Ferromagnetism in two mouse tumours

A variety of living organisms has been found recently that are biochemically able to precipitate the ferromagnetic mineral magnetite (Fe3O4). Originally discovered in the radular teeth of a primitive marine mollusc (Lowenstam, 1962), magnetite has since been reported in bacteria (Frankel, Blakemore & Wolfe, 1979), arthropods (Gould, Kirschvink & Deffeyes, 1978), and vertebrates (Walcott, Gould & Kirschvink, 1979; Zoeger, Dunn & Fuller, 1981; Walker & Dizon, 1981). Although the presence and biological origin of this material are clear, very little is yet known about the distribution or metabolic function of ferromagnetic minerals in vertebrate tissue. Magnetic remanence, which uniquely indicates the presence of ferromagnetic particles, has been previously detected in localized areas associated with the dura membranes of homing pigeons (Walcott et al. 1979) and dolphins (Zoeger et al. 1981), in pigeon neck muscles (Presti & Pettigrew, 1980), in the mid-brain of monkeys, and in human adrenal glands (Kirschvink, 1981). We report here the first discovery of anomalously high concentrations of ferromagnetic material in two strains of neoplasms, YC-8 lymphoma and Lewis lung tumour, as well as the apparent absence of such material in three human carcinomas (gastric, colon and renal)

Correlated Fermions on a Checkerboard Lattice

A model of strongly correlated spinless fermions hopping on a checkerboard lattice is mapped onto a quantum fully-packed loop model. We identify a large number of fluctuationless states specific to the fermionic case. We also show that for a class of fluctuating states, the fermionic sign problem can be gauged away. This claim is supported by numerically evaluating the energies of the low-lying states. Furthermore, we analyze in detail the excitations at the Rokhsar-Kivelson point of this model thereby using the relation to the height model and the single-mode approximation.Comment: 4 Pages, 3 Figures; v4: updated version published in Phys. Rev. Lett.; one reference adde

A simulation evaluation of a four-engine jet transport using engine thrust modulation for flightpath control

The use of throttle control laws to provide adequate flying qualities for flight path control in the event of a total loss of conventional flight control surface use was evaluated. The results are based on a simulation evaluation by transport research pilots of a B-720 transport with visual display. Throttle augmentation control laws can provide flight path control capable of landing a transport-type aircraft with up to moderate levels of turbulence. The throttle augmentation mode dramatically improves the pilots' ability to control flight path for the approach and landing flight condition using only throttle modulation. For light turbulence, the average Cooper-Harper pilot rating improved from unacceptable to acceptable (a pilot rating improvement of 4.5) in going from manual to augmented control. The low frequency response characteristics of the engines require a considerably different piloting technique. The various techniques used by the pilot resulted in considerable scatter in data. Many pilots readily adapted to a good piloting technique while some had difficulty. A new viable approach is shown to provide independent means of redundancy of transport aircraft flight path control

Nitrogen Response Efficiencies from Grazed Dairy Pastures under Dry Conditions

Experiments were conducted within a long-term nitrogen (N) fertiliser experiment under grazing. The objective was to examine N response efficiencies (kg dry matter (DM)/kg N) and herbage crude protein (CP) content to fertiliser N applied under dry soil conditions (gravimetric soil moisture content of 17% at 10cm; soil field capacity = 38% and wilting point = 11%) during autumn (April 1999) and late spring (November 1999) in southeastern Australia. Visually, N treated plots were greener in colour than control (no N) plots. No differences were recorded in primary or residual DM yields, N response efficiencies, and pasture growth rates between N fertilised plots and control plots for both autumn and late spring applications. Fertiliser N, however, had increased herbage CP content six weeks after application in autumn, but had no effect on primary (autumn and late spring applications) or residual CP content in late spring. It was concluded that N fertiliser applications under dry soil conditions are economically and environmently questionable

Nitrogen Fertiliser Effects on Perennial Ryegrass Nutritive and Nitrate Content during the Cool Season

A study was undertaken to determine the effects of differing levels of nitrogen (N) application (0 (N1), 25 (N2), 50 (N3) and 75 kgN/ha (N4)) during late autumn (T1), early (T2) and late winter (T3) on the nutritive characteristics and nitrate content of perennial ryegrass. Changes in crude protein (CP) for all treatments at each application time were similar irrespective of level of N application. At the commencement of all treatments, the existing CP content was highest in N3, followed by N2, N1 and N0. Nitrate content decreased throughout T1 primarily due to dry conditions, whilst during T2, levels for N3 and N2 were significantly (P \u3c 0.05) higher than N1 and N0. During T3, nitrate content increased for all treatments throughout the 28 day period, with highest nitrate levels being observed during T3. The findings indicate that N fertiliser did not elevate nitrate content in perennial ryegrass to levels considered toxic. It is likely that environmental effects (rain and temperature) impacting on soil N mineralisation may have a greater impact on nitrate content than fertiliser N

Acceptance and commitment therapy delivered in a dyad after a severe traumatic brain injury: a feasibility study

Objective: There is a high prevalence of complex psychological distress after a traumatic brain injury but limited evidence of effective interventions. We examined the feasibility of Acceptance and Commitment Therapy after a severe traumatic brain injury using the criteria, investigating a therapeutic effect, and reviewing the acceptability of measures, treatment protocol, and delivery method (in a dyad of two clients and a therapist). Method: Two male outpatients with severe traumatic brain injury and associated psychological distress jointly engaged in a seven session treatment program based on Acceptance and Commitment Therapy principles. Pre- and post-treatment measures of mood, psychological flexibility, and participation were taken in addition to weekly measures. Results: The intervention showed a therapeutic effect with one participant, and appeared to be acceptable for both participants with regard to program content, measures, and delivery mode by in a dyad. One participant showed both significant clinical and reliable change across several outcome measures including measures of mood and psychological flexibility. The second participant did not show a reduction in psychological inflexibility, but did show a significant drop in negative affect. Significant changes pre- to post-treatment for measures of participation were not indicated. Qualitatively, both participants engaged in committed action set in accordance with their values. Conclusions: This study suggests that Acceptance and Commitment Therapy may be feasible to be delivered in a dyad with individuals who have a severe traumatic brain injury. A further test of its potential efficacy in a phase II clinical trial is recommended

Markov vs. nonMarkovian processes A comment on the paper Stochastic feedback, nonlinear families of Markov processes, and nonlinear Fokker-Planck equations by T.D. Frank

The purpose of this comment is to correct mistaken assumptions and claims made in the paper Stochastic feedback, nonlinear families of Markov processes, and nonlinear Fokker-Planck equations by T. D. Frank. Our comment centers on the claims of a nonlinear Markov process and a nonlinear Fokker-Planck equation. First, memory in transition densities is misidentified as a Markov process. Second, Frank assumes that one can derive a Fokker-Planck equation from a Chapman-Kolmogorov equation, but no proof was given that a Chapman-Kolmogorov equation exists for memory-dependent processes. A nonlinear Markov process is claimed on the basis of a nonlinear diffusion pde for a 1-point probability density. We show that, regardless of which initial value problem one may solve for the 1-point density, the resulting stochastic process, defined necessarily by the transition probabilities, is either an ordinary linearly generated Markovian one, or else is a linearly generated nonMarkovian process with memory. We provide explicit examples of diffusion coefficients that reflect both the Markovian and the memory-dependent cases. So there is neither a nonlinear Markov process nor nonlinear Fokker-Planck equation for a transition density. The confusion rampant in the literature arises in part from labeling a nonlinear diffusion equation for a 1-point probability density as nonlinear Fokker-Planck, whereas neither a 1-point density nor an equation of motion for a 1-point density defines a stochastic process, and Borland misidentified a translation invariant 1-point density derived from a nonlinear diffusion equation as a conditional probability density. In the Appendix we derive Fokker-Planck pdes and Chapman-Kolmogorov eqns. for stochastic processes with finite memory

Ram-recovery Characteristics of NACA Submerged Inlets at High Subsonic Speeds

Results are presented of an experimental investigation of the characteristics of NACA submerged inlets on a model of a fighter airplane for Mach numbers from 0.30 to 0.875. The effects on the ram-recovery ratio at the inlets of Mach number, angle of attack, boundary-layer thickness on the fuselage, inlet location, and boundary-layer deflectors are shown. The data indicate only a slight decrease in ram-recovery ratio for the inlets ahead of or just behind the wing leading edge as Mach number increased, but showed large decreases at high Mach numbers for the inlets aft of the point of maximum thickness of the wing