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Losing half the crown hardly affects the stem growth of a xeric southern beech population
Abstract Globally, forest ecosystems face increasing climate warming-driven stress. Crown dieback is commonly used as an indicator of declining tree vitality and is closely related to reduced stem radial growth rates. In a xeric northern Patagonian Nothofagus pumilio population, in which the majority of trees possess damaged crowns, we explored the relationship between percent crown damage and growth trends (basal area increment, BAI), interannual growth variability, and the climate sensitivity of growth. The majority of trees show stable BAI since about 1940 despite 5 to > 50% crown damage, which ranges from dieback of small branches to the presence of decades-old snagged branches. A minority of trees with more severe crown damage (> 50 to 95%) show continued growth decline during the last 80 years, but have not yet died. Crown damage was the best predictor of the BAI trend which turned negative at about 50% damage. Stronger damaged trees showed a higher growth sensitivity to summer heat and drought. Thus, the health of this population is apparently not threatened by crown damage up to 50%. Rather, trees might profit from the reduced foliage area, allowing them to stabilize their water relations and maintain stable but fairly slow growth in a drying climate.
Influence of wetting-drying cycles on the shear strength behavior of electroosmotically treated soft clay
Multicenter study on predicting postoperative upper limb muscle strength improvement in cervical spinal cord injury patients using radiomics and deep learning
Altered angular gyrus activation during the digit symbol substitution test in people living with HIV: beyond information processing speed deficits
Efficacy and safety of brolucizumab every 6 weeks induction therapy for neovascular age-related macular degeneration
Multimodal surface-based transformer model for early diagnosis of Alzheimer’s disease
3D computed tomography-dacryocystography (3D CT-DCG) and the contrast agents: direct comparison of Lipiodol and barium sulfate
Accuracy of blood heparin-binding protein (HBP) for diagnosis bacteremia in patients with sepsis
An enhanced walrus optimization algorithm for flexible job shop scheduling with parallel batch processing operation
Circularly-polarized 28-GHz antenna for next generations of communication systems
Abstract A circularly-polarized (CP) printed antenna is proposed for millimeter-wave mobile communications. The antenna has a defected ground structure (DGS), and it operates at 28 GHz. The geometries of the antenna on the upper surface and the DGS are symmetric about a $$45^\circ$$ -diagonal to produce perfect circular polarization. The antenna is fed through a three-stage microstrip line that acts as an impedance transformer for perfect matching of the antenna impedance to $$50\,{\Omega\:}$$ at $$28\:\text{G}\text{H}\text{z}$$ . The development of the antenna design is described in detail, starting with a square patch that is subjected to progressive geometrical modifications in the design stages to reach the final design of the patch antenna. The simulation results show that the antenna has a reflection coefficient magnitude of less than $$-35\:\text{d}\text{B}$$ at an axial ratio of less than 0.5 dB at 28 GHz. The technique used to generate the radiated circular polarized waves is demonstrated by investigating the surface current on the printed patch at the resonant frequency. The primary objective of the proposed design is not to produce a high-gain antenna, but rather to produce a low-profile planar antenna to serve as a building block for CP antenna systems such as multiple-input-multiple-output (MIMO) antennas, beam steering, and beamforming antenna arrays operating at 28 GHz. The designed antenna is fabricated and subjected to experimental evaluation. The numerical simulation results and the practical measurements came in good consent from the impedance matching and axial ratio (AR) of the radiated circular polarized wave perspectives. The input impedance is matched to the feeding line over a 1-GHz band, from 27.5 GHz to 28.5 GHz. The radiated wave is circularly polarized with AR less than 3 dB over about 0.4 GHz band starting from 27.8 GHz to 28.2 GHz. The peak gain of the designed antenna is 7 dBi and the radiation efficiency exceeds 90% all over the band of impedance matching. The performance of the antenna is compared with those of other antenna designs presented in some recent publications.
Polar bears and expanding sea ice in the Mid Holocene Aleutian Islands, Alaska
Parallel robotic automated docking method for realizing space segment assembly
Adverse obstetrical outcomes among adolescents in North Wollo Zone Governmental hospitals, Northern Ethiopia
Management of cardiovascular disease by cerium oxide nanoparticles via alleviating oxidative stress and adipokine abnormalities
Abstract The current study aimed to evaluate the role of cerium oxide nanoparticles (C-1), a potent antioxidant, in the medication of cardiovascular disease in obese animal model. C-1 was prepared using a modified sonication sol-gel method. Thirty-two adult male rats were equally divided into 4 groups (n=8/each). The first (control) and second (obese) groups are not treated while the obese rats in the third and fourth groups were given 15 and 30 mg/kg C-1(IP), respectively, for 8 weeks. Parameters of insulin resistance, adipocyte hormones, inflammatory markers, lipid profile, cardiac enzymes and cardiac iron content (C-Fe) were estimated. Moreover, histological study and immunohistochemical stain for inducible nitric oxide synthase (INOS) for cardiac and aortic tissues were performed. The XRD patterns of C-1 showed narrow symmetric diffraction peaks. The particle diameters were calculated from the TEM histogram (21.09 nm) and the Debye-Scherrer Method (20.74 nm) which were very similar. Using the most intense peak ( $$28.47^{\circ }$$ 28 . 47 ∘ ), structural parameters were calculated including nano-crystallite size, Micro-strain, Lorentz factor, Thomson polarization parameter, and Lorentz polarization parameter. BET was used to calculate The total surface area (S $$_{T}$$ T ), and specific surface area (S $$_{BET}$$ BET ). The XPS survey spectrum of C-1 showed peaks for C-1s, O-1s and Ce-3d. The treatment of obese rats with C-1 led to a significant decrease in body weight, C-Fe , plasma leptin, tumor necrosis factor-alpha (TNF $$\alpha$$ α ), interleukin-6 (IL6), C-reactive protein (CRP), resistin, cholesterol, triglycerides, low-density lipoprotein (LDL), Troponin, Creatinine Kinase-MB (CK-MB), lactate dehydrogenase (LDH), and malondialdehyde (MDA) in cardiac tissue or in plasma. Also, C-1 lowered plasma monocyte chemoattractant protein-1 (MCP-1), Epithelial Neutrophil-Activating Peptide (ENA-78), and insulin and glucose levels in obese rats. Furthermore, C-1 alleviated the increase of cardiac iNOS. Moreover, C-1 mitigated pathological changes of cardiac muscle and aorta observed in obese rats. On the other hand, C-1 enhanced adiponectin, cardiac glutathione (GSH) and superoxide dismutase (SOD) in obese rats. The effect of C-1 is dose-dependent ( 30 mg/kg of C-1 is more evident than 15 mg/kg). The modified synthesis method may lead to a smaller particle size than that reported in our previously reported work. The XRD patterns of C-1 indicate its cubic structure with space group F m -3 m (225) which was matched by code id 4343161 from COD. The Raman spectrum of C-1 indicates the absence of rearrangement oxygen atoms, the presence of oxygen in its fluorite lattice positions, and the oxygen vacancies in C-1 and the Ce vibration model (F2g). The presence of ten peaks in the high-resolution Ce-3d XP spectrum indicates the existence of both Ce3+ and Ce4+. C-1 showed therapeutic efficacy in atherosclerosis and cardiac muscle abnormalities associated with obese rats, probably because of their antioxidant and anti-inflammatory properties, which lead to lowering oxidative stress.