Universal description of the rotational-vibrational spectrum of three particles with zero-range interactions

A comprehensive universal description of the rotational-vibrational spectrum for two identical particles of mass $m$ and the third particle of the mass $m_1$ in the zero-range limit of the interaction between different particles is given for arbitrary values of the mass ratio $m/m_1$ and the total angular momentum $L$. If the two-body scattering length is positive, a number of vibrational states is finite for $L_c(m/m_1) \le L \le L_b(m/m_1)$, zero for $L>L_b(m/m_1)$, and infinite for $L<L_c(m/m_1)$. If the two-body scattering length is negative, a number of states is either zero for $L \ge L_c(m/m_1)$ or infinite for $L<L_c(m/m_1)$. For a finite number of vibrational states, all the binding energies are described by the universal function $\epsilon_{LN}(m/m_1) = {\cal E}(\xi, \eta)$, where $\xi=\displaystyle\frac{N-1/2}{\sqrt{L(L + 1)}}$, $\eta=\displaystyle\sqrt{\frac{m}{m_1 L (L + 1)}}$,and $N$ is the vibrational quantum number. This scaling dependence is in agreement with the numerical calculations for $L > 2$ and only slightly deviates from those for $L = 1, 2$. The universal description implies that the critical values $L_c(m/m_1)$ and $L_b(m/m_1)$ increase as $0.401 \sqrt{m/m_1}$ and $0.563 \sqrt{m/m_1}$, respectively, while a number of vibrational states for $L \ge L_c(m/m_1)$ is within the range $N \le N_{max} \approx 1.1 \sqrt{L(L+1)}+1/2$

Geological and Geomechanical Model of the Verkhnekamsk Potash Deposit Site

Major accidents at OJSC Uralkali raised the question of the need for a detailed study of the geological structure of the Verkhnekamskoye potassium salt deposit, the identification of anomalous complex zones in the oversalt rocks and, above all, in the water-blocking layer (WBL). The article proposes a method for isolating weakened zones in the WBL and potash reservoirs, based on the combined use of geomechanical (laboratory core tests) and geophysical (acoustic broadband logging in wells and surface seismic exploration) studies. It also describes the method of zoning of WBLand potash reservoirs on the physical and mechanical properties to obtain their specific values. This technique will help solve the most urgent problem of ensuring industrial safety in the development of the Verkhnekamskoye potassium salt deposit (the safety of the WBL). The implementation of the proposed method is considered for the Romanovsky site of the Verkhnekamskoye deposits of potassium and magnesium salts. The research included 2D seismic explorations, physical and mechanical properties testing, and finding statistical dependencies between static and dynamic geomechanical parameters. Based on the processing of seismic materials and the obtained dependencies, a geological and geomechanical model of this area was created, and zones with different physicomechanical properties were identified

Spectropolarimetry of R Coronae Borealis in 1998--2003: Discovery of Transient Polarization at Maximum Brightness

We present an extended optical spectropolarimetry of R CrB from 1998 January to 2003 September. The polarization was almost constant in the phase of maximum brightness, being consistent with past observations. We detected, however, temporal changes of polarization ($\sim 0.5$ %) in 2001 March and August, which were the first detection of large polarization variability in R CrB near maximum brightness. The amplitude and the position angle of the `transient polarization' were almost constant with wavelength in both two events. There was a difference by about 20 degrees in the position angle between the two events. Each event could be explained by light scattering due to short-lived dust puff occasionally ejected off the line of sight. The flatness of the polarization against the wavelength suggests that the scatterer is a mixture of dust grains having various sizes. The rapid growth and fading of the transient polarization favors the phenomenological model of dust formation near the stellar photosphere (e.g., within two stellar radii) proposed for the time evolution of brightness and chromospheric emission lines during deeply declining periods, although the fading timescale can hardly be explained by a simple dispersal of expanding dust puff with a velocity of $\sim 200-350$ km s $^{-1}$. Higher expansion velocity or some mechanism to destroy the dust grains should be needed.Comment: 22 pages, 10 figures, accepted for publication in A

Experience in Utilization of Phylogenetic Analysis for Epidemiological Investigation of HIV Infection Case

Objective of the study was to investigate a criminal case of infection with HIV, applying molecular-genetic analysis of blood plasma samples from an estimated source of an infection and the recipient for evaluation of probability of epidemiological connection between them. Materials and methods. The study involved genotyping and phylogenetic analysis of nucleotide sequences of HIV-1 variants, isolated from patients in the investigated group and the control one (19 nucleotide sequences of the HIV-1 from the patients living in the Saratov region, and 15 nucleotide sequences from GenBank). Genotyping was performed using the commercial ViroSeq HIV-1 Genotyping System. The sub-typing of HIV-1 strains was carried out on-line, through the COMET HIV-1/2 and HCV and REGA HIV-1 Sybtyping Tool programs. Phylogenetic analysis of nucleotide sequences was carried out by Mega software, version 5.2. Phylogenetic trees were constructed; nucleotide distances were calculated by Kimura method (bootstrap level 1000). Results and conclusions. Virus variants, isolated from the studied samples, were defined as HIV-1 A subtype. Performed phylogenetic analysis showed that nucleotide sequences of the studied samples authentically grouped on the phylogenetic tree, forming a common cluster, which mismatched that of control group. Calculation of the genetic distance testifies that the genetic relation between the samples within the investigated group is higher, than between the same samples and those of the control group. Thus, by means of phylogenetic analysis it is shown that the strains received from an estimated source of infection and the recipient are genetically closer to each other, than to the strains from the group of comparison. In this regard, it is possible to claim with a big share of confidence that probability of epidemiological connection between them exists

Comparative evaluation of surgical methods for low invasive surgical treatment of diseases of the kidneys and urinary tract

Background. The rapid development of laparoscopic surgery can significantly reduce trauma during operations in the retroperitoneal space. These goals are also achieved by retroperitoneoscopy (RPS), which has become widespread in the last twenty years. The main difficulties for surgeons were associated with a small workspace and a lack of clear anatomical landmarks. Different access methods have different features, advantages and disadvantages, the analysis of which helps to optimize surgical treatment and accelerate patient rehabilitation.Aim: to study the advantages and disadvantages of retroperitoneoscopic and transperitoneal laparoscopic surgical methods of treatment.Materials and methods: We analyzed 305  case histories of patients operated on for various kidney diseases. The patients were divided into 2 groups: Group 1 – patients who underwent surgery using an extraperitoneal retroperitoneoscopic approach, Group 2 – patients who used the transperitoneal laparoscopic approach. A comparison of two methods of surgical treatment of kidney diseases, retroperitoneoscopic and laparoscopic access, was carried out. The following indicators were compared: duration of surgery, length of hospital stay, need for analgesics, frequency of postoperative complications.Results. The duration of the operation with retroperitoneoscopic surgery was reduced by more than 15 % compared with the laparoscopic approach. Shorter periods of pain relief were required, and the number of complications also decreased. The duration of inpatient treatment did not differ significantly.Conclusion. Retroperitoneoscopic approach can be used as the method of choice for operations on the retroperitoneal space

Paradox: Does liver insuffi ciency protect the patient? A hypothesis

Despite the fact that the key role of the liver in the formation of the immune response to injury is not in doubt, the mechanisms of weakening the immune response to infectious and noninfectious lesions in patients with hepatic failure remain unclear. We propose an original hypothesis of forming the ways to limit the amplitude of the systemic inflammatory response in patients with the end-stage liver disease. The basis of the hypothesis is the idea that as a result of reducing the intensity of the natural stimulation of membrane mCD14 receptors by the ligands of infectious nature, the basic mechanism of the systemic immune response induction by liver macrophages (Kupffer cells) is interrupted. According to the proposed hypothesis, in condition of liver failure, the synthesis of lipopolysaccharide-binding protein by hepatocytes is reduced. This leads to a decreased amplitude and intensity of the protective immune responses. This fact explains a number of clinical phenomena observed in patients with liver failure/dysfunction that consist in a reduced reactivity of the organism to the damage inflicted by infectious and noninfectious agents. The authors consider it possible to use this hypothesis in the search for new trends to prevent the immune system hyper-reactivity in sepsis, and to improve the therapeutic strategies for the management of patients at high risk of infectious complications after liver transplantation

Three-body recombination in Bose gases with large scattering length

An effective field theory for the three-body system with large scattering length is applied to three-body recombination to a weakly-bound s-wave state in a Bose gas. Our model independent analysis demonstrates that the three-body recombination constant alpha is not universal, but can take any value between zero and 67.9 \hbar a^4/m, where a is the scattering length. Other low-energy three-body observables can be predicted in terms of a and alpha. Near a Feshbach resonance, alpha should oscillate between those limits as the magnetic field B approaches the point where a -> infinity. In any interval of B over which a increases by a factor of 22.7, alpha should have a zero.Comment: 8 pages, RevTex, 3 postscript figures, uses epsf.sty, rotate.sty, references added, discussion improve