Statistical models of economic burden : a case study in medicine

Purpose: The main aim of this article is to use statistical methods for the estimation of the economic burden and the survival rate of deeply premature babies. Design/Methodology/Approach: The results of a survey of 2.222 children with a birth weight of 501-1500 grams and a gestational age of 23-37 weeks were used as input data. Cox’s proportional hazards model was used as a survival tool. Findings: The results of Cox survival regression model showed a series of statistically significant predictors of survivability (p<0.05) for three age cohorts: neonatal, postnatal and pediatric (until 2 years). One of the statistically significantly predictors of survivability of premature infants with very low birth weight (VLBW) and extremely low birth weight (ELBW) in every age cohort is the volume of primary resuscitation measure and the length of stay in the neonatal pathology unit (NPU). Practical Implications: The results permitted to assess the amount of nursing care measures, the duration of care in a neonatal pathology unit, the rehabilitation of children with VLBW and ELBW in the long run. The assessment will ultimately help to estimate the overall economic burden associated with maintaining health and quality of life of premature babies. Originality/Value: The scientific contribution of the study consists in the use of an integrated approach to the problem of estimating the economic burden of nursing very premature babies, taking into account their survival and subsequent disability risks in the neonatal, postnatal, and pediatric periods.peer-reviewe

Scattering of the near field of an electric dipole by a single-wall carbon nanotube

The use of carbon nanotubes as optical probes for scanning near-field optical microscopy requires an understanding of their near-field response. As a first step in this direction, we investigated the lateral resolution of a carbon nanotube tip with respect to an ideal electric dipole representing an elementary detected object. A Fredholm integral equation of the first kind was formulated for the surface electric current density induced on a single-wall carbon nanotube (SWNT) by the electromagnetic field due to an arbitrarily oriented electric dipole located outside the SWNT. The response of the SWNT to the near field of a source electric dipole can be classified into two types, because surface-wave propagation occurs with (i) low damping at frequencies less than ~ 200-250 THz and (ii) high damping at higher frequencies. The interaction between the source electric dipole and the SWNT depends critically on their relative location and relative orientation, and shows evidence of the geometrical resonances of the SWNT in the low-frequency regime. These resonances disappear when the relaxation time of the SWNT is sufficiently low. The far-field radiation intensity is much higher when the source electric dipole is placed near an edge of SWNT than at the centroid of the SWNT. The use of an SWNT tip in scattering-type scanning near-field optical microscopy can deliver a resolution less than ~ 20 nm. Moreover, our study shows that the relative orientation and distance between the SWNT and the nanoscale dipole source can be detected.Comment: 23 pages, 16 figure

Microscopic theory of quantum dot interactions with quantum light: local field effect

A theory of both linear and nonlinear electromagnetic response of a single QD exposed to quantum light, accounting the depolarization induced local--field has been developed. Based on the microscopic Hamiltonian accounting for the electron--hole exchange interaction, an effective two--body Hamiltonian has been derived and expressed in terms of the incident electric field, with a separate term describing the QD depolarization. The quantum equations of motion have been formulated and solved with the Hamiltonian for various types of the QD excitation, such as Fock qubit, coherent fields, vacuum state of electromagnetic field and light with arbitrary photonic state distribution. For a QD exposed to coherent light, we predict the appearance of two oscillatory regimes in the Rabi effect separated by the bifurcation. In the first regime, the standard collapse--revivals phenomenon do not reveal itself and the QD population inversion is found to be negative, while in the second one, the collapse--revivals picture is found to be strongly distorted as compared with that predicted by the standard Jaynes-Cummings model. %The model developed can easily be extended to %%electromagnetic excitation. For the case of QD interaction with arbitrary quantum light state in the linear regime, it has been shown that the local field induce a fine structure of the absorbtion spectrum. Instead of a single line with frequency corresponding to which the exciton transition frequency, a duplet is appeared with one component shifted by the amount of the local field coupling parameter. It has been demonstrated the strong light--mater coupling regime arises in the weak-field limit. A physical interpretation of the predicted effects has been proposed.Comment: 14 pages, 7 figure

Spontaneous decay of an emitter's excited state near a finite-length metallic carbon nanotube

The spontaneous decay of an excited state of an emitter placed in the vicinity of a metallic single-wall carbon nanotube (SWNT) was examined theoretically. The emitter-SWNT coupling strongly depends on the position of the emitter relative to the SWNT, the length of the SWNT, the dipole transition frequency and the orientation of the emitter. In the high-frequency regime, dips in the spectrum of the spontaneous decay rate exist at the resonance frequencies in the spectrum of the SWNT conductivity. In the intermediate-frequency regime, the SWNT conductivity is very low, and the spontaneous decay rate is practically unaffected by the SWNT. In the low-frequency regime, the spectrum of the spontaneous decay rate contains resonances at the antennas resonance frequencies for surface-wave propagation in the SWNT. Enhancement of both the total and radiative spontaneous decay rates by several orders in magnitude is predicted at these resonance frequencies. The strong emitter-field coupling is achieved, in spite of the low Q factor of the antenna resonances, due to the very high magnitude of the electromagnetic field in the near-field zone. The vacuum Rabi oscillations of the population of the excited emitter state are exhibited when the emitter is coupled to an antenna resonance of the SWNT.Comment: 8 pages, 6 figure

Spontaneous decay of excited atomic states near a carbon nanotube

Spontaneous decay process of an excited atom placed inside or outside (near the surface) a carbon nanotube is analyzed. Calculations have been performed for various achiral nanotubes. The effect of the nanotube surface has been demonstrated to dramatically increase the atomic spontaneous decay rate -- by 6 to 7 orders of magnitude compared with that of the same atom in vacuum. Such an increase is associated with the nonradiative decay via surface excitations in the nanotube.Comment: 8 pages, 3 figure

ЛАНДШАФТНО-ЕКОЛОГІЧНЕ ПЛАНУВАННЯ, ЯК ВТІЛЕННЯ ЕКОЛОГІЧНОГО ІМПЕРАТИВУ

The analysis of modern situation is done in the system of the landscape planning of territories, taking into account an existent legislative base. The special attention is paid to Law of Ukraine «About landscapes», high-quality development of which and adequate realization would allow to optimize the processes of the landscape planning for providing realization of ecological imperative of steady development.Зроблено аналіз сучасної ситуації в системі ландшафтного планування територій з огляду на чинну законодавчу базу. Особлива увага приділена Закону України «Про ландшафти», якісна розробка якого і адекватна реалізація дали б можливість оптимізувати процеси ландшафтного планування для забезпечення реалізації екологічного імперативу сталого розвитку