In this study, we investigate the impact of the dynamic behavior of photovoltaic (PV) power generation systems on short-term voltage stability of the transmission system. First, the impact of the ...fault ride-through capability of a PV model is studied by setting several recovery speeds of the active current output when the operation of the PV system is interrupted because of a voltage sag. The results are analyzed by using transient P-V curves and a stability boundary, which has been proposed in our previous research. Further, we show that the installation of PVs severely impairs the short-term voltage stability if the PVs shut off after a voltage sag, and its recovery speed is low. Next, two countermeasures to control short-term voltage instability phenomena are tested. One is the operation of the PV system at a leading power factor in the normal state, and the other is the dynamic reactive power control by the inverters of the PV system after a voltage sag. Numerical examples are carried out for a one-load infinite-bus power system and a five-machine five-load power system. The results show that these countermeasures can play a substantial role in preventing the voltage instability phenomena caused when a PV system is suddenly interrupted because of a fault.
Short-term voltage stability is one of the issues of concern for power system operations. As dispersed power generation is connected to middle- and low-voltage transmission networks, the development ...of analytical methods will become more important. This paper describes a stability boundary line in the P-V plane of the load bus for the analysis of short-term voltage stability. By comparing the operating point of the load with the boundary line, we can visually determine the acceleration or deceleration state of the induction motor, thereby clearly explaining the short-term voltage instability phenomena. In addition, the idea of the stability boundary is applied to voltage stability assessment and emergency controls such as reactive power compensation. Numerical simulations are carried out for a single-load infinite-bus system to explain the basic theory of the proposed method and to provide examples of its application.
Gemcitabine plus cisplatin (GC) is the standard treatment of advanced biliary tract cancer (BTC); however, it causes nausea, vomiting, and anorexia, and requires hydration. Gemcitabine plus S-1 (GS) ...reportedly has equal to, or better, efficacy and an acceptable toxicity profile. We aimed to confirm the non-inferiority of GS to GC for patients with advanced/recurrent BTC in terms of overall survival (OS).
We undertook a phase III randomized trial in 33 institutions in Japan. Eligibility criteria included chemotherapy-naïve patients with recurrent or unresectable BTC, an Eastern Cooperative Oncology Group Performance Status of 0−1, and adequate organ function. The calculated sample size was 350 with a one-sided α of 5%, a power of 80%, and non-inferiority margin hazard ratio (HR) of 1.155. The primary end point was OS, while the secondary end points included progression-free survival (PFS), response rate (RR), adverse events (AEs), and clinically significant AEs defined as grade ≥2 fatigue, anorexia, nausea, vomiting, oral mucositis, or diarrhea.
Between May 2013 and March 2016, 354 patients were enrolled. GS was found to be non-inferior to GC median OS: 13.4months with GC and 15.1months with GS, HR, 0.945; 90% confidence interval (CI), 0.78–1.15; P=0.046 for non-inferiority. The median PFS was 5.8months with GC and 6.8months with GS (HR 0.86; 95% CI 0.70–1.07). The RR was 32.4% with GC and 29.8% with GS. Both treatments were generally well-tolerated. Clinically significant AEs were observed in 35.1% of patients in the GC arm and 29.9% in the GS arm.
GS, which does not require hydration, should be considered a new, convenient standard of care option for patients with advanced/recurrent BTC.
This trial has been registered with the UMIN Clinical Trials Registry (http://www.umin.ac.jp/ctr/index.htm), number UMIN000010667.
We describe the influence of environmental noise on Laser Interferometric Gravitational-Wave Observatory (LIGO) detectors in the sixth science run, from July 2009 to October 2010. We show results ...from experimental investigations testing the coupling level and mechanisms for acoustic, electromagnetic/magnetic and seismic noise to the instruments. We argue the sensors' importance for vetoes of false positive detections, report estimates of the noise sources' contributions to the detector background, and discuss the ways in which environmental coupling should be reduced in the LIGO upgrade, Advanced LIGO.
This study aimed to evaluate the effects of green tea on the pharmacokinetics and pharmacodynamics of the β‐blocker nadolol. Ten healthy volunteers received a single oral dose of 30 mg nadolol with ...green tea or water after repeated consumption of green tea (700 ml/day) or water for 14 days. Catechin concentrations in green tea and plasma were determined. Green tea markedly decreased the maximum plasma concentration (Cmax) and area under the plasma concentration–time curve (AUC0–48) of nadolol by 85.3% and 85.0%, respectively (P < 0.01), without altering renal clearance of nadolol. The effects of nadolol on systolic blood pressure were significantly reduced by green tea. 3H‐Nadolol uptake assays in human embryonic kidney 293 cells stably expressing the organic anion–transporting polypeptides OATP1A2 and OATP2B1 revealed that nadolol is a substrate of OATP1A2 (Michaelis constant (Km) = 84.3 μmol/l) but not of OATP2B1. Moreover, green tea significantly inhibited OATP1A2‐mediated nadolol uptake (half‐maximal inhibitory concentration, IC50 = 1.36%). These results suggest that green tea reduces plasma concentrations of nadolol possibly in part by inhibition of OATP1A2‐mediated uptake of nadolol in the intestine.
Clinical Pharmacology & Therapeutics (2014); 95 4, 432–438. doi:10.1038/clpt.2013.241
Interferometric gravitational-wave detectors are complex instruments comprised of a Michelson interferometer enhanced by multiple coupled cavities. Active feedback control is required to operate ...these instruments and keep the cavities locked on resonance. The optical response is highly nonlinear until a good operating point is reached. The linear operating range is between and 1% of a fringe for each degree of freedom. The resonance lock has to be achieved in all five degrees of freedom simultaneously, making the acquisition difficult. Furthermore, the cavity linewidth seen by the laser is only Hz, which is four orders of magnitude smaller than the linewidth of the free running laser. The arm length stabilization system is a new technique used for arm cavity locking in Advanced LIGO. Together with a modulation technique utilizing third harmonics to lock the central Michelson interferometer, the Advanced LIGO detector has been successfully locked and brought to an operating point where detecting gravitational-waves becomes feasible.
Abstract Experiments were done in urethane-anesthetized, barodenervated, male Wistar rats. Chemical stimulation of the hypothalamic paraventricular nucleus (PVN) by unilateral microinjections of N ...-methyl- d -aspartic acid (NMDA) elicited increases in mean arterial pressure (MAP) and greater splanchnic nerve activity (GSNA). The increases in the MAP and GSNA induced by chemical stimulation of the PVN were significantly exaggerated by bilateral microinjections of d (−)-2-amino-7-phosphono-heptanoic acid ( d -AP7) and 2,3-dioxo-6-nitro-1,2,3,4-tetrahydro-benzofquinoxaline-7-sulfonamide disodium (NBQX) (ionotropic glutamate receptor antagonists) into the medial subnucleus of the nucleus tractus solitarius (mNTS). These results were confirmed by single unit recordings; i.e. excitation of mNTS barosensitive neurons caused by chemical stimulation of the ipsilateral PVN was blocked by application of d -AP7 and NBQX to these neurons. Bilateral microinjections of d -AP7 and NBQX into the mNTS elicited pressor responses which were significantly attenuated by inhibition of PVN neurons by bilateral microinjections of muscimol. Unilateral microinjections of fluorogold into the mNTS resulted in bilateral retrograde labeling of the PVN neurons. Unilateral microinjections of biotinylated dextran amine into the PVN resulted in anterograde labeling of axons and terminals in the mNTS bilaterally and the labeled terminals exhibited vesicular glutamate transporter-2 immunoreactivity. These results indicated that 1) a tonically active glutamatergic bilateral projection from the PVN to the mNTS exists; 2) bilateral blockade of ionotropic glutamate receptors in the mNTS exaggerates the increases in MAP and GSNA, but not heart rate, to the chemical stimulation of the PVN; and 3) this projection may serve as a restraint mechanism for excitatory cardiovascular effects of PVN stimulation.
We use doubly phase modulated light to measure both the length and the linewidth of an optical resonator with high precision. The first modulation is at RF frequencies and is set near a multiple of ...the free spectral range, whereas the second modulation is at audio frequencies to eliminate offset errors at DC. The light in transmission or in reflection of the optical resonator is demodulated while sweeping the RF frequency over the optical resonance. We derive expressions for the demodulated power in transmission, and show that the zero crossings of the demodulated signal in transmission serve as a precise measure of the cavity linewidth at half maximum intensity. We demonstrate the technique on two resonant cavities, with lengths 16 m and a 4 km, and achieve an absolute length accuracy as low as 70 ppb. The cavity width for the 16 m cavity was determined with an accuracy of approximately 6000 ppm. Through an analysis of the systematic errors we show that this result could be substantially improved with the reduction of technical sources of uncertainty.
To improve physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD), providing a target PA value based on the individual patient's condition may be a useful interventional ...strategy. However, to determine the target value, a predictive PA value for each patient is required.
What is the reference equation consisting of PA-related factors to determine the predictive PA value for each patient with COPD?
In this prospective cross-sectional observational study, we measured the PA with a triaxial accelerometer and several other factors including demographic factors, pulmonary function, dyspnea, exercise capacity, muscle strength, nutrition, and indicators of several comorbidities in stable Japanese outpatients with COPD aged ≥40 years old and detected PA-related factors by a multiple regression analysis and stepwise method. We created reference equations for four indices of PA using multiple linear regression equations.
Two hundred and twenty-seven patients were registered. The equations of duration at ≥2.0 metabolic equivalents (METs) and step count consisted of 4 factors: 6-minute walk distance, modified Medical Research Council dyspnea scale, anxiety score of the Hospital Anxiety and Depression Scale, and the forced expiratory volume in 1 second % of predicted value. Those of duration at ≥3.0 METs and total activity at ≥3.0 METs consisted of 5 factors: the above 4 factors and age or brain natriuretic peptide. There was no fixed bias or proportional bias between the measured and predictive values in patients with non-high measured PA values.
We determined reference equations for four indicators of PA using PA-related factors in Japanese patients with COPD. The predictive values calculated using the equations could be useful for deciding target PA values for each patient.
UMIN-CTR; No.: UMIN000025459; URL: https://www.umin.ac.jp/ctr/index.htm.
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