Results 21 to 30 of about 19,874 (215)
Variation in dosimeter calibration factor (Ndw) over a period of 20 years
Journal of Medical Physics, 2021 Long delays in renewal of calibration of secondary standards radiation dosimeters in radiation oncology centers due to the COVID19 pandemic have aroused concerns regarding accuracy in dose delivery to patients.
Manoj Kumar Semwal +4 more
doaj +1 more source
A note on almost periodic variational equations [PDF]
Communications on Pure and Applied Analysis, 2011 The variational equation of a nonautonomous differential equation (x) over dot = F(t, x) along a solution mu is given by (x) over dot = DxF(t, mu(t))x. We consider the question whether the variational equation is almost periodic provided that the original equation is almost periodic by a discussion of the following problem: Is the derivative DxF almost
Giesl, Peter, Rasmussen, Martin
openaire +1 more source
Ecological Indicators, 2021 The Shiyang River Basin is a typical arid watershed in Northwest China. Scientific understanding of the driving mechanism of runoff change is the basis of scientific utilization of water resources and regional sustainable development.
Dongxiang Xue +7 more
doaj +1 more source
Variational Calculation of the Period of Nonlinear Oscillators [PDF]
Journal of Statistical Physics, 2004 The problem of calculating the period of second order nonlinear autonomous oscillators is formulated as an eigenvalue problem. We show that the period can be obtained from two integral variational principles dual to each other. Upper and lower bounds on the period can be obtained to any desired degree of accuracy.
Benguria Donoso, Rafael +1 more
openaire +7 more sources
The variation of the average water flow from the Căliman Mountains [PDF]
Riscuri şi Catastrofe, 2021 The variation of river water runoff is a normal phenomenon, given the close link between runoff and atmospheric precipitation, both components of the water balance.
C. HÎRLAV
doaj +1 more source
The runoff variation characteristics of Dongting Lake, China
Tecnología y ciencias del agua, 2017 Mao, D., Feng, C., Zhou, H., Hu, G., Li, Z., & Guo, R. (MarchApril, 2017). The runoff variation characteristics of Dongting Lake, China. Water Technology and Sciences (in Spanish), 8(2), 77-91.
Mao Dehua +5 more
doaj +1 more source
Annual molt period and seasonal color variation in the Eared Dove´s crown.
PLoS ONE, 2023 Molting is an important process in which old and worn feathers are exchanged for new ones. Plumage color is determined by pigments such as carotenes, melanin and by the ultrastructure of the feather.
Diego J Valdez +1 more
doaj +1 more source
Temporal and spatial dynamics of gastrointestinal parasite infection in Père David’s deer [PDF]
PeerJ, 2021 Background The Père David’s deer (Elaphurus davidianus) population was established from only a small number of individuals. Their genetic diversity is therefore relatively low and transmissible (parasitic) diseases affecting them merit further attention.
Shanghua Xu +8 more
doaj +2 more sources
The Onset of Quasi-Periodic Variations in Be Stars [PDF]
Astrophysics and Space Science, 1993 We present some evidence of the quasi-periodic long-term variations (QPLV) in the violet-to-red ratio of double-peaked emission lines (V/R variation) and/or in the radial velocities of shell absorption lines for some Be stars. Although the V/R variations are rather prevailing phenomena among Be stars, the QPLV is remarkable by the following ...
T. Kogure, M. Mon, M. Suzuki
openaire +1 more source
A Variational Approach to the Stability of Periodic Peakons [PDF]
Journal of Nonlinear Mathematical Physics, 2004 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire +2 more sources