A preliminary determination of normal accelerations on racing airplanes

Rules and methods for insuring safe structural strength of racing airplanes used in the major air meets in this country have recently been considered. Acceleration records made in racing airplanes during actual air races were therefore considered desirable, and the NACA undertook the measurement of acceleration of loads on airplanes during all conditions of flight. Accelerations were measured on four airplanes at the Miami All-American Races in January 1934 and January 1935. The airplanes were representative of the fastest limited and unlimited displacement racing airplanes in current use in this country. Records during two races, or flights, on the race course were obtained with each airplane. The maximum normal acceleration recorded was 6.2g and the minimum was -1.2g

Knowledge management challenges in corporate venturing and technological capability building through radical innovations

radical innovation, technological capability, corporate venturing, knowledge management

Re-establishment programme for Acipenser sturio L., 1758: The German approach

Acipenser sturio L., 1758 was a prevalent species of the fish communities in all major German rivers' waters until the end of the 19th century. Since then, the population sizes decreased rapidly due to overfishing, pollution, and hydro-construction, and the last remaining population was observed in the Eider River until the 1960s. Recently, specimens have been observed in German waters only rarely. Until the end of the 1980s, neither politicians nor ecologists considered reestablishment measures feasible in Germany. In 1994, joint activities of scientists and aquaculturists led to the foundation of the Society to Save the Sturgeon (A. sturio L.), aimed at co-ordinating the A. sturio restoration measures in Germany. A federal programme was initiated, supporting in part the various subprojects dealing with this matter. Under a scientific co-operation agreement with France's Cemagref, the Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin received, in May 1996, juvenile A. sturio for the establishment of a broodstock, as an ex-situ measure to save the species. The IGB also carries out research on various aspects of A. sturio biology. Together with the Cemagref, genetic analyses of remaining populations and specimens are conducted as a basis for a long-term breeding programme. The broodstock development is carried out in co-operation with the Research Institute for Agriculture and Fisheries of Mecklenburg-Vorpommern, where experiments with model species are performed within the framework of the programme. Evaluation measures for the restoration of A. sturio in the Odra and Elbe Rivers are carried out by the Society in collaboration with the Institute for Inland Fisheries of Poland. Additionally morphometric and meristic studies are conducted at the University of Rostock to characterise the species. The evaluation of the remaining populations in other European regions, in particular Romania and Georgia, is considered an important element for its future development. International co-operation in general is an essential aspect of future attempts to save the species.Acipenser sturio L., 1758 fue una especie frecuente en las comunidades de peces en las aguas de todos los grandes ríos alemanes hasta finales del siglo XIX. Desde entonces, los tamaños de las poblaciones disminuyeron rápidamente debido a sobrepesca, contaminación y obras hidráulicas, y la última población superviviente fue observada en el río Eider hasta la década de los sesenta. Recientemente, sólo raramente han sido observados ejemplares en aguas alemanas. Hasta finales de los ochenta, ni políticos ni ecologistas consideraron posibles las medidas de recuperación en Alemania. En 1994 las actividades conjuntas de científicos y acuicultores llevaron a la fundación de la Sociedad para Salvar el Esturión (A. sturio L.), aspirante a coordinar las medidas de recuperación de A. sturio en ese país. Se inició un programa federal, financiando en parte distintos subproyectos. Bajo un acuerdo científico de cooperación con Cemagref de Francia, el Instituto de Ecología Dulceacuícola y Pescas Interiores (IGB) de Berlín recibió, en mayo de 1996, juveniles de A. sturio para el establecimiento de un stock de cría, como una medida ex-situ para salvar a la especie. El IGB también investiga sobre varios aspectos de la biología de A. sturio; colabora con Cemagref en la realización de análisis genéticos de las poblaciones y de ejemplares remanentes como base para un programa de cría a largo plazo. El desarrollo del stock de cría se lleva a cabo en cooperación con el Instituto de Investigación para Agricultura y Pesca de Mecklenburg-Vorpommern, donde se realizan estudios experimentales con especies modelo dentro del marco del programa. Las medidas de evaluación para la recuperación de A. sturio en los ríos Oder y Elba se establecen por la Sociedad para Salvar el Esturión en colaboración con el Instituto de Pescas Interiores de Polonia. Adicionalmente se llevan a cabo estudios morfométricos y merísticos en la Universidad de Rostock para caracterizar a la especie. La evaluación de las poblaciones remanentes en otras regiones europeas, particularmente en Rumania y Georgia, se considera un elemento importante para su futuro desarrollo. La cooperación internacional en general es un aspecto esencial de los intentos futuros para salvar a la especie.Instituto Español de Oceanografí

On the structure of framed vertex operator algebras and their pointwise frame stabilizers

In this paper, we study the structure of a general framed vertex operator algebra. We show that the structure codes (C,D) of a framed VOA V satisfy certain duality conditions. As a consequence, we prove that every framed VOA is a simple current extension of the associated binary code VOA V_C. This result would give a prospect on the classification of framed vertex operator algebras. In addition, the pointwise frame stabilizer of V is studied. We completely determine all automorphisms in this pointwise stabilizer, which are of order 1, 2 or 4. The 4A-twisted sector and the 4A-twisted orbifold theory of the famous Moonshine VOA are also constructed explicitly. We verify that the top module of this twisted sector is of dimension 1 and of weight 3/4 and the VOA obtained by 4A-twisted orbifold construction of the moonshine VOA is isomorphic to the moonshine VOA itself.Comment: Version 3: 59 pages. Corrected version. 54 pages on my LaTeX system version 2: We add Theorem 5.16 in which we give a necessary and sufficient condtion for a code to be a structure code of a holomorphic framed VOA. "hyperref" style is also introduce

No detectable aerobic methane efflux from plant material, nor from adsorption/desorption processes

In early 2006, Keppler et al. (Nature, 439:187–191) reported a novel finding that plant leaves, and even simple organic materials, can release methane under aerobic conditions. We investigated here whether the reported methane release might simply arise from methane desorption from sample surfaces after prior exposure to higher methane concentrations. We exposed standard cellulose filter papers (i.e. organic material with a high surface area) to atmospheric methane concentration and then transferred them to a low-methane atmosphere. Our results suggest that any desorption flux was extremely small (−0.0001±0.0019 ngCH<sub>4</sub> kgDW<sup>−1</sup> s<sup>−1</sup>) and would play no quantitatively significant role in modifying any measured methane fluxes. <br> <br> We also incubated fresh detached leaves of several species and intact <i>Zea mays</i> seedlings under aerobic and low-light conditions. After correcting for a small measured methane influx into empty chambers, measured rates of methane emission by plant materials were zero or, at most, very small, ranging from −0.25±1.1 ngCH<sub>4</sub> kgDW<sup>−1</sup> s<sup>−1</sup> for <i>Zea mays</i> seedlings to 0.10±0.08 ngCH<sub>4</sub> kgDW<sup>−1</sup> s<sup>−1</sup> for a mixture of freshly detached grasses. These rates were much smaller than the rates originally reported by Keppler et al. (2006)

Restoration of Acipenser sturio L., 1758 in Germany: Growth characteristics of juvenile fish reared under experimental indoor conditions

The survival of the highly endangered Acipenser sturio L., 1758 depends nearly exclusively upon the establishment of captive broodstocks. Such measures were initiated in Germany in 1996, due to a transfer of 40 artificially reproduced individuals from France under a co-operation agreement. We report the results of rearing these fish for a period of 3 years under freshwater conditions. During the first year the fish being exclusively fed frozen chironomid larvae (N = 40) grew from a median of 27 cm (with range of 23-31 cm), averaging 71 g (42-112 g), to 43 cm (38-51 cm) and 280 g (168-505 g) at a mean temperature of 20 °C (13-27 °C). Following their transfer to larger tanks (approx. 5 m³) at a mean temperature of 21 °C (17-24 °C), the fish (N = 27) reached a length of 68 cm (56-76 cm), averaging 1 281 g (512-2 097 g) at the end of the second year. Decreasing growth and increasing food conversion rates (FCR) during the first four months of the third year made us change the food composition (addition of large chironomids, krill and small marine fish). An increase in growth and a decrease in FCR was observed over the next four months resulting in a median length of 76 cm (58-89 cm), with a weight of 1 827 g (855-3 462 g) at the end of the third year (N = 27). Our fish showed rather large differences in growth, with some individuals reaching the maximum weight gain observed in wild fish, thus indicating the potential to optimise results by future testing involving additional natural food items in order to develop a formulated diet to stimulate early sexual maturation.La supervivencia del altamente amenazado Acipenser sturio L., 1758 depende casi exclusivamente del establecimiento de stocks de cría en cautividad. Tales medidas fueron iniciadas en Alemania en 1996, gracias a la transferencia desde Francia bajo un convenio de cooperación de 40 individuos reproducidos artificialmente. Presentamos los resultados de la cría de estos peces por un periodo de tres años en condiciones dulceacuícolas. Durante el primer año los peces (N = 40) siendo alimentados exclusivamente con larvas congeladas de quironómidos crecieron desde una media de 27 cm (con rango de 23-31 cm), promediando 71 g (42-112 g), a 43 cm (38-51) y 280 g (168-505 g) a una temperatura media de 20 °C (13-27 °C). A continuación de su traslado a tanques más grandes (de aproximadamente 5 m³) a una temperatura media de 21 °C (17-24 °C), los peces (N = 27) alcanzaron una longitud de 68 cm (56-76 cm), promediando 1 281 g (521-2 097 g) al final del segundo año. La disminución del crecimiento y el incremento de las tasas de con versión de alimento (TCA) durante los primeros cuatro meses del tercer año nos hicieron cambiar la composición del alimento (adición de quironómidos de gran tamaño, krill y pequeños peces marinos). Un incremento en el crecimiento y una disminución de las TCA fueron observados durante los cuatro meses siguientes resultando una longitud media de 76 cm (58-89 cm), con un peso de 1 827 g (855-3 462 g) al final del tercer año (N = 27). Nuestros peces mostraron numerosas diferencias en crecimiento, con algunos individuos alcanzando la mayor ganancia en peso observada en peces silvestres, indicando así el potencial para optimizar resultados por futuras pruebas que incluyan alimentos naturales adicionales en orden a evaluar una dieta formulada para estimular la maduración sexual temprana.Instituto Español de Oceanografí

Ergosterol Concentration of Several Different Saccharomyces cerevisiae Yeast Strains

Differences in the formation of ergosterol in yeast cells have been found amongst several wine yeast strains used in South Africa. A higher ergosterol content is generally accompanied by a faster fermentation rate and results in a shortening of fermentation time. A high ergosterol concentration in the cell is not a prerequisite for maximal cell formation, but probably affects the metabolic activity of the cell. Aeration of the must during the yeast proliferation stage, brought about marked increases in ergosterol concentrations

The drag characteristics of several airships determined by deceleration tests

This report presents the results of deceleration tests conducted for the purpose of determining the drag characteristics of six airships. The tests were made with airships of various shapes and sizes belonging to the Army, the Navy, and the Goodyear-Zeppelin Corporation. Drag coefficients for the following airships are shown: Army TC-6, TC-10, and TE-2; Navy Los Angeles and ZMC-2; Goodyear Puritan. The coefficients vary from about 0.045 for the small blunt airships to 0.023 for the relatively large slender Los Angeles. This variation may be due to a combination of effects, but the most important of these is probably the effect of length-diameter ratio

Further measurements of normal accelerations on racing airplanes

The work of collecting acceleration data for racing airplanes during races, started in January 1934, has been continued by obtaining similar data in the airplanes winning first and second places in the 1935 Thompson Trophy Race. Records were taken in the Howard Racer "Mr. Mulligan" and in the Wittman D-12 Racer. The maximum positive accelerations were generally smaller than those recorded in other airplanes during earlier races; the maximum in the Howard Racer was 2.8 g, and one value of 4.25 g was obtained in the Wittman Racer. Minimum values were as low as -0.55 g in the Howard Racer and 0.3 g in the Wittman Racer

Maneuverability Investigation of an O3U-1 Observation Airplane

This report presents the results of maneuverability tests of an O3U-1 observation airplane. This investigation is the third in a series of similar investigations requested by the Bureau of Aeronautics (Navy) for the purpose of comparing the maneuverability of different airplane types and to provide quantitative data for use in establishing a criterion or method for rating the maneuverability of an airplane. The two former investigations were conducted with the fighter types designated F6C-3 and F6C-4 and have been reported previously. Measurement of the air speed, the angular velocity, the linear acceleration, and positions of the controls were made during abrupt single-control maneuvers with three stop positions for each control, during steady horizontal turns for the determination of minimum radius, and during 180 degree turns by various methods. Flight-path coordinates in two dimensions were determined for the 180 degree turns by means of a special camera obscura designed for the previous investigation of the F6C-4 airplane. All maneuvers were performed at an altitude of approximately 3,000 feet