The dynamics of and radiation from a copper-wire corona in a megaampere Z-pinch

Evolution of the extreme ultraviolet (XUV) and soft X-ray (SXR) emission in the 50-to 2000-eV photon energy range from a plasma corona formed by loading a relatively thick Cu wire (with an initial diameter of 120 µm) was observed in a Z-pinch discharge with a maximum current of 2 MA and current rise time of 100 ns. A diagnostic complex consisting of a five-channel SXR polychromator, a four-frame X-ray pinhole camera, and a mica crystal spectrograph shows that double-humped emission pulses in the XUV and SXR spectral ranges are generated 70–130 ns after the onset of the discharge current. The total energy of the pulses is 5 kJ, and the maximum power is 60 GW. A part of the observed kiloelectronvolt X-ray emission from three to five spots with diameters of 1–2 mm consists of the Cu K-and L-shell lines.     

Modelling sediment supply to rivers and reservoirs in Eastern Europe during and after the collectivisation period

The present paper reports the results on the occurrence and composition of steady state phytoplankton assemblages in the shallow water bodies of 18 Bulgarian natural wetlands. They all differ in their morphometry, hydrology and trophic state. Steady states were identified according to Sommer & Padisák (1993) when (i) 1, 2 or 3 species of algae contribute more than 80% of total biomass, (ii) their existence or coexistence persists for long enough (more than 1–2 weeks) and (iii) during that period the total biomass does not increase significantly. These situations were rare and were dominated by 7 stress-tolerant, colony-forming and ruderal disturbance-tolerant cyanoprokaryotes (Microcystis aeruginosa, Microcystis wesenbergii, Anabaena spiroides, Anabaenopsis arnoldii, Aphanizomenon flos-aquae, Aphanizomenon gracile and Cylindrospermopsis raciborskii). The equilibrium states had been registered only during hypertrophic conditions in three stressed and frequently disturbed shallow water bodies and were related to the summer – late summer season.     

Laser-generated plasmas at INFN-LNS

Hot plasmas can be generated by fast and intense laser pulses ablating solids placed in vacuum. A Nd:Yag laser operating at the fundamental and second harmonics with 9-ns pulses (maximum energy of 900 mJ) focused on metallic surfaces produces high ablation yields of the order of μg/pulse and dense plasma that expands adiabatically at supersonic velocity along the normal to the target surface. The plasma emits neutral and charged particles. Charge states up to 10+ have been measured in heavy elements ablated with intensities of the order of 10¹⁰ W/cm². The ion temperature of the plasma is evaluated from the ion energy distributions measured with an ion energy analyzer. The electron temperature is measured through Faraday cups placed at the end of long drift tubes by using time-of-flight technique. The neutral temperature is measured with a special mass quadrupole spectrometer placed along the normal to the target surface. The plasma temperature increases with the laser pulse intensity. The ion temperature reaches values of the order of 400 eV, the electron temperature is of the order of 1 keV for hot electrons and 0.1 eV for thermal electrons, and the neutral temperature is of the order of 200 eV. The experimental apparatus, the diagnostic techniques, and the procedures for the plasma temperature characterization will be presented and discussed in detail. Published in Russian in Fizika Plazmy, 2006, Vol. 32, No. 6, pp. 558–564. The text was submitted by the authors in English.     

Flexibility in manufacturing: A survey

This article is an attempt to survey the vast literature on flexibility in manufacturing that has accumulated over the last 10 to 20 years. The survey begins with a brief review of the classical literature on flexibility in economics and organization theory, which provides a background for manufacturing flexibility. Several kinds of flexibilities in manufacturing are then defined carefully along with their purposes, the means to obtain them, and some suggested measurements and valuations. Then we examine the interrelationships among the several flexibilities. Various empirical studies and analytical/optimization models dealing with these flexibilities are reported and discussed. The article concludes with suggestions for some possible future research directions.     

Endocrine alterations that underlie endotoxin-induced disruption of the follicular phase in ewes

Two experiments were conducted to investigate endocrine mechanisms by which the immune/inflammatory stimulus endotoxin disrupts the follicular phase of the estrous cycle of the ewe. In both studies, endotoxin was infused i.v. (300 ng/kg per hour) for 26 h beginning 12 h after withdrawal of progesterone to initiate the follicular phase. Experiment 1 sought to pinpoint which endocrine step or steps in the preovulatory sequence are compromised by endotoxin. In sham-infused controls, estradiol rose progressively from the time of progesterone withdrawal until the LH/FSH surges and estrous behavior, which began approximately 48 h after progesterone withdrawal. Endotoxin interrupted the preovulatory estradiol rise and delayed or blocked the LH/FSH surges and estrus. Experiment 2 tested the hypothesis that endotoxin suppresses the high-frequency LH pulses necessary to stimulate the preovulatory estradiol rise. All 6 controls exhibited high-frequency LH pulses typically associated with the preovulatory estradiol rise. As in the first experiment, endotoxin interrupted the estradiol rise and delayed or blocked the LH/FSH surges and estrus. LH pulse patterns, however, differed among the six endotoxin-treated ewes. Three showed markedly disrupted LH pulses compared to those of controls. The three remaining experimental ewes expressed LH pulses similar to those of controls; yet the estradiol rise and preovulatory LH surge were still disrupted. Our results demonstrate that endotoxin invariably interrupts the preovulatory estradiol rise and delays or blocks the subsequent LH and FSH surges in the ewe. Mechanistically, endotoxin can interfere with the preovulatory sequence of endocrine events via suppression of LH pulsatility, although other processes such as ovarian responsiveness to gonadotropin stimulation appear to be disrupted as well.