Journal articles: 'Ka fei'

1

Davies, K. J. A., A. Sevanian, S. F. Muakkassah-Kelly, and P. Hochstein. "Uric acid-iron ion complexes. A new aspect of the antioxidant functions of uric acid." Biochemical Journal 235, no. 3 (May 1, 1986): 747–54. http://dx.doi.org/10.1042/bj2350747.

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In order to survive in an oxygen environment, aerobic organisms have developed numerous mechanisms to protect against oxygen radicals and singlet oxygen. One such mechanism, which appears to have attained particular significance during primate evolution, is the direct scavenging of oxygen radicals, singlet oxygen, oxo-haem oxidants and hydroperoxyl radicals by uric acid. In the present paper we demonstrate that another important ‘antioxidant’ property of uric acid is the ability to form stable co-ordination complexes with iron ions. Formation of urate-Fe3+ complexes dramatically inhibits Fe3+-catalysed ascorbate oxidation, as well as lipid peroxidation in liposomes and rat liver microsomal fraction. In contrast with antioxidant scavenger reactions, the inhibition of ascorbate oxidation and lipid peroxidation provided by urate's ability to bind iron ions does not involve urate oxidation. Association constants (Ka) for urate-iron ion complexes were determined by fluorescence-quenching techniques. The Ka for a 1:1 urate-Fe3+ complex was found to be 2.4 × 10(5), whereas the Ka for a 1:1 urate-Fe2+ complex was determined to be 1.9 × 10(4). Our experiments also revealed that urate can form a 2:1 complex with Fe3+ with an association constant for the second urate molecule (K'a) of approx. 4.5 × 10(5). From these data we estimate an overall stability constant (Ks approximately equal to Ka × K'a) for urate-Fe3+ complexes of approx. 1.1 × 10(11). Polarographic measurements revealed that (upon binding) urate decreases the reduction potential for the Fe2+/Fe3+ half-reaction from −0.77 V to −0.67 V. Thus urate slightly diminishes the oxidizing potential of Fe3+. The present results provide a mechanistic explanation for our previous report that urate protects ascorbate from oxidation in human blood. The almost saturating concentration of urate normally found in human plasma (up to 0.6 mM) represents 5-10 times the plasma ascorbate concentration, and is orders of magnitude higher than the ‘free’ iron ion concentration. These considerations point to the physiological significance of our findings.

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2

Williams, Tony. "Tony Leung Ka-Fai: The Other Tony Leung." Asian Cinema 16, no. 1 (May 26, 2012): 239–62. http://dx.doi.org/10.1386/ac.16.1.239_1.

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3

Wu, Chung Hsin, Chih Hao Lai, and Wei Yang Chung. "Electrical Energy per Order and Photodegradation Efficiency of Advanced Oxidation Processes." Applied Mechanics and Materials 291-294 (February 2013): 764–67. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.764.

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This study investigates the decolorization of C.I. Reactive Red 2 (RR2) by the UV/TiO2, UV/ZnO, UV/TiO2/ZnO, O3, UV/O3, O3/MnO2, UV/H2O2, UV/H2O2/Fe3+, UV/O3/H2O2, and UV/O3/H2O2/Fe3+ systems. The values of the electrical energy per order of pollutant removal (EEO) and decolorization rate were determined and compared for all tested systems. The decolorization rate constant (ka) fit pseudo-first-order kinetics. Under 365 nm irradiation, the highest ka value and lowest EEO value were with the UV/O3 (0.0924 min-1) and O3/MnO2 (1.68) systems, respectively. Moreover, under 254 nm irradiation, the highest ka value and lowest EEO value were with the UV/O3/H2O2/Fe3+ (0.096 min-1) and UV/H2O2/Fe3+ (2.01) systems, respectively.

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4

Goyal, Ashima, and Vaishnavi Sharma. "Estimating the Relationship Between the Current Account, the Capital Account and Investment for India." Foreign Trade Review 54, no. 1 (January 3, 2019): 29–45. http://dx.doi.org/10.1177/0015732518810832.

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Causality from the capital account (KA) to the current account (CA) of the balance of payments indicates disruption from capital flows while the reverse can indicate smooth financing of the CA that allows investment to exceed domestic savings. A three-variable vector autoregression tests for Granger causality between the Indian CA, KA, KA components, and gross fixed capital formation (GFCF) over 2000–01Q1 to 2015–16Q3. Since a CA deficit indicates an excess of investment over savings it is useful to estimate which type of capital flows affect investment. No causality is found to exist in any direction between the KA and the CA. There is only indirect causality through some components. Of the capital flow components, only FDI affects GFCF. The latter consistently affects the CA. The CA affects debt portfolio flows and non-resident deposits, suggesting these were used to finance the CA, but they were not causal for GFCF. Volatile flows, therefore, did not deteriorate the CA, but they also did not contribute to GFCF. India’s gradual KA convertibility may have mitigated shocks from the KA. Long-term sustainability, however, requires FDI to increase as compared to other types of flows. JEL Codes: F21, F32

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Kehres, David G., Anuradha Janakiraman, James M. Slauch, and Michael E. Maguire. "SitABCD Is the Alkaline Mn2+ Transporter of Salmonella enterica Serovar Typhimurium." Journal of Bacteriology 184, no. 12 (June 15, 2002): 3159–66. http://dx.doi.org/10.1128/jb.184.12.3159-3166.2002.

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ABSTRACT MntH, a bacterial homolog of the mammalian natural resistance-associated macrophage protein 1 (Nramp1), is a primary Mn2+ transporter of Salmonella enterica serovar Typhimurium and Escherichia coli. S. enterica serovar Typhimurium MntH expression is important for full virulence; however, strains carrying an mntH deletion are only partially attenuated and display no obvious signs of Mn2+ deficiency. We noted that promoter sequences for mntH and for the putative Fe2+ transporter sitABCD appeared to have the same regulatory element responsive to Mn2+ and so hypothesized that sitABCD could transport Mn2+ with high affinity. We have now characterized transport by SitABCD in S. enterica serovar Typhimurium using 54Mn2+ and 55Fe2+ and compared its properties to those of MntH. SitABCD mediates the influx of Mn2+ with an apparent affinity (Ka ) identical to that of MntH, 0.1 μM. It also transports Fe2+ but with a Ka 30 to 100 times lower, 3 to 10 μM. Inhibition of 54Mn2+ transport by Fe2+ and of 55Fe2+ transport by Mn2+ gave inhibition constants comparable to each cation's Ka for influx. Since micromolar concentrations of free Fe2+ are improbable in a biological system, we conclude that SitABCD functions physiologically as a Mn2+ transporter. The cation inhibition profiles of SitABCD and MntH are surprisingly similar for two structurally and energetically unrelated transporters, with a Cd2+ Ki of ≈1 μM and a Co2+ Ki of ≈20 μM and with Ni2+, Cu2+, and Fe3+ inhibiting both transporters only at concentrations of >0.1 mM. The one difference is that Zn2+ exhibits potent inhibition of SitABCD (Ki = 1 to 3 μM) but inhibits MntH weakly (Ki > 50 μM). We have previously shown that MntH transports Mn2+ most effectively under acidic conditions. In sharp contrast, SitABCD has almost no transport capacity at acid pHs and optimally transports Mn2+ at slightly alkaline pHs. Overall, coupled with evidence that each transporter is multiply but distinctly regulated at the transcriptional level, the distinct transport properties of MntH versus SitABCD suggest that each transporter may be specialized for Mn2+ uptake in different physiological environments.

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6

Li, Jian, Yaqi Zhang, Shen Yang, Zhenhua Lu, Guiling Li, Shangyi Wu, Da-Ren Wu, et al. "The Beneficial Effects of Edible Kynurenic Acid from Marine Horseshoe Crab (Tachypleus tridentatus) on Obesity, Hyperlipidemia, and Gut Microbiota in High-Fat Diet-Fed Mice." Oxidative Medicine and Cellular Longevity 2021 (May 3, 2021): 1–13. http://dx.doi.org/10.1155/2021/8874503.

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The marine horseshoe crab (Tachypleus tridentatus) has been considered as food and traditional medicine for many years. Kynurenic acid (KA) was isolated from horseshoe crab in this study for the first time in the world. A previous study in 2018 reported that intraperitoneal administration of KA prevented high-fat diet- (HFD-) induced body weight gain. Now, we investigated the effects of intragastric gavage of KA on HFD mice and found that KA (5 mg/kg/day) inhibited both the body weight gain and the increase of average daily energy intake. KA reduced serum triglyceride and increased serum high-density lipoprotein cholesterol. KA inhibited HFD-induced the increases of serum low-density lipoprotein cholesterol, coronary artery risk index, and atherosclerosis index. KA also suppressed HFD-induced the increase of the ratio of Firmicutes to Bacteroidetes (two dominant gut microbial phyla). KA partially reversed HFD-induced the changes in the composition of gut microbial genera. These overall effects of KA on HFD mice were similar to that of simvastatin (positive control). But the effects of 1.25 mg/kg/day KA on HFD-caused hyperlipidemia were similar to the effects of 5 mg/kg/day simvastatin. The pattern of relative abundance in 40 key genera of gut microbiota from KA group was closer to that from the normal group than that from the simvastatin group. In addition, our in vitro results showed the potential antioxidant activity of KA, which suggests that the improvement effects of KA on HFD mice may be partially associated with antioxidant activity of KA. Our findings demonstrate the potential role of KA as a functional food ingredient for the treatment of obesity and hyperlipidemia as well as the modulation of gut microbiota.

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7

Yang, Hongming, and Zhigang Cao. "An adaptive FEC scheme for Ka-band satellite communications." Journal of Electronics (China) 22, no. 1 (January 2005): 18–24. http://dx.doi.org/10.1007/bf02687946.

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8

Beukema, Steven P., R. V. Krishnamurthy, N. Juyal, N. Basavaiah, and A. K. Singhvi. "Monsoon variability and chemical weathering during the late Pleistocene in the Goriganga basin, higher central Himalaya, India." Quaternary Research 75, no. 3 (May 2011): 597–604. http://dx.doi.org/10.1016/j.yqres.2010.12.016.

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AbstractStable isotope analysis along with radiocarbon and luminescence dating of late Pleistocene lacustrine deposits at Burfu in the higher central Himalaya are used to interpret hydrologic changes in the lake basin. From 15.5 ka to ~ 14.5 ka the Burfu lake was largely fed by melting glaciers. A warming event at 14.5 ka suggests an enhanced monsoon and increased carbonate weathering. From ~ 13.5 ka to ~ 12.5 ka the isotopic data suggest large-amplitude climate variability. Following this, the isotope data suggest a short-lived, abrupt cooling event, comprising a ~ 300-yr intense cool period followed by a ~ 500-yr interval of moderate climate. A shift in isotope values at ~ 11.3 ka may signify a strengthening monsoon in this region. The inferred climatic excursions appear to be correlative, at least qualitatively, with global climatic events, and perhaps the Burfu lake sequence provides regional evidence of globally recorded excursions. This study also suggests a potential use of radiocarbon ages in specific environments as a paleoenvironmental proxy.

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9

Madhav, B. T. P., G. Jyothsna Devi, and T. Anilkumar. "A CPW-fed Sigma-shaped MIMO Antenna for Ka Band and 5G Communication Applications." Journal of Telecommunications and Information Technology 8 (December 28, 2018): 97–106. http://dx.doi.org/10.26636/jtit.2018.123717.

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This article presents a MIMO compact antenna measuring 45×45×1.6 mm, on the FR4 substrate, proposed for Ka band and 5G communication applications. The proposed design is suitable to overcome the issues connected with massive MIMO. It has four-sigma-shaped radiating elements and a c-shaped ground plane with coplanar waveguide feeding. Its compact dimensions suit it for most existing communications systems. The aerial operates in the 21–30 GHz range, which covers Ka and 5G communication bands. The proposed antenna exhibits the average eﬃciency of more than 76% within its operating band and gives a minimum signal to noise plus interference ratio. The presented antenna covers several services, such as Ka band satellite downlink applications and future 5G communication applications.

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10

Zhang, Jia-ying, Ying Yin, Li Ni, Quan Long, Li You, Qian Zhang, Shan-yan Lin, and Jing Chen. "Low-protein diet supplemented with ketoacids ameliorates proteinuria in 3/4 nephrectomised rats by directly inhibiting the intrarenal renin–angiotensin system." British Journal of Nutrition 116, no. 9 (October 18, 2016): 1491–501. http://dx.doi.org/10.1017/s0007114516003536.

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AbstractLow-protein diet plus ketoacids (LPD+KA) has been reported to decrease proteinuria in patients with chronic kidney diseases (CKD). However, the mechanisms have not been clarified. As over-activation of intrarenal renin–angiotensin system (RAS) has been shown to play a key role in the progression of CKD, the current study was performed to investigate the direct effects of LPD+KA on intrarenal RAS, independently of renal haemodynamics. In this study, 3/4 subtotal renal ablated rats were fed 18 % normal-protein diet (Nx-NPD), 6 % low-protein diet (Nx-LPD) or 5 % low-protein diet plus 1 % ketoacids (Nx-LPD+KA) for 12 weeks. Sham-operated rats fed NPD served as controls. The level of proteinuria and expression of renin, angiotensin II (AngII) and its type 1 receptors (AT1R) in the renal cortex were markedly higher in Nx-NPD group than in the sham group. LPD+KA significantly decreased the proteinuria and inhibited intrarenal RAS activation. To exclude renal haemodynamic impact on intrarenal RAS, the serum samples derived from the different groups were added to the culture medium of mesangial cells. It showed that the serum from Nx-NPD directly induced higher expression of AngII, AT1R, fibronectin and transforming growth factor-β1 in the mesangial cells than in the control group. Nx-LPD+KA serum significantly inhibited these abnormalities. Then, proteomics and biochemical detection suggested that the mechanisms underlying these beneficial effects of LPD+KA might be amelioration of the nutritional metabolic disorders and oxidative stress. In conclusion, LPD+KA could directly inhibit the intrarenal RAS activation, independently of renal haemodynamics, thus attenuating the proteinuria in CKD rats.

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11

Hu, Zhi Hui, Yong Hua Jiang, and Xiang Ling. "Design of Ka-Band Inset-Fed Conical Conformal Patch Antenna." Applied Mechanics and Materials 336-338 (July 2013): 1699–702. http://dx.doi.org/10.4028/www.scientific.net/amm.336-338.1699.

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Conical conformal microstrip patch antenna is very important in wireless communication and microwave instrument. In this paper, a Ka-band rectangular inset-fed microstrip patch antenna which conforms to a conical surface has been designed, the specific designed method and parameters were given. Then a conical conformal microstrip antenna is simulated by CST, the difference between planar antenna and conical conformal antenna has been discussed, and the effect of surface curvature on conical conformal antenna resonant frequency of has been analyzed.

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12

Sánchez-Cabello, Carlos, Luis Fernando Herrán, Ashraf Uz Zaman, and Eva Rajo-Iglesias. "Ka band microstrip fed slot array antenna with PMC packaging." IET Microwaves, Antennas & Propagation 14, no. 14 (November 25, 2020): 1837–45. http://dx.doi.org/10.1049/iet-map.2020.0565.

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13

Zhao, Shuang, and Dian Ren Chen. "Design of Ka-Band Conformal Microstrip Patch Antenna." Advanced Materials Research 1046 (October 2014): 289–92. http://dx.doi.org/10.4028/www.scientific.net/amr.1046.289.

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It is very difficult to accurately analyze the performance of the antenna conformed to the elastomer because of the complex structure. Conformal coordinate method is an effective method for analyzing the complex structure of the antenna. Based on the conformal coordinate method, the millimeter-wave monolithic conformal microstrip antenna is analyzed in this paper. Using the traditional way of microstrip-fed - the middle microstrip feeding, we design the microstrip patch unit. Then we use the HFSS to simulate the antenna.

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Chen, Chen-Sheng, Bo-Yi Pan, Ping-Hsuan Tsai, Fang-Yu Chen, Wen-Chin Yang, and Ming-Yi Shen. "Kansuinine A Ameliorates Atherosclerosis and Human Aortic Endothelial Cell Apoptosis by Inhibiting Reactive Oxygen Species Production and Suppressing IKKβ/IκBα/NF-κB Signaling." International Journal of Molecular Sciences 22, no. 19 (September 24, 2021): 10309. http://dx.doi.org/10.3390/ijms221910309.

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Reactive oxygen species (ROS)-induced vascular endothelial cell apoptosis is strongly associated with atherosclerosis progression. Herein, we aimed to examine whether Kansuinine A (KA), extracted from Euphorbia kansui L., prevents atherosclerosis development in a mouse model and inhibits cell apoptosis through oxidative stress reduction. Atherosclerosis development was analyzed in apolipoprotein E-deficient (ApoE−/−) mice fed a high-fat diet (HFD) using Oil Red O staining and H&E staining. Human aortic endothelial cells (HAECs) were treated with KA, followed by hydrogen peroxide (H2O2), to investigate the KA-mediated inhibition of ROS-induced oxidative stress and cell apoptosis. Oil Red O staining and H&E staining showed that atherosclerotic lesion size was significantly smaller in the aortic arch of ApoE−/− mice in the HFD+KA group than that in the aortic arch of those in the HFD group. Further, KA (0.1–1.0 μM) blocked the H2O2-induced death of HAECs and ROS generation. The H2O2-mediated upregulation of phosphorylated IKKβ, phosphorylated IκBα, and phosphorylated NF-κB was suppressed by KA. KA also reduced the Bax/Bcl-2 ratio and cleaved caspase-3 expression, preventing H2O2-induced vascular endothelial cell apoptosis. Our results indicate that KA may protect against ROS-induced endothelial cell apoptosis and has considerable clinical potential in the prevention of atherosclerosis and cardiovascular diseases.

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Garcia, Anna L., Jeffrey R. Knott, Shannon A. Mahan, and Jordon Bright. "Geochronology and paleoenvironment of pluvial Harper Lake, Mojave Desert, California, USA." Quaternary Research 81, no. 2 (March 2014): 305–17. http://dx.doi.org/10.1016/j.yqres.2013.10.008.

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AbstractAccurate reconstruction of the paleo-Mojave River and pluvial lake (Harper, Manix, Cronese, and Mojave) system of southern California is critical to understanding paleoclimate and the North American polar jet stream position over the last 500 ka. Previous studies inferred a polar jet stream south of 35°N at 18 ka and at ~ 40°N at 17–14 ka. Highstand sediments of Harper Lake, the upstream-most pluvial lake along the Mojave River, have yielded uncalibrated radiocarbon ages ranging from 24,000 to > 30,000 14C yr BP. Based on geologic mapping, radiocarbon and optically stimulated luminescence dating, we infer a ~ 45–40 ka age for the Harper Lake highstand sediments. Combining the Harper Lake highstand with other Great Basin pluvial lake/spring and marine climate records, we infer that the North American polar jet stream was south of 35°N about 45–40 ka, but shifted to 40°N by ~ 35 ka. Ostracodes (Limnocythere ceriotuberosa) from Harper Lake highstand sediments are consistent with an alkaline lake environment that received seasonal inflow from the Mojave River, thus confirming the lake was fed by the Mojave River. The ~ 45–40 ka highstand at Harper Lake coincides with a shallowing interval at downstream Lake Manix.

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Jung, Young-Bae. "Ka-band Microstrip Antenna Fed Circular Polarized Horn Array Antenna Design." Journal of IKEEE 17, no. 2 (June 30, 2013): 140–44. http://dx.doi.org/10.7471/ikeee.2013.17.2.140.

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17

Michelle Lim. "Traces of a Corporeal Archive: Choy Ka Fai + The SoftMachine Project." Journal of History of Modern Art ll, no. 39 (June 2016): 215–29. http://dx.doi.org/10.17057/kahoma.2016..39.009.

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18

Jung, Y. B., I. Yeom, and C. W. Jung. "Centre-fed series array antenna for K-/Ka-band electromagnetic sensors." IET Microwaves, Antennas & Propagation 6, no. 5 (2012): 588. http://dx.doi.org/10.1049/iet-map.2011.0355.

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19

Chilukuri, S., K. Dahal, and A. Lokam. "Multi-port Pattern diversity antenna for K and Ka-band application." Advanced Electromagnetics 7, no. 2 (March 1, 2018): 5–9. http://dx.doi.org/10.7716/aem.v7i2.687.

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A compact coplanar waveguide (CPW) fed reconfigurable antenna with pattern diversity using multi-port excitation is designed. The basic antenna consists of a circular patch of radius 2.5mm which is fed by four ports independently. By exciting the patch with each individual port, the direction of the radiation pattern changes by 900. With the use of CPW feed technique, a very wide impedance bandwidth of around 12GHz (21.65 – 33.87 GHz) covering the K-band and Ka-band is achieved. The proposed antenna can be used for different satellite communication applications like earth exploration, radio navigation and location, mobile satellite communications which comes under K-band and Ka-band. The measured return loss and pattern characteristic results are in good agreement with simulated ones.

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20

Loulijat, Azeddine, Hamid Chojaa, Mouncef El Marghichi, Naoufl Ettalabi, Abdelilah Hilali, Abdulwasa B. Barnawi, Z. M. S. Elbarbary, and Mahmoud A. Mossa. "Application and Comparison of a Modified Protection Scheme Utilizing a Proportional–Integral Controller with a Conventional Design to Enhance Doubly Fed Induction Generator Wind Farm Operations during a Balanced Voltage Dip." Processes 11, no. 10 (September 26, 2023): 2834. http://dx.doi.org/10.3390/pr11102834.

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The doubly fed induction generator (DFIG) is vulnerable to grid faults due to its direct stator connection, causing issues like excess stator current during voltage dips. Consequently, sensitive inverters suffer from increased currents, and the DC-link capacitor undergoes overcharging. This document examines two protection strategies employing a proportional–integral (PI) controller to manage the transient rotor current and mitigate DC-link overcharging, thereby optimizing DFIG behavior during network faults. One option combines a classic crowbar circuit with a DC-chopper, while the other is a modified protection scheme (MPS) that includes an impedance with passive elements and a crowbar. The impedance forms a resistance Rp parallel with an inductance Lp. Both configurations, situated between the rotor coils and the rotor-side converter (RSC), augment the capacity for low-voltage ride-through (LVRT). MATLAB/SIMULINK simulations of the two schemes demonstrate successful rotor current reduction at 2.9 kA and 3.4 kA, and DC-link tension reduction below and at 1.4 KV. In addition, the conventional crowbar and MPS configurations efficiently restrict the RSC current to levels below 0.21 kA and 2.94 kA, while absorbing up to 2.52 kA and 1.52 kA, respectively. The key difference lies in the fact that fine-tuning the parameters in the MPS design prevents rotor disconnection when faced with a balanced fault. This enhancement enhances machine performance and enables full stator power control via the RSC.

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Suther, Bradley E., David S. Leigh, and Larry T. West. "Soil Chemistry and Clay Mineralogy of an Alluvial Chronosequence from the North Carolina Sandhills of the Upper Coastal Plain, USA." Soil Systems 6, no. 1 (December 23, 2021): 1. http://dx.doi.org/10.3390/soilsystems6010001.

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Temporal changes in soil development were assessed on fluvial terraces of the Little River in the upper Coastal Plain of North Carolina. We examined five profiles from each of six surfaces spanning about 100,000 years. Soil-age relationships were evaluated with inter-surface clay mineral comparisons and regression of chemical properties versus previously reported optically-stimulated luminescence ages using the most developed subsoil horizon per profile. Bases to alumina (Bases/Al2O3) ratios have negative correlations with age, whereas dithionite-Fe (FeD) concentrations are positively correlated with time and differentiate floodplain (<200 yr BP) from terrace (≥10 ± 2 ka) soils and T4 pedons (75 ± 10 ka) from younger (T1-T3b, 10 ± 2–55 ± 15 ka) and older (T5b, 94 ± 16 ka) profiles. Entisols develop into Ultisols with exponentially decreasing Bases/Al2O3 ratios, reflecting rapid weatherable mineral depletion and alumina enrichment during argillic horizon development in the first 13–21 kyr of pedogenesis. Increasing FeD represents transformation and illuviation of free Fe inherited from parent sediments. Within ~80–110 kyr, a mixed clay mineral assemblage becomes dominated by kaolinite and gibbsite. Argillic horizons form by illuviation, secondary mineral transformations, and potentially, a bioturbation-translocation mechanism, in which clays distributed within generally sandy deposits are transported to surface horizons by ants and termites and later illuviated to subsoils. T5b profiles have FeD concentrations similar to, and gibbsite abundances greater than, those of pedons on 0.6–1.6 Ma terraces along Coastal Plain rivers that also drain the Appalachian Piedmont. This is likely because the greater permeability and lower weatherable mineral contents of sandy, Coastal Plain-sourced Little River alluvium favor more rapid weathering, gibbsite formation, and Fe translocation than the finer-grained, mineralogically mixed sediments of Piedmont-draining rivers. Therefore, recognizing provenance-related textural and mineralogical distinctions is crucial for evaluating regional chronosequences.

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Gulyás, Sándor, and Pál Sümegi. "Late Pleistocene to Holocene Palaeohydrological History of the Thermal-Spring-Fed Lake Pețea (NW Romania) Revealed by Radiocarbon Dating and Complex Sedimentological Investigations." Quaternary 6, no. 2 (June 12, 2023): 37. http://dx.doi.org/10.3390/quat6020037.

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Understanding sedimentation processes in response to past hydrogeological and climatic changes and capturing millennial-scale variations is a key focus of lacustrine paleoenvironmental research. This study presents the first high-resolution chronology and sedimentary data for the small thermal-spring-fed Lake Pețea, NW Romania, and unravels the evolutionary history of the lake harboring a unique endemic fauna. Its small size and single source of water make it particularly sensitive to hydrological changes. In the recent past, over-exploitation of the thermal water has led to the complete drying up of the lake and the extinction of its fauna. Nevertheless, past spatio-temporal variation of environmental factors, in particular the fluctuation of lake levels and water temperature, must have had a significant impact on the survival and evolution of the endemic mollusk fauna. This fact makes this study particularly important. Based on our results, a three-stage sedimentary evolution occurred, mainly controlled by major climate-driven hydrological changes also seen in regional records, i.e., 17.5–14.5 ka shallow eutrophic lake, 14.5–5.5 ka oligotrophic carbonate-rich lake, and 5.5–0.5 ka shallow eutrophic lake. A major lowstand at 11.7–10.2 ka due to drier climate was followed by progressively rising water levels up to 5 ka followed by a drop. The main control on lake level fluctuations and sedimentary phases was the varying input of thermal water due to recurring increased/decreased recharge of the underground shallow karst water system. The driving factor of thermal water discharge was different during the Late Glacial than the Holocene. It was the warming of the climate at 14.5 ka cal BP and melting of regional ice sheets in addition to increased precipitation that created an oligotrophic lake by recharging the underground thermal water system. Conversely, during the Holocene, increasing/decreasing moisture availability driven by major climate forcings was in control of thermal water recharge, erosion, and fluctuating lake levels.

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Carpenter, P., and J. Armstrong. "Analyzing Mg and Fe in Olivines, Pyroxenes, and Garnets: Systematic Discrepancies." Microscopy and Microanalysis 4, S2 (July 1998): 224–25. http://dx.doi.org/10.1017/s1431927600021243.

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Quantitative analysis of Mg and Fe in olivines, pyroxenes, and garnets is important for geochemical studies. Natural olivines have compositions close to the forsterite (Mg2SiO4) and fayalite (Fe2SiO4) binary system, with relatively minor substitution of other components. Pyroxenes and garnets are problematic in that they exhibit more diverse solid solution, and may contain both Fe2+ and Fe3+, the relative concentrations of which cannot be directly measured with the microprobe. The forsterite-fayalite olivine binary is a convenient system for studying the accuracy of Mg and Fe analysis without other complicating factors.Bence and Albee utilized the a-factor approach for quantitative analysis of silicates, based on the empirical observation:where CA,AB is the weight fraction of the oxide A in a binary oxide system AB, and KA,AB is the measured x-ray intensity of A relative to that of the pure oxide A.

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McCleary, J., Ming-Yi Li, and Kai Chang. "Ka-band slot-fed higher order-mode low-loss Fabry-Perot filters." IEEE Transactions on Microwave Theory and Techniques 42, no. 7 (July 1994): 1423–26. http://dx.doi.org/10.1109/22.299740.

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Han, C., J. Huang, and K. Chang. "Cassegrain Offset Subreflector-Fed X/Ka Dual-Band Reflectarray With Thin Membranes." IEEE Transactions on Antennas and Propagation 54, no. 10 (October 2006): 2838–44. http://dx.doi.org/10.1109/tap.2006.882176.

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Jung, Young-Bae, and Seong-Ook Park. "Ka-Band Shaped Reflector Hybrid Antenna Illuminated by Microstrip-Fed Horn Array." IEEE Transactions on Antennas and Propagation 56, no. 12 (December 2008): 3863–67. http://dx.doi.org/10.1109/tap.2008.2007402.

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Song, Bin, Glen S. Kurokawa, Shuang Liu, and Chris Orvig. "Proton- and lanthanide-coordinating properties of the tetraaza macrocycle (EDDA-KA)2 in aqueous solution." Canadian Journal of Chemistry 79, no. 5-6 (May 1, 2001): 1058–67. http://dx.doi.org/10.1139/v00-179.

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The new potentially multidentate ligand (EDDA-KA)2 has been prepared and its acid-base properties determined. Its coordination properties with three lanthanide ions (La3+, Gd3+, and Lu3+) and Fe3+ have been studied in aqueous solution (I = 0.16 M NaCl, 25°C) by potentiometric pH, spectrophotometric, and 1H NMR titrations. In total, eight pKa values could be determined by these diverse methods. From the 1H NMR titrations, all the deprotonation steps could be determined and assigned (in groups). Strong hydrogen bonding among two nitrogen atoms and one oxygen atom on the pyrone ring was observed, and the corresponding pKa values were estimated to be 13.2 and 14.0. By comparison with similar systems, an equilibrium constant for the formation of the hydrogen bond was estimated, KI = 104.4. Eight stability constants in total were determined for various protonation states of the La3+ and Gd3+ complexes, but for Lu3+ only the last four constants were obtained. The species distribution diagram showed that [M(EDDA-KA)2-4H]2- predominated in the range 5 [Formula: see text] pH [Formula: see text] 9 and [M(EDDA-KA)2-6H]4- predominated in the region 9 [Formula: see text] pH [Formula: see text] 11. In the former complex, two strong hydrogen bonds anchored the macrocycle and Ln3+ was coordinated with the four carboxylate groups; in the latter, the two hydrogen bonding protons were absent and the metal ion might also bind to the nitrogens on the macrocycle. The stability of Gd3+-(EDDA-KA)2 is lower than the analogous Gd3+ complexes of DOTA, DTPA, and DTPA-BMA.Key words: acidity constants, stability constants, La3+, Gd3+, Lu3+, Fe3+, amino carboxylate chelator.

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Kandwal, A. "Compact Dual Band Antenna Design for Ku / Ka Band Applications." Advanced Electromagnetics 6, no. 4 (October 21, 2017): 1–5. http://dx.doi.org/10.7716/aem.v6i4.450.

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This communication proposes a compact 16 GHz / 30 GHz dual band antenna design for Ku / Ka band applications. The antenna consists of two layers with lower layer having the fed patch and the upper layer having non-periodic element array. The antenna has been designed to operate at two different frequencies with compact dimensions of (8mm x 8mm) using Rogers RT 5880. The compact size of this proposed antenna also makes it suitable for integration with the microwave and millimeter wave circuits. The proposed antenna provides high radiation efficiency and a peak gain of about 8 dB at the resonant frequencies with reduced side lobe levels.

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Wang, Dong-Tao, Lu Lu, Ying Shi, Zhen-Bo Geng, Yi Yin, Ming Wang, and Lian-Bo Wei. "Supplementation of ketoacids contributes to the up-regulation of the Wnt7a/Akt/p70S6K pathway and the down-regulation of apoptotic and ubiquitin–proteasome systems in the muscle of 5/6 nephrectomised rats." British Journal of Nutrition 111, no. 9 (February 6, 2014): 1536–48. http://dx.doi.org/10.1017/s0007114513004091.

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Ketoacids (KA) are known to improve muscle mass among patients with chronic kidney disease (CKD) on a low-protein diet (CKD-LPD), but the mechanism of its preventive effects on muscle atrophy still remains unclear. Since muscle atrophy in CKD may be attributable to the down-regulation of the Wnt7a/Akt/p70S6K pathway and the activation of the ubiquitin–proteasome system (UPS) and the apoptotic signalling pathway, a hypothesis can readily be drawn that KA supplementation improves muscle mass by up-regulating the Wnt7a/Akt/p70S6K pathway and counteracting the activation of the UPS and caspase-3-dependent apoptosis in the muscle of CKD-LPD rats. Rats with 5/6 nephrectomy were randomly divided into three groups, and fed with either 22 % protein (normal-protein diet; NPD), 6 % protein (LPD) or 5 % protein plus 1 % KA for 24 weeks. Sham-operated rats with NPD intake were used as the control. The results demonstrated that KA supplementation improved protein synthesis and increased related mediators such as Wnt7a, phosphorylated Akt and p70S6K in the muscle of CKD-LPD rats. It also inhibited protein degradation, withheld the increase in ubiquitin and its ligases MAFbx (muscle atrophy F-box) and MuRF1 (muscle ring finger-1) as well as attenuated proteasome activity in the muscle of CKD-LPD rats. Moreover, KA supplementation gave rise to a reduction in DNA fragment, cleaved caspase-3 and 14 kDa actin fragment via the down-regulation of the Bax:Bcl-2 ratio in the muscle of CKD-LPD rats. The beneficial effects unveiled herein further consolidate that KA may be a better therapeutic strategy for muscle atrophy in CKD-LPD.

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Yaqin, Achmad, Azwar Manaf, Iwan Sugihartono, Yana Taryana, and Yuda Zainal. "Increased Reflection Loss of SrFe(11.9-x) In0.1Snx/2Znx/2O19 (x = 0.0; 0.10; 0.35 and 0.50): A Microwave Absorber Induced by Reduced Coercivity." Key Engineering Materials 940 (January 30, 2023): 47–54. http://dx.doi.org/10.4028/p-amgj8y.

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In this study, an increase in the reflection loss (RL) value for SrFe(11.9-x)In0.1Snx/2Znx/2O19 samples (x = 0; 0.10; 0.35 and 0.50) is reported. The X-ray diffraction (XRD) pattern of all samples confirmed that the SrFe(11.9-x)In0.1Snx/2Znx/2O19 samples (x = 0, 0.10, 0.35, and 0.50) posses polycrystalline with single phase. We have demonstrated that co-substitution of Zn2+ and Sn4+ ions with a fraction of x = 0.10 reduced the coercivity of the pure nano strontium hexaferrite (SHF) from 346.80 kA/m to 50.34 kA/m. The substitution of Fe3+ ion by Sn2+ and Zn4+ affect the coercivity decreased significantly. Meanwhile, the saturation magnetization and remanence slightly decreases. Hence, the decreasing of coercivity cause the reflection loss (RL) increase from -16.43 dB to -25.62 dB. We believed the RL value can be increased efficiently by reducing the coercivity of the sample obtained by co-substitution of Zn2+ and Sn4+ ions to Fe3+ in the main phase of SrFe11.9In0.1O19.

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Han, C., J. Huang, and Kai Chang. "A high efficiency offset-fed X/ka-dual-band reflectarray using thin membranes." IEEE Transactions on Antennas and Propagation 53, no. 9 (September 2005): 2792–98. http://dx.doi.org/10.1109/tap.2005.854531.

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Kadri, I., A. Petosa, and L. Roy. "Ka-band Fresnel lens antenna fed with an active linear microstrip patch array." IEEE Transactions on Antennas and Propagation 53, no. 12 (December 2005): 4175–78. http://dx.doi.org/10.1109/tap.2005.859994.

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Jaschke, Thomas, Hans K. Mitto, and Arne F. Jacob. "K/Ka-band dual-polarized SIW-fed lens antennas for Rx/Tx integration." International Journal of Microwave and Wireless Technologies 10, no. 5-6 (April 3, 2018): 627–34. http://dx.doi.org/10.1017/s1759078718000399.

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AbstractThis contribution deals with array elements for K/Ka-band satellite communication terminals. It proposes an end-fire design realized in substrate integrated waveguide technology and featuring dual-band functionality, and dual circular polarization. The latter is achieved by means of a dual-band orthomode transducer. An extended hemispherical dielectric lens ensures good matching and radiation properties. The feed structure is composed of a multilayer printed circuit board and tapered superstrates. The design procedure of the components is explained in detail and three different variants of the antenna are compared. The measured scattering and far-field parameters validate the concept.

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Selis, Elyas F., Maria Paulina I. Ceme, Maria R. Mue, Yaltiana Laurensa, Patrisius Adja Bhia, Maria A. Asti, Maria F. M. Nenu, and Yasinta Maria Fono. "PENGARUH TARIAN TRADISIONAL SEPA API TERHADAP KEHIDUPAN SOSIAL MASYARAKAT PAUTOLA KECAMATAN KEO TENGAH, KABUPATEN NAGEKEO." Jurnal Citra Pendidikan Anak 2, no. 1 (March 8, 2023): 110–20. http://dx.doi.org/10.38048/jcpa.v2i1.1619.

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Penelitian ini bertujuan untuk mendeskripsikan tarian sepa api dalam ritual adat Ka Todo yang artinya upacara makan yang dilakukan oleh tua-tua adat dari dua suku yang dilakukan didepan rumah adat yang disebut Enda, yakni suku Pau dan suku Toda yang menunjukan simbol atau makna yang terdapat dalam ritual tersebut. Adapun masalah yang terdapat dalam ritual tersebut yakni (1.) apa yang melatarbelakangi munculnya tarian sepa api pada etnik Pautola, Keo Tengah. (2.) apa saja tahapan-tahapan dalam melakukan tarian sepa api. (3.) apa yang menjadi pengaruh tarian sepa api terhadap kehidupan masyarakat pautola. Adapun tujuan dan manfaat yang terdapat dalam tarian sepa api. Pendekatan yang digunakan dalam penelitian ini adalah pendekatan deskriptif kualitatif. Data dikumpulkan dengan menggunakan metode simak dan metode rekam sedangkan teknik yang digunakan ialah teknik wawancara, teknik catat dan teknik dokumentasi. Teori yang digunakan dalam penelitian ini adalah teori relativisme. Hasil analisis menunjukan bahwa dalam traian sepa api terdapat 13 tahapan yakni (1) wuku niu, (2) ka ngagha, (3) ka todo, (4) ndera, (5) daka ana, (6) jetu, (7) wi tuka dako, (8) bele wo, (9) ade tadi, (10) oa api, (11) sepa api, (12) papa todi, (13) ka fai nggae. Adapun makna pada simbol tarian sepa api yaitu makna religius, makna sosial, makna kekuatan, dan makna hiburan.

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Zhai, Yu, Ding Xu, and Yan Zhang. "Ka-Band Lightweight High-Efficiency Wideband 3D Printed Reflector Antenna." International Journal of Antennas and Propagation 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/7360329.

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This paper presents a lightweight, cost-efficient, wideband, and high-gain 3D printed parabolic reflector antenna in the Ka-band. A 10 λ reflector is printed with polylactic acid- (PLA-) based material that is a biodegradable type of plastic, preferred in 3D printing. The reflecting surface is made up of multiple stacked layers of copper tape, thick enough to function as a reflecting surface (which is found 4 mm). A conical horn is used for the incident field. A center-fed method has been used to converge the energy in the broadside direction. The proposed antenna results measured a gain of 27.8 dBi, a side lobe level (SLL) of −22 dB, and a maximum of 61.2% aperture efficiency (at 30 GHz). A near-field analysis in terms of amplitude and phase has also been presented which authenticates the accurate spherical to planar wavefront transformation in the scattered field.

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Roger, Jonathan, Francky Saint-Ange, Patrick Lajeunesse, Mathieu J. Duchesne, and Guillaume St-Onge. "Late Quaternary glacial history and meltwater discharges along the Northeastern Newfoundland Shelf." Canadian Journal of Earth Sciences 50, no. 12 (December 2013): 1178–94. http://dx.doi.org/10.1139/cjes-2013-0096.

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The geomorphology of the Eastern Canadian margin has been shaped by glacial processes during the Quaternary. Many studies have focused on the ice-sediment pathway through Hudson Strait to reconstruct the dynamics of the Laurentide Ice Sheet, and as a consequence, little is known on its marginal ice domes. Here we reconstruct the dynamics of two trough mouth fans (TMFs) offshore NE Newfoundland using sediment cores and radiocarbon ages supported by very high resolution seismic reflection profiles. These two TMFs, namely Notre Dame and Hawke, are fed by two glacial troughs incised in the bedrock. The TMFs show a complete sedimentary sequence from 30 ka BP to the beginning of the Holocene. The sampled sedimentary record on the upper slope extends back to a thick Heinrich event 3 (H3) deposit that corresponds to the end of the maximum extent of the Newfoundland ice dome. Above H3, a thick succession of turbidite deposits (>10 m) observed in both TMFs is correlated with periods of major meltwater supply from 28–29 to 17 ka BP. Our results show that the Last Glacial Maximum (LGM) period was characterized by major input of meltwater events stemming from the Newfoundland dome. The presence of H1 (∼17 ka BP) coincide with the end of the turbidite activity which is replaced by an open-water environment characterized by hemipelagic sediments rich in ice-rafted debris. The proglacial muddy sediment older than 13.3 ka BP on the shelf shows that ice was not grounded after H1, suggesting a very rapid retreat of the ice on the Newfoundland shelf after 17 ka BP.

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Zhang, Feifei, Qi Gao, Junxia Zhao, Man Ge, and Yinjuan Bai. "Design and synthesis of a novel rhodamine-based chemosensor and recognition study to Fe3+." Heterocyclic Communications 22, no. 1 (February 1, 2016): 37–42. http://dx.doi.org/10.1515/hc-2015-0139.

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AbstractA fluorescent and colorimetric chemosensor Rh1 for Fe3+ was synthesized by condensation reaction of rhodamine B hydrochloride and 2-aminothiazole, and its structure was confirmed by NMR, IR, HRMS and crystal data. Upon coordination with Fe3+ in CH3CN-H2O (1:1, v/v) solution, the spirolactam of Rh1 is opened, which results in a dramatic enhancement of fluorescence intensity as well as the color change of the solution. Most importantly, other metal ions show no obvious interference with the detection of Fe3+. Under the optimum conditions described, the fluorescence intensity is linearly proportional to the concentration of Fe3+ in the range of 2 μm ~ 7 μm. The Job’s plot indicates a 1:1 binding stoichiometry between Rh1 and Fe3+. The association constant (Ka) is 2.26 × 104m-1.

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BALLANTYNE, Colin K., and David SMALL. "The Last Scottish Ice Sheet." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 110, no. 1-2 (May 15, 2018): 93–131. http://dx.doi.org/10.1017/s1755691018000038.

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ABSTRACTThe last Scottish Ice Sheet (SIS) expanded from a pre-existing ice cap after ∼35 ka. Highland ice dominated, with subsequent build-up of a Southern Uplands ice mass. The Outer Hebrides, Skye, Mull, the Cairngorms and Shetland supported persistent independent ice centres. Expansion was accompanied by ice-divide migration and switching flow directions. Ice nourished in Scotland reached the Atlantic Shelf break in some sectors but only mid-shelf in others, was confluent with the Fennoscandian Ice Sheet (FIS) in the North Sea Basin, extended into northern England, and fed the Irish Sea Ice Stream and a lobe that reached East Anglia. The timing of maximum extent was diachronous, from ∼30–27 ka on the Atlantic Shelf to ∼22–21 ka in Yorkshire. The SIS buried all mountains, but experienced periods of thickening alternating with drawdown driven by ice streams such as the Minch, the Hebrides and the Moray Firth Ice Streams. Submarine moraine banks indicate oscillating retreat and progressive decoupling of Highland ice from Orkney–Shetland ice. The pattern and timing of separation of the SIS and FIS in the North Sea Basin remain uncertain. Available evidence suggests that by ∼17 ka, much of the Sea of the Hebrides, the Outer Hebrides, Caithness and the coasts of E Scotland were deglaciated. By ∼16 ka, the Solway lowlands, Orkney and Shetland were deglaciated, the SIS and Irish Ice Sheet had separated, the ice margin lay along the western seaboard, nunataks had emerged in Wester Ross, the ice margin lay N of the Cairngorms and the sea had invaded the Tay and Forth estuaries. By ∼15 ka, most of the Southern Uplands, the Firth of Clyde, the Midland Valley and the upper Spey valley were deglaciated, and in NW Scotland ice was retreating from fjords and valleys. By the onset of rapid warming at ∼14.7 ka, much of the remnant SIS was confined within the limits of Younger Dryas glaciation. The SIS, therefore, lost most of its mass during the Dimlington Stade. It is uncertain whether fragments of the SIS persisted on high ground throughout the Lateglacial Interstade.

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Li, Yujian, Lei Ge, Junhong Wang, Bo Ai, Meie Chen, Zhan Zhang, and Zheng Li. "A $Ka$ -Band 3-D-Printed Wideband Stepped Waveguide-Fed Magnetoelectric Dipole Antenna Array." IEEE Transactions on Antennas and Propagation 68, no. 4 (April 2020): 2724–35. http://dx.doi.org/10.1109/tap.2019.2950868.

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Kim, Jeong-Wook, Seung-Won Oh, and Han Lim Lee. "Single-fed Ku/Ka dual-band aperture shared planar antenna array for satellite communication." Alexandria Engineering Journal 104 (October 2024): 235–45. http://dx.doi.org/10.1016/j.aej.2024.06.029.

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41

Pasaribu, M., Heroe Wijanto, and Budi Prasetya. "Determination of Operational Threshold for Coding and Modulation Combination to Improve The Quality of High Throughput Satellite in Ka-Band Frequency in Indonesia." Journal of Measurements, Electronics, Communications, and Systems 2, no. 1 (December 31, 2016): 9. http://dx.doi.org/10.25124/jmecs.v2i1.1483.

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The vast enhancement of telecommunication technology has encouraged the increase of demand for more satellite capacity. HTS in Ka-Band frequency, that can deliver more capacity up to 50 GHz, can be a solution. Unfortunately, Ka-Band is susceptible to rain attenuation which is potentially difficult to be implemented in Indonesia because of its high rain rate. But, According to the previous research by Suwadi, Marrudani, and Lye, the combination of coding and modulation technique can be used as a solution to improve the performance of service dealing with rain attenuation. In this research, the writer will try to improve whether the combination of coding and modulation is also able to improve HTS Ka-Band communication link here ini in Indonesia with the high rain rate per year and to determine threshold of which the combination of coding and modulation that is best suited to each weather condition, in order to get the minimum required performance with BER min = 10 âˆ’ 8. The conclusion of this research shows that the quality of HTS in Ka-Band frequency in Indonesia with BER = 10 âˆ’ 8 can be improved by using QPSK, 8-APSK, 16-APSK, and 9 types of FEC. Furthermore, the 17 pairs of ModCod can be categorized into 8 thresholds that will determine with that ModCod that should be used in order to get the link quality of BER = 10 âˆ’ 8 for each certain rain condition.

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Gao, Xiang, Jianxiang Wu, Zheyi Dong, Can Hua, Huimin Hu, and Changlin Mei. "A low-protein diet supplemented with ketoacids plays a more protective role against oxidative stress of rat kidney tissue with 5/6 nephrectomy than a low-protein diet alone." British Journal of Nutrition 103, no. 4 (November 2, 2009): 608–16. http://dx.doi.org/10.1017/s0007114509992108.

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Dietary protein restriction is one major therapy in chronic kidney disease (CKD), and ketoacids have been evaluated in CKD patients during restricted-protein diets. The objective of the present study was to compare the efficacy of a low-protein diet supplemented with ketoacids (LPD+KA) and a low-protein diet alone (LPD) in halting the development of renal lesions in CKD. 5/6 Nephrectomy Sprague–Dawley rats were randomly divided into three groups, and fed with either 22 % protein (normal-protein diet; NPD), 6 % protein (LPD) or 5 % protein plus 1 % ketoacids (LPD+KA) for 24 weeks. Sham-operated rats were used as controls. Each 5/6 nephrectomy group included fifteen rats and the control group included twelve rats. Proteinuria, decreased renal function, glomerular sclerosis and tubulointerstitial fibrosis were found in the remnant kidneys of the NPD group. Protein restriction ameliorated these changes, and the effect was more obvious in the LPD+KA group after 5/6 nephrectomy. Lower body weight and serum albumin levels were found in the LPD group, indicating protein malnutrition. Lipid and protein oxidative products were significantly increased in the LPD group compared with the LPD+KA group. These findings indicate that a LPD supplemented with ketoacids is more effective than a LPD alone in protecting the function of remnant kidneys from progressive injury, which may be mediated by ketoacids ameliorating protein malnutrition and oxidative stress injury in remnant kidney tissue.

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Zhai, Guohua, Yong Cheng, Qiuyan Yin, Shouzheng Zhu, and Jianjun Gao. "Simplified Printed Log-Periodic Dipole Array Antenna Fed by CBCPW." International Journal of Antennas and Propagation 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/548610.

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A novel simple approach for designing single-layer printed log-periodic dipole array (PLPDA) antenna fed by conductor-backed coplanar waveguide (CBCPW) is presented. The PLPDA antenna has the merits of wide bandwidth, low profile, and stable radiation pattern, which should be fed by the balanced line. The balanced line, created by the geometric features of the CBCPW, provides a balun with a considerably wide bandwidth with low profile, broad bandwidth, low insertion loss, and so forth. The prototype of the proposed CBCPW-fed printed log-periodic array at Ka band is designed and fabricated; the measured data are in good agreement with the simulated results.

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Zhang, H. H., M. J. Luo, Q. W. Zhang, P. M. Cai, A. Idrees, Q. E. Ji, J. Q. Yang, and J. H. Chen. "Molecular characterization of prophenoloxidase-1 (PPO1) and the inhibitory effect of kojic acid on phenoloxidase (PO) activity and on the development ofZeugodacus tau(Walker) (Diptera: Tephritidae)." Bulletin of Entomological Research 109, no. 2 (June 22, 2018): 236–47. http://dx.doi.org/10.1017/s0007485318000470.

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AbstractPhenoloxidase (PO) plays a key role in melanin biosynthesis during insect development. Here, we isolated the 2310-bp full-length cDNA of PPO1 fromZeugodacus tau, a destructive horticultural pest. qRT-polymerase chain reaction showed that theZtPPO1transcripts were highly expressed during larval–prepupal transition and in the haemolymph. When the larvae were fed a 1.66% kojic acid (KA)-containing diet, the levels of theZtPPO1transcripts significantly increased by 2.79- and 3.39-fold in the whole larvae and cuticles, respectively, while the corresponding PO activity was significantly reduced; in addition, the larval and pupal durations were significantly prolonged; pupal weights were lowered; and abnormal phenotypes were observed. Anin vitroinhibition experiment indicated that KA was an effective competitive inhibitor of PO inZ. tau. Additionally, the functional analysis showed that 20E could significantly up-regulate the expression ofZtPPO1, induce lower pupal weight, and advance pupation. Knockdown of theZtPPO1gene by RNAi significantly decreased mRNA levels after 24 h and led to low pupation rates and incomplete pupae with abnormal phenotypes during the larval-pupal interim period. These results proved that PO is important for the normal growth ofZ. tauand that KA can disrupt the development of this pest insect.

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Sharma, Hemanti, Sebastian G. Mutz, and Todd A. Ehlers. "The effects of late Cenozoic climate change on the global distribution of frost cracking." Earth Surface Dynamics 10, no. 5 (October 25, 2022): 997–1015. http://dx.doi.org/10.5194/esurf-10-997-2022.

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Abstract. Frost cracking is a dominant mechanical weathering phenomenon facilitating the breakdown of bedrock in periglacial regions. Despite recent advances in understanding frost cracking processes, few studies have addressed how global climate change over the late Cenozoic may have impacted spatial variations in frost cracking intensity. In this study, we estimate global changes in frost cracking intensity (FCI) by segregation ice growth. Existing process-based models of FCI are applied in combination with soil thickness data from the Harmonized World Soil Database. Temporal and spatial variations in FCI are predicted using surface temperature changes obtained from ECHAM5 general circulation model simulations conducted for four different paleoclimate time slices. Time slices considered include pre-industrial (∼ 1850 CE, PI), mid-Holocene (∼ 6 ka, MH), Last Glacial Maximum (∼ 21 ka, LGM), and Pliocene (∼ 3 Ma, PLIO) times. Results indicate for all paleoclimate time slices that frost cracking was most prevalent (relative to PI times) in the middle- to high-latitude regions, as well as high-elevation lower-latitude areas such the Himalayas, Tibet, the European Alps, the Japanese Alps, the US Rocky Mountains, and the Andes Mountains. The smallest deviations in frost cracking (relative to PI conditions) were observed in the MH simulation, which yielded slightly higher FCI values in most of the areas. In contrast, larger deviations were observed in the simulations of the colder climate (LGM) and warmer climate (PLIO). Our results indicate that the impact of climate change on frost cracking was most severe during the PI–LGM period due to higher differences in temperatures and glaciation at higher latitudes. The PLIO results indicate low FCI in the Andes and higher values of FCI in Greenland and Canada due to the diminished extent of glaciation in the warmer PLIO climate.

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Sun, Zhongxiu, Siyi Duan, Yingying Jiang, Qiubing Wang, and Ganlin Zhang. "Dominant Aggregate Binding Agent Dynamics of Quaternary Ancient Red Soils under Different Land Use Patterns." Agronomy 13, no. 6 (June 9, 2023): 1572. http://dx.doi.org/10.3390/agronomy13061572.

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The cementation mechanisms and processes of aggregate binding agents are important in understanding aggregate formation. However, the role of threshold values and the proportions of organic and inorganic binding agents in aggregate formation remain unclear. This research investigated the dominant aggregate binding agent dynamics in a sequence comprising buried ancient red soil unaffected by modern climate changes and human activities, alongside nearby exposed Quaternary ancient red soils subjected to different land use patterns influenced by these factors in northeastern China. By analyzing soil age, aggregate compositions, and organic/inorganic indicators of binding agents, including soil organic matter (SOM), free iron oxide (Fed), poorly crystalline iron oxide (Feo), crystalline iron oxide (Fed-Feo), and total clay particles (TCL), we determined the relative contributions of different binding agents using redundancy analysis (RDA). The results revealed that the buried ancient red soil did not contain dominant binding agents in the aggregate formation before 91.01 ka BP. Due to denudation, the buried ancient red soil was exposed at the surface and experienced the importation of soil organic matter, weathering of silicate-bound iron oxides, and crystallization of poorly crystalline iron oxides resulting from the effects of different land use patterns from 91.01 ka to the present. Under the influence of binding agent dynamics, dominant binding agents in the exposed Quaternary ancient red soils’ aggregate formation changed into SOM and Fed. When the C/(Fed-Feo) molar ratio was less than 2.13, Fed-Feo was the dominant aggregate binding agent. When the C/(Fed-Feo) molar ratio was greater than 2.13, SOM was the dominant aggregate binding agent. The results of this study improve our understanding of aggregate formation and the relationship between soil organic matter and iron oxides.

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Pouclet, André, Etienne Juvigné, and Stéphane Pirson. "The Rocourt Tephra, a Widespread 90–74 ka stratigraphic marker in Belgium." Quaternary Research 70, no. 1 (July 2008): 105–20. http://dx.doi.org/10.1016/j.yqres.2008.03.010.

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AbstractA new study of the stratigraphy and composition of the Rocourt Tephra is performed at five sites in Belgium and brackets the age of the tephra between 90.3 and 74 ka. The volcanic glass grains have a typical shape of phreatomagmatic eruption products. A large set of tephra minerals were analyzed, namely clinopyroxene, orthopyroxene, amphibole, and Cr-spinel. The compositions of these minerals have been compared with the lava xenocrysts, megacrysts, and phenocrysts of the proximate Eifel volcanic province for which the origin has been determined (mantle xenoliths, high-pressure cumulates, and middle- to low-pressure magmatic phases). This allowed us to determine the likely origin of the tephra minerals. The Rocourt Tephra source could be a West Eifel volcano that was fed by a deep-seated magma batch rich in high- to middle-pressure minerals.

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Moir, A. M., and V. A. Zammit. "Changes in the properties of cytosolic acetyl-CoA carboxylase studied in cold-clamped liver samples from fed, starved and starved-refed rats." Biochemical Journal 272, no. 2 (December 1, 1990): 511–17. http://dx.doi.org/10.1042/bj2720511.

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We have used the cold-clamping technique to study the changes in acetyl-CoA carboxylase activity that occur in the cytosolic and mitochondrial fractions of the liver of fed, starved and starved-refed rats. No evidence was found for a role of the mitochondrial enzyme as a pool from which cytosolic carboxylase could be replenished upon refeeding of starved rats. Starvation for 24 h or 48 h induced changes in the expressed (assayed at 20 mM-citrate), total (citrate- and phosphatase-treated) and citrate-independent activities of cytosolic carboxylase, as well as in its Ka for citrate. The expressed/total activity ratio was low even in the fed state and was depressed further by starvation. The effects of refeeding occurred in two phases: an acute phase (approx. 1 h) in which the starvation-induced changes in Ka and expressed/total activity ratio were rapidly reversed, and a prolonged slow phase in which the two parameters attained values that were lower and higher, respectively, than those in the normal fed state. Refeeding also resulted in a gradual increase in citrate-independent activity of acetyl-CoA carboxylase. An additional marked increase in this activity occurred only in 48 h-starved-refed rats between 24 h and 48 h of refeeding. These findings are discussed in terms of the observed time courses of changes in lipogenic rates that occur in vivo in starved-refed rats and of the possible molecular mechanisms involved.

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Hsu, Shih-Hsun, Chulmin Han, John Huang, and Kai Chang. "An Offset Linear-Array-Fed Ku/Ka Dual-Band Reflectarray for Planet Cloud/Precipitation Radar." IEEE Transactions on Antennas and Propagation 55, no. 11 (November 2007): 3114–22. http://dx.doi.org/10.1109/tap.2007.908841.

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Arnaud, Eric, Régis Chantalat, Thierry Monediere, Emmanuel Rodes, and Marc Thevenot. "Achievements on circularly polarized horn-fed metallic electromagnetic band gap antenna design." International Journal of Microwave and Wireless Technologies 5, no. 4 (February 7, 2013): 507–20. http://dx.doi.org/10.1017/s1759078713000019.

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Abstract:

This paper presents a comprehensive study on the design of a 30 GHz, circularly polarized (CP), single horn-fed, metallic electromagnetic band gap (EBG) antenna. Three different approaches have been studied in order to create a 20 dBi antenna with an axial ratio (AR) lower than 1 dB over a 500 MHz bandwidth. Based on theoretical and experimental results, a conclusion is given on the best solution to obtain the desired characteristics. Perspectives and guidelines are also given for the design of multi-feed EBG antenna as a reflector focal feed for Ka-Band Space Applications.

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Journal articles on the topic 'Ka fei'

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