scholarly journals The transmission of electric waves around the Earth's surface

1925 ◽  
Vol 108 (745) ◽  
pp. 52-76
Keyword(s):  
Steady State ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Conducting Layer ◽  
Ordinary Sense ◽  
Magnetic Forces ◽  
Electrical Oscillation ◽  
Set Up ◽  
Time Required ◽  
Short Time

The transmission of wireless signals to very great distances, and certain other phenomena associated with wireless telegraphy, have been ascribed by several writers to the presence of a conducting layer in the upper atmosphere. Such a layer, if it were conducting in the ordinary sense, would act as a screen in respect of electrical effects which had their origin external to the layer, and further, as has been shown, electrical disturbances set up in the space between the conducting layer and the earth’s surface would subside so slowly that the time required to establish an approximately steady state would be very great. It appears natural, therefore, to assume that, if there is reflexion from the upper atmosphere, there must also be radiation through it to allow a steady state to be attained in a comparatively short time, and the simplest hypothesis consistent with this is that the upper atmosphere differs from the lower atmosphere in respect of the constants involved in the propagation of electrical effects through the atmosphere, viz., the specific inductive capacity and the magnetic permeability. It is proposed to investigate on this hypothesis the condition that a steady state of electrical oscillation can be established in the lower atmosphere in a comparatively short time, and the distribution of electric and magnetic forces on the earth’s surface due to a simple oscillator near to the surface when this condition is satisfied.

scholarly journals The European TeleCheck-AF project on remote app-based management of atrial fibrillation during the COVID-19 pandemic: centre and patient experiences

EP Europace ◽  
2021 ◽  
Author(s):  
Monika Gawałko ◽  
David Duncker ◽  
Martin Manninger ◽  
Rachel M J van der Velden ◽  
Astrid N L Hermans ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Care Delivery ◽  
Patient Characteristics ◽  
Patient Experiences ◽  
Af Ablation ◽  
District Hospitals ◽  
Inclusion Rate ◽  
Set Up ◽  
Time Required ◽  
Short Time

Abstract Aims TeleCheck-AF is a multicentre international project initiated to maintain care delivery for patients with atrial fibrillation (AF) during COVID-19 through teleconsultations supported by an on-demand photoplethysmography-based heart rate and rhythm monitoring app (FibriCheck®). We describe the characteristics, inclusion rates, and experiences from participating centres according the TeleCheck-AF infrastructure as well as characteristics and experiences from recruited patients. Methods and results Three surveys exploring centre characteristics (n = 25), centre experiences (n = 23), and patient experiences (n = 826) were completed. Self-reported patient characteristics were obtained from the app. Most centres were academic (64%) and specialized public cardiology/district hospitals (36%). Majority of the centres had AF outpatient clinics (64%) and only 36% had AF ablation clinics. The time required to start patient inclusion and total number of included patients in the project was comparable for centres experienced (56%) or inexperienced in mHealth use. Within 28 weeks, 1930 AF patients were recruited, mainly for remote AF control (31% of patients) and AF ablation follow-up (42%). Average inclusion rate was highest during the lockdown restrictions and reached a steady state at a lower level after easing the restrictions (188 vs. 52 weekly recruited patients). Majority (>80%) of the centres reported no problems during the implementation of the TeleCheck-AF approach. Recruited patients [median age 64 (55–71), 62% male] agreed that the FibriCheck® app was easy to use (94%). Conclusion Despite different health care settings and mobile health experiences, the TeleCheck-AF approach could be set up within an extremely short time and easily used in different European centres during COVID-19.

scholarly journals The transmission of electric waves around the earth's surface

1921 ◽  
Vol 98 (694) ◽  
pp. 409-411
Keyword(s):  
Steady State ◽  
Total Energy ◽  
Magnetic Force ◽  
Legendre Function ◽  
Mathematical Problem ◽  
Time Factor ◽  
Conducting Layer ◽  
Spherical Surfaces ◽  
Set Up ◽  
Electric Waves

In the ‘ Proceedings,’ Prof. G. N. Watson discusses the effect of a perfectly conducting layer in the atmosphere at a uniform height above the earth’s surface on the transmission of electric waves round the earth. The mathe­matical treatment adopted by him assumes that the time factore e - αCt can be removed from all the equations, and that the analytical results thus obtained represent the effect of a simple oscillator placed near the earth’s surface. The assumption that the time factor can be removed is equivalent to assuming that a steady state of oscillations exists in the space between the two spheres, such that at the end of a period the amplitudes of the electric and magnetic forces are identical at each point with the values they had at the beginning of the period. Now, when the surfaces of both spheres are perfectly conducting, no energy is transmitted across either surface, and therefore, if there is a steady state of oscillations in the space, the total energy in the space must be constant. When there is an oscillator in the space emitting electric waves, there is a finite amount of energy radiated from the oscillator in each period, and therefore the total energy in the space does not remain constant; it follows that in such a case there is no steady state of oscillations and the mathematical problem involved cannot be treated by assuming that there is a time factor which can be removed. The effect of any electric disturbance set up in the space between the two perfectly conducting spherical surfaces can be expressed in the usual way in terms of the natural periods of the space. If a and b are the radii of the two concentric spherical surfaces, the equation which determines the periods corresponding to the Legendre function of order n , when the disturbance is such that the lines of magnetic force are circles with the axis of the harmonics as a common axis.

scholarly journals The condition that the ratio of the intensities of the transmitted and reflected electric waves at the interface between two media is independent of their plane of polarisation

1925 ◽  
Vol 108 (747) ◽  
pp. 386-392
Keyword(s):  
Steady State ◽  
Magnetic Permeability ◽  
Outer Boundary ◽  
Electric Force ◽  
Present Communication ◽  
Dielectric Media ◽  
Set Up ◽  
Short Time ◽  
Incident Waves ◽  
Electric Waves

It has been shown that the condition that a steady state of electrical oscillations can be set up in a comparatively short time in a space, whose outer boundary separates two dielectric media with different electric constants, is that the ratio of the specific inductive capacities of the two media is approximately equal to the ratio of the magnetic permeabilities. This suggests that, when the ratios are equal, the ratios of the incident, transmitted, and reflected disturbances are independent of the direction of the plane of polarisation of the incident disturbance, and this can be readily verified. The object of the present communication is to prove that the condition is necessary, that is, the condition that the ratios of the intensities of the incident, transmitted, and reflected electric waves at the interface between two media is independent of the direction of the plane of polarisation of the incident waves is that the ratio of the specific inductive capacities of the two media is equal to the ratio of the magnetic permeabilities of the two media. Taking the plane of separation of the two media to be the plane z = 0, let K, μ be the specific inductive capacity and the magnetic permeability respectively of the medium for which z > 0, and let K', μ' be the specific inductive capacity and the magnetic permeability of the medium for which z ˂ 0, and let the electric force in the incident waves be given by (A, B, C) e tk ( lx+my+nz +V t ) , where A l + B m + C n = 0, KμV 2 = 1;

scholarly journals What do <sup>14</sup>CO measurements tell us about OH?

2007 ◽  
Vol 7 (4) ◽  
pp. 10405-10438 ◽  
Author(s):  
M. C. Krol ◽  
J. Fokke Meirink ◽  
P. Bergamaschi ◽  
J. E. Mak ◽  
D. Lowe ◽  
...  
Keyword(s):  
Source Region ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Atmospheric Measurements ◽  
Model Calculations ◽  
Mixing Ratios ◽  
Short Time Span ◽  
The Tropics ◽  
Short Time ◽  
Model Measurement

Abstract. The possible use of 14CO measurements to constrain hydroxyl radical (OH) concentrations in the atmosphere is investigated.14CO is mainly produced in the upper atmosphere from cosmic radiation. During transport to measurement locations at the Earth's surface 14CO is oxidized by OH. In this paper, the sensitivity of 14CO mixing ratio measurements to the 3-D OH distribution is assessed with the TM5 model. Simulated 14CO mixing ratios compare reasonably well with atmospheric measurements taken at five locations worldwide. As a next step, the sensitivity of 14CO measurements to OH is calculated with the adjoint TM5 model. For our sensitivity calculations the adjoint methodology outlined in the paper offers computational advantages compared to forward model calculations. The results indicate that 14CO measurements, especially those taken in the tropics, are sensitive to OH in a spatially confined region. Moreover, the OH sensitivity at a certain location varies strongly over time due to meteorological variability. On average, 14CO measurements are about 5 times more sensitive to OH at high latitudes than to OH in the tropics. Moreover, the measurements are sensitive to OH in the main 14CO source region in the upper atmosphere. It will therefore be difficult to assign model-measurement discrepancies to either the 14CO source uncertainty or to the OH sink. Nevertheless, the large distance between the 14CO source region and the measurement locations should allow the retrieval of information on OH. Specifically, the sensitivity to OH in the lower atmosphere during a relatively short time span may offer the possibility to constrain local OH. These efforts will strongly depend on the number of measurements available and on our ability to accurately model the 14CO transport.

Effect of Vial shaking on Loading Time of Epirubicin into Drug-Eluting Bead

2015 ◽  
Vol 5 (3) ◽  
Author(s):  
Kenji Ikeda ◽  
Yusuke Kawamura ◽  
Masahiro Kobayashi ◽  
Taito Fukushima ◽  
Yushi Sorin ◽  
...  
Keyword(s):  
Antitumor Agent ◽  
Loading Rates ◽  
Vortex Mixer ◽  
Long Time ◽  
Group A ◽  
Drug Eluting ◽  
Large Hepatocellular Carcinoma ◽  
Group B ◽  
Time Required ◽  
Short Time

Background: Although DC Bead has been useful in treatment of multiple and large hepatocellular carcinoma, loading time of doxorubicin into the DC Bead takes a long time of 30-120 minutes. Epirubicin is also used as an antitumor agent together with DC Bead, but its loading efficiency was not sufficiently elucidated. Methods: To shorten loading time of epirubicin into DC Bead (100-300µm, 300-500µm, 500-700µm), we examined the following three methods after mixing the drug: (a) let stand in room temperature, (b) agitated for 30 seconds with Vortex mixer, and (c) sonicated for 30 seconds with ultrasonic cleaner. After loading of epirubicin by each method, supernatant concentration for epirubicin was assayed at 5, 10, 30, 60, and 120 minutes. Results: Epirubicin loading rates for small bead (100-300µm) at 5 minutes were 82.9 % in group a, 93.8% in group b, and 79.9 % in group c. Similarly, medium bead (300-500µm), 40.1% in group a, 65.7% in group b and 45.5% in group c, respectively. In large-sized bead (500-700µm), loaded rates of epirubicin were 38.8% in group a, 59.0% in group b and 48.0% in group c. Agitation of mixture of epirubicin and DC Bead with Vortex mixer significantly shortened the loading time, but sonication did not affect the time required. Microscopic examination did not lead to any morphological change of microspheres in all the methods. Conclusions: Short time of agitation with Vortex mixer reduced the necessary time for loading of epirubicin in every standard of DC Bead.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Marital Disharmony among Working Couples in Metropolitan Life: an In-depth Study in Kolkata City

2019 ◽  
Vol 8 (8) ◽  
pp. 72-85
Author(s):  
Nilanjana Ghoshal ◽  
Mst Tania Parveen ◽  
Dr Asraful Alam
Keyword(s):  
Functional Method ◽  
Modern Times ◽  
Metropolitan Cities ◽  
Urban India ◽  
Depth Study ◽  
Working Couples ◽  
Set Up ◽  
Time Required ◽  
The City ◽  
Opposite Gender

In India, traditionally and from time immemorial, marriage has always been a sacred bond for people of this country. The aim of this study is to explain a socially sanctioned sex relationship involving people of two opposite gender whose relationship is expected to endure beyond time required for gestation. The functional method of the study has been set up on the field-based observation to find out the reasons behind rising of marital disharmony among working couples. But the problem is initially in modern times the concept of marriage is gradually taking a different turn between couples. Hence the focus of this paper is to study the various factors giving rise to marital disharmonies among working couples in urban India and how these discords can be solved so that couples can lead a happy harmonious married life ahead. Survey has been done in the city of Kolkata taking people from various walks of life. As Kolkata is one of the major Metropolitan cities of India it was easier to find people belonging to different professions. The result of this study is every marriage brings challenges in life. Maximum working couples are losing attachment with each other as they have lack of time for each other. Bringing work at home, sharing of parenthood, indifference towards each other, lack of adjustments are the causes for which level of disharmony is increasing.

scholarly journals Environmental Engineering Techniques to Restore Degraded Posidonia oceanica Meadows

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 661
Author(s):  
Luigi Piazzi ◽  
Stefano Acunto ◽  
Francesca Frau ◽  
Fabrizio Atzori ◽  
Maria Francesca Cinti ◽  
...  
Keyword(s):  
Large Scale ◽  
Natural Habitat ◽  
Cost Benefit ◽  
Cost Effective ◽  
Posidonia Oceanica ◽  
Environmental Engineering ◽  
Bottom Surface ◽  
Sessile Invertebrates ◽  
Set Up ◽  
Short Time

Seagrass planting techniques have shown to be an effective tool for restoring degraded meadows and ecosystem function. In the Mediterranean Sea, most restoration efforts have been addressed to the endemic seagrass Posidonia oceanica, but cost-benefit analyses have shown unpromising results. This study aimed at evaluating the effectiveness of environmental engineering techniques generally employed in terrestrial systems to restore the P. oceanica meadows: two different restoration efforts were considered, either exploring non-degradable mats or, for the first time, degradable mats. Both of them provided encouraging results, as the loss of transplanting plots was null or very low and the survival of cuttings stabilized to about 50%. Data collected are to be considered positive as the survived cuttings are enough to allow the future spread of the patches. The utilized techniques provided a cost-effective restoration tool likely affordable for large-scale projects, as the methods allowed to set up a wide bottom surface to restore in a relatively short time without any particular expensive device. Moreover, the mats, comparing with other anchoring methods, enhanced the colonization of other organisms such as macroalgae and sessile invertebrates, contributing to generate a natural habitat.

scholarly journals Simple low dose radiography allows precise lung volume assessment in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amara Khan ◽  
Andrea Markus ◽  
Thomas Rittmann ◽  
Jonas Albers ◽  
Frauke Alves ◽  
...  
Keyword(s):  
Lung Function ◽  
Whole Body ◽  
Acquisition Time ◽  
Micro Ct ◽  
Lung Volumes ◽  
X Ray ◽  
Promising Tool ◽  
Volume Assessment ◽  
Set Up ◽  
Time Required

AbstractX-ray based lung function (XLF) as a planar method uses dramatically less X-ray dose than computed tomography (CT) but so far lacked the ability to relate its parameters to pulmonary air volume. The purpose of this study was to calibrate the functional constituents of XLF that are biomedically decipherable and directly comparable to that of micro-CT and whole-body plethysmography (WBP). Here, we developed a unique set-up for simultaneous assessment of lung function and volume using XLF, micro-CT and WBP on healthy mice. Our results reveal a strong correlation of lung volumes obtained from radiographic XLF and micro-CT and demonstrate that XLF is superior to WBP in sensitivity and precision to assess lung volumes. Importantly, XLF measurement uses only a fraction of the radiation dose and acquisition time required for CT. Therefore, the redefined XLF approach is a promising tool for preclinical longitudinal studies with a substantial potential of clinical translation.

The Reduction of Bias Error in Transfer Function Estimates Using FFT-Based Analyzers

1984 ◽  
Vol 106 (1) ◽  
pp. 29-35 ◽  
Author(s):  
P. Cawley
Keyword(s):  
Transfer Function ◽  
Random Excitation ◽  
Analogue Computer ◽  
Bias Error ◽  
Testing Time ◽  
Theoretical Predictions ◽  
Set Up ◽  
Modal Mass ◽  
Time Required ◽  
Good Agreement

The susceptibility to bias error of two methods for computing transfer (frequency response) functions from spectra produced by FFT-based analyzers using random excitation has been investigated. Results from tests with an FFT analyzer on a single degree-of-freedom system set up on an analogue computer show good agreement with the theoretical predictions. It has been shown that, around resonance, the bias error in the transfer function estimate H2 (Syy/Sxy*) is considerably less than that in the more commonly used estimate, H1 (Sxy/Sxx). The record length, and hence the testing time, required for a given accuracy is reduced by over 50 percent if the H2 calculation procedure is used. The analysis has also shown that if shaker excitation is used on lightly damped structures with low modal mass, it is important to minimize the mass of the force gage and the moving element of the shaker.

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