511 research outputs found
The Influence of Heterogeneous Information on Software Engineering
The deployment of DHCP has evaluated Smalltalk, and current trends suggest that the robust unification of web browsers and kernels will soon emerge. In this paper, authors disprove the development of consistent hashing, demonstrates the confusing importance of hardware and architecture [1]. SMOKE, our new system for unstable epistemologies, is the solution to all of these challenges
Flight Measurements with the Douglas D-558-II (buaero No. 37974) Research Airplane : Static Longitudinal Stability and Control Characteristics at Mach Numbers up to 0.87
STABCAR: A program for finding characteristic root systems having transcendental stability matrices
STABCAR can be used to determine the characteristic roots of flexible, actively controlled aircraft, including the effects of unsteady aerodynamics. A modal formulation and a transfer-matrix representation of the control system are employed. Operable in either a batch or an interactive mode, STABCAR can provide graphical or tabular output of the variation of the roots with velocity, density, altitude, dynamic pressure or feedback gains. Herein the mathematical model, program structure, input requirements, output capabilities, and a series of sample cases are detailed. STABCAR was written for use on CDC CYBER 175 equipment; modification would be required for operation on other machines
Phase vortices from a Young's three-pinhole interferometer
An analysis is presented of the phase vortices generated in the far field, by
an arbitrary arrangement of three monochromatic point sources of complex
spherical waves. In contrast with the case of three interfering plane waves, in
which an infinitely-extended vortex lattice is generated, the spherical sources
generate a finite number of phase vortices. Analytical expressions for the
vortex core locations are developed and shown to have a convenient
representation in a discrete parameter space. Our analysis may be mapped onto
the case of a coherently-illuminated Young's interferometer, in which the
screen is punctured by three rather than two pinholes.Comment: 10 pages, 8 figures, REVTeX4, Submitted to Phys. Rev.
4U2206+54 - an Unusual High Mass X-ray Binary with a 9.6 Day Orbital Period but No Strong Pulsations
Rossi X-ray Timing Explorer All-Sky Monitor observations of the X-ray source
4U2206+54, previously proposed to be a Be star system, show the X-ray flux to
be modulated with a period of approximately 9.6 days. If the modulation is due
to orbital variability then this would be one of the shortest orbital periods
known for a Be star X-ray source. However, the X-ray luminosity is relatively
modest whereas a high luminosity would be predicted if the system contains a
neutron star accreting from the denser inner regions of a Be star envelope.
Although a 392s pulse period was previously reported from EXOSAT observations,
a reexamination of the EXOSAT light curves does not show this or any other
periodicity. An analysis of archival RXTE Proportional Counter Array
observations also fails to show any X-ray pulsations. We consider possible
models that may explain the properties of this source including a neutron star
with accretion halted at the magnetosphere and an accreting white dwarf.Comment: Accepted for publication in the Astrophysical Journa
Evidence for a very slow X-ray pulsar in 2S0114+650 from RXTE All-Sky Monitor Observations
Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM) observations of the
X-ray binary 2S0114+650 show modulations at periods close to both the optically
derived orbital period (11.591 days) and proposed pulse period (~ 2.7 hr). The
pulse period shows frequency and intensity variability during the more than 2
years of ASM observations analyzed. The pulse properties are consistent with
this arising from accretion onto a rotating neutron star and this would be the
slowest such period known. The shape of the orbital light curve shows
modulation over the course of the entire orbit and a comparison is made with
the orbital light curve of Vela X-1. However, the expected phase of eclipse,
based on an extrapolation of the optical ephemeris, does not correspond with
the observed orbital minimum. The orbital period derived from the ASM light
curve is also slightly longer than the optical period.Comment: To be published in the Astrophysical Journal, 1999, volume 511. 9
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Automated Control Systems and Methods for Underground Crop Harvesters
Methods and devices for automated adjustment of a digging implement during harvest of underground crops are described. Utilizing the devices, a digging implement, e.g., a blade, can be located and maintained at a desired depth as a harvester travels across a field. During use, the digging implement depth controls can be varied as the harvester travels within a single field under different operating conditions, e.g., different soil friability, consistency, etc., thereby preventing crop loss and improving crop yield
Impact mass flow sensor for monitoring peanut harvest yields
Yield monitoring systems for harvesting machines and methods that can provide yield monitoring of crops are described. Machines include those that pneumatically convey crop through the machine such as peanut harvesting machines. The yield monitoring system includes a force sensor that can be located in conjunction with a duct of the harvesting machine such that impact of the crop materials on an impact plate within the duct will be registered by the force sensor. This registration can be used to determine a mass flow rate for the crop, which can be correlated to yield of the crop. The systems can include additional components such as optical monitors, moisture sensors, and pressure sensors
Alcoholism and recovery: A case study of a former professional footballer
What little we know about alcoholism amongst professional footballers comes largely from the media (often tabloid newspapers) and published autobiographies and biographies of high profile stars. The coverage often focuses on deviant behaviour when drunk, such as driving under the influence, marital infidelity, violence, and breaking team rules. There is little or no published research which seeks to understand better what it is like to suffer from alcoholism from the perspective of the player-addicts themselves. In this paper I present a case study of British footballer who had a brief professional career and is in recovery from alcoholism. His subjective experience of alcoholism provides valuable insights into the underlying triggers and/or causes of the illness; its destructive nature; the link between the individual’s addiction and his social circumstances (including football); and his recovery
Trends in Chondrichthyan Research: An Analysis of Three Decades of Conference Abstracts
Given the conservation status and ecological, cultural, and commercial importance of chondrichthyan fishes, it is valuable to evaluate the extent to which research attention is spread across taxa and geographic locations and to assess the degree to which scientific research is appropriately addressing the challenges they face. Here we review trends in research effort over three decades (1985–2016) through content analysis of every abstract (n = 2,701) presented at the annual conference of the American Elasmobranch Society (AES), the oldest and largest professional society focused on the scientific study and management of these fishes. The most common research areas of AES abstracts were reproductive biology, movement/telemetry, age and growth, population genetics, and diet/feeding ecology, with different areas of focus for different study species or families. The most commonly studied species were large and charismatic (e.g., White Shark, Carcharodon carcharias), easily accessible to long-term established field research programs (e.g., Lemon Shark, Negaprion brevirostris, and Sandbar Shark, Carcharhinus plumbeus), or easily kept in aquaria for lab-based research (e.g., Bonnethead Shark, Sphyrna tiburo). Nearly 90% of all described chondrichthyan species have never been mentioned in an AES abstract, including some of the most threatened species in the Americas. The proportion of female* first authors has increased over time, though many current female* Society members are graduate students. Nearly half of all research presented at AES occurred in the waters of the United States rather than in the waters of developing nations where there are more threatened species and few resources for research or management. Presentations based on research areas such as paleontology and aquarium-based research have declined in frequency over time, and identified research priorities such as social science and interdisciplinary research are poorly represented. Possible research gaps and future research priorities for the study of chondrichthyan fishes are also discussed
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