31 research outputs found
Bounding the distance from a reachable/controllable equisingular switched linear system to the set of non-reachable/uncontrollable ones
No necessary and sufficient condition for reachability of switched linear singular systems has been found in general, but only in the case of the so-called “equisingular systems”. In this case, it is possible to obtain an upper bound for the distance between a controllable equisingular system and the set of uncontrollable onesPeer ReviewedPostprint (author's final draft
R&D inputs and productivity growth in China
The relationship between investment in R&D and productivity growth have been well documented in the literature. So far little research has been done on this topic for China, in part due to data limitations. Using the perpetual inventory method (PIM), this paper first estimates the R&D stock in China between 1978 and 2002. If R&D stock is measured, we can then estimate the elasticity of output with respect to R&D, thus estimate the contribution of R&D investment to output in China. The paper finds China’s economic growth mainly depends on capital input and that the impact of R&D capital on China’s growth is insignificant between 1978 and 2002. Then the essay examines the impact of R&D input on Total Factor Productivity (TFP), and finds that R&D input explains 30% of TFP change in China between 1980 and 2000 and that one percent increase in R&D input leads to 0.27 percent increase in TFP in China. The essay also finds that TFP in China has experienced an unusual fall since 1995.Growth; R&D; Total Factor Productivity
A Time-Varying Non-Parametric Methodology for Assessing Changes in QT Variability Unrelated to Heart Rate Variability
OBJECTIVE: To propose and test a novel methodology to measure changes in QT interval variability (QTV) unrelated to RR interval variability (RRV) in non-stationary conditions. METHODS: Time-frequency coherent and residual spectra representing QTV related (QTVrRRV) and unrelated (QTVuRRV) to RRV, respectively, are estimated using time-frequency Cohen's class distributions. The proposed approach decomposes the non-stationary output spectrum of any two-input one-output model with uncorrelated inputs into two spectra representing the information related and unrelated to one of the two inputs, respectively. An algorithm to correct for the bias of the time-frequency coherence function between QTV and RRV is proposed to provide accurate estimates of both QTVuRRV and QTVrRRV. Two simulation studies were conducted to assess the methodology in challenging non-stationary conditions and data recorded during head-up tilt in 16 healthy volunteers were analyzed. RESULTS: In the simulation studies, QTVuRRV changes were tracked with only a minor delay due to the filtering necessary to estimate the non-stationary spectra. The correlation coefficient between theoretical and estimated patterns was >0.92 even for extremely noisy recordings (SNR in QTV =-10dB). During head-up tilt, QTVrRRV explained the largest proportion of QTV, whereas QTVuRRV showed higher relative increase than QTV or QTVrRRV in all spectral bands (P<0.05 for most pairwise comparisons). CONCLUSION: The proposed approach accurately tracks changes in QTVuRRV. Head-up tilt induced a slightly greater increase in QTVuRRV than in QTVrRRV. SIGNIFICANCE: The proposed index QTVuRRV may represent an indirect measure of intrinsic ventricular repolarization variability, a marker of cardiac instability associated with sympathetic ventricular modulation and sudden cardiac death
The demographics of galactic bulges in the SDSS database
We present a new database of our two-dimensional bulge–disk decompositions for 14,233 galaxies drawn from Sloan Digital Sky Survey DR12 in order to examine the properties of bulges residing in the local universe (0.005 < z < 0.05). We performed decompositions in the g and r bands by utilizing the galfit software. The bulge colors and bulge-to-total ratios are found to be sensitive to the details in the decomposition technique, and hence we hereby provide full details of our method. The g − r colors of bulges derived are almost constantly red regardless of bulge size, except for the bulges in the low bulge-to-total ratio galaxies (B/T r lesssim 0.3). Bulges exhibit similar scaling relations to those followed by elliptical galaxies, but the bulges in galaxies with lower bulge-to-total ratios clearly show a gradually larger departure in slope from the elliptical galaxy sequence. The scatters around the scaling relations are also larger for the bulges in galaxies with lower bulge-to-total ratios. Both the departure in slopes and larger scatters likely originate from the presence of young stars. The bulges in galaxies with low bulge-to-total ratios show signs of a frosting of young stars so substantial that their luminosity-weighted Balmer-line ages are as small as 1 Gyr in some cases. While bulges seem largely similar in optical properties to elliptical galaxies, they do show clear and systematic departures as a function of bulge-to-total ratio. The stellar properties and perhaps associated formation processes of bulges seem much more diverse than those of elliptical galaxies
R&D inputs and productivity growth in China
The relationship between investment in R&D and productivity growth have been well documented in the literature. So far little research has been done on this topic for China, in part due to data limitations. Using the perpetual inventory method (PIM), this paper first estimates the R&D stock in China between 1978 and 2002. If R&D stock is measured, we can then estimate the elasticity of output with respect to R&D, thus estimate the contribution of R&D investment to output in China. The paper finds China’s economic growth mainly depends on capital input and that the impact of R&D capital on China’s growth is insignificant between 1978 and 2002. Then the essay examines the impact of R&D input on Total Factor Productivity (TFP), and finds that R&D input explains 30% of TFP change in China between 1980 and 2000 and that one percent increase in R&D input leads to 0.27 percent increase in TFP in China. The essay also finds that TFP in China has experienced an unusual fall since 1995
R&D inputs and productivity growth in China
The relationship between investment in R&D and productivity growth have been well documented in the literature. So far little research has been done on this topic for China, in part due to data limitations. Using the perpetual inventory method (PIM), this paper first estimates the R&D stock in China between 1978 and 2002. If R&D stock is measured, we can then estimate the elasticity of output with respect to R&D, thus estimate the contribution of R&D investment to output in China. The paper finds China’s economic growth mainly depends on capital input and that the impact of R&D capital on China’s growth is insignificant between 1978 and 2002. Then the essay examines the impact of R&D input on Total Factor Productivity (TFP), and finds that R&D input explains 30% of TFP change in China between 1980 and 2000 and that one percent increase in R&D input leads to 0.27 percent increase in TFP in China. The essay also finds that TFP in China has experienced an unusual fall since 1995
Hubungan kemampuan membaca dengan penyelesaian soal pada Mata Pelajaran Bahasa Indonesia Kelas II MINU Ngingas Waru Sidoarjo
Latar belakang penelitian ini yaitu banyaknya siswa yang mengalami kesulitan saat harus mengerjakan soal ulangan tengah semester secara mandiri. Dalam hal ini peneliti melihat bahwa kemampuan membaca pemahaman yang baik akan memudahkan siswa dalam menyelesaikan soal. Tujuan dari penelitian ini yaitu, 1) Untuk mengetahui kondisi kemampuan membaca siswa kelas II di MINU Ngingas Waru. 2) Untuk memahami faktor yang menjadi penghambat pada kemampuan membaca siswa kelas II di MINU Ngingas Waru. 3) Untuk mengetahui hubungan antara kemampuan membaca dengan kemampuan penyelesaian soal pada mata pelajaran Bahasa Indonesia kelas II di MINU Ngingas Waru. Jenis penelitian ini yaitu penelitian mixed methods. Dengan jumlah sampel sebanyak 28 siswa kelas II MINU Ngingas Waru pada semester genap tahun ajaran 2021/2022 yang ditentukan dengan teknik simple randon sampling. Instrumen pengumpulan data yang digunakan yaitu dokumentasi, wawancara, dan tes. Teknik analisis data yang digunakan yaitu analisis statistik deskriptif dan perhitungan statistik inferensial dengan rumus product momen. Hasil penelitian ini yaitu : 1) Kemampuan membaca siswa kelas II MINU Ngingas Waru berada pada kategori baik, karena sebagian besar siswa sudah mampu memahami isi bacaan dengan sangat baik. 2) Faktor yang menjadi penghambat pada kemampuan membaca yaitu motivasi serta dukungan dari orang tua yang kurang, waktu pembelajaran di sekolah yang terbatas, dan kurangnya kesiapan siswa untuk menerima pembelajaran. 3) Hasil perhitungan korelasi product moment dengan nilai r hitung (0,635) > r tabel (0,374). Hasil ini menunjukkan bahwa Ha diterima sebab terdapat hubungan yang positif dan signifikan antara kemampuan membaca dengan penyelesian soal pada mata pelajaran bahasa Indonesia kelas II di MINU Ngingas Waru
Age-Related Differences in the Effect of Psychological Distress on Mortality: Type D Personality in Younger versus Older Patients with Cardiac Arrhythmias
Background. Mixed findings in biobehavioral research on heart disease may partly be attributed to age-related differences in the prognostic value of psychological distress. This study sought to test the hypothesis that Type D (distressed) personality contributes to an increased mortality risk following implantable cardioverter defibrillator (ICD) treatment in younger patients but not in older patients. Methods. The Type D Scale (DS14) was used to assess general psychological distress in 455 younger (≤70 y, m = 59.1) and 134 older (>70 y, m = 74.3) ICD patients. End points were all-cause mortality and cardiac death after a median follow-up of 3.2 years. Results. Older patients had more advanced heart failure and a higher mortality rate (n = 34/25%) than younger patients (n = 60/13%), P = 0.001. Cardiac resynchronization therapy (CRT), but not Type D personality, was associated with increased mortality in older patients. Among younger patients, however, Type D personality was associated with an adjusted hazard ratio = 1.91 (95% CI 1.09–3.34) and 2.26 (95% CI 1.16–4.41) for all-cause and cardiac mortality; other predictors were increasing age, CRT, appropriate shocks, ACE-inhibitors, and smoking. Conclusion. Type D personality was independently associated with all-cause and cardiac mortality in younger ICD patients but not in older patients. Cardiovascular research needs to further explore age-related differences in psychosocial risk