332 research outputs found
The character of the name dispute between Macedonia and Greece
The study discusses the character of the name issue between Macedonia and Greece. Launching the conflict energy and open and hidden items of the dispute is of crucial importance for the mediators and politicians involved in its resolution and diplomatic and technical opportunity thereof. This definitely has impact on the parties in their attempts to disclose and control their own emotional
energies involved in the dispute assisting in its rationalisation. It also provides chronology of the conflicting phases through which the dispute is canalised with regard to the latest mediator's proposals for its resolution
The Banking Sector and the Great Depression in Bulgaria, 1924 - 1938: Interlocking and Financial Sector Profitability
The economic narratives of Southeast Europe during the first part of the 20th century are currently being re-written. A story of failed industrialisation and delayed modernisation during the Interwar period has dominated since the pioneering work of Gerschenkron, but not enough aggregate data are available to see this as the only interpretation. In particular, virtually nothing is known about the financial system. This paper has two aims. First, it looks at the banking sector in Bulgaria in 1924- 1938. We provide new data for the 1920s rise and the 1930s decline of the Bulgarian banking sector and we evaluate its potential contribution to Bulgarian economic growth. In the second part, we discuss different explanations for the widespread collapse of commercial banks after the onset of the Great Depression. Relying on a new data set for over 100 Bulgarian commercial banks, we show that traditional explanations for the collapse of European commercial banks in the 1930s (based on the default of risky loans and falling asset prices due to deflation) need to be complemented by the pernicious effects of widespread insider lending in the Bulgarian case. We conclude that insider lending was the single most important factor behind the demise of the private banking system after the onset of the Depression.Bulgarian economic development; Banking and finance; Great Depression; Insider lending
Melatonin, corticosterone, stress and phagocytic activity
ABSTRACT: The present study was conducted to detct the direct reletionships between melatonin and corticosterone under stress condition and possible actions of the two hormones on phagocitic activity of rat peritoneal macrophages. Two experiments were performed. In the first one stress increased the corticosterone plasma concentration to 287+-23 ng/ml while nocturnal melatonin levels were depressed. Clear rise in macrophages capacity to ingest latex beads was noticed when they were incubated with maximum melatonin added (115 pg/ml) and combination of melatonin and corticosterone combinations investigated. The results concerning phagocytic efficiency showed that only significant differences were when phagocytes were received from unstressed rats.
РЕЗЮМЕ: Настоящото изследване бе проведено за да се изяснят взаимоотношенията между нивото на мелатонина и кортикостерона в кръвта на плъхове по време на стрес и влиянието на двата хормона върху фагоцитната активност на макрофаги получени от стресирани плъхове. За целта бяха проведени два експеримента. При първия нивото на кортикостерона в кръвта по време на стрес достигна 287 +- 23 ng/ml, докато нивото на мелатонина през нощта бе подтиснато.
Повишение на фагоцитната активност бе отбелязана след добавяне на максималното тестирано количество мелатонин (115 pg/ml) или комбинации от мелатонин и кортикостерон. Резултатите отнасящи се до фагоцитната активност показват, че единствено статистически достоверно различие се получава когато фагоцитите бяха получавани от несъпресирани плъхове
Spectro-temporal shaping of seeded free-electron laser pulses
We demonstrate the ability to control and shape the spectro-temporal content
of extreme-ultraviolet (XUV) pulses produced by a seeded free-electron laser
(FEL). The control over the spectro-temporal properties of XUV light was
achieved by precisely manipulating the linear frequency chirp of the seed
laser. Our results agree with existing theory, which allows retrieving the
temporal properties (amplitude and phase) of the FEL pulse from measurements of
the spectra as a function of the FEL operating parameters. Furthermore, we show
the first direct evidence of the full temporal coherence of FEL light and
generate Fourier limited pulses by fine-tuning the FEL temporal phase. The
possibility to tailor the spectro-temporal content of intense short-wavelength
pulses represents the first step towards efficient nonlinear optics in the XUV
to X-ray spectral region and will enable precise manipulation of core-electron
excitations using the methods of coherent quantum control.Comment: 5 pages, 3 figure
Single-shot fluctuations in waveguided high-harmonic generation
For exploring the application potential of coherent soft x-ray (SXR) and
extreme ultraviolet radiation (XUV) provided by high-harmonic generation, it is
important to characterize the central output parameters. Of specific importance
are pulse-to-pulse (shot-to-shot) fluctuations of the high-harmonic output
energy, fluctuations of the direction of the emission (pointing instabilities),
and fluctuations of the beam divergence and shape that reduce the spatial
coherence. We present the first single-shot measurements of waveguided
high-harmonic generation in a waveguided (capillary-based) geometry. Using a
capillary waveguide filled with Argon gas as the nonlinear medium, we provide
the first characterization of shot-to-shot fluctuations of the pulse energy, of
the divergence and of the beam pointing. We record the strength of these
fluctuations vs. two basic input parameters, which are the drive laser pulse
energy and the gas pressure in the capillary waveguide. In correlation
measurements between single-shot drive laser beam profiles and single-shot
high-harmonic beam profiles we prove the absence of drive laser
beam-pointing-induced fluctuations in the high-harmonic output. We attribute
the main source of high-harmonic fluctuations to ionization-induced nonlinear
mode mixing during propagation of the drive laser pulse inside the capillary
waveguide
The seed laser system of the FERMI free-electron laser: design, performance and near future upgrades
Abstract
An important trend in extreme ultraviolet and soft X-ray free-electron laser (FEL) development in recent years has been the use of seeding by an external laser, aimed to improve the coherence and stability of the generated pulses. The high-gain harmonic generation seeding technique was first implemented at FERMI and provided FEL radiation with high coherence as well as intensity and wavelength stability comparable to table-top ultrafast lasers. At FERMI, the seed laser has another very important function: it is the source of external laser pulses used in pump–probe experiments allowing one to achieve a record-low timing jitter. This paper describes the design, performance and operational modes of the FERMI seed laser in both single- and double-cascade schemes. In addition, the planned upgrade of the system to meet the challenges of the upgrade to echo-enabled harmonic generation mode is presented
Seeded x-ray free-electron laser generating radiation with laser statistical properties
The invention of optical lasers led to a revolution in the field of optics
and even to the creation of completely new fields of research such as quantum
optics. The reason was their unique statistical and coherence properties. The
newly emerging, short-wavelength free-electron lasers (FELs) are sources of
very bright coherent extreme-ultraviolet (XUV) and x-ray radiation with pulse
durations on the order of femtoseconds, and are presently considered to be
laser sources at these energies. Most existing FELs are highly spatially
coherent but in spite of their name, they behave statistically as chaotic
sources. Here, we demonstrate experimentally, by combining Hanbury Brown and
Twiss (HBT) interferometry with spectral measurements that the seeded XUV FERMI
FEL-2 source does indeed behave statistically as a laser. The first steps have
been taken towards exploiting the first-order coherence of FELs, and the
present work opens the way to quantum optics experiments that strongly rely on
high-order statistical properties of the radiation.Comment: 24 pages, 10 figures, 37 reference
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