1,097 research outputs found
Cornering the revamped BMV model with neutrino oscillation data
Using the latest global determination of neutrino oscillation parameters
from~\cite{deSalas:2017kay} we examine the status of the simplest revamped
version of the BMV (Babu-Ma-Valle) model, proposed in~\cite{Morisi:2013qna}.
The model predicts a striking correlation between the "poorly determined"
atmospheric angle and CP phase , leading to either
maximal CP violation or none, depending on the preferred octants.
We determine the allowed BMV parameter regions and compare with the general
three-neutrino oscillation scenario. We show that in the BMV model the higher
octant is possible only at C.L., a stronger rejection than found in the
general case. By performing quantitative simulations of forthcoming DUNE and
T2HK experiments, using only the four "well-measured" oscillation parameters
and the indication for normal mass ordering, we also map out the potential of
these experiments to corner the model. The resulting global sensitivities are
given in a robust form, that holds irrespective of the true values of the
oscillation parameters.Comment: 5 pages, 2 figure
New Perspective on the Optical Theorem of Classical Electrodynamics
A general proof of the optical theorem (also known as the optical
cross-section theorem) is presented that reveals the intimate connection
between the forward scattering amplitude and the absorption-plus-scattering of
the incident wave within the scatterer. The oscillating electric charges and
currents as well as the electric and magnetic dipoles of the scatterer, driven
by an incident plane-wave, extract energy from the incident beam at a certain
rate. The same oscillators radiate electro-magnetic energy into the far field,
thus giving rise to well-defined scattering amplitudes along various
directions. The essence of the proof presented here is that the extinction
cross-section of an object can be related to its forward scattering amplitude
using the induced oscillations within the object but without an actual
knowledge of the mathematical form assumed by these oscillations.Comment: 7 pages, 1 figure, 12 reference
Deducing radiation pressure on a submerged mirror from the Doppler shift
Radiation pressure on a flat mirror submerged in a transparent liquid,
depends not only on the refractive index n of the liquid, but also on the phase
angle psi_0 of the Fresnel reflection coefficient of the mirror, which could be
anywhere between 0^{\circ} and 180^{\circ}. Depending on the value of psi_0,
the momentum per incident photon picked up by the mirror covers the range
between the Abraham and Minkowski values, i.e., the interval
(2\hbarw_0/nc,2n\hbarw_0/c). Here \hbar is the reduced Planck constant, w_0 is
the frequency of the incident photon, and c is the speed of light in vacuum. We
argue that a simple experimental setup involving a dielectric slab of
refractive index n, a vibrating mirror placed a short distance behind the slab,
a collimated, monochromatic light beam illuminating the mirror through the
slab, and an interferometer to measure the phase of the reflected beam, is all
that is needed to deduce the precise magnitude of the radiation pressure on a
submerged mirror. In the proposed experiment, the transparent slab plays the
role of the submerging liquid (even though it remains detached from the mirror
at all times), and the adjustable gap between the mirror and the slab simulates
the variable phase-angle psi_0. The phase of the reflected beam, measured as a
function of time during one oscillation period of the mirror, then provides the
information needed to determine the gap-dependence of the reflected beam's
Doppler shift and, consequently, the radiation pressure experienced by the
mirror.Comment: 9 pages, 2 figures, 13 equation
Are we teaching our students what they need to know about ageing? Results from the National Survey of Undergraduate Teaching in Ageing and Geriatric Medicine
Introduction - Learning about ageing and the appropriate management of older patients is important for all doctors. This survey set out to evaluate what medical undergraduates in the UK are taught about ageing and geriatric medicine and how this teaching is delivered.
Methods – An electronic questionnaire was developed and sent to the 28/31 UK medical schools which agreed to participate.
Results – Full responses were received from 17 schools. 8/21 learning objectives were recorded as taught, and none were examined, across every school surveyed. Elder abuse and terminology and classification of health were taught in only 8/17 and 2/17 schools respectively. Pressure ulcers were taught about in 14/17 schools but taught formally in only 7 of these and examined in only 9. With regard to bio- and socio- gerontology, only 9/17 schools reported teaching in social ageing, 7/17 in cellular ageing and 9/17 in the physiology of ageing.
Discussion – Even allowing for the suboptimal response rate, this study presents significant cause for concern with UK undergraduate education related to ageing. The failure to teach comprehensively on elder abuse and pressure sores, in particular, may be significantly to the detriment of older patients
LMS Based Adaptive Channel Estimation for LTE Uplink
In this paper, a variable step size based least mean squares (LMS) channel estimation (CE) algorithm is presented for a single carrier frequency division multiple access(SC-FDMA) system under the umbrella of the long term evolution (LTE). This unbiased CE method can automatically adapts the weighting coefficients on the channel condition. Therefore, it does not require knowledge of channel,and noise statistics. Furthermore, it uses a phase weighting scheme to eliminate the signal fluctuations due to noise and decision errors. Such approaches can guarantee the convergence towards the true channel coefficient. The mean and mean square behaviors of the proposed CE algorithm are also analyzed. With the help of theoretical analysis and simulation results, we prove that the proposed algorithm outperforms the existing algorithms in terms of mean square error (MSE) and bit error rate (BER) by more than around 2.5dB
IMPACT OF A MORE INTENSIVE INSECT PEST INFESTATION LEVEL ON COTTON PRODUCTION: TEXAS HIGH PLAINS
This study evaluated implications of increased bollworm problems in a 20-county area of the Texas High Plains relative to cotton yields and economic impact. Results did not indicate a serious effect of bollworms upon lint yield when insecticides were used for control. However, estimated annual reduction in farmer profit due to the bollworm for 1979-81 was over $30 million. Yields were estimated to decline about 300,000 bales without insecticide use and about 30,000 bales with insecticide use. This decline suggests potentially serious implications for the comparative economic position of cotton in this region if insecticide resistance were to develop among insect pests.Crop Production/Industries,
Trouble with the Lorentz law of force: Incompatibility with special relativity and momentum conservation
The Lorentz law of force is the fifth pillar of classical electrodynamics,
the other four being Maxwell's macroscopic equations. The Lorentz law is the
universal expression of the force exerted by electromagnetic fields on a volume
containing a distribution of electrical charges and currents. If electric and
magnetic dipoles also happen to be present in a material medium, they are
traditionally treated by expressing the corresponding polarization and
magnetization distributions in terms of bound-charge and bound-current
densities, which are subsequently added to free-charge and free-current
densities, respectively. In this way, Maxwell's macroscopic equations are
reduced to his microscopic equations, and the Lorentz law is expected to
provide a precise expression of the electromagnetic force density on material
bodies at all points in space and time. This paper presents incontrovertible
theoretical evidence of the incompatibility of the Lorentz law with the
fundamental tenets of special relativity. We argue that the Lorentz law must be
abandoned in favor of a more general expression of the electromagnetic force
density, such as the one discovered by A. Einstein and J. Laub in 1908. Not
only is the Einstein-Laub formula consistent with special relativity, it also
solves the long-standing problem of "hidden momentum" in classical
electrodynamics.Comment: 7 pages, 1 figur
Adaptive responses to very low protein diets: The first comparison of ketoacids to essential amino acids
Adaptive responses to very low protein diets: The first comparison of ketoacids to essential amino acids. Eight patients with chronic renal failure (GFR 18.8 ± 2.7 ml/min) were randomized to a crossover comparison of a very low protein diet (VLPD) containing 0.28g protein and 35kcal per kg per day, plus an isomolar mixture of either ketoacids (KA) or essential amino acids (EAA). Subjects initiated the diets 14 days before hospital admission and following a four-day equilibration, a five-day nitrogen balance (BN) was performed. Whole-body protein turnover (WBPT) was measured during fasting and feeding using intravenous [1-13C]leucine and intragastric [5,5,5-2H3]leucine. Even though the VLPD/KA regimen contained 15% less nitrogen, BN was neutral and did not differ between the regimens. Nitrogen conservation with KA was due to a reduction in urea nitrogen appearance. Rates of WBPT measured during fasting and feeding did not differ between the KA or EAA regimens. During both regimens, feeding decreased protein degradation, whereas protein synthesis was unchanged. Although feeding stimulated leucine oxidation, rates were 50 to 100% lower than reported in CRF patients consuming 0.6 or 1.0g protein/kg/day. Thus, neutral BN with the VLPD regimen is achieved by a marked reduction in amino acid oxidation and a postprandial inhibition of protein degradation
Cornering the revamped BMV model with neutrino oscillation data
FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPUsing the latest global determination of neutrino oscillation parameters from [1] we examine the status of the simplest revamped version of the BMV (Babu-Ma-Valle) model, proposed in [2]. The model predicts a striking correlation between the "poorly determined" atmospheric angle 623 and CP phase Sep, leading to either maximal CP violation or none, depending on the preferred 623 octants. We determine the allowed BMV parameter regions and compare with the general three-neutrino oscillation scenario. We show that in the BMV model the higher octant is possible only at 99% C. L., a stronger rejection than found in the general case. By performing quantitative simulations of forthcoming DUNE and T2HK experiments, using only the four "well-measured" oscillation parameters and the indication for normal mass ordering, we also map out the potential of these experiments to corner the model. The resulting global sensitivities are given in a robust form, that holds irrespective of the true values of the oscillation parameters.774179182FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2014/05133-12014/19164-62015/16809-9Work supported by Spanish grants FPA2014-58183-P, SEV-2014-0398 (MINECO) and PROMETEOII/2014/084 (Generalitat Valenciana). P. P. was supported by FAPESP grants 2014/05133-1, 2015/16809-9, 2014/19164-6 and FAEPEX grant N. 2391/17
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