3,252 research outputs found
A Study of 2008-2009 Mean Scheduled Launch Days as a Key Factor for Planning Future Commercial Scheduling and Resource Allocations at Cape Canaveral Spaceport
This study encompassed initial, rescheduled, and actual launch dates at Cape Canaveral Spaceport where actual launches occurred in the years 2008 and 2009. Each mission launch date was calculated within the context of the mean number of days within each mission launch timeline, using descriptive statistical methodology. The research results illustrate the iterative scheduling associated to the Cape Canaveral Spaceport. The calculated mean times provide a preliminary glimpse of key factors to be considered by spaceport operations teams, launch providers, and customers at Cape Canaveral Spaceport. These factors will be useful to predict resource allocations and forecast commercial operational capacity, to meet demand for launch pads, launch vehicle and payload facilities, scheduling operations, launch control center crew teams, and ground stations
Ökologischer Anbau von Körner- und Grünfuttererbsen im Trockengebiet Österreichs – Ertragsleistung und Vorfruchtwirkung
Die Erbse gilt als die wichtigste Körnerleguminose im Ökologischen Landbau, sowohl in ihrer Funktion als Leguminose zur Versorgung des Betriebes mit Stickstoff, als auch für die Futterproduktion (Geflügel und Schweine). Unter der Annahme einer richtigen Stellung in der Fruchtfolge, gelten der Ertrag, die N2-Fixierungsleistung sowie die Konkurrenzkraft gegenüber Beikraut als die wichtigsten Merkmale in der Entscheidungsfindung der Sortenauswahl. Für die Tierernährung ist die Proteinqualität, im engeren Sinn der Gehalt an essentiellen Aminosäuren entscheidend. Ziel dieses Projektes ist die Untersuchung verschiedener Erbsensorten bzw. -gemenge sowie von verschiedenen Hauptfrucht (Erbse)-Zwischenfrucht (legum/nicht legum)-Kombinationen im Hinblick auf ihre Biomassebildung, N2-Fixierleistung, Konkurrenzkraft gegenüber Beikräutern, Futtermittelparameter und Vorfruchtwert
Plant biomass nitrogen and effects on the risk of nitrate leaching of intercrops under organic farming in Eastern Austria
Data on the potential of intercrops to reduce soil nitrate contents, on their N accumulation and biological nitrogen fixation (BNF) are lacking for organic farming in the dry, pannonic region of Eastern Austria. The effect of legumes, non-legumes, and legumes + non-legumes used as intercrops on inorganic soil nitrogen, crop yield and biomass N, and BNF were tested in comparison to bare fallow. Non-legumes and legumes + non-legumes were more efficient than legumes in reducing inorganic soil N contents in autumn and nitrate contents in soil solution from the subsoil in winter. This reduction in inorganic soil N did not last until March of the following year due to an N mineralisation from the mulch. The legume + non-legume mixture contained a larger amount of crop N than both legumes and non-legumes. This was due to the combined effect of soil-N uptake by the non-legumes and BNF by the legumes in the mixture
Chromosomal anchoring of linkage groups and identification of wing size QTL using markers and FISH probes derived from microdissected chromosomes in Nasonia(Pteromalidae : Hymenoptera)
Nasonia vitripennis is a small parasitic hymenopteran with a 50-year history of genetic work including linkage mapping with mutant and molecular markers. For the first time we are now able to anchor linkage groups to specific chromosomes. Two linkage maps based on a hybrid cross (N. vitripennis x N. longicornis) were constructed using STS, RAPID and microsatellite markers, where 17 of the linked STS markers were developed from single microdissected banded chromosomes. Based on these microdissections we anchored all linkage groups to the five chromosomes of N. vitripennis. We also verified the chromosomal specificity of the microdissection through in situ hybridization and linkage analyses. This information and technique will allow us in the future to locate genes or QTL detected in different mapping populations efficiently and fast on homologous chromosomes or even chromosomal regions. To test this approach we asked whether QTL responsible for the wing size in two different hybrid crosses (N. vitripennis x N. longicornis and N. vitripennis x N. giraulti) map to the same location. One QTL with a major effect was found to map to the centromere region of chromosome 3 in both crosses. This could indicate that indeed the same gene/s is involved in the reduction of wing in N. vitripennis and N. longicornis. Copyright (C) 2003 S. Karger AG, Basel
Ertrag, N2-Fixierungsleistung und Wassernutzungseffizienz von Futterleguminosen in einem Ökologischen Anbausystem
In Anbausystemen des Ökologischen Landbaus ist die Stickstoffzufuhr über die Symbiose aus Wurzelknöllchenbakterien (Rhizobien) und Leguminosen (Familie Fabaceae) die wichtigste Stickstoffquelle. Unter den klimatischen Bedingungen der pannonischen Region im Osten Österreichs kann sowohl das Wachstum und die Entwicklung der Leguminosen, als auch die Stickstoffixierleistung durch Trockenperioden limitiert werden. Der Beitrag der Leguminosen zur Stickstoffversorgung der Fruchtfolgeglieder ist neben den standortspezifischen Faktoren u.a. von der Leguminosenart, dem Gemengepartner (Gras), und der Anbau- und Nutzungsform (Anbaudauer, Schnittnutzung oder Gründüngung) abhängig. Ziel des Forschungsprojektes ist die Optimierung des Futterleguminosenanbaus im pannonischen Klimaraum Ostösterreichs unter produktionstechnischen und ökologischen Gesichtspunkten. Dies soll durch einen Vergleich verschiedener Leguminosen-Gräsergemenge und Nutzungsverfahren unter dem Einfluß des zur Verfügung stehenden Wasserangebotes erreicht werden
Constraints on the Compact Object Mass in the Eclipsing HMXB XMMU J013236.7+303228 in M33
We present optical spectroscopic measurements of the eclipsing High Mass
X-ray Binary XMMU J013236.7+303228 in M33. Based on spectra taken at multiple
epochs of the 1.73d binary orbital period we determine physical as well as
orbital parameters for the donor star. We find the donor to be a B1.5IV
sub-giant with effective temperature T=22,000-23,000 K. From the luminosity,
temperature and known distance to M33 we derive a radius of R = 8.9 \pm 0.5
R_sun. From the radial--velocity measurements, we determine a velocity
semi-amplitude of K_opt = 63 \pm 12 km/sec. Using the physical properties of
the B-star determined from the optical spectrum, we estimate the star's mass to
be M_opt = 11 \pm 1 M_sun. Based on the X-ray spectrum, the compact companion
is likely a neutron star, although no pulsations have yet been detected. Using
the spectroscopically derived B-star mass we find the neutron star companion
mass to be M_X = 2.0 \pm 0.4 M_sun, consistent with the neutron star mass in
the HMXB Vela X-1, but heavier than the canonical value of 1.4 M_sun found for
many millisecond pulsars. We attempt to use as an additional constraint that
the B star radius inferred from temperature, flux, and distance, should equate
the Roche radius, since the system accretes by Roche lobe overflow. This leads
to substantially larger masses, but from trying to apply the technique to known
systems, we find that the masses are consistently overestimated. Attempting to
account for that in our uncertainties, we derive M_X = 2.2^{+0.8}_{-0.6} M_sun
and M_opt =13 \pm 4 M_sun. We conclude that precise constraints require
detailed modeling of the shape of the Roche surface.Comment: 11 pages emulateapj, 9 figures, ApJ accepte
Ertragsentwicklung von Erbsen sowie Sommergerste in Reinsaat und in Mischung mit Leindotter oder Koriander im Ökologischen Landbau
Mischkulturen können unterschiedliche Wachstumsbedingungen besser ausschöpfen als Monokulturen. Im Gemenge mit Leguminosen können Nicht-Leguminosen überschüssigen Stickstoff aus der Bodenlösung aufnehmen. Ein ökonomischer Zusatzertrag wird bei einer Beimengung von Leindotter zu Erbsen oder Sommergerste diskutiert. Erbsenreinsaaten erreichten im Vergleich zu beiden Leindotter-Varianten gesichert höhere Erträge; Erbsen mit resp. ohne Koriander unterschieden sich nicht. Sommergerste – Reinsaaten waren bezüglich dem Ertrag den Mischungen mit Leindotter überlegen; Koriander wurde von der Sommergerste vollständig unterdrückt. Abschließend kann festgehalten werden, dass unter limitierenden Niederschlägen im pannonischen Klimaraum dem Mischkulturanbau enge Grenzen gesetzt sind
J004457+4123 (Sharov 21): not a remarkable nova in M31 but a background quasar with a spectacular UV flare
We announce the discovery of a quasar behind the disk of M31, which was
previously classified as a remarkable nova in our neighbour galaxy. The paper
is primarily aimed at the outburst of J004457+4123 (Sharov 21), with the first
part focussed on the optical spectroscopy and the improvement in the
photometric database. Both the optical spectrum and the broad band spectral
energy distribution of Sharov 21 are shown to be very similar to that of
normal, radio-quiet type 1 quasars. We present photometric data covering more
than a century and resulting in a long-term light curve that is densely sampled
over the past five decades. The variability of the quasar is characterized by a
ground state with typical fluctuation amplitudes of ~0.2 mag around B~20.5,
superimposed by a singular flare of ~2 yr duration (observer frame) with the
maximum at 1992.81 where the UV flux has increased by a factor of ~20. The
total energy in the flare is at least three orders of magnitudes higher than
the radiated energy of the most luminous supernovae, provided that it comes
from an intrinsic process and the energy is radiated isotropically. The profile
of the flare light curve appears to be in agreement with the standard
predictions for a stellar tidal disruption event where a ~10 M_sun giant star
was shredded in the tidal field of a ~2...5 10^8 M_sun black hole. The short
fallback time derived from the light curve requires an ultra-close encounter
where the pericentre of the stellar orbit is deep within the tidal disruption
radius. Gravitational microlensing provides an alternative explanation, though
the probability of such a high amplification event is very low.Comment: Accepted for publication in Astronomy and Astrophysics, 14 pages, 11
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