Distribution of xylem hydraulic resistance in fruiting truss of tomato influenced by water stress

In this study xylem hydraulic resistances of peduncles (truss stalk), pedicels (fruit stalk) and the future abscission zone (AZ) halfway along the pedicel of tomato (Lycopersicon esculentum L.) plants were directly measured at different stages of fruit development, in plants grown under two levels of water availability in the root environment. The xylem hydraulic connection between shoot and fruits has previously been investigated, but contradictory conclusions were drawn about the presence of a flow resistance barrier in the pedicel. These conclusions were all based on indirect functional measurements and anatomical observations of water-conducting tissue in the pedicel. In the present study, by far the largest resistances were measured in the AZ where most individual vessels ended. Plants grown at low water availability in the root environment had xylem with higher hydraulic resistances in the peduncle and pedicel segments on both sides of the AZ, while the largest increase in hydraulic resistance was measured in the AZ. During fruit development hydraulic resistances in peduncle and pedicel segments decreased on both sides of the AZ, but tended to increase in the AZ. The overall xylem hydraulic resistance between the shoot and fruit tended to increase with fruit development because of the dominating role of the hydraulic resistance in the AZ. It is discussed whether the xylem hydraulic resistance in the AZ of tomato pedicels in response to water stress and during fruit development contributes to the hydraulic isolation of fruits from diurnal cycles of water stress in the shoot

Современные методы идентификации возбудителя гонококковойинфекции

The authors present the data on the current laboratory methods and recommendations for identifying the gonorrhea pathogen applied in Russia and abroad: microscopy method, cultural (bacteriological) study method, nucleic acid amplification techniques and DNA chip technology. The benefits and shortcomings of each of the techniques have been compared. The authors emphasize the cultural method is currently considered to be the key one for diagnosing gonorrhea due to its high specificity and sensitivity making it possible to define the N.gonorrhoeae sensitivity to antimicrobial drugs, which is very important taking into consideration the N. gonorrhoeae resistance to antibiotics. The nucleic acid amplification techniques and, first of all, polymerase chain reaction, can be used in Russia as screening methods. The results obtained by using the techniques need confirmation by the cultural method.Приведены данные о современных лабораторных методах и рекомендациях по идентификации возбудителя гонореи, применяемых в России и за рубежом: методе микроскопии, культуральном (бактериологическом) методе исследования, методах амплификации нуклеиновых кислот, технологии ДНК-чипов; в сравнительном аспекте отражены достоинства и недостатки каждого метода. Подчеркнуто, что основой диагностики гонореи в настоящее время является культуральный метод, обладающий высокой специфичностью и чувствительностью, позволяющий определять чувствительность N. gonorrhoeae к антимикробным препаратам, что особенно актуально ввиду возрастания в последние годы резистентности N. gonorrhoeae к антибиотикам. Методы амплификации нуклеиновых кислот и прежде всего полимеразная цепная реакция в России могут применяться в качестве скрининговых методов; результаты, полученные при использовании этих методов, требуют подтверждения культуральным методом

Nonequilibrium Josephson current in ballistic multiterminal SNS-junctions

We study the nonequilibrium Josephson current in a long two-dimensional ballistic SNS-junction with a normal reservoir coupled to the normal part of the junction. The current for a given superconducting phase difference $\phi$ oscillates as a function of voltage applied between the normal reservoir and the SNS-junction. The period of the oscillations is $\pi \hbar v_F/L$, with $L$ the length of the junction, and the amplitude of the oscillations decays as $V^{-3/2}$ for $eV \gg \hbar v_{F}/L$ and zero temperature. The critical current $I_c$ shows a similar oscillating, decaying behavior as a function of voltage, changing sign every oscillation. Normal specular or diffusive scattering at the NS-interfaces does not qualitatively change the picture.Comment: Proceeding of MS2000, to appear in Physica

Nanostructured metal-fullerene field emission cathode

One of the important properties of carbon nanostructures is their cold electron emission ability. Carbon nanotubes and other nanostructures are capable of emitting high currents at relatively low electrical fields. They are already used in functional devices such as field emitters. The conventional method of carbon nanostructured cathodes manufacturing is thin film nanocarbon deposition using CVD process on electrically conducting substrate like metal or doped silicon plates. The alternative way of manufacturing of carbon field emission cathodes is based on a special processing of carbon microfibers or composite materials in metal holders. We used the similar approach to produce composite metal-nanocarbon material which may be easily processed and shaped to produce an effective field emission cathode which can be easily fixed an any environment. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2058

Ion generation by tungsten filament for pyroelectric pulsed accelerator

The article is devoted to investigation of ion generation by tungsten filament in vacuum. Electron and ion currents from tungsten filament at different residual air gas pressures are measured and compared. Dependencies of ion and electron currents from tungsten filament on its supply voltage are measured. Production of ions in the vicinity of the filament is discussed. Prospects of tungsten filament’s application in pyroelectric and piezoelectric pulsed accelerators are discussed.Стаття присвячена дослідженню генерації іонів вольфрамовою ниткою розжарення у вакуумі. Виміряні та порівняні струми електронів та іонів від вольфрамової нитки розжарення при різних тисках залишкового повітряного газу. Виміряні залежності іонного і електронного струмів від нитки розжарювання та її напруги живлення. Обговорюються утворення іонів у безпосередній близькості нитки розжарювання. Обговорюються перспективи застосування вольфрамової нитки розжарення в піроелектричному і п'єзоелектричному імпульсних прискорювачах.Статья посвящена исследованию генерации ионов вольфрамовой нитью накала в вакууме. Измерены и сравнены токи электронов и ионов от вольфрамовой нити накала при различных давлениях остаточного воздушного газа. Измерены зависимости ионного и электронного токов от нити накаливания и ее напряжения питания. Обсуждаются образование ионов в непосредственной близости нити накаливания. Обсуждаются перспективы применения вольфрамовой нити накала в пироэлектрическом и пьезоэлектрическом импульсных ускорителях

Nonequilibrium Josephson effect in mesoscopic ballistic multiterminal SNS junctions

We present a detailed study of nonequilibrium Josephson currents and conductance in ballistic multiterminal SNS-devices. Nonequilibrium is created by means of quasiparticle injection from a normal reservoir connected to the normal part of the junction. By applying a voltage at the normal reservoir the Josephson current can be suppressed or the direction of the current can be reversed. For a junction longer than the thermal length, $L\gg\xi_T$, the nonequilibrium current increases linearly with applied voltage, saturating at a value equal to the equilibrium current of a short junction. The conductance exhibits a finite bias anomaly around $eV \sim \hbar v_F/L$. For symmetric injection, the conductance oscillates $2\pi$-periodically with the phase difference $\phi$ between the superconductors, with position of the minimum ($\phi=0$ or $\pi$) dependent on applied voltage and temperature. For asymmetric injection, both the nonequilibrium Josephson current and the conductance becomes $\pi$-periodic in phase difference. Inclusion of barriers at the NS-interfaces gives rise to a resonant behavior of the total Josephson current with respect to junction length with a period $\sim \lambda_F$. Both three and four terminal junctions are studied.Comment: 21 pages, 19 figures, submitted to Phys. Rev.

Study of operating modes of STRAUS-R accelerator

The description of a pulsed electron accelerator STRAUS-R (3.5 MeV, 60 kA, 60 ns) and results of its experimental research for two operation modes are given. In the mode of electron beam focusing the accelerator provides the focal spot of 3-4 mm diameter on a target and maximum exposure dose of 27 R at 1-m distance from the output window. In the irradiating mode the maximum dose achieves 36 R at 1-m distance from the target with inhomogeneity ≤ 30% within the area 0.36 m² (irradiation spot diameter is 0.6 m).Приведены описание и результаты исследований импульсного электронного ускорителя СТРАУС-Р (3,5 МэВ, 60 кА, 60 нс) в двух режимах его работы. В режиме фокусировки электронного пучка ускоритель обеспечивает получение на мишени фокусного пятна диаметром 3…4 мм при максимальной дозе тормозного излучения 27 Р на расстоянии 1 м от выходного фланца. В облучательном режиме максимальная доза тормозного излучения на расстоянии 1 м от мишени по оси ускорителя достигает 36 Р с неоднородностью ≤ 30% на площади 0,36 м² (диаметр пятна облучения 0,6 м).Наведено опис і результати досліджень імпульсного електронного прискорювача СТРАУС-Р (3,5 МеВ, 60 кА, 60 нс) у двох режимах його роботи. У режимі фокусування електронного пучка прискорювач забезпечує одержання на мішені фокусної плями діаметром 3...4 мм при максимальній дозі гальмівного випромінювання 27 Р на відстані 1 м від вихідного фланця. При опроміненні максимальна доза гальмового випромінювання на відстані 1 м від мішені по осі прискорювача досягає 36 Р с неоднорідністю ≤ 30% на площі 0,36 м² (діаметр плями опромінення 0,6 м)

Exact conserved quantities on the cylinder I: conformal case

The nonlinear integral equations describing the spectra of the left and right (continuous) quantum KdV equations on the cylinder are derived from integrable lattice field theories, which turn out to allow the Bethe Ansatz equations of a twisted ``spin -1/2'' chain. A very useful mapping to the more common nonlinear integral equation of the twisted continuous spin $+1/2$ chain is found. The diagonalization of the transfer matrix is performed. The vacua sector is analysed in detail detecting the primary states of the minimal conformal models and giving integral expressions for the eigenvalues of the transfer matrix. Contact with the seminal papers \cite{BLZ, BLZ2} by Bazhanov, Lukyanov and Zamolodchikov is realised. General expressions for the eigenvalues of the infinite-dimensional abelian algebra of local integrals of motion are given and explicitly calculated at the free fermion point.Comment: Journal version: references added and minor corrections performe