This paper summarizes a set of six benchmark systems for the analysis and control of electromechanical oscillations in power systems, recommended by the IEEE Task Force on Benchmark Systems for ...Stability Controls of the Power System Dynamic Performance Committee. The benchmark systems were chosen for their tutorial value and particular characteristics leading to control the system design problems relevant to the research community. For each benchmark, the modeling guidelines are provided, along with eigenvalues and time-domain results produced with at least two simulation softwares, and one possible control approach is provided for each system as well. Researchers and practicing engineers are encouraged to use these benchmark systems when assessing new oscillation damping control strategies.
This paper presents a new approach in estimating important parameters of power system transient stability model such as inertia constant H and direct axis transient reactance xd ' in real time. It ...uses a variation of unscented Kalman filter (UKF) on the phasor measurement unit (PMU) data. The accurate estimation of these parameters is very important for assessing the stability and tuning the adaptive protection system on power swing relays. The effectiveness of the method is demonstrated in a simulated data from 16-machine 68-bus system model. The paper also presents the performance comparison between the UKF and EKF method in estimating the parameters. The robustness of method is further validated in the presence of noise that is likely to be in the PMU data in reality.
NAC no apical meristem (NAM), Arabidopsis thaliana transcription activation factor ATAF1/2 and cup-shaped cotyledon (CUC2) proteins belong to one of the largest plant-specific transcription factor ...(TF) families and play important roles in plant development processes, response to biotic and abiotic cues and hormone signalling. Our genome-wide analysis identified 110 StNAC genes in potato encoding for 136 proteins, including 14 membrane-bound TFs. The physical map positions of StNAC genes on 12 potato chromosomes were non-random, and 40 genes were found to be distributed in 16 clusters. The StNAC proteins were phylogenetically clustered into 12 subgroups. Phylogenetic analysis of StNACs along with their Arabidopsis and rice counterparts divided these proteins into 18 subgroups. Our comparative analysis has also identified 36 putative TNAC proteins, which appear to be restricted to Solanaceae family. In silico expression analysis, using Illumina RNA-seq transcriptome data, revealed tissue-specific, biotic, abiotic stress and hormone-responsive expression profile of StNAC genes. Several StNAC genes, including StNAC072 and StNAC101that are orthologs of known stress-responsive Arabidopsis RESPONSIVE TO DEHYDRATION 26 (RD26) were identified as highly abiotic stress responsive. Quantitative real-time polymerase chain reaction analysis largely corroborated the expression profile of StNAC genes as revealed by the RNA-seq data. Taken together, this analysis indicates towards putative functions of several StNAC TFs, which will provide blue-print for their functional characterization and utilization in potato improvement.
Background & objectives: India has been reporting the cases of coronavirus disease 2019 (COVID-19) since January 30, 2020. The Indian Council of Medical Research (ICMR) formulated and established ...laboratory surveillance for COVID-19. In this study, an analysis of the surveillance data was done to describe the testing performance and descriptive epidemiology of COVID-19 cases by time, place and person.
Methods: The data were extracted from January 22 to April 30, 2020. The frequencies of testing performance were described over time and by place. We described cases by time (epidemic curve by date of specimen collection; seven-day moving average), place (area map) and person (attack rate by age, sex and contact status), and trends were represented along with public health measures and events.
Results: Between January 22 and April 30, 2020, a total of 1,021,518 individuals were tested for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Testing increased from about 250 individuals per day in the beginning of March to 50,000 specimens per day by the end of April 2020. Overall, 40,184 (3.9%) tests were reported positive. The proportion of positive cases was highest among symptomatic and asymptomatic contacts, 2-3-fold higher than among those with severe acute respiratory infection, or those with an international travel history or healthcare workers. The attack rate (per million) by age was highest among those aged 50-69 yr (63.3) and was lowest among those under 10 yr (6.1). The attack rate was higher among males (41.6) than females (24.3). The secondary attack rate was 6.0 per cent. Overall, 99.0 per cent of 736 districts reported testing and 71.1 per cent reported COVID-19 cases.
Interpretation & conclusions: The coverage and frequency of ICMR's laboratory surveillance for SARS-CoV-2 improved over time. COVID-19 was reported from most parts of India, and the attack rate was more among men and the elderly and common among close contacts. Analysis of the data indicates that for further insight, additional surveillance tools and strategies at the national and sub-national levels are needed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Partial nephrectomy is performed with the aim to preserve renal function. But the occurrence of postoperative acute kidney injury (AKI) can interfere with this goal. Our primary aim was to evaluate ...associations between pre-specified modifiable factors and estimated glomerular filtration rate after partial nephrectomy. Our secondary aims were to evaluate associations between pre-specified modifiable factors and both serum creatinine concentration and type of nephrectomy.
The records of 1955 patients who underwent partial nephrectomy were collected. Postoperative estimated glomerular filtration rate (eGFR) was used as the primary outcome measure. Twenty modifiable risk factors were studied. A repeated-measures linear model with autoregressive within-subject correlation structure was used. The interaction between all the factors and type of nephrectomy was also studied.
A total of 1187 (61%) patients had no kidney injury, 647 (33%) had stage I, 80 (4%) had stage II, and 41 (2%) had stage III injury. The mean eGFR increased an estimated 0.83 (99.76% CI 0.79–0.88) ml min−1 1.73 m−2 for a unit increase in baseline eGFR. Mean eGFR was 2.65 (99.76% CI: 0.13, 5.18) ml min−1 1.73 m−2 lower in patients with hypertension. Mean eGFR decreased 0.42 (99.76% CI: 0.22, 0.62) ml min−1 1.73 m−2 for a 10-minute longer in duration of procedure and decreased 2.09 (99.76% CI: 1.39, 2.80) ml min−1 1.73 m−2 for a 10-minute longer in ischemia time. It was 3.53 (99.76% CI: 0.83, 6.23) ml min−1 1.73 m−2 lower for patients who received warm ischemia as compared to cold ischemia.
Potentially modifiable factors associated with AKI in the postoperative period were identified as baseline renal function, preoperative hypertension, longer duration of surgical time and ischaemia time, and warm ischaemia.
Objective: The objective of this study is to analyze the role of diagnostic hysterolaparoscopy (DHL) for evaluation of infertility in a tertiary care hospital. Materials and Methods: This ...retrospective study was conducted from July 2014 to June 2016. Results: Out of 151 patients, 58.28% and 41.72% had primary and secondary infertility, respectively. In primary infertility group 37.5% and in secondary infertility group 49.2% had abnormal findings. Most common finding was adnexal adhesions (pelvic inflammatory disease) and laparoscopic findings were more common than the hysteroscopic ones. Conclusion: DHL was helpful in finding some reversible causes of infertility such as adnexal adhesions, tubal blockade, and uterine synechiae, etc.
Composites with promising electrical and magnetic properties have dragged the attention of the current research interest as compared to the single-phase material due to their potential applications ...in sensor and charge storage devices. Hence, composites (1−
x
)Bi
5
Ti
3
FeO
15
−(
x
)La
0.67
Sr
0.33
MnO
3
with different compositions (
x
= 0, 0.1, 0.2, 0.3, and 0.4) are investigated via the sol–gel precursor hybrid method. The structural analysis and phase purity of the composites are examined by the Rietveld refinement of X-ray diffraction spectra. This reveals the existence of the Bragg peaks corresponding to the perovskite (BTFO) as well as the manganite (LSMO) phase. The strain at the interface of the BTFO and LSMO phases causes the change in lattice parameters and shifting of phonon modes in the Raman spectra. X-ray photoelectron spectroscopy (XPS) confirms the mixed-valence state of Mn
3+
/Mn
4+
and Fe
3+
/Fe
2+
ions, endorsing the oxygen vacancies in the prepared composites. The dielectric permittivity increases with the increase of the LSMO phase, which is ascribed to interfacial lattice strain. Using the modified Debye model, the dispersive behavior of frequency-dependent dielectric permittivity is explained. Room temperature M–H data reveal the enhancement of
M
r
(~4.74 × 10
–3
emu/g) by 13 times and
M
max
(~ 0.415 emu/g) by 6 times for 40% LSMO composite which is ascribed to the inclusion of the manganite (LSMO) phase. Theoretically, the magnetization value is also estimated from Vegard’s law and compared with the experimental result.
We have investigated the structural, magnetic, dielectric, and magnetodielectric properties of brownmillerite-structured polycrystalline KBiFe
2
O
5
(KBFO) sample synthesized using conventional ...solid-state reaction route. Monoclinic structure with
P
2/
c
space group is determined from Rietveld refined X-ray diffraction (XRD) analysis. Temperatures-dependent magnetic and dielectric data show a broad hump around 510 °C, indicating the existence of magnetodielectric effect in KBFO. Room-temperature M–H hysteresis measurement possesses a weak ferromagnetic order (
M
R
=
0.006
emu/g and
H
c
= 1100 Oe) originating from the canted Fe
3+
moments due to antiferromagnetic ordering. This canted Fe
3+
moment is also reflected in magnetic field variation of magnetodielectric (MD) measurement at room temperature, in which MD does not trace the original path by reversing the field. The highest magnetodielectric response is obtained to be ~ − 1.8% at room temperature. Modulus and complex impedance spectrum analysis attributes the bulk contribution to the observed room-temperature magnetodielectric at high frequency (> 10 kHz) and extrinsic contribution
(
< 10 kHz) at low frequency. The presence of temperature-dependent and non-Debye (
β
<
1
) type of relaxation in prepared sample is confirmed from the extracted grain (
R
g
) and grain boundary (
R
gb
) contribution at different temperature. The frequency-dependent ac conductivity at different temperature follows Jonscher’s power law. The extracted power exponent “
n
” is decreased with increase in temperature. This behavior (
n
∝
1/T
) suggests that the ac conduction mechanism of KBFO follows correlated barrier hoping (CBH) model.
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