Perturbing forces in the lunar gravitational potential, part 3 Final report

Spherical harmonics for evaluating perturbing forces on lunar satellite due to nonsymmetric mass distribution of moo

RTCC requirements for mission G - Landing site determination using onboard observations, part 2 Final report

Computer programs for evaluation of telemetered rendezvous radar tracking data of orbiting command module and lunar module landing site determinatio

A Multiscale Investigation of Habitat Use and Within-river Distribution of Sympatric Sand Darter Species

The western sand darter Ammocrypta clara, and eastern sand darter Ammocrypta pellucida are sand-dwelling fishes of conservation concern. Past research has emphasized the importance of studying individual populations of conservation concern, while recent research has revealed the importance of incorporating landscape scale processes that structure habitat mosaics and local populations. We examined habitat use and distributions of western and eastern sand darters in the lower Elk River of West Virginia. At the sandbar habitat use scale, western sand darters were detected in sandbars with greater area, higher proportions of coarse grain sand and faster bottom current velocity, while the eastern sand darter used a wider range of sandbar habitats. The landscape scale analysis revealed that contributing drainage area was an important predictor for both species, while sinuosity, which presumably represents valley type also contributed to the western sand darter’s habitat suitability. Sandbar quality (area, grain size, and velocity) and fluvial geomorphic variables (drainage area and valley type) are likely key driving factors structuring sand darter distributions in the Elk River. This multiscale study of within-river species distribution and habitat use is unique, given that only a few sympatric populations are known of western and eastern sand darters

Letter from A. P. Austin to John Muir, 1904 Dec 19.

National Geographic SocietyOFFICE OF THE SECRETARYHubbard Memorial Hall,Washington, D. C., Dec. 19, 1904.prof. John Muir,Martinez,California.Dear Sir:-I have the honor to inform you that you have been designated as a delegate from the National Geographic Society to the American Forest Congress which is to assemble in Washington, D. C., January 2, 1905, continuing its meetings to January 6.The full list of the delegates from this society is as follows:E. L. Berthond, C. E., Box 45, Golden, Colorado,Wm. P. Blake, University of Arizona, Tucson, Arizona,Dr. J. C. Branner, Standford University, California,Prof. W.N. Brewer, 418 orange St., N. Haven Conn.,Dr. W. B. Clark, John Hopkins University, Balto., Md.,Prof. J. A. Holmes, Univ. of N. C., Chapel Hill, N. C.,D. N. Riordan, 404 Bradbury, Bldg., Los Angeles, Cal.,Prof. I. C. Russell, Univ. of Michigan, Ann Arbor, Mich.,Prof. C.S. Sargeant, Harvard University, Canbridge, Mass.,Prof. John Muir.The purpose of this meeting and the general outline of its work is shown by the enclosed publication. Trusting that you will find it agreeable to represent this society in case you are able to attend this important meeting, I am, Yours very truly, [illegible] Secretary. 0348

Time-resolved measurement of single pulse femtosecond laser-induced periodic surface structure formation

Time-resolved diffraction microscopy technique has been used to observe the formation of laser-induced periodic surface structures (LIPSS) from the interaction of a single femtosecond laser pulse (pump) with a nano-scale groove mechanically formed on a single-crystal Cu substrate. The interaction dynamics (0-1200 ps) was captured by diffracting a time-delayed, frequency-doubled pulse from nascent LIPSS formation induced by the pump with an infinity-conjugate microscopy setup. The LIPSS ripples are observed to form sequentially outward from the groove edge, with the first one forming after 50 ps. A 1-D analytical model of electron heating and surface plasmon polariton (SPP) excitation induced by the interaction of incoming laser pulse with the groove edge qualitatively explains the time-evloution of LIPSS formation.Comment: 4 pages, 5 figure

Vacuum Photon Splitting in Lorentz-Violating Quantum Electrodynamics

Radiative corrections arising from Lorentz violation in the fermion sector induce a nonzero amplitude for vacuum photon splitting. At one loop, the on-shell amplitude acquires both CPT-even and CPT-odd contributions forbidden in conventional electrodynamics.Comment: 4 pages, minor wording changes, references added, accepted in Physical Review Letter

Can trained monkeys design flight controllers for hypersonic vehicles?

The supersonic combustion ramjet is an as yet unproven propulsion system for hypersonic flight. Provided it can be developed into a practical vehicle, the ultimate success of sustained hypersonic flight will depend on configuring a robust and stable airframe-propulsion-control combination. To design the longitudinal flight controller for this inherently unstable vehicle we have applied a genetic algorithm, hence the trained monkeys metaphor in the title. Being a nondeterministic search method, there is no guarantee of generating a useful solution, yet given a little direction and enough time it is able to solve hard problems. The controller is built using fuzzy logic rules, directed at manipulating the vehicle's angle of attack through the actuation of symmetric elevators. A preset structure for the rules is used whereby the design task is to configure the control surface through selection of the rule consequents. To direct the search for a controller design, the genetic algorithm uses simulated flight responses to a range of initial conditions, without linearization of the vehicle model and dynamics. Results for the genetic algorithm designed controller show longitudinal stability and disturbance rejection

Reactant Jetting in Unstable Detonation

We note the common existence of a supersonic jet structure locally embedded within a surrounding transonic flow field in the hitherto unrelated phenomena of unstable gaseous detonation and hypervelocity blunt body shock wave interaction. Extending prior results that demonstrate the consequences of reduced endothermic reaction rate for the supersonic jet fluid in the blunt body case, we provide an explanation for observations of locally reduced OH PLIF signal in images of the keystone reaction zone structure of weakly unstable detonations. Modeling these flow features as exothermically reacting jets with similarly reduced reaction rates, we demonstrate a mechanism for jetting of bulk pockets of unreacted fluid with potentially differing kinetic pathways into the region behind the primary detonation front of strongly unstable mixtures. We examine the impact of mono-atomic and diatomic diluents on transverse structure. The results yield insight into the mechanisms of transition and characteristic features of both weakly and strongly unstable mixtures

Boson Sampling with efficient scaling and efficient verification

A universal quantum computer of moderate scale is not available yet, however intermediate models of quantum computation would still permit demonstrations of a quantum computational advantage over classical computing and could challenge the Extended Church-Turing Thesis. One of these models based on single photons interacting via linear optics is called Boson Sampling. Proof-of-principle Boson Sampling has been demonstrated, but the number of photons used for these demonstrations is below the level required to claim quantum computational advantage. To make progress with this problem, here we conclude that the most practically achievable pathway to scale Boson Sampling experiments with current technologies is by combining continuous-variables quantum information and temporal encoding. We propose the use of switchable dual-homodyne and single-photon detections, the temporal loop technique and scattershot based Boson Sampling. This proposal gives details as to what the required assumptions are and a pathway for a quantum optical demonstration of quantum computational advantage. Furthermore, this particular combination of techniques permits a single efficient implementation of Boson Sampling and efficient verification in a single experimental setup

The Pre-Flood / Flood Boundary: As Defined in Grand Canyon and East Mojave

The singular events which occurred at the initiation of the Flood should have produced a geologic signature with at least five characteristics: 1) A mechanical-erosional discontinuity (ED) identified by regional structural analysis -- probably the most significant unconformity in any given area; 2) A time or age discontinuity (AD) identified by coarse sediments above the erosional unconformity containing lithified fragments of various sedimentary units found below the unconformity; 3) A tectonic discontinuity (TO), found at the erosional unconformity, distinguished by substantial regional tectonic disruption, especially at pre-Flood continental margins; 4) A sedimentary discontinuity (SO) consisting of a thick, fining-upward, clastic-to-chemical strata megasequence of regional to inter-regional extent defined at its base by a significant onlap unconformity; 5) A paleontological discontinuity (PO) marked by an increase in abundance of fossils and the first appearance of abundant plant, animal, and/or fungal fossils. In Grand Canyon of Arizona one of the most significant regional unconformities (ED) is found at or near the top of the Chuar Group. Associated with the unconformity is the Sixtymile Formation -- a tectonicsedimentary unit dominated by breccia with large clasts (TO) from the formations below it (AD). The Sixtymile Formation occurs at the bottom of a thick, regionally extensive series of strata called the Sauk Sequence, consisting of the fining-upward clastics, capped by carbonates (SO). Only low-abundance microfossils are known below the unconformity, whereas undisputed animal fossils occur only above the Sixtymile Formation, and there in great abundance (PO). We believe, therefore, that the Sixtymile Formation is the oldest preserved Flood deposit in Grand Canyon of Arizona. In the eastern Mojave Desert region of California, the Kingston Peak Formation is a very thick, regionally extensive clastic unit containing gigantic breccia clasts (TO) from the formations below it (AD). Associated with the formation is one of the region\u27s most prominent unconformities (ED). The Kingston Peak Formation is also the lowermost of a very thick, regionally extensive, transgreSSive, fining-upward, clastic-tocarbonate megasequence (SO) known as the Sauk Sequence. Only low-abundance microfossils are known from the Kingston Peak Formation and below, whereas common animal fossils are only found in rocks above the formation (PO). We believe, therefore, that the Kingston Peak Formation signals the beginning of the Flood in the Mojave region of California and should be correlated with the Sixtymile Formation of Grand Canyon of Arizona