261 research outputs found

    Electromagnetic modes of Maxwell fisheye lens

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    We provide an analysis of the radial structure of TE and TM modes of the Maxwell fisheye lens, by means of Maxwell equations as applied to the fisheye case. Choosing a lens of size R = 1 cm, we plot some of the modes in the infrared range.Comment: 2+6 pages in Latex, 3 figures to be found in the published referenc

    Impacts Of The Aggregate Economic And Financial Conditions On Output In An Emerging Economy

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    This study formulates the theoretical model based on the money market equilibrium, the goods market equilibrium, and an augmented aggregate supply function. The sample ranges from 1996.Q1 to 2009.Q3 and has 55 observations. Applying the generalized autoregressive conditional heteroskedasticity (GARCH) model, this paper finds that Brazil’s real GDP is positively impacted by real M2 money supply, the real stock price, world output and the expected inflation rate and is negatively influenced by the government deficit as a percent of GDP, the real BRL/USD exchange rate and the U.S. Treasury bill rate. The first and third quarters exhibit seasonal effects. Therefore, expansionary monetary policy is more effective than deficit-financed expansionary fiscal policy, and pursuing real appreciation, promoting a robust stock market, and maintaining a strong world economy will benefit the Brazilian economy

    IONORT: a Windows software tool to calculate the HF ray tracing in the ionosphere

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    This paper describes an applicative software tool, named IONORT (IONOspheric Ray Tracing), for calculating a three-dimensional ray tracing of high frequency waves in the ionospheric medium. This tool runs under Windows operating systems and its friendly graphical user interface facilitates both the numerical data input/output and the two/three-dimensional visualization of the ray path. In order to calculate the coordinates of the ray and the three components of the wave vector along the path as dependent variables, the core of the program solves a system of six first order differential equations, the group path being the independent variable of integration. IONORT uses a three-dimensional electron density specification of the ionosphere, as well as by geomagnetic field and neutral particles-electrons collision frequency models having validity in the area of interest.Comment: 25 pages, 7 figures, 2 table

    Broadside radar echoes from ionized trails

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77210/1/AIAA-2347-553.pd

    Relativity principles in 1+1 dimensions and differential aging reversal

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    We study the behavior of clocks in 1+1 spacetime assuming the relativity principle, the principle of constancy of the speed of light and the clock hypothesis. These requirements are satisfied by a class of Finslerian theories parametrized by a real coefficient ÎČ\beta, special relativity being recovered for ÎČ=0\beta=0. The effect of differential aging is studied for the different values of ÎČ\beta. Below the critical values ∣ÎČ∣=1/c|\beta| =1/c the differential aging has the usual direction - after a round trip the accelerated observer returns younger than the twin at rest in the inertial frame - while above the critical values the differential aging changes sign. The non-relativistic case is treated by introducing a formal analogy with thermodynamics.Comment: 12 pages, no figures. Previous title "Parity violating terms in clocks' behavior and differential aging reversal". v2: shortened introduction, some sections removed, pointed out the relation with Finsler metrics. Submitted to Found. Phys. Let

    Quiet daytime Arctic ionospheric D region

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    Phase and amplitude measurements of VLF radio waves propagating sub‐ionospherically on long paths across the Arctic are used to determine the high latitude, daytime D region height and sharpness of the bottom edge of the Earth's ionosphere. The principal path used is from the 23.4 kHz transmitter, DHO, in north Germany, northwards across the Arctic passing ~2° from the North Pole, and then southwards to Nome, Alaska, thus avoiding most land and all thick ice. Significant observational support is obtained from the also nearly all‐sea path from JXN in Norway (~67° N, 16.4 kHz) across the North Pole to Nome. By suitably comparing measurements with modeling using the US Navy code LWPC, the daytime D region (Wait) height and sharpness parameters in the Arctic are found to be H' = 73.7 ± 0.7 km and ß = 0.32 ±0.02 km‐1 in the summer of 2013 ‐ i.e., at (weak) solar maximum. It is also found that, unlike at lower latitudes, VLF phase and amplitude recordings on (~1000 km) paths at high subarctic latitudes show very little change with solar zenith angle in both phase and amplitude during daytime for solar zenith angles ~300 keV for electrons) with a contribution from galactic cosmic rays, rather than by solar Lyman‐α which dominates at low and middle latitudes

    Long-term impact of the COVID-19 pandemic on the quality of life of people with dementia and their family carers

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    \ua9 The Author(s) 2024. Published by Oxford University Press on behalf of the British Geriatrics Society. INTRODUCTION: Few studies have longitudinally mapped quality of life (QoL) trajectories of newly diagnosed people with dementia and their carers, particularly during coronavirus disease-2019 (COVID-19). METHODS: In a UK cohort study, 261 newly diagnosed people with dementia and 206 family carers were assessed prior to the pandemic (July 2019-March 2020), followed up after the first lockdown (July-October 2020) and then again a year and 2 years later. Latent growth curve modelling examined the level and change of QoL over the four time-points using dementia-specific QoL measures (DEMQOL and C-DEMQOL). RESULTS: Despite variations in individual change scores, our results suggest that generally people with dementia maintained their QoL during the pandemic and experienced some increase towards the end of the period. This contrasted with carers who reported a general deterioration in their QoL over the same period. \u27Confidence in future\u27 and \u27Feeling supported\u27 were the only carer QoL subscales to show some recovery post-pandemic. DISCUSSION: It is positive that even during a period of global disruption, decline in QoL is not inevitable following the onset of dementia. However, it is of concern that carer QoL declined during this same period even after COVID-19 restrictions had been lifted. Carers play an invaluable role in the lives of people with dementia and wider society, and our findings suggest that, post-pandemic, they may require greater support to maintain their QoL

    Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics

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    The atmospheric greenhouse effect, an idea that many authors trace back to the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896), and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles are clarified. By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.Comment: 115 pages, 32 figures, 13 tables (some typos corrected
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