556 research outputs found
Performance Analysis of Reactive Routing Protocols AODV, DYMO, DSR, LAR in MANETs
MANETs are one the cutting-edgeevolving wireless technologies. The routing in mobile ad hoc networksplays a vital role and has been researchedwide-range in last decade. The routing protocols are classified as proactive,reactive and hybrid. Reactive routing protocols are considered for its advantages compared to others. In this paper, reactive routing protocols, Ad Hoc On-demand Distance Vector (AODV), Dynamic MANET On-demand (DYMO) protocol, Dynamic Source Routing protocol (DSR), Location Aided Routing protocol have been selected to analyze the performance and compare the routing protocols by varying Network size and Mobility speed to various levels. The performance metrics analyzed were Average Throughput, Average End-to-End Delay, Average Jitter, Energy Consumed in Transmit Mode, Energy Consumed in Receive Mode. The simulations were carried on Exata 5.4 simulator. The analysis of the routing protocols for the configuration setting is presented at the conclusion
Seat of the Joshi Effect in A.C. Silent Discharges
Some experiments on the positive and negative Joshi effects in 'sleeve' discharge tubes containing iodine vapour and hydrogen gas have been performed to Study the effect of illuminating the different parts of each discharge tube successively by a narrow
beam of strong light. The results of these experiments are given in the piper with an account of the experimental arrangements. The results have shown that the Joshi effect (positive and negative) is associated predominantly with the regions of the electrodes.
The role of the discharge column of the lube in the production of the Joshi effect, if any, is, however, regarded as uncertain.
The effect of stray light affecting the electrodes after being scattered from the illuminated part of the discharge tube is considered in discussing the experimental results
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Microscopic mechanism for fluctuating pair density wave
In weakly coupled BCS superconductors, only electrons within a tiny energy
window around the Fermi energy, , form Cooper pairs. This may not be the
case in strong coupling superconductors such as cuprates, FeSe, SrTiO or
cold atom condensates where the pairing scale, , becomes comparable or
even larger than . In cuprates, for example, a plausible candidate for the
pseudogap state at low doping is a fluctuating pair density wave, but no
microscopic model has yet been found which supports such a state. In this work,
we write an analytically solvable model to examine pairing phases in the
strongly coupled regime and in the presence of anisotropic interactions.
Already for moderate coupling we find an unusual finite temperature phase,
below an instability temperature , where local pair correlations have
non-zero center-of-mass momentum but lack long-range order. At low temperature,
this fluctuating pair density wave can condense either to a uniform -wave
superconductor or the widely postulated pair-density wave phase depending on
the interaction strength. Our minimal model offers a unified microscopic
framework to understand the emergence of both fluctuating and long range pair
density waves in realistic systems.Comment: 13 pages, 6 figures including Supplemental Materia
Prevalence of deep and ovarian endometriosis in women attending a general gynecology clinic: prospective cohort study
Objectives: To assess using transvaginal ultrasound the prevalence of deep and ovarian endometriosis in premenopausal women attending a general gynecology clinic. We also investigated whether the presence of endometriosis was associated with various demographic factors and other pelvic abnormalities. Methods: This was a prospective observational cohort study carried out between February 2019 and October 2020. Consecutive premenopausal women who attended our general gynecology clinic underwent pelvic ultrasound examination, performed by a single experienced operator. Pregnant women and those with a history of hysterectomy or oophorectomy were excluded. The primary outcome was the prevalence of deep and/or ovarian endometriosis. Secondary outcomes were the anatomical distribution of endometriotic lesions and the association of endometriosis with demographic characteristics and various pelvic abnormalities, which were analyzed using logistic regression and multivariable analysis. Results: A total of 1026 women were included in the final study sample, of whom 194 (18.9% (95% CI, 16.6–21.4%)) had sonographic evidence of deep and/or ovarian endometriosis. Of the 194 women diagnosed with endometriosis, 106 (54.6% (95% CI, 47.4–61.8%)) were diagnosed with endometriotic nodules only, 26 (13.4% (95% CI, 9.0–19.0%)) with ovarian endometriomas only, and 62 (32.0% (95% CI, 25.5–39.0%)) women had evidence of both. There was a total of 348 endometriotic nodules in 168 women, located most frequently in the retrocervical area (166/348; 47.7% (95% CI, 42.4–53.1%)), uterosacral ligaments (96/348; 27.6% (95% CI, 23.0–32.6%)) and bowel (40/348; 11.5% (95% CI, 8.3–15.3%)). Multivariable analysis found significant positive associations between endometriosis and both adenomyosis (odds ratio (OR), 1.72 (95% CI, 1.10–2.69); P = 0.02) and pelvic adhesions (OR, 25.7 (95% CI, 16.7–39.3); P < 0.001), whilst higher parity (OR, 0.44 (95% CI, 0.24–0.81); P = 0.03) and history of Cesarean section (OR, 0.18 (95% CI, 0.06–0.52); P = 0.002) were associated with a lower occurrence of endometriosis. A total of 75/1026 women (7.3% (95% CI, 5.8–9.1%)) underwent laparoscopy within 6 months of pelvic ultrasound examination. There was very good agreement between ultrasound and surgical findings, with a kappa value of 0.84 (95% CI, 0.69–0.99). Conclusions: Deep and/or ovarian endometriosis was present in nearly one in five women attending a general gynecology clinic. There were significant positive associations with adenomyosis and pelvic adhesions and negative associations with higher parity and previous Cesarean section
Multi component one pot synthesis and characterization of derivatives of 2-amino-7,7- dimethyl-5-oxo-4-phenyl-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile and study of anti-microbial activity
An efficient and convenient procedure has been described for one-pot multi-component synthesisof tetrahydrobenzo[b]pyrans known as 2-amino-7,7-dimethyl-5-oxo-4-phenyl-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile which can be obtained from the reaction of substituted aromatic aldehydes, dimedone, malonitrile, in the presence of base such as potassium tertiary butoxide and THF in methanol as solvent at RT condition. All the compounds were examined by advanced spectroscopic data (1H NMR, 13C NMR and LCMS) and the structural determination was evaluated by elemental analysis. In addition to this, all the newly synthesized compounds were examined for their antibacterial activities and antifungal activity by disc diffusion method against the organism of Aspergillus niger and Candida ablicans L. KEY WORDS: Aromatic aldehydes, Dimedone, Malonitrile, Potasium tertiary butoxide, 2-Amino-7,7-dimethyl-5-oxo-4-phenyl-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile, Anti-microbial activity Bull. Chem. Soc. Ethiop. 2018, 32(1), 133-138DOI: https://dx.doi.org/10.4314/bcse.v32i1.1
Anomalous attenuation of extraordinary waves in the ionosphere heating experiments
Multiple scattering of radio waves by artificial random irregularities
HF-induced in the ionosphere F region may cause significant attenuation of both
ordinary and extraordinary waves together with common anomalous absorption of
ordinary waves due to their non-linear conversion into plasma waves. To
demonstrate existence and strength of this effect, direct measurements of
attenuation of both powerful pump wave and weak probing waves of extraordinary
polarization have been carried out during an experimental campaign on September
6, 7 and 9, 1999 at the Sura heating facility. The attenuation magnitude of
extraordinary waves reaches of 1-10 dB over a background attenuation caused by
natural irregularities. It is interpreted in the paper on the base of the
theory of multiple scattering from the artificial random irregularities with
characteristic scale lengths of 0.1-1 km. Simple procedure for determining of
irregularity spectrum parameters from the measured attenuation of extraordinary
waves has been implemented and some conclusions about the artificial
irregularity formation have been obtained.Comment: 17 pages, 9 figure
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