Search for Millicharged Particles at SLAC

Particles with electric charge q < 10^(-3)e and masses in the range 1--100 MeV/c^2 are not excluded by present experiments. An experiment uniquely suited to the production and detection of such "millicharged" particles has been carried out at SLAC. This experiment is sensitive to the infrequent excitation and ionization of matter expected from the passage of such a particle. Analysis of the data rules out a region of mass and charge, establishing, for example, a 95%-confidence upper limit on electric charge of 4.1X10^(-5)e for millicharged particles of mass 1 MeV/c^2 and 5.8X10^(-4)e for mass 100 MeV/c^2.Comment: 4 pages, REVTeX, multicol, 3 figures. Minor typo corrected. Submitted to Physical Review Letter

Improvement of Existing Adequacy Indices on the Example of the Murmansk Region Power System

На основании СТО "Методические указания по проведению расчетов балансовой надежности" проведено усовершенствование существующих показателей балансовой надежности. Расчеты выполнены на примере модели энергосистемы Мурманской области. Результаты получены в ходе расчета в ПК RastrWin3, а также пакете Matpower программы Matlab. Произведен анализ уже существующих показателей балансовой надежности, а также предложены новые показатели.Existing adequacy indices based on the standard "Methodical instructions for adequacy analysis in power systems” were proposed to be improved. The calculations were carried out on the model of power system of the Murmansk region. The results were obtained using RastrWin3 software and Matpower package of the Matlab software. The adequacy analysis was carried out, and new forms of indices were proposed

Dysbarism. High-altitude illness

Dysbarism is the collective term used to describe the pathologic changes that occur when the human body is exposed to environmental pressure changes (alternobaric exposure). Those altered pressures are translated into unphysiologic behavior of gases in organs and tissues. Failure to adequately or timely adapt to those changes, can generate (depending on a number of exposure and individual factors) the different clinical syndromes of dysbarism. Alternobaric exposure is a concern in a number of occupational and recreational activities, such as diving, compressed air work (as in tunnel construction and caisson work), as well as in aviation, mountain climbing, and high-altitude flying

Search for exchange-antisymmetric two-photon states

Atomic two-photon J=0 $\leftrightarrow$J'=1 transitions are forbidden for photons of the same energy. This selection rule is related to the fact that photons obey Bose-Einstein statistics. We have searched for small violations of this selection rule by studying transitions in atomic Ba. We set a limit on the probability $v$ that photons are in exchange-antisymmetric states: $v<1.2\cdot10^{-7}$.Comment: 5 pages, 4 figures, ReVTeX and .eps. Submitted to Phys. Rev. Lett. Revised version 9/25/9

Massive Electrodynamics and Magnetic Monopoles

Including torsion in the geometric framework of the Weyl-Dirac theory we build up an action integral, and obtain from it a gauge covariant (in the Weyl sense) general relativistic massive electrodynamics. Photons having an arbitrary mass, electric, and magnetic currents (Dirac's monopole) coexist within this theory. Assuming that the space-time is torsionless, taking the photons mass zero, and turning to the Einstein gauge we obtain Maxwell's electrodynamics.Comment: LaTex File, 9 pages, no figure

Millisecond-range electron spin memory in singly-charged InP quantum dots

We report millisecond-range spin memory of resident electrons in an ensemble of InP quantum dots (QDs) under a small magnetic field of 0.1 T applied along the optical excitation axis at temperatures up to about 5 K. A pump-probe photoluminescence (PL) technique is used for optical orientation of electron spins by the pump pulses and for study of spin relaxation over the long time scale by measuring the degree of circular polarization of the probe PL as a function of pump-probe delay. Dependence of spin decay rate on magnetic field and temperature suggests two-phonon processes as the dominant spin relaxation mechanism in this QDs at low temperatures.Comment: 3 pages, 4 figures, submitted to Appl. Phys. Let

Aplicarea sistemului de hidrochirurgie și a plasmajetului în debridarea toracoscopică a cavității pleurale la copii cu fibrinotorax

Toracoscopia a devenit o modalitate favorizată în tratamentul empiemului pleural la copii. Cu toate acestea, factorii care afectează rezultatul administrării toracoscopice rămân neclari. Scopul studiului este de a demonstra eficiența sistemului de hidrochirurgie "Versajet" și a unității de plasmă "Plasmajet" în tratamentul toracoscopic al copiilor cu complicații pleurale ale pneumoniei. MATERIALE SI METODE. În perioada 2015-2017, la Spitalul de Copii Speransky din Moscova, 377 copii cu pneumonie au fost tratați, la 62 pacienți (16,45%) din 377 am efectuat drenajul cavității pleurale, 14 pacienți cu vârste cuprinse între 1,6 și 15 ani (în medie, 3,2 ± 3,8 ani) cu empiem pleural au fost operați. S-a efectuat decorticarea pulmonară toracoscopică cu sistem de hidrochirurgie (Versajet-2). Sistemul hidrochirurgical este un instrument chirurgical bazat pe impactul jetului de apă de mare viteză asupra țesuturilor necrotice și inflamate, combinând avantajele debridării țesuturilor moi și evacuarea acestora prin pulsarea jetului de apă. Designul tubului de evacuare și apropierea acestuia de jetul lichid creează un vacuum local, care îndepărtează efectiv fibrina și conținutul lichid prin efectul Bernulli. Consimțământul informat a fost obținut de la toți părinții înainte de operare, iar procedura însăși a fost aprobată de comitetul de etică locală. REZULTATE. Recuperarea și reabilitarea fără particularități au fost în 13 cazuri. La un pacient cu empiem al cavității pleurale pe dreapta și leziune organică severă a sistemului nervos central a perioadei postoperatorii după o toracoscopie convențională complicată de recurența empiemului pleural.Retoracoscopia cu debridarea cavității pleurale de către sistemul de hidrochirurgie efectuată la șase zile după operația inițială, a avut rezultate satisfăcătoare. În cazul hemoragiei intraoperatorii, a fost efectuată coagularea plasmei de argon, obținându-se aerostasie completă la 2 pacienți și hemostază - la 1 pacient. Durata medie de funcționare a fost de 90 de minute (± 15 minute). Drenajul cavității pleurale este eliminat în ziua a 3-a sau a 4-a după operație. Copiii externați în ziua a 10-a (± 1,2 zile). Examinarea cu ultrasunete și cu raze X la patru luni după intervenția chirurgicală a confirmat absența inflamației în parenchimul pulmonar și reexpansarea plină pulmonară la toți pacienții. CONCLUZIE. Aplicarea sistemului hidrochirurgical în timpul toracoscopiei asigură o debridare sigură și eficientă a cavității pleurale, decorticările plămânului fiind fără deteriorarea severă a parenchimului pulmonar și crearea condițiilor pentru reabilitarea precoce a plămânilor compromiși.Thoracoscopy became a favored modality in pediatric pleural empyema treatment. However, factors affecting outcome of thoracos- copic management remain unclear. The purpose of the study is to demonstrate efficiency of hydrosurgery system "Versajet" and plasma unit "Plasmajet" in thoracoscopic treatment of children with pleural complications of pneumonia. MATERIALS AND METHODS. During the period of 2015-2017 at the Speransky Children’s Hospital in Moscow 377 children with pneumonia were treated, in 62 patients (16.45%) of 377 we perform drainage of pleural cavity, 14 patients from 1.6 to 15 years of age (on average, 3.2 ± 3.8 years old) with pleural empyema were operated. Thoracoscopic lung decortication with hydrosurgery system (Versajet-2) was performed. Hydrosurgery system is a surgical instrument based on impact of high-speed jet of water on necrotic and inflamed tissues, combining the advantages of soft tissues debridement and evacuation them by pulsating water jet. Design of the evacuation tube and its proximity to liquid jet creates a local vacuum, which effectively removes fibrin and liquid contents by Ber- nulli effect. Informed consent was obtained from all parents before operation, and procedure itself received approval from the local ethics committee. RESULTS. Recovery and rehabilitation was uneventful in 13 cases. In one patient with empyema of right pleural cavity and severe organic lesion of central nervous system postoperative period after conventional toracoscopy complicated by recurrence of pleural empyema. Rethoracoscopy with debridement of pleural cavity by hydrosurgery system performed six days after initial operation, with satisfactory results. In the event of intraoperative air leak or hemorrhage, application of argon plasma coagulation had been performed achieving complete aerostasis in 2 patients and hemostasis - in 1 patient. Average operation time was 90 minutes (± 15 minutes). Drainage of the pleural cavity removed on the 3rd or 4th day after surgery. Children discharged from the hospital on 10th PO day (± 1.2 days). Ultrasound and X-ray examination four months after surgery confirmed the absence of inflammation in the lung parenchyma and full lung reexpansion in all patients. CONCLUSION. Application of hydrosurgycal system during thoracoscopy provides safe and effective debridement of pleural cavity, decortications of the lung without severe damage to the lung parenchyma and create conditions for early rehabilitation of compro- mised lung

Algebraic structure of the Green's ansatz and its q-deformed analogue

The algebraic structure of the Green's ansatz is analyzed in such a way that its generalization to the case of q-deformed para-Bose and para-Fermi operators is becoming evident. To this end the underlying Lie (super)algebraic properties of the parastatistics are essentially used.Comment: plain TeX, Preprint INRNE-TH-94/4, 13

Cosmology and New Physics

A comparison of the standard models in particle physics and in cosmology demonstrates that they are not compatible, though both are well established. Basics of modern cosmology are briefly reviewed. It is argued that the measurements of the main cosmological parameters are achieved through many independent physical phenomena and this minimizes possible interpretation errors. It is shown that astronomy demands new physics beyond the frameworks of the (minimal) standard model in particle physics. More revolutionary modifications of the basic principles of the theory are also discussed.Comment: 37 pages, 5 figures; lectures presented at 9th International Moscow School of Physics (34th ITEP Winter School