either because they did not display clear B-W contrast under any condition or sufficiently consistent B-W contrast under several different operating conditions
Closed Loop Requirements and Analysis Management
Lamoreaux, Michael; Verhoef, Brett
2015-01-01
Effective systems engineering involves the use of analysis in the derivation of requirements and verification of designs against those requirements. The initial development of requirements often depends on analysis for the technical definition of specific aspects of a product. Following the allocation of system-level requirements to a product's components, the closure of those requirements often involves analytical approaches to verify that the requirement criteria have been satisfied. Meanwhile, changes that occur in between these two processes need to be managed in order to achieve a closed-loop requirement derivation/verification process. Herein are presented concepts for employing emerging Team center capabilities to jointly manage requirements and analysis data such that analytical techniques are utilized to effectively derive and allocate requirements, analyses are consulted and updated during the change evaluation processes, and analyses are leveraged during the design verification process. Recommendations on concept validation case studies are also discussed.
One-loop corrections to vector Galileon theory
Charmchi, Farid; Haghani, Zahra; Shahidi, Shahab; Shahkarami, Leila
2016-06-01
The effective action of the recently proposed vector Galileon theory is considered. Using the background field method, we obtain the one-loop correction to the propagator of the Proca field from vector Galileon self-interactions. Contrary to the so-called scalar Galileon interactions, the two-point function of the vector field gets renormalized at the one-loop level, indicating that there is no nonrenormalization theorem in the vector Galileon theory. Using dimensional regularization, we remove the divergences and obtain the counterterms of the theory. The finite term is analytically calculated, which modifies the propagator and the mass term and generates some new terms also.
From maximal to minimal supersymmetry in string loop amplitudes
Berg, Marcus; Buchberger, Igor; Schlotterer, Oliver
2017-04-01
We calculate one-loop string amplitudes of open and closed strings with N = 1 , 2 , 4 supersymmetry in four and six dimensions, by compactification on Calabi-Yau and K3 orbifolds. In particular, we develop a method to combine contributions from all spin structures for arbitrary number of legs at minimal supersymmetry. Each amplitude is cast into a compact form by reorganizing the kinematic building blocks and casting the worldsheet integrals in a basis. Infrared regularization plays an important role to exhibit the expected factorization limits. We comment on implications for the one-loop string effective action.
Virtual Induction Loops Based on Cooperative Vehicular Communications
Gramaglia, Marco; Bernardos, Carlos J.; Calderon, Maria
2013-01-01
Induction loop detectors have become the most utilized sensors in traffic management systems. The gathered traffic data is used to improve traffic efficiency (i.e., warning users about congested areas or planning new infrastructures). Despite their usefulness, their deployment and maintenance costs are expensive. Vehicular networks are an emerging technology that can support novel strategies for ubiquitous and more cost-effective traffic data gathering. In this article, we propose and evaluate VIL (Virtual Induction Loop), a simple and lightweight traffic monitoring system based on cooperative vehicular communications. The proposed solution has been experimentally evaluated through simulation using real vehicular traces. PMID:23348033
Virtual Induction Loops Based on Cooperative Vehicular Communications
Directory of Open Access Journals (Sweden)
Maria Calderon
2013-01-01
Full Text Available Induction loop detectors have become the most utilized sensors in traffic management systems. The gathered traffic data is used to improve traffic efficiency (i.e., warning users about congested areas or planning new infrastructures. Despite their usefulness, their deployment and maintenance costs are expensive. Vehicular networks are an emerging technology that can support novel strategies for ubiquitous and more cost-effective traffic data gathering. In this article, we propose and evaluate VIL (Virtual Induction Loop, a simple and lightweight traffic monitoring system based on cooperative vehicular communications. The proposed solution has been experimentally evaluated through simulation using real vehicular traces.
Empirical sigma - d relations and main galactic radio loops
Directory of Open Access Journals (Sweden)
Urošević Dejan V.
2002-01-01
Full Text Available This paper represents a review of the empirical Galactic and extragalactic sigma - D relations (relations between the surface brightness sigma and the diameter D for supernova remnants (SNRs, with checking the connection of the main Galactic radio loops (Loop I, II, III and IV with these relations. We present results which suggest, in another way, that the radio loops may have an SNR origin. The updated relations have been measured to have slopes beta = 2 in log-log space. The best sigma - D relations for M31 and M33 galaxies were derived and these relations are shown to be flatter (beta < 2 than those for Galactic SNRs alone. This result confirms that selection effects play an important role in data-sets made up of Galactic SNRs. A sigma - D relation with 157 reliable calibrators (both Galactic and extragalactic is derived. This relation also has a slope beta = 2.07 ± 13.
3 (and even 4) loops renormalization constants for Lattice QCD
International Nuclear Information System (INIS)
Di Renzo, F.; Mantovi, A.; Miccio, V.; Scorzato, L.; Torrero, C.
2006-01-01
We compute renormalization constants for Lattice QCD by means of Numerical Stochastic Perturbation Theory. As an example we discuss Wilson quark bilinears and in particular the 'gold plated' case of Z p /Z s for which we can evaluate the perturbative series up to four loops. By making use of the knowledge of anomalous dimension up to 3 loops in the RI'-MOM scheme, the generic bilinears ca be computed to the same (3rd) order. Finite volume effects are carefully assessed and the continuum limit of the computation is taken in a clean way. The convergence properties of the series can be assessed and a comparison with non-perturbative evaluations of the same quantities can be done. In the end, Lattice Perturbation Theory to high loops is a valuable tool to evaluate renormalization constants for lattice QCD with a very high precision
Superhorizon electromagnetic field background from Higgs loops in inflation
Kaya, Ali
2018-03-01
If Higgs is a spectator scalar, i.e. if it is not directly coupled to the inflaton, superhorizon Higgs modes must have been exited during inflation. Since Higgs is unstable its decay into photons is expected to seed superhorizon photon modes. We use in-in perturbation theory to show that this naive physical expectation is indeed fulfilled via loop effects. Specifically, we calculate the first order Higgs loop correction to the magnetic field power spectrum evaluated at some late time after inflation. It turns out that this loop correction becomes much larger than the tree-level power spectrum at the superhorizon scales. This suggests a mechanism to generate cosmologically interesting superhorizon vector modes by scalar-vector interactions.
Method for solving logical loops in system reliability analysis
International Nuclear Information System (INIS)
Matsuoka, Takeshi
2010-01-01
The procedure for solving Boolean equations with unknown element(s) is presented. Discussions are made for operation of typical engineering systems with loop structure. It is revealed that components are necessary to be classified into three types. Time-dependent expression of a component's state is given and operating states of loop structures are identified by Boolean algebraic procedure. The procedure proposed in this paper is applicable to the condition that components can start at any time in system operational sequence, and each component has multiple chances to be started. A sample system was analyzed and the result was confirmed by a step by step analysis. The procedure shown in this paper is very useful in evaluating engineering systems which have logical loop structure(s), and also useful in effectively designing high reliable systems. (author)
3D DD modelling of the prismatic loops and dislocations interaction in pure iron
International Nuclear Information System (INIS)
Novokshanov, R.; Roberts, S.
2007-01-01
Full text of publication follows: Neutron irradiation can increase the yield stress and reduce the ductility of metals. These effects are mainly caused by the interaction of dislocations with damage produced during irradiation. In iron irradiated with fast neutrons the damage takes the form of 1/2 and 1/2 prismatic dislocation loops (the size of the loops varies from 2 nm to 20 nm depending on the dose of irradiation). The interaction between such loops and dislocations is the subject of this research. 3D dislocation dynamics simulations have been carried out to model the interaction between prismatic loops and dis- locations in pure iron subject to uniaxial loading conditions. The primary goal was to understand the mechanism of interaction of a a/2 loop and a mobile dislocation. The simulations have shown a complicated 3D interaction resulting in either bowing around an obstacle (prismatic loop, Orowan mechanism) or cutting it through, carrying part of the loop away and leaving the other part behind. Cross-slip can be important, in a manner depending on the type of mobile dislocation, size, type and orientation of prismatic loop. The secondary goal was to investigate the dependence of the critical stress needed for dislocations to overcome the obstacles as a function of: size of loops, initial separation between loops, the direction of motion of the mobile dislocation and its type (pure edge or screw), and type of a loop (interstitial or vacancy). Many different configurations have been simulated. The size of the loops was varied from 10 nm to 100 nm; the separation between the loops in a row was varied from one to four loop diameters; the distance between the glide plane and the loop plane was varied from 0 to 20 nm. The glide plane of the mobile dislocation was either perpendicular to and or inclined to the loop plane. The results show a strong dependence of the critical stress on the size of the loops and the initial configuration. (authors)
Piecewise linear loop quantum gravity
Energy Technology Data Exchange (ETDEWEB)
Engle, Jonathan [MPI fuer Gravitationsphysik (Albert-Einstein-Institut), Am Muehlenberg 1, D-14476 Potsdam (Germany)
2010-02-07
We define a modification of loop quantum gravity (LQG) in which graphs are required to consist of piecewise linear edges, which we call piecewise linear LQG (plLQG). At the diffeomorphism-invariant level, we prove that plLQG is equivalent to standard LQG, as long as one chooses the class of diffeomorphisms appropriately. That is, we exhibit a unitary map between the diffeomorphism-invariant Hilbert spaces that maps physically equivalent operators into each other. In addition, using the same ideas as in standard LQG, one can define a Hamiltonian and master constraint in plLQG, and the unitary map between plLQG and LQG then provides an exact isomorphism of dynamics in the two frameworks. Furthermore, loop quantum cosmology (LQC) can be exactly embedded into plLQG. This allows a prior program of the author to embed LQC into LQG at the dynamical level to proceed. In particular, this allows a formal expression for a physically motivated embedding of LQC into LQG at the diffeomorphism-invariant level to be given.
Directory of Open Access Journals (Sweden)
Hui Zhang
Full Text Available It is well known that noise is inevitable in gene regulatory networks due to the low-copy numbers of molecules and local environmental fluctuations. The prediction of noise effects is a key issue in ensuring reliable transmission of information. Interlinked positive and negative feedback loops are essential signal transduction motifs in biological networks. Positive feedback loops are generally believed to induce a switch-like behavior, whereas negative feedback loops are thought to suppress noise effects. Here, by using the signal sensitivity (susceptibility and noise amplification to quantify noise propagation, we analyze an abstract model of the Myc/E2F/MiR-17-92 network that is composed of a coupling between the E2F/Myc positive feedback loop and the E2F/Myc/miR-17-92 negative feedback loop. The role of the feedback loop on noise effects is found to depend on the dynamic properties of the system. When the system is in monostability or bistability with high protein concentrations, noise is consistently suppressed. However, the negative feedback loop reduces this suppression ability (or improves the noise propagation and enhances signal sensitivity. In the case of excitability, bistability, or monostability, noise is enhanced at low protein concentrations. The negative feedback loop reduces this noise enhancement as well as the signal sensitivity. In all cases, the positive feedback loop acts contrary to the negative feedback loop. We also found that increasing the time scale of the protein module or decreasing the noise autocorrelation time can enhance noise suppression; however, the systems sensitivity remains unchanged. Taken together, our results suggest that the negative/positive feedback mechanisms in coupled feedback loop dynamically buffer noise effects rather than only suppressing or amplifying the noise.
A True Open-Loop Synchronization Technique
DEFF Research Database (Denmark)
Golestan, Saeed; Vidal, Ana; Yepes, Alejandro G.
2016-01-01
in a parallel manner. In the presence of the frequency feedback loop, nevertheless, the OLS technique may not be truly open-loop, which makes a deep study of stability necessary. Using the secondary frequency detector, on the other hand, increases the computational effort and implementation complexity. Another......Synchronization techniques can be broadly classified into two major categories: Closed-loop and open-loop methods. The open-loop synchronization (OLS) techniques, contrary to the closed-loop ones, are unconditionally stable and benefit from a fast dynamic response. Their performance, however, tends...... to worsen in the presence of frequency drifts. To deal with this problem, two approaches are often recommended in the literature: Adapting OLS techniques to grid frequency variations by feeding back the frequency estimated by them or using the frequency estimated by a secondary frequency detector...
Ochang, Ernest Afu
2013-01-01
In resource limited settings, the appropriation of scarce resources during research efforts can be daunting. Sourcing for disposable plastic bacteriological loops for manipulating M. tuberculosis had been eating into the research budget. In an attempt to reduce cost, an alternative and more cost effective way of obtaining autoclavable bacteriologic inoculation loops from used materials in the laboratory was employed. Autoclave resistant loops were prepared from polypropylene automatic pipette tips and platinum wires from electric stoves. The loop volume, when desired, was calculated using a simple mathematical equation after several passes in weighted water. Laboratories in resource poor settings could also save on inoculating loops by adopting such pragmatic approaches using recycled materials.
LMFBR with booster pump in pumping loop
International Nuclear Information System (INIS)
Rubinstein, H.J.
1975-01-01
A loop coolant circulation system is described for a liquid metal fast breeder reactor (LMFBR) utilizing a low head, high specific speed booster pump in the hot leg of the coolant loop with the main pump located in the cold leg of the loop, thereby providing the advantages of operating the main pump in the hot leg with the reliability of cold leg pump operation
Impaired standing balance: The clinical need for closing the loop
Pasma, J.H.; Pasma, Jantsje; Engelhart, Denise; Schouten, Alfred Christiaan; van der Kooij, Herman; Maier, A.B.; Meskers, C.G.M.
2014-01-01
Impaired balance may limit mobility and daily activities, and plays a key role in the elderly falling. Maintaining balance requires a concerted action of the sensory, nervous and motor systems, whereby cause and effect mutually affect each other within a closed loop. Aforementioned systems and their
Impaired Standing Balance: the Clinical Need for Closing the Loop
Pasma, J.H.; Engelhart, D.; Schouten, A.C.; van der Kooij, H.; Maier, A.B.; Meskers, C.G.M.
2014-01-01
Impaired balance may limit mobility and daily activities, and plays a key role in the elderly falling. Maintaining balance requires a concerted action of the sensory, nervous and motor systems, whereby cause and effect mutually affect each other within a closed loop. Aforementioned systems and their
Standing Slow MHD Waves in Radiatively Cooling Coronal Loops ...
Indian Academy of Sciences (India)
the individual and combined effects of radiation and thermal conduction are studied by displaying the analytical solution numerically. Our discussions and conclusions are presented in Section 5. 2. The model and governing equations. We model a straight coronal loop, in which the magnetic field is uniform and in.
Loop Growth and Point-Defect Profiles during HVEM Irradiation
DEFF Research Database (Denmark)
Leffers, Torben; Singh, Bachu Narain
1979-01-01
The point-defect profile in a thin foil is included in the model for the growth of dislocation loops during HVEM irradiation suggested by Kiritani, Yoshida, Takata, and Maehara, and the possible effect of divacancies is discussed. It is found that there is a fairly wide transition range between...
Ground Loop Impedance of Long EHV Cable Lines
DEFF Research Database (Denmark)
Ohno, Teruo; Bak, Claus Leth; Sørensen, Thomas K.
2012-01-01
in literature. Through the calculation of the ground loop impedance for cable lines, it has been found that, for long EHV cable lines, the reliable operation of the ground distance relay is possible with a typical relay setting. Effects of parameters, such as substation grounding, cable layouts...
Energy Technology Data Exchange (ETDEWEB)
Rubel, A.; Zhang, Y.; Liu, K.; Neathery, J. [University of Kentucky, Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY (United States)
2011-03-15
The application of Chemical Looping Combustion (CLC) to solid fuels is being investigated at the University of Kentucky, Center for Applied Energy Research (CAER) with the aim of the development of a Pressurized Chemical Looping Combustion/Gasification (PCLC/G) process for the generation of electricity from coal. One important aspect of the CLC of solid fuel is the understanding of the effect of ash on the reactivity of Oxygen Carriers (OCs). The effect of ash on the redox capabilities of two different iron oxide OCs and on their ability to oxidize coal char was studied. To determine the effect of ash on the reactivity and recycle of the OCs through multiple redox cycles, fly ash from a coal-fired power plant was used. These experiments were performed in a TGMS system using 500 mg of ash/OC mixtures containing different ash concentrations up to 75%. The reducing gas was composed of 10% H{sub 2}, 15% CO, 20% CO{sub 2}, and a balance of Ar and the oxidizing gas was 20% O{sub 2} in Ar. Oxidation/reductions were carried to near completion. The ash was found to contain OC activity related to inherent iron present in the ash confirmed by XRD. This resulted in increased weight gain/loss on oxidation/reduction. The rate of oxidation/reduction increased with ash concentration due to increased porosity of the OC/ash mixture and better access of the reactive gases to the OC target sites. The two OCs were then used to combust a beneficiated coal char in the TGMS with the only oxygen supplied by an iron oxide OC. The starting mixture was 10% char and 90% of one of two OCs studied. The spent material containing reduced OC and ash was re-oxidized and 10% more char was added for a second reduction of the OC and oxidation of the added char. This procedure was repeated for 5 cycles increasing the ash concentrations from 5 to 25% in the char/ash/OC mixture. Carbon removal was 92 to 97.8 and 97.3 to 99.7% for the two different iron oxide OCs tested. Ash was not detrimental to the
One-loop counterterms for the dimensional regularization of arbitrary Lagrangians
Pronin, P.; Stepanyantz, K.
1996-01-01
We present master formulas for the divergent part of the one-loop effective action for an arbitrary (both minimal and nonminimal) operators of any order in the 4-dimensional curved space. They can be considered as computer algorithms, because the one-loop calculations are then reduced to the simplest algebraic operations. Some test applications are considered by REDUCE analytical calculation system.
One-loop Correction of the Tachyon Action in Boundary Superstring Field Theory
Alishahiha, M.
2001-01-01
We compute one-loop correction to the string field theory. We would expect that the one-loop correction comes from the partition function of the two-dimensional worldsheet theory on the annulus. The annulus correction suggests that the genus expansion is, somehow, governed by the effective string
Soft Neutrosophic Loops and Their Generalization
Directory of Open Access Journals (Sweden)
Mumtaz Ali
2014-06-01
Full Text Available Soft set theory is a general mathematical tool for dealing with uncertain, fuzzy, not clearly defined objects. In this paper we introduced soft neutrosophic loop,soft neutosophic biloop, soft neutrosophic N -loop with the discuission of some of their characteristics. We also introduced a new type of soft neutrophic loop, the so called soft strong neutrosophic loop which is of pure neutrosophic character. This notion also found in all the other corresponding notions of soft neutrosophic thoery. We also given some of their properties of this newly born soft structure related to the strong part of neutrosophic theory.
Loop statistics in polymers in crowded environment
Haydukivska, K.; Blavatska, V.
2016-02-01
We analyze the probability to find a single loop in a long flexible polymer chain in disordered environment in d dimensions. The structural defects are considered to be correlated on large distances r according to a power law ˜r-a. Working within the frames of continuous chain model and applying the direct polymer renormalization scheme, we obtain the values of critical exponents governing the scaling of probabilities to find the loops of various positions along the chain as function of loops' length. Our results quantitatively reveal that the presence of structural defects in environment decreases the probability of loop formation in polymer macromolecules.
Numerical Contour Integration for Loop Integrals
Kurihara, Y.; Kaneko, T.
2005-01-01
A fully numerical method to calculate loop integrals, a numerical contour-integration method, is proposed. Loop integrals can be interpreted as a contour integral in a complex plane for an integrand with multi-poles in the plane. Stable and efficient numerical integrations an along appropriate contour can be performed for tensor integrals as well as for scalar ones appearing in loop calculations of the standard model. Examples of 3- and 4-point diagrams in 1-loop integrals and 2- and 3-point ...
Quantum chromodynamics as dynamics of loops
International Nuclear Information System (INIS)
Makeenko, Yu.; Migdal, A.A.
1980-01-01
The problem of a possibility of reformulating quantum chromodynamics (QCD) in terms of colourless composite fields instead of coloured quarks and gluons is considered. The role of such fields is played by the gauge invariant loop functionals. The Shwinger equations of motion is derived in the loop space which completely describe dynamics of the loop fields. New manifestly gauge invariant diagram technique in the loop space is developed. These diagrams reproduce asymptotic freedom in the ultraviolet range and are consistent with the confinement law in the infrared range
Vertically Polarized Omnidirectional Printed Slot Loop Antenna
DEFF Research Database (Denmark)
Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper
2015-01-01
A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....
Directory of Open Access Journals (Sweden)
Egor A Turovsky
Full Text Available This study investigated possible mechanisms of autoregulation of Ca(2+ signalling pathways in adipocytes responsible for Ca(2+ and NO oscillations and switching phenomena promoted by acetylcholine (ACh, norepinephrine (NE and atrial natriuretic peptide (ANP.Fluorescent microscopy was used to detect changes in Ca(2+ and NO in cultures of rodent white adipocytes. Agonists and inhibitors were applied to characterize the involvement of various enzymes and Ca(2+-channels in Ca(2+ signalling pathways.ACh activating M3-muscarinic receptors and Gβγ protein dependent phosphatidylinositol 3 kinase induces Ca(2+ and NO oscillations in adipocytes. At low concentrations of ACh which are insufficient to induce oscillations, NE or α1, α2-adrenergic agonists act by amplifying the effect of ACh to promote Ca(2+ oscillations or switching phenomena. SNAP, 8-Br-cAMP, NAD and ANP may also produce similar set of dynamic regimes. These regimes arise from activation of the ryanodine receptor (RyR with the implication of a long positive feedback loop (PFL: Ca(2+→NO→cGMP→cADPR→Ca(2+, which determines periodic or steady operation of a short PFL based on Ca(2+-induced Ca(2+ release via RyR by generating cADPR, a coagonist of Ca(2+ at the RyR. Interplay between these two loops may be responsible for the observed effects. Several other PFLs, based on activation of endothelial nitric oxide synthase or of protein kinase B by Ca(2+-dependent kinases, may reinforce functioning of main PFL and enhance reliability. All observed regimes are independent of operation of the phospholipase C/Ca(2+-signalling axis, which may be switched off due to negative feedback arising from phosphorylation of the inositol-3-phosphate receptor by protein kinase G.This study presents a kinetic model of Ca(2+-signalling system operating in adipocytes and integrating signals from various agonists, which describes it as multivariable multi feedback network with a family of nested positive
High-energy evolution to three loops
Caron-Huot, Simon; Herranen, Matti
2018-02-01
The Balitsky-Kovchegov equation describes the high-energy growth of gauge theory scattering amplitudes as well as nonlinear saturation effects which stop it. We obtain the three-loop corrections to the equation in planar N = 4 super Yang-Mills theory. Our method exploits a recently established equivalence with the physics of soft wide-angle radiation, so-called non-global logarithms, and thus yields at the same time the threeloop evolution equation for non-global logarithms. As a by-product of our analysis, we develop a Lorentz-covariant method to subtract infrared and collinear divergences in crosssection calculations in the planar limit. We compare our result in the linear regime with a recent prediction for the so-called Pomeron trajectory, and compare its collinear limit with predictions from the spectrum of twist-two operators.
Subleading soft graviton theorem for loop amplitudes
Sen, Ashoke
2017-11-01
Superstring field theory gives expressions for heterotic and type II string loop amplitudes that are free from ultraviolet and infrared divergences when the number of non-compact space-time dimensions is five or more. We prove the subleading soft graviton theorem in these theories to all orders in perturbation theory for S-matrix elements of arbitrary number of finite energy external states but only one external soft graviton. We also prove the leading soft graviton theorem for arbitrary number of finite energy external states and arbitrary number of soft gravitons. Since our analysis is based on general properties of one particle irreducible effective action, the results are valid in any theory of quantum gravity that gives finite result for the S-matrix order by order in perturbation theory without violating general coordinate invariance.
International Nuclear Information System (INIS)
Le-Prioux, Arno
2017-01-01
During irradiation in reactor, the microstructure of UO 2 changes and deteriorates, causing modifications of its physical and mechanical properties. The kinetic models used to describe these changes such as cluster dynamics (CRESCENDO calculation code) consider the main microstructural elements that are cavities and interstitial dislocation loops, and provide a rather rough description of the loop thermodynamics. In order to tackle this issue, this work has led to the development of a thermodynamic model of interstitial dislocation loops based on empirical potential calculations. The model considers two types of interstitial dislocation loops on two different size domains: Type 1: Dislocation loops similar to Frank partials in F.C.C. materials which are stable in the smaller size domain. Type 2: Perfect dislocation loops of Burgers vector (a/2)(110) stable in the larger size domain. The analytical formula used to compute the interstitial dislocation loop formation energies is the one for circular loops which has been modified in order to take into account the effects of the dislocation core, which are significant at smaller sizes. The parameters have been determined by empirical potential calculations of the formation energies of prismatic pure edge dislocation loops. The effect of the habit plane reorientation on the formation energies of perfect dislocation loops has been taken into account by a simple interpolation method. All the different types of loops seen during TEM observations are thus accounted for by the model. (author) [fr
Posner, Jonathan; Marsh, Rachel; Maia, Tiago V; Peterson, Bradley S; Gruber, Allison; Simpson, H Blair
2014-06-01
Cortico-striato-thalamo-cortical (CSTC) loops project from the cortex to the striatum, then from the striatum to the thalamus via the globus pallidus, and finally from the thalamus back to the cortex again. These loops have been implicated in Obsessive-Compulsive Disorder (OCD) with particular focus on the limbic CSTC loop, which encompasses the orbitofrontal and anterior cingulate cortices, as well as the ventral striatum. Resting state functional-connectivity MRI (rs-fcMRI) studies, which examine temporal correlations in neural activity across brain regions at rest, have examined CSTC loop connectivity in patients with OCD and suggest hyperconnectivity within these loops in medicated adults with OCD. We used rs-fcMRI to examine functional connectivity within CSTC loops in unmedicated adults with OCD (n = 23) versus healthy controls (HCs) (n = 20). Contrary to prior rs-fcMRI studies in OCD patients on medications that report hyperconnectivity in the limbic CSTC loop, we found that compared with HCs, unmedicated OCD participants had reduced connectivity within the limbic CSTC loop. Exploratory analyses revealed that reduced connectivity within the limbic CSTC loop correlated with OCD symptom severity in the OCD group. Our finding of limbic loop hypoconnectivity in unmedicted OCD patients highlights the potential confounding effects of antidepressants on connectivity measures and the value of future examinations of the effects of pharmacological and/or behavioral treatments on limbic CSTC loop connectivity. Copyright © 2013 Wiley Periodicals, Inc.
Baryon spectroscopy: symmetries, symmetry breaking and hadronic loops
International Nuclear Information System (INIS)
Zenczykowski, P.
1985-01-01
The problem of hadronic loop effects in baryon spectroscopy is thoroughly discussed. It is argued that such effects very likely constitute the dominant contribution to the observed splitting and mixing pattern of the (56,0 + ) and (70,1 - ) baryon multiplets. In particular, this dominance is demonstrated in the original Isgur-Karl-Koniuk model of baryons, in which hadronic loops are shown to provide an explanation for at least 2/3 of the observed size of splittings, both for the ground-state and excited baryons. The unitarity-induced mixing angles in the (70,1 - )-multiplet are also shown to be in good agreement with experiment. For the ground-state baryons the formula relating Σ-Λ and Δ-Ν mass differences - as originally derived by de Rujula, Georgi and Glashow from the single gluon exchange-is obtained from the hadronic loop effects as well. This (and other) results are derived after taking into account a complete set of symmetry-related hadronic loops. Consideration of such a complete set of symmetry-related processes is shown to be crucial in restoring proper symmetry properties of the calculated spectrum. 74 refs., 10 figs., 4 tabs. (author)
Dynamical behaviour of natural convection in closed loops
International Nuclear Information System (INIS)
Ehrhard, P.
1988-04-01
A one dimensional model is presented together with experiments, which describe the natural convective flow in closed loops heated at the bottom and cooled in the upper semicircle. Starting from a single loop, mechanical and thermal coupling with a second loop is discussed. The experiments and the theoretical model both concurrently demonstrate that the investigated natural convection is clearly influenced by non-linear effects. Beside the variety of stable steady flows there are extensive subcritical ranges of convective flow. In these parameter ranges subcritical instabilities of the steady state flow could occur in the presence of finite amplitude disturbances. However, the supercritical, global unstable range is characterized by chaotic histories of the variables of state. Non-symmetric heating generates an imperfect bifurcation out of the steady solution with zero velocity in the loop. This effect stabilizes the flow in the preferred direction. The flow in the opposite direction only remains stable in a small isolated interval of the heating parameter. Furthermore the calculations with the model equations demonstrate that a stable periodic behaviour of the flow is possible in a small parameter window. However, it has not been possible to verify this particular effect in the experiments conducted to date. (orig./GL) [de
CERN. Geneva
2016-01-01
Developing in python is fast. Computation, however, can often be another story. Or at least that is how it may seem. When working with arrays and numerical datasets one can subvert many of python’s computational limitations by utilizing numpy. Numpy is python’s standard matrix computation library. Many python users only use numpy to store and generate arrays, failing to utilize one of python’s most powerful computational tools. By leveraging numpy’s ufuncs, aggregation, broadcasting and slicing/masking/indexing functionality one can cut back on slow python loops and increase the speed of their programs by as much as 100x. This talk aims at teaching attendees how to use these tools through toy examples.
Comparing the thermal performance of horizontal slinky-loop and vertical slinky-loop heat exchangers
C.S.A. Chong; G. Gan; A. Verhoef; R.G. Garcia
2014-01-01
The heat pump market in the UK has grown rapidly over the last few years. Performance analyses of vertical ground-loop heat exchanger configurations have been widely carried out using both numerical modelling and experiments. However, research findings and design recommendations on horizontal slinky-loop and vertical slinky-loop heat exchangers are far fewer compared with those for vertical ground-loop heat exchanger configurations, especially where the long-term operation of the systems is c...
In-pile loop experiments in water chemistry and corrosion
International Nuclear Information System (INIS)
Kysela, J.; Jindrich, K.; Masarik, V.; Fric, Z.; Chotivka, V.; Hamerska, H.; Vsolak, R.; Erben, O.
1986-08-01
Methods and techniques used were as follows: (a) Method of polarizing resistance for remote monitoring of instantaneous rate of uniform corrosion. (b) Out-of-pile loop at the temperature 350 degC, pressure 19 MPa, circulation 20 kgs/h, testing time 1000 h. (c) High temperature electromagnetic filter with classical solenoid and ball matrix for high pressure filtration tests. (d) High pressure and high temperature in-pile water loop with coolant flow rate 10 000 kgs/h, neutron flux in active channel 7x10 13 n/cm 2 .s, 16 MPa, 330 degC. (e) Evaluation of experimental results by chemical and radiochemical analysis of coolant, corrosion products and corrosion layer on surface. The results of measurements carried out in loop facilities can be summarized into the following conclusions: (a) In-pile and out-of-pile loops are suitable means of investigating corrosion processes and mass transport in the nuclear power plant primary circuit. (b) In studying transport phenomena in the loop, it is necessary to consider the differences in geometry of the loop and the primary circuit, mainly the ratio of irradiated and non-irradiated surfaces and volumes. (c) In the experimental facility simulating the WWER-type nuclear power plant primary circuit, solid suspended particles of a chemical composition corresponding most frequently to magnetite or nickel ferrite, though with non-stoichiometric composition Me x 2+ Fe 3-x 3+ O 4 , were found. (d) Continuous filtration of water by means of an electromagnetic filter removing large particles of corrosion products leads to a decrease in radioactivity of the outer epitactic layer only. The effect of filtration on the inner topotactic layer is negligible
Loop quantum cosmology: a status report
Ashtekar, Abhay; Singh, Parampreet
2011-11-01
Loop quantum cosmology (LQC) is the result of applying principles of loop quantum gravity (LQG) to cosmological settings. The distinguishing feature of LQC is the prominent role played by the quantum geometry effects of LQG. In particular, quantum geometry creates a brand new repulsive force which is totally negligible at low spacetime curvature but rises very rapidly in the Planck regime, overwhelming the classical gravitational attraction. In cosmological models, while Einstein's equations hold to an excellent degree of approximation at low curvature, they undergo major modifications in the Planck regime: for matter satisfying the usual energy conditions, any time a curvature invariant grows to the Planck scale, quantum geometry effects dilute it, thereby resolving singularities of general relativity. Quantum geometry corrections become more sophisticated as the models become richer. In particular, in anisotropic models, there are significant changes in the dynamics of shear potentials which tame their singular behavior in striking contrast to older results on anisotropies in bouncing models. Once singularities are resolved, the conceptual paradigm of cosmology changes and one has to revisit many of the standard issues—e.g. the 'horizon problem'—from a new perspective. Such conceptual issues as well as potential observational consequences of the new Planck scale physics are being explored, especially within the inflationary paradigm. These considerations have given rise to a burst of activity in LQC in recent years, with contributions from quantum gravity experts, mathematical physicists and cosmologists. The goal of this review is to provide an overview of the current state of the art in LQC for three sets of audiences: young researchers interested in entering this area; the quantum gravity community in general and cosmologists who wish to apply LQC to probe modifications in the standard paradigm of the early universe. In this review, effort has been made to
Monitoring Digital Closed-Loop Feedback Systems
Katz, Richard; Kleyner, Igor
2011-01-01
A technique of monitoring digital closed-loop feedback systems has been conceived. The basic idea is to obtain information on the performances of closed-loop feedback circuits in such systems to aid in the determination of the functionality and integrity of the circuits and of performance margins. The need for this technique arises as follows: Some modern digital systems include feedback circuits that enable other circuits to perform with precision and are tolerant of changes in environment and the device s parameters. For example, in a precision timing circuit, it is desirable to make the circuit insensitive to variability as a result of the manufacture of circuit components and to the effects of temperature, voltage, radiation, and aging. However, such a design can also result in masking the indications of damaged and/or deteriorating components. The present technique incorporates test circuitry and associated engineering-telemetry circuitry into an embedded system to monitor the closed-loop feedback circuits, using spare gates that are often available in field programmable gate arrays (FPGAs). This technique enables a test engineer to determine the amount of performance margin in the system, detect out of family circuit performance, and determine one or more trend(s) in the performance of the system. In one system to which the technique has been applied, an ultra-stable oscillator is used as a reference for internal adjustment of 12 time-to-digital converters (TDCs). The feedback circuit produces a pulse-width-modulated signal that is fed as a control input into an amplifier, which controls the circuit s operating voltage. If the circuit s gates are determined to be operating too slowly or rapidly when their timing is compared with that of the reference signal, then the pulse width increases or decreases, respectively, thereby commanding the amplifier to increase or reduce, respectively, its output level, and "adjust" the speed of the circuits. The nominal
Simon, M. K.; Alem, W. K.
1978-01-01
Unbalanced quadriphase-shift-keying (QPSK) is an attractive means for transmitting two digital data streams which in general have different average powers, data rates, and data formats. Previous analyses of the tracking performance of Costas loop demodulators of unbalanced QPSK have accounted only for the filtering effect produced by the loop's two arm filters on the equivalent additive noise perturbing the loop. When the bandwidth of these filters is selected on the basis of the order of the data rate, as is typical of optimum Costas loop design, the filtering degradations of the data modulations themselves and the cross-modulation noise produced by their multiplication in the loop often cannot be neglected. The purpose of this paper is to incorporate these additional filtering effects into the analysis. Many of the results obtained herein are in the form of closed-form expressions which can easily be evaluated numerically for design and performance prediction purposes.
Fathallah-Shaykh, Hassan M; Bona, Jerry L; Kadener, Sebastian
2009-11-04
Eukaryotic circadian clocks include interconnected positive and negative feedback loops. The clock-cycle dimer (CLK-CYC) and its homolog, CLK-BMAL1, are key transcriptional activators of central components of the Drosophila and mammalian circadian networks, respectively. In Drosophila, negative loops include period-timeless and vrille; positive loops include par domain protein 1. Clockwork orange (CWO) is a recently discovered negative transcription factor with unusual effects on period, timeless, vrille, and par domain protein 1. To understand the actions of this protein, we introduced a new system of ordinary differential equations to model regulatory networks. The model is faithful in the sense that it replicates biological observations. CWO loop actions elevate CLK-CYC; the transcription of direct targets responds by integrating opposing signals from CWO and CLK-CYC. Loop regulation and integration of opposite transcriptional signals appear to be central mechanisms as they also explain paradoxical effects of period gain-of-function and null mutations.
International Nuclear Information System (INIS)
Dillistone, M.J.
1989-08-01
RELAP5/MOD2 predictions of countercurrent flow limitation in the UPTF hot leg separate effects Test (test 11) are compared with the experimental data. The code underestimates, by a factor of more than three, the gas flow necessary to prevent liquid runback from the steam generator, and this is shown to be due to an oversimplified flow-regime map which does not allow the possibility of stratified flow in the hot leg riser. The predicted countercurrent flow is also shown to depend, wrongly, on the depth of liquid in the steam generator plenum. The same test is also modelled using a version of the code in which stratified flow in the riser is made possible. The gas flow needed to prevent liquid runback is then predicted quite well, but at all lower gas flows the code predicts that the flow is completely unrestricted - i.e. liquid flows between full flow and zero flow are not predicted. This is shown to happen because the code cannot calculate correctly the liquid level in the hot leg, mainly because of a numerical effect of upwind donoring in the momentum flux terms of the code's basic equations. It is also shown that the code cannot model the considerable effect of the ECCS injection pipe (which runs inside the hot leg) on the liquid level. (author)
Crone, Julia Sophia; Lutkenhoff, Evan Scott; Bio, Branden Joseph; Laureys, Steven; Monti, Martin Max
2017-04-01
In recent years, a number of brain regions and connectivity patterns have been proposed to be crucial for loss and recovery of consciousness but have not been compared in detail. In a 3 T resting-state functional magnetic resonance imaging paradigm, we test the plausibility of these different neuronal models derived from theoretical and empirical knowledge. Specifically, we assess the fit of each model to the dynamic change in effective connectivity between specific cortical and subcortical regions at different consecutive levels of propofol-induced sedation by employing spectral dynamic causal modeling. Surprisingly, our findings indicate that proposed models of impaired consciousness do not fit the observed patterns of effective connectivity. Rather, the data show that loss of consciousness, at least in the context of propofol-induced sedation, is marked by a breakdown of corticopetal projections from the globus pallidus. Effective connectivity between the globus pallidus and the ventral posterior cingulate cortex, present during wakefulness, fades in the transition from lightly sedated to full loss of consciousness and returns gradually as consciousness recovers, thereby, demonstrating the dynamic shift in brain architecture of the posterior cingulate "hub" during changing states of consciousness. These findings highlight the functional role of a previously underappreciated direct pallido-cortical connectivity in supporting consciousness. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Understanding the Hysteresis Loop Conundrum in Pharmacokinetic / Pharmacodynamic Relationships
Louizos, Christopher; Yáñez, Jaime A.; Forrest, Laird; Davies, Neal M.
2015-01-01
Hysteresis loops are phenomena that sometimes are encountered in the analysis of pharmacokinetic and pharmacodynamic relationships spanning from pre-clinical to clinical studies. When hysteresis occurs it provides insight into the complexity of drug action and disposition that can be encountered. Hysteresis loops suggest that the relationship between drug concentration and the effect being measured is not a simple direct relationship, but may have an inherent time delay and disequilibrium, which may be the result of metabolites, the consequence of changes in pharmacodynamics or the use of a non-specific assay or may involve an indirect relationship. Counter-clockwise hysteresis has been generally defined as the process in which effect can increase with time for a given drug concentration, while in the case of clockwise hysteresis the measured effect decreases with time for a given drug concentration. Hysteresis loops can occur as a consequence of a number of different pharmacokinetic and pharmacodynamic mechanisms including tolerance, distributional delay, feedback regulation, input and output rate changes, agonistic or antagonistic active metabolites, uptake into active site, slow receptor kinetics, delayed or modified activity, time-dependent protein binding and the use of racemic drugs among other factors. In this review, each of these various causes of hysteresis loops are discussed, with incorporation of relevant examples of drugs demonstrating these relationships for illustrative purposes. Furthermore, the effect that pharmaceutical formulation has on the occurrence and potential change in direction of the hysteresis loop, and the major pharmacokinetic / pharmacodynamic modeling approaches utilized to collapse and model hysteresis are detailed. PMID:24735761
DEFF Research Database (Denmark)
Papaleo, Elena; Casiraghi, Nicola; Arrigoni, Alberto
2012-01-01
, and influencing the ultimate fate of the substrates. Several E2s are characterized by an extended acidic insertion in loop 7 (L7), which if mutated is known to impair the proper E2-related functions. In the present contribution, we show that acidic loop is a conserved ancestral motif in E2s, relying...
Holonomy loops, spectral triples and quantum gravity
DEFF Research Database (Denmark)
Johannes, Aastrup; Grimstrup, Jesper Møller; Nest, Ryszard
2009-01-01
We review the motivation, construction and physical interpretation of a semi-finite spectral triple obtained through a rearrangement of central elements of loop quantum gravity. The triple is based on a countable set of oriented graphs and the algebra consists of generalized holonomy loops...
Wit, B. de; Grisaru, M. T.; Nieuwenhuizen, P. van
1993-01-01
We study perturbatively the (conformal) WZNW model. At one loop we compute one-particle irreducible two- and three-point current correlation functions, both in the conventional version and in the classically equivalent, chiral, nonlocal, induced version of the model. At two loops we compute the
Newtonian gravity in loop quantum gravity
Smolin, Lee
2010-01-01
We apply a recent argument of Verlinde to loop quantum gravity, to conclude that Newton's law of gravity emerges in an appropriate limit and setting. This is possible because the relationship between area and entropy is realized in loop quantum gravity when boundaries are imposed on a quantum spacetime.
One-loop matching and running with covariant derivative expansion
Henning, Brian; Lu, Xiaochuan; Murayama, Hitoshi
2018-01-01
We develop tools for performing effective field theory (EFT) calculations in a manifestly gauge-covariant fashion. We clarify how functional methods account for one-loop diagrams resulting from the exchange of both heavy and light fields, as some confusion has recently arisen in the literature. To efficiently evaluate functional traces containing these "mixed" one-loop terms, we develop a new covariant derivative expansion (CDE) technique that is capable of evaluating a much wider class of traces than previous methods. The technique is detailed in an appendix, so that it can be read independently from the rest of this work. We review the well-known matching procedure to one-loop order with functional methods. What we add to this story is showing how to isolate one-loop terms coming from diagrams involving only heavy propagators from diagrams with mixed heavy and light propagators. This is done using a non-local effective action, which physically connects to the notion of "integrating out" heavy fields. Lastly, we show how to use a CDE to do running analyses in EFTs, i.e. to obtain the anomalous dimension matrix. We demonstrate the methodologies by several explicit example calculations.
More on soft theorems: Trees, loops, and strings
Bianchi, Massimo; He, Song; Huang, Yu-tin; Wen, Congkao
2015-09-01
We study soft theorems in a broader context, their universality in effective field theories and string theory, as well as continue the analysis of their fate at loop level. In effective field theories with F3 and R3 interactions, the soft theorems are not modified. However, for gravity theories with R2ϕ interactions, the sub-subleading order soft graviton theorem, which is beyond what is implied by the extended Bondi, van der Burg, Metzner, and Sachs symmetry, requires modifications at tree level for nonsupersymmetric theories and at loop level for N ≤4 supergravity due to anomalies. For open and closed superstrings at finite α', via explicit calculation for lower-point examples as well as world sheet operator product expansion analysis for arbitrary multiplicity, we show that scattering amplitudes satisfy the same soft theorem as their field-theory counterpart. This is no longer true for closed bosonic or heterotic strings due to the presence of R2ϕ interactions. We also consider loop corrections to gauge theories in the planar limit, where we show that tree-level soft gluon theorems are respected at the integrand level for 1 ≤N ≤4 SYM. Finally, we discuss the fate of soft theorems for finite loop amplitudes in pure Yang-Mills theory and gravity.
Study of loop-loop and loop-edge dislocation interactions in bcc iron
DEFF Research Database (Denmark)
Osetsky, Y.N.; Bacon, D.J.; Gao, F.
2000-01-01
Recent theoretical calculations and atomistic computer simulations have shown that one-dimensional glissile clusters of self-interstitial atoms (SIAs) play an important role in the evolution of microstructure in metals and alloys under cascade damage conditions. Recently, it has been proposed...... that the evolution of heterogeneities such as dislocation decoration and rafts has serious impacts on the mechanical properties on neutron-irradiated metals. In the present work, atomic-scale computer modelling (ASCM) has been applied to study the mechanisms for the formation of such microstructure in bcc iron....... It is shown that glissile clusters with parallel Burgers vectors interact strongly and can form extended immobile complexes, i.e., rafts. Similar attractive interaction exists between dislocation loops and an edge dislocation. These two mechanisms may be responsible for the formation of extended complexes...
International Nuclear Information System (INIS)
Cabrera, B.; Gardner, R.; King, R.
1985-01-01
We have calculated the response of the existing one- and three-loop superconductive magnetic-monopole detectors to an isotropic distribution of monopole trajectories passing through the detectors. The effective sensing area of the three-loop detector is shown to be 476 cm 2 for events greater than 0.1Phi 0 (Phi 0 = hc/2e) in at least two of the three loops. These calculations include the effects of the cylindrical superconducting shields surrounding the loops. First the interior magnetic-field distribution within the cylindrical shield is found for a doubly quantized vortex located in the shield wall. Next the coupling of this field to each superconducting loop is computed as a function of the position of the vortex relative to the loop. Then the current change induced in the loops is found for each monopole trajectory by combining the direct coupling to the entering and exiting cylinder wall vortices. The one- and three-loop sensing-area distribution functions are then found using a Monte Carlo technique on a large number of isotropically distributed trajectories
Hydraulic loop: practices using open control systems
International Nuclear Information System (INIS)
Carrasco, J.A.; Alonso, L.; Sanchez, F.
1998-01-01
The Tecnatom Hydraulic Loop is a dynamic training platform. It has been designed with the purpose of improving the work in teams. With this system, the student can obtain a full scope vision of a system. The hydraulic Loop is a part of the Tecnatom Maintenance Centre. The first objective of the hydraulic Loop is the instruction in components, process and process control using open control system. All the personal of an electric power plant can be trained in the Hydraulic Loop with specific courses. The development of a dynamic tool for tests previous to plant installations has been an additional objective of the Hydraulic Loop. The use of this platform is complementary to the use of full-scope simulators in order to debug and to analyse advanced control strategies. (Author)
The Wilson loop and some applications
International Nuclear Information System (INIS)
Bezerra, V.B.
1983-04-01
A simple relation between the classical Wilson loop and the angular deviation in the parallel displacement is found. An example of potentials which give field copies and which suplly the same classical Wilson loop for a particular trajectory is exhibited. The asymptotic behaviour of the Wilson loop for the BPST instanton and the meron, is discussed. By using the dimensional regularization technique to calculate the second order term of the quantum Wilson loop, the influence of geometrical factors for the residue in the pole due to contact points, cuspides and intersections, in function of the space-time ν, is investigated. Charge renormalization in Quantum electrodynamics is finally calculated by using the quantum Wilson loop. (L.C.) [pt
The Wilson loop and some applications
International Nuclear Information System (INIS)
Bezerra, V.B.
1983-01-01
A simple relation between the classical Wilson loop and the angular deviation in the parallel shift is found. An example of potential which given field copies and which give the same classical Wilson loop for a given trajectory is exchibited. Afterwards, the asymptotic behaviour of the Wilson loop for the BPST instanton and meron is discussed. Using the dimensional regularization technique to calculate the second order term of Quantum Wilson loop, the influence of geometrical factors for the residue in the polo due to contact points, cusp and intersections, in function of the upsilon dimension of the space-time is investigated. Finally, the charge renormalization in Quantum Electrodynamics using Quantum Wilson loop is calculated. (L.C.) [pt
Osmotic mechanism of the loop extrusion process
Yamamoto, Tetsuya; Schiessel, Helmut
2017-09-01
The loop extrusion theory assumes that protein factors, such as cohesin rings, act as molecular motors that extrude chromatin loops. However, recent single molecule experiments have shown that cohesin does not show motor activity. To predict the physical mechanism involved in loop extrusion, we here theoretically analyze the dynamics of cohesin rings on a loop, where a cohesin loader is in the middle and unloaders at the ends. Cohesin monomers bind to the loader rather frequently and cohesin dimers bind to this site only occasionally. Our theory predicts that a cohesin dimer extrudes loops by the osmotic pressure of cohesin monomers on the chromatin fiber between the two connected rings. With this mechanism, the frequency of the interactions between chromatin segments depends on the loading and unloading rates of dimers at the corresponding sites.
Directory of Open Access Journals (Sweden)
Ke Tang
2014-04-01
Full Text Available Loops in proteins are flexible regions connecting regular secondary structures. They are often involved in protein functions through interacting with other molecules. The irregularity and flexibility of loops make their structures difficult to determine experimentally and challenging to model computationally. Conformation sampling and energy evaluation are the two key components in loop modeling. We have developed a new method for loop conformation sampling and prediction based on a chain growth sequential Monte Carlo sampling strategy, called Distance-guided Sequential chain-Growth Monte Carlo (DISGRO. With an energy function designed specifically for loops, our method can efficiently generate high quality loop conformations with low energy that are enriched with near-native loop structures. The average minimum global backbone RMSD for 1,000 conformations of 12-residue loops is 1:53 A° , with a lowest energy RMSD of 2:99 A° , and an average ensembleRMSD of 5:23 A° . A novel geometric criterion is applied to speed up calculations. The computational cost of generating 1,000 conformations for each of the x loops in a benchmark dataset is only about 10 cpu minutes for 12-residue loops, compared to ca 180 cpu minutes using the FALCm method. Test results on benchmark datasets show that DISGRO performs comparably or better than previous successful methods, while requiring far less computing time. DISGRO is especially effective in modeling longer loops (10-17 residues.
Vertically Polarized Omnidirectional Printed Slot Loop AntennaPrinted Slot Loop Antenna (invited)
DEFF Research Database (Denmark)
Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren Helstrup; Thaysen, Jesper
2015-01-01
A novel verticall A novel vertically polarized dpolarize , omnidirection omnidirectional l , printed slot loop antenna h sprinted slot loop antenna has been designed, simulated, fabricated, and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform...... and in-phase fields in the slot in order to obtain an omnidirectional radiation pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due...
A kinematic view of loop closure.
Coutsias, Evangelos A; Seok, Chaok; Jacobson, Matthew P; Dill, Ken A
2004-03-01
We consider the problem of loop closure, i.e., of finding the ensemble of possible backbone structures of a chain segment of a protein molecule that is geometrically consistent with preceding and following parts of the chain whose structures are given. We reduce this problem of determining the loop conformations of six torsions to finding the real roots of a 16th degree polynomial in one variable, based on the robotics literature on the kinematics of the equivalent rotator linkage in the most general case of oblique rotators. We provide a simple intuitive view and derivation of the polynomial for the case in which each of the three pair of torsional axes has a common point. Our method generalizes previous work on analytical loop closure in that the torsion angles need not be consecutive, and any rigid intervening segments are allowed between the free torsions. Our approach also allows for a small degree of flexibility in the bond angles and the peptide torsion angles; this substantially enlarges the space of solvable configurations as is demonstrated by an application of the method to the modeling of cyclic pentapeptides. We give further applications to two important problems. First, we show that this analytical loop closure algorithm can be efficiently combined with an existing loop-construction algorithm to sample loops longer than three residues. Second, we show that Monte Carlo minimization is made severalfold more efficient by employing the local moves generated by the loop closure algorithm, when applied to the global minimization of an eight-residue loop. Our loop closure algorithm is freely available at http://dillgroup. ucsf.edu/loop_closure/. Copyright 2004 Wiley Periodicals, Inc. J Comput Chem 25: 510-528, 2004
Thermodynamic examination of 1- to 5-nt purine bulge loops in RNA and DNA constructs.
Strom, Shane; Shiskova, Evgenia; Hahm, Yaeeun; Grover, Neena
2015-07-01
Bulge loops are common features of RNA structures that are involved in the formation of RNA tertiary structures and are often sites for interactions with proteins and ions. Minimal thermodynamic data currently exist on the bulge size and sequence effects. Using thermal denaturation methods, thermodynamic properties of 1- to 5-nt adenine and guanine bulge loop constructs were examined in 10 mM MgCl(2) or 1 M KCl. The [Formula: see text] loop parameters for 1- to 5-nt purine bulge loops in RNA constructs were between 3.07 and 5.31 kcal/mol in 1 M KCl buffer. In 10 mM magnesium ions, the ΔΔG° values relative to 1 M KCl were 0.47-2.06 kcal/mol more favorable for the RNA bulge loops. The [Formula: see text] loop parameters for 1- to 5-nt purine bulge loops in DNA constructs were between 4.54 and 5.89 kcal/mol. Only 4- and 5-nt guanine constructs showed significant change in stability for the DNA constructs in magnesium ions. A linear correlation is seen between the size of the bulge loop and its stability. New prediction models are proposed for 1- to 5-nt purine bulge loops in RNA and DNA in 1 M KCl. We show that a significant stabilization is seen for small bulge loops in RNA in the presence of magnesium ions. A prediction model is also proposed for 1- to 5-nt purine bulge loop RNA constructs in 10 mM magnesium chloride. © 2015 Strom et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.
HCl removal using cycled carbide slag from calcium looping cycles
International Nuclear Information System (INIS)
Xie, Xin; Li, Yingjie; Wang, Wenjing; Shi, Lei
2014-01-01
Highlights: • Cycled carbide slag from calcium looping cycles is used to remove HCl. • The optimum temperature for HCl removal of cycled carbide slag is 700 °C. • The presence of CO 2 restrains HCl removal of cycled carbide slag. • CO 2 capture conditions have important effects on HCl removal of cycled carbide slag. • HCl removal capacity of carbide slag drops with cycle number rising from 1 to 50. - Abstract: The carbide slag is an industrial waste from chlor-alkali plants, which can be used to capture CO 2 in the calcium looping cycles, i.e. carbonation/calcination cycles. In this work, the cycled carbide slag from the calcium looping cycles for CO 2 capture was proposed to remove HCl in the flue gas from the biomass-fired and RDFs-fired boilers. The effects of chlorination temperature, HCl concentration, particle size, presence of CO 2 , presence of O 2 , cycle number and CO 2 capture conditions in calcium looping cycles on the HCl removal behavior of the carbide slag experienced carbonation/calcination cycles were investigated in a triple fixed-bed reactor. The chlorination product of the cycled carbide slag from the calcium looping after absorbing HCl is not CaCl 2 but CaClOH. The optimum temperature for HCl removal of the cycled carbide slag from the carbonation/calcination cycles is 700 °C. The chlorination conversion of the cycled carbide slag increases with increasing the HCl concentration. The cycled carbide slag with larger particle size exhibits a lower chlorination conversion. The presence of CO 2 decreases the chlorination conversions of the cycled carbide slag and the presence of O 2 has a trifling impact. The chlorination conversion of the carbide slag experienced 1 carbonation/calcination cycle is higher than that of the uncycled calcined sorbent. As the number of carbonation/calcination cycles increases from 1 to 50, the chlorination conversion of carbide slag drops gradually. The high calcination temperature and high CO 2
International Nuclear Information System (INIS)
Shopsky, W.E.
1977-01-01
The Emergency Core Cooling System (ECCS) is a Safeguards System designed to cool the core in the unlikely event of a Loss-of-Coolant Accident (LOCA) in the primary reactor coolant system as well as to provide additional shutdown capability following a steam break accident. The system is designed for a high reliability of providing emergency coolant and shutdown reactivity to the core for all anticipated occurrences of such accidents. The ECCS by performing its intended function assures that fuel and clad damage is minimized during accident conditions thus reducing release of fission products from the fuel. The ECCS is designed to perform its function despite sustaining a single failure by the judicious use of equipment and flow path redundancy within and outside the containment structure. By the use of an analytic tool, a Failure Mode and Effects Analysis (FMEA), it is shown that the ECCS is in compliance with the Single Failure Criterion established for active failures of fluid systems during short and long term cooling of the reactor core following a LOCA or steam break accident. An analysis was also performed with regards to passive failure of ECCS components during long-term cooling of the core following an accident. The design of the ECCS was verified as being able to tolerate a single passive failure during long-term cooling of the reactor core following an accident. The FMEA conducted qualitatively demonstrates the reliability of the ECCS (concerning active components) to perform its intended safety function
Closed loop models for analyzing engineering requirements for simulators
Baron, S.; Muralidharan, R.; Kleinman, D.
1980-01-01
A closed loop analytic model, incorporating a model for the human pilot, (namely, the optimal control model) that would allow certain simulation design tradeoffs to be evaluated quantitatively was developed. This model was applied to a realistic flight control problem. The resulting model is used to analyze both overall simulation effects and the effects of individual elements. The results show that, as compared to an ideal continuous simulation, the discrete simulation can result in significant performance and/or workload penalties.
Loops in hierarchical channel networks
Katifori, Eleni; Magnasco, Marcelo
2012-02-01
Nature provides us with many examples of planar distribution and structural networks having dense sets of closed loops. An archetype of this form of network organization is the vasculature of dicotyledonous leaves, which showcases a hierarchically-nested architecture. Although a number of methods have been proposed to measure aspects of the structure of such networks, a robust metric to quantify their hierarchical organization is still lacking. We present an algorithmic framework that allows mapping loopy networks to binary trees, preserving in the connectivity of the trees the architecture of the original graph. We apply this framework to investigate computer generated and natural graphs extracted from digitized images of dicotyledonous leaves and animal vasculature. We calculate various metrics on the corresponding trees and discuss the relationship of these quantities to the architectural organization of the original graphs. This algorithmic framework decouples the geometric information from the metric topology (connectivity and edge weight) and it ultimately allows us to perform a quantitative statistical comparison between predictions of theoretical models and naturally occurring loopy graphs.
TS LOOP ALCOVE VENTILATION ANALYSIS
International Nuclear Information System (INIS)
T.M. Lahnalampi
2000-01-01
The scope of this analysis is to examine the existing, constructor installed, physical ventilation installations located in each of the Exploratory Studies Facility (ESF) Topopah Springs (TS) Loop Alcoves No.1, No.2, No.3, No.4, No.6, and No.7. Alcove No.5 is excluded from the scope of this analysis since it is an A/E design system. Each ventilation installation will be analyzed for the purpose of determining if requirements for acceptance into the A/E design technical baseline have been met. The ventilation installations will be evaluated using Occupational Safety and Health Administration (OSHA) standards and Exploratory Studies Facility Design Requirements (ESFDR) (YMP 1997) requirements. The end product will be a technical analysis that will define ventilation installation compliance issues, any outstanding field changes, and use-as-is design deviations that are required to bring the ventilation installations into compliance with requirements for acceptance into the A/E design technical baseline. The analysis will provide guidance for alcove ventilation component design modifications to be developed to correct any deficient components that do not meet minimum requirements and standards
Nonlinear robust dual-loop control for electro-hydraulic load simulator.
Wang, Chengwen; Jiao, Zongxia; Quan, Long
2015-11-01
This paper investigates on the high performance torque control of electro-hydraulic load simulator (EHLS). In order to suppress actuator's motion disturbance, a nonlinear robust dual-loop control scheme is developed, which consists of a open-loop nonlinear velocity feed-forward compensator and a closed-loop nonlinear deterministic robust torque controller. The main function of the open-loop compensator is to decouple actuator's active motion disturbance, whereas the torque loop controller aims at guaranteeing the dynamics performance of tracking torque reference. Besides actuator's motion disturbance, both the nonlinearity characteristics and friction problem of the EHLS system are taken into consideration in this paper. The effectiveness of the developed method are verified through comparative co-simulations and experiments. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.
Dynamic Looping of a Free-Draining Polymer
Energy Technology Data Exchange (ETDEWEB)
Ye, Felix X. -F.; Stinis, Panos; Qian, Hong
2018-01-01
In order to investigate analytically the looping time of a free-draining polymer (Rouse model), we revisit the celebrated Wilemski-Fixman (WF) theory. The WF theory introduces a sink term in the Fokker-Planck equation to account for the complicated boundary condition satisfied by the looping effect. We use perturbation methods to make theoretical predictions of the looping time for two popular choices for the sink, namely the Delta and Heaviside sinks. For both types of sink, we show that under the condition of small capture radius (compared to the Kuhn length), WF can produce all known analytical and asymptotic results obtained by other means. This includes the mixed scaling regime which combines Doi's N2 scaling and Szabo, Schulten & Schulten's N√N/ɑ scaling. In addition, again for the case of small capture radius, we find an extra term in the analytical expression for the looping time which has not appeared previously in the literature. Numerical results obtained through Monte Carlo simulations corroborate the theoretical findings. The mathematical constructions developed here can be applied to other diffusion limited catalytically activated chemical reactions.
Design validation and performance of closed loop gas recirculation system
Kalmani, S. D.; Joshi, A. V.; Majumder, G.; Mondal, N. K.; Shinde, R. R.
2016-11-01
A pilot experimental set up of the India Based Neutrino Observatory's ICAL detector has been operational for the last 4 years at TIFR, Mumbai. Twelve glass RPC detectors of size 2 × 2 m2, with a gas gap of 2 mm are under test in a closed loop gas recirculation system. These RPCs are continuously purged individually, with a gas mixture of R134a (C2H2F4), isobutane (iC4H10) and sulphur hexafluoride (SF6) at a steady rate of 360 ml/h to maintain about one volume change a day. To economize gas mixture consumption and to reduce the effluents from being released into the atmosphere, a closed loop system has been designed, fabricated and installed at TIFR. The pressure and flow rate in the loop is controlled by mass flow controllers and pressure transmitters. The performance and integrity of RPCs in the pilot experimental set up is being monitored to assess the effect of periodic fluctuation and transients in atmospheric pressure and temperature, room pressure variation, flow pulsations, uniformity of gas distribution and power failures. The capability of closed loop gas recirculation system to respond to these changes is also studied. The conclusions from the above experiment are presented. The validations of the first design considerations and subsequent modifications have provided improved guidelines for the future design of the engineering module gas system.
Response of the primary piping loop to an HCDA
International Nuclear Information System (INIS)
Chang, Y.W.; Moneim, M.T.A.; Wang, C.Y.; Gvildys, J.
1975-01-01
The paper describes a method for analyzing the response of the primary piping loop that consists of straight pipes, elbows, and other components connected in series and subject to hypothetical core disruptive accident (HCDA) loads at both ends of the loop. The complete hydrodynamic equations in two-dimensions, that include both the nonlinear convective and viscous dissipation terms are used for the fluid dynamics together with the implicit ICE technique. The external walls of the pipes and components are treated as thin shells in which the analysis accounts for the membrane and bending strength of the wall, elastic-plastic material behavior, as well as large deformation under the effect of transient loading conditions. In the straight pipes, the flow is assumed to be axisymmetric; in the elbow regions, the two dimensions considered are the r and theta directions. The flow in the other components is also assumed to be axisymmetric; the components are modeled as a circular cylinder, in which the radius of the cylinder can be varied to conform with the outside shape of the component and the flow area inside can be changed independently from the outside shape. However, they must remain axially symmetric. The method is applied to a piping loop which consists of six elastic-plastic pipes and five rigid elbows connected in series and subjected to pressure pulses at both ends of the loop