Central Lobe

2020 ◽  
Author(s):  
Keyword(s):  
Central Lobe

30 GHz Electronically Steerable Antennas Using BaxSr1−xTiO3-Based Room-Temperature Phase Shifters

1999 ◽  
Vol 603 ◽  
Author(s):  
C. M. Carlson ◽  
T. V. Rivkin ◽  
P. A. Parilla ◽  
J. D. Perkins ◽  
D. S. Ginley ◽  
...  
Keyword(s):  
Ferroelectric Phase ◽  
Beam Steering ◽  
Composite Films ◽  
Satellite Communications ◽  
Side Lobe ◽  
Phase Shifters ◽  
Temperature Phase ◽  
Central Lobe ◽  
Power Handling Capability ◽  
Half Power

AbstractWe report the performance of 16-element phased array antennas operating at 30 GHz and ambient temperature. These antennas use BaxSr1−xTiO3(BST)-based phase shifters to produce the beam steering. Ferroelectric phase shifters offer advantages over current semiconductor and ferrite devices including faster switching speeds and lower costs. Also, ferroelectric phase shifters offer higher power handling capability than semiconductor devices and also have high radiation resistance. We made phase shifters from laser-ablated epitaxial BST films as well as from polycrystalline BST-oxide composite films. Although neither the devices nor the materials themselves are fully optimized, phase shifters have shown > 360° of phase shift with < 350 V DC bias (E < 9 V/µm) and ∼8 dB insertion loss. With ferroelectric phase shifters incorporated, antennas show radiation patterns with central-lobe half-power widths of ∼13° and side lobe intensities down by more than 10 dB. Using the phase shifters, the central lobe can be shifted, or “steered,” by ±18° in either direction. These results demonstrate a first step toward a prototype steerable antenna for 20–30 GHz satellite communications as well as other applications.

Morphological and anatomical characterization of a new natural hybrid between Cohniella ascendens and C. brachyphylla (Oncidiinae: Orchidaceae)

Phytotaxa ◽  
2013 ◽  
Vol 144 (2) ◽  
pp. 45 ◽  
Author(s):  
WILLIAM CETZAL-IX ◽  
GERMAN CARNEVALI ◽  
ELIANA NOGUERA-SAVELLI ◽  
DAMELIS JAUREGUI
Keyword(s):  
Costa Rica ◽  
The Other ◽  
Natural Hybrid ◽  
Lateral Extension ◽  
Diagnostic Characters ◽  
Central Lobe ◽  
Cylindrical Column ◽  
Anatomical Characters ◽  
Column Base

A putative natural hybrid between Cohniella ascendens and C. brachyphylla (Orchidaceae, Oncidiinae) from western Costa Rica, C. ×francoi, is herein newly described, illustrated and characterized based upon both morphological and anatomical characters. This taxon hybrid is most similar to C. ascendens but the flowers show intermediate characters between the putative parents. Cohniella ×francoi is similar to C. ascendens in its semipendulous inflorescences, callus shape, cylindrical column base with linear oblong wings, and obovate stigmatic cavity plus several anatomical characters. On the other hand, it is similar to C. brachyphylla in the oblong to subquadrate lateral lobes of the labellum that are in the same plane as the central lobe, and the rectangular disc of the labellum with a lateral extension of the callus in the margins. A table of diagnostic characters for the new hybrid and its putative parents, a comparative figure, and a map showing their geographical distributions are also provided.  Cohniella ×francoi, un híbrido natural entre Cohniella ascendens y C. brachyphylla (Orchidaceae, Oncidiinae) del oeste de Costa Rica es aquí descrito, ilustrado y caracterizado por caracteres morfológicos y anatómicos. El nuevo híbrido es más similar a C. ascendens pero las flores presentan caracteres intermedios entre sus padres putativos. Cohniella ×francoi se parece a C. ascendens en la inflorescencia semipéndula, la forma del callo, la columna cilíndrica con las alas linear oblongas y la cavidad estigmática obovada, además de varios caracteres anatómicos. Por otro lado, es similar a C. brachyphylla por los lóbulos laterales del labelo oblongos a subcuadrados y extendidos en el mismo plano que el lóbulo central y el disco rectangular con extensiones laterales del callo en los márgenes. Adicionalmente, proporcionamos una tabla de caracteres diagnósticos para el nuevo híbrido y sus padres putativos, una figura comparativa y un mapa detallando las distribuciones geográficas de los tres taxones.

Protective effect of Ginkgo biloba extract on liver damage by a single dose of CCl 4 in male rats

2010 ◽  
Vol 30 (3) ◽  
pp. 209-216 ◽  
Author(s):  
RM Chávez-Morales ◽  
F. Jaramillo-Juárez ◽  
FA Posadas del Río ◽  
MA Reyes-Romero ◽  
ML Rodríguez-Vázquez ◽  
...  
Keyword(s):  
Steady State ◽  
Ginkgo Biloba ◽  
State Level ◽  
Ginkgo Biloba Extract ◽  
Male Rats ◽  
Albumin Concentration ◽  
Steady State Level ◽  
Morphological Alterations ◽  
Central Lobe ◽  
Nuclear Alterations

Functional and morphological alterations were generated by p.o. (per os) administration of a single oral dose of carbon tetrachloride (CCl4; 0.125 mL/kg b.w., equivalent to 293 mg/kg) to adult male Wistar rats. CCl4 significantly increased (p < 0.05) the serum activities of alanine aminotransferase (ALT; 7478 ± 1044%) and aspartate aminotransferase (AST; 6964 ± 833%), compared to control rats; CCl4 also significantly decreased serum concentration of albumin (23 ± 5.5%) and increased the concentration of malondialhdeyde (MDA) in liver (300 ± 33%). Furthermore, CCl 4 down-regulated the mRNA steady-state level of tumor necrosis factor a(TNF-a). CCl4 produced necrosis in the central lobe area, extended to the periphery, nuclear alterations (pycnosis, karyolysis and karyorrhexis), and cytoplasmic acidophilia. The pretreatment with 4 mg/kg (p.o.) of Ginkgo biloba extract (GbE), for 5 days, prevented most of the damage caused by CCl4: significantly decreased the serum activities of ALT and AST (54 and 65%, respectively), compared to CCl4-treated rats; GbE partially prevented the increase of liver MDA (55 ± 14%) and the decrease of albumin concentration to 12 ± 0.2%. This pretreatment prevented the down-regulation of TNF-a and up-regulated the interleukine 6 (IL-6) mRNA steady-state level. Moreover, the GbE reduced the amount of necrotic areas in the central lobe area, compared to CCl4-treated rats.

scholarly journals Microsurgical management of a high-grade brain arteriovenous malformation in the central lobe after unsuccessful radiosurgery

2017 ◽  
Vol 43 (videosuppl1) ◽  
pp. V3
Author(s):  
Jean G. de Oliveira ◽  
Carlos R. Massella ◽  
Carlos Vanderlei M. de Holanda ◽  
Miguel Giudicissi-Filho ◽  
Luis A. B. Borba
Keyword(s):  
Great Majority ◽  
Neurological Deficits ◽  
High Grade ◽  
Brain Arteriovenous Malformation ◽  
Previous Surgery ◽  
Good Clinical Outcome ◽  
Sensorimotor Deficits ◽  
Eloquent Areas ◽  
Central Lobe ◽  
Microsurgical Resection

The recommendation for the great majority of high-grade brain arteriovenous malformations (bAVMs) is observation, except for those patients with recurrent hemorrhages, progressive neurological deficits, steal-related symptoms, or AVM-related aneurysms, for whom intervention should be considered. These are general recommendations, and the decision should be made on an individual basis. Surgical resection of an AVM in the central lobe may cause postoperative sensorimotor deficits since this anatomical region includes the pre- and postcentral gyri on the lateral surface and the paracentral lobule on the medial surface.The authors present a patient with a ruptured high-grade bAVM in the central lobe who underwent previous surgery for hematoma evacuation and previous radiosurgery, and whose indication for reoperation was proposed based on progressive hemiparesis. Microsurgical resection was possible after a wide frontoparietal craniotomy, which made all the nidus borders accessible. This case illustrates the anatomy and surgical technique for large nidus AVMs in eloquent areas, showing that complete microsurgical resection is possible with good clinical outcome.The video can be found here: https://youtu.be/Cpd1PK6BLIM.

10.5 W central lobe output power obtained with an efficient 1030 nm DBR tapered diode laser

2017 ◽  
Author(s):  
Andre Muller ◽  
Christof Zink ◽  
Arnim Ginolas ◽  
Jorg Fricke ◽  
Frank Bugge ◽  
...  
Keyword(s):  
Diode Laser ◽  
Output Power ◽  
Central Lobe ◽  
Tapered Diode Laser

The Generation and Propagation of Ship Internal Waves in a Generally Stratified Ocean at High Densimetric Froude Numbers, Including Nonlinear Effects

2000 ◽  
Vol 44 (03) ◽  
pp. 197-227
Author(s):  
Marshall P. Tulin ◽  
Yitao Yao ◽  
Pei Wang
Keyword(s):  
Internal Wave ◽  
Internal Waves ◽  
Near Field ◽  
Nonlinear Effects ◽  
Wave Pattern ◽  
Small Scale ◽  
Far Field ◽  
Asymptotic Equation ◽  
Densimetric Froude Number ◽  
Central Lobe

A nonlinear theory for internal wave generation and propagation is derived here for slender ships traveling at high densimetric Froude number (Fh &gt;&gt; 1) in water of small density variation. It is based on an asymptotic equation for the evolution of the internal wave vorticity generated under the ship by a known inviscid ship flow and then self-propagating in the wake. In its numerical implementation, arbitrary pycnoclines and slender ship hulls may be used, and boundary conditions on the ship hull are satisfied; the free surface is treated here as rigid, although this may be relaxed. The theory has been implemented by a suitable numerical method and numerous simulations have been carried out. The results have been compared with earlier OEL experiments. In the near field, emphasis is given to a triple-lobe pattern in the pycnocline, an upwelling along the centerline of motion with a trough on either side, forming close behind the ship. Two distinct types of triple lobes are identified:dominant central lobe and very weak troughs, and;weak central lobe and dominant troughs. The former (a) is shown to result in linear propagation into the far field. The latter (b) results in far-field patterns preceded by a deep trough whose propagation is nonlinear. The comparisons of both simulated trends and actual amplitudes with measurements are good, surprisingly so considering the small scale of the experiment and the asymptotic nature of the theory. The effect of the turbulent wake on the internal waves in the experiments is restricted to a very narrow region behind the ship; the bulk of the wave pattern including the leading waves seem unaffected. Simulations show that under certain conditions of stratification, triple-lobe patterns with abnormally large troughs are generated and lead to strong nonlinear effects; these deep troughs propagate sidewards to large distances aft (over 40 ship lengths) with slow decay, and result in much larger surface currents and strain rates than in the normal case. Correspondingly, fast waves of depression, which decay slowly, were discovered through the simulation of two-dimensional initial value problems, where the initial area of depression was significantly less than required of a true soliton; these "quasi-solitons" are briefly studied here.

Spatial distribution of groundwater-surface water connectivity in the Kosimegafan, north India

2021 ◽  
Author(s):  
Zafar Beg ◽  
Suneel Kumar Joshi ◽  
Kumar Gaurav ◽  
Sudhir Kumar
Keyword(s):  
Surface Water ◽  
Water Level ◽  
Stream Water ◽  
Ground Level ◽  
Isotopic Analysis ◽  
North India ◽  
Spatial And Temporal Variation ◽  
Recharge Rate ◽  
Groundwater Levels ◽  
Central Lobe

&lt;p&gt;We conducted a systematically integrated surface water and groundwater interaction study in the Kosimegafan in north India using the stable isotopes (&amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H) of water and depth to water level data. In a field campaign in December 2019, we have collected a water sample from 65 different locations for isotopic analysis. This includes 21 samples from the groundwater and 44 from different surface water bodies (Kosi River-02, streams-09, waterlogged patches-29, and canal-04).&lt;/p&gt;&lt;p&gt;The &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and D-excess values of groundwater and waterlogged samples show marked spatial variation across the study area. Using a two-component mixing model, we estimate the fraction contribution of streams and rainwater in the groundwater and waterlogged patches. This shows a marked spatial and depth-related variability in stream water contribution to the groundwater recharge and varies from about 83% (maximum) at 6 m below ground level (bgl) to 45% (minimum) at 9 m bgl. We also analysed the spatial and temporal variation in groundwater levels from 1996 to 2017. During this period, the water level shows a significant variation from 1.1 to 7.8 m bgl. Further, using the water table fluctuation approach, we estimate the recharge rate. We found a higher recharge rate (22 mm/year) in the central part of the western lobe and northern part of the central lobe, and minimum (1 mm/year)in both the northern part of the western and southern part of the central lobe of the Kosi fan. This study provides new insight into the recharge processes in the study area.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document