Anti-Stokes femtosecond photon echo in dye-doped polymer films and the possibility of coherent optical cooling

An anti-Stokes model is proposed to explain the known experimental data on the femtosecond photon echo in dye-doped polymer films at room temperature. The possibility of implementing the anti-Stokes mode of coherent laser cooling of such films is analyzed. © Allerton Press, Inc. 2008

Femtosecond photon echo in a dye-doped polymer film and the possibility of coherent optical cooling

The signals of primary and stimulated femtosecond photon echoes are investigated in a dye-doped polymer film at room temperature. The homogeneous S 0 → S 1 spectral line width, which is due to the interaction between the impurity molecules and the quasi-local low-frequency modes, is estimated (≈5 × 10 12 Hz). Special attention is paid to the study of spectra of femtosecond echo signals. The short-wave shifts of these spectra, with respect to the spectrum of femtosecond exciting pulses, are observed. These shifts indicate that the anti-Stokes regime of femtosecond pulse emission is realized. Therefore, the coherent regime of laser cooling of solids appears to be possible. The prospects of using of this new cooling regime in the function of a solid-state optical refrigerator are discussed. © Nauka/Interperiodica 2007

A new technique for laser cooling with superradiance

We present a new theoretical scheme for laser cooling of rare earth doped solids with optical super-radiance (SR), which is the coherent, sharply directed spontaneous emission of photons by a system of laser excited rare earth ions in the solid state host (glass or crystal). We consider an Yb3+ doped ZBLAN sample pumped at the wavelength 1015 nm with a rectangular pulsed source with a power of ~433W and duration of 10ns. The intensity of the SR is proportional to the square of the number of excited ions. This unique feature of SR permits a dramatic increase in the rate of the cooling process in comparison with the traditional laser cooling of the rare earth doped solids with anti-Stokes spontaneous incoherent radiation (fluorescence). This scheme overcomes the limitation of using only low phonon energy hosts for laser cooling.Comment: 10 pages,6 figure

Prevalence and risk factors of major depressive disorder in HIV/AIDS as seen in semi-urban Entebbe district, Uganda

BACKGROUND: Not much is known about the risk factors of major depressive disorder (MDD) in HIV/AIDS in the African socio-cultural context. Therefore a study was undertaken to examine the prevalence and risk factors of MDD in HIV/AIDS in semi-urban Uganda. METHODS: A cross-sectional study was undertaken among 618 respondents attending two HIV clinics in Uganda. RESULTS: Prevalence of MDD was 8.1%. Factors associated with MDD at univariate analysis only were female gender, family history of mental illness, negative coping style, alcohol dependency disorder, food insecurity and stress; not associated with MDD were social support, neurocognitive impairment, CD4 counts and BMI. Factors independently associated with MDD were psychosocial impairment, adverse life events, post traumatic stress disorder, generalised anxiety disorder and life-time attempted suicide. CONCLUSION: Psychological and social factors were the main risk factors of MDD among ambulatory HIV positive persons with no evidence for the role of the neurotoxic effects of HIV. Treatment approaches for MDD in this patient group should be modeled on those used among non-HIV groups

The functions of the legal model of the real state circulation system

Objective: to analyze the concept of legal modeling in the field of real estate circulation as a method of scientific research. Methods: abstract logic and method of comparative analysis. Results: The principles are proposed for the functioning of the legal system model of the real estate circulation; the author reveals approaches to the definition of "real estate object". Scientific novelty: The research of the content of the "real estate object" notion resulted in the classification of the legal model of the real estate circulation system; revealed the structure of the circulation mechanism, including legal procedure. Practical value: The approaches were developed to define the individual elements of the legal model of real estate circulation system; the conclusion is made that the concept of "legal model" differs from the related categories. Such a notion, in all cases, has the function of legal modeling and is instrumental in nature

Definitions of the real estate turnover system

Objective to study the principles and the role of legislative definitions within the various research methods for modeling functions of legal models of the civil rights objects. Methods method of comparative analysis and abstract method. Results the analysis of scientific approaches defines simulation as a method of research which remains weak in legal sciences its relevance and topicality are ignored. Scientific novelty the modeling principles in the theory of law are not fully established in connection with which the author gives the definition of the legal modeling factors in the sphere of the turnover of the civil rights objects and their classification. Practical value the identified approaches provide for the possibility to study the principles of development of the approaches functioning mechanism as well as to map the ideal model with really existing social relations in the sphere of real estate turnover. In addition the author proposes systematization of real contracts as to their content ndash the type of property rights the transfer of which is the subject of agreement. The work expands the concept of quotproperty lawquot in statics as a result of comparison of the quotlegal modelquot concept with other similar terms. The conclusion is made about the existence of separate legal category in modern science

CLASSIFICATION OF THE LEGAL MODEL OF REAL ESTATE CIRCULATION SYSTEM

Objective: to investigate the principles and role of the legislative definition in the various research methods for modeling the function of legal model of civil rights objects. Methods: abstract-logical and comparative analysis. Results: the analysis of scientific approaches defines modeling as a method of research that remains insufficiently used in the legal sciences, in spite of its relevance and topicality. Scientific novelty: modeling principles are not well established in the theory of law, thus the author's definition is proposed of legal modeling factors in the sphere of civil rights objects turnover and classification. Practical value: the identified approaches include the possibility of learning the principles of development of their functioning mechanism, as well as comparison of the ideal model with actually existing social relations in the sphere of real estate turnover

Anti-Stokes femtosecond photon echo in dye-doped polymer films and the possibility of coherent optical cooling

An anti-Stokes model is proposed to explain the known experimental data on the femtosecond photon echo in dye-doped polymer films at room temperature. The possibility of implementing the anti-Stokes mode of coherent laser cooling of such films is analyzed. © Allerton Press, Inc. 2008

Anti-Stokes femtosecond photon echo in dye-doped polymer films and the possibility of coherent optical cooling

An anti-Stokes model is proposed to explain the known experimental data on the femtosecond photon echo in dye-doped polymer films at room temperature. The possibility of implementing the anti-Stokes mode of coherent laser cooling of such films is analyzed. © Allerton Press, Inc. 2008