Orthogonality relations are given for the ``four-vector'' guided modes of anisotropic uniform wave guides and for the ``six-vector'' guided modes of uniform wave guides containing unidirectional electron beams with axially independent dc velocities. In general, these orthogonality relations involve both the modes of the given wave guide and those of an appropriate ``adjoint'' wave guide. A description is given for the adjoint wave guides associated with wave guides which contain media whose characteristics are restricted only by the requirement that they be axially independent and which, if bounded, are subject to a variety of boundary conditions arising from idealizations of actual boundaries.
Experimental observations of a new regime of whistler propagation in the laboratory are reported in this paper. The experiments are carried out in a large laboratory unbound uniform plasma with a density of ne ∼ 109–1011 cm−3 and a magnetic field of 1–20 G. Studies are performed in the electron magnetohydrodynamic regime, which is governed by electron dynamics with Le ≪ L ≪ Li and τci ≫ τ ≫ τce, where L and τ are the spatial and temporal scale lengths of the perturbations, Le and Li the electron and ion Larmor radii, respectively, and τci and τce the temporal scales corresponding to the ion gyrofrequency and electron gyrofrequency, respectively. The complete topology of the perturbed wave magnetic field is unravelled by mapping it on a two dimensional grid over repeated plasma shots. It is observed that the excited waves are elongated whistlers in the propagation direction. However, in the perpendicular direction, the extent is limited to scale lengths of the order of natural scale length of plasma, i.e., the skin depth (∼c/ωpe), rather than being oblique as predicted by theory and observed in other experiments. The wave shows a feeble resonance cone at an angle of ∼10° but no obliqueness. Also, the secondary induction, which helps the wave to propagate further into the plasma, does not manifest within the spatial scale lengths characteristic to this regime. However, the wave is still able to maintain the whistler speed calculated for the given plasma and pulsed current parameters. It is speculated that the natural scale length (skin depth) and in turn the electron inertia may play a significant role, leading to the observed results. A physical model is also presented that could possibly explain the observed phenomena.
Context:Nutritional status is a sensitive indicator of community health and nutrition. There is a growing realization that adequate nutrition is a necessary first step in the improvement of quality of life. Malnutrition and infection are connected by a vicious cycle. It is one of the greatest international health problems and the biggest challenges being faced today. Thus, to know the magnitude of undernutrition among preschool children and to find out the sensitive tool for detection of undernutrition, this study was conducted among children under - 5 years of age.Aims:To assess the validity of the nutritional indices for screening malnutrition.Settings and Designs:The study was a community-based, cross-sectional survey carried out in the catchment area of Rural Health Training Center, Rohilkhand Medical College, Bareilly.Subjects and Methods:Various anthropometric criteria like, Kanawati, McLaren, Rao, Dugdale and weight for age according to the Indian Academy of Pediatrics (IAP) (modified Gomez) classification were used to define nutritional status.Statistical Analysis Used:Data were entered and analyzed in SPSS and receiver operating characteristic (ROC) curves (sensitivity vs. 1 - specificity) were calculated for all the above mentioned indices.Results:Age dependent criteria such as IAP (48.2% malnourished) and McLaren (48.3% malnourished) were followed by the age independent criteria such as Kanawati (74.3% malnourished), Dugdale (45.5% malnourished), and Rao (33.1% malnourished) to classify the mild to moderate malnutrition. ROC showed Dugdale as the best index for the judgement of malnutrition showing maximum area under the curve.Conclusions:Malnutrition being a public health problem leads to morbidity which is a vicious cycle and needs proper attention to curb its detrimental effect on the children.
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