Asymmetrical performance of a laser-based reservoir computer with optoelectronic feedback.

We numerically quantify the performance of a photonic reservoir computer based on a semiconductor laser subject to high-pass filtered optoelectronic feedback. We assess its memory capacity, computational ability, and performance in solving a multi-step prediction task. By analyzing the complex bifurcation landscape of the corresponding delay-differential equation model, we observe that optimal performance occurs at the edge of instability, at the onset of periodic regimes, and unveil a parity asymmetry in the performance with a slight advantage for positive over negative feedback.

Bifurcation structure of a swept-source laser.

We numerically analyze a delay differential equation model of a short-cavity semiconductor laser with an intracavity frequency-swept filter and reveal a complex bifurcation structure responsible for the asymmetry of the output characteristics of this laser. We show that depending on the direction of the frequency sweep of a narrow-band filter, there exist two bursting cycles determined by different parts of a continuous-wave solutions branch.

Laser fabrication of crystalline silicon nanoresonators from an amorphous film for low-loss all-dielectric nanophotonics.

The concept of high refractive index subwavelength dielectric nanoresonators, supporting electric and magnetic optical resonance, is a promising platform for waveguiding, sensing, and nonlinear nanophotonic devices. However, high concentration of defects in the nanoresonators diminishes their resonant properties, which are crucially dependent on their internal losses. Therefore, it seems to be inevitable to use initially crystalline materials for fabrication of the nanoresonators. Here, we show that the fabrication of crystalline (low-loss) resonant silicon nanoparticles by femtosecond laser ablation of amorphous (high-loss) silicon thin films is possible. We apply two conceptually different approaches: recently proposed laser-induced transfer and a novel laser writing technique for large-scale fabrication of the crystalline nanoparticles. The crystallinity of the fabricated nanoparticles is proven by Raman spectroscopy and electron transmission microscopy, whereas optical resonant properties of the nanoparticles are studied using dark-field optical spectroscopy and full-wave electromagnetic simulations.

[Epidemiological and molecular biological analysis of causes of rise of hepatitis A incidence in Republic of Tuva in 2008].

AIM: Analysis of hepatitis A (HA) incidence in Tyva Republic in 2008 exploiting traditional epidemiological and molecular methods. MATERIALS AND METHODS: Epidemiological analysis of HA cases and contact persons in Erzinsky and Kyzyl regions of Tyva Republic was performed. Class M and G antibodies to HAV were determined in serum samples (n = 28), and HAV RNA--in stool samples (n = 16). Phylogenetic analysis of HAV RNA sequence was performed for VP1/2A region of the HAV genome with length 394 nucleotides. RESULTS: Cases of HA were registered during 3.5 months. Water supply sources did not have deviations from established standards. According to results of interviews, common food factor, which was able to cause the rise of HA incidence, was not determined. Signs of fecal contamination were revealed on environmental objects in preschool institutions and schools that demonstrate the low level of hygienic behaviour. It was shown that all cases of HA are related with different variants of the virus belonged to genotype IA that points to the absence of common source of infection. CONCLUSION: Results of epidemiological and genetic analysis of HAV demonstrate that observed rise in HA incidence in Tyva Republic are connected with phase of seasonal rise of HA incidence, which is characteristic for its perennial dynamics with active realization of contact route of virus transmission.

[GBV-C infection in HIV-infected patients in the Russian Federation].

The spread and genotypical variability of GBV-C virus were determined among the HIV-positive patients in the Russian Federation. More than a fourth (26.2%) of the HIV-infected patients were shown to have GBV-C coinfection; all virus isolates belonged to genotype 2 with a predominance of subtype 2a. Analysis of the impact of GBV-C coinfection on HIV burden and CD4 lymphocyte levels showed no significant impact on these basic characteristics of HIV infection. However, coinfection with GBV-C and HIV was associated with the higher frequency of undetectably low ( < 400 copies/ml) of HIV burden, which enables GBV-C infection to be regarded as a potentially favorable factor in HIV infection.

Yeast telosome complex: components and their functions.

Telomeres are multi-component DNA-protein complexes protecting linear chromosome termini against degradation and fusion. Telomeres and their components are involved in many essential processes: control of cell division number, regulation of transcription, reparation. They are necessary for correct chromosome segregation during cell division. Telomere protein content and DNA length are under control of different factors, such as components of replication and reparation machinery and cell division cycle kinases. Here we discuss the participation of components of yeast telomere (telosome complex) in different cellular processes, telomeric DNA length regulation pathways, and some issues of telosome evolution.

A specific DNA-dependent DNA polymerase is associated with Saccharomyces cerevisiae telomerase.

The telomere DNA of most eucaryotes consists of tandem DNA repeats and a number of associated proteins. The synthesis of the G-rich DNA strand is performed by the telomerase complex. The complementary C-strand is synthesized by DNA-dependent DNA polymerases. Using telomerase reverse transcriptase tagging followed by immunoprecipitation coupled with two-step purification, we have found a specific DNA-dependent DNA polymerase activity associated with telomerase of Saccharomyces cerevisiae. Investigation of the biochemical properties of this DNA polymerase activity confirms the hypothesis of tight interaction of DNA polymerase delta with telomerase.

Attitudes towards organ donation and transplantation--a study involving Baltic physicians.

The aim of this study was to identify and describe attitudes towards organ donation and transplantation among a group of Baltic physicians who are involved in this aspect of medical care. A total of 151 neurosurgeons, anesthesiologists, and neurologists anonymously answered a questionnaire between February and March 1995. The majority of physicians said they would be willing to donate their own organs after their death but disagreed with the idea of using organs from a dead person who had had a negative opinion towards organ donation. Given a patient who fulfilled the criteria for brain death, this group of physicians found it widely acceptable to keep the patient on a ventilator until organ donation could take place. We conclude that the participating physicians generally have similar attitudes towards organ donation and transplantation. This study is valuable in that it shows the interest in, and the need for, clinical and research collaboration, including a discussion of ethics, within the area of organ donation and transplantation. This is essential for future collaboration with Western countries.